COMPARISON OF CAUDIAL ANALGSIA AND INTERAVENOUS

DICLOFENAC FOR POSTOPERATIVE PAIN RELIEF IN PAEDIATRIC

PATIENTS

BY

DR. AROSO BUNMI KULE

MBBS (MAIDUGURI)

NOV. 2010

SUMMARY

The treatment of postoperative pain in children has attracted special attention for

many decades. Out-patients undergoing day care procedure require perioperative

analgesic technique that is effective, has minimal side effects and safe. Adequacy

of post operative management is one of the important factors determining when a

patient can be safely discharged from the out-patient facility7.

This is a randomised comparative study on postoperative analgesic efficacy and

adverse events associated with caudal block and intravenous diclofenac given

before surgical incision in 60 ASAI & II children aged 1-7years scheduled for day

case herniotomy.

No premedication was given to any of the patients. Anaesthesia was achieved with

3.5% halothane in 100% oxygen or intravenous propofol 3mg/kg. An LMA was then

inserted and secured with adhesive tape. Caudal block with 0.125% bupivacaine

(1ml/kg) was given in GroupI (n=30) and intravenous diclofenac (1ml/kg) in Group

II (n=30).

Pain was assessed by two different methods- mCHEOPS and verbal rating scale,

during the first 4 hours in the recovery room and up to the 24th hour at home by

the parents. Parents were to rate the pain as none, mild, moderate, severe and very

severe. Total analgesic consumption at home among the two groups was

compared.

The mean duration to first analgesia in the caudal group was 239±24.6 minutes

compared to 167.6±43.2 (SEM) minutes in the diclofenac group (p <0.0001).

This study showed immediate postoperative pain control was significantly better in

the caudal group than the diclofenac group.

The mean pain score in the first 2 hours in the caudal group was 0.0±0.0 while it

was 2.8± 2.9 in the diclofenac group (p<0.001). Details of Paracetamol consumption

at home in the latter part of the study showed that diclofenac group had better

pain control than the caudal group.

No complication was attributed or seen in any of the techniques in the immediate

and in the late postoperative

INTRODUCTION

Pain following surgical procedures in children has aroused growing concern in the

past fifteen years.1

In describing how patients feel after surgery, Armitage2 stated that “slapping the

patient in the face and telling him or her that it is all over is a complete inversion of

the truth” because as far as the patient is concerned, “it is often just the beginning”.

There has been increasing international acknowledgement, by the International

Association for the Study of Pain (IASP) and World Health Organization (WHO) that

pain relief should be a basic human right. The Society of Paediatric Anaesthesia3, at

its 15th annual meeting at New Orleans, Louisiana (2001) clearly defined the

alleviation of pain as a “basic human right”, irrespective of age, medical condition,

treatment or medical institution.

Effective post-operative management has humanitarian benefit but there are

additional medical and economic benefits for rapid recovery and discharge from

hospital. Effective Pain Management is now an integral part of modern surgical

practice. Post-operative pain management not only minimizes patients’ suffering

but also reduces morbidity and facilitates rapid recovery and early discharge from

hospital. Post-operative pain relief has always posed a difficult challenge to

surgeons, anaesthesiologists and recovery room nurses. Though the current array

of analgesic drugs and techniques is impressive, effective management of post-

operative pain still poses unique challenges. Few studies have been done locally on

this subject.

Historically, children have always been under-treated for pain and for painful

procedures because of the wrong notion that they neither suffer, feel pain, respond

to, nor remember the painful experiences to the same degree as adult. Unproven

safety and efficacy of analgesics and worries about the risk of opioid induced

respiratory depression add to the reasons for the under-treatment of pain in

children. Moreover, children often cannot or would not express their feelings and

degree of pain; they may underrate their own pain because of the fear of the

consequences. Anand’s4 landmark work demonstrated the increase in morbidity

and mortality that resulted following inadequate opioid use during and after major

surgery in infants. Taddio5 also showed that unanaesthesized circumcision of new-

borns resulted in increased crying and behavioural response to the pain of

immunization needle 4-6 months later. Thus it becomes extremely important to

ensure that pain is treated in the paediatric patient to the greatest extent possible.

In view of this, different drugs like acetaminophen, non-steroidal anti-

inflammatory drugs (NSAIDs), ketamine, and different regional techniques

(infiltration, field block, nerve block, caudal block) have been used to treat pain in

infants and children following surgery.6

Caudal anaesthesia is one of the most popular regional blocks in children. This

technique is usually performed after inhalational or intravenous induction of

anaesthesia. It is a useful adjunct during general anaesthesia and for providing

postoperative analgesia after genital, lower abdominal and lower limb operations.

Diclofenac, a non-steroidal anti-inflammatory drug (NSAID) is effective in relieving

post-operative pain. It is suitable for day-case surgery because of its opioid sparing

effects, minimal sedation and lack of emetic side effect.

The use of these two techniques (caudal block and intravenous (i/v) diclofenac)

precludes the use of narcotic analgesics often used to provide quick relief of pain.

The common side effects of narcotics like nausea, vomiting, and respiratory

depression are uncommon with the techniques under investigation.

This study was designed to compare postoperative analgesic effectiveness of a

frequently practised technique caudal block with bupivacaine and I/V diclofenac to

determine which provided superior analgesia in children under going day case

herniotomy.

Adequate post-operative pain control is an important factor in determining when

a patient can safely be discharged from an outpatient facility.7

AIMS AND OBJECTIVES

AIM

To compare the analgesic efficacy of caudal block using bupivacaine (0.125%) with

that of I/V diclofenac in Nigerian children aged between 1 & 7years.

OBJECTIVES

1. To compare the post-operative analgesic effects of caudal block with

diclofenac using appropriate pain scores.

2. To compare the duration of action and adverse events following

administration of plain bupivacaine (in caudal block) and intravenous

diclofenac.

LITERATURE REVIEW

The International Association for the Study of Pain (IASP) defined pain as an

“unpleasant, sensory and emotional experience associated with actual or potential

tissue damage or described in terms of such damage”.8 Pain is a personal,

subjective experience that involves sensory, emotional and behavioural factors

associated with actual or potential tissue injury.9

Pain is one of the commonest symptoms that lead a patient to seek medical advice

and whatever the cause it demands relief. This was emphasized by John Dryder

(1631 – 1701) who said “for all the happiness mankind can gain is not pleasure but

in rest from pain”.

Pain has been described as one of the main post-operative adverse effects that

cause distress to patients.10

An increasing number and more complex operations are being performed on

outpatient basis where the use of conventional opioid-based intravenous analgesia

is not an ideal technique for pain management. This expanding population requires

a perioperative regimen that is highly effective, has minimal side effects, is

intrinsically safe and can be easily managed away from hospital.11

Post-operative pain is an acute pain associated with a brief episode of tissue injury

or inflammation such as surgical trauma and usually ends with tissue healing.

ANATOMY OF THE CAUDAL SPACE: The sacrum results from the fusion of 5 sacral

vertebrae. The sacral hiatus is the failure of the laminae of S5 and part of S4 to fuse

in the mid-line forming an inverted V-shaped bony defect. It is situated 1-

2centimetres above the gluteal crease, superior to the coccyx and between the

prominent sacral cornuae and is covered by the posterior sacro-coccygeal ligament

(a functional counterpart of the ligamentum flava). The sacral canal contains the

terminal portion of the dural sac and venous plexus (part of valveless internal

vertebral venous plexus).12 This space has been used to provide regional

anaesthesia and analgesia for surgeries involving the lower abdomen, genito-

urinary tract and lower limbs. It is the sacral portion of the epidural space, and the

anatomy is more easily appreciated in infants and children.

PHYSIOLOGY OF PAIN AND PAIN PATHWAY: Pain is a protective event. It enables

the organism to localize noxious stimuli rapidly and accurately withdraw from the

stimulus in order to avoid or reduce tissue damage.

Most pain arises in pain receptors (nociceptors) widely distributed in the skin and

musculoskeletal system. Those responding to pin prick and sudden heat

(thermomechano receptors) are transmitted by fast conducting A-delta fibres and

is responsible for rapid pain sensation and reflex withdrawal. Receptors responding

to pressure, heat, cold and chemical stimuli (e.g. histamine, prostaglandins, acetyl-

choline, substance P etc) and tissue damage (polymodal receptors) are associated

with ummyelinated C-fibers (slow conducting fibres) and are responsible for slow

pain sensation and immobilization of the affected part.13

The A-delta primary afferents enter the dorsal horn of the spinal cord and synapse

at laminae I, V and X (first order neuron). Conduction continues along the

secondary afferent fibres via the spinothalamic tract which is monosynaptic as it

ascends to the posterior thalamic nuclei (second order neuron). From here,

neurons synapse with tertiary afferents to the somatosensory post-central gyrus in

the cortex (from the thalamus to the cortex – third order neuron).

C-fibres synapse with cells in laminae II and III (substantia gelatinosa) of the dorsal

horn. Secondary afferents ascend via the paleospinothalamic tract which is

polysynaptic, to the medial thalamic nuclei. It has collaterals that also project to

the mid-brain, pontine and medullary reticular formations, the periaqueductal grey

area and the hypothalamus, where they synapse on to neurons that project to the

forebrain limbic structures. This system is primarily involved with reflex responses

concerned with respiration, circulation and endocrine function. They also engage

descending modulatory systems. All are involved in producing the emotional and

behavioural response to pain.14 The ability of the somatosensory system to detect

noxious and potentially tissue damaging stimuli is an important protective

mechanism that involves multiple interaction of peripheral and central

mechanisms. The detection of noxious stimuli requires activation of peripheral

sensory organs (nociceptors) and the transduction of the energy to electrical signals

for transmission to the central nervous system. Once transduced into electrical

stimuli, conduction of neuronal action potential is dependent on voltage- gated

sodium channels.9 Inhibition of nociceptive information from thalamus to the

dorsal horn neurons has been reported to originate from these areas: the

periaqueductal grey matter (mid brain) or the periventricular grey matter lateral to

the hypothalamus. Inhibitory neuro-transmitters of the descending pathways

include endorphins, enkephalins, glycine, serotonin and gama-aminobutyric acid

(GABA).15

The discovery of these neurotransmitters led to the development of some of the

drugs used in the management of postoperative pain.

FACTORS AFFECTING POST-OPERATIVE PAIN

Numerous factors influence the intensity, quality and duration of pain. Despite the

availability of many effective analgesic agents, many patients (33-75%) continue to

suffer severe pain post-operatively.16 Famewo17 investigated the incidence of post-

operative pain among Nigerian patients and found the incidence of moderate to

severe pain to be 68%.

Rawal18 presented the following list of factors that affect the occurrence, intensity,

quality and duration of post-operative pain.

1. The physiological and psychological makeup of the patient

2. Preoperative pharmacological and psychological preparation of the patient

3. The site, nature and duration of surgery

4. Occurrence of post operative complication

5. Perioperative anaesthetic management, and

6. The quality of post-operative care.

Pavlin et al19 surveyed ambulatory surgery patients in order to determine pain

severity, analgesic use, relationship of pain to duration of recovery, and the relative

importance of various factors in predicting these outcomes. Multivariate regression

analysis was used to determine unique contributions of predictor variables to

outcome. Surgical procedures included knee arthroscopy, hernia surgery, surgery

for breast disease, and plastic surgery. Maximum pain (on a scale of 0-10) varied

from 2.3±0.5 to 5.1±0.5 (mean ± SE), depending on surgical procedure. Of the

various factors evaluated as predictors of pain severity, the type of surgery

performed was the most important; pain was most severe after hernia,

laparoscopy, and plastic surgery. In contrast, Famewo17 in a prospective study of

200 patients in Ibadan found that surgery of anorectal region was the most painful.

Pain following operations on the lower abdomen, head and neck were less severe.

Another factor that determines the severity of postoperative pain is preoperative

depression and anxiety. One study showed that patients who were anxious and

depressed preoperatively experienced more pain than normal individuals who had

undergone similar procedure.20

Other factors that can predict the occurrence of post-operative pain include:

a) Age- patients over 50yrs require less analgesic than younger patients.21

b) Gender - studies have shown that women exhibit higher pain scores

than men.22

Pain in children is determined by many factors, including the medical condition,

type of procedure performed, and attitude of health care professionals toward pain

management. Compared with adults undergoing similar procedures less potent

analgesic regimens are usually ordered for and given to children.23

MEASUREMENT OF POSTOPERATIVE PAIN

The definition of pain underlies the complexity of its measurement. Pain is an

individual and subjective experience modulated by physiological, psychological and

environmental factors such as previous events, culture, prognosis, coping

strategies, fear and anxiety.9 Therefore, most measures of pain are based on self

report.

To treat pain effectively its severity must be measured. The essence of pain

measurement is to assign a value to pain in order to aid the overall assessment.

Several scoring systems and methods are available: what the patient reports about

his/her experience, the way a patient reacts in response to pain (behavioural

measures), and how the body responds to pain (physiological and biological

measures).

No one method to assess pain offers an error-free measure of paediatric pain.

Assessment tools should be appropriate for the child’s age and cognitive

development. A variety of assessment tools are available for different age groups.

As with adults, a self –report tool provides the most reliable and valid estimate of

pain intensity, quality and setting.24 Self report tools for children over the age of

4yrs include—Oucher, the Poker Chip tool and a Face Scale. Children over the age

of 7or 8yrs can use Numerical Rating Scale (NRS), a horizontal word-graphic rating

scale.

Observation of behaviour is the primary assessment method for the non-verbal

child. These observations focus on vocalizations, verbalizations, facial expressions,

motor responses and activities e.g. modified Children’s Hospital of Eastern Ontario

Pain Scale (mCHEOPS), Face, Leg, Activity, Cry and Consolability (FLACC) etc. These

measures lead to sensitive and consistent results if done properly.25

DeLoach, et al26 studied 60 adult patients in the immediate postoperative period

comparing Visual analogue scale (VAS) scores versus 11-point numeric pain scales.

The data collected were the repeatability in VAS scores over a short time interval

and change in VAS scores from one assessment period to the next versus numerical

report of change in pain. The correlation coefficients for VAS scores with the 11-

point pain scale were 0.94, 0.91, and 0.95. The repeatability coefficients were 17.6,

23.0 and 13.5 mm. Of the 56 patients who completed all the three assessments,

only 16 (29%) had repeatability within 5mm on all three. They concluded that the

visual analogue scale correlates well with a verbal 11-points scale but an individual

determination has an imprecision of ±20mm.

Recording pain intensity as the fifth vital sign aims to increase awareness and

utilization of pain assessment and may lead to improved management of acute

pain.27

Other methods (subjective) of pain assessment are: Unidirectional measurement

of pain (pain as self report on a single scale), and Multidimensional i.e. pain as self

report on Multiple dimensions.

The unidirectional measurement of pain includes: Verbal rating scales25 (VRS). This

uses words to describe the magnitude of pain or the degree of pain relief. It grades

pain as none, mild, moderate and severe. Pain relief may also be graded as VRS-

none, mild, moderate and complete. VRS has the advantage of being quick and

simple; it may be used in elderly or visually impaired patients and in some children.

However, the limited number of choices in VRS compared with numerical scales

may make it more difficult to detect differences between treatments.28

Numerical rating scales29 (NRS) have both written and verbal forms. Patients rate

the pain intensity on a scale of 0 to 10, where 0 represents ‘no pain’ and 10

represent ‘worst pain imaginable; or their degree of pain relief from 0 representing

‘no relief’ to 10 representing ‘complete relief’.

Visual analogue scales30 (VAS) consist of a 100mm horizontal line with verbal

anchors at both ends. The patient is asked to mark the line and the score is the

distance in millimeters from left side of the scale to the mark. It is the most

commonly used scale for rating pain intensity – ‘no pain’ at the left end and ‘worst

pain’ possible at the right. VAS ratings greater than 70mm indicate ‘severe pain’

and 0-5mm ‘no pain’, 5-44mm ‘mild pain’ and 45-69 moderate pain. These scales

have the advantage of being simple and quick to use. They allow for a wide choice

of ratings and avoid imprecise descriptive terms.

VAS has been shown to be a valid measure of pain intensity. Studies demonstrated

good correlation between VAS and other measures of pain intensity.31 However,

the scales require concentration and coordination, and are unsuitable for children

under 5yrs.32

A prospective study defined in centimetres what constituted mild, moderate, and

severe pain in children (aged 5 to 16years), using the Colour Analogue Scale (CAS)

for pain. One hundred and sixty-nine children with complaint of pain were recruited

from the Paediatric Emergency Department. The children were asked to mark on a

standardized CAS and also to describe the pain as “none”, “mild,” “moderate,” or

“severe.” Children who considered their pain to be mild (n= 34), had a median score

of 3.5cm and a mean score of 3.47. For those with moderate pain (n= 68), a median

score of 6.0, and a mean score of 6.04 were documented and those with severe

pain (n= 67), the median score was 8.5cm, and the mean score was 8.25cm. It was

concluded that the study quantified what constituted mild, moderate, and severe

pain on the CAS.33

An accurate evaluation using assessment scores appropriate to the childrens’ age

is needed. It is more difficult to evaluate pain in preverbal children; therefore

different ages demand different methods.34 Behavioural and physiological status is

adequate for neonates, infants and preschool children. Their score is based on

physiological parameters such as heart rate (HR), blood pressure (BP), sweating,

crying, patient’s position and facial expression. The most popular scales are the

Children’s Hospital of Eastern Ontario Pain Scale (CHEOPS)35 and the Objective Pain

Scale (OPS).36 Children aged 4-7 years can differentiate the presence or absence of

pain. They can also express the intensity of pain in form of nil, mild, moderate and

severe. Faces pain scale or Oucher scale can be used in this age group. Children of

5years or more can operate visual or colour analogue scales for expression of pain.

The “smiley faces” depicts a range of numbered faces that the child can relate to.

The Colours Analogue scale allows children to associate red and green with pain

intensity. Older children>7yrs can express intensity, location, and quality of pain.

Any scoring system such as horizontal VAS, vertical colour analogue scale and self

reporting are effective and reliable in this age group.37

ADVERSE EFFECTS OF PAIN

The physiological effect of pain results from injury, as a consequence of activation

of both the peripheral and central nervous systems. There is release of

neuroendocrine hormones and local release of cytokines (interleukin, tumour

necrosis factors) at the site of injury leading to physiological alterations in major

organ systems. Pain from surgical stimuli can activate sympathetic nervous systems

and increase heart rate, force of cardiac contraction, and blood pressure.

Sympathetic activation increases myocardial oxygen consumption and reduces

myocardial oxygen supply with the risk of myocardial ischaemia in patients with

pre-existing heart disease. In addition, there is reduced gastrointestinal motility

leading to ileus. Reduced coughing and deep breathing can lead to hypoventilation

and retention of secretions with resultant atelectasis and subsequent ventilation

perfusion mismatch.

Psychological changes associated with acute pain include inability to sleep,

demoralization, helplessness; loss of self control, inability to think and interact with

others.38 Effective analgesia is capable of modifying many of the physiological and

psychological responses associated with acute pain.10

TREATMENT OF POST OPERATIVE PAIN IN CHILDREN

Pain should be treated on humanitarian grounds, though this can be difficult to

prove in terms of evidence-based medicine. However effective postoperative pain

relief is fundamental to good quality patient care. There is increasing evidence

relating good postoperative analgesia to reduced clinical morbidity. Some

authorities suggest that there may be economic benefits with enhanced patient

well-being and rehabilitation.6 ,19 The aim of postoperative pain relief is to provide

subjective comfort in addition to inhibiting trauma-induced nociceptive impulses

that induce autonomic and somatic reflex responses to pain.

Perioperative analgesia has traditionally been provided by opioid analgesics.

However, extensive use of opioids is associated with complications like ventilatory

depression, drowsiness, sedation, post-operative nausea and vomiting, pruritus,

urinary retention, ileus and constipation that can delay hospital discharge.6 Hence,

anaesthetists and surgeons are turning to non-opioid analgesic techniques as

adjuvants for managing pain during the perioperative period. Effective treatment

of post-operative pain also includes good nursing care, and appropriate

pharmacological techniques.

Pharmacological methods include use of opioid and non-opioid analgesics like

paracetamol (PCM), non-steroidal anti-inflammatory drugs (e.g. ketorolac,

diclofenac, cyclo-oxygenase 2 inhibitors).39 Balanced (multimodal) analgesia uses 2

or more analgesic agents that act by different mechanisms to achieve a superior

analgesic effect e.g. PCM and NSAIDs for low intensity pain, regional block plus

small dose opioid to minimize adverse effects of medications.40

Regional analgesia involves the use of local anaesthetic agents like lignocaine,

bupivacaine, levobupivacaine and ropivacaine for wound infiltration, nerve block

and caudal blockade for the management of perioperative pain. Local anaesthetics

(LAs) decrease post operative pain when placed at the surgical site. Kushimo et al41

studied incisional infiltration with bupivacaine for postoperative analgesia in

children undergoing herniotomy (25 patients had infiltration with 0.25% and the

other 25 patients placebo). They found that infiltration with 025% bupivacaine

provided good post operative analgesia. Anatol et al42 evaluated the relative

effectiveness of 3 techniques of regional anaesthesia using 0.5% plain bupivacaine

(2mg/kg) for the provision of postoperative analgesia in 183 children for groin

surgery. These children were randomly assigned to one of three groups. Group A

had wound infiltration, Group B received regional nerve block and Group C had

combination of both techniques (A&B). Postoperative pain was assessed using

Children’s Hospital of Eastern Ontario Pain Score (CHEOPS) behavioural scale at half

hourly intervals until discharge home. Satisfactory pain control was defined as

CHEOPS score of ≤ 6. They found that all the three methods achieved analgesia with

80% of pain scores meeting their definition of satisfactory pain control and none of

the techniques enjoyed any apparent advantage.

It has been suggested that performing neural block with LAs before surgical incision

prevents nociceptive input from altering excitability of the central nervous system

by pre-emptively blocking the N-methyl-d-aspartate-(NMDA) induced “wind-up”

phenomenon and subsequent release of inflammatory mediators43. The concept of

pre-emptive analgesia or treating pain by preventing the establishment of central

sensitization may be very important in diminishing postoperative pain. Various

researchers who investigated pre-emptive analgesia concluded that it improved

postoperative pain control.44,45 Harrison and colleagues45 evaluated the effect of

ilioinguinal and iliohypogastric nerve block and wound infiltration with 0.5%

bupivacaine for postoperative pain after hernia repair. Their finding was good

postoperative pain control in those patients that had preincisional nerve block as

well as a reduced need for oral opioid-containing analgesics in the post discharge

period compared to those that had post operative wound infiltration.

In another study 40 adult patients were given 0.5% plain bupivacaine 20ml via low

thoracic extradural catheter and diclofenac suppository 100mg either 30 minutes

before incision (group1) or 30 min after incision (group2). It was found that the

combination of extradural block and diclofenac suppository given before did not

appear to produce a clinically pre-emptive analgesic effect.46

Local anaesthetics (LAs), opioids or a combination of both have been used to

provide analgesia intraoperatively and postoperatively. The addition of an opioid

analgesic has been demonstrated to improve the efficacy of bupivacaine for

epidural analgesia regardless of the opiate chosen. Berti et al47 observed that

Postoperative analgesia using continuous infusion of bupivacaine 0.125% (4mls/hr)

with either 0.05 mg/ml morphine or 0.005 mg/ml fentanyl provided adequate and

similar pain relief in a prospective randomized double blind study involving 30 ASA

physical status 1&2 adult patients undergoing hip replacement. VAS, respiratory

rate, pulse oximetry, and rescue analgesics were the parameters monitored.

BUPIVACAINE HCL is an amide group local anaesthetic (LA) agent synthesized by

Ekenstan in 1957. It is a racemic mixture of R & S enantiomers. Its onset of action

is slower but of longer duration of action than lignocaine lasting 3-4hours for

extradural block and up to 12 hours for some nerve blocks. It binds extensively to

tissues and plasma protein (95%), with a pKa of 8.1 and this is associated with its

slow onset of action. It is highly soluble in lipid and is metabolized by the liver with

a small amount excreted unchanged in urine.13 It has been used extensively in

different forms of regional techniques such as infiltration,41 nerve block, epidural

analgesia and caudal block in children for postoperative pain management. Its high

lipid solubility and protein biding are responsible for rapid onset of action and

prolonged duration of action. Maximal dose is 2mg/kg. The most common adverse

effects are central nervous system toxicity, hypotension, respiration paralysis, and

cardiac arrest.

DICLOFENAC

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) bearing a carboxylic

acid functional group, with an approximate relative COX-1/COX-2 specificity ratio

of one.48 It is suitable for the management of mild to moderate pain. Its opioid-

sparing effect and availability in parenteral form makes it ideal for day case short

stay admissions for elective surgery.49 The action of one single dose is much longer

(6-8hr) than the very short half-life that the drug indicates.

Diclofenac has analgesic, anti-inflammatory, antirheumatic and antipyretic

activities. It is metabolized in the liver. It is a non-selective inhibitor of both cyclo-

oxygenase (COX I and 2), which catalyze prostaglandin synthesis in the peripheral

tissues, nerves and the central nervous system. This inhibition accounts not only

for the analgesic and anti-pyretic effects but also for side effects such as gastric

mucosal damage and renal toxicity.50 Other mechanisms of action, which are

independent of any effect on prostaglandin, include effects on basic cellular and

neuronal processes.

Adverse effects are more common with long-term use. In the perioperative period,

the main concerns are renal impairment, interference with platelet function, peptic

ulceration and bronchospasm.51

Caudal anaesthesia is one of the most popular regional blocks in children. It is

usually performed after inhalational or intravenous (I/V) induction of general

anaesthesia. It is a useful adjunct of general anaesthesia and for providing post

operative analgesia after genital, lower abdominal and lower limb operations.

The quality and level of caudal analgesia is dependent on the dose, volume and

concentration of the injected drug. In order to predict the height of spread of

caudal block, many anaesthetic text books used formulae based on original work

of Armitage.52 The most widely used clinical formula advocates 0.5ml/kg for

lumbosacral block, 1ml/kg for a thoraco-lumbar and 1.25ml/kg for a midthoracic

block of 0.25% bupivacaine to a maximum of 20ml.

Verghese et al53 compared the intensity and level of caudal blockade when two

different volumes and concentrations of a fixed dose of bupivacaine were used in

50 children aged 1-6yrs old undergoing unilateral orchidopexy. Group 1 received

caudal block with fixed 2mg/kg dose bupivacaine (0.8ml/kg of 0.25%) while group

II received 0.2% bupivacine (1ml/kg). They found that those who received a caudal

block with the larger volume of diluted bupivacaine had a significantly more

effective block than the smaller volume of standard 0.25% solution. The findings

showed the quality and level of caudal blockade is dependent on the dose, volume

and concentration of injected drug. In contrast, Thomas and colleagues54 noted

that the anatomical height by caudal solutions did not seem to be a function of the

volume injected within the range of 0.5-1ml/kg. It was argued that many factors

such as leak of the solution through the foraminae and into the surrounding tissue

could be responsible.

Different local anaesthetics like ropivacaine and levobupivacaine have been

investigated and compared with the commonly used agent bupivacaine in caudal

block, in terms of safety complications and duration of action. Invani and

colleagues55 compared ropivacaine with bupivacaine for paediatric caudal block in

245 patients ASA 1, aged 1-10 years undergoing elective minor surgery. Group A

received 0.25% ropivacaine (1ml/kg) while Group B received 0.25% bupivacaine

2.5mg/kg (1ml/kg). The mean time to first analgesia after bupivacaine was

233.2min compared with 271.9min for ropivacaine. In conclusion ropivacaine

produced longer duration of analgesia than bupivacaine. This result was not

validated in a randomized double blind study which compared levobupivacaine,

ropivacaine and bupivacaine (0.25% each), by the caudal route in children less than

10yrs for subumbilical surgery. The outcome of the study showed bupivacaine

produced a significant incidence of residual block and analgesic effect compared

with levobupivacaine and ropivacaine.56

The route of administration of the LA is also known to influence the quality and

duration of post-operative analgesia. Splintest et al57 compared the effect of local

anaesthesia (LA) with that of caudal anaesthesia on postoperative care in 202

children undergoing inguinal hernia repair. LA techniques included ilioinguinal and

iliohypogastric nerve blocks and subcutaneous injection by surgeon. Dose of caudal

bupivacaine was 1ml/kg of 0.25% solution. Post-operative pain was assessed with

mCHEOPS. They found that the children who received caudal anaesthesia required

less acetaminophen for postoperative pain control.

In a similar study in Benin-City, which compared postoperative analgesia in children

using caudal anaesthesia versus local infiltration in 62 children undergoing

unilateral herniotomy and orchidopexy, postoperative pain assessment did not

show any significant difference between the two groups.58

A draw back of caudal block apart from weakness of lower limbs with single shot

caudal block is its short duration of action. The duration can be prolonged by adding

drugs such as ketamine (preservative free), clonidine an α2 agonist, neostigmine,

midazolam, fentanyl, morphine etc.59

Ketamine has been used in the epidural space to improve postoperative analgesia.

Analgesic effects of ketamine are mediated through N-methyl-D-aspartate

receptors in the spinal cord. Konig et al60 compared the clinical effectiveness of

ketamine after caudal and intramuscular (i/m) administration in 42 children ages 1

– 7yrs for inguinal hernia repair. They found that caudal ketamine provided better

intraoperative and postoperative analgesia as against i/m ketamine administration.

Another comparative study on caudal ketamine, caudal bupivacaine versus i/v S (+)

ketamine in 60 children for subumbilical surgery, showed that the median time to

first analgesia was significantly longer in caudal ketamine (10hrs) than i/v ketamine

(4.63 or bupivacaine 4.75). Fewer doses of analgesia were required over the first

24hrs by subjects in the caudal ketamine compared with the i/v ketamine or

bupivacaine.61

Naguib et al62 in Egypt compared the efficacy of caudal midazolam with caudal

bupivacaine in 1995 among 45 children. It was observed that there was no

difference in quality of pain relief, post-operative behaviour or analgesic

requirement between the 2 groups.

Intravenous and caudal Tramadol have also been compared in children aged

between 1 - 3yrs.63 Tramadol was administered either preoperatively or

postoperatively. Caudal tramadol provided better and longer lasting post-operative

analgesia than intravenous (iv) tramadol. No clinical benefit was found between

preoperative and post-operative caudal.

Posser and colleagues64 investigated the use of caudal Tramadol for postoperative

analgesia in paediatric hypospadias surgery. Ninety healthy boys aged 13-53

months were randomly allocated into one of 3 groups. Group1 received

bupivacaine 2mg/kg, Group2 received tramadol 2mg/kg and Group3 received

bupivacaine + tramadol. Pain scores were assessed with Toddler Preschool

Postoperative Pain Scale (TPPPS) pain score. They found that there was no

difference in pain relief between tramadol and bupivacaine.

Diclofenac, a non-steroidal anti-inflammatory drug is now being used in some

countries (USA, UK, and India) 65 for day case surgery both in paediatric and adult

patients because of its potency and less side effects associated with its use as

compared with the use of opioids.

Ryhänen et al66 in Turkey compared post operative pain relief between caudal

bupivacaine 0.25% as 1ml/kg and i.m. diclofenac sodium 1mg/kg in 250 children for

herniotomy and orchidopexy. Post-operative pain assessment showed that

bupivacaine provided better analgesia during the early post-operative hours but

later the need for rescue analgesia (pethidine) was lower among children who

received i.m. diclofenac. This lower need for late rescue analgesia with i.m.

diclofenac was also observed when the opioid used was fentanyl. Campbell67

compared analgesic efficacy of bupivacaine + fentanyl (BF) and bupivacaine + im

diclofenac (BD). Children who received bupivacaine + fentanyl were more pain free

during the early post operative hours but later the need for rescue anagelsia was

lower among children who received diclofenac.

Diclofenac has also been used effectively as suppositories. Borker,68 in Mumbai,

India investigated the analgesic efficacy of caudal block versus diclofenac

suppository with infiltration among 50 children aged 3-13 years undergoing

laparoscopy. Results of post operative pain assessment were compared in the 2

groups. Twelve per cent of caudal block patients and 20% of diclofenac patients

needed rescue analgesic, a statistically insignificant difference.

METHODOLOGY

Institutional ethical committee approval and informed parental consent were

obtained. Sixty (60) American Society of Anesthesiology (ASA) classification I-II

children aged between one (1) to seven (7) years under-going elective day case

herniotomy were studied. This was a randomized study in which the children were

allocated by blind balloting to one of the two groups (Group I, Group II).

Sample size was determined using the following formula:

n= N

1+N(e)2 where n = sample size

N = population size

e = level of precision (10%)

120 = number of paediatric patients who had

day case herniotomy in LUTH in 2008.

n = 120/1 + 120 (0.1)2

= 120/1 + 120 × 0.01

= 120/ 1 +1.2

= 120/ 2.2

= 54.55

= 55.

Sixty (60) was chosen as the sample size for this study.

Exclusion criteria included known hypersensitivity to amide local anaesthetic or

Non-steroidal anti-inflammatory drugs (NSAIDS), active or severe renal, hepatic,

respiratory or cardiac disease, history of seizures, asthma, neuromuscular disorder,

presence of clotting disorder, platelet count less than 100,000/mm3 and parental

refusal to participate in the study.

Routine preoperative fasting 6 hours to solids and 2hours to clear fluid was strictly

adhered to. None of the children was premedicated.

Induction Protocol:

In the operating room Precordial stethoscope (PCS), electrocardiograph (ECG)

leads, blood pressure cuff, pulse oximeter probe were attached to patients.

Inhalational induction was achieved with gradual increment of halothane up to

3.5% in 100% oxygen via Mapleson F breathing system for patients < 25kg or Bain

circuit for patients’ ≥ 25kg with appropriate size face mask. Venous cannulation was

performed on the dorsum of the hand when the depth of anaesthesia was adjudged

adequate by observing the eyes to be centrally placed, loss of conjuctival reflex,

and regular respiration. The airway was maintained with Laryngeal Mask Airway

(LMA) of appropriate size (2 or 2.5) Anaesthesia was maintained with O2 in

isoflurane 1.5-2.5% with patients breathing spontaneously. Following induction of

anaesthesia,

Group I: Received caudal bupivacaine 0.125% (1ml/kg), using a 23guage cannula

under aseptic condition with patient in lateral position.

Group II: Received 1mg/kg diclofenac diluted in 4.3% dextrose in 0.18% saline

10ml/kg and infused over 10 minutes.

Surgery was allowed to proceed immediately after completion of test drug

administration.

Data was collected by the researcher with the assistance of an anaesthetic

Registrar. Data collected included age, gender, weight, surgical procedure and ASA

physical status, duration of surgery (min), duration of anaesthesia (min), time to

recovery (min), time to micturition (min), time to ambulation (min), time to first

analgesia and postoperative pain scores.

Study period started immediately after transfer of patients to the recovery room.

During this time, a nurse blinded to the two groups assessed the pain using

mCHEOPS at 0(arrival in recovery room), 1, 2, 3 and 4 hours and assigned a

numerical value to six behavioural patterns - cry, facial expression, verbalization,

body posture, torso and leg movements (Appendix I). A score of <6 was taken to be

satisfactory pain control while a score of ≥6 as moderate to severe pain and I/V

paracetamol 15mg/kg was given as the rescue analgesia at this point. All patients

that received rescue analgesia at any stage of pain assessment were subsequently

not assessed for pain again.

Parents were instructed on how to assess pain as none, mild, moderate, severe and

rated pain at home for 24 hours after discharge. Oral para-cetamol was given at

home to any child whose pain was rated as moderate to severe (≥6) in ages 4- 7yrs

and those between age 1 and 3yr that refused food and could not be consoled

following crying. The data of total analgesic consumption at home among the two

groups was collected by the researcher.

Data collected was entered onto a proforma (Appendix I) and analyzed with the

Statistical Package for Social Sciences (SPSS® 13 Inc. Chicago Illinois). Data obtained

were subjected to statistical analysis using Student-t test, Chi-square and Fischer’s

test. All parametric data was reported as mean ± standard deviation and all

categorical data as frequencies. A p value of < 0.05 was accepted as statistically

significant.

DEFINITION OF TERMS

For the purpose of this study, these definitions were used.

Duration of Surgery = time from surgical incision to the time wound

dressing was applied.

Duration of Anaesthesia = time from institution of anaesthesia to the time

of discontinuation of anaesthetic.

Duration of Recovery = defined as the time from discontinuation of

anaesthetic to the time of crying and or spontaneous

eye opening.

Time to Micturition = time from institution of analgesia to time of

voiding of urine.

Time to Ambulation = time from institution of analgesia to the time patient

assumed ability to walk or sit without assistance.

Time to Analgesia = refers to time from institution of analgesia to the

time of first rescue analgesia.

Immediate postoperative period= this is the first 4 hour period in the recovery

room beginning at time T0 (time patient arrived in the

recovery room).

Late postoperative period = time from discharge to the first postoperative

day (covering 24hrs post surgery).

RESULTS

Sixty paediatric surgical patients undergoing elective day case herniotomy were

divided in the two groups, group I (Caudal) and group II (Diclofenac) of which each

group had 30 patients.

Table I: shows the demographic data and there is no statistical significant difference

between the two groups. Age range in caudal group was 1-7years with a mean of

4.0± 2.1 years, which was similar to a range of 1-7years and a mean of 4.0± 2.0 in

the diclofenac group.

Mean weight was 15.4± 4.7kg in caudal group and 15.2± 4.6kg in the diclofenac

group, and all patients were in a weight range of 8– 25kg.

The ratio of ASAI to ASAII in the caudal group was 21: 9 while that of the diclofenac

group was 26: 4. Both groups showed male dominance of similar magnitude.

Table I also shows the mean duration of surgery and anaesthesia. The mean

duration of surgical procedure in caudal group was 33.6±19.6 minutes while that

of diclofenac group was 27.0± 4.1 minutes. No significant difference p value of 0.08.

The duration of anaesthesia was significantly different with a p value of 0.0001.

Caudal group showed a mean duration of 63.9± 19.3 minutes, and that of

diclofenac group was 48.7± 5.1 minutes.

Table II shows the comparison of duration of recovery, first rescue analgesia,

micturition, ambulation and discharge. All the events showed significant difference

between the two groups. The time between administration of analgesia to recovery

was 56.7±17.5min in the caudal group and 42.6±3.2min in the diclofenac group

with a p-value of 0.0001.

The mean duration to first rescue analgesia was longer in caudal group (239.3±24.6

minutes) compared to 167.6±43.2 (SEM) min in the diclofenac group (p value =

0.0239).

The mean length of time between analgesia to micturition was significantly shorter

in caudal group (156.5±28.3min) compared to 182.9± 39.5min in the diclofenac

group (p = 0.004).

The mean time of analgesia to ambulation was 186.5± 44.2min in caudal group, but

218.0± 32.4min in diclofenac group (p-value of 0.003).

The time between analgesia to discharge from the recovery room was 270.7±

14.2min (caudal group), while it was 264.2±11.0min in diclofenac group. There was

no statistical significant difference between the two groups, the p-value being 0.05.

Table III shows pain scores at 0, 1, 2, 3 and 4hours which showed statistically

significant difference throughout the early phase of the study.

At 0hr - signifying arrival at the recovery room, the mean pain score for caudal

group was 0.0± 0.0, while that of diclofenac group was 2.7±2.7. This was statistically

significant with a p-value of < 0.0001. Figure 1 shows that all the 30(100%) patients

who had caudal block had a pain score 0 –3 compared with 14 (46.7%) patients in

the diclofenac group. 10 patients (33.3%) in the diclofenac group had pain score of

4–5 and the remaining 6 patients (20%) had a score of ≥6 ( p < 0.0001). These 6

patients were removed from the subsequent pain assessment as they received

rescue analgesia.

At 1hour - The mean value for pain score was still 0.0 ± 0.0 for caudal group while

that of diclofenac group was 3.9± 2.32 (p-value < 0.0001), as shown in Table III.

Figure 2 shows that all the 30 patients (100%) that received caudal block still had a

score of 0-3 (no pain), while 7 patients representing 29.2% of the diclofenac group

recorded a score of 0- 3, 11 patients (45.8%) had a score of 4-5 (mild pain) and 6

patients (25%) experienced moderate to severe pain that required rescue

analgesia, p< 0.0001.

At 2hours - the mean value for pain score was 0.9± 0.34 (SEM) among caudal group

patients and that of diclofenac group was 3.7± 2.2, p-value of <0.001. Fig 3 shows

that in the caudal group, 24 patients (80%) had pain score 0- 3 (no pain) and 6

patients (20%) experienced mild pain (4-5 score) compared with 6 patients (33.3%)

patients with no pain, 6 patients (33.3%) mild pain, and 6 patients (33.3%) had a

score of ≥6 (moderate to severe pain) among those who received diclofenac (p =

0.0006). These 6 patients were removed from subsequent pain assessment as they

received rescue analgesia.

At 3hours of pain assessment in the recovery room, the mean value for pain score

was 4.2± 1.7 in caudal group and 2.6± 2.0 in the diclofenac group (p-value of 0.04).

Fig 4 shows that 4 patients (13.3%) scored 0-3, 25 patients (83.3%) experienced

mild pain and one patient (3.33%) had pain score of ≥6 among the caudal group,

while 7(58.3%) patients of the remaining 18 patients in the diclofenac group, had a

score of 0-3(no pain) and 5 patients (41.66%) experienced mild pain (p = 0.01).

At 4hours of postoperative assessment the mean pain score was 5.7±1.1 in caudal

group, while that of diclofenac group was 1.6 ±0.1 (SEM). Fig 5 shows that 8

patients (66.7%) in diclofenac group had pain score of 0-3 compared with 1 (3.45%)

patient in caudal group. Four (33.3%) patients in the diclofenac had mild pain

compared with 2 in caudal. 26 (89.7%) patients in caudal had score >6, (p< 0.001).

Table IV shows 25 patients (83.33%) in caudal group had oral parace-tamol at home

compared with 16 patients (53.3%) in diclofenac group. This was statistically

significant (p= 0.026).

No complication was observed in any of the two groups.

TABLE I: DEMOGRAPHIC AND CLINICAL CHARACTERISTICS OF PATIENTS.

Group I Group II P- value

(n =30) (n =30)

Age (yrs)

(mean±SD) 4.0± 2.1 4.0± 2.0 0.73

Weight (kg) 15.4± 4.7 15± 4.6 0.77

(mean±SD)

Gender Ratio

(M:F) 30: 0 29:1 0.61

ASA Classification

Ratio ASAI:II 29: 1 26 : 4 0.12

(mean±SD)

Mean duration of

Surgery 33.6± 19.6 27.0± 4.1 0.08

Mean duration of

Anaesthesia 63.9± 19.3 48.7± 5.1 0.0001

Group I = Caudal block, Group II = I/V Diclofenac.

TABLE II: COMPARISON OF DURATION OF RECOVERY, FIRST ANALGESIA,

MICTURITION, AMBULATION AND DISCHARGE

Time Group I Group II p-value

(min) (n=30) (n=30)

Recovery

(Mean±SD) 56.7±17.5 42.6±3.2 0.0001

Analgesia

(Mean±SD) 239±24.6 167.6 (43.2 SEM) 0.0239

Micturition

(Mean±SD) 156.5±28.3 182.9±39.5 0.004

Ambulation

(Mean±SD) 186.5±44.2 218.0±32.4 0.003

Discharge

(Mean±SD) 270.7±14.2 264±11.0 0.05

Group I = Caudal block, Group II = I/V Diclofenac.

Duration in minutes.

Table III: Mean Postoperative pain scores at 0, 1, 2, 3 and 4 hours.

Time (hr)

Group I

(mean ± SD)

Group II

(mean± SD)

P- value

0 0.0 ± 0.0 2.7± 2.7 <0.0001

1

(n=30)

0.0 ± 0.0

(n=30)

3.9 ± 2.3

< 0.0001

2

(n=30)

0.9 ± 1.8

(n=24)

3.7 ± 2.2

0.0006

3

(n=30)

4.2 ± 1.7

(n=18)

2.6 ± 2.0

0.01

4

(n=30)

5.7 ± 1.1

(n=12)

1.6 ± 2.1

< 0.0001

(n=29) (n=12)

Group I = Caudal block, Group II = I/V Diclofenac.

Table IV: Dose per weight, number of patients that received

analgesic and postoperative complications at home.

Group I

(n =30)

Diclofenac P-value

(n =30)

Oral Paracetamol

(20ml/kg)

25 (83.33%)

16 (53.33%) 0.026

Limb weakness

0 (nil) 0 (nil)

Vomiting

0 0

Sleeplessness

0 0

Refusal of feeds

0 0

Bleeding 0 0

Group I = Caudal block, Group II = I/V Diclofenac

Figure 1: Distribution of pain scored at 0hour.

Fig. 1 Distribution of Pain Score at 0 hour

30

0 0

14

10

6

0

5

10

15

20

25

30

35

No Pain (0-3) Mild Pain (4-5) Moderate/ Severe pain (>6)

Pain Score

Nu

mb

er

of

Pati

en

ts

Caudal

Diclofenac

Fig 2. Distribution of Pain score at 1 hour

30

0 0

7

11

6

0

5

10

15

20

25

30

35

No Pain (0-3) Mild Pain (4-5) Moderate/ Severe pain (>6)

Pain Score

Nu

mb

er

of

Pati

en

ts

Caudal

Diclofenac

fig 3. Distribution of pain score at 2 hours

24

6

0

6 6 6

0

5

10

15

20

25

30

No Pain (0-3) Mild Pain (4-5) Moderate/ Severe pain (>6)

Pain Score

Nu

mb

er

of

pati

en

ts

Caudal

Diclofenac

Fig 4.Distribution of Pain Score at 3 hours

4

24

1

7

5

00

5

10

15

20

25

30

No Pain (0-3) Mild Pain (4-5) Moderate/ Severe pain (>6)

Pain Score

Nu

mb

er

of

Pati

en

ts

Caudal

Diclofenac

ig 5. Distribution of Pain Score at 4 hours

12

26

8

4

00

5

10

15

20

25

30

No Pain (0-3) Mild Pain (4-5) Moderate/ Severe pain (>6)

Pain Score

Nu

mb

er

of

ati

en

ts

Caudal

Diclofenac

DISCUSSION

The result of this study indicated that caudal bupivacaine 0.125% (1ml/kg) provided

better pain control in the early postoperative period than I/V diclofenac but the

reverse is the case in the late postoperative period.

The investigation of pain is of tremendous clinical importance but very complex and

difficult due to its subjective nature. Freedom from post operative pain is the

central concern of surgical patients, and alleviation of the pain may contribute

significantly to improve clinical outcomes.

Children experience pain differently than adults do. Their emotional development,

previous experiences, and ability to communicate and understand are difficult

variables to measure.

Although several methods to prevent and safely and effectively treat post-

operative pain exist, it is known that they are not being used and that paediatric

pain is still under-estimated and neglected by medicine and nursing teams.69 The

reduction of post herniorrhaphy pain is not only important for the patients comfort,

but also reducing pain inhibits trauma induced nociceptive impulses that induce

autonomic and somatic reflex responses to pain.

Caudal anaesthesia with bupivacaine and light general anaesthesia provides an

excellent intraoperative and postoperative analgesia in children undergoing

genitourinary procedures.

All the 30 patients (100%) in the caudal group were free from any form of pain on

arrival at the recovery room and also at first hour of evaluation, while 6 patients

(20%) experienced mild pain during the second hour of pain assessment. The mean

pain scores were 0±0 and 0.9±1.8 respectively. Only one of the patients (3.3%) in

the caudal group experienced moderate to severe pain (pain score ≥6) in the third

hour postoperatively. In comparison with the diclofenac group, 14 patients (46.7%)

experienced no pain, 10 patients (33.3%) had mild pain while 6 (20%) had moderate

to severe pain on arrival in the recovery room. The same trends of observations

were recorded after 1hour and 2hours of pain assessment (mean pain score being

2.7±2.7, 3.9±2.3, 3.7±2.2). All the 18 patients with pain score ≥6 (6 patients at every

assessment) who had rescue analgesia (I/V paracetamol 15mg/kg) were removed

from further pain assessment.

The mean duration to first analgesia was 239±24.6 minutes in the caudal group as

against 167.6± 43.2(SEM) minutes in the diclofenac group (p-value of 0.024). This

was similar to the finding of Ivani55 who recorded a time of 233.2±28minutes for

caudal bupivacaine.

The mean duration to first analgesia recorded in this study for the caudal group,

was shorter than what Edomwonyi et al58 obtained (7.34± 5.2hr) in their study

using a higher concentration (0.25%) of bupivacaine. It is a well known fact that

the variables determining the quality and level of caudal block are the volume, dose

and concentration of the injected drug. In contrast to the above, Verghese et al53

observed that the use of a larger volume of diluted bupivacaine for caudal block

produced a significantly more effective block than a smaller volume of standard

0.25% solution. Addition of epinephrine and sodium bicarbonate to bupivacaine by

Verghese et al in their study made the duration of the block longer than what was

obtained in the present study. Epinephrine (or adrenaline) is a vasoconstrictor,

which when added to local anaesthetics, decreases the rate of absorption of the

local anaesthetics thereby prolonging the duration of action of the local

anaesthetics. Also addition of sodium bicarbonate to local anaesthetic is for rapid

onset of action.70

The mean duration to first analgesia or otherwise duration of analgesia (167.6±43.2

SEM) in the diclofenac group as observed in this study was rather too short. Also

the duration of anaesthesia observed in this group (48.7±5.1min) was significantly

shorter than the caudal group (63.9±19.3min), it could be said that the short

duration to first analgesia in this group (diclofenac) was due to the fact that

sufficient time was not allowed in this present study for the effect of diclofenac to

peak. This factor was suggested by Desjardins et al71 who observed in a study that

laparoscopic surgical pain peaked within 2-4 hours, hence giving diclofenac sodium

which has a half- life of 2hours would greatly reduce the intensity of pain in the

immediate postoperative period. A similar recommendation was made by Mehta

et al72 that patients who received diclofenac 2 hours before surgery had

significantly lower incidence of pain during immediate early postoperative period.

This was not observed in this study due to time constraint as the patients were day

cases and other logistics that are beyond the capacity of the investigator.

There were significant differences in mean pain scores in all the time intervals

studied. There was a sharp drop in the number of patients who experienced mild

pain from 24 (80%) at 2hrs, to 4(13.3%) at 3hrs and 1(3.3%) at 4hrs in patients who

had caudal block but an improvement in pain management from 6(33.3%) to

7(58.3%) and 8(66.7%) was witnessed in the patients who received diclofenac at

2hrs, 3hrs,and 4hrs respectively.

Modified Children Hospital of Eastern Ontario Pain Score (mCHEOPS) was used to

assess the postoperative pain. This is to circumvent the potential difficulties of

communicating pain inherent in paediatric self reporting scale and also to

distinguish between behaviour due to pain and other types of distress like hunger,

fear or anxiety. The validity and reliability of this Behavioural Observational Pain

Scale for postoperative pain measurement in age 1–7years had been

demonstrated.73

Inguinal hernia is one of the most common paediatric surgical problems in this

environment. Surgery is often indicated to decrease complications like intestinal

obstruction and strangulation that could result from it. The most common method

of providing postoperative analgesia is systemic administration of narcotic

analgesics though these drugs have their side effects. Caudal block used in this

present study provided both intraoperative and postoperative analgesia; all the

children that received caudal bupivacaine were free from pain in the early hours of

pain assessment.

Other suggested benefits of caudal bupivacaine also experienced in this study,

include decreased intraoperative requirement for general anaesthetics, and less

need for the use of parenteral opioids, thereby limiting the incidence of respiratory

depression and stress hormone response.74 Caudal block using local anaesthetics in

children has become an integral part of anaesthetic management and is very

adequate for both intra and postoperative analgesia as many studies have shown

satisfactory results.57,66,67 Edomwonyi et al58 assessed children who had caudal

block (0.25%) versus local infiltration and found that there was no statistically

significant difference between the two techniques in regards to postoperative pain

management.

The use of NSAIDs for paediatric analgesia has become an extremely popular

method or technique as they are effective with few side effects and produce an

opioid sparing action through decreasing the inflammatory mediators generated at

the site of tissue injury. However, diclofenac like other NSAIDs should not be used

in paediatric patients with a weight less than 10kg, age less than 1 year and other

contraindications like asthma, renal impairment, hypovolaemia, bleeding

disorder75. Studies with this drug (diclofenac) have not been able to show its

efficacy as a single drug.49,51 This supports the finding of this study in which 6

patients (20%) experienced moderate to severe pain with a score of ≥6 at 0hour,

1hour and 2hours of assessment. The early pain experienced in this study was in

contrast to the study of Campell76 where I/V diclofenac produced lower incidence

of pain during the immediate postoperative period. The reason for this was that

the drug was administered 30 minutes before surgical incision, which was not

applied in this current study rather the drug was given over 10 minutes before

surgical stimulation of patients that received diclofenac. As the onset of action of

I/V diclofenac is 10-15minutes this may have been the reason why patients still

experienced moderate to severe pain after its administration. Also the differences

in method of pain scoring and calculation of duration of analgesia could have

contributed to this discrepancy.

The mean recovery time for diclofenac group was 42.6±3.2min while that of caudal

group was 56.7± 17.5min. The children in the diclofenac group woke-up faster and

screamed at recovery. This observation was similar to that made by Faponle et al77

in a retrospective based questionnaire given to parents of children who had day

case surgery. They noted that a child with severe pain would awake sooner and

would have poor quality recovery. But in a review article by Romsing and

collaegue78, diclofenac was associated significantly with rapid return to calm and

wakefulness when compared with papaveretum in 60 children who had

tonsillectomy. Romsing78 did not specify the time diclofenac was given. On the

other hand, it was observed in this present study that all the patients that had

caudal block were calm and free from postoperative agitation. Similar observation

was made by Aouad et al79. This is likely due to the excellent analgesia produced by

caudal bupivacaine.

Caudal block and I/V diclofenac were given to the patients before surgical incision.

The patients who received caudal block were free from pain in the early hours of

the postoperative period while those who had I/V diclofenac experienced better

pain relief in the late postoperative period. This was similar to the findings in other

studies by Ryhänen et al66 where I/M and rectal diclofenac were compared with

caudal block using 0.25% bupivacaine for post operative pain control in children

who had herniotomy and hypospadias surgery. Onset of action was in favour of

caudal bupivacaine group whereas long duration of analgesia was in favour of the

diclofenac group.

The use of single shot caudal bupivacaine 0.125% (1ml/kg) in this study was found

to be effective. Assessment of pain with mCHEOPS showed good analgesic effects.

Only one patient of the caudal group experienced pain with a score of ≥ 6 in the

first 3hr of assessment and this received rescue analgesia. Although caudal block

is a versatile technique for intraoperative and postoperative analgesia, the major

limitation of the single shot technique is the relatively short duration of

postoperative analgesia. To further prolong postoperative analgesia following

caudal is to add different adjuncts to the local anaesthetic. Klimsiha et al80

compared the efficacy of clonidine and ketamine added to bupivacaine versus

bupivacaine alone. They found that the combination of bupivacaine and ketamine

produced a longer duration of analgesia (12.5hrs) when compared with clonidine

and bupivacaine (5.8hrs) and bupivacaine alone 3.2hrs.

A single dose of intravenous diclofenac (1ml/kg) was found to be ineffective for

postoperative pain in the first 2hrs of assessment but there was a remarkable

improvement in its efficacy afterwards. Diclofenac is known to have a peak effect

at 2hr which may have accounted for this observation. Good analgesia was

observed from the 3rd hour of postoperative pain assessment. This was reflected

by the reduction in the total analgesic consumption of oral Paracetamol given at

home among the patients in this group (Table IV). This observation in this study was

similar to that of Borker.68

The use of regional anaesthesia as an adjunct to light general anaesthesia provided

special advantage for children undergoing surgery as outpatients, in whom this

technique was associated with earlier ambulation and discharge. In this study the

time to ambulation in the caudal group was 186.5± 44.2min which was significantly

different from that of diclofenac 218.0±32.4min. The time to ambulation was

shorter in the caudal group probably due to effective pain control. Edomwonyi et

al58 recorded 2.17± 0.867hr which was similar to the value obtained in this study,

though higher concentration of bupivacaine (0.25%) was used in their study. This

thereby suggests that the ability to ambulate may be related to the absence of pain

provided motor block does not exist.

Time to discharge in this study was 270.7± 14.2 for the caudal group while that of

the diclofenac group was 264.2± 11.0min. This was not statistically significant. Rice

and colleague81 observed a different time of discharge of 179± 88min when they

investigated pre and post-surgical insertion of caudal block. Caudal was placed

prior to the start of surgery in one group and post surgery in the other group. In

their study Rice et al81 concluded that the duration of postoperative analgesia is

not impaired by placing the caudal block prior to the start of a brief surgical

procedure compared to placement at the end of surgery. This was due to the fact

that no statistically significant differences were observed in the two groups with

regard to their postoperative pain, the need for analgesia, and discharge time.

Rice81 did not mention whether another analgesic was provided intraoperatively in

the group that had post surgical caudal block.

Time to micturition was 156.5± 28.3min in the caudal group while it was 182.9±

39.5min in the diclofenac group, (p-value of 0.004). This could be due to long

abstinence from fluid and long preoperative fasting. Also the long time to

micturition in this study is principally associated with mode of action of diclofenac.

It inhibits cyclo-oxygenase enzymes, resulting in decreased synthesis of eicosanoids

which are important autocoids in the regulation of renal function. This has been

implicated for the renal dysfunction associated with NSAIDs.82

Edomwonyi et al58 observed a significantly longer time of 4.02(1.69) hr to

micturition and some of the patients experienced urinary retention. The reason for

this difference could be due to the concentration of bupivacaine (0.25%) used in

their study. In caudal block, urinary retention is produced as a result of

sympathectomy caused by the local anaesthetic. The bladder is under the control

of autonomic nervous (parasympathetic and sympathetic nervous) system.

Parasympathetic supply to the bladder and internal sphincter of the bladder causes

contraction while the sympathetic supply causes relaxation. The unopposed action

of parasympathetic as a result of sympathectomy during spinal anaesthesia is

responsible for the urinary retention with this technique.83

Also in this study, a statistically significant difference was found between the two

groups in the point of pain score. Caudal bupivacaine provided more pain free

patients in the immediate postoperative period. Despite the early and better pain

relief in the caudal group a good percentage of the diclofenac group (53.3%) had

no pain and the remaining 46.7% experienced mild pain in the early part of the

study compared to 89.7% of caudal group who experienced moderate to severe

pain at the end of 4hr assessment in the recovery room. This sharp drop in pain

relief in the caudal group after 3hr could be as a result of the concentration of

bupivacaine (0.125%) used in this study.

The caudal bupivacaine group recorded higher consumption of analgesia than the

diclofenac group at the end of this study (first day postoperative). Twenty-five

patients (83.3%) that had caudal block required oral Paracetamol at home

compared with 16 patients (53.3%) that received I/V diclofenac. Borker68 observed

12% request for analgesia in caudal block compared with 20% in the diclofenac

group. The differences could be attributed to routes of administration of

diclofenac. Intravenous route was used in this study while Borker used rectal route.

The rectal route of administration is associated with erratic absorption due to

presence of faeces in the rectum. Also rectal administration of drug may stimulate

bowel movement, and the drug may be passed out with faeces.

No adverse or any untoward reaction was observed in this study both in the

immediate and late postoperative period.

CONCLUSION

This study shows that caudal bupivacaine provided early and good postoperative

pain relief compared with I/V diclofenac in the first 3hours after administration but

i/v diclofenac decreased pain and analgesic requirement in the latter part of the

postoperative period due to its long duration of action.

Regional techniques still stand out as the best option of relieving both

intraoperative and postoperative pain.

Combination of these two methods for perioperative pain management will

provide a balanced and complimentary form of pain relief based on

pharmacokinetics.

RECOMMENDATIONS

There is need for appropriate plan for postoperative pain relief in all surgical

patients. The fact that it has been recognised that pain treatment is a basic human

right, adequate postoperative pain management can also fast-track patient

discharge from health facility and reduce morbidity and mortality associated with

under-treatment of surgical trauma. It is therefore recommended that:

1) Systemic analgesic can be combined with any of the regional techniques

to produce complimentary and synergistic effects in postoperative pain

management. A combination of local anaesthetic and non-opioid analgesics

should be encouraged in day-case procedures.

2) Analgesics should be prescribed and based on their pharmacokinetic profile

in order to ensure adequate postoperative analgesia.

3) Education and motivation of different staff groups to assess and treat pain

according to local protocols must be put in place for effective postoperative

pain management. Pain assessment should become as basic as measuring

pulse rate and blood pressure. Pain assessment tool must be simple to use

and understand by the nurses. Pain measurement can be adapted to local

circumstances.

4) Public enlightenment campaign should be under-taken by health care

providers to educate the people on the adverse effects of pain.

5) There should be access to simple, effective and safe analgesics in all the

health institutions for pain management.

LIMITATIONS

This study has its limitations. The period of effective pain assessment was only 4

hours of stay in the hospital. The remaining 20 hours in which the parents were

responsible could not be fool-proof because of the short interval of explaining to

the parents how to assess their children’s pain at home.

There was problem of collecting information from some of the parents who gave

the telephone number of their spouse (husband).

There could be observer variations in the pain score as this was recorded by two

different nurses.

Another limitation is that the pain assessment tools used in the study was

subjective.

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APPENDIX

INVITATION TO PARTICIPATE:- TEMPLATE FOR COMPLETION BY RESEARCHER.

COMPARISON OF CAUDAL ANALGESIA AND IV DICLOFENAC FOR

POSTOPERATIVE PAIN RELIEF IN PAEDIATRIC PATIENTS.

This is to invite you to take part in a research study, which I think may be important.

The information which follows will tell you about the study. It is important that you

understand what is in the leaflet. It says what will happen to your child if you want

him/her to take part. Whether your child takes part or not is entirely your choice.

Please ask any questions you want to about the research and I will try my best to

answer them.

Summary of Study: This will be explained to all the parents in a language clearly

understand and best spoken by them.

Your child will be undergoing an operation under general anaesthesia (sleep) either

by breathing a mixture of gases (halothane/oxygen) or by an intravenous injection

of a drug called propofol. Once asleep a tube called laryngeal mask airway (LMA)

will be placed through your child’s mouth to the opening of the wind pipe. This

enables the child to breath well without compromise during the operation. After

this, your child will be given an injection of local anaesthetic (bupivacaine) through

a hole (sacral hiatus) at the upper part of the buttock. Alternatively your child will

be given an intravenous injection (diclofenac) through infusion of 100ml of 4.3%

dextrose in 0.18% saline over 10minutes.

What are our aims?

The aim of our study is to compare the postoperative analgesic efficacy of caudal

block using bupivacaine 0.125%) with diclofenac (1ml/kg).

How will the study be done?

Children who take part in the study will be put into two groups. The first group will

receive caudal block(0.125% bupivacaine) while the second group will be given i/v

diclofenac(1ml/kg) infusion. All children in the study will have standard care by the

medical and nursing staff as usual.

What you need to do?

All parents/guardians in the study will be asked to fill in some forms. Those who

are unable to write will be assisted to fill the form. We will also write some details

about your child’s anaesthetic and operations and which study group he/she

belongs to. These records will be confidential and only seen by doctors and nurses

involved in the study.

Benefits/Disadvantages

The benefit of this study to you and your child is that pain after your child’s

operation will be markedly reduced. Also the frequency of interventional analgesia

will be less.

There are few but rare risks associated with these techniques under investigation.

These are weakness of the limbs (lower), urinary retention, dural puncture,

bronchospasm and bleeding.

Please let the researcher know if your child has any history of allergy to bupivacaine

or non-steroidal anti-inflammatory drugs (NSAIDs) or bleeding disorder, asthma –

that may mean they cannot take part in this study.

If you have any questions about this study, you can contact Dr. B.K. Aroso directly

or through the department of Anaesthesia. You don’t have to join in the study. You

are free to decide for your child not to be in this study.

What happens if you are worried or there is an emergency? You will always be able

to contact the researcher to discuss your concerns and/or to get help.

Name – Dr. Aroso, Bunmi Kunle

Address – Department of Anaesthesia,

Lagos University Teaching Hospital,

Idi-Araba, Lagos.

Telephone No – 08062892088.

Please address any question that you may have about the study to this researcher.

Please be assured that this study has been approved by the Ethical Committee of

the Lagos University Teaching Hospital as being safe.

WRITTEN CONSENT FORM:

Comparison of caudal analgesia and iv diclofenac for postoperative pain control for

herniotomy among Nigerian children aged 1- 7years.

The researcher has invited me to take part in this research.

I understand that this leaflet contains information about the research. I have

a copy of the leaflet to keep.

I have had the chance to talk and ask questions about the study.

I know what my part will be in the study and I know how long it will take.

I know how the study may affect me. I have been told if there are possible

risks or complications to report at LUTH immediately.

I know that the Lagos University Teaching Hospital Research Ethics

Committee has agreed to this study.

I understand that personal information is strictly confidential: I know the only

people who may see the information about my part in this study are the

research team.

I understand that my personal information may be stored on a computer. If

this is done, it will not affect confidentiality of this information.

I freely consent to be a subject in the study. No one has put pressure on me.

I know that I can stop taking part in the study any time.

I know if I do not take part I will still be able to have normal treatment.

I know that if there are any problems, I can contact:

Dr. Bunmi K. Aroso

Anaesthesia Department, LUTH.

Tel. 08062892088.

Patient’s Signature: ----------------------------

Witness Name: ----------------------------

Witness Signature: ----------------------------

Date: ----------------------------

COMPARISON OF CAUDAL ANALGESIA AND

INTRAVENOUS DICLOFENAC FOR

POSTOPERATIVE PAIN RELIEF IN PAEDIATRIC

PATIENTS

A DISSERTATION

BY

DR AROSO BUNMI KUNLE

MBBS (MAIDUGURI), DA (LAGOS)

SUBMITTED IN PARTIAL FULFILLMENT OF THE

REQUIREMENT FOR THE AWARD OF THE FELLOWSHIP

OF THE FACULTY OF ANAESTHESIA, NATIONAL POSTGRADUATE MEDICAL COLLEGE OF NIGERIA

MAY 2010.

TABLE OF CONTENTS

Page

TITLE i

TABLE OF CONTENTS ii

DECLARATION iv

CERTIFICATION v

DEDICATION vi

ACKNOWLEDGEMENT vii

LIST OF ABBREVIATIONS viii

LIST OF TABLES ix

LIST OF FIGURES x

LIST OF APPENDICES xi

SUMMARY 1

INTRODUCTION 3

AIMS AND OBJECTIVES 6

LITERATURE REVIEW 7

METHODOLOGY 32

DEFINITION OF TERMS 36

RESULTS 37

TABLES AND FIGURES 42

DISCUSSION 50

CONCLUSION 63

RECOMMENDATIONS 64

LIMITATIONS 66

REFERENCES 67

APPENDICES 82

DECLARATION

I, AROSO BUNMI KUNLE hereby declare that the contents of this dissertation are

the results of the work done by me at the Lagos University Teaching Hospital, Lagos,

Nigeria. The work has not been presented for any publication, examination or for

fellowship award.

-----------------------------------------------------

DR.AROSO, BUNMI KUNLE.

CERTIFICATION

THE CERTIFICATION THAT ATTESTS TO THE WORK DONE BY DR.AROSO BUNMI

KUNLE ACCOMPANIES THIS BOOK.

WE SUPERVISED THE WRITING OF THIS BOOK.

1. SIGNATURE/DATE ------------------------------------------

NAME - PROF O.T. KUSHIMO

STATUS – HEAD OF DEPARTMENT

DEPARTENT OF ANAESTHESIA

LUTH.

LAGOS, NIGERIA.

2. SIGNATURE/DATE -------------------------------------------

NAME – DR. I. IDESALU

STATUS – SENIOR LECTURER

DEPARTMENT OF ANAESTHESIA

LUTH

LAGOS, NIGERIA

3. SIGNATURE/DATE --------------------------------------------

NAME – DR. TOLA OLATOSI

STATUS- LECTURER

DEPARTMENT OF ANAESTHESIA

LUTH

LAGOS, NIGERIA

DEDICATION

This work is dedicated to the surgical paediatric patients who suffered pain because

of wrong notion that children don’t feel pain, my darling wife Olufunke for her love,

encouragement, support and understanding, our lovely children for enduring all

things during the years of residency training, and above all to God Almighty for His

sustaining power. TO GOD BE THE GLORY.

ACKNOWLEDGEMENT

I wish to express my sincere appreciation and profound gratitude to the following

special people for their contributions to this work.

Prof O.T. Kushimo, Consultant/Professor of Anaesthesia and Head of Department

of Anaesthesia, Lagos University Teaching Hospital, for her encouragement,

patience as well as valuable suggestions and supervision in the writing of this book.

Dr I. Desalu, Consultant/ Senior Lecturer, Department of Anaesthesia, Lagos

University Teaching Hospital for painstakingly going through this work. I am

grateful for your corrections, suggestions and supervision of this book.

Dr Tola Olatosi, Consultant/Lecturer Department Anaesthesia, Lagos University

Teaching Hospital. Thanks for the attention, correction and supervision of this

work.

I should not forget Prof Amanor-Boadu, UCH Ibadan who prompted the idea of

doing a study in children.

I will also like to appreciate Drs Dada and Akanmu, Consultants/Lecturers,

Department of Anaesthesia for their support and encouragement.

My appreciation goes to the recovery room nurses Principal Nursing Officers

Tinubu and Daramola who assessed the children postoperatively.

Finally, I express my appreciation to the entire Anaesthesia Department for their

support through out the period of this study. May the Almighty God bless you all in

Jesus name, Amen.

LIST OF ABBREVIATIONS

APS Acute Pain Service

ASA American Society of Anesthesiologists

BP Blood Pressure

CAS Colour Analogue Scale

CHEOPS Children Hospital of Eastern Ontario Pain Scale

COX Cycloxygenase

ECG Electrocardiography

FiO2 Fractional inspired Oxygen

FLACC Face, Legs, Activity, Cry, Consolability

I/M Intramuscular

I/V Intravenous

Kg Kilogramme

LAs Local anaesthetics

LMA Laryngeal Mask Airway

mCHEOPS modified Children Hospital of Eastern Ontario

Pain Scale

ml/kg Millilitre per kilogramme

mg Milligram

NIBP Non Invasive Blood Pressure

NMDA N- methyl- D- Aspartate

NRS Numerical Rating Scale

NSAIDs Non Steroidal Anti-inflammatory Drugs

OPS Objective Pain Score

PCS Precordial Stethetoscope

PG Prostaglandin

SEM Standard Error of Mean

SpO2 Saturation pressure of Oxygen

SPSS Statistical Package for the Social Sciences

TPPPS Toddler Preschool Postoperative Pain Scale

VAS Visual Analogue Scale

< Less than

≥ Greater than or equal to

LIST OF TABLES

Table I: Demographic and clinical characteristics of patients. 42

Table II: Comparison of duration of recovery, first analgesia,

micturition, ambulation and discharge 43

Table III: Mean Postoperative pain scores at 0, 1, 2, 3

and 4 hours 44

Table IV: Total Analgesic consumption and postoperative

complications at home 45

LIST OF FIGURES

Figure 1: Distribution of pain scored at 0 hour 46

Figure 2: Distribution of pain scores at 1hour postoperative 47

Figure 3: Distribution of Pain score at 2 hours 48

Figure 4: Distribution of Pain score at 3 hours 49

Figure 5: Distribution of Pain score at 4 hours 50

LIST OF APPENDICES

1. APPENDIX I Research Proforma.

2. APPENDIX II Patients informed consent form.

3. APPENDIX III Approval letter of Ethical

Committee of Lagos University Teaching Hospital.

4. APPENDIX IV Approval of Research Proposal by the National

Postgraduate Medical College of Nigeria.