PRE-ANAESTHETIC

CHECKUP AND

PREMEDICATION

Dr. Archana Vaidya,Lecturer,

Dept. of Anaesthesia,GMCH, Nagpur

INTRODUCTION

The role of anesthesiologist is that of consultant to surgeon in

reference to pharmacology & physiology, as in O.T. he is supposed to

manage physiological dysfunction, pharmacological needs & medical

complications.

For this reason he should know the patient in detail.

GOAL OF PREOPERATIVE MEDICAL ASSESSMENT:

1. To reduce the morbidity of surgery.

2. To increase the quality & decrease cost of perioperative care.

3. To return the pt to desirable function as quickly as possible.

Anaesthetist’s visit prior to surgery helps in allaying

patient’s fear about anesthesia and surgery.

He explains the plan of anesthesia whether regional or

general & perioperative care (depending on the type

of surgery).

Still inadequate preop evaluation is one of the top

three causes of lawsuit against anesthesiologist.

-

HISTORY TAKING:

1. H/O Presenting complaints

• H/O cough with / without expectoration

• H/O cold,fever

• H/O breathlessness , chest pain , palpitations

• History of recent medical care, medication or allergies include type of drug, dose & it’s frequency.

2. Surgical history- previous operations, type of anesthesia, any problem with it. Any family member with anesthesia problem.

3. Allergic history

Eg. – Pt. Having allergy to sulfa drug may have allergic reaction to thiopentone.

4. History of addiction Smoking : quantity in packs per day and duration of

smoking. Deleterious effects of smoking

i) Vascular disease of peripheral, coronary & cerebral circulation.

ii) Chronic bronchitis

iii) Carcinoma of lung, oesophagus, stomach, urinary bladder.

-Advised to stop smoking before surgery minimum about 6 weeks.

BENEFICIAL EFFECT OF CESSATION OF SMOKING PRIOR TO SURGERY:

12-24 hours COHb & Nicotine levels

48-72 hours COHb normalise & ciliary function improving.

1-2 Wk’s Sputum production decreases

4-6 Wk’s PFT’s improve if deranged

6-8 Wk’s immune fun & drug metabolism normalise

8-12 Wk’s Overall postop morbidity

b) Alcohol:- Leads to induction of liver enzymes & tolerance to anesthetic drug.

c) Tobacco use.

5. Menstrual & obstetric history in female patients

SYSTEMIC ASSESSMENTI) CARDIOVASCULAR DISEASES :

Cardiovascular reserve : Ask about maximum distance pt. can walk, greatest no. of floor can climb without need to stop.

Recent / past myocardial infarction.

Chest pain, chest heaviness, chest tightness.

H/o swelling over ankles.

Shortness of breath.

H/o high BP or medication to prevent high BP.

H/o use of more than one pillow for sleep at night.

RESPIRATORY AND AIRWAY PROBLEMS :

-Enquire about upper resp. tract infection – as acute URTI lead to bronchospasm, laryngospasm, secretions.

-Adequate mouth opening, loose teeth, denturesHEPATIC & GI DISEASES

•Hepatic diseases contribute to abnormal clotting &

pharmacokinetic.

•GI disease increases risk for aspiration – gastroparesis associated

solid food in stomach & IBD with arthritis in the neck.

•H/o hepatitis,jaundice, liver diseases, malaria

•H/o change in bowel habit

BLEEDING PROBLEMS

H/o blood transfusion & its complication.

Family history of serious bleeding problem.

H/o of bleeding from cuts nose bleeds, minor bruises, tooth

extractions or surgery.

NEUROLOGICAL DISASES

H/o convulsion, stroke, paralysis.

H/o numbness, tingling, sensation in arm or leg.

H/o taking antidepressant, anticonvulsant, sedative.

MUSCULOSKELETAL DISEASES

H/o Arthritis, low back pain, pain pills.

RENAL DISEASES

Produces anaemia, electrolyte disturbances, abnormality in

drug metabolism and excretion.

H/o adequate urine output.

ENDOCRINE DISTURBANCES

H/o polyuria, polydipsia

H/o recurrent headache, sweating, flushing of face.

H/o cold / warm in tolerance, muscle cramps in legs to rule out

thyroid disorders.

SENSITIVE AREAS

concern with pregnancy & possibility of pregnancy in minor, haemoglobinopathy, potential for AIDS.

H/o exposure to blood, semen, urine or saliva of any one likely to have AIDS

High risk groups for AIDS – bi sexual, homosexual, sex with prostitutes within last 18 yrs.

PHYSICAL EXAMINATION

Detailed examination of CVS, RS & airway is important.

Vital signs noted properly.

- Pulse : Rate, Rhythm, Volume, Peripheral pulse, condition of vessel wall, presence of collapsing pulse.

- Blood pressure : from both hands with proper size cuff.

- Temperature : Core body temp.

Respiratory rate & Pattern.

Jugular venous pressure : Normal 3-4 cm

Elevated – Rt heart failure, tricuspid stenosis, cardiac tamponade

Nails & eyes - Pallor, cyanosis, icterus, clubbing.

State of nutrition : malnourished or obese.

Presence or absence of lymph node enlargement.

• EXAMINATION OF RESPIRATORY SYSTEM

• EXAMINATION OF CARDIOVASCULAR SYSTEM

• EXAMINATION OF ABDOMEN

• EXAMINATION OF CENTRAL NERVOUS SYSTEM

• EXAMINATION OF SPINE- for abnormality or

infection.

MAJOR CRITERIA

- Orthopnea

- Paroxysmal nocturnal dyspnea.

- Neck vein distension.

- Basal rales.

- Cardiomegaly

- Acute pul oedema.

- S3 gallop.

- JVP increased.

- Hepatojugular reflex.

SIGNS OF CCF

- MINOR CRITERIA

- Ankle oedema.

- night cough.

- hepatomegaly.

- exertional dyspnea.

- tachycardia.

EXAMINATION OF AIRWAY :

- Should be done properly to avoid airway obstruction & detect difficult intubation.

- Methods to detect difficult airway

1. Distance between – From inside chin & hyoid bone at least 2 finger breadth.

2. Mallampati Classification :

This is determined by asking the patient to sit in front of anestesiologist and asking him to open the mouth widely with tongue protruding.

Grades

I

II

III

IV

Structures to be visualized

Post pharyngeal wall, uvula, faucial piller, soft palate, hard palate

Faucial pillers & soft palate, hard palate.

Soft palate

Only hard palate. (Samson’s Young Modifications)

3. Thyromental Distance : Distance between thyroid notch & tip of jaw.

<6 cm Difficult Airway.

LABORATORY INVESTIGATIONS :

Routine :

1. Hemoglobin or haematocrit

2. Urine – albumin ,sugar, ketones

3. Blood group

Special : Blood Urea Nitrogen & S. creatinine LFT chest X-ray Electrocardiogram Blood Sugar Level Estimation Coagulation test (PT, PTT) Sickle status PFT 2D Echocardiogrami

ASA PHYSICAL STATUS CLASSIFICATION In 1961, ASA adopted physical status classification system of assessing a pt preopatively, co-relate with periop mortality rate.

CLASS

1.

2.

3.

4.

5

6

E

DEFINITION

A normal healthy pt.

A pt with mild systemic disease no functional limitation.

Moderate to severe systemic disease with some fictional limitation.

Severe systemic diseases that is constant threat to life functionally incapacitated.

A moribund pt who is not expected to survive 24 hrs with /without surgery.

Brain dead for organ harvested

If procedure is emergency.

PEDIATRIC AIRWAY EVALUATION :

-Pediatric airway differ from adult airway

- Have large head and tongue.

- Narrow nasal passage

- Anterior and Cephald larynx

- Long epiglottis, short trachea & neck.

- Nasal breathers untill abt 5 yrs.

- Cricoid cartilage (Subglottis) narrowest part.

- Chances of accidental extubation more common with head movements.

Note : in pediatric patients H/o immunization.

PEROP MEDICATION INSTRUCTION GUIDE LINE –

1.medication to be continued on day of Surgery.

anti hypertensive

diuretics

cardiac medication (digoxin)

antidepressant – antianxiety

thyroid, asthma medication

steroids (oral & inhaled)

2. Discontinue 7 days before: aspirin

3. NSAIDS – discontinue 48 hrs before plastic retinal surgery.

4. Oral hypoglycemic drugs discontinue on day of surgery.

5. Insulin – 1/3 dose in morning

6. Warfarin – discontinue 4 days before Sx.

7. Heparin – 4 – 6 hrs before surgery.

8. MAO Inhibitors – 2 weeks before surgery.

PREOPERATING FASTING

Risk of Hypoglycemia & dehydration in prolonged fasting.

Should be minimum 4 hrs for clear fluids and milk.

6 hrs for solid food.

To prevent regurgitation and aspiration.

INFORMED CONSENT

- Obtained from all pt

- Invalid if taken after pre medication

- Of parents or guardian in < 18 yrs & mentally ill pt.

- If parent or guardian not contacted from district medical officer in

emergency.

-Administration of various drugs beforeAdministration of various drugs before

induction of anaesthesia.induction of anaesthesia.

AIMS OF PREMEDICATION AIMS OF PREMEDICATION :

• To allay pre-operative fear and anxiety.

• To produce amnesia and analgesia.

• To reduce secretion from salivary glands and respiratory tract.

• To potentiate anaesthetic drugs

• To depress unwanted reflex vagal activities

• To reduce the pH and volume of gastric contents and risk associated with regurgitation and aspiration.

• To attenuate sympathetic reflex activities and stress associated with anaesthesia and surgery.

• To reduce incidence of post operative nausea and vomiting.

DrugDrug Dose Dose AdvantageAdvantage DisadvatageDisadvatage

MorphineMorphine

0.1 – 0.2 mg/kg 0.1 – 0.2 mg/kg IMIM

10 – 15 mg IM in 10 – 15 mg IM in adultsadults

Sedation Sedation

AnxiolysisAnxiolysis

AnalgesiaAnalgesia

Depression of Depression of cough reflex, cough reflex,

miosis, addictive miosis, addictive propertiesproperties

Fentanyl Fentanyl 2 – 5 2 – 5 g/kg IV g/kg IV

Hemodynamics stability Hemodynamics stability

Absence of histamin Absence of histamin release release

Suppression of stress Suppression of stress responseresponse

More potent, short duration More potent, short duration

Muscle rigidity Muscle rigidity

Bradycardia Bradycardia

Pentazocine Pentazocine 0.4 mg/kg IV0.4 mg/kg IVLess respiratory depression Less respiratory depression

Low addictive property Low addictive property

Sympathetic over Sympathetic over activityactivity

Less sedation Less sedation

1. OPIOIDS 1. OPIOIDS :

2. BENZODIAZEPINES

DrugDrug Dose Dose AdvantageAdvantage DisadvatageDisadvatage

DiazepamDiazepam0.25-0.5mg/kg 0.25-0.5mg/kg

orallyorally

5-10mg iv5-10mg ivPotent sedative Potent sedative

Pain on injection Pain on injection

Long acting Long acting

MedazolamMedazolam

0.03 – 0.05 0.03 – 0.05 mg/kg IVmg/kg IV

0.5 mg/kg 0.5 mg/kg oral.oral.

Short acting Short acting

More potent More potent

Lorazepam Lorazepam

25 – 50 mg 25 – 50 mg oral oral

1 – 4 mg IV / 1 – 4 mg IV / IM. IM.

Age and liver Age and liver disease does not disease does not affect metabolismaffect metabolism

Long acting. Long acting.

3. ANTICHOLINERGIC

As a premedicant –

• Reduced secretions.

• Vagolytic

Drug Drug Vagolytic Vagolytic Antisialagogue Antisialagogue Sedation Sedation

& & Amnesia Amnesia

AtropineAtropine 3 +3 + 1 + 1 + 0 0

ScopolamineScopolamine 1 +1 + 2 + 2 + 3 + 3 +

Glycopyrolate Glycopyrolate 2 + 2 + 3 + 3 + 00

A. Antacids

B. H2 antagonists :

• Ranitidine – 50 – 200 mg orally

50 – 100 mg IV

C. Proton Pump Inhibitors:

• Omeprazole – 20 – 40 mg OD

• Lansoprazole – 15 – 30 mg OD

D. Prokinetics :

• Metoclopramide – 0.1 – 0.3 mg /kg IV

• Domperidone– 0.3 – 0.6 mg /kg orally

4. Drugs used to alter gastric fluid volume & pH :

5. ANTIEMETICS• Nausea and vomiting are single most common factor delaying recovry of patients.

1. 5HT3 Antagonist-

Ondansetron- 4-8mg iv

0.1mg/kg upto 4 mg in children

2. Butyrophenones-

• Droperidol 2.5 mg to 10 mg IM or IV.

3. Phenothiazine

• Promethazine, perphenazine, promazine.

Patients with COPD and Asthma :

• Bronchodilators , steroids should be continued

• Prophylactic antibiotics in COPD patients

• Opioids to be used cautiously – respiratory depression, bronchoconstriction

• Anticholinergics should be individualized – dries secretion difficult to remove

• NSAIDS should be avoided

Diabetes mellitus:• Objectives-

Avoid hypoglycemia , excessive hyperglycemia , ketoacidosis

Blood glucose should be maintained 120-180m

• OHD to be avoided on day of surgery

• Premedication to avoid aspiration and nausea vomiting

PREMEDICATION IN OBSTRETIC ANAESTHESIA

• Patients are at risk of aspiration due to –

Progesterone delays gastric emptying

Gravid uterus

Drugs esp opioids

• Opioids and BZD may cause adverse effect on neonate

• Amnesia – woman may not be able to remember her birthing experiences

PREMEDICATION IN PAEDIATRIC PATIENTS

• Premedication in infants-

•Infant less than 6 months don not require sedative premedication

•Antisialogouges no longer required in neonate

•Premedication in children-

• Aims –

• To get calm and comfortable child in operating room

• To decrease secretions

• To obtund vagal reflexes

• To avoid post op. behavioral disturbances

• Considering fear for needles , routes other than im / iv prefered

1.Sedatives and hypnotics-

Midazolam- most commanly used

0.5-0.75mg/kg orally 20 mins prior

0.2-0.3mg/kg intrnasal

0.4-0.5mg/kg per rectally

Trichlophos- 75-100mg/kg orally

2. Analgesics-Paracetamol syrup-5-10mg/kg

10-15mg/kg rectallyDiclofenac- 1.5mg/kg rectally

3. Opioids-

OTFC-in the form of lollypop

4. Ketamine- 6mg/kg orally

3mg/kg intranasally

3-5mg/kg im

5. Anticholinergics - Preffered, along with ketamine

Atropine- 0.02mg/kg im/iv

glycopyrrolate - 4-8ug/kg im/iv