Dexmedetomidine as a Pediatric Anesthetic

Premedication to Reduce Anxiety and to

Deter Emergence Delirium

Renee Vicari RN, BSN, CCRN, SRNAOakland University/Beaumont HospitalGraduate Program of Nurse Anesthesia

Mountain, BW., Smithson, L., Cramolini, M., Wyatt, TH., Newman, M. (2011). Dexmedetomidine as a pediatric anesthetic premedication to reduce anxiety and to deter emergence delirium. AANA Journal, 79(3), 219-224.

IntroductionPublished in the June 2011 issue of American

Association of Nurse Anesthetists (AANA) Journal.

Study was approved by both an affiliated university and the hospital institutional review board.

Key Terms!Emergence Delirium (ED)- is a mental

disturbance common in children during recovery from general anesthesia.Symptoms:

Combative movementsThrashing, excitabilityDisorientationInconsolable crying

Purpose of StudyTo compare the effects of oral

dexmedetomidine and midazolam in reducing anxiety and ED in children aged 1 to 6 years receiving dental restoration.

Review of LiteratureKain and colleagues reported that pre-operative

anxiety may be linked to emergence delirium.

54% of their subjects had negative behavior patterns at 2 weeks and 20% of these continued for up to 6 months. Follow-up study found that children with pre-operative

anxiety had a higher excitement score in PACU and negative behaviors at home.Bad dreamsWaking up cryingSeparation anxiety Temper tantrums

Review of LiteratureSevoflurane, perioperative medications and pain

increase ED.

Midazolam most common medication used pre-op to reduce anxiety.

Dexmedetomidine IV shown to reduce ED when given intraoperative.

Limited studies on dexmedetomidine use in childrenRestricted to IV use

Hypothesis2 Part Hypothesis:

Oral dexmedetomidine is as effective as midazolam in reducing anxiety, as measured by tool assessing separation from parent and acceptance of mask, prior to surgery.

Oral dexmedetomidine reduces the incidence and severity of ED in pediatric population.

Study

RandomizedProspectiveDouble-blinded design

Inclusion CriteriaIncluded 41 children

Aged 1 to 6 years old

Undergoing dental restorations and possible tooth extraction.

Exclusion CriteriaKnown allergies to midazolam and or

dexmedetomidine

Developmental delay or mental retardation-as reported by the parents

History of ED

ASA classification greater than II

Any previous reactions to anesthesia

MethodsObtained informed consent

Subjects were randomly assigned to 1 of 2 groupsControl group:

Received 0.5mg/kg of oral midazolamExperimental group:

Received 4mcg/kg of oral dexmedetomidine

Staff and members of research team blinded to assignments and medication administered.

MethodsBoth medications were prepared in similar

syringes

Prepared with cherry-flavored syrup

Dexmedetomidine (Precedex)

Non-selective alpha-2 adrenergic agonist

Sedative and opioid sparing effects

Expensive-$495.79

IV infusion-0.2-0.7mcg/kg/hr

Minimal respiratory depression

Adverse effects: N/V Bradycardia Hypotension Fever

Midazolam (Versed)Benzodiazepine

Amnestic and anxiolytic properties

0.5mg-1.0mg/kg PO in children

Adverse effects:HeadacheDrowsinessConfusionN/VBlood pressure changes

Instruments3 instruments used

Parental Separation Anxiety Scale (PSAS) -4 point scale1=easy separation2=whimpers, but is easily reassured, not clinging3=cries and cannot be easily reassured, but not

clinging to parents4=crying and clinging to parents

PSAS of 1-2 acceptable

PSAS of 3-4 were difficult separations

InstrumentsMask Acceptance Scale (MAS)-ability to accept the

anesthesia mask

MAS scale is a 4-point Likert scale 1=excellent (unafraid, cooperative, accepts mask

readily) 2=good (slight fear of mask, easily reassured) 3=fair (moderate fear of mask, not calmed with

reassurance) 4=poor (terrified, crying, or combative)

Score of 1-2 was satisfactory

Score of 3-4 was unsatisfactory

InstrumentsPediatric Anesthesia Emergence Delirium Scale

(PAEDS)

Based on 5 criteria:Makes eye contact with caregiverActions are purposefulAware of his or her surroundingsRestless Inconsolable

Out of 20 points, a score greater than 10 indicates ED.

Data AnalysisPearson X2 analysis was performed to

determine differences between both groups for anxiety

Independent sample t test was used to determine differences between occurrence and severity of ED in both groups.

Level of significance was set at P=0.05

ProceduresStudy medication administered 30 minutes prior

to OR

Pulse oximetry and blood pressure monitored every 15 minutes

Research team member accompanied child to surgery and the PSAS was scored at this time-30 minutes after child received medication

In OR with nurse anesthetist, team member calculated the MAS score

ProceduresStudy anesthesia protocol:

Mask induction with sevoflurane and nitrous oxide Isoflurane used for maintenance Spontaneous ventilation was maintained if possible Muscle relaxants were avoided, if possible, if ventilatory

support needed. Anticholinergic drugs were avoided Odansetron (0.2mg/kg) and dexamethsone (0.25mg/kg)

were administered Fentanyl for analgesia (1 to 2 mcg/kg) Local anesthestic per surgeon

ProceduresTaken to PACU after surgery

Observed for 1 hour

PAEDS score was determined once child aroused or peak of ED

Results41 subjects recruited between May 2006 and June

2007

21 (51%) males

20 (49%) females

Mean age 4 years old

27 (65%) white

9 (22%) African American

5 (12%) Hispanic

ResultsNo difference in mean blood pressure values in

the 2 groups (t=0.852, P=0.399)

No difference in the pulse oximetry values in the 2 groups (t=0.459, P=0.649)

No difference in separation from parents between the 2 groups (X2=0.478, P=0.489)

No statistically significant differences between the 2 group with acceptance of the anesthesia mask (X2=0.602, P=0.438)

Results

ResultsOut of 41 subjects

8 children (20%) experienced ED3 of the 8 were in the experiemental

(dexmedetomidine) group5 were in the control (Midazolam) group

No significant difference between the 2 groups (t=1.023, P=0.313)

DiscussionStudy was able to demonstrate that 4mcg/kg PO

of dexmedetomidine resulted in no adverse effects

No difference between the midazolam and dexmedetomidine groups in blood pressure or oxygenation stability

StrengthsDouble-blinded study

All subjects remained in study

Equal number of males and females

Detailed and precise anesthesia protocol while child is anesthetized

Specific surgery-all subjects underwent same surgery

LimitationsLimited sample size

Absence of fluctuations in blood pressure and heart rate (common side effect) with dexmedetomidine may indicate that 4 mcg/kg was too low to be clinically effective.

Used oral dexmedetomidine instead of buccal Bioavailability is 16% (oral) compared to 82%

(buccal)

ConclusionNot FDA approved for children….yet

More studies needed to examine child-friendly dexmedetomidine preparations and its effect on ED