Friday, September 5, 2008

Some Cases Of Pediatrics

Some Cases Of Pediatrics

1.In a 2 months old infant undergoing surgery for biliary atresia, you would avoid one of the following anaesthetic:

A. Thiopentone
B. Halothane
C. Propofol
D. Sevoflurane

2.Regarding neonatal circumcision, which one of the following is true:
A. It should be done without anaesthesia as it is
hazardous to give anaesthesia
B. It should be done without anaesthesia as neonate
do not perceive pain as adult
C. It should be done under local anaesthesia only
D. General anaesthesia should be given to neonate for
circumcision as they also feel pain as adult

3. The ideal muscle relaxant used for a neonate undergoing porto-enterostomy for biliary atresia is:
A. Atracurium
B. Vecuronium
C. Pancuronium
D. Rocuronium

4. The narrowest part of larynx in infants is at the cricoid level. In administering anesthesia this may lead to all except:
A. Choosing a smaller size endotracheal tube
B. Trauma to the subglottic region
C. Postoperative stridor
D. Laryngeal oedema

Answers:

1-B (Halothane)
Discussion
Halothane has hepatotoxic potential which is increased in presence of decrease blood flow to liver and preoperative liver disease.

Explanation
A. Thiopentone: IV inducing agent,ultra short acting, 2.5% solution used leads to CNS depression lasting more than 12 hours. It is used for short operation that are not painful.
B. Halothane: Inhalational anesthetic,contraindicated in the presence of jaundice. It is a potent GA, poor analgesic or muscle relaxant. It leads to direct myocardial depression and respiratory depression. It causes severe hepatic necrosis (idiosyncratic). It is preferred in asthma as it is a bronchodilator.
C. Propofol: Action is for 15 minutes only,used in day-case surgery,dose dependent respiratory depression occurs.
D. Sevoflurane: Good for pediatric patients,pleasant even through face mask,recovery is smooth. It should not be used in closed circuit with sodalime as it is then degraded.

2-D (General anaesthesia should be given to neonate for circumcision as they also feel pain as adult)

Explanation
Neonates also have developed sensory system.

3- A (Atracurium)

Discussion
Atracurium: 4 times less potent than pancuronium and shorter acting too,can be used in liver and kidney disease also as it is eliminated spontaneously in plasma by non enzymatic degradation [by hoffman degradation]. Hemo-dy-namically it is neutral.so liver plays no role in it metabolism.

Explanation
The metabolism of atracurium is mainly by Hoffman degradation which is non-enzymatic, pH and temperature dependent.
The metabolism of vecuronium, pancuronium and rocuronium are dependent on liver and in biliary atresia liver functions are deranged.

4-A (Choosing a smaller size endotracheal tube)

Discussion
• Endotracheal tubes that pass through the glottis may still implinge upon the cricoid cartilage, causing postoperative edema, stridor, croup and airway obstruction
To pervent these complications, smaller size tube is selected.