1q: which muscle relaxant increases intracranial pressure ?
a. mivacurium b. atracurium c. suxamethonium d. vecuronium
-- succinyl choline or suxamethonium causes increases in
1.intracranial pressure, 2.intraocular pressure, 3.intragastric pressure . this question was asked in AIIMS November 2002 paper .
2q: the use of succinyl choline is not contraindicated in ?
a. tetanus b. closed head injury c. cerebral stroke d. hepatic failure
succinyl choline is short acting muscle relaxant as it is rapidly metabolized by pseudocholinesterase secreted both by liver and plasma . in liver failure this enzyme is reduced ,so succinyl choline concentration is increased during liver failure and is also maintained for greater periods . but this does not mean that succinyl choline should be contraindicated in liver failure. The duration of paralysis produced by succinyl choline is increased during liver failure but this does not require succinyl choline to be contraindicated in liver failure .
conditions where succinyl choline use is contraindicated due to hyperkalemia caused by succinyl choline are :
-- this question was also asked in AIIMS November 2002 paper .
3q: a six year old boy is scheduled for examination of the eye under anaesthesia. The father informed that for the past six months , the child is developing progressive weakness of both legs. His elder sibling had died at age of 14 years. Which drug would you definitely avoid during the anaesthetic management ?
succinyl choline
thiopentone
nitrous oxide
vecuronium
-- weakness of the legs indicate that the boy is suffering from myopathy ( most probably duchenes muscular dystrophy ). Succinyl choline is contraindicated in myopathy due to increased risk of hyperkalemia .
-- this question was also asked in the november 2002 AIIMS paper .
If malignant hyperthermia is suspected intraoperatively
a. Complete the procedure but pretreat with dantrolene prior to future elective surgery b. Administer inhalational anesthetic agents c. Administer succinylcholine d. Hyperventilate with 100% oxygen e. Acidify the urine to prevent myoglobin precipitation in the renal tubules
The answer is d. (Schwartz, 7/e, pp 448, 499.)
The cause of malignant hyperthermia is unknown, but it is associated with inhalational anesthetic agents and succinylcholine. It may develop in an otherwise healthy person who has tolerated previous surgery without incident. It should be suspected in the presence of a history of unexplained fever, muscle or connective tissue disorder, or a positive family history (evidence suggests an autosomal dominant inheritance pattern). In addition to fever during anesthesia, the syndrome includes tachycardia, increased O2 consumption, increased CO2 production, increased serum K+, myoglobinuria, and acidosis. Rigidity rather than relaxation following succinylcholine injection may be the first clue to its presence. Treatment of malignant hyperthermia should include prompt conclusion of the operative procedure and cessation of anesthesia, hyperventilation with 100% oxygen, and administration of intravenous dantrolene. The urine should be alkalinized to protect the kidneys from myoglobin precipitation. If reoperation is necessary, one should premedicate heavily, alkalinize the urine, and avoid depolarizing agents such as succinylcholine. Pretreatment for 24 h with dantrolene is helpful; it is thought to act directly on muscle fiber to attenuate calcium release.
