P032: DELAYED RECOVERY IN AN 85 YR OLD: AN INTERESTING CASE OF UNDIAGNOSED PSEUDOCHOLINESTERASE DEFICIENCY
Nicholas Scoglio, DO, PGY, Candice Hithe, DO, Andrew Dvoransky, MD; Largo Medical Center
Though commonly discussed in anesthesia textbooks, pseudocholinesterase deficiency is a relatively rare event in daily practice, affecting roughly 1 in 1,500-2,500 people. Diagnosed during the perioperative course, the deficiency stems from a recessive genetic defect in which the effects of depolarizing neuromuscular blocking agents, such as succinylcholine, are prolonged, leading to potential prolongation of the perioperative period. In order to better assist clinicians in diagnosing this rare enzymatic mutation, the dibucaine number, a local anesthetic with known inhibitory properties of the native enzyme, has become an indirect qualitative measure of the enzyme's function. Dibucaine values less than 70-80 are implicated in variant forms of pseudocholinesterase.
In this case report, we present a unique clinical scenairo of pseudocholinesterse deficiency in an 85yr old female patient presenting for acute laporascopic cholecystectomy; patient's prior anesthetic history was significant for "slow awakening". During this visit, the patient's perioperative course involved prolonged mechanical ventilatory support secondary to weakness. After an additional four hours of postoperative support, the patient was safely extubated with no complications. Ten days later a dibucaine laboratory test resulted, indicating a reduced value of 41.
Perioperative assessment of the patient revealed a history of slow emergence with anesthesia. Prior surgical history included colonic resection. Current medications were: gabapentin, aspirin, lisinopril, magnesium, and CoQ10. Uneventful induction was carried out with 90mg propofol, 100mg succinylcholine, and 50mcq fentanyl. Quantitative train of four stimulation was monitored at the obicularis oculi site and was found to be delayed approximately thirty minutes. At that time train of four revealed four twitches, although all low intensity, with 1:4 subjective ratio of 0.8. Prolonged neuromuscular relaxation was achieved with cisatracuronium. At the end of the procedure, train of four testing revealed similar pattern of train of four, with 1:4 ratio of 0.8. At that time, neostigmine (3mg) and glycopyrolatte (0.2mg) were given. Patient was breathing spontaneously and extubated. Upon arrival in PACU, patient noted to have difficulty breathing, reduced inspiratory effort and reduced arousal to stimulus. Decision was made to reintubate and place the patient on mechanical ventilatory support. Train of four testing again demonstrated low intensity 4/4 twitches; an additional 2mg neostigmine was administered. Over the course of four hours in PACU, patient had progressive improvement in muscle strength and respiratory effort. Patient was extubated at this point with no complications. At that time decision to run a dibucaine laboratory test was made and ten days later revealed a value of 41. Patient was contacted for relaying genetic testing and a formal letter was sent.
In this report we identify an interesting example of undiagnosed pseudocholinesterase deficiency. Though slow awakening from anesthesia in the elderly population is an acknowledged occurrence, this report identifies additional factors that may need to be considered during instances of delayed emergence. Specifically, quantitative train of four, though sensitive for detecting prolonged neuromuscular weakness, proved inadequate in this case. Qualitative testing as the gold standard may have improved diagnostic accuracy for detecting neuromuscular strength, and may be particularly valuable in the elderly population.