Sir,
I read with great interest the letter, “Dangerous sedation in an obese patient”. I just wanted to stress upon certain points that are a must before accepting morbid obese patients.
With the obesity epidemic, awareness about the various pathophysiological changes in obesity and their sensitivity to various sedative drugs should be understood.
Point 1: The patient had a neck circumference of 47 cm and a body mass index (BMI) of 42.
In a morbid obese patient (patients with BMI of greater than 40), a neck circumference of greater than 40 cm should immediately alert the anaesthesiologist that this patient has a high index of suspicion of obstructive sleep apnea. Therefore, certain relevant points in the history can be remembered by the pneumonic 1.
Mandatory history in an obese patient is “CHUNGS criteria STOPBANG”[1]
S=snoring
T=tiredness daytime, morning headaches sleeping while Seeing favorite TV programme.
O=observed apnea
P=Pressure, i.e. hypertension
B=BMI>40
A=age>50 cm
N=neck circumference of >40 cm
G=gender male
Any patient with three or more criteria should be suspected to have obstructive sleep apnoea (OSA) or obesity hypoventilation syndrome (OHS), and further tests and preoperative stabilization with Bipap/continuous positive airway pressure (CPAP) is a must before surgery. Preoperative arterial blood gas analysis helps in determining the basal status of the patient.
Extreme sensitivity to anaesthetics and sedatives is noted in these patients, and the intake of alcohol worsens the symptoms. The response to hypercarbia is blunted in these patients due to the leptin (secreted by the visceral adipocytes) resistance. Therefore, they do not usually require any sedative premedication like alprazolam, etc.
The liver enzymes in this patient is SGOT=638 IU/l and SGPT=619. Disease is due to the fatty infiltration of the liver leading to inflammatory[2] changes in the liver and causing nonalcoholic steatohepatitis (NASH) and nonalcoholic fatty liver disease (NAFLD).
Alcohol could be an additional aetiological factor.
REFERENCES
- 1.Chung F, Yegneswaran B, Liao P, Chung SA, Vairavanathan S, Islam S, et al. STOP Questionnaire: A tool to screen patients for obstructive sleep apnea. Anesthesiology. 2008;108:812–21. doi: 10.1097/ALN.0b013e31816d83e4. [DOI] [PubMed] [Google Scholar]
- 2.Foxx-Orenstein AE. Gastrointestinal symptoms and diseases related to obesity: An overview. Gastroenterol Clin North America. 2010;39:23–37. doi: 10.1016/j.gtc.2009.12.006. [DOI] [PubMed] [Google Scholar]