Comparison of Fat-Free Mass and Ideal Body Weight Scalar for Anesthetic Induction Dose of Propofol in Patients with Morbid Obesity: A Double-Blind, Randomized Clinical Trial

Background

Obesity is a growing problem worldwide and can affect both the pharmacodynamics and pharmacokinetics of various drugs, including anesthetics, resulting in the under-or overdosing of certain drugs. There is no consensus on the ideal dosing regimen for obese populations.

Objectives

In this study, 2 weight-based dosing of propofol used for induction of anesthesia were compared in terms of the onset of action time, adequacy of anesthesia, and effects on hemodynamic indices (eg, heart rate [HR] and blood pressure).

Methods

In this randomized, double-blind clinical trial, 40 patients with morbid obesity (MO) scheduled for bariatric surgery with body mass index (BMI) > 35, age 18 - 59 years, American Society of Anesthesiologists physical status (ASA-PS) II and III were randomly divided into 2 groups, using block randomization method, to receive 2 mg/kg of propofol for induction of anesthesia based on either fat-free mass (FFM) group or ideal body weight (IBW) group. The primary outcome was the time duration to reach the bispectral index (BIS) ≤ 60. Time to the disappearance of eyelash reflex, signs of inadequate anesthesia (ie, BIS > 60, straining during intubation, or eye-opening), requirements for additional doses, and hemodynamic indices (including HR and mean arterial pressure [MAP]) were also compared.

Results

The mean time to reach BIS ≤ 60 was 134.1 s in the FFM group and 148.7 s in the IBW group. This difference was not statistically significant (P = 0.334). The time of disappearance of eyelash reflex was also not significantly different between the study groups (P = 0.814). However, 2 patients in the FFM group and 8 patients in the IBW group showed signs of inadequate anesthesia and required additional doses. This difference was statistically significant (P = 0.032). Hemodynamic variables, before and 2 min after propofol induction dose administration were comparable between the study groups (P = 0.520, P = 0.327, P = 0.847, P = 0.516 for pre-intervention MAP, post-intervention MAP, pre-intervention HR, and post-intervention HR, respectively).

Conclusions

Propofol dosing, based on FFM and IBW, for induction of anesthesia, provides comparable onset time of action and hemodynamic effects; however, in terms of the adequacy of anesthesia, the dosing based on FFM is more favorable compared to the dosing based on IBW.

A Case Report of an Atypical Neurological Presentation of COVID-19 in Pregnancy

Symptomatic patients with coronavirus disease 2019 (COVID-19) mostly have flu-like symptoms. However, neurologic manifestations are common and may be the early findings of COVID-19. Data for COVID-19 do not indicate an increased risk of infection in pregnant individuals, but the risk of disease severity and mortality is high in this patient population. We report a case of a pregnant woman in the 10th gestational week, who presented with neurological symptoms of sudden impairment in walking, balance, speech, and consciousness, started the night before, and a seven-day history of fever, chills, myalgia, and general weakness before admission. The polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was positive for the cerebrospinal fluid sample a day before the positive nasopharyngeal sample. Axial brain magnetic resonance imaging revealed the involvement of the spinothalamic tract. Following treatment with intravenous immunoglobulin, the patient's neurological condition gradually recovered, except for lower limb muscle strength, and she was discharged from the hospital on the 10th day of admission. This case is unique as it emphasizes the importance of considering COVID-19 when uncommon neurologic manifestations with negative nasopharyngeal PCR are present.