Frequency of anesthetic overdose with mean alveolar concentration-guided anesthesia at high altitude

Abstract

This study reported the frequency of anesthetic overdose measured with the bispectral index in a high altitude city (Bogotá-Colombia, 2600 meters above sea level). We assembled a prospective cohort of patients. Preoperative variables were described, and 10 minutes after the surgical incision, bispectral index, mean alveolar concentration, mean arterial pressure, and oxygen saturation were recorded. Bispectral index was classified as superficial (60), adequate (40–60), and deep (> 40). Mean alveolar concentration was classified as low (< 0.8), normal (0.8–1.2), and high (> 1.2). We included 50 patients. The mean age of the patients was 36.3 ± 13.5 years; 48% were male and 78% were categorized as ASA I. Mean values of mean alveolar concentration and bispectral index were 1.14 ± 0.18 and 38.66 ± 6.9, respectively. Frequency of anesthetic overdose measured with bispectral index was 54% and only 20% with mean alveolar concentration. In total, 78% of patients received normal mean alveolar concentration values, and among these patients, 49% had deep bispectral index levels and 51% were adequate. There was no correlation between mean alveolar concentration and bispectral index (Pearson r = 0.161, P = 0.246) or between bispectral index and mean arterial pressure (Pearson r = 0.367, P = 0.08). All patients older than 60 years exhibited deep bispectral index levels, and although we did not identify a correlation between age and bispectral index, a tendency was observed (Pearson r = –0.087, P = 0.538). Safe and effective anesthesia overdose could be a common phenomenon. Bispectral index-guided anesthesia could be a helpful and reliable tool in the assessment and prevention of anesthesia overdose at high altitude. The study was approved by the ethics committee of the Fundación Cardioinfantil-Instituto de cardiología, Bogota, Colombia (approved number: 312017).

Respiratory physiology at high altitude and considerations for pediatric patients

“…Although one prospective study suggests that inhalation anesthetic dose requirements might be lower at altitude, as determined by more frequent deep BIS values at moderate levels of MAC, this finding of relative anesthetic overdose at altitude when 'normal' MAC values are administered needs further corroboration, as the authors did not modify MAC values for age. 16 There are limited objective data on specific anesthetic regimens or drugs comparing their pharmacodynamic effects at altitude compared with sea level. Knowing that ventilatory responses and respiratory control during sleep can be adversely affected (see below), caution should be used when prescribing opioids and benzodiazepines, as they may have exaggerated effects on control of breathing under hypoxic conditions.…”

Dose-related adaptive reconstruction of DMN in isoflurane administration: a study in the rat

“…However, inadequate administration of anesthetics may result in intraoperative awareness, leading to negative psychological effects and potential medicolegal issues [ 2 , 3 ]. Conversely, excessive dosages of anesthetics can cause physical harm or even death [ 4 , 5 ]. It is crucial to carefully monitor and adjust anesthesia levels to ensure patient safety and successful surgery outcomes.…”