Minimum alveolar concentration (MAC) versus entropy in patients undergoing general anaesthesia: Hemodynamic changes

Abstract

Minimum alveolar concentration provides a correlation between anesthetic dose and immobility. It can 
be applied to all inhalational anesthetics and is used to compare anesthetic potency. Research conducted 
in both animal and human subjects has revealed that volatile anesthetics depress the excitability of spinal 
motor neurons, underscoring the role of inhaled anesthetics in mediating immobilization primarily at the 
spinal cord level. Routine pre-anaesthetic check-up was done prior to the surgery as per the routine 
preoperative protocol, by collecting basic demographic details, history of comorbid illness and drug 
therapy. All the patients were subjected to general and systemic examinations. Also, airway assessment 
was carried out and documented. As per first 2 comparisons, the mean SBP of 118.47 ± 10.23 at 0.8 
MAC was significantly higher than either 114.37 ± 8.19 at 1.0 MAC or 109.47 ± 7.36 at 1.3 MAC. In 
last comparison, the mean SBP of 114.37 ± 8.19 at 1.0 MAC was also found to be significantly higher 
than 109.47 ± 7.36 at 1.3 MAC. Thus in all 3 comparisons, the study found significant difference thereby 
confirming significant decrease in SBP with increase in MAC.