Abstract :
Background and Objectives: The bispectral index (BIS), derived from EEG signals, is widely used to assess the depth of anaesthesia, ensuring optimal dosing and preventing intra-operative awareness. Sevoflurane and desflurane, commonly used volatile anaesthetics, share an equivalent minimum alveolar concentration (MAC) but may differ in hypnotic potency. This study compares their hypnotic effects at equi-MAC using BIS and evaluates associated haemodynamic parameters, including heart rate (HR) and mean arterial pressure (MAP).
Materials and Methods: A prospective, randomised trial included 80 adult patients (ASA I-II, aged 18–55 years) undergoing elective surgery under general anaesthesia. Patients were allocated into two groups: Group S (sevoflurane) and Group D (desflurane), receiving the respective agent at 1 MAC. Anaesthesia induction was standardized, and BIS, HR, and MAP were recorded at baseline and every 5 minutes for 30 minutes post-equilibration. Data were analyzed using independent t-tests, with p < 0>
Results: Desflurane resulted in lower BIS values (mean 44 ± 3) compared to sevoflurane (mean 49 ± 4), reflecting a notable decrease of approximately 10.2% in BIS with desflurane. Desflurane increased HR and MAP, likely due to sympathetic stimulation which may be significant in patients with cardiovascular conditions like hypertension, coronary artery disease or arrhythmias, as it could elevate myocardial oxygen demand and perioperative risk. Recovery times were faster with desflurane, with shorter durations for eye-opening (6.8 ± 1.9 minutes) and verbal response (8.5 ± 2.0 minutes) compared to sevoflurane (10.2 ± 2.1 and 12.3 ± 2.4 minutes, respectively).
Conclusion: Desflurane offers greater hypnotic potency and more rapid recovery than sevoflurane at equivalent minimum alveolar concentrations (MAC). However, its pronounced haemodynamic effects necessitate caution in hemodynamically unstable patients, highlighting the importance of tailoring anaesthetic management to individual clinical conditions.
Keyword :
Anaesthesia, Bispectral Index, Sevoflurane, Desflurane, Haemodynamic.