Assessment of heart rate variability during different propofol effect site concentrations in patients with supratentorial tumours: A pilot study

Abstract

Background: Impaired autonomic function (AF) can result in adverse cardiovascular events during the perioperative period. Literature suggests that patients with intracranial space-occupying lesions experience impaired AF depending on the site of tumour and associated raised intracranial pressure (ICP). The complex interaction between general anaesthetics, AF and intracranial tumours with raised ICP has not been extensively studied. Objective: This study was aimed at evaluating the cardiac AF (in terms of heart rate variability [HRV]) in patients undergoing surgery for supratentorial tumours, at baseline and at different propofol effect site concentrations (Ce) during anaesthetic induction and the results were compared with patients undergoing non-cranial surgeries. Materials and Methods: In this prospective observational study, consecutive adult patients undergoing surgeries for supratentorial tumour (study group) and brachial plexus injury (control group) were recruited. Electrocardiogram was recorded for 5 min at three time points – before propofol induction, at propofol Ce 2 μg/ml and at Ce 4 μg/ml. Results: Forty-five patients were recruited, 24 in study group and 21 in control group. In spite of similar baseline heart rate and blood pressure, low frequency (LF), high frequency (HF) and total power were significantly higher in control group. Baseline LF/HF, though higher in patients with intracranial tumour (craniotomy: 2.2 ± 2.2, control: 1.2 ± 1.1), was not significantly different between the two groups (P = 0.197). HRV variables in both the groups changed the same way in response to the increasing propofol Ce. Conclusion: HRV measurements were significantly different at baseline between the two groups. Following propofol administration, haemodynamic changes and HRV changes were similar in both the groups and also between the two groups.