Background: Spinal Anaesthesia is the most preferred route of anaesthesia in parturients for caesarean section. Maternal hypotension after spinal induction is the most common complication which may result in adverse maternal and foetal outcomes. The decrease in systemic vascular resistance due to the blockade of pre-ganglionic sympathetic fibres causes maternal hypotension. Analysis of heart rate is the most economical, easiest non-invasive method of assessment of the autonomic nervous system.

Material and Methods: This is a prospective observational study carried out at NSCB medical college and hospital, Jabalpur from March 2019 to August 2020 on 225 pregnant women who underwent elective caesarean section under spinal anaesthesia. All patients were explained in detail about the anaesthetic procedure and written informed consent was obtained. All the patients were pre-loaded with lactated Ringer’s solution (15ml/kg) 15 min prior to spinal anaesthesia. Basal HR was determined with pulse oximeter by taking average of five independent recordings, every minute in sequence. Immediately after subarachnoid block, blood pressure measurement was recorded and repeated every 3 min in first 30 min and cycled to 5 min till end of surgery. Patients developing more than 20% drop in themean arterial pressure (MAP) were treated with parenteral ephedrine 3 mg bolus. The foetuses were monitored immediately at 1 min and 5 mins immediately after birth and APGAR scores were calculated.

Results: Significant positive correlation of baseline maternal Heart Rate with post-spinal hypotension and vasopressor requirements was noted. Subjects with baseline HR ≥ 90 beats per minute had an 81% chance (Positive predictive value) of developing marked hypotension after SA. There was no significant difference in APGAR scores based on the degree of hypotension observed.

Conclusion: Baseline HR prior to hydration may be useful to predict post SA hypotension. Higher baseline HR, possibly reflecting a higher sympathetic tone, may be a useful parameter to predict postspinal hypotension.