Perfusion Index as a Predictor of Hypotension Following Propofol Induction: A Prospective Observational Study

Propofol, an induction agent for general anesthesia (GA), is associated with a significant risk of hypotension. Perfusion index (PI) is known to predict vascular responses in various situations; however, its utility in the prediction of hypotension postpropofol administration is not fully established.

To evaluate the performance of PI in the prediction of hypotension postinduction with propofol.

This observational, prospective study involved 120 adult patients who underwent elective surgeries under GA. The PI, heart rate, systolic blood pressure (SBP), diastolic blood pressure, mean arterial pressure (MAP), and oxygen saturation were recorded at baseline, postinduction (every minute for the first 5 min), and postintubation (every minute for the first 10 min and then at 5-min interval till a total of 20-min). Hypotension was defined as a fall in SBP by >20% of baseline or MAP <60 mmHg.

As per SBP and MAP criteria, the incidence of hypotension during induction was 28.3% and 35.8%, respectively, with corresponding values during postintubation period being 22.5% and 29.2%, respectively. Based on the SBP and MAP criteria (area under the curve [AUC]: 0.810 and 0.76, respectively; cutoff: 1.08), at 5 min, PI had sensitivity of 73% and 71%, and specificity of 74% and 69%, respectively. At 10 min, based on the SBP (AUC: 0.66, cutoff: 1.15) and MAP (AUC: 0.77, cut-off: 1.17) criteria, PI had a sensitivity and specificity of 65% and 52%, and 71% and 65%, respectively.

The baseline PI is a useful noninvasive tool for the prediction of hypotension, with MAP criterion performing slightly better than SBP criterion.