Evaluating the Relationship between the Pleth Variability Index and Hypotension and Assessing the Fluid Response in...

We aimed to test the efficacy of the pre-operative Pleth variability index (PVI) in evaluating hypotension that developed after spinal anaesthesia in patients who were spontaneously breathing, pre-operatively hypovolemic, and were at an advanced age.

This observational study included 94 patients aged >65 years with hip fracture. Demographic data, pre-operative heart rate, non-invasive arterial pressures, PVI values, and haemogram values were continuously measured following spinal anaesthesia. The measurements with and without hypotension were distinguished and their data were compared.

The mean age of the patients was 77.4±8.2 years. In total, 56.4% of the patients developed hypotension after spinal anaesthesia, and hypotension was higher in women (p=0.037). Low pre-operative diastolic arterial pressures values were associated with the development of hypotension (p=0.037). The relationship between PVI and post-spinal hypotension was negative but significant (r=-0.239; p<0.05). Depending on the volume loss, an increase in the PVI (p<0.001) and its subsequent significant decrease after treatment in patients with hypotension (p<0.001) was observed. The correlation between noninvasively measured haemoglobin values and the values obtained from arterial blood gas samples was significant (p<0.001).

This study showed that post-spinal hypotension may be associated with increased as well as decreased PVI values. However, these values cannot be clinically used for predicting pre-operative hypotension in hypovolemic patients.