B406 Preoperative bedside ultrasound guided inferior venacava collapsibility index as a guide to predict hypotension following spinal anesthesia in patients scheduled for elective surgery

Background and Aims

Spinal anesthesia is the most commonly employed anesthetic technique for infraumbilical surgeries. Post spinal hypotension is a commonly encountered complication which can lead to organ hypoperfusion and ischemia. Severe episodes of intraoperative hypotension have been proposed as an independent risk factor in the development of postoperative adverse outcomes and prolonged hospital stay. However there are no reliable methods to determine which patients are at risk for spinal induced hypotension. This study investigated whether preoperative ultrasound guided inferior venacava collapsibility index (IVC-CI) could predict hypotension following spinal anesthesia.

Methods

After the approval of ethics committee, preoperative ultrasonography was done to determine the IVC-CI in 73 patients undergoing elective surgeries under spinal anesthesia. All ultrasonographic examinations were performed by the same anesthesiologist. Baseline heart rate, systolic blood pressure, diastolic blood pressure and mean arterial blood pressure were recorded prior to spinal anesthesia and also every 5 minutes following spinal anesthesia for 30 mins. Amount of mephentermine administered was also recorded.

Results

Operative procedures included 52 orthopedic and 22 general surgeries. 53.4% of all patients had significant hypotension post spinal anesthesia. 100% of patients with a IVC-CI≥50% had significant hypotension compared to 37% with a IVC-CI<50%, p=0.004. IVC-CI≥50% has a specificity of 100% (95%CI, 64.29%-90.26%) and sensitivity of 48.72% (95%CI, 52.06%-81.28%) in predicting post spinal hypotension.

Conclusions

Patients with IVC-CI≥50% were more likely to develop significant spinal induced hypotension.