Comparison of inferior vena cava diameter and perfusion indexvalues with determination of hypotension risk in spinal anesthesia

Predetermination of cases in which hypotension occur after spinal anesthesia may reduce mortality and morbidity rates. Studies have shown that inferior vena cava (IVC) diameter and perfusion index (PI) values are effective in evaluating intravascular volume status and the risk of developing hypotension.We aimed to compare the IVC diameter measurements with ultrasound and PI values in determining the risk of developing hypotension in patients with spinal anesthesia. The study included 90 patients over 40 years of age who underwent ASA I-III, transurethral resection of the prostate. Preoperative PI and pleth variability index (PVI) values, IVC diameters (during inspiration, IVCmin and during expiration; IVCmax) and IVC collapsibility index (IVCCI) values were recorded. Spinal anesthesia with hyperbaric bupivacaine was performed. Hypotensive group was defined as a decrease of systolic arterial blood pressure of more than 25% from baseline After spinal anesthesia, hemodynamic parameters, PI, PVI values were recorded every 5 minutes within the first hour of operation, then every 15 minutes. Level of maximum sensory blockade, duration of operation, amount of intraoperatively administered bupivacaine,fluid and irrigation fluid,, doses of ephedrine and atropine during hypotension and bradycardia were recorded. IVC diameters and IVCCI values were re-measured in the 0.,5. min after spinal anesthesia and at the end of the operation. The results of 81 patients were evaluated, because the IVC measurement could not be performed in 9 patients. The frequency of hypotension was found to be 39.5% after spinal anesthesia. Baseline IVCmin ≤0.99cm (AUC: 0.644, p=0.018) and baseline IVCCI> 44.5% (AUC: 0.628, p=0.047) were found as risk factors for development of hypotension. In hypotensive group, IVCmax and IVCmin values were low and IVCCI values were high during intraoperative period. There was no difference between PI and PVI values in cases with and without hypotension. As a result;.PI values are not effective but IVC measurements may be useful determining the risk of developing hypotension after spinal anesthesia.