Assessment of vena cava inferior diameter with ultrasonography in patients undergoing spinal anesthesia and evaluation of postoperative hypotension

Objective: Hypotension frequently occurs during spinal anesthesia and has serious complication that requires early and quick treatment. The goal of this study was to predict the state of fluids in the patient’s body through measurement via ultrasonography of the inferior vena cava diameter (IVCd) prior to administering the spinal anesthesia. This study also intended to investigate the presence or not of a relationship between the ultrasonography IVCd measurements before spinal anesthesia and hypotension. Material and Methods: A prospective study was performed in which the patients (n:115) were grouped based on their ultrasonography IVC transverse diameter measurements: those with <1.5 cm diameters were categorized as Group 1 (n:22), those having 1.5-2 cm diameter in Group 2 (n:67) and those possessing >2 cm diameter in Group 3 (n:26). The hemodynamic parameters of all the patients were measured. Results: Hypotension was observed in 23 (20%) patients, particularly in the 5th minute post administration of spinal anesthesia. Hypotension was especially high in Group 1 (52%) compared to Group 2 (34.8%) and Group 3 (13%) (p<0.001). Conclusion: We concluded that IVCd measurement with ultrasonography is a significant indicator which helps to determine the volumetric status of the patient. However, considering the development of the complication of hypotension post SA, it is felt that the IVC diameter measurement by USG might not always be adequate by itself, and needs to be assessed together with the clinical parameters of old age and presence of chronic diseases.