Hypotension in spinal anesthesia: predictive factors, prevention and volemia’s non-invasive estimation methods

Introduction. Evaluation of patient volemia arriving at a medical service today still represents a challenge for specialists, especially in those who need surgical and anesthetic intervention. One of the most common systemic side effect to anesthesia is hypotension. Spinal Anesthesia-Induced Hypotension (SAIH) because of sympathetic blockade is most frequently cited as a complication of subarachnoid anesthesia, its severity being influenced by the patient’s volemic state. The aim of this literature review is to analyze if „routine” preanesthetic preloading reduces the incidence of SAIH in patients undergoing spinal anesthesia, also to emphasize the efficacy of preanesthetic assessment of the IVC/Ao (Inferior Vena Cava/ Abdominal Aorta) Index measured by ultrasound in determination of patients’ volemia. Material and methods. Narrative literature review. Bibliographic search in the PubMed, NCBI and Google Academic databases, using the keywords: „hypotension inferior vena cava”, „hypotension spinal anesthesia”, „inferior vena cava/aorta diameter”, „preloading hypotension”, which were combined with each other. The final bibliography included 40 references. Results. The principles of perianesthetic volemia management and prevention of arterial hypotension after the administration of the spinal block were detected in different groups of patients: the elderly, adult patients, anesthesiologic assistance in obstetrics and in various types of surgical interventions. Hypotension incidence data in patients with and without preanesthetic volume repletion were detected. At the same time, the effectiveness of the ultrasonographic assessment of IVC/Ao index in assessing patient’s volume status was determined. The information was analyzed and synthesized in the article. Conclusions. The effectiveness of routine preloading in reducing the incidence of arterial hypotension after spinal anesthesia did not prove its benefits in normovolemic patients, and ultrasonographic assessment of the IVC/Ao Index in assessing the volume status appears to be a simple, rapid, non-invasive, cost-effective volume assessment, which does not require the presence of a specialized imagist, being practically devoid of contraindications.