Internal jugular vein collapsibility as a predictor for hypotension after spinal anaesthesia– a prospective observational study

Hypotension after spinal anesthesia is a common event in routine anaesthesia practice, with a reported incidence of up to 90% (1). Although advanced age and sensory block above fifth thoracic vertebrae( T5 ) has been reported as the most important causes of post spinal hypotension, the presence of low intravascular volume related to chronic systemic diseases, poor physical condition, medications, and prolonged fasting time is also a well-known predisposing factor for this complication. (2,3) Severe or protracted intraoperative hypotension increases the risk of postoperative mortality and the emergence of critical diseases such as acute myocardial infarction, stroke, heart failure, and kidney failure.(4,5,6) Post spinal hypotension can be prevented by a number of treatment approaches, including preventive intravenous fluid replenishment and by giving vasopressors . However, most of them are ineffective and they have risky side effects, particularly in individuals who already have underlying cardiac and pulmonary disorders (7, 8).Therefore, adequate intravascular volume measurement before giving anaesthesia is crucial for preventing or minimizing such hypotensive episodes that can cause major issues. Even though central venous catheterization is quite effective in predicting intravascular volume status, its usage is constrained, particularly in elective, quick, or straightforward operations, due to its invasiveness, time-consuming nature, and potential associated problems. Therefore, non-invasive and straightforward techniques like sonographic examination of the Internal Jugular Vein (IJV) and Inferior Vena Cava (IVC) have become more popular in recent years (9, 10). There are many clinical researches that has looked into the usefulness of sonographic assessments of IVC in predicting intravascular volume prior to spinal anaesthesia ( 1,3,11). But very few researches has been done to determine if IJV ultrasonography can accurately predict post spinal hypotension.