EFFICACY OF FLUID ADMINISTRATION BY INFERIOR VENA CAVA ULTRASONOGRAPHY GUIDANCE VERSUS EMPIRICAL METHOD FOR PREVENTION OF ARTERIAL HYPOTENSION IN SPINAL ANESTHESIA PATIENTS UNDERGOING ORTHOPAEDIC SURGERIES - A RANDOMIZED CONTROLLED STUDY

Background: Spinal anesthesia is widely used for lower-limb orthopedic surgery but is frequently complicated by arterial hypotension due to sympathetic blockade and venous pooling. Empirical fluid loading has inconsistent efficacy and risks fluid overload. Ultrasonographic assessment of the inferior vena cava (IVC) collapsibility index (IVCCI) offers a non-invasive means of predicting fluid responsiveness and guiding individualized fluid therapy. Methods: In this single-center, randomized controlled trial, 100 ASA I–II adults aged 18–40 years scheduled for elective orthopedic surgery under spinal anesthesia were allocated to either IVC ultrasonography-guided fluid administration (Group A) or empirical fluid preloading (Group B). Group A received 500 ml Ringer Lactate boluses if IVCCI ≥ 36%, repeated until <36%. Group B received a fixed preload of 5 ml/kg Ringer Lactate. The primary outcome was incidence of post-spinal arterial hypotension (systolic BP <90 mmHg or diastolic BP <60 mmHg) within 30 minutes. Secondary outcomes included total crystalloid volume and vasopressor (mephentermine) requirement. Results: Hypotension occurred in 8% of Group A versus 28% of Group B (p = 0.019). Group A received more total fluid (726 ± 71.6 ml) than Group B (611.1 ± 113.4 ml, p < 0.001), but fewer mephentermine boluses (0.12 ± 0.33 vs. 0.34 ± 0.56, p = 0.018). Mixed-effects models showed significantly better maintenance of systolic and mean arterial pressure in Group A (p < 0.01). Conclusion: IVC ultrasonography-guided fluid therapy significantly reduced the incidence of post-spinal hypotension and vasopressor use compared with empirical preloading, supporting its use for individualized perioperative hemodynamic management in orthopedic anesthesia.