Impact of Needle Bevel Orientation on Hemodynamic Stability and Quality of Spinal Anesthesia for Cesarean Section: A Prospective Randomized Study

Introduction: Maternal arterial hypotension is the most common complication of spinal anesthesia for cesarean section, potentially compromising maternal and fetal safety. The objective of this study was to evaluate whether a simple technical modification, the orientation of the needle bevel, could reduce the incidence of this hypotension. Methods: A prospective, randomized, comparative study was conducted on 100 parturients (ASA I-III) undergoing emergency cesarean section. Patients were divided into two groups: Group I (n=54) received spinal anesthesia with a conventional cephalad bevel orientation, and Group II (n=46) with a caudad orientation. All participants received 10 mg of hyperbaric bupivacaine and 25 mcg of fentanyl. The primary endpoint was the incidence of hypotension (defined as SBP < 100 mmHg or a drop > 20% from baseline). Results: The incidence of hypotension was significantly lower in the caudad orientation group (10.8%) compared to the cephalad orientation group (38.8%, p = 0.039). Ephedrine consumption was reduced by over 70% in the caudad group (3.0 ± 1.8 mg vs 11.9 ± 4.2 mg, p < 0.05). Furthermore, 78.3% of patients in the caudad group required no vasopressors, compared to 37% in the cephalad group (p < 0.05). The sensory block level was lower (T5 vs T3) and had a slower onset (time to T6: 10 vs 6 min) in the caudad group, while remaining clinically effective. Conclusion: Caudad orientation of the needle bevel is a simple, effective, and cost-free technique to improve the safety of obstetric spinal anesthesia. It significantly reduces the incidence of maternal hypotension and vasopressor consumption, at the cost of a slightly slower onset of the anesthetic block.