Preload versus co-load of Ringer’s lactate to prevent hypotension during elective Cesarean section under spinal anesthesia: a single-blind randomized clinical trial

<title>Abstract</title> <p>Background Spinal anesthesia (SA) is used for Cesarean section (C/S) with maternal hypotension. We aimed to compare the preload and co-load of Ringer’s lactate for the prevention of hypotension during elective C/S under SA. Methods This single-blind randomized clinical trial included 60 women aged 18–45 years with singleton-term pregnancies. Patients were randomly allocated to two groups, the preload group (group P) and the co-load group (group C). Then, the American Society of Anesthesiologists (ASA) physical status class, hemodynamic parameters, maternal complications, and neonatal outcomes were recorded and compared between groups. Results Hypotension occurred in 23 (76.6%) of patients in group P and 24 (80%) in group C (P = 0.179). Bradycardia was also more frequent in group C (20% vs. 10%, P = 0.278). Mean oxygen saturation (SpO2) was significantly higher in group P at all time points (P &lt; 0.05) except SpO2 at baseline, immediately after SA, and at 60 min (P &gt; 0.05). Apgar at 5 min was significantly higher in group C (P = 0.007). Shivering occurred more frequently in group P (56.6% vs. 13.4%, P = 0.001). Nausea and/or vomiting was also more common in group P (33.3% vs. 23.3%, P = 0.403). Conclusions Both preloading and co-loading with Ringer’s lactate demonstrate comparable effectiveness in hemodynamic stabilization during spinal anesthesia for elective C-section. Given the lack of statistically significant differences in hypotension and bradycardia rates, along with higher rates of shivering in the preload group, neither technique shows a clear superiority over the other. Trial registration: IRCT20110313006044N5. Registered on 25 March 2022</p>