A Comparative Study of Preloading Versus Coloading of Crystalloid to Prevent Spinal Anaesthesia Induced Hypotension

CONTEXT: Preloading of crystalloid is a traditional practice to prevent spinal anaesthesia induced hypotension. But coloading seems to be more physiological and rational approach as effect was achieved during the time of spinal anaesthesia. AIMS: To compare crystalloid preload and coload for the prevention of spinal block induced hypotension in lower limb surgeries. Secondary outcomes included no. of dose of mephenteramine & atropine, bradycardia, nausea, vomiting, total volume of infusion, blood loss & urine output. SETTINGS AND DESIGN: Tertiary level, teaching hospital. Prospective, randomized study. MATERIALS AND METHODS: Total sixty patients of either sex, aged 20 to 60 years, scheduled for lower limb surgery under spinal anaesthesia were randomized into preload and coload group, 30 patients in each group. In preload group, 20 ml/kg of Ringer lactate was preloaded 20 minutes before commencement of spinal anaesthesia. In group Coload, 20 ml/kg of Ringer lactate was coloaded in 20 minutes just after lumbar puncture. STATISTICAL ANALYSIS USED: Quantitative data were compared with student's t test and qualitative data with chi-square or fisher exact test. P<0.05 was considered significant. RESULTS: patient characteristics were comparable in both groups (p>0.05). Mean baseline value and trends at various time intervals of heart rate, systolic blood pressure, diastolic blood pressure, mean blood pressure were comparable in both groups. Total incidence of hypotension in group Preload and group Coload were 13.33% and 10% respectively (p=0.463). Total incidence of bradycardia in group Preload and group Coload were 6.67% and 10% respectively (p=0.394). No. of dose of atropine to treat bradycardia was 2 out of 30 patients (6.67%) and 3 out of 30 patients (10%) for group P and C respectively (p=0.394). No. of dose of mephenteramine to treat hypotension was 4 out of 30 patients (13.33%) for each group (p=1). Incidence of nausea was 6.67% for group Preload and 10% for group Coload (p=0.394). Incidence of vomiting was 3.33% for group Preload and 6.67 % for group Coload (p=0.278). Total volume used for preloading was about 1474 206 ml and for coloading was 1386 176 ml (p=0.0805). Urine output in preloading and coloading groups was 223 100 and 173 89 ml respectively (p=0.0453). CONCLUSIONS: Coloading with 20 ml/kg of Ringer's lactate was as effective as preloading of same amount 20 minute before lumber puncture to prevent spinal induced hypotension.