[Practice of spinal anesthesia in a developing country: usefulness of vascular preloading with a 7.5% hypertonic saline solution]

Abstract

Objective: To assess the efficacy of hypertonic saline for prevention of arterial hypotension in patients undergoing spinal anaesthesia in Niger.

Study design: Prospective, randomized, double-blinded study.

Patients: Fifty adults undergoing scheduled surgery under spinal anaesthesia, allocated either to a hypertonic saline group (HSG) or a isotonic saline group (ISG).

Methods: Over the 15 min prior to anaesthesia, 100 mL of 7.5% saline were infused in patients of HSG, and 100 mL of 0.9% saline in those of ISG respectively. Spinal anaesthesia was performed at the L3-L4 or L4-L5 interspace using either lidocaine 5%, or bupivacaine 0.5% or a mixture of both supplemented with fentanyl. Arterial pressure (AP) and heart rate (HR) were measured the day before surgery, prior to and after spinal anaesthesia, thereafter every 5 min over 30 min and every 10 min thereafter until completion of surgery. Hypotension (30% decrease of systolic AP control value was treated with 500 mL of Ringer lactate solution and in case of failure with ephedrine (5-30 mg i.v.). An isolated bradycardia (HR < 60 b.min-1) was treated with atropine (0.5-1 mg i.v.).

Results: Hypotension occurred in two out of 24 patients of the HSG and eight out of 24 of the ISG (P < 0.05). The mean infused volumes of Ringer lactate solution were 387 +/- 218 mL vs 623 +/- 318 mL respectively (P < 0.05). Ephedrine and/or atropine were not required in HSG, however in 7 out of the 24 patients of the ISG. Adverse clinical effects did not occur.

Conclusion: Hypertonic saline prevents efficiently the occurrence of hypotension during spinal anaesthesia. Considering its ease of preparation, the lack of adverse effects, in patients not suffering arterial hypertension or congestive heart failure, and low cost, hypertonic saline is well adapted for use in a developing country, if isotonic solutions are not available.