[Multicenter, triple-blind randomized placebo controlled trial of adjuvant nitrous oxide 50% in oxygen 50%: efficacy for reducing pain and increasing satisfaction in patients treated for renal colic in the emergency department].
Emergencias · 2016-10-01 · Randomised trial
Abstract
OBJECTIVES: To assess the efficacy of a nitrous oxide and oxygen mixture (N2O/O2 50/50) for reducing pain and increasing satisfaction in patients with an initial clinical diagnosis of renal colic in the emergency department. MATERIAL AND METHODS: Multicenter, triple-blind randomized placebo-controlled trial. We randomized 147 patients with a clinical diagnosis of renal colic to an experimental group to receive the N2O/O2 50/50 mixture (n = 70) or a control group to receive 50% oxygen in air (n = 77). Both groups also received conventional analgesia with dexketoprofen plus metamizol and opiates administered sequentially until pain was brought under control; rescue doses of opioids were also available. The endpoints were the reduction in pain intensity expressed on a visual analog scale (VAS) 5 minutes after the start of treatment and the patient's level of satisfaction with treatment on discharge. RESULTS: The mean (SD) reduction in pain 5 minutes after starting analgesic treatment was 1.84 (2.05) VAS points in the intervention group and 1.67 (1.91) in the placebo group. The difference was not significant (P = .603). Neither were between-group differences significant at other pain evaluation times (10, 15, 30, and 60 minutes). Treatment was considered satisfactory ( 9 on a VAS) by 53 of the 70 intervention-group patients (75.7%) and 56 of the 77 (72.7%) placebo-group patients (P = .412). Adverse effects appeared in 33 of the 70 patients (48.5%) who received the N2O/O2 mixture and in 19 patients (24.7%) who received the placebo (P = .003). CONCLUSION: The addition of N2O/O2 50/50 to standard analgesic therapy does not enhance the efficacy of pain control or the satisfaction of patients treated for renal colic in the emergency department.