A Cochrane review included eight studies with a total of 254 subjects. In seven studies which reported on urine output, the output (as measured in cc/24 hours) was noted to be greater in patients given continuous infusion with a weighted mean difference (WMD) of 271 cc/24 hour (95%CI 93.1 to 449; p<0.01). Electrolyte disturbances (hypokalemia, hypomagnesemia) were not significantly different in the two treatment groups with a relative risk (RR) of 1.47 (95%CI 0.52 to 4.15; p=0.5). Less adverse effects (tinnitus and hearing loss) were noted when continuous infusion was given, RR 0.06 (95%CI 0.01 to 0.44; p=0.005). Based on a single study, the duration of hospital stay was significantly shortened by 3.1days with continuous infusion WMD -3.1 (95%CI -4.06 to -2.20; p<0.0001) while cardiac mortality was not significantly different in the two treatment groups, RR 0.47 (95% CI 0.33 to 0.69; p<0.0001). Based on two studies, all cause mortality was not significantly different in the two treatment groups, RR 0.52 (95%CI 0.38 to 0.71; p<0.0001). The existing data does not allow definitive recommendations for clinical practice.
Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment) and by imprecise results (few patients and wide confidence intervals).