[The influence of the sedation based on remifentanil analgesia on the occurrence of delirium in critically ill patients].

OBJECTIVE: To investigate the influence of the midazolam sedation based on remifentanil analgesia on the occurrence of delirium in critically ill patients in intensive care unit (ICU).

METHODS: A single-center prospective randomized controlled trial was conducted. 140 consecutive critically ill patients admitted to ICU of Peking University People's Hospital, undergoing mechanical ventilation longer than 24 hours, with the need of sedation, from February 2014 to January 2015 were enrolled. They were randomly divided into two groups by computer generated random numbers table, each n = 70. The patients in observation group received midazolam 1 μg x kg(-1) x min(-1) for sedation, and 1 mg/mL remifentanil for analgesia with 0.05 mg/kg intravenous bolus, then continuous infusion of 0.02-0.10 mg x kg(-1) x h(-1). The patients in control group received midazolam for sedation only. The data were recorded as follows: the main indices for observation included the occurrence of delirium and its duration; the second item for observation was consumption of drug for sedation, followed by the mean arterial pressure (MAP) before and after sedation, the time of wake-up, duration of mechanical ventilation, the length of ICU stay, and 28-day fatality rate. The 28-day survival was analyzed by Kaplan-Meier survival curve.

RESULTS: The dosage of remifentanil used in observation group was (98.6 ± 24.9) mg/d, the dosage of midazolam was significantly lower than that of the control group (mg/d: 160.6 ± 33.3 vs. 178.9 ± 43.4, t = 2.829, P = 0.005), the incidence of delirium was obviously lower than that of the control group [22.9% (16/70) vs. 57.1% (40/70), χ2 = 15.700, P < 0.001], and the time of delirium was slightly shorter than that of the control group (hours: 162.9 ± 78.0 vs. 194.8 ± 117.3, t = 0.947, P = 0.348). Among the patients with delirium, the dosage of dexmedetomidine used in observation group was significantly less than that of the control group (mg/d: 0.54 ± 0.11 vs. 0.64 ± 0.14, t = 2.112, P = 0.041). The MAP before sedation was similar as the MAP after sedation in both groups, and there was no significant difference between observation group and control group [mmHg (1 mmHg = 0.133 kPa), before treatment: 84.7 ± 16.2 vs. 89.5 ± 37.7, after treatment: 82.3 ± 10.7 vs. 80.8 ± 13.9, both P > 0.05]. There was no significant difference in the time of waking-up between observation group and control group (hours: 2.3 ± 0.9 vs. 2.4 ± 0.8, t = 0.487, P = 0.627). The duration of mechanical ventilation (hours: 143.4? 138.3 vs. 163.9? 158.9, t = 0.812, P = 0.418), the length of ICU stay (days: 8.8 ± 7.7 vs. 10.0 ± 7.8, t = 0.917, P = 0.361) and 28-day fatality rate [11.4% (8/70) vs. 20.0% (14/70), χ2 = 1.941, P = 0.245] in observation group were slightly lower than those of the control group without significant difference. Kaplan-Meier survival curve showed that the cumulative 28-day survival rate in observation group was slightly higher than that of control group (χ2 = 1.647, P = 0.199) CONCLUSION: Analgesia based on sedation may reduce the occurrence of delirium and its severity, furthermore, even if delirium occurs, it may be less severe.