[Comparison of sedative effect of dexmedetomidine and midazolam for post-operative patients undergoing mechanical ventilation in surgical intensive care unit].

OBJECTIVE: To study sedative effect and safety of dexmedetomidine and midazolam for post-operative patients undergoing mechanical ventilation(MV) in surgical intensive care unit(SICU).

METHODS: Two hundred cases of post-operative patients undergoing MV with tracheal intubation in SICU were enrolled and divided into two groups by random numerical table method. They were treated either with midazolam (98 cases) or dexmedetomidine (102 cases). In both groups fentanyl was given intravenously continually for analgesia. The amount of fentanyl was adjusted according to Prince-Henry analgesic score to keep on 1-2 analgesic score; the dose of sedation was regulated by Riker sedative and restless score (SAS) maintain 2-4 sedative score. During the course, parameters of the ventilator, electrocardiogram, heart rate(HR), blood pressure, respiratory rate, pulse oxygen saturation (SpO(2)), blood gas analysis were observed and registered continuously. The amount of the drug, duration of MV, and incidence of side-effects such as hypotension, bradycardia, delirium, nausea, etc. were recorded in two groups.

RESULTS: In all the patients in two groups taking dexmedetomidine or midazolam expected sedative and analgesia scores were obtained. In the group with dexmedetomidine, the patients were aroused easier with adequate sedation, and when compared with the group with midazolam, dose of fentanyl (μg× kg(-1)×h(-1) ) was significantly smaller (0.23±0.13 vs. 0.41±0.12, P<0.01), duration of MV (hours) was clearly shorter (7.20±6.29 vs. 12.44±8.96, P<0.01), the rates of hypotension (27.45% vs. 11.22%) and bradycardia (24.51% vs. 10.20%) were significantly higher (both P<0.05), the rate of delirium was clearly lower (3.92% vs. 31.63%, P<0.01), the rate of nausea showed a slight decrease (9.80% vs. 11.22%, P>0.05). The patients in the group with dexmedetomidine were divided into two subgroups of hypotension and non-hypotension. The quantity of blood loss during operation (ml/kg), amount of fluid infusion during operation (ml× kg(-1)×h(-1) ), blood lactic acid concentration (mmol/L) on the day of surgical operation and the 1st day post-operative showed no significant difference between these subgroups (quantity of blood loss on the day of surgical operation: 12.79±12.13 vs. 13.52±11.62; amount of fluid infusion during surgical operation: 11.91±4.59 vs. 13.09±7.05;blood lactic acid concentration on the day of operation: 1.88±1.07 vs. 1.71±0.87, blood lactic acid concentration on the 1st day post-operative:1.43±0.98 vs. 1.37±0.79, all P>0.05).

CONCLUSION: Sedative effect of dexmedetomidine is satisfactory for patients undergoing MV after operation, with the property of easier arousal, lower delirium rate, and it helps to shorten the duration of MV with reduction the dosage of fentanyl by 50%. However, it is necessary to enhance observation in order to prevent and control hypotension and bradycardia.