对于长期机械通气患者的镇静药物选择

Medications for sedation in patients with prolonged mechanical ventilation

To the Editor: In the 2 randomized controlled trials by Dr Jakob and colleagues,1 the authors concluded that among intensive care unit (ICU) patients receiving prolonged mechanical ventilation, dexmedetomidine was noninferior to midazolam and propofol in maintaining light to moderate sedation. In their trials, the target sedation Richmond Agitation-

Sedation Scale (RASS) scores ranged from 0 to −3.However, we noticed that during sedation maintenance, patients receiving dexmedetomidine had higher actual RASS

scores than those receiving midazolam or propofol. That is those receiving midazolam or propofol compared with dexmedetomidine were at a deeper sedation level. In the absence

of a comparable sedation level of medications between groups, the secondary outcome findings, such as nurses’ assessment of arousal, patients’ ability to cooperate with care, and patients’ ability to communicate pain, should be interpreted with caution.

The ideal sedative agent would have rapid onset of action,be effective at providing adequate sedation, allow rapid recovery after discontinuation, be easy to administer, lack drug accumulation, have few adverse effects, interact minimally with other drugs, and be inexpensive.2 None of the sedatives and analgesics currently in use can meet all of these criteria, although many of them have some of the desirable characteristics. Maintenance of effective sedation and analgesia in mechanically ventilated patients for a prolonged period can be difficult, especially when a single drug is used.In this study, drug discontinuation due to lack of efficacy occurred in some patients in each group. Optimal pharmacologic therapy for sedation in patients receiving prolonged mechanical ventilation usually requires the use of a combination of sedatives, analgesics, and antipsychotic agents.4 For example, midazolam and propofol are common agents used for sedation, often with an opioid drug such as fentanyl or remifentanil.Furthermore, different clinical situations require a comprehensive understanding of all the medications available for ICU sedation and analgesia. A recommended practice is to use a benzodiazepine or propofol with opioid drugs for sedation and analgesia and then switch to dexmedetomidine to attempt extubation. This regimen has been shown to enable reduction of the dose of sedatives and may facilitate extubation.5 Thus, we believe that comparing sedation regimens using a single drug in patients with prolonged mechanical ventilation may have only limited practical value.

Fu S. Xue, MD

Xu Liao, MD

Yu J. Yuan, MD