Analgesic sparing effects of Dexmedetomidine in surgical intensive care patients

Background: Dexmedetomidine (Dex) is a sedative agent with analgesic property. A recent review of the literature has shown clear advantages over the traditional sedation namely lesser respiratory depression, less delirium, better sedation, analgesia, organ protection and anti-shivering effect. Optimal sedation in critically ill patients is of vital importance, under sedation will raise work of breathing and causes adverse hemodynamic effects. Whereas over sedation will lead to increased number of imaging studies and higher morbidity and mortality. The aim of our study was to investigate the efficacy of dexmedetomidine (Dex), its use in intubated patients and post-extubation period, rescue sedation, safety and analgesic sparing effect in critically ill surgical patients. Patients and Methods: All patients sedated with dexmedetomidine (Dex) in the surgical intensive unit of a tertiary healthcare facility were included prospectively in the study. Patients' demographic data, diagnosis, surgical interventions, traditional sedation, Dex dosage and days, post-extubation Dex use, general adverse effects, adverse effects associated with lower or higher Dex doses, analgesic, and rescue sedation requirements were recorded. Patients were intubated and ventilated, the initial dose of Dex infusion was 0.5 mcg/kg/hr along with either fentanyl or remifentanil infusion. Dex infusion was titrated to keep the Ramsay sedation score of 3 to 4. Analgesia was titrated according to the NRS (numeric rating scale) in extubated patients and the Critical-Care Pain Observation Tool (CPOT) score in intubated patients. The infusion of fentanyl and remifentanil were titrated and decreased according to the CPOT score. Some of the patients extubated required continuation of the Dex infusion in the post-extubation period to maintain analgesia and to keep them calm.
Chi-square test was performed to compare among the groups. P-value ≤ 0.05 was considered as statistically significant. Results: A total of 428 patients were enrolled in the study. The majority of patients were male (73.3%). The most common diagnosis was acute abdomen and frequently the performed surgery was laparotomy (28.9%) (a). The duration of Dex treatment ranged from 2 to 28 days; the most commonly used dose was 0.5 to 1.4 μg/kg/hours (b). Seventy-eight percent (78%) of patients required Dex in the post-extubation period at a dose of 0.2 μg /kg/hours. There was significant reduction in the analgesic requirements in the post-Dex period (p < 0.001) ((a)). Adverse effects such as bradycardia 6.1%, hypertension 4% and hypotension 1.6% were observed () and there was no significant difference in lower and higher dose of Dex and occurrence of adverse effects (p < 0.82). Patients administered a higher dose of Dex required significantly higher rescue traditional sedation (p < 0.01) ((b)). Conclusion: We used dexmedetomidine in different surgical critical patients. The occurrence of adverse effects such as bradycardia, hypotension and hypertension were comparable to that mentioned in the literature. There was a significant analgesia sparing effect of dexmedetomidine. We continued Dex in the post-extubation period and the effective dose used was 0.2 mcg/kg/hour. There was no significant difference in occurrence of adverse effects with lower and higher range of Dex. The patients on a higher dose of Dex needed more rescue traditional sedation.