ABSTRACT
BACKGROUND: Dexmedetomidine, a α2 agonist as an adjuvant in general anesthesia, has anesthetic and analgesic-sparing property. AIMS: To evaluate the effect of continuous infusion of dexmedetomidine alone, without use of opioids, on requirement of sevoflurane during general anesthesia with continuous monitoring of depth of anesthesia by entropy analysis. MATERIALS AND METHODS: Sixty patients were randomly divided into 2 groups of 30 each. In group A, fentanyl 2 mcg/kg was given while in group B, dexmedetomidine was given intravenously as loading dose of 1 mcg/kg over 10 min prior to induction. After induction with thiopentone in group B, dexmedetomidine was given as infusion at a dose of 0.2-0.8 mcg/kg. Sevoflurane was used as inhalation agent in both groups. Hemodynamic variables, sevoflurane inspired fraction (FIsevo), sevoflurane expired fraction (ETsevo), and entropy (Response entropy and state entropy) were continuously recorded. Statistical analysis was done by unpaired student's t-test and Chi-square test for continuous and categorical variables, respectively. A P-value < 0.05 was considered significant. RESULTS: The use of dexmedetomidine with sevoflurane was associated with a statistical significant decrease in ETsevo at 5 minutes post-intubation (1.49 ± 0.11) and 60 minutes post-intubation (1.11 ±0.28) as compared to the group A [1.73 ±0.30 (5 minutes); 1.68 ±0.50 (60 minutes)]. There was an average 21.5% decrease in ETsevo in group B as compared to group A. CONCLUSIONS: Dexmedetomidine, as an adjuvant in general anesthesia, decreases requirement of sevoflurane for maintaining adequate depth of anesthesia.
ABSTRACT
BACKGROUND: Dexmedetomidine, an α2 agonist, when used as an adjuvant in general anaesthesia attenuates stress response to various noxious stimuli, maintains perioperative haemodynamic stability and provides sedation without significant respiratory depression postoperatively. METHODS: Sixty patients were randomly divided into two groups of 30 each. In group A, fentanyl 2 µg/kg and in group B dexmedetomidine were given intravenously as loading dose of 1 µg/kg over 10 min prior to induction. After induction with thiopentone, in group B, dexmedetomidine was given as infusion at a dose of 0.2-0.8 µg/kg. Sevoflurane was used as inhalation agent in both groups. Haemodynamic variables and entropy (response entropy and state entropy) were recorded continuously. Postoperative sedation and recovery were assessed by sedation score and modified Aldrete's score, respectively. RESULTS: Dexmedetomidine significantly attenuates stress response at intubation with lesser increase in heart rate (10% vs. 17%), systolic blood pressure (6% vs. 23%) and diastolic blood pressure (7% vs. 20%) as compared to the control group (P<0.05). Intraoperatively, an average of 8% fall in systolic blood pressure and 8.16% fall in diastolic pressure in the test group as compared to 3.6% rise in systolic and 3.3% in diastolic pressure of the control group was observed. Postoperatively, the test group showed significant sedation at 2 h as compared to the control group (P=0.00) and recovery was better in the control group for the first 2 h post extubation. CONCLUSION: Dexmedetomidine attenuates various stress responses during surgery and maintains the haemodynamic stability when used as an adjuvant in general anaesthesia. Also, the sedative action of dexmedetomidine delays recovery for the first few hours post extubation.
