Effect of low-dose ketamine versus fentanyl on attenuating the haemodynamic response to laryngoscopy and endotracheal intubation in patients undergoing general anaesthesia at the Aga Khan University Hospital, Nairobi
Date of Award
Master of Medicine (MMed)
Anaesthesiology (East Africa)
Background: The use of drugs to attenuate the haemodynamic response to laryngoscopy and endotracheal intubation is the standard of care during elective surgery. Current evidence is conflicting concerning the best agent and optimal dose for this purpose. In the majority of cases, Fentanyl is widely utilized to attenuate haemodynamic responses. Ketamine, an established available drug, has been scarcely studied in this regard at low doses and against varying doses of other common agents.
Objective: The primary objective was to compare the overall occurrence of hypertension and tachycardia immediately pre-intubation (post-induction) until 10 minutes post intubation between the study group receiving fentanyl at 1.0 μg/kg and the other receiving Ketamine at 0.5 mg/kg.
The secondary objectives were to compare the occurrence of post-induction hypotension and the occurrence of neuropsychiatric phenomena during emergence between the two groups.
Primary outcome measure: Increase of Blood Pressure (systolic, mean arterial or diastolic) and Heart Rate >20% from the baseline.
Secondary outcome measures: Decrease in Blood Pressure (post induction) >20% from baseline; Occurrence of neuropsychiatric manifestations.
Study Setting: The Aga Khan University Hospital, Nairobi.
Study Design: A prospective, double blind, superiority, randomized control trial.
Sample size: A sample size of 108 participants, 54 in the Fentanyl arm and 54 in the Ketamine arm.
Study population: ASA I and II patients aged 18-65 years scheduled for theatre for non-emergent surgery.
Anaesthetic Procedure: 108 adult patients were randomly assigned to one of two groups corresponding to the drugs used for induction: (a) Fentanyl (1.0 μg/kg) added to Propofol (2.0 mg/kg) and Cisatracurium (0.2 mg/kg) (F, n = 54) and (b) Ketamine (0.5 mg/kg) added to Propofol (2.0 mg/kg) and Cisatracurium (0.2 mg/kg) (K, n = 54), and haemodynamic responses evaluated by determining heart rate and blood pressure immediately before laryngoscopy and at 2.5, 5, 7.5 and 10 minutes. This was in addition to standard of care.
Data collection: Data was collected using a data collection tool (see appendix). Patients’ baseline characteristics, systolic blood pressure, mean arterial pressure, diastolic blood pressure and heart rate at baseline then at minute 1, 2.5, 5, 7.5 and 10 were recorded.
Results: 108 ASA I and II patients scheduled to undergo elective surgery were included in this study, 54 participants (50%) in the Fentanyl arm and 54 (50%) in the Ketamine arm. Baseline demographic characteristics were similar between the groups. There were more hypertensive episodes in the Ketamine arm (11%) compared to the Fentanyl arm (1.85%), but not achieving statistical significance: Fisher’s exact test, p=0.06. There was no significant difference in the number of episodes of tachycardia between the Ketamine group 7/54 (13%) and the Fentanyl group, 6/54 (11%); x2=0.05, p=0.82. Hypotensive episodes were more common in those who received Fentanyl, 41/54 (76%), compared to Ketamine recipients, 21/54 (39%), X2=16.9, p<0.001. The use of Ketamine was associated with less episodes of hypotension, adjusted odds ratio = 0.18 (95% confidence interval 0.07, 0.45).
Conclusion: We conclude that there is no difference in the occurrence of hypertension with the use Ketamine at 0.5 mg/kg in combination with Propofol at 2.0 mg/kg. In this regard, Ketamine provides a viable alternative to Fentanyl at 1.0 mcg/kg for the purpose of attenuating the pressor response to laryngoscopy and endotracheal intubation. Additionally, our results suggest that Ketamine may protect against post-induction (pre-laryngoscopy) hypotension.
Ongewe, A. (2016). Effect of low-dose ketamine versus fentanyl on attenuating the haemodynamic response to laryngoscopy and endotracheal intubation in patients undergoing general anaesthesia at the Aga Khan University Hospital, Nairobi (Unpublished master's dissertation). Aga Khan University, East Africa.
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