Comparison of ketamine with fentanyl as co-induction in propofol anesthesia for short surgical procedures

Effect of low-dose ketamine versus fentanyl on attenuating the haemodynamic response to laryngoscopy and endotracheal intubation in patients undergoing general anaesthesia: a prospective, double-blinded, randomised controlled trial

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

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, to compare the occurrence of post-induction hypotension and the occurrence of neuropsychiatric phenomena during emergence between the two groups.

METHODS

One hundred and eight ASA I and II patients aged 18-65 years scheduled for elective surgery under general anaesthesia were randomized into two groups: Control group: received fentanyl 1.0 µg/kg intravenously. Intervention group: received ketamine 0.5 mg/kg intravenously. General anaesthesia was standardized in both groups. The patients and physicians administering anaesthesia were blinded to the study. Haemodynamic responses were evaluated by determining heart rate and blood pressure immediately before laryngoscopy and at 2.5, 5, 7.5 and 10 minutes. Neuropsychiatric phenomena were assessed upon recovery from anaesthesia.

RESULTS

One hundred and eight 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, based upon findings in this study group, 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 µg/kg for attenuating the pressor response to laryngoscopy and endotracheal intubation. Additionally, our results suggest that ketamine may protect against post-induction (pre-laryngoscopy) hypotension.

Effect of Etomidate Versus Combination of Propofol-Ketamine and Thiopental-Ketamine on Hemodynamic Response to Laryngoscopy and Intubation: A Randomized Double Blind Clinical Trial

BACKGROUND

Laryngoscopy and intubation frequently used for airway management during general anesthesia, is frequently associated with undesirable hemodynamic disturbances.

OBJECTIVES

The aim of this study was to compare the effects of etomidate, combination of propofol-ketamine and thiopental-ketamine as induction agents on hemodynamic response to laryngoscopy and intubation.

PATIENTS AND METHODS

In a double blind, randomized clinical trial a total of 120 adult patients of both sexes, aged 18 - 45 years, scheduled for elective surgery under general anesthesia were randomly assigned into three equally sized groups. Patients in group A received etomidate (0.3 mg/kg) plus normal saline as placebo. Patients in group B and C received propofol (1.5 mg/kg) plus ketamine (0.5 mg/kg) and thiopental sodium (3 mg/kg) plus ketamine (0.5 mg/kg), respectively for anesthesia induction. Before laryngoscopy and tracheal intubation, immediately after, and also one and three minutes after the procedures, hemodynamic values (SBP, DBP, MAP and HR) were measured.

RESULTS

A repeated measurement ANOVA showed significant changes in mean SBP and DBP between the time points (P < 0.05). In addition, the main effect of MAP and HR were statistically significant during the course of study (P < 0.05). Furthermore, after induction of anesthesia, the three study groups had significantly different SBP, DBP and MAP changes overtime (P < 0.05). However, HR changes over time were not statistically significant (P > 0.05). Combination of propofol-ketamine had superior hemodynamic stability compared to other induction agents.

CONCLUSIONS

Combination of propofol-ketamine may be recommended as an effective and safe induction agent for attenuating hemodynamic responses to laryngoscopy and intubation with better hemodynamic stability. Although, further well-designed randomized clinical trials to confirm the safety and efficacy of this combination, especially in critically ill patients or patients with cardiovascular disease, are warranted.

Ketamine: Current applications in anesthesia, pain, and critical care

Ketamine was introduced commercially in 1970 with the manufacturer's description as a "rapidly acting, nonbarbiturate general anesthetic" and a suggestion that it would be useful for short procedures. With the help of its old unique pharmacological properties and newly found beneficial clinical properties, ketamine has survived the strong winds of time, and it currently has a wide variety of clinical applications. It's newly found neuroprotective, antiinflammatory and antitumor effects, and the finding of the usefulness of low dose ketamine regimens have helped to widen the clinical application profile of ketamine. The present article attempts to review the current useful applications of ketamine in anesthesia, pain and critical care. It is based on scientific evidence gathered from textbooks, journals, and electronic databases.

The effects of propofol-midazolam-ketamine co-induction on hemodynamic changes and catecholamine response

STUDY OBJECTIVE

To compare the clinical efficacy of co-induction with propofol-midazolam-ketamine with etomidate as the sole induction agent.

DESIGN

Prospective, double-blinded, randomized controlled trial.

SETTING

Operating room of a university hospital.

PATIENTS

60 ASA physical status 1 and 2 patients scheduled for limited elective surgery requiring general anesthesia.

INTERVENTIONS

Patients were randomized to two groups to receive etomidate 0.3 mg/kg (single-drug group) or propofol 0.6 mg/kg + ketamine 0.8 mg/kg + midazolam 0.06 mg/kg (three-drug group).

MEASUREMENTS

Hemodynamic responses (systolic and diastolic blood pressure, and mean arterial pressure) were examined at baseline and at one, three, and 5 minutes after tracheal intubation. Plasma catecholamine levels were measured at baseline, one, and 5 minutes after tracheal intubation.

MAIN RESULTS

Heart rate (HR) changes differed significantly between the two groups at three minutes (P = 0.01) and 5 minutes (P = 0.00) after tracheal intubation. However, the HR increase in the three-drug group was in the acceptable range. Percentage changes of epinephrine level differed between the two groups at 5 minutes after tracheal intubation (P = 0.03).

CONCLUSIONS

The higher norepinephrine/epinephrine ratio noted in the single-drug group may be implicated in lower adrenal sympathetic activity. Propofol-midazolam-ketamine co-induction may be used instead of etomidate for anesthesia induction in patients with hemodynamic instability.

Low-dose ketamine as a potential adjuvant therapy for painful vaso-occlusive crises in sickle cell disease

The hallmark of sickle cell disease (SCD) is the acute painful vaso-occlusive crisis (VOC). Among SCD patients, vaso-occlusive pain episodes vary in frequency and severity. Some patients rarely have painful crises, while others are admitted to the hospital multiple times in a year for parenteral analgesics. Opioids are the mainstay of therapy for SCD-related pain. However, a subset of patients report continued pain despite escalating doses of opioids. Tolerance and opioid-induced hyperalgesia (OIH) have been considered as possible explanations for this phenomenon. The activation of the N-methyl-d-aspartate (NMDA) receptor has been implicated in both tolerance and OIH. As a NMDA receptor agonist, ketamine has been shown to modulate opioid tolerance and OIH in animal models and clinical settings. Low-dose ketamine, by virtue of its NMDA receptor agonist activity, could be a useful adjuvant to opioid therapy in patients with refractory SCD-related pain. Based on limited studies of adjuvant ketamine use for pain management, low-dose ketamine continuous infusion appears safe. Further clinical investigations are warranted to fully support the use of low-dose ketamine infusion in patients with SCD-related pain.