Total intravenous anesthesia with a propofol-ketamine combination during coronary artery surgery

Anesthesia induction regimens may affect QT interval in cardiac surgery patients: A randomized-controlled trial

Background: The aim of this study was to investigate the effects on QT interval of the propofol-ketamine combination and the midazolam-fentanyl combination in anesthesia induction for cardiac surgery.

Methods: Between September 2020 and June 2021, a total of 9 5 c ardiac s urgery p atients ( 80 m ales, 1 5 f emales; mean age: 57±9.1 years; range, 26 to 76 years) were included. The patients were divided into two groups as Group PK (propofol-ketamine, n=50) and Group MF (midazolam-fentanyl, n=45). The 12-lead electrocardiographic and hemodynamic measurements were performed at three time points: before anesthesia induction, after anesthesia induction, and after endotracheal intubation. The measurements were evaluated with conventional Bazett's formula and a new model called index of cardio-electrophysiological balance.

Results: The evaluated QTc values of 95 patients after anesthesia induction were significantly prolonged with the Bazett's formula and the index of cardio-electrophysiological balance in Group PK (p=0.034 and p=0.003, respectively). A statistically significant QTc prolongation was observed with the index of cardio-electrophysiological balance after laryngoscopy and endotracheal intubation in Group PK (p=0.042). Hemodynamic parameters were also higher in Group PK.

Conclusion: Our study shows that the propofol-ketamine combination prolongs the QTc value determined by the Bazett's formula and the index of cardio-electrophysiological balance model. Using both QTc measurement models, the midazolam-fentanyl combination has no prolongation effect on QTc interval in coronary surgery patients.

Ketamine in adult cardiac surgery and the cardiac surgery Intensive Care Unit: an evidence-based clinical review

Ketamine is a unique anesthetic drug that provides analgesia, hypnosis, and amnesia with minimal respiratory and cardiovascular depression. Because of its sympathomimetic properties it would seem to be an excellent choice for patients with depressed ventricular function in cardiac surgery. However, its use has not gained widespread acceptance in adult cardiac surgery patients, perhaps due to its perceived negative psychotropic effects. Despite this limitation, it is receiving renewed interest in the United States as a sedative and analgesic drug for critically ill-patients. In this manuscript, the authors provide an evidence-based clinical review of ketamine use in cardiac surgery patients for intensive care physicians, cardio-thoracic anesthesiologists, and cardio-thoracic surgeons. All MEDLINE indexed clinical trials performed during the last 20 years in adult cardiac surgery patients were included in the review.

Ketamine Affects In Vitro Differentiation of Monocyte into Immature Dendritic Cells

Background:

Monocytes (MOs) have the unique ability to differentiate into immature dendritic cells (iDCs) (MO→iDC) under the influence of interleukin-4 and granulocyte–monocyte colony-stimulating factor (IL-4&GM-CSF). In this study, the authors investigated the influence of ketamine on the process of MO→iDC.

Methods:

iDCs were cultured from MO obtained from 36 subjects in the presence of IL-4 and GM-CSF and ketamine at 100, 10, and 1 μg/ml for 5 days. In some of the experiments, the authors used nonspecific N-methyl-d-aspartate (NMDA) receptor antagonist MK-801, NMDA, or a neutralizing antibody for transforming growth factor β (TGFβ). The expression of surface markers and functional assays were used to assess the effect of ketamine on IL-4&GM-CSF-stimulated MO. IL-4&GM-CSF-stimulated MO’s supernatants were assessed for cytokine levels.

Results:

Ketamine at 10 μg/ml, and higher concentrations, diminished the expression of CD1a on IL-4&GM-CSF-stimulated MO and retarded both their ability to process DQ ovalbumin and mixed lymphocyte reaction stimulation. The addition of ketamine to IL-4&GM-CSF-differentiated MO resulted in the persistent expression of CD14 and unchanged expression of CD86 and CD206. The phagocytic abilities of IL-4&GM-CSF-differentiated MO were not changed by ketamine. MK-801, a nonselective NMDA agonist, mimicked ketamine’s effect on MO→iDC differentiation. Adding exogenous NMDA to IL-4&GM-CSF-stimulated MO in the presence of ketamine partially restored the level of CD1a+. TGFβ was elevated in supernatants of IL-4&GM-CSF-stimulated MO in the presence of ketamine. Adding neutralizing TGFβ antibody or TGFβR1 blocker (SB431542) resulted in the full recovery of MO→iDC, despite the presence of ketamine.

Conclusions:

Ketamine diminishes the process of MO→iDC in vitro. This is mediated via NMDA-dependent mechanisms and TGFβ.

Ketofol in electroconvulsive therapy anesthesia: two stones for one bird

PURPOSE

Propofol and ketamine have become progressively popular in electroconvulsive therapy (ECT) anesthesia, although propofol shortened seizure duration and ketamine might cause cardiotoxicity, psychotic episodes, and delayed recovery. Ketofol is a combination of ketamine and propofol, and the current study was designed to evaluate the effect of ketamine, propofol, and ketofol on hemodynamic profile, duration of seizure activity, and recovery times in patients undergoing ECT.

METHODS

Ninety patients (44 women, mean age 27.8 ± 7.2 years) in one ECT session were enrolled and randomized to the propofol, ketamine, or ketofol group. Hemodynamic profile duration of seizure activity and recovery times were recorded.

RESULTS

Motor seizure duration in the propofol group was significantly decreased compared to other groups (p < 0.001), whereas spontaneous breathing time in the ketamine group statistically increased compared to the propofol group (p = 0.001), and also eye-opening time (p < 0.001) and obeying-command time (p < 0.001) was significantly increased in the ketamine group compared to other groups. Heart rate (HR) at induction (ketamine 91.2 ± 13.6 vs. propofol 77 ± 13.4 and ketofol 79.9 ± 15.6; p < 0.013; p < 0.08, respectively) was statistically significantly increased in the ketamine group compared to other groups, and HR at the third minute (ketamine 92 ± 12.9 vs. propofol 79.4 ± 9.3 and ketofol 81.5 ± 14.2; p < 0.012, p < 0.048) was also statistically significantly increased in ketamine group compared to other groups.

CONCLUSION

The ketofol 1:1 mixture is associated with longer mean seizure time than propofol, and shorter mean recovery times than ketamine, with better hemodynamic stability, without any important side effects in ECT anesthesia.

Use of ketofol for procedural sedation and analgesia in children with hematological diseases

BACKGROUND

The aim of this study was to evaluate the effectiveness and safety of intravenous ketamine-propofol admixture ("ketofol") in the same syringe for procedural sedation and analgesia in children undergoing bone marrow aspiration.

METHODS

This was a prospective, observational pilot study. Patients aged between 4 and 12 years requiring sedation for bone marrow aspiration were included. Ketofol (1:1 mixture of ketamine 10 mg/mL and propofol 10 mg/mL) was given intravenously in 0.5 mg/kg aliquots each with a 1-min interval and titrated to reach sedation levels of 3 or 4 (Ramsay score). The primary outcome was patient satisfaction with the degree of sedation. Secondary outcomes included injection pain, total sedation time, recovery time, hemodynamic and respiratory parameters, and adverse events.

RESULTS

A total of 20 patients were enrolled in the study. The median total dose of ketofol administered was 1.25 mg/kg each of propofol and ketamine (95%CI 0.77-2 mg/kg). The median score on the visual analog scale was 0 (extremely comfortable) (0-1.5; 95%CI 0.2-2.2). Median recovery time was 23 min (20.5-28 min; 95%CI 17.1-51.2). The incidence of injection pain was 2/20. Two patients had transient diplopia and one child reported dreams. No patients had hypotension, vomiting or required airway intervention.

CONCLUSION

Ketofol provided effective sedation, which was reflected in the high degree of satisfaction recorded by children requiring procedural sedation and analgesia for bone marrow aspiration. We also observed rapid recovery and no clinically significant complications. A large number of patients is required to evaluate and validate these findings.

Experience with a propofol-ketamine mixture for sedation during pediatric orthopedic surgery

BACKGROUND

Various combinations of propofol and ketofol have been described for the provision of procedural sedation in both adults and children. Utilization of 'ketofol' for deep sedation during prolonged pediatric orthopedic procedures has not previously been described.

METHODS

During an orthopedic aid trip, a 1:1 mixture of propofol and ketamine (200 mg of each drawn up to 22 ml) was utilized to provide deep sedation or general anesthesia as an adjunct to regional analgesia for lower limb surgery. Details for 18 patients having a total of 19 procedures were recorded with a record of intraoperative and postoperative parameters including initial bolus doses and infusion rates of ketofol required to produce deep sedation.

RESULTS

Mean operating time was 153.7 min (range 64-241 min). The mean initial bolus dose of ketofol was 0.19 ml·kg(-1) (range 0.1-0.5 ml·kg(-1) ) or 1.7 mg·kg(-1) each of propofol and ketamine (range 0.9-4.5 mg·kg(-1) ). The mean upper limit of the infusion rate required to maintain deep sedation was 0.19 ml·kg(-1) ·h(-1) (range 0.07-0.26 ml·kg(-1) ·h(-1) ) or 1.7 mg·kg(-1) ·h(-1) (range 0.6-2.4 mg·kg(-1) ·h(-1) ) and the mean lower limit of the infusion rate was 0.08 ml·kg(-1) ·h(-1) (range 0.02-0.13 ml·kg(-1) ·h(-1) ) or 0.7 mg·kg(-1) ·h(-1) (range 0.2-1.2 mg·kg(-1) ·h(-1) ). The mean initial bolus dose of ketofol was 0.19 ml·kg(-1) (range 0.1-0.5 ml·kg(-1) ). There were no episodes of hypo- or hypertension or of desaturation. Mean time to eye opening after infusion cessation was 5.1 min (median 2 min; range 0-17 min).

CONCLUSION

Ketofol successfully produced deep sedation for prolonged pediatric orthopedic procedures in conjunction with regional analgesia. Further research to confirm its safety and applicability to a wider range of settings is required.

Ketamine attenuates post-operative cognitive dysfunction after cardiac surgery

BACKGROUND

Post-operative cognitive dysfunction (POCD) commonly occurs after cardiac surgery. Ketamine exerts neuroprotective effects after cerebral ischemia by anti-excitotoxic and anti-inflammatory mechanisms. We hypothesized that ketamine attenuates POCD in patients undergoing cardiac surgery concomitant with an anti-inflammatory effect.

METHODS

Patients randomly received placebo (0.9% saline; n=26) or an i.v. bolus of ketamine (0.5 mg/kg; n=26) during anesthetic induction. Anesthesia was maintained with isoflurane and fentanyl. A nonsurgical group (n=26) was also included as control. Recent verbal and nonverbal memory and executive functions were assessed before and 1 week after surgery or a 1-week waiting period for the nonsurgical controls. Serum C-reactive protein (CRP) concentrations were determined before surgery and on the first post-operative day.

RESULTS

Baseline neurocognitive and depression scores were similar in the placebo, ketamine, and nonsurgical control groups. Cognitive performance after surgery decreased by at least 2 SDs (z-score of 1.96) in 21 patients in the placebo group and only in seven patients in the ketamine group compared with the nonsurgical controls (P<0.001, Fisher's exact test). Cognitive performance was also significantly different between the placebo- and the ketamine-treated groups based on all z-scores (P<0.001, Mann-Whitney U-test). Pre-operative CRP concentrations were similar (P<0.33, Mann-Whitney U-test) in the placebo- and ketamine-treated groups. The post-operative CRP concentration was significantly (P<0.01, Mann-Whitney U-test) lower in the ketamine-treated than in the placebo-treated group.

CONCLUSIONS

Ketamine attenuates POCD 1 week after cardiac surgery and this effect may be related to the anti-inflammatory action of the drug.

The use of "ketofol" (ketamine-propofol admixture) infusion in conjunction with regional anaesthesia

We present four patients in whom a "ketofol" (ketamine 200 mg and propofol 200 mg) infusion was used in conjunction with regional anaesthesia. The patients were considered 'high risk' due to their medical condition or age. The ketofol proved safe and effective in all four cases. Advantages of this technique included analgesia, airway preservation, maintenance of spontaneous respiration, haemodynamic stability and rapid recovery.

Neuropathic pain in dogs and cats: if only they could tell us if they hurt

Neuropathic pain is difficult to diagnose in veterinary patients because they are unable to verbalize their pain. By assuming that neuropathic pain may exist based on the history of events that each patient has experienced, a focused client history and neurologic examination may identify a lesion resulting in persistent or spontaneous pain. Once neuropathic pain is diagnosed, a trial analgesic or acupuncture session(s) should be prescribed with instructions for owners to observe behavior. Dosing of the analgesic can be titrated to the patient's needs while avoiding adverse effects. When a particular analgesic may be ineffectual, an alternate class should be tried. As research into the neurobiologic mechanisms of neuropathic pain continues, specific therapies for its management should eventually appear in the human clinical setting and subsequently be investigated for veterinary clinical use.

A case of refractory intraoperative hypotension treated with vasopressin infusion

A 56-year-old man, treated with an angiotensin II receptor antagonist for hypertension, presented for placement of a cochlear implant during general anesthesia. Intraoperatively, there was profound hypotension that was resistant to decreasing the anesthetic depth, fluid administration, as well as bolus doses of phenylephrine, ephedrine, and epinephrine. Hypotension was eventually successfully treated with a vasopressin infusion (0.06 U/min). Vasopressin may be a useful agent in such scenarios because its effect is not dependent on either adrenergic or angiotensin receptors, both of which may be affected by angiotensin II receptor antagonists.

Effects of Fentanyl and S(+)-ketamine on Cerebral Hemodynamics, Gastrointestinal Motility, and Need of Vasopressors in Patients With Intracranial Pathologies

In neurosurgical patients, opioids are administered to prevent secondary cerebral damage. Complications often related to the administration of opioids are a decrease in blood pressure affording the use of vasopressors and intestinal atonia. One alternative approach to opioids is the application of S(+)-ketamine. However, owing to a suspected elevation of intracranial pressure (ICP), the administration of S(+)-ketamine has questioned for a long time. The aim of the present study was to evaluate ICP, gastrointestinal motility, and catecholamine consumption in neurosurgical patients undergoing 2 different protocols of anesthesia using fentanyl or S(+)-ketamine. Twenty-four patients sustaining traumatic brain injury or aneurysmal subarachnoid hemorrhage received methohexitone plus either fentanyl or S(+)-ketamine to establish a comparable level of sedation. To reach an adequate cerebral perfusion pressure (CPP), the norepinephrine dosage was adapted successively. Enteral nutrition and gastrointestinal stimulation were started directly after admission on the critical care unit. ICP, CPP, and norepinephrine dosage were recorded over 5 days and also the time intervals to full enteral nutrition and first defecation. There was no difference regarding ICP, CPP, and the time period until full enteral nutrition or first defecation between both groups. Patients who underwent analgesia with S(+)-ketamine showed a trend to a lower demand of norepinephrine compared with the fentanyl group. Our results indicate that S(+)-ketamine does not increase ICP and that its use in neurosurgical patients should not be discouraged on the basis of ICP-related concerns.

Evaluation of propofol-ketamine anesthesia for children undergoing cardiac catheterization procedures

The aim of this study was to assess the safety and efficacy of the continuous intravenous administration of a combination of propofol and ketamine for children undergoing cardiac catheterization procedures (CCP). Thirty-two children scheduled for CCP in a university teaching hospital were included in this prospective randomized study. Patients in group 1 (n = 15) were given a combination of propofol (25 microg/kg per minute) and ketamine (25 microg/kg per minute), whereas patients in group 2 (n = 17) received a combination of propofol (25 microg/kg per minute) and ketamine (12.5 microg/kg per minute) for the maintenance of anesthesia. There were no statistically significant differences with age, weight, duration of the procedure, and the number of diagnostic and interventional procedures between the two groups. There was no hemodynamic instability, airway compromise, excessive salivation, or arterial desaturation in either of the two groups. There was more incidence of movements in patients who received less dose of ketamine; however, it did not reach to statistically significant level. The total dose of ketamine used in group 1 was 309.25 +/- 90.97 microg/min, whereas in group 2, it was 148.06 +/- 34.05 microg/min. The time to awakening was significantly less in group 2 (P < 0.05). We conclude that a combination of propofol (25 microg/kg per minute) and two different doses of ketamine (25 and 12.5 microg/kg per minute, respectively) are safe and efficacious for CCP in children. Although the time to awaken was more in patients receiving 25 microg/kg per minute of ketamine compared to those receiving 12.5 microg/kg per minute of ketamine, it was well within acceptable limits.

Revising a Dogma: Ketamine for Patients with Neurological Injury?

We evaluated reports of randomized clinical trials in the perioperative and intensive care setting concerning ketamine's effects on the brain in patients with, or at risk for, neurological injury. We also reviewed other studies in humans on the drug's effects on the brain, and reports that examined ketamine in experimental brain injury. In the clinical setting, level II evidence indicates that ketamine does not increase intracranial pressure when used under conditions of controlled ventilation, coadministration of a gamma-aminobutyric acid (GABA) receptor agonist, and without nitrous oxide. Ketamine may thus safely be used in neurologically impaired patients. Compared with other anesthetics or sedatives, level II and III evidence indicates that hemodynamic stimulation induced by ketamine may improve cerebral perfusion; this could make the drug a preferred choice in sedative regimes after brain injury. In the laboratory, ketamine has neuroprotective, and S(+)-ketamine additional neuroregenerative effects, even when administered after onset of a cerebral insult. However, improved outcomes were only reported in studies with brief recovery observation intervals. In developing animals, and in certain brain areas of adult rats without cerebral injury, neurotoxic effects were noted after large-dose ketamine. These were prevented by coadministration of GABA receptor agonists.

IMPLICATIONS

Ketamine can be used safely in neurologically impaired patients under conditions of controlled ventilation, coadministration of a {gamma}-aminobutyric acid receptor agonist, and avoidance of nitrous oxide. Its beneficial circulatory effects and preclinical data demonstrating neuroprotection merit further animal and patient investigation.

Evaluation of the neuroprotective effects of S(+)-ketamine during open-heart surgery

We compared the effect of S(+)-ketamine to remifentanil, both in combination with propofol, on the neurocognitive outcome after open-heart surgery in 106 patients. A battery of neurocognitive tests was administered before surgery and 1 and 10 wk after surgery. Fourteen patients (25%) in the control group and 10 patients (20%) in the S(+)-ketamine group had 2 or more tests with a cognitive deficit (decline by at least one preoperative SD of that test in all patients) 10 wk after surgery (P = 0.54). Z-scores were calculated for all tests. No significantly better performance could be detected in the S(+)-ketamine group, except for the Trailmaking B test 10 wk after surgery. We conclude that S(+)-ketamine offers no greater neuroprotection compared with remifentanil during open-heart surgery.

IMPLICATIONS

N-methyl-D-aspartic acid receptors play an important role during ischemic brain injury. We could not demonstrate that S(+)-ketamine resulted in greater neuroprotective effects compared with remifentanil during cardiopulmonary bypass procedures when both were combined with propofol.

Propofol-ketamine mixture for anesthesia in pediatric patients undergoing cardiac catheterization

OBJECTIVE

To evaluate the safety of a propofol-ketamine mixture to induce and maintain anesthesia in spontaneously breathing pediatric patents during cardiac catheterization.

DESIGN

Prospective clinical study.

SETTING

Departments of Cardiothoracic Surgery, Anesthesiology, and Pediatric Anesthesiology in a university hospital.

PARTICIPANTS

Forty-five children aged 6 months to 16 years with ASA grade II to III undergoing cardiac catheterization.

INTERVENTIONS

Continuous intravenous infusion of a mixture of propofol (4 mg/mL) and ketamine (2 mg/mL) with spontaneous ventilation. The infusion rate was changed and additional boluses of propofol or/and ketamine were given as needed. Hemodynamic, respiratory, and other variables were recorded during the procedure and recovery.

RESULTS

Mean dose of ketamine was 26 +/- 8.3 microg/kg/min and of propofol, 68.3 +/- 21.7 microg/kg/min. Changes in heart rate and mean arterial pressure of more than 20% from baseline were observed in 4 and 5 patients, respectively. A transient reduction in oxygen saturation because of hypoventilation was observed in 3 patients and responded to oxygen administration and manual assisted ventilation. No other complications were observed.

CONCLUSIONS

The propofol-ketamine mixture is a safe, practical alternative for general anesthesia in pediatric patients undergoing cardiac catheterization.

Cardiovascular effects of propofol alone and in combination with ketamine for total intravenous anesthesia in cats

OBJECTIVE

To compare cardiovascular effects of equipotent infusion doses of propofol alone and in combination with ketamine administered with and without noxious stimulation in cats.

ANIMALS

6 cats.

PROCEDURE

Cats were anesthetized with propofol (loading dose, 6.6 mg/kg; constant rate infusion [CRI], 0.22 mg/kg/min) and instrumented for blood collection and measurement of blood pressures and cardiac output. Cats were maintained at this CRI for a further 60 minutes, and blood samples and measurements were taken. A noxious stimulus was applied for 5 minutes, and blood samples and measurements were obtained. Propofol concentration was decreased to 0.14 mg/kg/min, and ketamine (loading dose, 2 mg/kg; CRI, 23 microg/kg/min) was administered. After a further 60 minutes, blood samples and measurements were taken. A second 5-minute noxious stimulus was applied, and blood samples and measurements were obtained.

RESULTS

Mean arterial pressure, central venous pressure, pulmonary arterial occlusion pressure, stroke index, cardiac index, systemic vascular resistance index, pulmonary vascular resistance index, oxygen delivery index, oxygen consumption index, oxygen utilization ratio, partial pressure of oxygen in mixed venous blood, pH of arterial blood, PaCO2, arterial bicarbonate concentration, and base deficit values collected during propofol were not changed by the addition of ketamine and reduction of propofol. Compared with propofol, ketamine and reduction of propofol significantly increased mean pulmonary arterial pressure and venous admixture and significantly decreased PaO2.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of propofol by CRI for maintenance of anesthesia induced stable hemodynamics and could prove to be clinically useful in cats.