Intraoperative Ketamine Infusion Research Articles

The effect of intraoperative low-dose ketamine versus dexmedetomidine infusion on postoperative bowel recovery in patients undergoing gastrointestinal malignancy surgeries: Placebo-controlled, randomized trial

Abstract Background and Aims: No studies have compared the effects of ketamine and dexmedetomidine on bowel recovery. We evaluated the effects of intraoperative low-dose ketamine or dexmedetomidine infusion on postoperative bowel recovery in patients undergoing gastrointestinal (GI) malignancy surgeries. Material and Methods: This placebo-controlled, randomized study was carried out in 84 American Society of Anesthesiologists II patients, aged 18–70 years, of either gender, undergoing elective open GI malignancy surgeries. Patients received intraoperative infusion of ketamine @ 0.1 mg kg-1 h-1 (KET), dexmedetomidine @ 0.25 μg kg-1 h-1 (DEX), or normal saline (placebo). Primary outcome was the time to first flatus and/or stool. Secondary outcomes included time to extubation, total analgesic requirement, postoperative pain scores, time to feeds, duration of intensive care unit (ICU) and hospital stay, and the incidence of adverse events. Continuous data were analyzed by the one-way analysis of variance (ANOVA) or the Kruskal–Wallis test. Categorical data were analyzed by the Chi-square test or the Fisher’s exact test. Results: Median time to passage of flatus and/or stool was 3 [interquartile range (IQR) 2–3] days in the KET group, 2 [IQR 2–3] days in the DEX group, and 2 [IQR 2–3] days in the placebo group (P = 0.53 for placebo vs. KET, 0.81 for placebo vs. DEX, and 0.99 for KET vs. DEX). Pain scores and analgesic consumption were significantly less in the intervention groups versus placebo (P < 0.001). No difference was seen in other secondary outcomes. Conclusion: Low-dose ketamine or dexmedetomidine did not result in early bowel recovery despite lower pain scores and opioid consumption in patients undergoing open GI malignancy surgeries. Key Message: What is known: Ketamine and dexmedetomidine may promote bowel recovery by improving analgesia and decreasing opioid usage.Main findings: This randomized controlled trial found no evidence of earlier bowel recovery with ketamine or dexmedetomidine versus placebo despite lower pain scores and analgesic consumption in the ketamine and dexmedetomidine groups.

Efficacy of intraoperative subanaesthetic dose of ketamine on post-operative analgesia for patients undergoing single level lumbar discectomy under general anesthesia: A placebo control randomized clinical study

Background: Sub-anesthetic ketamine is becoming increasingly popular for opioid sparing analgesic properties. Aims and Objectives: This study was done to determine the efficacy of intraoperative infusion of sub-anesthetic dose of ketamine on post-operative analgesia in single level lumbar discectomy surgeries. Materials and Methods: A prospective, randomized, and control study was carried on 60 patients of American Society of Anesthesiologists I and II aged between 18 and 65 years undergoing single level lumbar discectomy under general anesthesia. After induction of anesthesia, Group A received Ketamine 0.3 mg/kg intravenous (IV) bolus followed by infusion at 4 μg/kg/min and Group B received 0.9% saline bolus dose of similar volume and infusion was started at similar rate. Post-operative pain relief, opioid sparing effect, and side effects if any were recorded. Results: There was significant difference (P<0.001) in post-operative Numeric Rating scores for initial 6 h in Group A patients compared to Group B and prolonged duration of analgesia (8.5 vs. 4.25 h) along with reduced postoperative tramadol consumption. Conclusion: In lumbar spine discectomy, intraoperative ketamine infusion at sub-anesthetic doses produces more effective post-operative analgesia along with opioid sparing effect without any side effects.

Justification of the expediency of using harmless analgesia in bariatric surgery: prospective randomized study

BACKGROUND: The presence of various comorbid conditions in patients with obesity increases operational risk, and high sensitivity to sedatives and opioid drugs can contribute to their aggravation.
 OBJECTIVE: To compare and evaluate two methods of perioperative analgesia, namely, multimodal without opioid and non-opioid when performing longitudinal gastric resection for patients with morbid obesity using the enhanced recovery after surgery protocol.
 MATERIALS AND METHODS: A prospective randomized study of patients with morbid obesity was conducted. Depending on the type of analgesic component of anesthesia, the patients are divided into two groups. In both groups, low-flow desflurane inhalation was used; in group 1 (n=30), the technique of non-opioid analgesia was used, which included intraoperative infusion of ketamine, dexmedetomidine, lidocaine, and magnesium sulfate. In group 2 (n=30), traditional combined anesthesia using fentanyl was administered. In the postoperative period, the infusion of the above drugs continued for 10 h in group 1. Central and peripheral hemodynamic parameters, and the depth of anesthesia were studied, and TOF-monitoring was carried out. Postoperative rehabilitation was assessed based on the time of extubation, achievement of 13 points on the PARS scale, first getting up on ones feet, appearance of overstrain, and gas discharge. Postoperative analgesia was assessed on a 10-point visual analog scale, and anesthesia-related complications were recorded.
 RESULTS: Surgical intervention under low-flow inhalation anesthesia based on desflurane in combination with multimodal opioid-free analgesia reduced the need for opioid analgesics intraoperatively (in group 1, the fentanyl dose was 0.2 [01; 0.2] mg; in group 2 0.4 [0.3; 0.5] mg; p=0.002), provided less fluctuation of intraoperative hemodynamic parameters (AvBP: stage 1: group 1 102 [100; 103]; group 2 102 [98; 105], p=0.96; stage 2: group 1 93 [90; 95]; group 2 96 [93; 99], p=0.003; stage 3: group 1 95 [95; 97]; group 2 100 [96; 102], p 0.001; stage 4: group 1 95 [92; 97]; group 2 98 [98; 101], p 0.001; CI stage 1: group 1 492.2; group 2 49.52.2, p=0.39; stage 2: group 1 44.42; group 2 44.62.1, p=0.26; stage 3: group 1 45.52.11; group 2 50.62.8, p=0.001; stage 4: group 1 44.52.1; group 2 48.82.5 p 0.001), and contributed to a lower level of pain and faster rehabilitation. In addition, anesthesia-related complications such as postoperative nausea and vomiting, hypoxemia, and dysphoria were less frequently recorded.
 CONCLUSION: The use of multimodal non-opioid analgesia contributes to a lesser fluctuation in hemodynamic parameters, a low level of postoperative pain, early activation of patients and restoration of peristalsis, and a decrease in the number of postoperative complications in patients who underwent longitudinal gastric resection for morbid obesity.

Single-Center Retrospective Comparison of Opioid-Based and Multimodal Analgesic Regimens in Adult Cardiac Surgery

To compare the outcomes of 2 multimodal analgesic regimens with an opioid-based one. A 2-stage, retrospective study. A large tertiary-care facility. Adult cardiac surgical patients. Patients received one of three regimens: opioid-only or 2 multimodal regimens. The opioid regimen included intraoperative fentanyl and patient-controlled analgesia pumps.Multimodalregimen 1 included preoperative extended-release oxycodone, intraoperative ketamine infusion, and postoperative morphine suppository. Multimodal regimen 2 included intraoperativemethadone and dexmedetomidineinfusion. Outcomes measured included opioid use, pain scores, time to tracheal extubation, postoperative antiemetic use as a surrogate marker for postoperative nausea and vomiting (PONV), age, sex, surgical procedure(s),body mass index, time to first bowel movement, intensive care unit length of stay (LOS), and hospital LOS. Intraoperative median oral morphine equivalents(OMEs) declined from 425 mg (314, 518) to 150 mg (75, 150) and 230 mg (160, 240), p < 0.001, in multimodal regimens 1 and 2, respectively, compared with the opioid-only regimen. Predischargeopioid usewas reduced from a median OME of 7.5 mg (0, 22.5) to 5 mg (0, 22.5) and 0 mg (0, 15.0), p < 0.001, in multimodal regimens 1 and 2, respectively. Pain scores were reduced in the multimodal regimen 2 for hours 0 to 6 (estimated difference=-1.5, 95% CI -1.8 to -1.2, p < 0.001) compared with the opioid-only regimen. The PONV treatment was reduced in multimodal regimen 1 versus the opioid-based or multimodal regimen 2 (53% v 64% and 62%), and time to tracheal extubationwas clinically equivalent across all regimens: 4.2 (2.8, 6.0), 3.6 (2.3, 5.7), and (3.0, 6.2) hours for the opioid and multimodal regimens 1 and 2, respectively. Multimodal analgesic regimens, particularly when incorporating methadone and dexmedetomidine, significantly reduced total and predischarge opioid use in cardiac surgical patients.

A comparative study of clinical effects and recovery characteristics of intraoperative dexmedetomidine infusion with ketamine versus fentanyl as adjuvants in general anaesthesia.

Intraoperative dexmedetomidine infusion decreases the concurrent anaesthetic and analgesic requirement. However, because of slow onset and offset, it is often used with other drugs. Opioids have a depressant effect on the cardiorespiratory system while ketamine has the opposite pharmacodynamics. Hence, it was hypothesised that ketamine will have a better intraoperative haemodynamic profile compared to fentanyl. This study compared the clinical effects and recovery characteristics of ketamine versus fentanyl when used as an adjuvant along with dexmedetomidine infusion intraoperatively. A total of 80 patients (18-60 years) undergoing major surgeries were divided into two groups: Group (D + K) received an intraoperative infusion of ketamine 0.5 mg/kg/h, while group (D + F) received fentanyl 0.5 μg/kg/h along with intravenous dexmedetomidine 0.5 μg/kg/h. Intraoperative heart rate (HR), mean blood pressure, and oxygen saturation were recorded at 0 min, 10 min of induction, and thereafter every 30 min throughout the procedure. Ramsay sedation score (RSS) and visual analogue scale (VAS) score were measured at the end of the surgery, at 2 hours, 4 hours, and 6 hours. Reduction in HR and mean blood pressure was more with a tendency of developing hypotension in the fentanyl group compared to the ketamine group. Post-anaesthesia care unit (PACU) stay, need for muscle relaxant and VAS score for pain were also significantly lesser in the ketamine group. Dexmedetomidine with ketamine provided better haemodynamic stability and reduced PACU stay compared to dexmedetomidine with fentanyl.

Efficacy of intraoperative magnesium sulfate versus ketamine on emergence agitation in pediatric patients under sevoflurane anesthesia: a randomized clinical trial

BackgroundOver the years, sevoflurane has been proven to be the most effective inhalational anesthetic for induction and maintenance of general anesthesia in pediatrics. However, one of the downsides of utilizing sevoflurane anesthesia in pediatrics is emergence agitation (EA). A variety of drugs have been evaluated for prophylaxis against the occurrence of EA. Both magnesium and ketamine were evaluated in controlling this phenomenon; however, the usefulness of using intraoperative magnesium and ketamine infusions in preventing EA is still debatable.MethodsFifty-two children aged 4–7 years who were having elective lower abdominal or pelvic surgeries under sevoflurane anesthesia were enrolled then allocated randomly into one of two groups (n = 26 each). The magnesium group (M) included 26 patients who received intravenous (IV) loading dose of magnesium 15 mg/kg before the surgical incision followed by IV infusion 10 mg/kg/h over the duration of surgery, while the ketamine group (K) included 26 patients who received an IV loading dose of ketamine 1 mg/kg before the surgical incision, then IV infusion 1 mg/kg/h over the duration of surgery. For each patient, the agitation score (Pediatric Anesthesia Emergence Delirium [PAED] scale) and pain score, as well as the time to endotracheal tube (ETT) removal, regain of mental orientation, and transfer from the post-anesthesia care unit (PACU) to ward were all documented.ResultsIntraoperative magnesium sulfate infusion showed a lower PAED score on immediate arrival to PACU than intraoperative ketamine infusion, with less time to tracheal extubation, recovery of mental orientation, and discharge from PACU with a P value below 0.001, while there was no statistical significance between both groups as regards PAED score after 30 min in PACU, pain score, or perioperative vital data.ConclusionsMagnesium sulfate was found superior to ketamine in lowering the severity of the postoperative agitation in pediatric patients undergoing abdominal or pelvic surgeries under sevoflurane anesthesia. Also, patients restored their consciousness and mental orientation faster in the magnesium group compared to ketamine. This has increased the PACU stay in the ketamine group.

Opioid-free anesthesia versus opioid-inclusive anesthesia for breast cancer surgery: a retrospective study

BackgroundBreast cancer surgery is usually managed using opioid-inclusive anesthesia (OIA), although opioids are associated with several adverse events, including nausea, vomiting, and constipation. Multimodal opioid-free anesthesia (OFA) has been introduced to reduce the incidence of these side effects. In this single-center retrospective study, we investigated whether ketamine, combined with magnesium and clonidine, could effectively control postoperative pain in patients undergoing quadrantectomy, while reducing postoperative nausea and vomiting (PONV).ResultsA total of 89 patients submitted to quadrantectomy were included and divided into an OFA group (38 patients) and an OIA group (51 patients) according to the received anesthetic technique. Analgesia in the OIA group was based on an intraoperative infusion of remifentanil, and analgesia in the OFA consisted of an intraoperative infusion of ketamine and magnesium sulfate. Postoperative pain in both groups was managed with nonsteroidal anti-inflammatory drugs (NSAIDs) and paracetamol. Postoperative pain, assessed with the numeric rating scale (NRS), requirements for additional analgesics, the incidence of PONV, and patient satisfaction evaluated using a QoR-40 questionnaire were compared between the two groups. Levels of pain at 30 min and 6, 12, and 24 h after surgery; number of paracetamol rescue doses; and the incidence of PONV were lower in the OFA group (p <0.05). Patient satisfaction was comparable in the two groups.ConclusionsA combination of ketamine, magnesium, and clonidine could be more effective than opioid-based analgesia in reducing postoperative pain and lowering PONV occurrence after quadrantectomy for breast cancer.

Inkk Trial .Çô Intraoperative ketamine for perioperative pain management following total knee endoprosthetic replacement in oncology: a double-blinded randomized trial

BackgroundThere has been a growing interest in the use of ketamine following orthopedic surgeries. We hypothesized that low dose intravenous ketamine during surgery would help in mobilization following total knee replacement (TKR) in oncology patients as assessed by the timed to up and go (TUG) test at 72.áhours post-surgery. Our secondary objectives were to compare the opioid requirement at the end of 72.áhours, pain scores, satisfaction with pain management, adverse effects, range of joint movement achieved in the post-operative period and the functional recovery at the end of 1 month. MethodsAfter the ethics commitee approval, registration of the trial with the Clinical Trial Registry - India (CTRI), and informed consent, this double-blinded trial was conducted. Using computer generated randomization chart, an independent team randomized the patients into ketamine group which received at induction, a ketamine bolus dose of 0.5.ámg.kg-1 before the incision followed by 10.á..g.kg-1min-1 infusion which was maintained intraoperatively till skin closure and the saline group received an equivalent volume of saline. Postoperatively, patient controlled morphine pumps were attached and the pain score with morphine usage were recorded for 72.áhours. The TUG tests and range of motion were assessed by the physiotherapists until 72.áhours. ResultsFifty-two patients were enrolled in the trial. Demographics were comparable. No significant intraoperative hemodynamic changes and post-operative adverse events were noted between the groups. A decrease in the TUG test, along with decreased opioid usage with a better range of movements was noted in the ketamine group, but this was not statistically significant. Day of discharge, patient satisfaction score, and functional recovery assessed by Oxford Knee Score (OKS) were comparable between the groups. ConclusionIn conclusion, low dose intraoperative ketamine infusion does not provide clinical benefit in perioperative pain management and postoperative rehabilitation following total knee endoprosthetic replacement in oncology.

Low dose intraoperative ketamine infusion with multilevel paravertebral block for pain after video-assisted thoracic surgery: a randomized-controlled study.

Intraoperative low-dose ketamine infusion has been reported to be an effective adjuvant to opioids for postoperative pain control without major side effects, but it has not been tested in video-assisted thoracic surgery (VATS). The aim of this study was to examine the effect of low-dose intraoperative intravenous ketamine infusion on 24-hour morphine requirement and acute postoperative pain following VATS for lung resection. This study was a single center, randomized, double-blind, placebo-controlled study. Thirty-two patients undergoing elective VATS for lung resection in a university hospital were included. Patients were randomly allocated (1:1 ratio) to receive either intraoperative low-dose ketamine (0.2 mg/kg/h) or normal saline infusion starting from intubation to the beginning of chest closure. All patients received multilevel thoracic paravertebral block (TPVB) and morphine was administered postoperatively via the patient-controlled analgesia pump using the same protocol. Time to first analgesia, postoperative cumulative morphine doses at 10, 30 minutes, and the consecutive 1, 2, 6, 12, 18, and 24 hours were recorded. Pain intensity during rest and deep breathing were also assessed by numeric rating scale (NRS) score at 1- and 24-hour postoperatively. There was no significant difference in median (P25, P75) cumulative 24-hour morphine requirement between the ketamine and the control groups [15 (5.5, 29.5) vs. 22.5 (15.3, 40.8) mg, P=0.090]. Patients in ketamine group had significantly longer median pain free time than the control group (27 vs. 2 minutes, P=0.006). No difference in overall NRS score at rest or during deep breathing at 1- and 24-hour postoperatively was demonstrated (P=0.861). Intraoperative low dose ketamine infusion in addition to TPVB does not reduce postoperative morphine consumption or pain intensity but may prolong pain free time in patients undergoing VATS for lung resection.

Acute Effects of Ketamine Infusion on Postoperative Mood Scores in Patients Undergoing Dilation and Curettage: A Randomized Double-Blind Controlled Study.

Background Emotional and psychological effects following abortion are more common than physical side effects and can range from mild regret to more serious complications such as depression. In the last decade, it has been suggested that low dose of ketamine is a fast-acting antidepressant. Purpose The aim of this study was to investigate the impact of intraoperative ketamine infusion on postoperative mood score in patients undergoing Dilation and Curettage (D&C) under spinal anesthesia. We hypothesized that a single low-dose administration of ketamine infusion during D&C surgery can improve mood scores in the immediate postoperative period. Methods A prospective, randomized, double-blind, parallel-group, placebo-controlled trial. The study included a total of 60 patients, ≥18 years, physical status ASA II, with up to 12-week gestation undergoing elective D&C surgery. Patients were divided randomly into a ketamine group (group K) and a control group (group C). In group K, 0.4 mg/kg ketamine was given as a continuous infusion over 20 min intraoperatively. Main Outcome Measure. Profile of Mood States (POMS) was recorded preoperatively and 2 hours postoperatively. Results There were no differences in preoperative POMS between the two groups. Mean postoperative POMS of group K was lower than that of group C indicating mood improvement. Ketamine group patients showed higher sedation score and increased, although self-limiting, psychedelic phenomena than the control group. Conclusion Observed data here support an acute effect of ketamine on mood but any further claim will be speculative. Further future studies exploring postoperative mood scores after 24 hours post-infusion are needed. This trial is registered with PACTR201907779292947.

Methadone and Ketamine: Boosting Benefits and Still More to Learn.

Methadone and Ketamine: Boosting Benefits and Still More to Learn.

The effect of intraoperative magnesium sulfate and ketamine infusion on post-operative pain in open gynecological surgeries

Background:besides an opioid analgesic, Multimodal analgesia using a non-opioid analgesic, in atrial to decrease opioid use and toincrease postoperative pain control. Objectives:To compare the effect of intra-operative infusion of ketamine and magnesium sulphate in open gynecological surgeries on post-operative pain, total morphine consumption, post-operative nausea, and vomiting inQena university hospitals. Patients and method(s):A prospective study. Conducted in Qena university hospital, South Valley University, Qena, Egypt. The study was conducted on fifty patients (ASA I or II) scheduled for open gynecological surgeries under general anesthesia: group A: Ketamine (0.2 mg/ kg) bolus than the continuous supply of ketamine (0.05 mg/kg/h), group B: Magnesium sulphate (50mg/ kg) bolus and followed by continuous infusion of magnesium sulfate(10mg/kg /h). Result(s): the visual analogue scale was found to be significantly higher in group B compared to group A in 2, 4, and 8 hrs time intervals. The mean opioid (Morphine/Pethidine) consumption doses over 24h were lower in group A compared to group B. There is no significant difference regarding adverse events between the two studied groups. Conclusion: Intraoperative magnesium sulfate and ketamine infusionin patients exposed to gynecological surgeries with general anesthesia could and decreased the post-operative opioid requirement. Ketamine showed a significant preemptive analgesic effect compared to MgSO4 at 2 and 8 h postoperatively. VAS was significantly lowered in Ketamine than MgSO4.

Ketamine infusion reduces narcotic requirements following gastric bypass surgery: a randomized controlled trial.

As the obesity epidemic worsens, anesthesiologists should expect to see more obese patients presenting for surgical procedures. Opioids cause respiratory depression, which has caused complications in patients with obstructive sleep apnea. Opioids can also cause nausea, prolonging the time that patients spend in the postanesthesia care unit. Ketamine is a potential analgesic alternative that may have advantages to narcotics in the bariatric population. To determine whether an intraoperative ketamine infusion would reduce postoperative narcotic use in patients during the first 48 hours after laparoscopic gastric bypass. Major academic medical center. There were 54 participating patients. The intervention group (n = 27) was randomized to receive 100 μg of fentanyl with anesthesia induction, then a 20-mg bolus of ketamine, followed by a 5 μg/kg/min intraoperative ketamine infusion starting after anesthesia induction and ending after wound closure commenced. The control group (narcotic only, n = 27) also received 100 μg of fentanyl at anesthesia induction and intraoperative boluses of fentanyl at the discretion of the anesthesia team, with .3 mg of hydromorphone administered approximately 45 minutes before the completion of surgery. At 24 hours, the mean morphine-equivalent units (MEUs) were 12.7 (standard deviation [SD], 9.9; 95% confidence interval [CI], 8.8-16.6) for the ketamine group (n = 28) and 16.5 (SD, 9.8; 95% CI, 12.6-20.4) for the control group (n = 28). At 48 hours, the MEUs were 16.7 (SD, 12.0; 95% CI, 11.9-21.4) for the ketamine group and 22.7 (SD, 14.9; 95% CI, 16.8-28.6) for the control group. Cumulative MEUs for 24 hours (P = .039) and 48 hours (P = .058) postoperatively were lower in the ketamine group compared with the narcotic-only (control) group, although the difference at 48 hours did not reach statistical significance. Compared with the narcotic-only group, the ketamine group used 26% fewer MEUs after 24 hours and 31% fewer MEUs after 48 hours. This difference can mostly be attributed to group differences during the first 6 hours after surgery. Ketamine successfully reduced the amount of opioids required to control bariatric patients' pain at 24 hours postoperatively, but not over the 48-hour postoperative period.

The effect of erector spinae plane block on perioperative analgesic consumption and complications in dogs undergoing hemilaminectomy surgery: a retrospective cohort study

ObjectiveTo compare the perioperative use of analgesics and complication rates in dogs administered an erector spinae plane (ESP) block or a traditional opioid-based (OP) treatment as part of analgesic management during hemilaminectomy. Study designRetrospective cohort study. AnimalsMedical records of 114 client-owned dogs. MethodsGeneral data included demographics, duration of procedure, number of laminae fenestrated, perioperative use of steroid and non-steroidal anti-inflammatory drugs. Intra- and postoperative analgesics used in 48 hours and complications rates were compared between groups. Opioid use was expressed in morphine equivalents [ME (mg kg−1)]. Continuous data were compared using the Mann–Whitney U test and incidence of events with a Fisher's exact tests. Multiple linear regression was used to evaluate association between perioperative ME consumption (dependent variable) with other independent variables. Data are presented as median (range). Differences were considered significant when p < 0.05. ResultsGroup ESP comprised 42 dogs and group OP 72 dogs. No differences were observed in the general data. Intraoperative ME was 0.65 (0.20–3.74) and 0.79 (0.19–5.60) mg kg−1 in groups ESP and OP, respectively (p = 0.03). Intraoperative infusion of lidocaine was administered intravenously (IV) to 23.8% and 68% of groups ESP and OP, respectively (p < 0.0001). Intraoperative infusion of ketamine was administered IV to 21% and 40% of groups ESP and OP, respectively (p = 0.04). Regression analysis revealed the ESP block as the only independent variable affecting the perioperative ME consumption. Pharmacological intervention to treat cardiovascular complications was administered to 21.4% and 47.2% of dogs in groups ESP and OP, respectively (p = 0.008). There were no differences in postoperative complication rates. Conclusions and clinical relevanceESP block was associated with reduced perioperative opioid consumption, intraoperative adjuvant analgesic use and incidence of pharmacological interventions to treat cardiovascular complications in dogs undergoing hemilaminectomy.

Comparative study of retrobulbar block versus ketamine infusion during eye enucleation/evisceration (randomized controlled trial)

Background:The aim of this study is to compare the safety and efficacy of retrobulbar block versus intraoperative ketamine infusion in eye enucleation or evisceration under general anesthesia.Materials and Methods:Forty-five patients belonging to American Society of Anesthesiologists Physical Status I and II undergoing eye enucleation or evisceration were randomly allocated to three equal groups (15 patients each). General anesthesia was used as the standardized technique in all patients. Group R received a single retrobulbar injection, Group K received intravenous ketamine infusion, and Group C received normal saline with the same rate of ketamine infusion. Intraoperative heart rate and mean arterial pressure, recovery time, postoperative pain score, time to first rescue analgesic, number of patients who required rescue analgesia, and any adverse events were reported.Results:Postoperative pain Visual Analog Scale was significantly lower in R and K groups in comparison to the C group and was significantly higher in K than R group at 3, 6, 12, and 24 h. In addition, the time to first rescue analgesic was significantly longer in R group (429 ± 54 min) than that in K group (272 ± 34 min), but compared to both groups, it was longer in C group (52 ± 7 min). In K group, the recovery time was longer with higher sedation score in comparison to the other two groups.Conclusions:Single retrobulbar injection and low-dose ketamine infusion are safe and effective when used as adjuvants to general anesthesia, but retrobulbar block provides better control of postoperative pain with prolonged time to first rescue analgesic and reduced analgesic consumption.

Intraoperative Ketamine in Total Knee Arthroplasty Does Not Decrease Pain and Narcotic Consumption: A Prospective Randomized Controlled Trial

BackgroundMultiple studies have demonstrated that ketamine, a glutamate receptor blocker, may decrease postoperative pain in abdominal and orthopedic surgeries. However, its role with spinal anesthesia and total knee arthroplasty (TKA) remains unknown. The purpose of this study is to determine the efficacy of subanesthetic dosing of ketamine during TKA on postoperative pain and narcotic consumption. MethodsIn this prospective, randomized, double-blinded clinical trial, we enrolled 91 patients undergoing primary TKA with spinal anesthesia in a single institution from 2017 to 2018. Patients were randomized to receive intraoperative ketamine infusion at a rate of 6 mcg/kg/min for 75 minutes or a saline placebo. All patients received spinal anesthesia and otherwise identical surgical approaches, pain management, and rehabilitation protocols. Patient-reported visual analog pain scores were calculated preoperatively, postoperative days (POD) 0-7, and 2 weeks. Narcotic consumption was evaluated on POD 0 and 1. ResultsThere was no difference in average pain between ketamine and placebo at all time points except for at PODs 1 (45 vs 56, P = .041) and 4 (39 vs 49, P = .040). For least pain experienced, patients administered with ketamine experienced a reduction in pain only at POD 4 (22 vs 35, P = .011). There was no difference in maximum pain cohorts at all time points of the study or in-hospital morphine equivalents between the 2 cohorts. ConclusionAs part of multimodal pain management protocol, intraoperative ketamine does not result in a clinically significant improvement in pain and narcotic consumption following TKA.

Effects of low-dose ketamine infusion on remifentanil-induced acute opioid tolerance and the inflammatory response in patients undergoing orthognathic surgery.

PurposeRemifentanil is associated with acute opioid tolerance that can lead to increased postoperative consumption of opioid analgesics. The purpose of this study was to determine whether a low dose of ketamine prevents remifentanil-induced acute opioid tolerance and affects the neutrophil–lymphocyte ratio (NLR), a newly recognized biomarker of inflammation.Materials and methodsForty patients undergoing orthognathic surgery were enrolled in this prospective, randomized, double-blind study and randomly assigned to intraoperative administration of one of the following anesthetic regimens: high-dose remifentanil (0.6 µg/kg/minute); low-dose remifentanil (0.2 µg/kg/minute); or high-dose remifentanil with ketamine (remifentanil 0.6 µg/kg/minute with 0.5 mg/kg ketamine just after induction followed by an intraoperative infusion of ketamine 5 µg/kg/minute until wound closure). Fentanyl by intravenous patient-controlled analgesia was used for postoperative pain control. Visual Analog Scale pain scores and fentanyl consumption were recorded in the first 24 hours postoperatively. Perioperative serum C-reactive protein level and NLR were also determined.ResultsBaseline characteristics were similar in the three study groups. There were no between-group differences in Visual Analog Scale pain scores during the study period. The high-dose remifentanil group had a significantly higher requirement for fentanyl than the other two groups. Addition of ketamine did not affect the C-reactive protein level but increased the NLR; this increase was associated with decreased fentanyl consumption.ConclusionHigh-dose intraoperative remifentanil induced postoperative acute opioid tolerance that was prevented by infusion of low-dose ketamine. Ketamine increased the postoperative NLR associated with decreased fentanyl requirement for postoperative pain control.

Low-dose ketamine infusion reduces postoperative hydromorphone requirements in opioid-tolerant patients following spinal fusion: A randomised controlled trial.

The current opioid epidemic highlights the urgent need for effective adjuvant therapies to complement postoperative opioid analgesia. Intra-operative ketamine infusion has been shown to reduce postoperative opioid consumption and improve pain control in opioid-tolerant patients after spinal fusion surgery. Its efficacy for opioid-naïve patients, however, remains controversial. We hypothesised that low-dose ketamine infusion after major spinal surgery reduces opioid requirements in opioid-tolerant patients, but not in opioid-naïve patients. Randomised placebo-controlled study. Single-centre, tertiary care hospital, November 2012 until November 2014. A total of 129 patients were classified as either opioid-tolerant (daily use of opioid medications during 2 weeks preceding the surgery) or opioid-naïve group, then randomised to receive either ketamine or placebo; there were thus four groups of patients. All patients received intravenous hydromorphone patient-controlled analgesia postoperatively. Patients in the ketamine groups received a ketamine infusion (bolus 0.2 mg kg over 30 min followed by 0.12 mg kg h for 24 h). Patients in the placebo groups received 0.9% saline. The primary outcome was opioid consumption during the first 24 h postoperatively. The secondary outcome was numerical pain scores during the first 24 h and central nervous system side effects. Postoperative hydromorphone consumption was significantly reduced in the opioid-tolerant ketamine group, compared with the opioid-tolerant placebo group [0.007 (95% CI 0.006 to 0.008) versus 0.011 (95% CI 0.010 to 0.011) mg kg h, Bonferroni corrected P < 0.001]. There was no difference in hydromorphone use between the opioid-naïve groups (0.004 and 0.005 mg kg h in the opioid-naïve ketamine and placebo group, respectively, P = 0.118). Pain scores did not differ significantly between the opioid-tolerant ketamine group and the opioid-naïve groups. There was no significant difference in side effects among groups. Postoperative low-dose ketamine infusion reduces opioid requirements for the first 24 h following spinal fusion surgery in opioid-tolerant, but not in opioid-naïve patients. NCT03274453 with clinicaltrials.gov.

Prospective, randomized, and controlled trial on ketamine infusion during bilateral axillo-breast approach (BABA) robotic or endoscopic thyroidectomy: Effects on postoperative pain and recovery profiles: A consort compliant article.

Background:Robotic or endoscopic thyroidectomy using bilateral axillo-breast approach (BABA) is frequently performed for excellent cosmesis. However, postoperative pain is remained as concerns due to the extent tissue dissection and tension during the operation. Ketamine is a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist that reduces acute postoperative pain. We evaluated the effects of intraoperative ketamine infusion on postoperative pain control and recovery profiles following BABA robotic or endoscopic thyroidectomy.Methods:Fifty-eight adult patients scheduled for BABA robotic or endoscopic thyroidectomy were randomized into a control group (n = 29) and ketamine group (n = 29). Following induction of anesthesia, patients in each group were infused with the same volume of saline or ketamine solution (1 mg/kg bolus, 60 μg/kg/h continuous infusion). Total intravenous anesthesia with propofol and remifentanil was used to induce and maintain anesthesia. Pain scores (101-point numerical rating scale, 0 = no pain, 100 = the worst imaginable pain), the consumption of rescue analgesics, and other postoperative adverse effects were assessed at 1, 6, 24, and 48 hours postoperatively.Results:Patients in the ketamine group reported lower pain scores than those in the control group at 6 hours (30 [30] vs 50 [30]; P = 0.017), 24 hours (20 [10] vs 30 [20]; P < 0.001), and 48 hours (10 [10] vs 20 [15]; P < 0.001) in neck area. No statistically significant differences were found between the 2 groups in terms of the requirements for rescue analgesics or the occurrence of adverse events.Conclusion:Intravenous ketamine infusion during anesthesia resulted in lower postoperative pain scores following BABA robotic or endoscopic thyroidectomy, with no increase in adverse events.

Abstract PR347

Background & Objectives: Postoperative pain management is challenging. There is still room for improvement despite established acute pain protocols. We compared the efficacy between two low doses of intraoperative ketamine infusions in reducing the first 24 hours postoperative morphine consumption. Materials & Methods: Fifty patients with American Society of Anesthesiologists’ (ASA) Physical Status I or II aged between 18 to 65 years undergoing open gynaecological surgeries were randomised into three groups to receive intraoperative infusions of normal saline (Group A), ketamine at 0.25 mg/kg/hour (Group B) or ketamine at 0.5 mg/kg/hour (Group C). All patients received intraoperative intravenous morphine 0.1 mg/kg. Postoperative morphine consumption via patient controlled analgesia device, visual analogue scale (VAS) for pain and ketamine side effects were recorded at times zero, 10, 20, 30 minutes, and 6, 12, 24 hours postoperatively. Results: Mean cumulative 24 hours postoperative morphine consumption was significantly reduced in Groups B and C (23.1 ± 8.4 mg and 16.7 ± 7.2 mg respectively) when compared to Group A (30.9 ± 11.1 mg). Group C had significantly lower VAS pain scores and rescue morphine requirements in the postoperative period. There were no significant adverse side effects in all 3 groups. Conclusion: Intraoperative ketamine infusion at 0.5 mg/kg/hour significantly improved pain control and reduced postoperative morphine consumption.