Intra- and postoperative low-dose ketamine for adolescent idiopathic scoliosis surgery: a randomized controlled trial

Effect of Low-dose Ketamine Infusion on Opioid Consumption in Children Undergoing Open Cardiac Surgery: A Randomized Controlled Double-Blind Study

OBJECTIVE

This study was designed to evaluate the effect of low-dose ketamine infusion on the perioperative consumption of opioids in pediatric open cardiac surgery.

DESIGN

A randomized, controlled, double-blinded single-center study was conducted.

SETTING

The study took place in a tertiary care children's hospital.

PARTICIPANTS

Patients of both sexes aged 2-12 years who underwent cardiac surgery were included.

INTERVENTIONS

Patients in the ketamine group received a bolus of 0.3 mg/kg of ketamine before skin incision followed by continuous intraoperative infusion of 0.25 mg/kg/h and postoperative infusion of 0.1 mg/kg/h for 24 h. Patients in the control groups received volumes of normal saline either bolus or continuous infusion like that of the ketamine group.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the total dose of fentanyl consumed over the first 24 hours postoperatively. Secondary outcomes were intraoperative fentanyl consumption, time to extubation, modified objective pain score, and incidence of vomiting, pruritus, diplopia, or hallucinations. A total of 80 patients were recruited but the final analysis was done on 35 patients in the ketamine group and 34 in the control group. Fentanyl consumption during surgery and in the first 24 hours postoperatively was significantly lower in the ketamine than the control group. Patients in both the ketamine and control groups had similar times to extubation. Modified objective pain scores were significantly lower in the ketamine group than the control group. None of the patients in either group had diplopia or hallucinations.

CONCLUSIONS

Low-dose ketamine infusion in children undergoing open cardiac surgery reduced intra- and postoperative opioid consumption and postoperative pain scores. Moreover, ketamine did not cause diplopia or hallucinations.

PCA-pump for analgesia following pediatric scoliosis surgery: bolus administration with/without basal infusion

OBJECTIVES

The aim of this study is to compare the use of two different opioid delivery systems (bolus PCA with/without basal infusion) to control postoperative pain and evaluate the side effect profile in pediatric patients undergoing scoliosis surgery.

PATIENTS AND METHODS

38 patients who underwent posterior spinal fusion for adolescent idiopathic scoliosis were included in the study. Patients were randomly divided into 2 groups by the computer. Patients who received only bolus PCA were named Group 1, and patients who received bolus PCA with basal infusion were named Group 2.Morphine consumption, postoperative pain assessmentduring rest, movement and coughing with numeric rating scale (NRS) and the Wong -Baker pain scale, heart rate and average blood pressure, sedation levels withRamsey sedation scale and side effects such as nausea, vomiting, itching, desaturation, and urinary retention were recorded.

RESULTS

Total mean morphine consumption (mg) was 32.7 ± 9.7 in Group 1 and 43.4 ± 9.1 in Group 2. The mean morphine consumption (mg) at 12-24 hours and 0-48 hours in Group 1 was statistically lower than Group 2 (p = 0.001). There was no significant difference between the groups in terms of median NRS scores (p = 0.55). There was no statistically significant difference in the evaluation of the groups in terms of Wong-Baker pain scale. Wong-Baker pain scale is p:0.66 at the 2nd hour, p:0.951 at the 12th hour and p:0.467 at the 24th hour.There was no statistically significant difference in Ramsay Sedation Scale evaluation between groups during each follow-up time (p > 0.05). The Ramsay Sedation Scale was p: 0.94 at the 2nd hour, p:1.0 at the 12th hour, and p:1.0 at the 24th hour. The duration of vomiting between 0-2 h, 2-24 h and 0-48 h was higher in Group 2 (p = 0.001, p = 0.024, p = 0.001).

CONCLUSION

The two administration settings of morphine sulphate by PCA pump have shown to be equally effective in the treatment of postoperative pain following PSF. In addition, PCA with basal infusion administration causes more opioid consumption and more systemic side effects. Therefore, the use of only bolus PCA in pediatric scoliosis surgery should be encouraged.

LEVEL OF EVIDENCE

Level II, Randomized Controlled Trial.

The impact of ketamine on outcomes in critically ill patients: a systematic review with meta-analysis and trial sequential analysis of randomized controlled trials

BACKGROUND

This meta-analysis aims to evaluate the effects of ketamine in critically ill intensive care unit (ICU) patients.

METHODS

We searched for randomized controlled trials (RCTs) in PubMed, Scopus, and the Cochrane Library; the search was performed initially in January but was repeated in December of 2023. We focused on ICU patients of any age. We included studies that compared ketamine with other traditional agents used in the ICU. We synthesized evidence using RevMan v5.4 and presented the results as forest plots. We also used trial sequential analysis (TSA) software v. 0.9.5.10 Beta and presented results as TSA plots. For synthesizing results, we used a random-effects model and reported differences in outcomes of two groups in terms of mean difference (MD), standardized MD, and risk ratio with 95% confidence interval. We assessed the risk of bias using the Cochrane RoB tool for RCTs. Our outcomes were mortality, pain, opioid and midazolam requirements, delirium rates, and ICU length of stay.

RESULTS

Twelve RCTs involving 805 ICU patients (ketamine group, n=398; control group, n=407) were included in the meta-analysis. The ketamine group was not superior to the control group in terms of mortality (in five studies with 318 patients), pain (two studies with 129 patients), mean and cumulative opioid consumption (six studies with 494 patients), midazolam consumption (six studies with 304 patients), and ICU length of stay (three studies with 270 patients). However, the model favored the ketamine group over the control group in delirium rate (four studies with 358 patients). This result is significant in terms of conventional boundaries (alpha=5%) but is not robust in sequential analysis. The applicability of the findings is limited by the small number of patients pooled for each outcome.

CONCLUSIONS

Our meta-analysis did not demonstrate differences between ketamine and control groups regarding any outcome except delirium rate, where the model favored the ketamine group over the control group. However, this result is not robust as sensitivity analysis and trial sequential analysis suggest that more RCTs should be conducted in the future.

Nausea and Vomiting After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: A Systematic and Critical Analysis Review

BACKGROUND

Postoperative nausea and vomiting (PONV) affects patient satisfaction, health care costs, and hospital stay by complicating the postoperative recovery period after adolescent idiopathic scoliosis (AIS) spinal fusion surgery. Our goal was to identify recommendations for optimal management of PONV in AIS patients undergoing posterior spinal fusion (PSF).

METHODS

We performed a systematic review in June 2022, searching the PubMed and Embase electronic databases using search terms "(Adolescent idiopathic scoliosis) AND (Postoperative) AND (Nausea) AND (Vomiting)." Three authors reviewed the 402 abstracts identified from January 1991 to June 2022. Studies that included adolescents or young adults (<21 years) with AIS undergoing PSF were selected for full-text review by consensus. We identified 34 studies reporting on incidence of PONV. Only 6 studies examined PONV as the primary outcome, whereas remaining were reported PONV as a secondary outcome. Journal of Bone and Joint Surgery Grades of recommendation were assigned to potential interventions or clinical practice influencing incidence of PONV with respect to operative period (preoperative, intraoperative, and postoperative period) on the basis that potential guidelines/interventions for PONV can be targeted at those periods.

RESULTS

A total of 11 factors were graded, 5 of which were related to intervention and 6 were clinical practice-related. Eight factors could be classified into the operative period-1 in the intraoperative period and 7 in the postoperative period, whereas the remaining 3 recommendations had overlapping periods. The majority of grades of recommendations given were inconclusive or conflicting. The statement that neuraxial and postoperative systemic-only opioid therapy have a similar incidence of PONV was supported by good (Grade A) evidence. There was fair (Grade B) and poor evidence (Grade C) to avoid opioid antagonists and nonopioid local analgesia using wound catheters as PONV-reducing measures.

CONCLUSION

Although outcomes after spinal fusion for AIS have been studied extensively, the literature on PONV outcomes is scarce and incomplete. PONV is most commonly included as a secondary outcome in studies related to pain management. This study is the first to specifically identify evidence and recommendations for interventions or clinical practice that influence PONV in AIS patients undergoing PSF. Most interventions and clinical practices have conflicting or limited data to support them, whereas others have low-level evidence as to whether the intervention/clinical practice influences the incidence of PONV. We have identified the need for expanded research using PONV as a primary outcome in patients with AIS undergoing spinal fusion surgery.

Error traps and preventative strategies for adolescent idiopathic scoliosis spinal surgery

Anesthesia for posterior spinal fusion for adolescent idiopathic scoliosis remains one of the most common surgeries performed in adolescents. These procedures have the potential for significant intraprocedural and postoperative complications. The potential for pressure injuries related to prone positioning must be understood and addressed. Additionally, neuromonitoring remains a mainstay for patient care in order to adequately assess patient neurologic integrity and alert the providers to a reversible action. As such, causes of neuromonitoring signal loss must be well understood, and the provider should have a systematic approach to signal loss. Further, anesthetic design must facilitate intraoperative wake-up to allow for a definitive assessment of neurologic function. Perioperative bleeding risk is high in posterior spinal fusion due to the extensive surgical exposure and potentially lengthy operative time, so the provider should undertake strategies to reduce blood loss and avoid coagulopathy. Pain management for adolescents undergoing spinal fusion is also challenging, and inadequate analgesia can delay recovery, impede patient/family satisfaction, increase the risk of chronic postsurgical pain/disability, and lead to prolonged opioid use. Many of the significant complications associated with this procedure, however, can be avoided with intentional and evidence-based approaches covered in this review.

Ketamine for postoperative pain treatment in spinal surgery: Systematic review with meta-analysis and trial sequential analysis

AIM

We aimed to assess the beneficial and harmful effects of perioperative pain treatment with ketamine in patients undergoing spinal surgery.

METHODS

We searched Medline, Embase, and CENTRAL from inception until 15 February 2023 for randomised clinical trials comparing ketamine with placebo or no intervention in patients undergoing spinal surgery. The primary outcomes were cumulative opioid consumption at 24 h postoperatively and serious adverse events. We adhered to recommendations of the Cochrane Collaboration and performed meta-analysis, Trial Sequential Analysis (TSA) to assess the risks of random errors, risk of bias assessment to evaluate the risks of systematic errors, and used the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

We included a total of 28 randomised clinical trials enrolling 2110 participants providing data for our pre-defined outcomes. Twenty-three trials enrolled adult participants and 5 trials enrolled paediatric participants. Three trials were at low risk of bias. Meta-analysis and TSA of trials including adults showed that ketamine versus placebo or no intervention seemed to reduce the cumulative 24-h opioid consumption (mean difference -17.57 mg; TSA-adjusted 95% confidence interval, -24.22 to -10.92; p < .01; low certainty of evidence), and there was no evidence of a difference of ketamine versus placebo or no intervention on the risk of serious adverse events (risk ratio 2.16; 96.7% confidence interval, 0.35 to 13.17; p = .36; very low certainty of evidence).

CONCLUSION

In adults undergoing spinal surgery, ketamine may reduce cumulative 24-h opioid consumption. Ketamine may increase the occurrence of serious adverse events, but the evidence was very uncertain.

Is PONV still a problem in pediatric surgery: a prospective study of what children tell us

Background

Postoperative nausea and vomiting (PONV) is an unpleasant complication after surgery that commonly co-occurs with pain. Considering the high prevalence among pediatric patients, it is important to explore the main risk factors leading to PONV in order to optimize treatment strategies. The objectives of this study are as follows: (1) to determine the prevalence of PONV on the day of surgery by conducting interviews with pediatric patients, (2) to assess PONV prevalence in the recovery room and on the ward by analyzing nursing records, and (3) to collect information on PONV risk factors on the day of surgery and the following postoperative days. We wanted to investigate real-life scenarios rather than relying on artificially designed studies.

Methods

A prospective analysis [according to STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines] of PONV on the day of surgery and the following postoperative days was conducted by evaluating demographic and procedural parameters, as well as conducting interviews with the children under study. A total of 626 children and adolescents, ranging in age from 4 to 18 years, were interviewed on the ward following their surgery. The interviews were conducted using a questionnaire, as children aged 4 and above can participate in an outcome-based survey.

Results

On the day of surgery, several multivariable independent predictors were identified for PONV. The type of surgery was found to be a significant factor (p = 0.040) with the highest odds ratio (OR) in patients with procedural investigations [OR 5.9, 95% confidence interval (CI): 1.8-19.2], followed by abdominal surgery (OR 3.1, 95% CI: 0.9-11.1) when inguinal surgery was used as the reference category. In addition, the study identified several predictors, including the amount of fentanyl administered during anesthesia (µg/kg body weight) (OR 1.4, 95% CI: 1.1-1.8), intraoperative use of piritramide (OR 2.6, 95% CI: 1.5-4.4) and diclofenac (OR 2.0, 95% CI: 1. 3-3.1), opioid administration in the recovery room (OR 3.0, 95% CI: 1.9-4.7), and piritramide use on the ward (OR 4.5, 95% CI: 1.7-11.6).

Conclusions

The main risk factors for PONV include the intraoperative administration of opioids during the recovery room stay and at the ward, the intraoperative use of non-opioids (diclofenac), and the specific type of surgical procedure. Real-life data demonstrated that in clinical praxis, there is a gap between the adherence to established guidelines and the use of antiemetic prophylaxis in surgeries that are generally not associated with a high PONV prevalence. Further efforts are needed to improve the existing procedures and thus improve the overall outcome.

Meta-analysis of the efficacy of ketamine in postoperative pain control in adolescent idiopathic scoliosis patients undergoing spinal fusion

PURPOSE

In this meta-analysis, we aim to compare ketamine use versus a control group (saline solution) during induction of anesthesia in adolescent idiopathic scoliosis patients undergoing fusion surgery in terms of postoperative opioid consumption, pain control, and side effects.

METHODS

A PubMed search of studies published over the last 20 years using the descriptor/terms "ketamine AND scoliosis" was performed. Baseline characteristics of each article were obtained and efficacy measures analyzed (morphine equivalent treatment at 24, 48, and 72 h postoperatively, complications (vomiting/nausea and pruritus), length of hospital stay (days); and pain score (VAS)) (Review Manager 5.4 software package).

RESULTS

Five randomized clinical trials were included. Morphine administration showed statistically significant differences at 24 and 48 h (MD - 0.15, 95% CI - 0.18 to - 0.12) and (MD - 0.26, 95% CI - 0.31 to - 0.21) between the ketamine and control (saline solution), respectively. No intergroup differences were found regarding nausea/vomiting and pruritus (OR 0.77, 95% CI 0.35 to 1.67) and (OR 0.71, 95% CI 0.31 to 1.62), respectively, same as for the pain score (MD - 0.75, 95% CI - 1.71 to 0.20).

CONCLUSIONS

The use intraoperative and postoperative continuous low doses of ketamine significantly reduces opioid use throughout the first 48 h in patients with AIS who undergo posterior spinal fusion.

Low-dose ketamine infusions reduce opioid use in pediatric and young adult oncology patients

BACKGROUND

Ketamine is an NMDA-receptor antagonist with analgesic and opioid-sparing properties. Although well studied in adults, more robust evidence supporting ketamine's use for pediatric pain management is needed. This retrospective study evaluates ketamine's opioid-sparing effectiveness in pediatric and young adult oncology and hematology patients.

PROCEDURE

Continuous ketamine infusions administered for pain management between 2010-2020 were reviewed. Data including demographic characteristics, oncology/hematology and pain diagnoses, concurrent pain medications, and ketamine infusions' dose and duration were collected. Opioid consumption data based on delivery via patient-controlled analgesia were collected 1 day before (D1), all days during (cumulatively named D2), and 1 day after (D3) ketamine infusions and calculated as morphine-equivalent doses (mg/kg/day). Data were reported for the entire study group as well as for distinct oncology and end-of-life categories, and short-term acute pain circumstances which included vaso-occlusive crises in hematology patients. Side effects were reviewed.

RESULTS

Significantly lower daily opioid consumption was noted in the oncology group, while decreases were not significant in the end-of-life group and in the overall study population. The acute pain group did not show an opioid reduction associated with the ketamine infusions. A largely tolerable side-effect profile was observed, with no differences among each group's incidence.

CONCLUSIONS

Ketamine infusions were associated with significantly reduced opioid consumption for oncology patients. The opioid-sparing effects of ketamine may vary according to clinical diagnoses and circumstances of use. Overall, low-dose ketamine infusions present an acceptable safety profile in pediatric and young adult patients; nevertheless, individual risks and benefits should be considered.

Clinical Uses of Ketamine in Children: A Narrative Review

Ketamine is a phencyclidine derivative that acts as a noncompetitive N-methyl-D-aspartate as well as a glutamate receptor antagonist. It also has other minor mechanisms that contribute to its extensive drug profile. Ketamine is a bronchodilator and maintains normal airway reflexes and, thus, permits spontaneous respiration. This, coupled with the fact that it produces potent analgesia, makes it highly suitable for children.

Despite its many merits, the drug’s side effects, along with its cultural image of being a drug of abuse, a drug used in veterinary medicine, or a “date-rape drug” have sullied its reputation within the armamentarium of medicine. Even though it is widely used in developing countries, its use in Western nations has diminished. We have strived to explore the various clinical uses of ketamine in children through this article. In addition, the article also highlights how some of the fears associated with using the drug are unfounded and provides ways by which the drug’s side effects can be prevented and managed.

Statistical Fragility of Ketamine Infusion during Scoliosis Surgery to Reduce Opioid Tolerance and Postoperative Pain

OBJECTIVE

Randomized controlled trials (RCTs) have come under scrutiny due to a frequent lack of reproducibility, due in part to shortcomings of the common p<0.05 threshold for significance. Here, we utilize fragility indices to assess the statistical robustness of RCTs evaluating low-dose ketamine during scoliosis surgery to reduce opioid tolerance and postoperative pain.

METHODS

RCTs evaluating outcomes after intraoperative ketamine infusion in adolescent idiopathic scoliosis (AIS) patients were included. Relevant outcomes included pain, opioid consumption, quality of life, anesthesia, sedation, adverse effects, and length of stay. The dichotomous or continuous fragility index (FI or CFI) was determined by manipulating each outcome event until reversal of significance (a=0.05) was achieved. The corresponding fragility quotients (FQ) were calculated by dividing the FI or CFI by the sample size.

RESULTS

Of 27 studies screened, 6 studies (61 outcome events) were included. The median FI for dichotomous events was 2.0 (FQ=0.045), suggesting that altering the outcome of only 2 patients (or 4.5 out of 100) would reverse trial significance. For continuous events, altering the treatment of only 6 patients (or 14.1 out of 100) would reverse significance. Outcome events that were originally reported as significant (p<0.05) were considerably more fragile (FI=1.5; CFI=3.5) than events that were reported as nonsignificant (FI=2.0; CFI=7.0).

CONCLUSIONS

While evidence for ketamine use is promising, our fragility analysis suggests that RCT findings may be underpowered in some cases. Given the importance of RCTs in clinical decision-making, fragility indices should be reported alongside p-values to indicate the strength of statistical findings.

Perioperative Low-Dose Ketamine for Postoperative Pain Management in Spine Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective

Although low-dose ketamine has been shown to be generally beneficial in terms of pain control in a variety of major surgery, there is no consensus regarding the effectiveness of supplemental ketamine analgesic use exclusively in spine surgery. The objective of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to assess the efficacy and safety of perioperative low-dose ketamine for pain management and analgesic consumption in patients undergoing spine surgery.

Methods

A comprehensive literature search was performed for relevant studies using PubMed, EMBASE, Web of Science, and Cochrane Library. Patients who received perioperative low-dose ketamine were compared to the control group in terms of postoperative pain intensity, opioid consumption, and adverse events. Patients were further categorized by ages and administration times for subgroup analysis.

Results

A total of 30 RCTs comprising 1,865 patients undergoing elective spine surgery were included. Significantly lower pain intensity and less opioid consumption at 12 h, 24 h, and 48 h postoperatively and lower incidence of postoperative nausea and vomiting (PONV) were observed in the ketamine group (all P < 0.05). There was no significant difference of central nervous system (CNS) adverse events between groups. However, different efficacy of low-dose ketamine was detected when patients were categorized by ages and administration times.

Conclusion

Perioperative low-dose ketamine demonstrated analgesic and morphine-sparing effect with no increased adverse events after spine surgery. However, this effect was not significant in pediatric patients. Only postoperative or intraoperative and postoperative administration could prolong the analgesic time up to 48 h postoperatively. Further studies should focus on the optimal protocol of ketamine administration and its effect on old age participants.

Impact of Ketamine on Analgosedative Consumption in Critically Ill Patients: A Systematic Review and Meta-Analysis

Objective:

The aim of this study was to synthesize evidence available on continuous infusion ketamine versus nonketamine regimens for analgosedation in critically ill patients.

Data sources

A search of MEDLINE, EMBASE, CINAHL, CDSR, and ClinicalTrials.gov was performed from database establishment to November 2021 using the following search terms: critical care, ICU, ketamine, sedation, and anesthesia. All studies included the primary outcome of interest: daily opioid and/or sedative consumption.

Study selection and data extraction

Relevant human studies were considered. Randomized controlled trials (RCT), quasi-experimental studies, and observational cohort studies were eligible. Two reviewers independently screened articles, extracted data, and appraised studies using the Cochrane RoB and ROBINS-I tools.

Data synthesis

A total of 13 RCTs, 5 retrospective, and 1 prospective cohort study were included (2255 participants). The primary analysis of six RCTs demonstrated reduced opioid consumption with ketamine regimens (n = 494 participants, −13.19 µg kg⁻¹ h⁻¹ morphine equivalents, 95% CI −22.10 to −4.28, P = 0.004). No significant difference was observed in sedative consumption, duration of mechanical ventilation (MV), ICU or hospital length of stay (LOS), intracranial pressure, and mortality. Small sample size of studies may have limited ability to detect true differences between groups.

Relevance to patient care and clinical practice

This meta-analysis examining ketamine use in critically ill patients is the first restricting analysis to RCTs and includes up-to-date publication of trials. Findings may guide clinicians in consideration and dosing of ketamine for multimodal analgosedation.

Conclusion

Results suggest ketamine as an adjunct analgosedative has the potential to reduce opioid exposure in postoperative and MV patients in the ICU. More RCTs are required before recommending routine use of ketamine in select populations.

A systematic review of therapeutic ketamine use in children and adolescents with treatment-resistant mood disorders

Suicide is the second leading cause of death in the United States among individuals aged 10-24, and severe youth depression is often refractory to the current standards of care. Many studies have demonstrated the efficacy of ketamine in reducing depressive symptoms in adults with treatment-resistant mood disorders, though few studies utilizing ketamine in youth populations exist. This systematic review examines the current state of evidence for ketamine use in children with treatment-resistant mood disorders. We conducted a search utilizing two electronic databases for English-language studies investigating the therapeutic effects and side effect profile of ketamine in youth ≤ 19 years of age with a diagnosis of a treatment-resistant mood disorder. Analysis included subjects with treatment-resistant depression with and without psychotic features and with bipolar disorder. Primary outcome measures included the following scales: Montgomery-Asberg Depression Rating Scale, Children's Depression Rating Scale, Children's Depression Rating Scale Revised, Child Bipolar Questionnaire, Overt Aggression Scale, Yale-Brown Obsessive-Compulsive Scale, and Scale for Suicidal Ideation. Four published studies were identified that investigated therapeutic ketamine use in youth for the primary purpose of treating a treatment-resistant psychiatric disorder. Three additional studies that did not meet eligibility criteria were identified and discussed. Ketamine was shown in youth to generally improve depressive symptoms, decrease acute suicidality, and reduce mood lability, though a number of subjects remained resistant to its treatment. These findings substantiate the need for further longitudinal studies investigating ketamine's long-term safety, its efficacy, and abuse potential in the youth.

A Bolus Dose of Ketamine Reduces the Amplitude of the Transcranial Electrical Motor-evoked Potential: A Randomized, Double-blinded, Placebo-controlled Study

BACKGROUND

A low-dose bolus or infusion of ketamine does not affect transcranial electrical motor-evoked potential (MEP) amplitude, but a dose ≥1 mg/kg may reduce MEP amplitude. We conducted a randomized, double-blinded, placebo-controlled study to evaluate the effect of ketamine (1 mg/kg) on transcranial electrical MEP.

METHODS

Twenty female patients (aged 12 to 18 y) with adolescent idiopathic scoliosis scheduled to undergo posterior spinal fusion were randomly allocated to receive ketamine or saline. General anesthesia was induced and maintained with continuous infusions of propofol and remifentanil. MEP was elicited by supramaximal transcranial electrical stimulation. MEP recordings were obtained at baseline and then at 2, 4, 6, 8, and 10 minutes after administration of ketamine (1 mg/kg) or saline (0.1 ml/kg). The primary endpoint was the minimum relative MEP amplitude (peak-to-peak amplitude, % of baseline value) recorded from the left tibialis anterior muscle. The baseline amplitude recorded before test drug administration was defined as 100%.

RESULTS

Medians (interquartile range) minimum MEP amplitudes in the left tibialis anterior muscle in the ketamine and saline groups were 26% (9% to 34%) and 87% (55% to 103%) of the baseline value, respectively (P<0.001). MEP amplitudes in other muscles were significantly reduced by ketamine. The suppressive effect of ketamine lasted for at least 10 minutes in each muscle.

CONCLUSION

A 1-mg/kg bolus dose of ketamine can reduce MEP amplitude. Anesthesiologists should consider the dosage and timing of intravenous ketamine administration during MEP monitoring.

Postoperative Nausea and Vomiting in Pediatric Patients

Postoperative nausea and vomiting (PONV), postoperative vomiting (POV), post-discharge nausea and vomiting (PDNV), and opioid-induced nausea and vomiting (OINV) continue to be causes of pediatric morbidity, delay in discharge, and unplanned hospital admission. Research on the pathophysiology, risk assessment, and therapy for PDNV, OINV and pain therapy options in children has received increased attention. Multimodal pain management with the use of perioperative regional and opioid-sparing analgesia has helped decrease nausea and vomiting. Two common emetogenic surgical procedures in children are adenotonsillectomy and strabismus repair. Although PONV risk factors differ between adults and children, the approach to decrease baseline risk is similar. As PONV and POV are frequent in children, antiemetic prophylaxis should be considered for those at risk. A multimodal approach for antiemetic and pain therapy involves preoperative risk evaluation and stratification, antiemetic prophylaxis, and pain management with opioid-sparing medications and regional anesthesia. Useful antiemetics include dexamethasone and serotonin 5-hydroxytryptamine-3 (5-HT3) receptor antagonists such as ondansetron. Multimodal combination prophylactic therapy using two or three antiemetics from different drug classes and propofol total intravenous anesthesia should be considered for children at high PONV risk. "Enhanced recovery after surgery" protocols include a multimodal approach with preoperative preparation, adequate intravenous fluid hydration, opioid-sparing analgesia, and prophylactic antiemetics. PONV guidelines and management algorithms help provide effective postoperative care for pediatric patients.

Low-Dose Ketamine Infusion Versus Morphine Infusion During Abdominoplasty to Change the Postoperative Pain Profile

BACKGROUND

With the increased number of abdominoplasty all over the world, and the need to manage postoperative pain, it is a must to find proper and effective drugs to decrease opioid consumption in the postoperative period.

OBJECTIVES

In this double-blind randomized controlled clinical trial, we assumed that low-dose ketamine infusion will reduce the postoperative pain profile than the conventional method of morphine.

METHODS

The scheduled patients for abdominoplasty under general anesthesia were recruited in two groups: group (K) with low-dose ketamine infusion intra-operatively (80 patients) and group (M) with morphine infusion intra-operatively (80 patients). Both groups were monitored intraoperatively and postoperatively for rescue doses of fentanyl, visual analogue scale (VAS), and side effects.

RESULTS

There were no statistical differences between both groups regarding the fentanyl rescue doses intra- and postoperative with no remarkable side effects.

CONCLUSIONS

Low-dose ketamine has a useful analgesic effect in abdominoplasty similar to morphine without remarkable side effects, such as sedation or hallucinations.

Postoperative Pain Management in Pediatric Spinal Fusion Surgery for Idiopathic Scoliosis

This article reviews and summarizes current evidence and knowledge gaps regarding postoperative analgesia after pediatric posterior spine fusion for adolescent idiopathic scoliosis, a common procedure that results in severe acute postoperative pain. Inadequate analgesia may delay recovery, cause patient dissatisfaction, and increase chronic pain risk. Despite significant adverse effects, opioids are the analgesic mainstay after scoliosis surgery. However, growing emphasis on opioid minimization and enhanced recovery has increased adoption of multimodal analgesia (MMA) regimens. While opioid adverse effects remain a concern, MMA protocols must also consider risks and benefits of adjunct medications. We discuss use of opioids via different administration routes and elaborate on the effect of MMA components on opioid/pain and recovery outcomes including upcoming regional analgesia. We also discuss risk for prolonged opioid use after surgery and chronic post-surgical pain risk in this population. Evidence supports use of neuraxial opioids at safe doses, low-dose ketorolac, and methadone for postoperative analgesia. There may be a role for low-dose ketamine in those who are opioid-tolerant or have chronic pain, but the evidence for preoperative gabapentinoids and intravenous lidocaine is currently insufficient. There is a need for further studies to evaluate pediatric-specific optimal MMA dosing regimens after scoliosis surgery. Questions remain regarding how best to prevent acute opioid tolerance, opioid-induced hyperalgesia, and chronic postsurgical pain. We anticipate that this timely update will enable clinicians to develop efficient pain regimens and provide impetus for future research to optimize recovery outcomes after spine fusion.

The coronal aorto-mesenteric orientation theory for post-operative nausea and vomiting following scoliosis surgery in children: a pilot study

BACKGROUND

Post-operative nausea and vomiting (PONV) is often encountered following corrective scoliosis surgery in children, frequently attributed to high-dose opiate administration. PONV is a frequent cause of prolonged hospital stay. Mechanisms related to transient partial duodenal compression by narrow angulation of the superior mesenteric artery (SMA) and aorta following scoliosis surgery are poorly understood and might be implicated in PONV. This study investigates relationships between biomechanical anatomic variations of the SMA and aorta, and its relationship with clinically significant PONV following scoliosis surgery in children.

METHODS

Children undergoing elective spinal arthrodesis for adolescent idiopathic scoliosis were assessed by preoperative abdominal ultrasound and spinal X-ray prior to surgery. Post-operative assessment of clinically significant PONV is compared to preoperative imaging and clinical variables.

RESULTS

Thirteen patients (11 female and two male), with a mean age of 14 years and 1 month were included. Five patients (38.5%) developed clinically significant PONV. A significant association was observed between the coronal aorto-mesenteric orientation and PONV (P = 0.035). Of the five patients who developed PONV, two had direct coronal angulation of the SMA, one had left angulation and two had right angulation. Patients with significant PONV had narrower aorto-mesenteric distances which approached significance (P = 0.06). No other preoperative variable reached significance.

CONCLUSION

Patients with coronal aorto-mesenteric orientation preoperatively appear at greater risk of developing significant PONV following scoliosis surgery, independent of opiate requirements, prompting consideration of transient partial duodenal obstruction as an important factor in the mechanisms of PONV. A coronal aorto-mesenteric orientation theory (CAMOT) is proposed to explain this biomechanical vascular 'scissor'.

An analysis of the safety and efficacy of dexmedetomidine in posterior spinal fusion surgery for adolescent idiopathic scoliosis: a prospective randomized study

PURPOSE

To evaluate whether use of dexmedetomidine, a centrally acting α2 adrenergic agonist, reduces opioid consumption in PSF.

METHODS

Adolescent idiopathic scoliosis patients who underwent PSF were randomized into morphine (M) and dexmedetomidine (D) group. M group received a 10 μg/kg/h IV infusion of morphine for 24 h post-surgery, while the D group received a 0.4 μg/kg/h IV infusion of dexmedetomidine. Trained nursing staffs recorded hourly vital parameters (blood pressure, pulse rate, respiratory rate, and oxygen saturation). Pain, postoperative nausea/vomiting (PONV), and sedation were rated using: the numerical rating scale (NRS), the PONV scale, and sedation status scale (SS). Preemptive analgesia with gabapentin and postoperative analgesia with ketorolac and paracetamol were used in both the groups. Any complications in the study groups were recorded.

RESULTS

No significant difference was noted between the groups (M vs D) with respect to NRS (3.1 ± 0.8 vs 2.7 ± 0.5) (p = 0.07) and breakthrough analgesia requirements (0.78 vs 0.45) (p = 0.17). A significant difference was noted between the groups with respect to the secondary outcome measures of time to ambulation (56.6 ± 12.7 h vs 45.2 ± 7.7 h), time to oral analgesics (84.3 ± 20 h vs 64.0 ± 15.4 h), and time to liquid intake (8.3 ± 1.3 h vs 7.2 ± 1.2 h). The M group had a higher PONV score (0.46 ± 0.3 vs 0.16 ± 0.1) (p < 0.001) and mean time to bowel opening (112.7 ± 28.4 h vs 90.1 ± 20.5 h) (p < 0.001). Additionally, the enema or suppository requirements for bowel opening were significantly more (0.59 ± 0.6 vs 0.26 ± 0.4) (p = 0.01) in the M group.

CONCLUSION

Dexmedetomidine provided analgesia comparable to morphine with lower PONV scores. It also reduced the opioid requirements in the PSF patients without additional complications and can therefore be incorporated in pain management protocols.

The efficacy of ketamine for postoperative pain control in adolescent patients undergoing spinal fusion surgery for idiopathic scoliosis

The use of ketamine in conjunction with morphine to reduce postoperative pain has been explored in several different surgery subtypes with conflicting results. Ketamine has shown promise to have both opioid sparing and analgesic effects in the postoperative setting. This study aimed to elucidate ketamine's ability to reduce morphine equivalent consumption and improve patient satisfaction after spinal fusion surgery for the correction of idiopathic scoliosis. This surgery is known to be associated with significant postoperative pain which impedes the ability to improve patient satisfaction, and may complicate the recovery timeline. Currently, the standard therapeutic regimen consists of patient-controlled analgesia morphine and the use of other opioids such as hydromorphone. A prospective, randomized double-blinded, placebo-controlled trial was performed to compare the standard morphine equivalent therapy alone against a standard therapy in conjunction with ketamine. Fifty adolescent patients were enrolled and randomized. Results yielded a significant reduction in postoperative morphine equivalent consumption (p = 0.042), adjusted postoperative pain scores (p < 0.001), and incidence of nausea and vomiting (p = 0.045). The application of ketamine as an analgesic in conjunction with the current standard of morphine equivalent therapy may serve as a superior pain control regimen for spinal surgeries in young population. This regimen enhancement may be generalizable to other surgery subtypes within similar populations. LEVEL OF EVIDENCE: Level I.

Role of Ketamine in Multimodal Analgesia Protocol for Bariatric Surgery

Background and Objectives: Acute postoperative pain is one of the most undesirable experiences for a patient in the postoperative period. Many options are available for the treatment of postoperative pain. One of the methods of multimodal analgesia is a combination of opioids and adjuvant agents, such as ketamine. The aim of this study was to evaluate the effect of a pre-incisional single injection of low-dose ketamine on postoperative pain after remifentanil infusion in patients undergoing laparoscopic gastric bypass or gastric plication surgery. Materials and Methods: The prospective, randomized, double-blinded and placebo-controlled trial took place at the Hospital of the Lithuanian University of Health sciences KaunoKlinikos in 2015-2017. A total of 32 bariatric patients (9 men and 23 women) were randomly assigned to receive a single pre-incisional injection of ketamine (0.15 mg/kg (LBM)) (ketamine, K group) or saline (placebo, S group). Standardized protocol of anesthesia and postoperative pain management was followed for all patients. Postoperative pain intensity, postoperative morphine requirements, incidence of side effects and patients' satisfaction with postoperative analgesia were recorded. Results: Thirty-two patients undergoing bariatric surgery: 18 (56.25%; gastric bypass) and 14 (43.75%; gastric plication) were examined. Both groups did not differ in demographic values, duration of surgery and anesthesia and intraoperative drug consumption. Postoperative pain scores were similar in both groups (p = 0.105-0.941). Morphine consumption was 10.0 (7.0-12.5 mg) in group S and 9.0 (3.0-15.0 mg) in group K (p = 0.022). The incidence of side effects was similar in both groups (p = 0.412). Both groups demonstrated very high satisfaction with postoperative analgesia. Conclusions: Pre-incisional single dose ketamine reduces postoperative opioids consumption, but does not have an effect of postoperative pain intensity and side effects after remifentanil infusions. Very high patient satisfaction is achieved if standard multimodal analgesia protocol with an individual assessment of pain and dosage of medications is followed.

An Update on the Basic and Clinical Science of Ketamine Analgesia

OBJECTIVE

In the context of the current opioid epidemic, there has been a renewed interest in the use of ketamine as an analgesic agent.

METHODS

We reviewed ketamine analgesia.

RESULTS

Ketamine is well-known as an antagonist for N-methyl-D-aspartate receptors. In addition, it can regulate the function of opioid receptors and sodium channels. Ketamine also increases signaling through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. These myriad of molecular and cellular mechanisms are responsible for a number of pharmacological functions including pain relief and mood regulation. Clinically, a number of studies have investigated the role of ketamine in the setting of acute and chronic pain, and there is evidence that ketamine can provide analgesia in a variety of pain syndromes.

DISCUSSION

In this review, we examined basic mechanisms of ketamine and its current clinical use and potential novel use in pain management.

Postoperative nausea and vomiting in patients undergoing colorectal surgery within an institutional enhanced recovery after surgery protocol: comparison of two prophylactic antiemetic regimens

BACKGROUND

Enhanced recovery protocols (ERP) provide optimal perioperative care for surgical patients. Postoperative nausea and vomiting (PONV) is common after colorectal surgery (CRS). We aim to compare the efficacy of aprepitant to a cost-effective alternative, perphenazine, as components of triple antiemetic prophylaxis in ERP patients.

METHODS

Patients who underwent ERP CRS at a single institution from July 2015 to July 2017 were evaluated retrospectively. Only subjects who received aprepitant (Group 1) or perphenazine (Group 2) preoperatively for PONV prophylaxis were included. Patient characteristics, simplified Apfel PONV scores, perioperative medications, and PONV incidence were compared between the groups. PONV was defined as the need for rescue antiemetics on postoperative days (POD) 0-5.

RESULTS

Five hundred ninety-seven patients underwent CRS of which 498 met the inclusion criteria. Two hundred thirty-one (46.4%) received aprepitant and 267 (53.6%) received perphenazine. The incidence of early PONV (POD 0-1) was comparable between the two groups: 44.2% in Group 1 and 44.6% in Group 2 (P = 0.926). Late PONV (POD 2-5) occurred less often in Group 1 than Group 2, respectively (35.9% vs. 45.7%, P = 0.027). After matching the groups for preoperative, procedural, and anesthesia characteristics (164 pairs), no difference in early or late PONV could be demonstrated between the groups.

CONCLUSIONS

The incidence of PONV remains high despite most patients receiving three prophylactic antiemetic medications. Perphenazine can be considered a cost-effective alternative to oral aprepitant for prophylaxis of PONV in patients undergoing CRS within an ERP.

Postoperative pain management in patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis: a narrative review

Posterior spinal fusion for adolescent idiopathic scoliosis is one of the most invasive surgical procedures performed in children and adolescents. Because of the extensive surgical incision and massive tissue trauma, posterior spinal fusion causes severe postoperative pain. Intravenous patient-controlled analgesia with opioids has been the mainstay of postoperative pain management in these patients. However, the use of systemic opioids is sometimes limited by opioid-related side effects, resulting in poor analgesia. To improve pain management while reducing opioid consumption and opioid-related complications, concurrent use of analgesics and analgesic modalities with different mechanisms of action seems to be rational. The efficacy of intrathecal opioids and nonsteroidal anti-inflammatory drugs as components of multimodal analgesia in scoliosis surgery has been well established. However, there is either controversy or insufficient evidence regarding the use of other analgesic methods, such as continuous ketamine infusion, perioperative oral gabapentin, acetaminophen, continuous wound infiltration of local anesthetics, a single dose of systemic dexamethasone, and lidocaine infusion in this patient population. Moreover, appropriate combinations of analgesics have not been established. The aim of this literature review is to provide detailed information of each analgesic technique so that clinicians can make appropriate choices regarding pain management in patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion.

Marked attenuation of the amplitude of transcranial motor-evoked potentials after intravenous bolus administration of ketamine: a case report

Background

It is believed that ketamine does not affect motor-evoked potential amplitude, whereas various anesthetic drugs attenuate the amplitude of transcranial motor-evoked potential. However, we encountered a patient with marked attenuation of motor-evoked potential amplitude after intravenous bolus administration of ketamine.

Case presentation

A 15-year-old Japanese girl with a diagnosis of adolescent idiopathic scoliosis was admitted to our hospital to undergo posterior spinal fusion at T4–L3. After induction of general anesthesia using a continuous infusion of propofol and remifentanil, we confirmed that transcranial electrical motor-evoked potentials were being recorded correctly. Ketamine 1.25 mg/kg was administered intravenously for intraoperative and postoperative analgesia. About 3 minutes later, the motor-evoked potential amplitude was markedly attenuated. No other drugs were administered except for ketamine. The patient’s vital signs were stable, and the surgery had not yet started. The motor-evoked potential amplitude was recovered at about 6 minutes after administration of ketamine. The surgery was performed uneventfully, and the patient had no neurologic deficit when she emerged from general anesthesia.

Conclusions

Although there is a widely held belief in the field of anesthesiology that ketamine does not affect motor-evoked potential amplitude, it has been suggested that ketamine could affect its monitoring.

Endogenous Opiates and Behavior: 2016

This paper is the thirty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2016 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Alfentanil versus ketamine combined with propofol for sedation during upper gastrointestinal system endoscopy in morbidly obese patients

Objectives:

To observe the effects of both propofol/alfentanil and propofol/ketamine on sedation during upper gastrointestinal system endoscopy in morbidly obese patients (UGSEMOP).

Methods:

In a prospective, double-blinded, randomized clinical study, 52 patients scheduled for UGSEMOP were assigned to either group A (n=26; 10 µg/kg intravenous [IV] alfentanil) or group K (n=26; 0.5 mg/kg IV ketamine). Each patient was administered 0.7 mg/kg propofol for induction. If it was needed, the patients were administered an additional dose of IV propofol. This study was performed in Sehitkamil State Hospital, Gaziantep, Turkey, between January 2014-2015. Total propofol consumption, time to achieve Modified Aldrete Scores (MAS) of 5 and 10 following the procedure, physician and patient satisfaction scores, and instances of side effects, such as bradycardia and hypotension were recorded.

Results:

Time to onset of sedation and duration of sedation were both significantly shorter in group A. Patients in group A also required less time to achieve an MAS of 5. Total propofol consumption was significantly lower in group A.

Conclusion:

Both propofol/alfentanil and propofol/ketamine combinations provided appropriate hypnosis and analgesia during UGSEMOP. However, propofol consumption was significantly higher using the propofol/ketamine combination.

Effect of ketamine combined with butorphanol on emergence agitation of postoperative patients with gastric cancer

Background

This study aimed to investigate the effect of ketamine combined with butorphanol on emergence agitation (EA) in postoperative gastric cancer patients.

Materials and methods

A total of 150 patients with gastric cancer were included and divided into group B (1 mg butorphanol before anesthesia induction, n=50), group K (1 mg/kg ketamine, n=50), and group C (1 mg butorphanol combined with 1 mg/kg ketamine, n=50). Mean arterial pressure (MAP) and heart rate (HR) at the end of operation, just before extubation (T0) and at 0 minute (T1), 5 minutes (T2), and 30 minutes (T3) after extubation were compared. Statistical analysis of recovery time, extubation time, time in postanesthesia care unit, and EA incidence and adverse reactions were performed.

Results

There were no differences among groups with respect to MAP and HR at T0 and T1 (P>0.05). Compared with patients in group C, significant reduction of MAP and HR were observed in groups K and B at T2 and T3 (P<0.05), while no differences were found between group K and group B (P>0.05). Recovery time, extubation time, time in postanesthesia care unit, and incidence of EA in group C were significantly less than those in groups K and B (P<0.05), but no differences were observed between group K and group B (P>0.05). Total incidence of adverse reactions were significantly increased in group K compared to those in groups C and B (P<0.05).

Conclusion

Injection of ketamine combined with butorphanol before anesthesia induction was more effective than injection of ketamine or butorphanol separately in the prevention of EA.