Preoperative Ketamine Research Articles

Preoperative ketamine administration for prevention of postoperative neurocognitive disorders after major orthopedic surgery in elderly patients: A multicenter randomized blinded placebo-controlled trial

BackgroundPreventive anesthetic impact on the high rates of postoperative neurocognitive disorders in elderly patients is debated. The Prevention of postOperative Cognitive dysfunction by Ketamine (POCK) study aimed to assess the effect of ketamine on this condition. MethodsThis is a multicenter, randomized, double-blind, interventional study. Patients ≥60 years undergoing major orthopedic surgery were randomly assigned in a 1:1 ratio to receive preoperative ketamine 0.5 mg/kg as an intravenous bolus (n = 152) or placebo (n = 149) in random blocks stratified according to the study site, preoperative cognitive status and age. The primary outcome was the proportion of objective delayed neurocognitive recovery (dNR) defined as a decline of one or more neuropsychological assessment standard deviations on postoperative day 7. Secondary outcomes included a three-month incidence of objective postoperative neurocognitive disorder (POND), as well as delirium, anxiety, and symptoms of depression seven days and three months after surgery. ResultsAmong 301 patients included, 292 (97%) completed the trial. Objective dNR occurred in 50 (38.8%) patients in the ketamine group and 54 (40.9%) patients in the placebo group (OR [95% CI] 0.92 [0.56; 1.51], p = 0.73) on postoperative day 7. Incidence of objective POND three months after surgery did not differ significantly between the two groups nor did incidence of delirium, anxiety, apathy, and fatigue. Symptoms of depression were less frequent in the ketamine group three months after surgery (OR [95% CI] 0.34 [0.13–0.86]). ConclusionsA single preoperative bolus of intravenous ketamine does not prevent the occurrence of dNR or POND in elderly patients scheduled for major orthopedic surgery. (Clinicaltrials.gov NCT02892916).

Ketamine induced acute systolic heart failure

Background: Studies have shown major cardiovascular effects associated with ketamine use disorder including dose-dependent negative inotropic effects. Preoperative ketamine use has been linked to ketamine-induced stress cardiomyopathy. Case presentation: A 28-year-old female with a history of recurrent cystitis and ketamine use disorder (twice weekly for 14 years) presented with bilateral lower extremity oedema and shortness of breath for 3 months. She was tachycardic with a troponin level of 0.07 ng/ml and a B-type natriuretic peptide (BNP) level of 2511 pg/ml. Electrocardiogram showed normal sinus rhythm and transthoracic echocardiography (TTE) showed left ventricular ejection fraction (EF) of 15%, dilated left ventricle, and severe tricuspid and mitral regurgitation. Computed tomography (CT) scan of the chest and abdomen showed bilateral pleural effusions with congestive hepatopathy and ascites. The patient was started on intravenous furosemide, metoprolol, and sacubitril/valsartan. Rheumatological workup including complement levels, and antinuclear anti-double-stranded DNA was negative. A repeat TTE 2 weeks later revealed an EF of 25% and moderate tricuspid regurgitation. Four months later, the EF was 54% with normal left ventricular cavity size. Conclusion: Although ketamine use disorder is increasing, data on long-term side effects is minimal. Screening for ketamine use disorders should be considered in patients presenting with acute systolic heart failure. Long-term studies are needed to evaluate the benefits of adding ketamine screening to standard urine toxicology.

Comparing the use of Preoperative Ketamine or Midazolam or Ketamine versus Oral Dextromethorphan for Reducing Sevoflurane Emergence Agitation among Preschool Children Undergoing Adenotonsillectomy

Comparing the use of Preoperative Ketamine or Midazolam or Ketamine versus Oral Dextromethorphan for Reducing Sevoflurane Emergence Agitation among Preschool Children Undergoing Adenotonsillectomy

Comparative Study of Effect of Preoperative Ketamine and Magnesium Sulphate Nebulization in Reducing the Incidence and Severity of Post Operative Sore Throat after Tracheal Intubation A Double Bind Randomized Control Study

Comparative Study of Effect of Preoperative Ketamine and Magnesium Sulphate Nebulization in Reducing the Incidence and Severity of Post Operative Sore Throat after Tracheal Intubation A Double Bind Randomized Control Study

Pharmacological prevention of postoperative delirium in patients undergoing cardiac surgery: a bayesian network meta-analysis.

The incidence of postoperative delirium in patients undergoing cardiac surgery is very high and increases morbidity and mortality. The possibility of pharmacological means to reduce its incidence is very attractive. At present, there is still no clear demonstration that any drug can prevent postoperative delirium in these patients. The aim of this Bayesian network meta-analysis (NMA) was to evaluate whether there is evidence that a drug is effective in reducing the incidence of POD in cardiac surgical patients. Our NMA showed that preoperative ketamine at subanesthetic doses can significantly reduce the incidence of POD. Risperidone also decreases the incidence of POD, but not significantly.

Comparative study between ketamine versus betamethasone gargles in attenuating post-operative sore throat after endotracheal intubation

: Postoperative sore throat (POST) is a commonly encountered side effect which causes patient discomfort after airway instrumentation during general anesthesia (GA). This study was conducted to investigate the efficacy of preop­erative gargling with Ketamine, a NMDA receptor an­tagonist and Betamethasone gargles, a steroidal anti inflammatory drug in reducing POST in patients being intubated for surgery under GA. This was a randomized, single blinded, prospective study conducted after obtaining the Institutional Ethics Committee approval. 90 patients undergoing surgery under GA with endotracheal intubation were enrolled in the study after obtaining written informed consent from all. They were further divided into 3 groups; group B, group K and group C who received Betamethasone gargles, Ketamine gargles and Dextrose Saline gargles respectively, 5 minutes before GA. Results obtained were compared statistically by using Kruskal-Wallis test, which showed significant difference between median POST grading. The Mann-Whitney U test was used for the statistical intergroup analysis. There was no statistical difference among groups as far as age, height, weight by using ANOVA test; p value > 0.05. Age of patients varied between 16-60 years in three groups. The severity of sore throat were noticeably reduced after Ketamine, Betamethasone gargles in group K and group B (p < 0.05) as compared to group C when statistically analysed by Mann-Whitney U test. But Betamethasone gargles in group B patients more efficiently reduced the incidence, severity of sore throat compared to Ketamine gargles (p<0.05) during postoperative period. The incidence & severity of POST decreased with use of pre-operative Ketamine gargles or Betamethasone gargles during post-operative period in patients with tracheal intubation. The Betamethasone gargles were more effective than Ketamine gargles in reducing the incidence, severity of POST.

Pre operative nebulization with ketamine decreases incidence and severity of post-operative sore throat

Postoperative sore throat (POST) is unavoidable outcome of endotracheal intubation, occurs in 21-65% of the patients. There are some pharmacological and non-pharmacological methods for prevention of POST. Nebulization is better as small volume of drug required for effect, easy way of administration, better patient compliance and most importantly no risk of aspiration as seen with gargle. Method: 100 patients of ASA grading I and II, aged between 20-60 years undergoing general anaesthesia on elective basis were randomly divided in two groups. 50 patients received pre-operative nebulization with 1.0ml ketamine (50mg) with 4.0ml normal saline while others received nebulization with 5ml normal saline for 15 min. General anesthesia was given. The POST and hemodynamic monitoring were done pre-nebulization, pre-induction, on reaching post-anaesthesia care unit and till 24 h post-operatively. Results: Incidence of POST was reduced with ketamine nebulization. The primary outcome was incidence of POST significantly reduced in group K till 24 h post operatively.Conclusion: Preoperative ketamine nebulization is simple, safe and effectively reduced the incidence and severity of POST, with no adverse effects.

A Comparative Evaluation of the Effect of Preoperative Ketamine and Tramadol Nebulisation on Post Operative Sore Throat after Endotracheal Intubation

Background: Postoperative sore throat (POST) is a common complaint during postoperative period after tracheal intubation. We evaluated and compared the effects of preoperative ketamine or tramadol nebulization on POST in patients undergoing general anaesthesia with tracheal intubation. Methods: Sixty patients, aged 18-60 years of ASA status 1 & 2 scheduled for elective surgery lasting upto 2 hours under general anaesthesia with endotracheal intubation were randomly divided into two groups; Group K: patients received Ketamine 50 mg (1 ml) with normal saline (4 ml) nebulisation, Group T: patients received Tramadol 50 mg (1 ml) with normal saline (4 ml) nebulization 30 min before induction. Incidence of postoperative sore throat and its intensity, nausea vomiting, sedation and any side effects of drugs were recorded. Result: No significant difference was observed in the incidence of postoperative sore throat between the ketamine group and tramadol group patients. Severity of POST was higher in group T as compared to group K but it was statistically insignificant. Nausea, vomiting and sedation incidence was comparable in both groups. Conclusion: Preoperative nebulisation with ketamine is clinically more effective than tramadol nebulization in prevention of postoperative sore throat.

Effect of Preoperative Ketamine Nebulisation on Attenuation of Incidence and Severity of Postoperative Sore Throat, Hoarseness of Voice and Cough: A Randomised Double-Blind Study

Effect of Preoperative Ketamine Nebulisation on Attenuation of Incidence and Severity of Postoperative Sore Throat, Hoarseness of Voice and Cough: A Randomised Double-Blind Study

Tourniquet Complications in an Upper Extremity Orthopedic Surgery Patients

Abstract An arterial tourniquet is a pneumatic device consisting of an inflated cuff connected to a supply of compressed gas. The most common use for these tourniquets is in surgical procedures on the extremities, where the tourniquet is very useful in optimizing the operating conditions by creating a bloodless surgical field. However, the exsanguination process followed by ischemia will result in physiological problems with local and systemic consequences. The patient in the case to be discussed is a 54-year-old woman with a diagnosis of implant loosening et causa nonunion left Montegia fracture who was scheduled for implant revision surgery. From these cases, it is possible that the patient experienced tourniquet-induced hypertension, which is one of the systemic complications that can arise due to the use of the tourniquet. It is said that tourniquet-induced hypertension is often difficult to control and is resistant so it is difficult to lower it. Emerging hypertension may not present a significant problem in young, noncomorbid patients, but in these patients with comorbid of hypertensive heart disease (HHD), elevated blood pressure can be very detrimental. Preoperative ketamine, clonidine, or lidocaine has been used to prevent tourniquet pain, which can lead to increased arterial pressure that is difficult to control. The anesthetist is also obliged to monitor the duration and pressure applied by the tourniquet so that it is not excessive so that detrimental complications can be prevented.

Preoperative Ketamine and Perioperative Depression

Preoperative Ketamine and Perioperative Depression

Comparative study between preoperative ketamine bolus dose versus ketamine bolus plus infusion for perioperative analgesia in orthopedic surgery

Background and aim Postoperative pain severity depends on patient factors, anesthesia-related factors, and type of surgery. Pain after orthopedic surgery has been found to be immediate and severe, which necessitates more attention for its management. The aim of this study was assessment of the effectiveness of intravenous ketamine to provide postoperative analgesia after orthopedic surgery. This randomized double-blind study had been performed in Al-Zahraa University Hospital from December 2019 to October 2020. Patients and methods A total of 75 patients subjected to major orthopedic surgery were registered in the study. The patients had been randomly assigned into three equal groups (control, bolus, and bolus with infusion groups) to receive intravenous ketamine bolus dose alone (0.3 mg/kg) (bolus group); ketamine bolus (0.3 mg/kg) plus infusion (5 µg/kg/min), which terminated at the end of operation (bolus with infusion group); or placebo in the form of normal saline (control group). Visual analog pain scale score, postoperative 24 h morphine requirements, time to first analgesic requirement, and postoperative adverse effects were recorded and compared. Results Postoperative visual analog pain scale score and total morphine requirements were significantly less in bolus with infusion group, followed by bolus group, whereas the highest score and requirements were in control group. Regarding the time to first analgesic requirement, there was a statistically significant increased time to first analgesic in bolus with infusion group, followed by bolus group, whereas the shortest time was in control group, and there were nonsignificant differences among groups regarding postoperative complications. Conclusion Ketamine bolus dose alone before skin incision or followed by infusion had the capability of decreasing postoperative pain and total analgesic requirement and increasing the time to first analgesic requirement after orthopedic surgery, with superiority of ketamine bolus dose plus infusion without increasing the incidence of adverse effects.

Effect of Preoperative Ketamine and Magnesium Sulfate on Intra & Postoperative Analgesia in Laparoscopic Cholecystectomy: A Comparative Randomized Controlled Study

Effect of Preoperative Ketamine and Magnesium Sulfate on Intra & Postoperative Analgesia in Laparoscopic Cholecystectomy: A Comparative Randomized Controlled Study

Magnesium Sulfate Nebulizer versus Ketamine Nebulizer in Decreasing Incidence and Severity of Post Operative Sore Throat with Endotracheal Intubation in Adults

Background: Endotracheal intubation is the prominent cause of airway mucosal injury which results in postoperative sore throat (POST), with an incidence of 21%–65%. Although this complication is minor, if left unresolved, it produces significant agony and annoyance to the patient. Aim of the Work: to compare efficacy of magnesium/ nebulizer versus ketamine nebulizer in decreasing postoperative sore throat incidence, severity and duration with fixed endotracheal tube intra cuff pressure at or below 20 cm H2O using handheld tracheal cuff pressure monitor in adults ASA (American Society of Anesthesiologists) I-II in 20-60 years age group of either sex in operations less than 2 hours. Methodology: our study included 90 adult patients, status I-II (ASA I-II) in the age group 20-60 years, of either sex undergoing operation under general anesthesia (GA) scheduled for a day case surgery and operation time less than 2 hours with fixation of endotracheal tube cuff at 20 cm H2O using hand held tracheal cuff pressure monitor (Pressure Gauge) and checked every half hour till end of surgery and maintained at or below 20 cm H2O. Results: Our study showed reduction in POST incidence and severity after preoperative magnesium sulfate nebulization in all time points 0, 2, 4, 8, 12 and 24 hours postoperative, so it was proved that magnesium nebulizer has great role in reduction of incidence, severity and duration of POST. Conclusion: we concluded that preoperative magnesium sulfate nebulization reduce incidence and severity of POST and it is more effective than preoperative ketamine nebulization.

The effect of using pre-operative ketamine injection on post-tonsillectomy pain intensity in children

Introduction: Tonsillectomy in children is associated with some major complications originating from intense post-tonsillectomy pain which can distress patients, cause swallowing difficulties and discomfort, and also lead to aspiration. Thus, this study aimed to investigate the effect of using pre-operative ketamine injection on post-tonsillectomy pain intensity in children.
 Methods: This double-blind clinical trial was carried out on 60 patients undergoing elective tonsillectomy. To this end, all the patients were anaesthetized by the same method. In the first group, 2 cc of ketamine (0.5mg/kg) solution was topically injected into the soft tissue of tonsillar fossa (peritonsillar space); in the second group, a similar administration was performed but with normal saline. For all the patients, incision was made 5 minutes after injection with the Blast Dissection Snare method. Moreover, the patients’ pain intensity and analgesics consumption were measured 30 minutes, and 1, 2, 4, and 6 hours after surgery. Finally, the collected data were analyzed using the SPSS software.
 Results: The present study was conducted on 60 patients, 37 males and 23 females, with the mean age of 9.3±3.4 years. In this respect, repeated measures analysis of variance of patients’ pain scores collected in five post-operative stages showed that pain intensity in both groups was at the highest level immediately after operation; it gradually decreased during measurement stages. However, at each measurement, the pain intensity experienced in the ketamine-treated group was significantly lower than that for the placebo group.
 Conclusion: It was concluded that pre-incision topical injection of ketamine can serve as an effective method to control post-tonsillectomy throat pain.

Preoperative ketamine nebulization attenuates the incidence and severity of postoperative sore throat: A randomized controlled clinical trial.

Background:Endotracheal intubation is the prominent cause of airway mucosal injury which results in postoperative sore throat (POST), with an incidence of 21%–65%. Although this complication is minor, if left unresolved, it produces significant agony and annoyance to the patient. This study was conducted to evaluate the efficacy of nebulized ketamine in decreasing POST.Materials and Methods:After written informed consent, 96 patients of the American Society of Anesthesiologists physical status (PS) 1–2 between 18 and 60 years, of either sex undergoing general anesthesia (GA) with tracheal intubation were enrolled in this prospective, randomized, placebo-control, and double-blind controlled trial. Patients were randomized into two groups; Group 1 received ketamine 50 mg (1.0 ml) with 4.0 ml of saline nebulization, while Group 2 received saline nebulization 5.0 ml for 15 min. GA was administered 15 min after completing nebulization. On reaching postanesthesia care unit, POST monitoring was done at 0, 2, 4, 6, 12, and 24 h after extubation. POST was graded on a four-point scale (0–3).Results:The overall incidence of POST in this study was 25%: POST was experienced by 7 patients (14.6%) in ketamine and 17 patients (35.4%) in saline group (Fisher's exact P = 0.018). There was statistically significant reduction in the incidence of POST in ketamine group when compared to saline, at 2, 4, 6,12, and 24 h postoperatively (P < 0.05*). Severity of sore throat was also higher in saline group when compared to ketamine at 4 h (P = 0.030*) and 6 h (P = 0.016*) postextubation.Conclusion:Preoperative ketamine nebulization effectively reduced the incidence and severity of POST, with no adverse effects.

Evaluation of Two Protocols for Analgesia during Total Unilateral Mastectomy in Bitches

Background: Proper evaluation of pain is essential to select effective anesthetic protocols in surgical procedures in animals. Pain assessment can be accomplished during the perioperative period by measuring several physiological parameters, such as heart and respiratory rates. Measuring serum levels of cortisol and glucose is one of the most commonly used methods to assess the effectiveness of protocols for pain control. The aim of this study was to compare two analgesic protocols in dogs undergoing unilateral total mastectomy, a surgery that can cause moderate-to-severe pain in dogs. Materials, Methods &amp; Results: Eighteen female dogs seen at the Veterinary Hospital of the University of Southern Santa Catarina, Brazil, were recruited for this study, without stratification by breed and age, except for brachycephalic breeds. The animals were divided into two groups: 1) FLK group, in which the animals received preoperative ketamine (5 mg/ kg, IM) and midazolam (0.3 mg/kg, IM), an IV bolus of fentanyl (0.004 mg/kg), lidocaine (2 mg/kg) and ketamine (0.5 mg/kg), and then a combination of fentanyl (0.008 mg/kg/h), ketamine (0.6 mg/kg/h) and lidocaine (2 mg/kg/h) diluted in normal saline solution were infused at a rate of 10 mL/kg/h until the end of the surgical procedure; 2) AM group, in which the animals received preoperative morphine (0.5 mg/kg, IM) and acepromazine (0.05 mg/kg, IM). In both groups, anesthesia was induced by using propofol (6 mg/kg, IV) and maintained with isoflurane. Blood samples were collected by jugular venipuncture (4 mL) in the preoperative and postoperative periods to evaluate serum levels of cortisol and glucose. Statistical analysis was carried out using the two-way analysis of variance (ANOVA) for repeated measures, followed by the Tukey test (P &lt; 0.05). Cortisol levels showed no significant difference between pre- and postoperative periods. Glucose levels showed a significant difference between pre- and postoperative periods in the AM group (P = 0.001). The respiratory rate showed a significant difference between groups at 10 (T10) min after induction (P &lt; 0.001). Discussion: In this study, 67% of the experimental animals were mixed-breed dogs. The average weight was 16.9 ± 10.1 kg. The most frequent age group seen at the Veterinary Hospital was 8-10 years, which is in accordance with other published studies on female dogs with mean age of 10 years. The significant difference in the respiratory rate at T10 can be explained by the respiratory depression caused by a bolus administration of fentanyl in the FLK group. Both protocols were similar in this study; however, higher values of cortisol and glucose, even above the physiological reference values, were observed in the AM group as compared to the FLK group. These higher values must be taken into consideration due to their clinical importance, given that consequences of stress include several deleterious effects, such as immunosuppression, delayed wound healing, and acceleration of disease processes. Findings from this study indicate that the use of a multimodal analgesia protocol, such as the one used in the FLK group, is probably the best alternative for patients submitted to unilateral total mastectomy.

Preoperative Oral Morphine and Sub-Anesthetic Ketamine Co-Administration Reduce Acute Post-Mastectomy Pain

Objectives: To assess the analgesic efficacy and tolerability of co-administration of pre-emptive single oral dose of sustained release morphine and sub- anesthetic ketamine infusion for modified radical mastectomy (MRM) with axillary evacuation. Methods: Sixty four adult female patients scheduled for MRM were divided to two groups, morphine group (n=32) received preoperative oral sustained release morphine tablet, 30 mg and placebo group (n=32) received placebo tablet. Both groups received preoperative ketamine bolus, 0.5 mg/kg followed by continuous infusion 0.1 mg/kg/h for 24 h postoperatively. VAS pain score, time to first analgesic request, 24 h analgesic consumption were reported. Results: The mean VAS pain score during movement was significantly decreased in morphine group in comparison to placebo group from 2 h till 72 h postoperatively, 2 h (2.87 ± 1.0 vs. 4.53 ± 1.67) mean difference (-1.67) (95% CI)-(2.38-0.95), 72 h (1.20 ± 0.76 vs. 1.83 ± 0.91) mean difference (-0.63) (95% CI)-(1.07-0.20) while the mean VAS pain score during rest was significantly decreased in morphine group in comparison to placebo group from 2 h till 24 h postoperatively, 2 h (2.03 ± 0.85 vs. 3.47 ± 0.93) mean difference (-1.33) (95% CI)-(1.78-0.90), 24 h (1.40 ± 0.72 vs. 1.77 ± 0.68) mean difference (-0.37) (95% CI)-(0.73-0.01). The median (IQ) time to first analgesic request was significantly delayed in morphine group in comparison to placebo group, 11.8 (9.7:14.2) h vs. 2.3 (2.1:2.5) h, (P<0.001). The number (percentage) of patients required paracetamol in the first postoperative 24 h was significantly lower in morphine group in comparison to placebo group, 10 (33%) vs. 30 (100 %) (P<0.001). Conclusion: Analgesic technique based on pre-emptive sustained release oral morphine and perioperative infusion of sub-anesthetic dose of ketamine provides satisfactory analgesia for patients undergoing MRM.

Efficacy of Ketamine Gargles in the Prevalence of Postoperative Sore Throat after Endotracheal Intubation

Background: Postoperative sore throat is a common and disturbing complication after endotracheal intubation, leading to patient discomfort and dissatisfaction. Objective: To find out the efficacy of ketamine gargles in reducing the incidence and severity of postoperative sore throat after endotracheal intubation. Material and method: We studied the role of pre-operative ketamine gargles for reducing postoperative sore throat. Patients undergoing elective abdominal and pelvic surgery under general anaesthesia with endotracheal tube were included in the study. They were randomly allocated in two groups, each group comprising of 30 patients. Group 1(K) received preservative free ketamine 50mg in 29 ml distilled water. Group 2(C) gargled with 30 ml distilled water. Patients were asked to gargle for 30 seconds, 5minutes before induction of anaesthesia. Postoperatively sore throat was assessed at 0, 4, 8 and 24 hours after extubation. The severity of sore throat was assessed from mild to severe. Results: Immediately after extubation, 90% patients in group C had sore throat compared to 66.7% in group K. 24 hours after extubation, the incidence decreased to 50% in group C and 13.3% in group K. Similar decrease incidence was noted at 4 and 8 hours post extubation in group K. No patient in group K complained of change in voice or hoarseness of voice. Conclusion: We found that preoperative gargling with ketamine is a simple and cost effective way to reduce the incidence and severity of postoperative sore throat. Key words: Abdominal and pelvic surgery, endotracheal intubation, ketamine gargles, postoperative sore throat

Efficacy of ketamine in improving pain after tonsillectomy in children: meta-analysis.

Background and objectivesThe goal of this meta-analysis study was to perform a systematic review of the literature on the effects of ketamine on postoperative pain following tonsillectomy and adverse effects in children.Subjects and MethodsTwo authors independently searched three databases (MEDLINE, SCOPUS, Cochrane) from their inception of article collection to February 2014. Studies that compared preoperative ketamine administration (ketamine groups) with no treatment (control group) or opioid administration (opioid group) where the outcomes of interest were postoperative pain intensity, rescue analgesic consumption, or adverse effects (sedation, nausea and vomiting, bad dream, worsening sleep pattern, and hallucination) 0–24 hours after leaving the operation room were included in the analysis.ResultsThe pain score reported by the physician during first 4 hours and need for analgesics during 24 hours postoperatively was significantly decreased in the ketamine group versus control group and was similar with the opioid group. In addition, there was no significant difference between ketamine and control groups for adverse effects during 24 hours postoperatively. In the subgroup analyses (systemic and local administration) regarding pain related measurements, peritonsillar infiltration of ketamine was more effective in reducing the postoperative pain severity and need for analgesics.ConclusionPreoperative administration of ketamine systemically or locally could provide pain relief without side-effects in children undergoing tonsillectomy. However, considering the insufficient evaluation of efficacy of ketamine according to the administration methods and high heterogeneity in some parameters, further clinical trials with robust research methodology should be conducted to confirm the results of this study.