Effect Of Low-dose Ketamine Research Articles

Effect of low dose ketamine versus dexmedetomidine on gag reflex during propofol based sedation during upper gastrointestinal endoscopy. A randomized controlled study

ObjectiveThe aim of this study is to evaluate the effect of dexmedetomidine versus low dose ketamine on incidence of gag reflex and the total amount of propofol consumed during (UGIE) in patient sedated with propofol.MethodsThis randomized, prospective, double blind study was approved by institutional ethics committee of El-Minia university hospital and carried out in the period ranged from March 2015 to January 2016. 75 male and female patients aged from 18 to 70 years old, ASA class I–II. The patients were randomly (by computer generated table) allocated into 3 equal groups: Group(I) (propofol group), Group(II): (propofol + ketamine group), Group(III): (propofol + dexmedetomidine group). Parameters assessed was - Gag reflex, depth of sedation, total dose of propofol, oxygen saturation(spo2), hemodynamic data, time to recovery, any side effects as:- emergence delirium, and ny need for airway assistance.ResultsGag reflex In group(I) was 32% (8 patients) versus 20% (5 patients) in group(II) and 8% (2 patients) in group(III). Patients in group(I) were significantly required higher doses of propofol when compared to group(III) and group(II), while patients in group(II) were required higher doses of propofol than group(III) with significant statistically difference. The changes of HR were comparable between the studied groups except after 2 min of induction, there were significant reduction in mean values of HR in group(I) in comparison to group(II) and group(III). As regard MAP, there were significant elevation in group(II) when compared to group(I) (at 2, 4, 6 min) and group(III) (at 2, 4, 6, 8 min, otherwise there were no significant difference. Oxygen saturation was comparable in the studied groups at all set time and there was no significant difference in their values, only 8% of patients in group(II) versus 12% in group(III) and 20% in group(I) needed jaw thrust as airway assistance. Time to recovery in group(I) was (4.84 ± 0.89 min) which was significantly longer than both group(II) (4.16 ± 1.06 min) and group(III) (4.2 ± 1.04 min).ConclusionDexmedetomidine with propofol in patients undergoing UGIE was safe and effectively, can reduce the incidence of gag reflex better than ketamine when added to propofol, with less propofol consumption and better in recovery time.

Breaking Sad: Unleashing the Breakthrough Potential of Ketamine's Rapid Antidepressant Effects.

Preclinical Research The surprising results of a small clinical trial on the effects of low dose ketamine, a 65-year old anesthetic drug that is also used off-label for chronic pain and recreationally as a club drug, in eight depressed subjects unleashed the most significant advance in antidepressant drug development in decades. That study and subsequent ones have demonstrated that low dose, infused ketamine is able to induce a remission of depression in patients who have failed conventional medications, within 24 h. The apparent increased efficacy and rapid onset of effect of ketamine distinguish it from all other current antidepressant treatments. However, a single infusion of subanesthetic doses of ketamine produces benefits that typically last <3 weeks. The infusions are associated with a transient "psychedelic" experience and increased blood pressure that requires monitoring. There is also a theoretical potential to induce ketamine addiction. These features limit ketamine's ability to be a widely used treatment for depression and thus limit is ability to have a meaningful impact on the heavy morbidity and mortality associated with this disorder, despite its "breakthrough" rate of efficacy and speed of action. While growing numbers of clinicians are using ketamine to treat treatment resistant depression, many in the depression field believe that the aforementioned limiting aspects need to be separated from its remarkable therapeutic effects in order to unlock the breakthrough potential of this agent. To that end, drug development efforts have focused on various features of ketamine as targets for optimization including its modulation of the NMDA receptor, its pharmacokinetics, its chirality and its active metabolites including HNK (2R, 6R)-hyroxynorketamine. Drug Dev Res 77 : 489-494, 2016. © 2016 Wiley Periodicals, Inc.

The Effects of Low-Dose Ketamine on Acute Pain in an Emergency Setting: A Systematic Review and Meta-Analysis.

ObjectivesCurrently ketamine is not used often as an analgesic in the emergency department (ED). Nonetheless, it can increase the efficiency of opioids and decrease their side effects. The purpose of this systematic review and meta-analysis was to evaluate whether low-dose ketamine in the ED provides better analgesia with fewer adverse effects.MethodsThe PubMed, EMBASE, and Cochrane Library databases were searched by two reviewers independently (last search performed on January 2016). Data were also extracted independently.ResultsA total of 6 trials involving 438 patients were included in the current analysis. Our subgroup analysis of pain reduction indicates that the favorable effects of ketamine were similar or superior to those of placebo or opioids, although these effects were heterogeneous. However, low-dose ketamine was associated with a higher risk of neurological (relative risk [RR] = 2.17, 95% confidence interval [CI] = 1.37–3.42, P < 0.001) and psychological events (RR = 13.86, 95% CI = 4.85–39.58, P < 0.001). In contrast, the opioid group had a higher risk of major cardiopulmonary events (RR = 0.22, 95% CI = 0.05–1.01, P = 0.05).ConclusionsThe efficiency of ketamine varies depending on the pain site, but low-dose ketamine may be a key agent for pain control in the ED, as it has no side effects. It may also help to reduce the side effects of opioids.

The effect of low-dose ketamine via patient-controlled analgesic pump on morphine consumption in the postoperative period in thoracotomies: a systematic review protocol.

The objective of this systematic review is to determine if adding low-dose ketamine to a morphine patient-controlled analgesic pump will have an impact on the total consumption of morphine during the first 72 hours postoperative in patients over the age of 15 undergoing surgery involving thoracotomy. In addition, secondary outcomes assessing the impact on pain, nausea and vomiting will be evaluated for any alteration with ketamine co-administration.

Antidepressant-like effect of low dose ketamine and scopolamine co-treatment in mice

Current medications for depression typically require weeks of treatment before significant clinical improvement is observed, and are only effective in a relatively small subset of patients. Recent human clinical studies have demonstrated that ketamine, an NMDA receptor antagonist, and scopolamine, a muscarinic acetylcholine receptor antagonist, produce rapid antidepressant responses within hours of administration, and are effective in treatment-resistant patients. We hypothesize that efficacy and tolerability may be improved by combining lower doses of both drugs in the treatment of depression. We therefore conducted a preclinical study in mice to assess whether co-treatment of low doses of scopolamine and ketamine that alone are ineffective has antidepressant-like effects in the forced swim test (FST), an assay with predictive validity for antidepressant drugs. Whereas single administration of ketamine (3mg/kg intraperitoneal [i.p.]) or scopolamine (0.1mg/kg i.p.) did not reduce immobility time in the FST, co-administration of both drugs at these doses significantly reduced immobility time by 45% compared to vehicle treated controls. These results suggest that the combination of subeffective doses of ketamine and scopolamine may prove efficacious for the treatment of depression and should be evaluated in human clinical trials.

The effects of low-dose ketamine on the prefrontal cortex and amygdala in treatment-resistant depression: A randomized controlled study.

Low-dose ketamine has been found to have robust and rapid antidepressant effects. A hypoactive prefrontal cortex (PFC) and a hyperactive amygdala have been suggested to be associated with treatment-resistant depression (TRD). However, it is unclear whether the rapid antidepressant mechanisms of ketamine on TRD involve changes in glutamatergic neurotransmission in the PFC and the amygdala. A group of 48 TRD patients were recruited and equally randomized into three groups (A: 0.5 kg/mg-ketamine; B: 0.2 kg/mg-ketamine; and C: normal saline [NS]). Standardized uptake values (SUV) of glucose metabolism measured by (18) F-FDG positron-emission-tomography before and immediately after a 40-min ketamine or NS infusion were used for subsequent region-of-interest (ROI) analyses (a priori regions: PFC and amygdala) and whole-brain voxel-wise analyses and were correlated with antidepressant responses, as defined by the Hamilton depression rating scale score. The (18) F-FDG signals were used as a proxy measure of glutamate neurotransmission. The ROI analysis indicated that Group A and Group B, but not Group C, had increases in the SUV of the PFC (group-by-time interaction: F = 7.373, P = 0.002), whereas decreases in the SUV of the amygdala were observed in all three groups (main effect of time, P < 0.001). The voxel-wise analysis further confirmed a significant group effect on the PFC (corrected for family-wise errors, P < 0.05; post hoc analysis: Group A<Group C, Group B<Group C). The SUV differences in the PFC predicted the antidepressant responses at 40 and 240 min post-treatment. The PFC changes did not differ between those with and without side effects. Ketamine's rapid antidepressant effects involved the facilitation of glutamatergic neurotransmission in the PFC.

Single Intraperitoneal Injection of Low-Dose Ketamine Pretreatment Alleviates Mechanical Hyperalgesia and Downregulates the Expression of Inflammatory Cytokines in Spinal Dorsal Horn of Rats

Background: Various common surgeries, such as thoracotomy and inguinal hernia repair which involve essential prolonged tissue retraction, often evoke chronic postoperative pain (CPOP). They bring great pain to patients, and make the qualities of their lives lower. The concrete mechanism of CPOP has still been unclear, and lacks effective research methods. To solve this problem, a new rat model was developed, whereby skin/muscle incision and retraction (SMIR) in the medial thigh of rat evoked CPOP to simulate clinical scene. Many studies provided evidence that CPOP often is accompanied with a large number of inflammatory cytokines releasing, and these cytokines induce or facilitate inflammatory hyperalgesia. In the present study, we investigated the expression of inflammatory cytokines in a SMIR rat model and examined the effects of low-dose ketamine pretreatment.Methods: Paw withdrawal mechanical threshold (PWMT) was used to assess mechanical hyperalgesia 1 day before and 1, 3, 7, 10, 14, 21, and 28 days after a SMIR operation. Western blotting was used to investigate the expression of interleukin (IL)-1, IL-6, IL-17, and tumor necrosis factor (TNF)-α at the spinal level.Results: SMIR rats developed long-lasting mechanical hyperalgesia, companied with the upregulation of inflammatory cytokines at the spinal level. A single intraperitoneal injection of low-dose ketamine before SMIR surgery could alleviate mechanical hyperalgesia significantly and downregulate the expression of IL-1, IL-6, IL-17, and TNF-α at the spinal level.Conclusions: Our data suggested that the expression of IL-1, IL-6, IL-17, and TNF-α at the spinal level in the rats of SMIR-induced CPOP were upregulated, and a single pre-intraperitoneal injection of low-dose ketamine could alleviate mechanical hyperalgesia and downregulate the expression of inflammatory cytokines in spinal dorsal horn. This might be a novel target for CPOP therapy. Citation: Li Xu, Yu Shen, Lin Liu, Yin Cui, Xiao-Ping Gu, Zheng-Liang Ma. Single intraperitoneal injection of low-dose ketamine pretreatment alleviates mechanical hyperalgesia and downregulates the expression of inflammatory cytokines in spinal dorsal horn of rats after skin/muscle incision and retraction. J Anesth Perioper Med 2015; 2: 236-43. doi: 10.24015/JAPM.2015.0032This is an open-access article, published by Evidence Based Communications (EBC). This work is licensed under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium or format for any lawful purpose. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Comparison of the preemptive analgesia of low dose ketamine versus magnesium sulfate on parturient undergoing cesarean section under general anesthesia

ObjectiveTo investigate the efficacy of the preemptive analgesic effect of low dose ketamine versus MgSO4 on potentiating postoperative analgesia when compared to placebo in patients undergoing cesarean section under general anesthesia.MethodsThis prospective randomized blind study included 60 parturient females scheduled for cesarean section under general anesthesia. They were randomized into three equal groups [20 patients each]: group I [Control]: received 20 ml normal saline 0.9%, group II [Ketamine]: received ketamine 0.3 mg/kg in 20 ml normal saline and group III [MgSO4]: received MgSO4, 30 mg/kg in 20 ml normal saline. Investigated medications infused over 10 min before induction of anesthesia. Fentanyl requirement, mean BP and HR were measured intraoperatively. Pain, sedation and nausea and vomiting were assessed at 2, 6, 12 and 24 h postoperatively. Total postoperative pethidine dose over 24 h was calculated.ResultsMBP and HR showed statistically significantly lower value in group (K) and (M) compared to group (C) at postintubation and postincision readings. Intraoperative fentanyl requirement was statistically higher in (C) groups compared to (K) and (M) groups. The time for first request for postoperative analgesia was longer and the total postoperative pethidine dose over 24 h was lower in (K) group compared to (C) and (M) groups. Postoperative VAS scores at 2 and 6 h postoperatively showed statistically highly significantly lower values in (K) group compared to (C) and (M) groups. Apgar, postoperative sedation and PONV scores showed no statistically significant differences among the three groups.ConclusionsPreemptive dose of either ketamine (0.3 mg/kg) or MgSO4 (30 mg/kg) in patients undergoing cesarean section under general anesthesia could suppress the pressor response to endotracheal intubation and skin incision and decreased the intraoperative fentanyl requirement. Ketamine showed a significant preemptive analgesic effect compared to MgSO4 at 2 and 6 h postoperatively.

Effect of low dose ketamine versus dexamethasone on intraoperative nausea and vomiting during cesarean section under spinal anesthesia

ObjectivesThe purpose of our study was to evaluate the prophylactic use of low dose ketamine and comparing it to dexamethasone for reducing intraoperative nausea and vomiting (IONV) during cesarean section under spinal anesthesia.MethodsThe study was performed in 135 full term parturient women of ASA I & II (American Society of Anesthesiology Grade I & II), aged between 20 and 40 years with uncomplicated pregnancies. The group I (n = 45) received 0.4 mg/kg ketamine, group II (n = 45) received 8 mg dexamethasone while control group III (n = 45) received 5 ml normal saline, slowly IV immediately after spinal anesthesia and before surgical incision. The number of episodes of nausea and vomiting was recorded, as well as any other adverse effects.ResultsThe results of this study showed that the rate of nausea and vomiting was lower in patients who received 0.4 mg/kg ketamine and 8 mg dexamethasone than in the placebo group with significant reduction in hypotensive episodes in ketamine group (P = 0.02).ConclusionLow dose ketamine is effective as dexamethasone in prevention of IONV during cesarean section under spinal anesthesia.

The effects of low-dose ketamine on the analgesia nociception index (ANI) measured with the novel PhysioDoloris™ analgesia monitor: a pilot study.

The PhysioDoloris™ analgesia monitor assesses nociception effects on the autonomic nervous system by analyzing changes in heart rate variability (HRV). This non-invasive device analyses ECG signals and determines the analgesia nociception index (ANI), allowing for quantitative assessment of the analgesia/nociception balance in anesthetized patients. Ketamine, an analgesic adjuvant with sympathomimetic properties, has been shown to improve perioperative pain management. The purpose of this pilot study was to evaluate whether low-dose ketamine, due to its intrinsic effect on the sino-atrial node, affects HRV and, therefore, interferes with ANI measurements. This pilot study included 20 women undergoing abdominal hysterectomies. Anesthesia and analgesia were maintained with sevoflurane and fentanyl respectively, in a standardized manner. Five minutes after intubation, 0.5 μg kg(-1) of intravenous (i.v.) ketamine was administered. ANI, bispectral index (BIS), heart rate and blood pressure were recorded from the induction of anesthesia until 5 min after skin incision. There was not any significant decrease in mean (±SD) ANI values after intubation (2.11±20.11, p=0.35) or i.v. ketamine administration (1.31±15.26, p=0.28). The mean (±SD) reduction in ANI values after skin incision was statistically significant (13.65±15.44, p=0.01), which is consistent with increased nociception. A single i.v. bolus of 0.5 μg kg(-1) ketamine did not influence the ANI values of 20 women under standardized general anesthesia conditions and absent noxious stimulation. These results suggest that the ANI derived from the PhysioDoloris™ analgesia monitor is feasible under such clinical conditions.

Pre-emptive analgesia : effect of low dose Ketamine as pre-emptive analgesia in postoperative pain management after lower abdominal surgery

A Prospective randomized placebo-controlled study was done at Dhaka Medical College Hospital to evaluate the effects of low dose Ketamine as preemptive analgesia in post operative pain management after lower abdominal surgery. Sixty patients scheduled for elective total abdominal hysterectomy under General Anaesthesia were randomly divided into three equal groups. In Group-A, patients received 0.5 mg/kg ketamine I/V 90 seconds before incision, in Group-B, patients received the same dose after incision and in Group-C, patients were regarded as controlled, received 0.5 ml distilled water before incision. The patients were premedicated orally by giving Tab. diazepam 5mg with sips of water one hour before induction of anaesthesia. General anaesthesia was induced with thiopental sodium 3-5 mg/kg. Suxamethonium 1.5 mg/kg was given to facilitate endotracheal intubation. The neuromuscular block was continued with vecuronium. Anaesthesia was maintained with N20 (60-70%) and halothane in 02. Halothane was adjusted to maintain the MAP and heart rate within 20% of the pre-induction value. Opioids were not administered during the induction or during the operation. At the end of the anaesthesia, residual neuromuscular block was antagonized with intravenous neostigonine 0.05 mg/kg in atropine 0.02 mg/kg. In the post operative ward following parameters were recorded for 24 hours: recovery status, time of first analgesic demand, pain intensity by VAS &amp; VRS, total opioid consumption, sedation score, haemodynamic status and, complications like nausea, vomiting, delirium and hallucination. Upon the first complaint of moderate pain (&gt;5 on VAS), pethidine 1.5 mg/kg was administered intramuscularly &amp; then repeated 4 hourly. If pain intensity remained &gt;5 on VAS scale, rescue analgesic Pethidine 10 mg was administered intravenously. Time of first demand for analgesic among three groups: Gr- A( preincision): 68.4 ± 6 min; Gr-B (post-incision): 37.4 ± 3.3 min; and Gr-C (Control): 18.9 ± 2.1 min. It is statistically significant (P&lt;0.00) i, e, delayed in Gr. A. Total opioid consumption in 24 hours was: Gr. A: 8.6 ± 0.11 mg/kg, Gr. B: 9.0 ± 0.11 mg/kg and in Gr. C: 9.9 ± 0.14 mg/kg. (P&lt;0.00) i.e. less in Gr. A. The incidence of hallucination and delirium were present in Gr. A &amp; Gr. B but more in Gr. B than Gr. A. Nausea and vomiting were present in three groups. So, it can be concluded that preemptive use of ketamine significantly reduces postoperative pain and spare opioid consumption in the postoperative pain management. Journal of BSA, Vol. 17, No. 1 &amp; 2, 2004 p.17-22DOI: http://dx.doi.org/10.3329/jbsa.v17i1.4046

Interaction between postoperative shivering and hyperalgesia caused by high-dose remifentanil

BackgroundHigh-dose remifentanil-based anesthesia is associated with opioid-induced hyperalgesia (OIH) and postanesthetic shivering (PAS). These effects can be prevented by N-methyl-d-aspartate (NMDA) receptor antagonists. This study aimed to investigate correlations between OIH and PAS caused by high-dose remifentanil and the effects of low-dose ketamine on OIH and PAS.MethodsSeventy-five patients scheduled for single-port laparoscopic gynecologic surgery were randomly allocated into three groups, each of which received intraoperative remifentanil: group L at 0.1 µg/kg/min; group H at 0.3 µg/kg/min; and group HK at 0.3 µg/kg/min plus 0.25 mg/kg ketamine just before incision, followed by a continuous infusion of 5 µg/kg/min ketamine until skin closure.ResultsPAS, postoperative tactile pain threshold, and the extent of hyperalgesia in group H were significantly different (P < 0.05) than in the other two groups. PAS was significantly correlated with OIH, including mechanically evoked pain such as postoperative tactile pain threshold (r = -0.529, P = 0.01) (r = -0.458, P = 0.021) and the extent of hyperalgesia (r = 0.537, P = 0.002) (r = 0.384, P = 0.031), respectively, in group H and group HK. Notably, both groups were treated with high-dose remifentanil. Tympanic membrane temperature, time to first postoperative analgesic requirement, postoperative pain scores, analgesic consumption, and cumulative patient-controlled analgesia volume containing morphine were comparable in all three groups.ConclusionsOIH, including the enhanced perception of pain, and PAS were both associated with high-dose remifentanil, were significantly correlated and were attenuated by a low dose of ketamine. This suggests that a common mechanism in part mediated through activation of the central glutamatergic system (e.g., NMDA receptors), underlies the two effects caused by high doses of remifentanil.

Comments on "The Effect of Low-dose Ketamine on Post-caesarean Delivery Analgesia after Spinal Anesthesia"

Received September 24, 2013. Accepted October 8, 2013. Correspondence to: Mohamed Amin Ghobadifar Department of Student Research Committee, Medicine School, Jahrom University of Medical Sciences, Motahari Avenue, Jahrom, Iran Tel: +98-917-1020-790, Fax: +98-711-635-40-94, E-mail: amin_m505@yahoo.com This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright c The Korean Pain Society, 2014 LETTERS TO EDITORS

Effect of low-dose ketamine combined with propofol anesthesia on expression of GluR1 and GABAA R in hippocampus after electroconvulsive therapy in depressed rats

Objective To evaluate the effects of low-dose ketamine combined with propofol anesthesia on the expression of glutamate receptor 1 (GluR1) and γ-aminobutyric acid type A receptor (GABAA R) in hippocampus after electroconvulsive therapy (ECT) in depressed rats.Methods Fifty healthy adult male SpragueDawley rats,aged 2-3 months,weighing 200-250 g,were used in this study.The depressed model was induced by chronic unpredictable mild stress (CUMS).The mentally depressed rats were randomly divided into 5 groups (n =10 each):depression group (group D),ECT group,ketamine + ECT group (group KE),propofol + ECTgroup (group PE) and ketamine + propofol + ECT group (group KPE).Group ECT received ECT once a day for 7 consecutive days after intraperitoneal injection of normal saline 8 ml/kg.KE,PEK and KPE groups received ECT once a day for 7 consecutive days after intraperitoneal injection of ketamine 10 mg/kg,propofol 100 mg/kg,and ketamine 10 mg/kg + propofol 80 mg/kg,respectively.Sucrose fluid consumption was performed before CUMS,at 1 day after CUMS and at 1 day after ECT.The rats were sacrificed and hippocampi were removed for determination of the expression of GluR1 and GABAA R (by immuno-histochemistry).The GluR1/GABAA R ratio was calculated.Results Compared with group D,the sucrose consumption percentage was significantly increased at 1 day after ECT,the expression of GluR1 in hippocampal CA1 and CA3 regions was up-regulated,and the GluR1/GABAA Rratio was increased in the other four groups,and the expression of GABAA R in hippocampal CA1 and CA3 regions was down-regulated in ECT,PE and KPE groups (P ＜ 0.05).Compared with ECT group,the sucrose consumption percentage was significantly increased at 1 day after ECT,the expression of GABAA R and GluR1 in hippocampal CA1 and CA3 regions was up-regulated,and the GluR1/GABAA R ratio was increased in KPE group,the expression of GluR1 and GABAA R in hippocampal CA1 and CA3 regions was up-regulated in KE group,and the expression of GABAA R in hippocampal CA1 and CA3 regions was down-regulated in PE group (P ＜ 0.05).Compared with group PE,the sucrose consumption percentage was significantly increased at 1 day after ECT,the expression of GluR1 and GABAAR in hippocampal CA1 and CA3 regions was up-regulated,and the GluR1/GABAA R ratio was increased in KPE group (P ＜ 0.05).Conclusion The mechanism by which low-dose ketamine combined with propofol enhances the efficacy of ECT in depressed rats may be related to better regulation of the balance between hippocampal GluR1 and GABAA R. Key words: Depression; Ketamine ; Propofol ; Electroconvulsive therapy ; Receptors, AMPA ; Receptors, GABA-A; Hippocampus

The Effect of Low-dose Ketamine on Post-caesarean Delivery Analgesia after Spinal Anesthesia

BackgroundKetamine, an N-methyl-D-aspartate receptor antagonist, might play a role in postoperative analgesia, but its effect on postoperative pain after caesarean section varies with study design. We investigated whether the preemptive administration of low-dose intravenous ketamine decreases postoperative opioid requirement and postoperative pain in parturients receiving intravenous fentanyl with patient-controlled analgesia (PCA) following caesarean section.MethodsSpinal anesthesia was performed in 40 parturients scheduled for elective caesarean section. Patients in the ketamine group received a 0.5 mg/kg ketamine bolus intravenously followed by 0.25 mg/kg/h continuous infusion during the operation. The control group received the same volume of normal saline. Immediately after surgery, the patients were connected to a PCA device set to deliver 25-µg fentanyl as an intravenous bolus with a 15-min lockout interval and no continuous dose. Postoperative pain was assessed using the cumulative dose of fentanyl and visual analog scale (VAS) scores at 2, 6, 24, and 48 h postoperatively.ResultsSignificantly less fentanyl was used in the ketamine group 2 h after surgery (P = 0.033), but the difference was not significant at 6, 12, and 24 h postoperatively. No significant differences were observed between the VAS scores of the two groups at 2, 6, 12, and 24 h postoperatively.ConclusionsIntraoperative low-dose ketamine did not have a preemptive analgesic effect and was not effective as an adjuvant to decrease opioid requirement or postoperative pain score in parturients receiving intravenous PCA with fentanyl after caesarean section.

Opioid sparing effect of low dose ketamine in patients with intravenous patient-controlled analgesia using fentanyl after lumbar spinal fusion surgery

BackgroundThe opioid sparing effect of low dose ketamine is influenced by bolus dose, infusion rate, duration of infusion, and differences in the intensity of postoperative pain. In this study, we investigated the opioid sparing effect of low dose ketamine in patients with intravenous patient-controlled analgesia (PCA) using fentanyl after lumbar spinal fusion surgery, which can cause severe postoperative pain.MethodsSixty patients scheduled for elective lumbar spinal fusion surgery were randomly assigned to receive one of three study medications (K1 group: ketamine infusion of 1 µg/kg/min following bolus 0.5 mg/kg, K2 group: ketamine infusion of 2 µg/kg/min following bolus 0.5 mg/kg, Control group: saline infusion following bolus of saline). Continuous infusion of ketamine began before skin incision intraoperatively, and continued until 48 h postoperatively. For postoperative pain control, patients were administered fentanyl using IV-PCA (bolus dose 15 µg of fentanyl, lockout interval of 5 min, no basal infusion). For 48 h postoperatively, the total amount of fentanyl consumption, postoperative pain score, adverse effects and patients' satisfaction were evaluated.ResultsThe total amount of fentanyl consumption was significantly lower in the K2 group (474 µg) compared to the control group (826 µg) and the K1 group (756 µg) during the 48 h after surgery. Pain scores at rest or with movement, the incidence of adverse events and patient satisfaction were not significantly different among the groups.ConclusionsLow-dose ketamine at 2 µg/kg/min following bolus 0.5 mg/kg significantly reduced the total amount of fentanyl consumption during the 48 h after lumbar spinal fusion surgery without increasing adverse effects.

The effect of low dose ketamine and priming of cisatracurium on the intubating condition and onset time of cisatracurium

Chosun University Medical School/Chosun University Hospital, Department of Anaesthesiology and Pain Medicine, Gwangju, Korea, Republic of

The effect of low dose ketamine and priming of cisatracurium on the intubating condition and onset time of cisatracurium

BackgroundBoth ketamine and priming may accelerate the onset time of neuromuscular blocking agents. We investigate the effect of low dose ketamine and cisatracurium priming on the intubating condition and onset time of cisatracurium.MethodsAfter Institutional Review Board approval, 120 consecutive patients undergoing general anesthesia were randomly assigned to one of 4 groups. All patients were injected one of normal saline (group C), cisatracurium 0.01 mg/kg (group P), ketamine 0.5 mg/kg (group K) and combination of cisatracurium 0.01 mg/kg, and ketamine 0.5 mg/kg (group PK) diluted into a 5 ml solution, followed 3 minutes later by cisatracurium 0.15 mg/kg in group C and K, and 0.14 mg/kg cisatracurium in priming group. Onset time was recorded the electromyographical responses using single twitch and intubating conditions were evaluated at 60 seconds after cisatracurium administration.ResultsThe mean onset time was most significantly accelerated in Group PK and was also significantly more accelerated in Group P and K compared with Group C (P < 0.008). It was 112.7 ± 13.2, 91.4 ± 17.9, 84.9 ± 12.7 and 76.4 ± 8.3 seconds in Group C, P, K, and PK, respectively. Intubating conditions were significantly improved in Group P, K and PK than Group C (P < 0.008). Especially, Group PK showed most significant improvement of intubating conditions.ConclusionsThe combination of the low dose ketamine and cisatracurium priming accelerated the onset time and was improved the intubating conditions.

Effects of low dose ketamine combined with local anesthetic on postoperative complications after impacted third molar surgery

Aim: The aim of this study was to assess the clinical efficacy of local anesthetic combined with ketamine for the relief or prevention of postoperative pain, swelling, and trismus after the surgical extraction of impacted third molars.

Intra- and Postoperative Very Low Dose Intravenous Ketamine Infusion Does Not Increase Pain Relief after Major Spine Surgery in Patients with Preoperative Narcotic Analgesic Intake

This study aims to demonstrate the analgesic efficacy and opioid-sparing effect of low dose ketamine in patients with preoperative narcotic intake undergoing major spine surgery. The study used a prospective, randomized, double-blinded, and placebo-controlled clinical trial. We evaluated the analgesic efficacy and safety of low dose IV ketamine infusion after major spine surgery in patients with preoperative narcotic analgesic intake. Ketamine group received IV ketamine infusion (2 µg/kg/min) and saline group received saline intraoperatively and the first 24 hours postoperatively. In addition, all patients received IV patient-controlled hydromorphone and epidural bupivacaine. Pain scores, narcotic requirement, and side effects were compared between the groups for 48 hours postoperatively. Thirty patients completed the study (N = 15 in each group). No difference in pain scores at rest and movement was noted between the groups (P > 0.05). Patients in ketamine group received 40.42 ± 32.86 mg IV hydromorphone at 48 hours compared with 38.24 ± 26.19 mg in saline group (P = 0.84). Central nervous system side effects were observed in five (33%) ketamine group patients compared with nine (60%) in saline group (P = 0.29). The addition of IV very low dose ketamine infusion regimen did not improve postoperative analgesia. Side effects were not increased with low dose ketamine.