Low-dose intravenous ketamine improves postoperative analgesia after caesarean delivery with spinal bupivacaine in African parturients

Review of the Current Situation of Postoperative Pain and Causes of Inadequate Pain Management in Africa

Postoperative pain is one of the most prevalent complications following surgery, and more than 47% of surgical patients endure postoperative discomfort worldwide. In Africa, due to resource shortages and other issues, postoperative pain is substantially more common when compared to developed countries. Severe postoperative pain has many negative effects, including possibly death, which can burden both individuals and society as a whole. Therefore, effectively controlling postoperative pain is becoming increasingly important. To enhance the effectiveness of future pain management, a thorough analysis of the current reasons for inadequate postoperative pain management is necessary. In this article, the present situations of occurring postoperative pain, children's postoperative pain, and pain management in Africa are reviewed, based on relevant and recent literature. In particular, the reasons for inadequate postoperative pain management in Africa are detailed in this article from five perspectives: the inadequate assessment of postoperative pain, the knowledge gap among medical professionals, the patients' misconceptions, the scarcity of resources, and the lack of medications. Additionally, we offer appropriate solutions following various factors.

Effect of Intravenous Ketamine on Hypocranial Pressure Symptoms in Patients with Spinal Anesthetic Cesarean Sections: A Systematic Review and Meta-Analysis

Background: Pregnant women are more likely to suffer post-puncture symptoms such as headaches and nausea due to the outflow of cerebrospinal fluid after spinal anesthesia. Because ketamine has the effect of raising intracranial pressure, it may be able to improve the symptoms of perioperative hypocranial pressure and effectively prevent the occurrence of hypocranial pressure-related side effects. Method: Keywords such as ketamine, cesarean section, and spinal anesthesia were searched in databases including Medline, Embase, Web of Science, and Cochrane from 1976 to 2021. Thirteen randomized controlled trials were selected for the meta-analysis. Results: A total of 12 randomized trials involving 2099 participants fulfilled the inclusion criteria. There was no significant association between ketamine and the risk of headaches compared to the placebo (RR = 1.12; 95% CI: 0.53, 2.35; p = 0.77; I² = 62%). There was no significant association between ketamine and nausea compared to the placebo (RR = 0.66; 95% CI: 0.40, 1.09; p = 0.10; I² = 57%). No significant associations between ketamine or the placebo and vomiting were found (RR = 0.94; 95% CI: 0.53, 1.67; p = 0.83; I² = 72%). Conclusion: Intravenous ketamine does not improve the symptoms caused by low intracranial pressure after spinal anesthesia in patients undergoing cesarean section.

Effect of low-dose intravenous ketamine on postoperative pain following cesarean section under spinal anesthesia: A prospective cohort study, Ethiopia

Background

Following cesarean delivery, mothers experience moderate to severe pain since postoperative analgesia of spinal anesthesia is limited by duration of local anesthetic agents used. Analgesic effect of local anesthetic agents could be extended and supported by adding either intravenous or intrathecal adjuvants. The primary outcome of this study is to assess effect of low-dose intravenous ketamine on postoperative pain following cesarean section under spinal anesthesia.

Materials and methods

This prospective observational cohort study recruits 60 parturients who underwent elective cesarean delivery under spinal anesthesia. Those parturients who received intravenous ketamine 0.25 mg/kg following spinal anesthesia were considered as exposed group/ketamine group. The Non-exposed group was those parturients who didn't receive intravenous ketamine following spinal anesthesia. Numerical rating scale pain score, time to request first analgesia and total analgesia consumptions were recorded starting from 1st hour to 24 h after the end of surgery.

Results

The median and Inter quartile range (IQR) for postoperative numerical rating scale pain score was significantly higher in non-exposed group compered to ketamine group at 1st and 2nd hour after operation (P-value<0.05). Time to request first analgesia was significantly longer in ketamine group [192.5(140–210) minutes] compared to non-Exposed group [146(130–160) minutes] with P-value < 0.001. Tramadol consumption within 24 h postoperatively were significantly lower in ketamine group compared to non-exposed group (P-value < 0.001).

Conclusion

Low dose intravenous ketamine before skin incision was extended postoperative first analgesia request time by average of 45.5 min and decrease total analgesia consumption in 24 h.

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Ketamine group recorded significantly lower median pain NRS score at 1st and 2nd hour after operation.

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Total analgesic consumption within 24 h was less in ketamine group.

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First analgesia requestion time were longer in ketamine compared to non-exposed group postoperatively.

Comparison of haemodynamic changes between propofol and ketofol as induction agents in patients undergoing laparoscopic surgeries under general anaesthesia

Background and Aims:

Laparoscopic surgeries are more commonly performed procedure nowadays because of its advantages however generation of pneumoperitoneum causes significant physiological changes. Propofol is the most commonly used induction agent but its use is limited by its side effects like dose-dependent hypotension and myocardial depression. So by combining propofol with ketamine to form ketofol may result in better hemodynamic stability. The aim of this study was to compare the haemodynamic changes in patients undergoing laparoscopic surgery under general anesthesia using propofol and ketofol as induction agents.

Material and Methods:

In this prospective randomized double blind study, 80 patients of ASA I/II undergoing elective laparoscopic surgery were randomized into two Groups. Group A received 1 mg/kg of propofol + 1 mg/kg ketamine made up to a total volume of 20 ml with normal saline and Group B received 2 mg/kg propofol + normal saline to make up to an equal volume. Hemodynamic profiles like HR, SBP, DBP, and MAP were recorded at different time intervals until pneumoperitoneum. Postoperative recovery profile and complications were recorded. All data were entered in MS excel and analyzed using SPSS Version 20.0. Repeated measures ANOVA and Chi-square test were used to test the level of significance.

Results:

Demographic character and duration of surgery were comparable. SBP, DBP, MAP and HR showed statistically significant difference in both groups in various time intervals with P < 0.05 with Group A (ketofol ) having a better hemodynamic stability. Recovery profile in ketofol group took longer duration (4.95 min) compared to propofol group B (1.8 min). Postoperative nausea and vomiting were significant (P = 0.004) in ketofol group.

Conclusion:

We concluded that ketofol had a better hemodynamic stability compared to propofol as an induction agent, however time for recovery in ketofol group took a longer period compared to propofol group, with no complication in either groups.

Optimum dose of spinal ropivacaine with or without single intravenous bolus of S-ketamine during elective cesarean delivery: a randomized, double-blind, sequential dose-finding study

Background

Maternal hypotension after spinal anaesthesia occurs at a high rate during caesarean delivery and can lead to adverse maternal or foetal outcomes. The aim of this study was to determine the optimal dose of spinal ropivacaine for caesarean section with or without intravenous single bolus of S-ketamine and to observe the rates of hypotension associated with both methods.

Methods

Eighty women undergoing elective caesarean delivery were randomly allocated into either a ropivacaine only or ropivacaine with intravenous S-ketamine group. If the upper sensory level of the patient reached T6 and the visual analogue scale (VAS) scores remained below 3 points before delivery, the next patient had a 1/9th chance of receiving a lower dose or an 8/9th chance of receiving the same dose as the previous patient. If the patient had VAS scores of more than 2 points or needed an extra epidural rescue bolus before delivery, a higher dose was used for the next patient. The primary outcome was the successful use of spinal ropivacaine to maintain patient VAS score of < 3 points before delivery and the incidence of post-spinal hypotension in both groups. Secondary outcomes included the rates of hypotension-related symptoms and interventions, upper sensory level of anaesthesia, level of sedation, neonatal outcomes, Edinburgh Postnatal Depression Scale scores at admission and discharge, and post-operative analgesic effect. The 90% effective dose (ED90) and 95% confidence interval (95% CI) were estimated by isotonic regression.

Results

The estimated ED90 of ropivacaine was 11.8 mg (95% CI: 11.7–12.7) with and 14.7 mg (95% CI: 14.6–16.0) without intravenous S-ketamine, using biased coin up-down sequential dose-finding method. The rates of hypotension and associated symptoms were significantly lower in S-ketamine group than in the ropivacaine only group.

Conclusions

A spinal dose of ropivacaine 12 mg with a single intravenous 0.15 mg/kg bolus dose of S-ketamine may significantly reduce the risk of hypotension and induce sedation before delivery. This method may be used with appropriate caution for women undergoing elective caesarean delivery and at a high risk of hypotension or experiencing extreme nervousness.

Trial registration

http://www.chictr.org.cn (ChiCTR2000040375; 28/11/2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04229-y.

Analgesic effects of intravenous ketamine after spinal anaesthesia for non-elective caesarean delivery: a randomised controlled trial

OBJECTIVES

This study aimed to determine if low dose intravenous ketamine is effective in reducing opioid use and pain after non-elective caesarean delivery.

DESIGN

Prospective, randomised, double-blind.

SETTING

Tertiary hospital, Bisheshwar Prasad Koirala Institute of Health Sciences, Dharan, Nepal PARTICIPANTS: 80 patients undergoing non-elective caesarean section with spinal anaesthesia.

INTERVENTIONS

Patients were allocated in 1:1 ratio to receive either intravenous ketamine 0.25 mg/kg or normal saline before the skin incision.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the total amount of morphine equivalents needed up to postoperative 24 hours. Secondary outcome measures were postoperative pain scores, time to the first perception of pain, maternal adverse effects (nausea, vomiting, hypotension, shivering, diplopia, nystagmus, hallucination) and neonatal Apgar score at 1 and 5 min, neonatal respiratory depression and neonatal intensive-care referral.

RESULTS

The median (range) cumulative morphine consumption during the first 24 hours of surgery was 0 (0-4.67) mg in ketamine group and 1 (0-6) mg in saline group (p=0.003). The median (range) time to the first perception of pain was 6 (1-12) hours and 2 (0.5-6) hours in ketamine and saline group, respectively (p<0.001). A significant reduction in postoperative pain scores was observed only at 2 hours and 6 hours in the ketamine group compared with placebo group (p<0.05). Maternal adverse effects and neonatal outcomes were comparable between the two groups.

CONCLUSIONS

Intravenous administration of low dose ketamine before surgical incision significantly reduced the opioid requirement in the first 24 hours in patients undergoing non-elective caesarean delivery.

TRIAL REGISTRATION NUMBER

NCT03450499.

Strategies of analgesic treatment after cesarean delivery. Current state and new alternatives

The number of caesarean sections performed worldwide is increasing, and with it, the need for the optimal analgesia strategies. Deficient postoperative analgesia increases the need for opioids, delays recovery, and is associated with chronic pain and postpartum depression. It is essential to find good postoperative pain control strategies that facilitate early mobility, early recovery, and early hospital discharge with minimal side effects on the mother and infant. Multimodal analgesia based on neuroaxial anaesthesia with morphine in combination with non-opioids such as non-steroidal anti-inflammatory drugs and paracetamol, gives the best post-caesarean analgesia outcome, and allows anaesthesiologists to reserve opioids, corticoids, gabapentin, magnesium or ketamine for situations where neuroaxial anaesthesia cannot be performed, for high-risk patients, or when pain is difficult to control. Peripheral nerve block techniques can also be added, such as transverse abdominis plane block, erector spinae block, or continuous wound infiltration.

Systemic adjunct analgesics for cesarean delivery: a narrative review

It is critical to adequately treat postoperative cesarean delivery pain. The use of parenteral or neuraxial opioids has been a mainstay, but opioids have side effects that can be troubling and the opioid crisis in the United States has highlighted the necessity to utilize analgesics other than opioids. Other analgesic options include neuraxial analgesics, nerve blocks such as the transversus abdominis plane block, and non-opioid parenteral and oral medications. The goal of this article is to review non-opioid systemic analgesic adjuncts following cesarean delivery, focusing on their efficacy and side effects as well as their impact on reduction of opioid requirements after surgery.

Post-caesarean delivery analgesia in resource-limited settings: a narrative review

Post-caesarean pain is an important and often neglected outcome. It causes suffering, affects breastfeeding and is associated with postpartum depression and the development of chronic pain syndromes. Pain control is often difficult even in resource-rich environments; it is likely far worse in resource-limited settings, where emphasis is on reducing the high maternal mortality rate. Lack of adequate staffing, education, and postoperative monitoring severely limit the options in resource-limited settings. Resource-limited settings are further compromised by limited access to essential analgesic drugs and equipment for their administration. Solutions using affordable and accessible medications as part of a multimodal analgesic strategy are possible, supplemented by education and training programmes. More research is required, both to establish current practice and to test methods for improving maternal pain control. While government involvement is necessary to improve infrastructure and resources in individual countries, other solutions should also be sought, empowering local institutions and harnessing individual cultural characteristics.

Preemptive Analgesia Decreases Pain Following Anorectal Surgery: A Prospective, Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

Postoperative pain is a frequent cause for delayed discharge following outpatient procedures, including anorectal surgery. Both central and peripheral pain receptor sensitization are thought to contribute to postoperative pain. Blocking these receptors and preempting sensitization prevents hyperalgesia leading to lower pain medication requirements. Studies in the orthopedic, urologic, and gynecologic literature support this practice, but the use of preemptive analgesia in anorectal surgery is understudied.

OBJECTIVE

This study aimed to evaluate the effectiveness of preemptive analgesia in decreasing postoperative pain.

DESIGN

This is a randomized, double-blinded, placebo-controlled trial.

SETTING

This study was conducted at the University of Vermont Medical Center, a tertiary care referral center in Burlington, Vermont.

PATIENTS

Patients who were over 18 years of age, ASA Physical Status Classes I, II, or III, and undergoing surgery for anal fissure, fistula or condyloma or hemorrhoids were selected.

INTERVENTIONS

Preoperative oral acetaminophen and gabapentin followed by intravenous ketamine and dexamethasone were given before incision compared with oral placebos.

MAIN OUTCOME MEASURES

The primary outcomes measured were postoperative pain scores, percentage of patients utilizing breakthrough narcotics, and rates of side effects.

RESULTS

Ninety patients were enrolled. Because of patient withdrawal, screen failures, and loss to follow-up, 61 patients were analyzed (30 in the preemptive analgesia group and 31 in the control group). Patients in the active group had significantly less pain in the postanesthesia care unit and at 8 hours postoperatively. Significantly fewer participants in the active group used narcotics in the postanesthesia care unit and at 8 hours postoperatively. Average pain scores were excellent for both groups. There was no difference in the number of medication-related side effects between the 2 groups.

LIMITATIONS

This study was limited by the small sample size and excellent pain control in both groups.

CONCLUSIONS

Preemptive analgesia is safe and results in decreased pain in the early postoperative period following anorectal surgery. It should be implemented by surgeons performing these procedures. See Video Abstract at http://links.lww.com/DCR/A588.

Analgesic Effects of Preincision Ketamine on Postspinal Caesarean Delivery in Uganda's Tertiary Hospital: A Randomized Clinical Trial

Background. Good postoperative analgesic management improves maternal satisfaction and care of the neonate. Postoperative pain management is a challenge in Mulago Hospital, yet ketamine is accessible and has proven benefit. We determined ketamine's postoperative analgesic effects. Materials and Methods. We did an RCT among consenting parturients that were randomized to receive either intravenous ketamine (0.25 mg/kg) or placebo after spinal anesthetic. Pain was assessed every 30 mins up to 24 hours postoperatively using the numerical rating scale. The first complaint of pain requiring treatment was noted as “time to first breakthrough pain.” Results. We screened 100 patients and recruited 88 that were randomized into two arms of 44 patients that received either ketamine or placebo. Ketamine group had 30-minute longer time to first breakthrough pain and lower 24-hour pain scores. Postoperative diclofenac consumption was lesser in the ketamine group compared to placebo and Kaplan-Meier graphs showed a higher probability of experiencing breakthrough pain earlier in the placebo group. Conclusion. Preincision intravenous ketamine (0.25 mg/kg) offered 30-minute prolongation to postoperative analgesia requirement with reduced 24-hour pain scores. We recommend larger studies to explore this benefit. This trial is registered with Pan African Clinical Trial Registry number PACTR201404000807178.

Comparison of pregabalin versus ketamine in postoperative pain management in breast cancer surgery

Background:

Breast surgery compromises one of the most common cancer surgeries in females and commonly followed by acute postoperative pain. Pregabalin and ketamine have been used in many previous studies and was found to have a good analgesic profile. We assumed that pregabalin and ketamine can be used in control of postoperative pain in female patients undergoing breast cancer surgery.

Material and Methods:

Ninety female patients scheduled for cancer breast surgery were allocated in three groups (30 patients each), control group (group c) received preoperative placebo, pregabalin group (group p) received oral 150 mg pregabalin 1 h before surgery, ketamine group (group k) received intravenous (IV) 0.5 mg/kg ketamine with induction of anesthesia followed by 0.25 mg/kg/h IV throughout the surgery. All patients received general anesthesia and after recovery, the three groups were assessed in the first postoperative 24 h for postoperative visual analog scale (VAS), total 24 h morphine consumption, incidence of postoperative nausea and vomiting (PONV), sedation score >2 and any complications from the drugs used in the study.

Results:

The use of pregabalin or ketamine was found to reduce total postoperative morphine consumption with P < 0.001. There was no difference between pregabalin and ketamine groups in opioid requirement. There was no difference between the three groups in postoperative VAS scores or incidence of PONV and sedation score >2.

Conclusion:

The use of preoperative oral 150 mg pregabalin 1 h before surgery or IV 0.5 mg ketamine with induction of anesthesia can reduce postoperative opioid consumption in breast cancer surgery without change in sedation or PONV and with a good safety profile.

Intravenous ketamine during spinal and general anaesthesia for caesarean section: systematic review and meta-analysis

BACKGROUND

Intravenous ketamine has been used during general and regional anaesthesia for caesarean section. No systematic review and meta-analysis on the desired effects and adverse effects of ketamine administration during caesarean section have yet been performed.

METHODS

After a systematic literature search a meta-analysis was conducted with the random effects model. Weighted mean difference (WMD) or risk ratio and 95% confidence intervals (CIs) were computed.

RESULTS

Twelve randomised controlled double-blind trials comprising 953 patients were included: seven studies reported on spinal anaesthesia and five on general anaesthesia. Significant differences in the aforementioned outcome variables were found only in the spinal anaesthesia studies. In the spinal anaesthesia studies the time to the first analgesic request was significantly longer in ketamine-treated women, the WMD was 49.36 min (95% CI 43.31-55.41); visual analogue scale pain scores at rest 2 h after surgery were significantly lower. No differences were observed for maternal nausea, vomiting, pruritus, and psychomimetic effects. Only few data were found for neonatal outcomes.

CONCLUSIONS

We conclude that ketamine enhances post-operative analgesia after caesarean section under spinal anaesthesia. There is a paucity of data for several maternal adverse effects as well as for neonatal well-being. Further studies are needed for general anaesthesia.

The effect of low-dose intravenous ketamine on postoperative pain following cesarean section with spinal anesthesia: a randomized clinical trial

OBJECTIVES

Low-dose ketamine has been considered a good substitute for opioids for controlling postoperative pain. The purpose of this study was to determine the effect of low-dose intravenous ketamine following cesarean section with spinal anesthesia on postoperative pain and its potential complications.

METHODS

One hundred and sixty pregnant women volunteered to participate in this randomized controlled trial. Participants were randomly divided into two groups (n=80 for each group). Five minutes after delivery, the experimental group received 0.25mg/kg ketamine while the control group received the same amount of normal saline.

RESULTS

There was a significant difference between the two groups in the severity of pain at one, two, six, and 12 hours following surgery. Postoperative pain was significantly less severe in the experimental group. Compared to the control group, the experimental group felt pain less frequently and therefore asked for analgesics less often. On average, the number of doses of analgesics used for the participants in the experimental group was significantly less than the number of doses used for the control group. Analgesic side effects (including nausea, itching, and headache) were not significantly different between the two groups. However, vomiting was significantly more prevalent in the control group and hallucination was more common in the experimental group.

CONCLUSION

We conclude that administration of low doses of ketamine after spinal anesthesia reduces the need for analgesics and has fewer side effects than using opioids. Further studies are required to determine the proper dose of ketamine which offers maximum analgesic effect. Furthermore, administration of low-dose ketamine in combination with other medications in order to minimize its side effects warrants further investigation.

Does the Method and Timing of Intravenous Ketamine Administration Affect Postoperative Morphine Requirement After Major Abdominal Surgery?

OBJECTIVE

Single intravenous bolus administration and postoperative or perioperative infusions are the most preferred methods of ketamine. Nevertheless, there is no clear explanation on the ideal ketamine administration method. In this study, we aimed to compare the effects of the most common ketamine administration methods and administration time on postoperative opioid consumption.

METHODS

Fifty-two patients undergoing colectomy for colon cancer were randomly assigned into four groups. Group 1 was the control group. Group 2 received only a single intravenous bolus dose of 0.5 mg kg(-1) ketamine at induction. Group 3 received 0.5 mg kg(-1) intravenous ketamine bolus at induction and perioperative ketamine infusion at a rate of 0.25 mg kg(-1) h(-1). Group 4 received a bolus of 0.5 mg kg(-1) intravenous ketamine at induction and perioperative and postoperative ketamine infusion at a rate of 0.25 mg kg(-1) h(-1). Postoperatively, visual analogue scale pain scores, side effects, and morphine consumption were recorded.

RESULTS

There was no statistically significant difference in postoperative pain scores. Total morphine consumption was found to be significantly lower in Group 4 compared to the other groups (p=0.03, p=0.004, p=0.03, respectively). During the 1(st), 2(nd), and 4(th) hours in the postoperative period, patient-controlled analgesia morphine consumption was significantly lower in Group 4 compared to the control group (p<0.01).

CONCLUSION

Preoperative single-bolus dose or intraoperative low-dose ketamine infusion does not decrease postoperative morphine consumption; however, per- and postoperative 48-hour ketamine infusion has a significant effect in decreasing morphine consumption without decreasing the incidence of side effects in patients undergoing major abdominal surgery.

Preoperative low-dose ketamine has no preemptive analgesic effect in opioid-naïve patients undergoing colon surgery when nitrous oxide is used - a randomized study

BACKGROUND

The analgesic properties of ketamine are associated with its non-competitive antagonism of the N-methyl-D-aspartate receptor; these receptors exhibit an excitatory function on pain transmission and this binding seems to inhibit or reverse the central sensitization of pain. In the literature, the value of this anesthetic for preemptive analgesia in the control of postoperative pain is uncertain. The objective of this study was to ascertain whether preoperative low-dose ketamine reduces postoperative pain and morphine consumption in adults undergoing colon surgery.

METHODS

In a double-blind, randomized trial, 48 patients were studied. Patients in the ketamine group received 0.5 mg/kg intravenous ketamine before surgical incision, while the control group received normal saline. The postoperative analgesia was achieved with a continuous infusion of morphine at 0.015 mg∙kg-¹∙h-¹ with the possibility of 0.02 mg/kg bolus every 10 min. Pain was assessed using the Visual Analog Scale (VAS), morphine consumption, and hemodynamic parameters at 0, 1, 2, 4, 8, 12, 16, and 24 hours postoperatively. We quantified times to rescue analgesic (Paracetamol), adverse effects and patient satisfaction.

RESULTS

No significant differences were observed in VAS scores between groups (P>0.05), except at 4 hours postoperatively (P=0.040). There were no differences in cumulative consumption of morphine at any time point (P>0.05). We found no significant differences in incremental postoperative doses of morphine consumption in bolus, except at 12 h (P =0.013) and 24 h (P =0.002). The time to first required rescue analgesia was 70 ± 15.491 min in the ketamine group and 44 ± 19.494 min in the control (P>0.05). There were no differences in hemodynamic parameters or patient satisfaction (P>0.05).

CONCLUSIONS

Preoperative low-dose-ketamine did not show a preemptive analgesic effect or efficacy as an adjuvant for decreasing opioid requirements for postoperative pain in patients receiving intravenous analgesia with morphine after colon surgery.

Analgesic effect of low dose subcutaneous ketamine administration before and after cesarean section

BACKGROUND

Pain is considered as an importantissue after cesarean section. Multimodal approach to post cesarean pain management may not only enhance analgesia but also reduce side effects after the surgery.

OBJECTIVES

This study was aimed to evaluate the clinical efficacy of subcutaneous injection of low dose ketamine at the incision site to reduce cesarean section pain.

PATIENTS AND METHODS

Sixty patients, aged between 18 and 25 years old, scheduled for elective cesarean section, were enrolled to this double-blind randomized controlled trial study. Patients were divided into three groups of 20 patients each group one (k-pre) received 0.5 mg/kg ketamine before skin incision and normal saline after skin closure, group two (k-post) received normal saline before skin incision and 0.5 mg/kg ketamine after skin closure and group three (C) received normal saline before skin incision and after skin closure; subcutaneously at the incision site. The first analgesic request, the amount of analgesic and the pain intensity were evaluated for 24 hours.

RESULTS

The first time analgesic requested was longer and the amount of analgesic used during the first 24 hours was significantly lower in groups K-pre and K-post compared with group C (P < 0.05). Pain intensity was significantly lower at 2, 4, 6 and 12 hours in groups K-pre and K-post compared with group C (P < 0.05). Nevertheless, pain intensity was not significantly different at 18 and 24 hours in group C (P > 0.05). The first requested time, total used amount of analgesicand pain intensity were not meaningfully different in K-pre and K-post groups (P > 0.05).

CONCLUSIONS

Patients who were given ketamine before or after cesarean section subcutaneously at incision site had lower pain intensity and less analgesic consumption than patients who were given placebo.

Effects of the addition of low-dose ketamine to propofol-fentanyl anaesthesia during diagnostic gynaecological laparoscopy

OBJECTIVES

Diagnostic gynaecological laparoscopy (DGL) is a brief procedure, generally performed on an outpatient basis. Propofol-fentanyl is often used for anaesthesia in minor outpatient procedures because of its rapid onset, short duration of action and smooth patient awakening. However, propofol has various cardiovascular effects such as reduced arterial pressure, cardiac output and cardiac index. Ketamine is an intravenous anaesthetic and short-acting analgesic that could alleviate the haemodynamic effects of propofol due to its sympathomimetic activity. The aim of this placebo-controlled trial was to evaluate the effects of the addition of low-dose ketamine to propofol-fentanyl anaesthesia in DGL.

STUDY DESIGN

In this double-blind randomized trial, 60 healthy women undergoing gynaecological laparoscopy to investigate infertility were studied. Following injection of midazolam and fentanyl in all patients, the study group (n=30) received ketamine 0.5 mg/kg and propofol 1-2.5 mg/kg, and the placebo group (n=30) received saline 0.9% and propofol 1-2.5 mg/kg. Propofol was subsequently infused for the maintenance of anaesthesia.

RESULTS

Patients in the study group had a significantly lower incidence of pain than patients in the placebo group during propofol injection (13% vs 87%, respectively; p<0.0001). After induction of anaesthesia, 16 (53%) patients in the placebo group and three (10%) patients in the study group had a decreased heart rate (p<0.001). The decrease in mean arterial pressure was greater in the placebo group compared with the study group (37% vs 7%, respectively; p<0.001). During the procedure, the total mean±standard deviation dose of propofol was 420±65 mg in the placebo group and 330±35 mg in the study group (p<0.001). Pain scores for the first 3h after the operation were significantly lower in the study group (p<0.001).

CONCLUSION

Use of low-dose ketamine with propofol-fentanyl anaesthesia in patients undergoing DGL was associated with less pain during propofol injection, lower incidence of haemodynamic changes, lower total dose of propofol and improved postoperative analgesia.

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

Background

Ketamine, 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.

Methods

Spinal 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.

Results

Significantly 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.

Conclusions

Intraoperative 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.