Epidural morphine prophylaxis of postoperative pain: report of a double-blind multicentre study

Analgesic Efficacy of Pfannenstiel Incision Infiltration with Ropivacaine 7.5 mg/mL for Caesarean Section

Background. Pain after Caesarean delivery is partly related to Pfannenstiel incision, which can be infiltrated with local anaesthetic solutions. Methods. A double- blind randomized control trial was designed to assess the analgesic efficacy of 7.5 mg/mL ropivacaine solution compared to control group, in two groups of one hundred and forty four parturients for each group, who underwent Caesarean section under spinal anaesthesia: group R (ropivacaine group) and group C (control group). All parturients also received spinal sufentanil (2.5 μg). Results. Ropivacaine infiltration in the Pfannenstiel incision for Caesarean delivery before wound closure leads to a reduction of 30% in the overall consumption of analgesics (348 550 mg for group R versus 504 426 mg for group C with P < .05), especially opioids in the first 24 hours, but also significantly increases the time interval until the first request for an analgesic (4 h 20 min ± 2 h 26 for group R versus 2 h 42 ± 1 h 30 for group C). The P values for the two groups were: P < .0001 for paracetamol, P < .0001 for ketoprofen and P for nalbuphine which was the most significant. There is no significant difference in the threshold of VAS in the two series. Conclusion. This technique can contribute towards a programme of early rehabilitation in sectioned mothers, with earlier discharge from the post-labour suite.

Analgesic efficacy and adverse effects of epidural morphine compared to parenteral opioids after elective caesarean section: a systematic review

BACKGROUND

The optimal effective dose of epidural morphine that provides postoperative analgesia after caesarean section with minimal side effects remains debated.

AIMS

We performed a systematic review to assess the analgesic efficacy and the incidence of adverse effects of epidural morphine after caesarean section compared to systemic analgesia with opioids.

METHODS

We searched Medline, Embase and Cochrane Collaboration Library databases. Studies were evaluated with the Modified Oxford Scale. Prospective randomized studies comparing analgesic efficacy and/or adverse effects of a single epidural morphine administration versus systemic opioids after elective caesarean section were included.

RESULTS

Ten studies (n=431) were selected. Epidural morphine increases the time until the first request for a rescue analgesic (Emax, 29.7 h; 95% confidence interval, 25.2-33.9) and decreases pain scores and postoperative morphine request during the first 24 h compared to systemic opioid analgesia. However, epidural morphine increases the incidence of pruritus (relative risk, 2.7; 95% CI, 2.1-3.6) and nausea (relative risk, 2.0; 95% CI, 1.2-3.3).

CONCLUSIONS

A single bolus of epidural morphine provides better analgesia than parenteral opioids but with an effect limited to the first postoperative day after caesarean section and with an increase in morphine side effects.

Pain relief and safety after major surgery. A prospective study of epidural and intravenous analgesia in 2696 patients

BACKGROUND

Adverse effects may still limit the use of continuous epidural and intravenous analgesia in surgical wards. This study postulated that postoperative epidural analgesia was more efficient, and had fewer side-effects than intravenous morphine. The aim was to investigate efficacy, adverse effects and safety of the treatments in a large patient population.

METHODS

During a five-year period 2696 patients undergoing major surgery, received either epidural or intravenous analgesia for postoperative pain relief. The patients were prospectively monitored in surgical wards. Pain was evaluated with a numeric rating scale (0-10) at rest/mobilization. Treatment duration, respiratory depression, sedation/hallucinations/nightmares/confusion, nausea/vomiting, pruritus, orthostatism/leg weakness, and insufficient pain relief were registered. Pain relief for all patients aimed at a pain scoring of less than 4 at rest.

RESULTS

Epidural analgesia was used in 1670 patients, and intravenous morphine in 1026 patients. Patients with epidural analgesia experienced less pain both at rest and during mobilization. Insufficient treatment effects such as dose adjustments, orthostatism/leg weakness, and pruritus were more common in the epidural group. Respiratory depression and sedation/hallucinations/nightmares/confusion occurred more often in the intravenous group. Thoracic epidural catheters caused a lower incidence of motor blockade compared to lumbar catheter placements.

CONCLUSION

In a large patient population the use of epidural and intravenous postoperative analgesia was considered safe in surgical wards, and the incidence of adverse effects was low. Patients with epidural analgesia experienced overall less pain, while opioid related side-effects were more common with intravenous morphine analgesia.

Droperidol and the side effects of epidural morphine after cesarean section

Epidural morphine produces analgesia with a high incidence of side effects that include pruritus, nausea, and vomiting. This study investigated whether epidural or i.v. droperidol could alleviate these symptoms. In a prospective, double-blind, randomized, controlled trial, 97 pregnant women undergoing cesarean section were randomly assigned to three groups. All received standard continuous epidural anesthesia. After delivery, each received 5 mg of epidural morphine with either no droperidol injection, 2.5 mg of epidural droperidol, or 2.5 mg of i.v. droperidol. The incidence, onset, duration, and severity of pruritus; the onset and severity of pain; and satisfaction were similar for each group, but the incidence and severity of nausea and vomiting was lower in the group that received i.v. droperidol (P < 0.01). Sedation was minimal throughout the study. Thus, epidural droperidol failed to alleviate the side effects caused by epidural morphine, but i.v.droperidol reduced both the incidence and severity of nausea and vomiting. These results suggest that droperidol acts systemically to counter the effects of epidural morphine but that it is not entirely effective.

IMPLICATIONS

A single dose of epidural morphine provides long-lasting pain relief for women who have undergone cesarean section, but it has some troublesome side effects (itching, nausea, vomiting). We performed a prospective, randomized, controlled trial in 97 such women to study whether droperidol could reduce these side effects. We found that i.v. droperidol reduced nausea and vomiting but did not prevent itching, and that epidural droperidol failed to prevent all side effects.

Local and regional anesthesia and analgesia

Many benefits can be obtained from the use of drugs applied locally or regionally when treating dogs and cats that are in pain or will be in pain because of surgical trauma. These techniques often use less medication than for systemic administration with a reduction in the likelihood of toxic effects from these compounds. Complete relief of pain can be achieved by blocking nerves originating from the site of injury by using local anesthetics, but this may entail loss of all sensation and motor paralysis. Other drugs, such as the opioids, may decrease the nociceptive input with minimal effect on motor activity. This report discusses the use of local anesthetics and other drugs for analgesia of the skin, mucous membranes, joints, pleura, and peritoneum, and the application of these drugs for regional blocks of peripheral nerves and epidural/intrathecal injection.

Intra-operative epidural morphine, fentanyl, and droperidol for control of pain after spinal surgery. A prospective, randomized, placebo-controlled, and double-blind trial

The present study was conducted to investigate the analgesic effects of intra-operatively administered epidural morphine in patients undergoing surgery for lumbar disc disease. Three treatment groups were constituted: one with 5.0 mg morphine and 2.5 mg dehydrobenzperidol (DHB) in 10 ml physiological saline, one with 5.0 mg morphine and 0.1 mg fentanyl in the same amount of saline, and one placebo group with saline only. The test solution was injected epidurally via catheter after haemostasis and before closure of the wound. Sixty eight patients were randomly assigned to each of the three groups and subjected to a double-blind evaluation. In the morphine/fentanyl and morphine/droperidol groups, significantly better analgesia was found as compared to the placebo group. No significant difference was found between the morphine/fentanyl and morphine/droperidol groups considering side effects of therapy, as well as duration and quality of analgesia. The side effects in the treatment groups were only slight and not significantly different from the placebo group. It was shown that additional epidural fentanyl offers no significant improvement of postoperative analgesia. No significant reduction of adverse effects could be found in the morphine/droperidol group compared to the morphine/fentanyl group. In conclusion, the intra-operative epidural application of morphine is a safe, effective and simple method for achieving sufficient analgesia in the first 24 hours after lumbar spinal surgery for disc disease.

Epidural analgesia with 4 mg of morphine after caesarean section: modulating effect of epidural block compared to general anaesthesia

Forty patients had epidural catheters placed for analgesia in active labour. For caesarean section patients in the epidural (EA) group (n = 20) had epidural anaesthesia with 0.5% bupivacaine supplemented if necessary with 2% lidocaine with adrenaline. Patients in the general anaesthesia (GA) group (n = 20) had standardized general anaesthesia for surgery. In both groups 4 mg of morphine in 8 ml of 0.25% bupivacaine was given epidurally after delivery of the baby. During the first 3 h of the postoperative period, as long as the epidural block was effective, patients in the EA group experienced significantly less pain. At 6, 12 and 24 h pain estimations were equal in both groups. Patients in the EA group consumed significantly less pain medication during the first 24 h after surgery (P = 0.0002). Itching was less frequent in the GA group (P = 0.011). It is concluded that epidural administration of 4 mg of morphine produces more effective postoperative pain relief when emergency caesarean section is conducted under epidural than when it is conducted under general anaesthesia.

Epidural morphine with butorphanol in pediatric patients

STUDY OBJECTIVE

To determine whether the addition of butorphanol to epidural morphine is effective in reducing the frequency of side effects caused by neuraxial opioids.

DESIGN

Randomized, double-blind study.

SETTING

Large tertiary care pediatric hospital.

PATIENTS

20 children between the ages of 2 and 17 years undergoing spinal, abdominal, or thoracic procedures.

INTERVENTIONS

Patients were divided randomly into one of two groups to receive either 80 micrograms/kg of preservative-free epidural morphine (Group 1) or 80 micrograms/kg of preservative-free epidural morphine with 40 micrograms/kg of butorphanol (Group 2).

MEASUREMENTS AND MAIN RESULTS

Blood pressure, heart rate, respiratory rate, and the first need for additional opioids were monitored in the two groups. In addition, pruritus, nausea and vomiting, and supplemental oxygen (O2) required to maintain oxygen saturation (SpO2) above 90% were monitored. Children who received butorphanol in addition to epidural morphine were much less likely to develop pruritus or nausea and vomiting or to require supplemental O2 to maintain SpO2 above 90%.

CONCLUSION

Butorphanol 40 micrograms/kg added to epidural morphine 80 micrograms/kg is effective in decreasing the occurrence of side effects caused by neuraxial opioids in pediatric patients.

A comparative study of patient-controlled epidural fentanyl and single dose epidural morphine for post-caesarean analgesia

In a prospective, randomized, double-blinded study, 23 patients who had undergone Caesarean delivery under epidural anaesthesia were assessed to evaluate the effectiveness of patient-controlled epidural analgesia (PCEA) with fentanyl compared with a single dose of epidural morphine for postoperative analgesia. Group A (n = 11) received epidural fentanyl 100 micrograms intraoperatively then self-administered a maximum of two epidural fentanyl boluses 50 micrograms (10 micrograms.ml-1) with a lockout period of five minutes for a maximum of two doses per hour. Group B (n = 11) received a single bolus of epidural morphine 3 mg (0.5 mg.ml-1) intraoperatively and received the same instructions as Group A but had their PCA devices filled with 0.9% NaCl. Patients were assessed up to 24 hr for pain, satisfaction with pain relief, nausea and pruritus using visual analogue scales (VAS). The treatments for inadequate analgesia, nausea and pruritus as well as time to first independent ambulation were recorded. The ventilatory response to carbon dioxide challenge was measured at four and eight hours. Pain relief, satisfaction with pain relief, and the use of supplemental analgesics were similar in both groups. The mean 24 hr dose of epidural fentanyl used by group A patients was 680 micrograms. Pruritus was less common in Group A patients at the 8 and 24 hr observation periods (P < 0.0125). Both groups experienced the same degree of nausea and clinically unimportant respiratory depression. We conclude that PCEA with fentanyl provides analgesia equal to a single dose of epidural morphine and may be suitable for patients who have experienced considerable pruritus after epidural morphine administration.

Complications related to thoracic epidural analgesia: a prospective study in 1071 surgical patients

In a prospective study, the complications of 1071 patients scheduled for thoracic epidural catheterization for postoperative analgesia (TEA) were studied. All catheters were inserted preoperatively between segment Th 2/3 and Th 11/12 under local anesthesia. Balanced anesthesia with endotracheal intubation and TEA were combined. Postoperatively 389 patients (36.9%) were monitored on a normal surgical ward. Buprenorphine, 0.15 to 0.3 mg, and if needed bupivacaine 0.375% 3-5 ml h-1 were given epidurally. Primary perforation of the dura occurred in 13 patients (1.23%). Radicular pain syndromes were observed in six patients (0.56%). In one patient (0.09%) respiratory depression was seen in close connection with the epidural administration of 0.3 mg buprenorphine. Although 116 patients (10.83%) showed one abnormal clotting parameter but no clinical signs of hemorrhage, there was no complication related to this group. No persisting neurological sequelae caused by the thoracic epidural catheters were found. In conclusion, continuous TEA with buprenorphine for postoperative pain relief after major abdominal surgery is a safe method without too high a risk of catheter-related or drug-induced complications, even on a normal surgical ward and when one clotting parameter is abnormal.

Epidural tramadol for postoperative pain relief

The efficacy of epidurally administered tramadol hydrochloride, a weak centrally acting analgesic, was studied for the relief of postoperative pain. Sixty patients undergoing abdominal surgery were randomly allocated to three treatment groups to be given the following agents by the epidural route: group 1 tramadol 50 mg; group 2 tramadol 100 mg; group 3 10 ml of bupivacaine 0.25%. The drugs were administered at the patients' request with each patient being allowed four doses in the first 24 h following surgery. Blood pressure, pulse rate, respiratory rate, arterial blood gas analyses, pain scores, the interval between doses and the occurrence of any side effects were recorded. Pain scores (assessed using a visual analogue scale) were significantly less (p < 0.05) at 3, 12, and 24 h in patients receiving tramadol 100 mg than in those receiving tramadol 50 mg or bupivacaine. The mean interval between doses for groups 1, 2 and 3 was 7.40 h, 9.36 h and 5.98 h respectively. The mean interval in group 2 was significantly longer than in group 3 (p < 0.05). The incidence of nausea and vomiting in group 2 was significantly higher than in group 3 (p < 0.05).

Epidural infusion of bupivacaine and diamorphine for postoperative analgesia. Use on general surgical wards

An audit of postoperative epidural analgesia in a District General Hospital is presented. Three hundred and forty-eight patients received epidural infusions of a bupivacaine and diamorphine mixture, and were managed on general surgical wards using a standard protocol of observations and instructions. Good analgesia was achieved in 339 (97%) patients. Respiratory depression, defined as a respiratory rate of eight breaths.min-1 or less, occurred in 22 (6%) patients, was of gradual onset, and was simply and successfully managed without morbidity. There were no respiratory arrests. Other complications, and the significance of catheter insertion level are discussed.

A comparison of epidural diamorphine with intramuscular papaveretum following caesarean section

Following caesarean section carried out under epidural blockade using local anaesthetic only, 40 consenting women were randomly allocated to receive either epidural diamorphine 2.5-5 mg in 10 ml physiological saline and intramuscular saline or epidural saline and intramuscular papaveretum 10-20 mg, dosage depending on weight, when the pain returned. When analgesia was next requested the alternative treatment was given. A visual analogue pain score was recorded before and 15, 30, 60, 120, 180 and 240 min after the first treatment. Respirations were counted and symptoms noted. On the following day the mother was asked whether she preferred the first or the second treatment. Both treatments produced a reduction in pain score but analgesia was significantly better with epidural diamorphine and the duration of action (8.5 +/- 5.2 h) was significantly longer than that following intramuscular papaveretum (4.1 +/- 2.3 h, P < 0.01). Two mothers who received epidural diamorphine initially required no further analgesia. No difference in respiratory rate was noted but side-effects were more frequent with epidural diamorphine. Despite this more women preferred this treatment. Because of enhanced mobility provided by good analgesia epidural diamorphine is worth offering to women following caesarean section.

Epidural morphine for analgesia after caesarean section: a report of 4880 patients

This retrospective study was undertaken to assess the efficacy and safety of epidural morphine in providing analgesia following Caesarean section under epidural anaesthesia. The morphine was administered as a single bolus, following delivery, in doses ranging from 2 to 5 mg. The charts of 4880 Caesarean sections, performed on 4500 patients, were reviewed. The duration of analgesia and the occurrence of any symptoms which might be side-effects of the epidural morphine were recorded. The duration of analgesia was 22.9 +/- 10.1 hr and was not correlated with the dose of epidural morphine. Eleven per cent of the patients required no supplemental analgesia during the first 48 hr. Twelve patients (0.25 per cent) had respiratory rates less than 10 breaths per minute, on at least one occasion. No serious sequelae resulted from these periods of bradypnoea. Pruritus occurred in 58 per cent of patients, nausea and vomiting in 39.9 per cent and dizziness in ten per cent. Herpes simplex labialis was recorded in 3.5 per cent of patients. Epidural morphine is thus confirmed as an effective analgesic technique post-Caesarean section with 3 mg being the optimal dose. Even in this young healthy patient population, clinically detectable respiratory depression occurs so clinical respiratory monitoring is indicated.

Spinal opioids: a nursing perspective

Nursing care of the patient receiving spinal opioids for pain control is reviewed in a comprehensive manner. Selection of patients, nursing management and patient outcomes are discussed. Three pain control techniques are described: epidural opioid injection for cancer pain, epidural opioid infusion for acute postoperative pain, and single dose spinal opioids for postcesarean section pain. Monitoring and pharmacologic aspects common to all three forms of spinal opioid treatment are given, and specific nursing interventions for each therapy are delineated.

The prevalence and impact of pain after day-care tubal ligation surgery

Empirical data from controlled studies using standardized, reliable measures on the amount and quality of pain after laparoscopic tubal ligation and the consequences of this pain on the activities of daily living are extremely scarce. In a study of 54 women admitted to a day-care unit for this procedure, validated measures were utilized to assess the incidence, intensity and duration of pain after tubal ligation (McGill Pain Questionnaire) and the impact of pain on the activities of daily living (Modified Functional Assessment Inventory). Psychological measures (Brief Symptom Inventory, Kranz Health Opinion Survey, and the State-Trait Anxiety Inventory) were employed to test their use as possible predictors for pain, analgesic usage and the time taken to resume a normal activity level after tubal ligation surgery. The results showed that pain is a significant problem after tubal ligation although pain rating scores over the 7-day study period were lower than those reported after major abdominal surgery. Eighty-five percent of our sample reported that pain and/or fatigue impacted on their recovery and contributed to an average delay of return to normal activity level of 4.4 days, not including the day of surgery. The psychological measures did not prove to be strong predictors of postoperative pain, time of return to normal activity level or analgesic usage. The most powerful predictor of return to normal activity was the total amount of pain experienced, as measured by the McGill Pain Questionnaire, during the 7 day post-operative period.

Epidural opioids in children

Experience with spinal opioids in children is limited but is expanding. Anatomy, pharmacology, technique, and results are reviewed. Complications and side effects are described.

Respiratory depression and spinal opioids

Administration of epidural and intrathecal opioids may provide excellent postoperative analgesia, but a minority of patients will suffer dangerous respiratory depression. This review discusses the detection and measurement of respiratory depression and summarizes the relevant literature as it pertains to epidural and intrathecal opioid administration. The respiratory depressant effects and pharmacokinetics of spinal opioids are reviewed. The clinical implications and areas of future investigation are discussed.

[Use of epidural and intrathecal opiates in obstetrics]

The discovery of opiate receptors and naturally occurring opiate-like substances in the central nervous system started a new era in pain control. Epidural and spinal opiates have been increasingly used since 1979. However, applying these analgesic techniques in obstetrics has been criticized because of possible side-effects on the mother and foetus. In this literature survey, their advantages and disadvantages are analyzed. Maternal side-effects include pruritus, nausea, urinary retention, and, most of all, respiratory depression. As a general rule, these side-effects are greater with the intrathecal route, high doses, and the use of morphine. The effects on the course of labour are small, and neonatal status is not altered. Spinal and epidural opiates are efficient analgesic techniques for labour and caesarean section. They provide a dose-related, but not surgical, analgesia. Currently, there is a great deal of interest in mixtures of a diluted local anaesthetic agent and a lipophilic drug for use during labour or caesarean section. An opiate alone may not consistently provide satisfactory analgesia during labour, and it cannot be recommended for routine use, except for patients in whom the cardiovascular effects of routine regional anaesthesia are to be avoided. The choice of a lipid-soluble opiate like fentanyl is safe. However, when considering new drugs, great care must be taken to avoid unforeseen problems. A good knowledge of the problem and a cautious approach combined with careful monitoring of the respiratory rate and adequacy of ventilation are the keys to the safe use of spinal and epidural opiates.

Naloxone infusion after prophylactic epidural morphine: effects on incidence of postoperative side-effects and quality of analgesia

There have been conflicting reports of the value of naloxone infusions to prevent the side-effects associated with epidural morphine. In our study, 29 patients undergoing thoracotomies for pulmonary surgery received epidural morphine (0.1 mg.kg-1) shortly after induction of anaesthesia. One hour after arrival in the Recovery Room, one of four naloxone bolus and infusion sequences was administered: saline bolus followed by saline infusion; 0.4 microgram.kg-1 naloxone bolus followed by 0.4 microgram.kg-1.hr-1 naloxone infusion; 2.0 micrograms.kg-1 naloxone bolus followed by 2.0 micrograms.kg-1.hr-1 naloxone infusion; and 4.0 micrograms.kg-1 naloxone bolus followed by 4.0 micrograms.kg-1.hr-1 naloxone infusion. Although with the number of patients studied, there were no statistically significant differences among groups, clinically, there was a trend toward decreased analgesia with all three naloxone infusion doses as determined by analgesic requirements, longest analgesic-free period and visual analogue pain scores. In addition, side-effects occurred in all groups. We conclude that prophylactic naloxone, used in this manner, is not an appropriate technique for the prevention of side-effects associated with epidural morphine used for the prevention of pain after thoracotomy.

Epidural and intrathecal opioids

Small doses of epidural and intrathecal opioids produce effective and prolonged analgesia postoperatively, although the quality of analgesia does not differ from when conventional routes are used. The different opioids differ only in the speed of onset and duration of action, and in the incidence of side-effects. 'Minor' complications such as nausea, vomiting, pruritus and retention of urine are relatively common. There is a small incidence of respiratory depression which is delayed for several hours after drug administration and which may be prolonged. It is commoner after morphine and after intrathecal administration, and is also associated with advanced age, concomitant use of other central depressant drugs, respiratory disease and large doses. Because of the potentially lethal nature of this complication, it is recommended that the epidural and intrathecal routes of administration are used only when patients can be closely and constantly observed postoperatively.