Patient-controlled analgesia following caesarean section under general anaesthesia: a comparison of fentanyl with morphine

The effect of age on clinical dose equivalency of fentanyl and morphine analgosedation in mechanically ventilated patients: Findings from the ANALGESIC trial

BACKGROUND

The dose equivalency of fentanyl vs. morphine is widely considered to be approximately 1:100. However, little is known about the effect of age on this ratio when these agents are used as infusions for analgosedation.

OBJECTIVES

To assess the impact of age on the clinical dose equivalency of fentanyl and morphine when used as infusions for analgosedation in mechanically ventilated intensive care unit patients.

METHODS

We performed a post hoc analysis of the Assessment of Opioid Administration to Lead to Analgesic Effects and Sedation in Intensive Care (ANALGESIC) cluster randomised crossover trial of fentanyl and morphine infusions for analgosedation. Dose and analgosedative clinical equivalency of fentanyl and morphine were assessed by age and by using different body-size descriptors.

RESULTS

We studied 663 patients (338 fentanyl, 325 morphine). Median (interquartile range) hourly dose of fentanyl and morphine were 58.1 (40.0-89.2) mcg and 3400 (2200-5000) mcg, respectively. The ratio of total dose of fentanyl:morphine was 1:93 in the 18- to 29-year-old group and 1:25 in the ≥80-year-old group (p = 0.015), respectively, with fentanyl becoming relatively less clinically effective as age increased. This effect was also seen when comparing dosing by different body-size descriptors with the strongest age-related change when using body surface area as body-size descriptor (p = 0.009).

CONCLUSION

The analgosedative clinical dose equivalency of fentanyl vs. morphine is heterogeneous when used as infusions for analgosedation, with fentanyl becoming relatively less clinically effective as age increases. This information can help guide prescription of these agents during transition from one agent to the other in critically ill patients.

Effects of opioids administered via intravenous or epidural patient-controlled analgesia after caesarean section: A network meta-analysis of randomised controlled trials

BACKGROUND

Post-caesarean section analgesia is important physiologically and psychologically for both mothers and infants. Patient-controlled analgesia is a well-established method of administering opioids for postoperative pain. However, to date, no study has systematically investigated the effects of opioids administered through intravenous patient-controlled analgesia (IVPCA) or patient-controlled epidural analgesia (PCEA) in parturients who have undergone caesarean section.

METHODS

This systematic review and network meta-analysis aimed to evaluate the analgesic and adverse effects of opioids administered via IVPCA or PCEA in parturients who have undergone a caesarean section. PubMed, Embase, Scopus, Web of Science, and Cochrane Library were searched from inception through 02 10, 2022 for relevant records. Randomised controlled trials (RCTs) that compared opioids administered via IVPCA or PCEA and reported outcomes of interest were included. Studies were excluded if the solution for patient-controlled analgesia contained antiemetics and/or other analgesics in addition to opioids. The methodological quality of RCTs was assessed using the revised Cochrane Risk of Bias Tool. Summary data were extracted from each eligible study. The primary outcome was pain intensity, and the secondary outcomes were opioid-related adverse effects. Frequentist network meta-analyses were performed using a contrast-based random-effects model. This study is registered with PROSPERO, CRD42021254040.

FINDINGS

Twenty-three studies with 2589 parturients were included. Compared with IVPCA morphine as a reference treatment, PCEA fentanyl had better analgesic effects at 4 h (mean difference [MD] in the visual analogue scale score, -0.75; 95% confidence interval [CI] [-1.16, -0.34]) and 8 h (MD, -0.93; 95% CI [-1.57, -0.28]) and yielded lower odds of developing nausea/vomiting (odds ratio [OR], 0.27; 95% CI [0.09, 0.80]) and sedation/drowsiness (OR, 0.22; 95% CI [0.11, 0.45]). However, PCEA fentanyl may be more likely to cause pruritus than IVPCA treatments.

INTERPRETATION

Considering the analgesic efficacy; opioid-induced nausea, vomiting, and sedation; and the well-being of breastfed infants, PCEA fentanyl may be the treatment of choice for post-caesarean section analgesia.

FUNDING

The Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation (TCRD-TPE-111-27).

Morphine versus fentanyl patient-controlled analgesia for postoperative pain control in major hepatic resection surgeries including living liver donors: A retrospective study

Background:

Liver resection surgery results in significant postoperative pain. However, it is still not clear which opioids used by patient-controlled analgesia (PCA) provides the best pain control and results in the least side effect in a patient with impaired liver function. Our hypothesis was that fentanyl is a better choice than morphine as it is a potent analgesic that its elimination half-life does not depend on the hepatic uptake and metabolism.

The Study Purpose:

Is to compare morphine and fentanyl PCA in liver resection patients as regards the degree of pain control, the consumption of opioids, and the side effects.

Methods:

A retrospective case–control study of hepatic resection patients who received postoperative morphine (Morph) or fentanyl (Fent) PCA. The study compared the pain scores, the morphine equivalent dose (MED), the number of demands requested as recorded by the PCA infusion pump, and the side effects every 12 h for 48 h.

Results:

This study yielded 40 patients; with the majority were living donor hepatic resection patients. There was no significant difference in the pain scores. However, the MED and the demands were significantly less in the Morph group. The P < 0.000, 0.0001, 0.0005, and 0.003, demands P < 0.002, 0.006, 0.014, and 0.013 at 12, 24, 48, and 36 h, respectively. The overall side effects were not different between the 2 groups at all time intervals measured; however, Morph patients were significantly more sedated in the first 12 h. There was one case of respiratory depression in the Morph group compared to two cases in the in the Fent group that needed treatment with naloxone.

Conclusions:

Although both groups had adequate pain control. The Morphine group reached faster pain control with less MED and PCA requests in liver resection patients, although it was more sedating in the first 12 h. However, fentanyl patients were less sedated; both drugs need close monitoring in the immediate postoperative period due to reported respiratory depressive effect and the need to use naloxone. The dosage of the PCA settings needs to be studied further to reach to the best dose with a reduced side effect. Further studies are recommended to reduce PCA dosages by introducing a multimodal approach of pain management relying on other methods with no additional sedative effects as regional anterior abdominal blocks.

Evaluation of the role of dexmedetomidine in improvement of the analgesic profile of thoracic paravertebral block in thoracic surgeries: A randomised prospective clinical trial

Background and Aims:

Thoracic paravertebral block (TPB) is one of the effective methods for management of post-operative pain in thoracic surgeries. The aim of the study was to evaluate effectiveness of addition of dexmedetomidine to paravertebral block with bupivacaine in improving the postoperative pain relief and pulmonary functions in patients undergoing thoracic surgeries.

Methods:

A prospective randomized double-blinded study was performed on forty patients scheduled for thoracic surgery. A paravertebral catheter was secured under ultrasound guidance preoperatively for all patients. Group B (n = 20) received a bolus dose of 0.25% bupivacaine at 0.3 mL/kg followed by continuous infusion of 0.125% bupivacaine 0.1 mL/kg/h. Group (BD) received a bolus dose of 0.25% bupivacaine + dexmedetomidine 1 μg/kg at 0.3 mL/kg followed by continuous infusion of dexmedetomidine 0.2 μg/kg/h + 0.125% bupivacaine 0.1 mL/kg/h. Anaesthesia technique was standardized for all patients. Postoperatively, all patients were assessed during first 24 hours for intraoperative fentanyl and post-operative morphine requirements, Visual Analogue Scores (VAS) scores at rest and during cough, and postoperative pulmonary functions.

Results:

Post-operative morphine consumption in the first 24 hours and intraoperative fentanyl requirement were significantly less in group BD (2.95 ± 1.986 mg, 80.75 ± 31.551μg respectively) compared to group B (9.85 ± 3.468 mg, 186 ± 39.683 μg respectively). Group BD showed less VAS scores during cough and better postoperative pulmonary functions (P < 0.05).

Conclusion:

Addition of dexmedetomidine to paravertebral bupivacaine in patients undergoing thoracic surgeries provides more effective analgesia with improvement in post-operative pulmonary functions.

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.

The efficacy of the time-scheduled decremental continuous infusion of fentanyl for postoperative patient-controlled analgesia after total intravenous anesthesia

BACKGROUND

Intravenous fentanyl has been used for acute postoperative pain management, but has not always provided reliable adequate analgesia, including patient-controlled analgesia (PCA). The purpose of this study was to investigate the efficacy of time-scheduled decremental infusion of fentanyl for postoperative analgesia.

METHODS

Ninety-nine patients, aged 20-65 years, undergoing laparoscopic-assisted hysterectomy using total intravenous anesthesia (TIVA) were randomly assigned into one of the three groups. Their background infusions of fentanyl diluent (2 ml/hr of diluent was equivalent with 0.5 µg/kg/hr of fentanyl) with PCA were maintained at the fixed-rate of 2 ml/hr until the postoperative 24 hr (FX2-2-2), or at the decremental rates of 6.0, 4.0, 2.0 ml/hr (D6-4-2) and 8.0, 4.0, 2.0 ml/hr (D8-4-2). The visual analogue score (VAS), incidence of inadequate analgesia, frequency of PCA intervention, and side effects were evaluated.

RESULTS

VAS was significantly higher in FX2-2-2 than in D6-4-2 and D8-4-2 until postoperative 3 hr (P < 0.05). After postoperative 4 hr, VAS was significantly higher in FX2-2-2 than D8-4-2 (P < 0.05). The incidence of inadequate analgesia of FX2-2-2 was significantly greater than D6-4-2 (P = 0.038) and D8-4-2 (P < 0.001) until postoperative 1 hr. None of the patients had ventilatory depression, and postoperative nausea and vomiting were not significant among the groups.

CONCLUSIONS

The time-scheduled decremental background infusion regimens of fentanyl, based on the pharmacokinetic model, could provide more effective postoperative pain management after TIVA, and the side effects and the risk for morbidity were not different from the fixed-rate infusion regimen.

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.

Nausea and vomiting after surgery under general anesthesia: an evidence-based review concerning risk assessment, prevention, and treatment

BACKGROUND

The German-language recommendations for the management of postoperative nausea and vomiting (PONV) have been revised by an expert committee. Major aspects of this revision are presented here in the form of an evidence-based review article.

METHODS

The literature was systematically reviewed with the goal of revising the existing recommendations. New evidence-based recommendations for the management of PONV were developed, approved by consensus, and graded according to the scheme of the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

The relevant risk factors for PONV include female sex, nonsmoker status, prior history of PONV, motion sickness, use of opioids during and after surgery, use of inhalational anesthetics and nitrous oxide, and the duration of anesthesia. PONV scoring systems provide a rough assessment of risk that can serve as the basis for a risk-adapted approach. Risk-adapted prophylaxis, however, has not been shown to provide any greater benefit than fixed (combination) prophylaxis, and PONV risk scores have inherent limitations; thus, fixed prophylaxis may be advantageous. Whichever of these two approaches to manage PONV is chosen, high-risk patients must be given multimodal prophylaxis, involving both the avoidance of known risk factors and the application of multiple validated and effective antiemetic interventions. PONV should be treated as soon as it arises, to minimize patient discomfort, the risk of medical complications, and the costs involved.

CONCLUSION

PONV lowers patient satisfaction but is treatable. The effective, evidence-based measures of preventing and treating it should be implemented in routine practice.

Postoperative intravenous patient-controlled analgesia in thyroid surgery: comparison of fentanyl and ondansetron regimens with and without the nonsteriodal anti-inflammatory drug ketorolac

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs), through synergistic action with opioids, can reduce postoperative nausea and vomiting via intravenous patient-controlled analgesia (PCA). We compared the efficacy of three PCA regimens.

METHODS

Patients (n = 135) undergoing thyroidectomy were randomly allocated to three PCA regimens. All groups received 12 mg ondansetron (a serotonin 5-HT(3) receptor antagonist). In addition, Group I received the opioid fentanyl, 15 microg/kg. Group II received fentanyl 12.5 microg/kg and the NSAID ketorolac, 1.5 mg/kg, and Group III received fentanyl 10 microg/kg and ketorolac 3 mg/kg. Pain scores, nausea and vomiting, and dizziness were assessed 1, 6, 12, and 24 hours postoperatively.

RESULTS

Pain scores were similar among the three groups. However, postoperative nausea and vomiting was significantly lower in groups II and III (p < 0.05) than group I. Postoperative dizziness was significantly lower in group III than groups I and II (p < 0.05).

CONCLUSIONS

The NSAID ketorolac when combined with lower doses of the opioid fentanyl and the same dose of ondansetron is associated with the same analgesic efficacy but less nausea and vomiting after thyroid surgery. A higher ratio of NSAID to opioid, when used as reported here, is associated with less postoperative dizziness.

Fentanyl HCl iontophoretic transdermal system versus intravenous morphine pump after gynecologic surgery

OBJECTIVE

To compare the efficacy and safety of fentanyl iontophoretic transdermal system (ITS) with morphine intravenous patient-controlled analgesia (IV PCA) for pain management following gynecologic surgery.

METHOD

A subgroup (n = 275) of gynecologic surgery patients from a randomized study (N = 636) of patients treated with fentanyl ITS or morphine IV PCA was analyzed. The main efficacy endpoint was the patient global assessment (PGA) of the method of pain control (first 24 h).

RESULT

In gynecologic surgery patients, PGA success ratings (excellent/good) were statistically equivalent (fentanyl ITS, 84.8%; morphine IV PCA, 83.9%; 95% confidence interval: -7.7%, 9.4%) based on the prespecified equivalence criterion of 10% for the entire study population. Pain intensity at 3 h (P = 0.296), discontinuations due to inadequate analgesia (P = 0.148), and percentages of patients requesting supplemental opioids in the first 3 h (P = 0.524) were similar.

CONCLUSION

The two modalities were therapeutically equivalent for pain management in these gynecologic surgery patients.

Patient-controlled analgesia

One of the most common methods for providing postoperative analgesia is via patient-controlled analgesia (PCA). Although the typical approach is to administer opioids via a programmable infusion pump, other drugs and other modes of administration are available. This article reviews the history and practice of many aspects of PCA and provides extensive guidelines for the practice of PCA-administered opioids. In addition, potential adverse effects and recommendations for their monitoring and treatment are reviewed.

An Iontophoretic Fentanyl Patient-Activated Analgesic Delivery System for Postoperative Pain: A Double-Blind, Placebo-Controlled Trial

An iontophoretic fentanyl HCl patient-activated transdermal system (fentanyl HCl PATS) is under development for the treatment of acute postoperative pain. The fentanyl HCl PATS is a needle-free, credit card-sized, preprogrammed system that is applied to the patient's upper outer arm or chest. The fentanyl HCl PATS was demonstrated to be superior to placebo in a previous trial; however, the randomization scheme used and the lack of control of entry pain level may have contributed to the lack of robust findings. We compared the fentanyl HCl PATS with placebo for acute postoperative pain management in a larger trial that addressed the limitations of the previous study. Adult patients admitted to the postanesthesia care unit after major surgery were titrated to comfort with opioids and randomized 1:1 to receive the fentanyl HCl PATS 40 microg or placebo for 24 hours. Supplemental IV fentanyl was available to patients upon request in both treatment groups for the first 3 hours after enrollment. The primary efficacy end-point was the percentage of patients who discontinued participation in the study because of inadequate analgesia. Pain intensity scores, patient global assessments (PGA), and investigator global assessments (IGA) were collected. Four-hundred-eighty-four patients (PATS, n = 244; placebo, n = 240) were enrolled. Fewer patients receiving the fentanyl HCl PATS discontinued because of inadequate analgesia compared with placebo (28.7% versus 60.0%; P < 0.0001). Mean last pain intensity scores were 3.5 and 5.4 for the fentanyl HCl PATS and placebo groups, respectively. Patients (73.4%, PGA) and investigators (72.1%, IGA) considered the fentanyl HCl PATS a good or excellent method of pain control. Treatment-related adverse events were similar between groups. This study demonstrated the superiority of the iontophoretic fentanyl HCl PATS over placebo for acute postoperative pain management.

Patient-controlled analgesia with fentanyl provides effective analgesia for second trimester labour: a randomized controlled study

PURPOSE

To examine dose and lockout intervals for effective fentanyl patient-controlled analgesia (PCA) in second trimester genetic termination of pregnancy, and compare three different fentanyl PCA regimes with morphine PCA.

METHODS

In a double-blind randomized study, 60 ASA physical status I-II patients received one of three fentanyl PCAs or morphine PCA. Labour was induced with prostaglandins and PCA use continued until delivery. Within two hours following delivery, four visual analogue scales (VAS) were administered measuring anticipated pain, pain relief in labour and delivery, and overall satisfaction. The drug delivery/demand ratio for two hours preceding delivery was obtained from the PCA pump. The outcome variables were analyzed using the Chi square test and analysis of variance as appropriate.

RESULTS

The delivery/demand ratio was 0.71 +/- 0.27 (mean +/- standard deviation) for morphine; 0.67 +/- 0.21 for fentanyl 50 micro g, lockout six-minute; 0.63 +/- 0.21 for fentanyl 25 micro g, lockout three-minute; and 0.81 +/- 0.17 for fentanyl 50 micro g, lockout three-minute groups. We found no significant differences among the four groups with respect to using delivery/demand ratio as a measure of pain relief. Morphine had the highest rate of side effects compared to fentanyl. There was strong evidence of differences among groups with regard to patient satisfaction and expected pain, and moderate evidence of differences in the delivery and labour pain scores.

CONCLUSION

This study found PCA fentanyl 50 micro g with a lockout period of six minutes provided satisfactory analgesia for second trimester labour.

The Safety and Efficacy of a Fentanyl Patient-Controlled Transdermal System for Acute Postoperative Analgesia: A Multicenter, Placebo-Controlled Trial

A noninvasive method of delivery of parenteral opioids for management of acute pain may offer logistic advantages for patients and nursing staff. A patient-controlled transdermal system (PCTS) under development consists of a preprogrammed, self-contained drug-delivery system that uses electrotransport technology (E-TRANS, ALZA Corp, Mountain View, CA) to deliver 40 micro g of fentanyl HCl over 10 min per on-demand dose for patient-controlled analgesia (PCA). In this randomized, double-blinded, placebo-controlled trial we compared the efficacy and safety of on-demand fentanyl HCl PCTS 40 microg against placebo for postoperative pain up to 24 h after major abdominal, orthopedic, or thoracic surgery in 205 patients. The primary efficacy measurement was the percentage of patients withdrawn from the study because of inadequate analgesia after completing at least 3 h of treatment. Secondary efficacy measures included mean pain intensity (using visual analog scales), patient global assessments, and investigator global assessments. Of 189 patients considered evaluable for efficacy, 25% of patients in the fentanyl HCl PCTS 40 microg group withdrew because of inadequate analgesia, compared with 40.4% of the placebo group (P < 0.05). Use of fentanyl HCl PCTS 40 micro g was associated with lower VAS scores and higher mean patient and investigator global assessment scores compared with placebo. No patient experienced clinically relevant respiratory depression. This study showed that a fentanyl HCl PCTS 40 microg for PCA was superior to placebo and well tolerated for the control of moderate to severe postoperative pain for up to 24 h after major surgery.

IMPLICATIONS

This multicenter, randomized, double-blinded, placebo-controlled trial showed that an on-demand fentanyl HCl patient-controlled transdermal system (PCTS) was superior to placebo and well tolerated for the control of moderate to severe postoperative pain for up to 24 h after major surgery. This fentanyl HCl PCTS is a preprogrammed, needle free, self-contained drug-delivery system that uses electrotransport technology (iontophoresis) to deliver 40 microg of fentanyl per on-demand dose.

Colostrum morphine concentrations during postcesarean intravenous patient-controlled analgesia

Patient-controlled analgesia (PCA) with morphine is a convenient method for providing postoperative analgesia. Despite the fact that it is used after cesarean delivery, data on transfer of morphine and of its active metabolite morphine-6 glucuronide (M6G) into maternal milk are scarce. It is not known whether breast-feeding during PCA with morphine has neonatal implications. We sought to measure morphine and M6G concentrations in colostrum during postpartum IV PCA and evaluate the potential for drug intake by neonates being breast-fed by these mothers. Seven informed and consenting mothers, given IV PCA with morphine, were investigated. Plasma and milk samples were obtained at titration, and at 12, 24, 36, and 48 h. Morphine and M6G were measured by high-performance liquid chromatography. In plasma, morphine concentrations ranged from <1 to 274 ng/mL, M6G ranged from <5 to 974 ng/mL. In milk, opioids were found in only 3 patients in whom morphine concentrations ranged from <1 to 48 ng/mL and M6G from <5 to 1084 ng/mL. The milk-to-plasma ratio was always <1 for morphine. In conclusion, we observed very small morphine and M6G concentrations in colostrum during PCA with morphine. Under these conditions, the amounts of drug likely to be transferred to the breast-fed neonate are negligible.

IMPLICATIONS

Colostrum concentrations of morphine and its active metabolite morphine-6 glucuronide were measured in mothers receiving patient-controlled analgesia with morphine after cesarean delivery. The concentrations were found to be very small, thus supporting the safety of breast-feeding in mothers receiving IV patient-controlled analgesia with morphine.

Anesthetic implications of the grey platelet syndrome

PURPOSE

To describe the obstetrical anesthetic care provided to two sisters with a rare qualitative platelet disorder, the grey platelet syndrome (GPS).

CLINICAL FEATURES

Both patients manifested thrombocytopenia prior to delivery without previous history of a bleeding diathesis or other abnormal laboratory tests of coagulation function. The first required emergency Cesarean section due to fetal bradycardia. Due to the thrombocytopenia and the emergency nature of the procedure, general anesthesia was used. During the C-section, 1.5-2 litres of old blood was noted in the abdominal cavity which was attributed to an old splenic capsular tear of unknown etiology. Work-up for the thrombocytopenia revealed large platelets on the peripheral smear with abnormal aggregation on platelet function studies. Electron microscopy of the platelets revealed absent alpha granules, diagnostic of GPS. The second patient, the sister of patient #1, presented in a similar fashion. However, at presentation, the platelet count was 112,000 x m(-3) and spinal anesthesia was provided without complication for Cesarean delivery. The same patient presented for a second delivery during which fetal bradycardia necessitated emergency C-section under general anesthesia. Despite administration of six units of platelets, blood loss was 5,200 mL. Her postpartum course was uncomplicated and she and the infant were discharged home on postoperative day #4.

CONCLUSION

The primary concerns for the anesthesiologist looking after patients with qualitative platelet defects are related to defective coagulation which influences the need for perioperative replacement of blood products and limits the use of regional anesthesia.

Continuous epidural analgesia with bupivacaine-fentanyl versus patient-controlled analgesia with i.v. morphine for postoperative pain relief after knee ligament surgery

BACKGROUND

Both epidural analgesia and intravenous patient-controlled analgesia (PCA) have been found efficacious after various types of surgery. We compared the efficacy, safety, side effects and patient satisfaction of these methods in a randomized double-blind fashion after elective anterior cruciate ligament reconstruction of the knee.

METHODS

Fifty-six patients had an epidural catheter placed at the L2-L3 interspace. Spinal anaesthesia with 15 mg of plain bupivacaine 5 mg/ml was performed at the L3-L4 interspace. After surgery the patients were randomly divided into three groups: 19 received a continuous epidural infusion with bupivacaine 1 mg/ml and fentanyl 10 mg/ml (F10), 19 patients received bupivacaine 1 mg/ml and fentanyl 5 microg/ml (F5) and 18 patients received saline (S). The rate of the epidural infusions was 0.1 ml kg(-1) h(-1). Each patient could also use an intravenous (i.v.) PCA device with 40 microg/kg bolus doses of morphine with a lockout period of 10 min and a maximum dose 240 microg kg(-1) h(-1). At the end of surgery ketoprofen 100 mg i.v. was given and continued orally three times a day. Patients were assessed for pain with a visual analogue scale (VAS) at rest and during activity, side effects and satisfaction at 3, 9 and 20 h.

RESULTS

Both epidural infusions (F10, F5) provided better analgesia than epidural saline plus i.v. PCA (S) (P<0.05). There was slightly less nausea in the S group (NS). In spite of the difference in the quality of pain relief, there was no difference between the groups in patient satisfaction regarding analgesic therapy.

CONCLUSION

Epidural infusion of fentanyl (1 microg kg(-1) h(-1) or 0.5 microg kg(-1) h(-1)) and bupivacaine (0.1 mg kg(-1) h(-1)) provided better pain relief but more side effects than intravenous morphine patient-controlled analgesia after knee ligament surgery. Almost all patients in all groups were satisfied with their pain relief.

The development of a maternal satisfaction scale for caesarean section

Satisfaction has become an important outcome measure. The purpose of this study was to develop a valid, reliable maternal satisfaction scale for women undergoing caesarean section. After Research Ethics Board approval, each patient gave verbal consent. To ensure face validity, patients were interviewed before and after caesarean section. Interviewing until no new items were generated ensured content validity. A draft scale using a 7 point Likert scale was given to 115 patients. Items endorsed by less than 15% of patients were deleted. Item-total correlations, principal component and factor analysis were performed and items in factors with less than three items or complex loadings excluded. Correlating the new scale to a Visual Analogue Scale (VAS) for satisfaction assessed construct validity. Reliability, as measured by internal consistency, was tested using Cronbach's alpha. Twenty-five women were interviewed for item generation. Patients were both nulliparous and multiparous and all received regional anaesthesia for elective or non-emergent caesarean section. Six items of the 33 on the draft scale were excluded because of lack of endorsement. Five items were excluded after principal component and factor analysis and two after item-total correlations. The correlation between the scale total and the VAS was 0.48. Cronbach's alpha was 0.82 for the total scale. Maternal sense of control was the item most related to satisfaction. This scale provides more detailed information than a simple VAS. In the population studied, this tool was found to be a valid and reliable method for assessing maternal satisfaction in women undergoing non-emergent caesarean section.

Neonatal effects of patient-controlled analgesia using fentanyl in labor

Patient-controlled analgesia (PCA) has been used at our institution for the past 5 years, as an alternative labor analgesic when epidural analgesia is contraindicated. This retrospective study evaluates the effects of maternal PCA fentanyl on infants of greater than 32 weeks gestational age. The neonatal charts (n=32) were reviewed for birth weight, gestational age, 1 min and 5 min Apgar scores, use of naloxone and umbilical venous gases. Infants requiring naloxone were defined as narcotized. Results from narcotized and non-narcotized neonates were compared with the Wilcoxon two-sample test. Fourteen infants had a 1 min Apgar score <or= 6. At 5 min the Apgar scores were all >or= 7, except in the three infants who had received naloxone. Gestational age, birth weight, method of delivery, PCA duration, time from last dose to delivery, total fentanyl used and rate of fentanyl infusion were not predictive of low 1 min Apgar scores. Three infants with a 1 min Apgar of 4 required naloxone. The total fentanyl received by mothers of infants who required naloxone was significantly higher than the group of mothers whose infants did not require naloxone (770 +/- 233 microg vs 298 +/- 287 microg, P = 0.027) Use of PCA fentanyl in this high-risk obstetric population was associated with a 44% incidence of moderately depressed neonates with an Apgar score <or= 6 at 1 min. Prospective controlled trials are needed to determine optimum PCA parameters in labor.

Antinociceptive effects of morphine and U-50,488H on vaginal distension in the anesthetized rat

The antinociceptive activity of the kappa- and mu-opioid receptor agonists, (+/-)-U-50,488H and morphine, was examined in a vaginal distension model in anaesthetized female rats. Vaginal distension induced a reproducible cardiovascular response (CVR) which was inhibited in a dose related manner by morphine (0.03-1.0 mg/kg i.v., ED50 = 0.16 mg/kg) and (+/-)-U-50,488H (0.08-1.6 mg/kg i.v., ED50 = 0.49 mg/kg). Morphine (0.3 microg/rat) administered i.c.v. inhibited the CVR by 81.6 +/- 7.9% whereas (+/-)-U-50,488H (30-300 microg/rat) was inactive by this route. A low dose of naloxone (30 microg/kg i.v.) blocked the effect of morphine but not that of (+/-)-U-50,488H. The kappa-opioid antagonist, nor-binaltorphimine (10 mg/kg s.c.) abolished the response to (+/-)-U-50,488H but not that of morphine. This demonstrates that both central and peripheral mu-opioid receptors may be involved in morphine-induced antinociception whereas the kappa-opioid agonist, (+/-)-U-50,488H, blocks vaginal nociception by acting on peripheral kappa-opioid receptors.