Intravenous Fentanyl Patient-controlled Analgesia Research Articles

The efficacy of rhomboid intercostal block for pain management after video-assisted thoracoscopic surgery: a prospective, randomized-controlled trial.

We aimed to evaluate the efficacy of rhomboid intercostal block (RIB) for analgesia management in patients who underwent video-assisted thoracoscopic surgery. Adult patients who underwent VATS under general anesthesia between July 2020 and June 2022 were included in the study. There was two groups in this study: RIB (n = 25) vs control (n = 25) group. RIB was performed with 30 ml 0.25% bupivacaine at the end of the surgery. Surgical intercostal blockade was performed with 30 ml 0.25% bupivacaine in the control group. The patients received intravenous fentanyl patient-controlled postoperative analgesia. The numerical rating score (NRS), opioid consumption, and adverse events were recorded. A total of 50 patients were randomized into 2 groups. There were no significant difference in terms of the demographic data between groups (P > 0.05). Postoperative opioid consumption at 0-8, 8-16, 16-24, and 24-48 h and rescue analgesic use were significantly lower in RIB group (P < 0.05). At all times, the static/dynamic NRS were significantly lower in RIB group. The rate of nausea and itching was higher in control group (P < 0.05). US-guided RIB provides effective post-VATS analgesia.

Erector spinae plane block vs interscalene brachial plexus block for postoperative analgesia management in patients who underwent shoulder arthroscopy

BackgroundInterscalene brachial plexus block (ISB) is the gold standard method used for postoperative analgesia after arthroscopic shoulder surgery. Ultrasound guided erector spinae plane block (ESPB) is an interfascial plane block. The aim of this study is to compare the analgesic efficacy of ESPB and ISB after shoulder arthroscopy. The primary outcome is the comparison of the perioperative and postoperative opioid consumptions.MethodsSixty patients with ASA score I-II planned for arthroscopic shoulder surgery were included in the study. ESPB was planned in Group ESPB (n = 30), and ISB was planned in Group ISB (n = 30). Intravenous fentanyl patient-controlled analgesia was administered to both groups in the postoperative period. Intraoperative and postoperative opioid and analgesic consumption of both groups, side effects and complications related to opioid use, postoperative pain scores and rescue analgesic use were recorded in the first 48 h postoperatively.ResultsPain scores were significantly higher in the ESPB group in the first 4 h postoperatively than in the ISB group (p < 0.05). The total fentanyl consumption and number of patients using rescue analgesics in the postoperative period were significantly higher in the ESPB group (p < 0.05). The incidence of nausea in the postoperative period was significantly higher in the ESPB group (p < 0.05).ConclusionsIn our study, it was seen that ISB provided more effective analgesia management compared to ESPB in patients underwent shoulder arthroscopy surgery.

Predictive factors of postoperative fentanyl consumption in patients with inflammatory bowel disease: a retrospective cohort study

BackgroundPatients with inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, might present difficulties in achieving postoperative analgesia. Prior studies have suggested that patients with IBD undergoing major abdominal surgery require higher doses of perioperative opioids than do patients without IBD. Considering patients with IBD potentially require high-dose opioids, identifying those requiring higher opioid doses will allow clinicians to optimize the perioperative opioid dose and avoid insufficient pain management or complications of opioid overdose. Therefore, we conducted this study to identify predictive factors that might influence postoperative opioid consumption in patients with IBD.MethodsThis single-center, historical cohort study reviewed the medical records of all patients admitted to the IBD center of our institution for surgery and who used intravenous fentanyl patient-controlled analgesia (PCA) after open abdominal surgery between June 2013 and April 2017. Ultimately, 179 patients were enrolled in the analysis. Variables expected to influence and/or represent pain, analgesia, inflammation, disease condition, and extent of surgery were selected as potential explanatory variables for predicting postoperative opioid consumption. Multivariable linear regression analysis was used to examine the effect of independent variables on postoperative fentanyl consumption.ResultsOf the nine predictive variables selected using the stepwise-selection method, eight were significant. Intraoperative fentanyl consumption, current smoking, ulcerative colitis, administration of biologics during the month before surgery, and the use of supplementary analgesics had a significant increasing effect on postoperative fentanyl consumption, whereas droperidol concentration in the PCA solution, age, and diabetes mellitus had a significant decreasing effect. Preoperative use of opioids was a non-significant variable. The adjusted coefficient of determination was 0.302.ConclusionsIntraoperative fentanyl consumption, current smoking, ulcerative colitis, administration of biologics during the month before surgery, and the use of supplementary analgesics had a significant increasing effect, whereas droperidol concentration in the PCA solution, age, and diabetes mellitus had a significant decreasing effect on postoperative fentanyl consumption. These factors should be considered when adopting postoperative intravenous fentanyl PCA administration for patients with IBD.Trial registrationRegistry: UMIN Clinical Trials Registry.Clinical Trial Number: UMIN000031198.Date of registration: February 8, 2018.

Adding Dexmedetomidine to Bupivacaine in Ultrasound-guided Thoracic Paravertebral Block for Pain Management after Upper Abdominal Surgery: A Double-blind Randomized Controlled Trial.

BackgroundParavertebral blocks are one of the possible postoperative pain management modalities after laparotomy. Adjuvants to local anesthetics, including alpha agonists, have been shown to lead to better pain relief and increased duration of analgesia.ObjectivesThe aim of this study is to examine the effect of adding dexmedetomidine to bupivacaine for ultrasound-guided paravertebral blocks in laparotomy.MethodsIn this double-blind, randomized controlled trial (RCT), we enrolled 42 patients scheduled for T6 to T8 thoracic paravertebral block (TPVB) for analgesia after laparotomy. The patients were randomly assigned into two groups of BD (bupivacaine 2.5 mg/mL 20 mL plus dexmedetomidine 100 µg) and B (bupivacaine 20 mL alone). Following surgery, intravenous fentanyl patient-controlled analgesia was initiated. The numerical rating scale (NRS) for pain, sedation score, total analgesic consumption, time to first analgesic requirement, side effects (such as nausea and vomiting), respiratory depression, and patients’ satisfaction during the first 48 hours of evaluation were compared in the two groups.ResultsPain scores and mean total analgesic consumption at the first 48 hours in the BD group were significantly lower than Group B (P = 0.03 and P < 0.001, respectively). The time of first analgesic request was significantly longer in BD group (P < 0.001). Sedation scores and side effects did not differ significantly between the two groups.ConclusionsAdding dexmedetomidine to bupivacaine for TPVB after laparotomy yielded better postoperative pain management without significant complications.

Comparison of Analgesic Efficacy of Erector Spinae Plane Block and Posterior Quadratus Lumborum Block in Laparoscopic Liver Resection: A Randomized Controlled Trial.

PurposeUltrasound-guided fascial plane blocks, including the erector spinae plane (ESP) and quadratus lumborum (QL) blocks, provide effective postoperative abdominal analgesia. However, there is limited evidence on the analgesic efficacy of ESP and QL blocks after liver surgery. Therefore, we aimed to compare the cumulative opioid consumption between the ESP and QL blocks in patients with hepatocellular carcinoma undergoing laparoscopic liver resection.Patients and MethodsEighty-eight patients scheduled to undergo laparoscopic liver resection were randomized to receive bilateral single injection of ESP block at T8 (ESP group) or bilateral single injection of posterior QL block (QL group; 20 mL of 0.375% ropivacaine for each side, ie, total 150 mg of ropivacaine), in addition to intravenous (IV) fentanyl patient-controlled analgesia and multimodal analgesia. The primary outcome was cumulative opioid consumption over the first 24 h, expressed as IV morphine equivalents. Secondary outcomes included serial plasma ropivacaine concentrations, pain scores, time to first flatus, and Quality of Recovery-15 scores.ResultsEighty-five patients were analyzed (ESP group, n = 42; QL group, n = 43). Cumulative 24-h opioid consumption was similar between the ESP and QL groups (41.4 ± 22.6 mg vs 44.2 ± 20.0 mg, mean difference (QL-ESP), 2.8 mg, 95% confidence interval, −6.4 to 12 mg, p > 0.99). There were no significant differences in resting pain scores at 24, 48 and 72 h postoperatively or recovery outcomes. The peak plasma ropivacaine concentration 30 min after injection was significantly higher in the ESP group (1.5 ± 0.3 µg/mL) than in the QL group (1.3 ± 0.5 µg/mL, p = 0.035); however, both were lower than the arterial threshold value of systemic toxicity (4.3 µg/mL).ConclusionESP and QL blocks provided similar postoperative analgesia in patients undergoing laparoscopic liver resection.

Ultrasound-guided erector spinae plane block for postoperative analgesia in laparoscopic liver resection: A prospective, randomised controlled, patient and observer-blinded study.

Erector spinae plane block (ESPB) has been reported to manage postoperative pain effectively after various types of surgery. However, there has been a lack of study on the effect of ESPB after liver resection. To investigate the analgesic effects of ESPB on pain control after laparoscopic liver resection compared with conventional pain management. Prospective, randomised controlled study. A single tertiary care centre from February 2019 to February 2020. A total of 70 patients scheduled to undergo laparoscopic liver resection. In the control group (n = 35), no procedure was performed. In the ESPB group (n = 35), ESPB was performed after induction of general anaesthesia. A total of 40 ml of ropivacaine 0.5% was injected at the T9 level bilaterally. After surgery, intravenous fentanyl patient-controlled analgesia was initiated. Fentanyl and hydromorphone were administered as rescue analgesics. The primary outcome was the cumulative postoperative opioid consumption at 24 h (morphine equivalent). The secondary outcomes were rescue opioid (fentanyl) dose in the postanaesthesia care unit (PACU) and pain severity at 1, 6, 12, 24, 48 and 72 h, assessed using a numerical rating scale (NRS) score. The median [IQR] postoperative opioid consumption during 24 hours following surgery was 48.2 [17.1] mg in the control group and 45.5 [35.8] mg in the ESPB group (median difference, 4.2 mg; 95% CI, -4.2 to 13.3 mg; P = 0.259). Conversely, rescue opioid in PACU was 5.3 [5.0] mg in the control group and 3.0 [1.5] mg in the ESPB group (median difference, 2.5 mg; 95% CI, 1.0 to 5.0 mg; P < 0.001). There was no significant difference in NRS scores point between the groups at any time. ESPB does not provide analgesic effect within 24 h after laparoscopic liver resection. Clinical Trial Registry of Korea (https://cris.nih.go.kr.), identifier: KCT0003549).

Dynamic predictive model for postoperative nausea and vomiting for intravenous fentanyl patient-controlled analgesia.

Postoperative nausea and vomiting is the most common side-effect of opioid-based intravenous patient-controlled analgesia. Apfel's simplified risk score is popular but it has some limitations. We developed and validated a dynamic predictive model for nausea or vomiting up to 48 postoperative hours, available as an online web application. Fentanyl was used by 22,144 adult patients for analgesia after non-cardiac surgery under general anaesthesia: we randomly divided them into development (80%) and validation (20%) cohorts, repeated 100 times. We used linear discriminant analysis to select variables for multivariate logistic regression. The incidences of postoperative nausea or vomiting were: 0-48h, 5691/22,144 (26%); 0-6h, 2749/22,144 (12%); 6-12h, 2687/22,144 (12%); 12-18h, 2624/22,144 (12%); 18-24h, 1884/22,144 (9%); and 24-48h, 1082/22,144 (5%). The median (95%CI) area under the receiver operating characteristic curve was 0.72 (0.71-0.73) up to 48 postoperative hours compared with 0.65 (0.64-0.66) for the Apfel model, p<0.001. The equivalent areas for 0-6h, 6-12h, 12-18h, 18-24h and 24-48h were: 0.70 (0.69-0.72); 0.71 (0.69-0.73); 0.69 (0.68-0.71); 0.70 (0.67-0.72); and 0.69 (0.66-0.71), respectively. Our web application allows clinicians to calculate incidences of nausea and vomiting in patients receiving intravenous fentanyl for patient-controlled analgesia.

Patient-controlled analgesia with and without transverse abdominis plane and rectus sheath space block in cirrhotic patients undergoing liver resection

Background and Aims:Optimal pain control can be a challenge in cirrhotic patients. The aim was to compare the analgesic efficacy and side effects of intravenous fentanyl patient-controlled analgesia (PCA) with and without bupivacaine boluses in transversus abdominis plane (TAP) and rectus sheath space (RSB) in cirrhotics undergoing liver surgery.Material and Methods:A double-blinded randomized controlled trial (n = 55, child's A) was conducted. Catheters were inserted surgically in TAP and rectal sheath space during surgical closure. Fentanyl PCA + TAP + RSB group (gp) (n = 30): (0.2 ml/kg of 0.25% bupivacaine, 8 hourly) was compared with fentanyl PCA gp (n = 25): [0.2 ml/kg of saline (placebo) injected in catheters 8 hourly] for 48 h postoperatively. Plasma bupivacaine was measured with an enzyme-linked immunosorbent assay at 10 min, 30 min, 1 h, 2 h, and 4 h after each injection and 30 min before next injection.Results:Fentanyl consumption was reduced in (PCA + TAP + RSB) gp compared to PCA gp (Day 1: 325.4 ± 169.1 vs. 1034 ± 231.7, Day 2: 204.44 ± 62.9 vs. 481.6 ± 158.3 μg, P < 0.05). Both groups demonstrated effective pain control at rest [Visual Analog Scales (VAS) <3), but on movement pain control with bupivacaine was better (P < 0.05). Increased demand for rescue opioids was observed prior to next scheduled bupivacaine injection in 10/30 patients on Day 1 and 2/30 on Day 2, in association with a reduced bupivacaine serum levels compared to 10 min after injection (47.6 ± 22.7 vs. 93.6 ± 61.0 ng/ml, respectively, P < 0.05). Bupivacaine did not exceed referred toxic levels.Conclusion:Repeated bupivacaine TAP and RSB with PCA fentanyl improved pain control, reduced opioids demand with no toxicity. Time interval between injections needs to be reduced to avoid breakthrough pain.

Comparison of analgesic efficacy between two approaches of paravertebral block for thoracotomy: A randomised trial

Although several approaches for ultrasound-guided thoracic paravertebral block have been introduced, little is known regarding the differences in analgesic efficacy. We conducted this prospective randomised trial to examine whether the type of approach for ultrasound-guided thoracic paravertebral block could affect analgesic quality in thoracotomy. Patients scheduled for video-assisted thoracotomy were randomly allocated into two groups by block technique: the intercostal approach (group IC) or the paralaminar approach (group PL). At the start and end of surgery, 20mL of 0.5% ropivacaine was injected, followed by a continuous infusion of 0.2% ropivacaine at 5mL h-1 . We also started intravenous fentanyl patient-controlled analgesia at 0.5μg kg-1 h-1 and bolus dose of 15μg. The main outcome was the number of rescue fentanyl use. We also evaluated postoperative pain scores and number of blocked dermatomes showing a reduced sensation. Enrolment was ceased because of implementation of a minimally invasive surgical method. Overall, 42 subjects completed the trial for analysis. The number of rescue fentanyl use in group PL was significantly less than that in group IC at 3, 6, 12 and 24hour postoperatively. The numerical rating scale (NRS) at rest in group PL was significantly lower at 1, 3, 6, and 12hour postoperatively. Patients in Group PL developed significantly wider sensory block level (median (IQR [range]); 4 (4-5 [2-7])) than those in Group IC (3 (3-3 [2-9])). We suggested that paralaminar approach provided superior analgesia for thoracotomy rather than the intercostal approach.

Continuous transversus abdominis plane block vs intermittent bolus for analgesia after abdominal surgery: a randomized trial

BackgroundContinuous and intermittent bolus techniques of transversus abdominis plane (TAP) blocks have been used for analgesia after abdominal surgery. Although both are effective, there are no studies comparing them. The aim of this study is to compare analgesia and cost-effectiveness between these groups.MethodsAfter obtaining ethical approval, 20 American Society of Anesthesiologists ASA grade I to III patients undergoing elective abdominal surgery were recruited with 10 patients allocated to each arm. Bilateral ultrasound-guided TAP blocks were performed with an initial bolus of 0.5% ropivacaine 20 mL per side, followed by catheter insertion. After surgery, the continuous infusion group received 0.2% ropivacaine 8 mL/hour on each side and the intermittent bolus group received doses of 0.2% ropivacaine 20 mL per side every 8 hours for 48 hours. Both groups received intravenous fentanyl patient-controlled analgesia and regular oral paracetamol. Parameters recorded included numerical rating scores for pain and post-operative analgesic consumption at baseline (time 0) and at 1 hour, 1 day and 2 days post-operatively. The duration of catheter insertion, complications, patient satisfaction and information regarding costs were also recorded. Patient satisfaction was assessed utilizing a 4-point “Likert” scale on day 2 and on day 30. Pain and Likert scores were analysed by non-parametric sum rank test and all two-sampled t-tests assumed unequal variances.ResultsThere was no difference between duration of TAP block, anesthetic and surgical technique and length of stay (p=0.23). Primary outcomes: pain scores at rest and cough were not significantly different (p=0.20) between the groups. Satisfaction scores were similar at day 2 and 30 (p=0.77). However, the bolus group was more cost-effective (AU$347.98 vs AU$429.43).ConclusionContinuous or bolus TAP blocks are effective analgesic techniques in abdominal surgery, with bolus technique being more economical.

Effect of naloxone on intravenous fentanyl patient-controlled analgesia after laparoscopic cholecystectomy.

This study aims to evaluate the effect of naloxone on intravenous fentanyl patient-controlled analgesia after laparoscopic cholecystectomy under total intravenous anesthesia.A total of 90 patients, who underwent intravenous fentanyl patient-controlled analgesia after laparoscopic cholecystectomy under total intravenous anesthesia, were included into this study. All patients were randomly divided into 3 groups (each group, n=30): naloxone group (naloxone+fentanyl), tropisetron group (tropisetron+fentanyl), and fentanyl group (fentanyl). Patients in each group were given a corresponding dose of naloxone. Postoperative analgesia effect and the incidence of side effects such as nausea and vomiting were observed.Small doses of naloxone or tropisetron combined with fentanyl used for intravenous patient-controlled analgesia can significantly reduce the incidence of nausea and vomiting. Six hours after surgery, visual analogue scale (VAS) scores were significantly lower in patients that underwent intravenous patient-controlled analgesia using low-dose naloxone combined with fentanyl compared with patients who received fentanyl alone; however, the postoperative analgesic effect of tropisetron was not observed. Compared with the combination of tropisetron and fentanyl, low-dose naloxone combined with fentanyl can obviously reduce the incidence of nausea and vomiting in patients who underwent intravenous patient-controlled analgesia after laparoscopic cholecystectomy, and enhance the analgesic effect of fentanyl 6 hours after surgery.Low-dose naloxone can reduce the incidence of nausea and vomiting in patients who underwent laparoscopic cholecystectomy under total intravenous anesthesia, and exhibits a certain synergic analgesic effect.

Rectus sheath block for postoperative analgesia in patients with mesenteric vascular occlusion undergoing laparotomy: A randomized single-blinded study.

Background:Acute mesenteric ischemia is a life-threatening vascular emergency that requires early diagnosis, immediate anticoagulation, and intervention to restore mesenteric blood flow adequately.Aims:To investigate the effect of rectus sheath block (RSB) for postoperative analgesia in patients with mesenteric vascular occlusion.Settings and Design:Forty patients with mesenteric vascular occlusion, American Society of Anesthesiologists physical status I or II or III, scheduled for laparotomy were enrolled in this study.Subjects and Methods:Patients were randomized into two groups; control group (C Group) and rectus block group (RB Group). In both groups, general anesthesia was induced fentanyl 1 μg/kg with sleeping dose of propofol and 0.15 mg/kg cisatracurium. Then, anesthesia was maintained with sevoflurane in oxygen 100%. In RB Group, under aseptic condition, RSB guided by ultrasound was performed. Surgery is then continued and intravenous fentanyl patient-controlled analgesia pump started. Postoperative pain, sedation, and opioid side effects were assessed.Statistical Analysis Used:Statistical analysis was done using Statistical Package for Social Sciences (SPSS 19.0, Chicago, IL, USA).Results:Patients in the RB Group consumed statistically significant less opioid in comparison to control group either intraoperatively or postoperatively. Mean pain scores were statistically significant less in RB Group than in the control group at 2, 4, and 6 h postoperatively. Sedation score, incidence of nausea and vomiting were statistically significant less in the RB Group in comparison to control group. More patients’ satisfaction was reported in the RB Group.Conclusions:Ultrasound-guided RSB resulted in postoperative reduction of pain scores and opioid consumption compared with general anesthesia alone. Moreover, RSB was associated with better patient satisfaction and less nausea and vomiting.

Intravenous patient-controlled fentanyl with and without transversus abdominis plane block in cirrhotic patients post liver resection.

BackgroundCoagulation changes can complicate liver resection, particularly in patients with cirrhosis. The aim of this prospective hospital-based comparative study was to compare the postoperative analgesic efficacy of intravenous fentanyl patient-controlled analgesia (IVPCA) with and without transversus abdominis plane (TAP) block.MethodsFifty patients with Child’s A cirrhosis undergoing liver resection were randomly divided into two groups for postoperative analgesia, ie, an IVPCA group receiving a 10 μg/mL fentanyl bolus of 15 μg with a 10-minute lockout and a maximum hourly dose of 90 μg, and an IVPCA + TAP group that additionally received TAP block (15 mL of 0.375% bupivacaine) on both sides via a posterior approach with ultrasound guidance before skin incision. Postoperatively, bolus injections of bupivacaine 0.375% were given every 8 hours through a TAP catheter inserted by the surgeon in the open space during closure of the inverted L-shaped right subcostal with midline extension (subcostal approach) guided by the visual analog scale score (<3, 5 mL; 3 to <6, 10 mL; 6–10, 15–20 mL) according to weight (maximum 2 mg/kg). The top-up dosage of local anesthetic could be omitted if the patient was not in pain. Coagulation was monitored using standard coagulation tests.ResultsAge, weight, and sex were comparable between the groups (P>0.05). The visual analog scale score was significantly lower at 12, 18, 24, 48, and 72 hours (P<0.01) in IVPCA + TAP group. The Ramsay sedation score was lower only after 72 hours in the IVPCA + TAP group when compared with the IVPCA group (1.57±0.74 versus 2.2±0.41, respectively, P<0.01). Heart rate, systolic blood pressure, and fentanyl consumption were lower in the IVPCA + TAP group at 24, 48, and 72 hours (P<0.05). Intensive care unit stays were significantly shorter with TAP (2.61±0.74 days versus 4.35±0.79 days, P<0.01). Prothrombin time and International Normalized Ratio indicated temporary hypocoagulability in both groups.ConclusionCombining TAP with IVPCA improved postoperative pain management and reduced fentanyl consumption, with a shorter stay in intensive care. TAP block can be included as part of a balanced multimodal postoperative pain regimen.

Poor Analgesic Efficacy of Epidural Analgesia in Critical Care Patients After Pancreaticoduodenectomy

The objective of this study was to investigate the analgesic efficacy of functional and prematurely aborted epidurals after pancreaticoduodenectomy in critical care, as this is unknown. Data from elective pancreaticoduodenectomy recipients admitted to the critical care unit over 44 months were prospectively collected. Epidural (0.1% bupivacaine and 2 µg/mL fentanyl) analgesic efficacy was assessed with a ranked categorical verbal pain score (primary end point). If no epidural was placed, intravenous (IV) fentanyl patient-controlled analgesia (PCA) was used. Eighty-six pancreaticoduodenectomy patients had a mean age of 66.5 years; 61.6% were men; and 73 received an epidural, whereas 13 received an IV PCA. Epidural abortion rate was 42.5%, associated with a higher 24-hour (P = 0.02) but not 48-hour pain score. Overall, fewer patients reported any pain (P = 0.010; number needed to harm, 3.2; 95% confidence interval, 1.7-3.2) or severe pain (P = 0.006; number needed to harm, 2.9; 95% confidence interval, 2.1-4.7) with functional epidurals. Pain (sensitivity, 93.8%) and severe pain (specificity, 87.8%) were predictive of epidural abortion. Most postepidural analgesia was IV PCA (P = 0.097) after both functional and aborted epidurals. Premature epidural abortion rate was high and associated with analgesic morbidity. Pain score was predictive of epidural abortion. Thus, preference toward epidural analgesia cannot be supported.

Retrospective evaluation of intravenous fentanyl patient-controlled analgesia during labor

Because the safety of intravenous fentanyl patient-controlled analgesia (iv-PCA) administered during labor remains unclear, we retrospectively examined the labor records from January 2005 to December 2007 in our institution, with a focus on both maternal and neonatal outcomes, as compared to no analgesia. Parturients over 35weeks of gestational age who received fentanyl iv-PCA (iv-PCA group) or no analgesia (control group) during labor were enrolled. The former group received iv-PCA through a pump programmed to give a loading dose of 0.05mg fentanyl, followed by bolus injection of 0.02mg fentanyl, with a lock-out interval of 5min. This analgesia was initiated at the parturient's request and was discontinued before the second stage of labor, to ensure neonatal safety. During labor, both maternal and fetal heart rates, maternal pulse oximeter oxygen saturation (SpO(2)), respiratory rate, and sedation and nausea scores were continuously monitored, and the neonatal outcomes including umbilical arterial pH, Apgar scores, and other parameters were recorded. The data of 129 of the 143 parturients who received fentanyl iv-PCA were analyzed, while 697 parturients delivered without any analgesia during the 3-year study period. While iv-PCA prolonged the duration of labor and increased oxytocin use, no obvious maternal or neonatal complications of fentanyl use were recorded. Except for the significantly lower rate of emergency cesarean section in the iv-PCA group, both the maternal and neonatal outcomes were comparable between the groups. As compared to no analgesia, fentanyl iv-PCA appears to be safe and clinically acceptable as analgesia during labor, particularly in nulliparous women.

Effect of CYP3A4*1G on the fentanyl consumption for intravenous patient-controlled analgesia after total abdominal hysterectomy in Chinese Han population

Clinical investigations into postoperative intravenous patient-controlled analgesia (PCA) have indicated interindividual differences in fentanyl consumption. Cytochrome P450 3A4 (CYP3A4) is the main metabolism enzyme of fentanyl, and single nucleotide polymorphisms within the CYP3A4 gene may contribute to the variability of fentanyl analgesic efficacy. The aim of this study was to investigate whether the most common genetic variation in Chinese, CYP3A4*1G, has an impact on the fentanyl consumption for intravenous PCA in Chinese Han women undergone abdominal total hysterectomy. A total of 79 female patients (American Society of Anesthesiologist physical status I or II) scheduled to undergo elective abdominal total hysterectomy were enrolled. All patients received combined spinal-epidural anaesthesia with bupivacaine. Intravenous fentanyl PCA was provided postoperatively for satisfactory analgesia. The doses of fentanyl consumption were recorded 2, 4, 24 and 48 h after the initiation of PCA postoperatively. Pain at rest and adverse effects were measured with rating scales. CYP3A4*1G was screened by means of direct sequencing and further confirmed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Forty-six patients were GG homozygotes, 27 patients were GA heterozygotes, and six patients were AA homozygotes, respectively. The distribution of the CYP3A4*1G allele was consistent with Hardy-Weinberg equilibrium (P>0·05). At 2 and 4 h, the doses of fentanyl required for patients with GA/AA genotypes were 80·0 (45·0, 112·5) μg and 120·0 (80, 173·8)μg, respectively, and significantly lower than those for GG homozygotes [91·3 (80·0, 125·0) μg and 169·0 (112·5, 226·3) μg, respectively, P<0·05]. There was trend of decreasing fentanyl consumption at 24 and 48h in patients with GA/AA genotypes, relative to GG homozygotes, but the difference was not statistical significant (P>0·05). CYP3A4*1G has an impact on the analgesic effect of fentanyl in Chinese Han subjects. Further validation of our results in a well-powered study would be helpful.

Influence of CYP3A5*3 polymorphism and interaction between CYP3A5*3 and CYP3A4*1G polymorphisms on post-operative fentanyl analgesia in Chinese patients undergoing gynaecological surgery

Fentanyl is metabolised by cytochrome P450 (CYP) 3A4 and CYP3A5. Our previous work demonstrated that the CYP3A4*1G polymorphism significantly affects the post-operative fentanyl analgesic effect in Chinese women undergoing gynaecological surgery. However, whether CYP3A5*3, a frequent single nucleotide polymorphism of CYP3A5 in Chinese people, affects the post-operative analgesic effect of fentanyl is unclear. In this study, we assessed the influence of the CYP3A5*3 polymorphism and the interaction of the CYP3A5*3 and CYP3A4*1G polymorphisms on post-operative fentanyl analgesia in Chinese women undergoing gynaecological surgery. We enrolled 203 women scheduled for abdominal total hysterectomy or myomectomy under general anaesthesia. Intravenous fentanyl patient-controlled analgesia was provided post-operatively for adequate analgesia. Pain scores and fentanyl consumption were recorded 24 h post-operatively. Midazolam was used as a probe drug, and CYP3A activity was measured by plasma ratio of 1'-hydroxymidazolam to midazolam 1 h after intravenous administration of 0.1 mg kg-1 midazolam. Blood samples were genotyped for the CYP3A5*3 polymorphism. The frequency of the CYP3A5*3 allele was 72.4% in 203 patients. CYP3A activity did not differ among CYP3A5*3 genotypes. Fentanyl consumption 24 h post-operatively was lower with CYP3A5*1/*3 and CYP3A5*3/*3 polymorphisms than with CYP3A5*1/*1, but the differences were not statistically significant. However, combined with CYP3A4*1G polymorphism, post-operative fentanyl consumption at 24 h was significantly lower for the CYP3A5*1/*3 or CYP3A5*3/*3 group than the CYP3A5*1/*1 group. CYP3A5*3 is not the main genetic factor contributing to interindividual variation in the post-operative analgesic effect of fentanyl in Chinese women undergoing gynaecological surgery; an interaction between CYP3A5*3 and CYP3A4*1G polymorphisms can significantly influence the post-operative effect.

CASE REPORT: Intravenous fentanyl patient-controlled analgesia for perioperative treatment of neuropathic/ischaemic pain in haemodialysis patients: a case series

Use of opioids is common in perioperative haemodialysis patients because they often suffer from intractable ischaemic or neuropathic lower extremity pain. Intravenous (IV) fentanyl, patient-controlled analgesia (PCA) does not appear to have been evaluated in this setting; hence this study. This is a prospective, single-centre study. IV fentanyl PCA was used for pain control in 16 patients with lower extremity, neuropathic/ischaemic pain, scheduled for major lower extremity amputation. IV fentanyl PCA was used before and after amputation in eight patients, before but not after amputation in seven patients, and until death in one terminal cancer patient who chose to forgo surgery. Pain intensity was assessed with the Visual Analogue Scale (VAS) and the McGill Pain Questionnaire. Depth of sedation was assessed on a 4-point scale. Ischaemic pain scores were high before fentanyl PCA started, but decreased significantly and remained low with fentanyl PCA use (P<0·001). Phantom pain scores were low (VAS≤4). Respiratory depression was not a problem in any patient. Concerns about accumulation of active opioid metabolites make provision of adequate analgesia problematic in haemodialysis patients scheduled for amputation, and emergency surgery. Our data on a small patient population suggest that IV fentanyl PCA is safe and effective for severe pain in haemodialysis patients.

Association of human μ‐opioid receptor gene polymorphism A118G with fentanyl analgesia consumption in Chinese gynaecological patients

One hundred and seventy-four Chinese gynaecology patients were studied for the impact of A118G polymorphism in the micro-opioid receptor gene (OPRM1) on pain sensitivity and postoperative fentanyl consumption. Pre-operatively, the pain threshold and pain tolerance threshold were measured using electrical stimulation. A118G polymorphism was genotyped using the polymerase chain reaction-restriction fragment length polymorphism method. Intravenous fentanyl patient-controlled analgesia provided postoperative pain management, assessed using a visual analogue scale and fentanyl consumed in the first 24 h after surgery was noted. We found the prevalence of G118 allele was 31.3%. The A118G polymorphism had a gene-dose-dependent effect on electrical pain tolerance threshold. Fentanyl consumption was also significantly different in patients with different OPRM1 genotypes (homozygotes for 118G consumed more than did heterozygotes or homozygotes for 118A). Fentanyl consumption increased in accordance with the number of 118G alleles. We conclude that OPRM1 gene analysis may help predict individual opioid sensitivity and so optimise postoperative pain control.

CYP3A4*1G genetic polymorphism influences CYP3A activity and response to fentanyl in Chinese gynecologic patients

To investigate whether the CYP3A4*1G genetic polymorphism contributes to the variability in CYP3A activity and response to fentanyl. One hundred and forty-three gynecologic patients who were scheduled to undergo abdominal total hysterectomy or myomectomy with general anesthesia were enrolled in this study. Intravenous fentanyl patient-controlled analgesia was provided postoperatively for satisfactory analgesia. The degrees of pain at rest during PCA treatment were assessed with visual analog scale. The fentanyl consumption and occurrence of any adverse effects were recorded in the first 24 h postoperatively. CYP3A activity was measured by plasma 1'-hydroxymidazolam-to-midazolam ratio 1 h after intravenous administration of 0.1 mg/kg midazolam. CYP3A4*1G variant allele was genotyped using the polymerase chain reaction-restriction fragment length polymorphism method. The frequency of the CYP3A4*1G variant allele was 0.269 in 143 Chinese gynecologic patients. The activity of CYP3A4 in patients homozygous for the *1G/*1G variant (0.34 +/- 0.15) was significantly lower than that in patients bearing the wild-type allele (*1/*1) (0.46 +/- 0.14) or in patients heterozygous for the *1/*1G variant (0.46 +/- 0.12) (P < 0.05). The patients with the CYP3A4*1G/*1G genotype needed less fentanyl (227.8 +/- 55.2 microg) to achieve pain control than patients carrying the CYP3A4*1/*1 (381.6 +/- 163.6 microg) and CYP3A4*1/*1G (371.9 +/- 180.1 microg) genotypes (P < 0.05) during the first 24 h postoperatively. There was no significant difference in incidence of adverse events among the different genotype groups (P > 0.05). CYP3A4*1G genetic polymorphism decreases CYP3A activity and fentanyl consumption for postoperative pain control.