Ban Leong Sng

A comparison between remifentanil and meperidine for labor analgesia: a systematic review.

BACKGROUND:Remifentanil is an ultrashort-acting opioid with favorable pharmacokinetic properties that make it suitable as a labor analgesic. Although it crosses the placenta freely, it is eliminated quickly in the neonate by rapid metabolism and redistribution. We aimed to determine whether remifentanil compared with meperidine is effective in reducing pain scores in laboring parturients. Other effects on the mother, the labor process, and the neonate were also examined. METHODS:MEDLINE, CINAHL, Embase, Cochrane CENTRAL, and Maternity and Infant Care databases were searched without language restriction using multiple keywords for labor analgesia, remifentanil, and meperidine. Published abstracts from 5 key research meetings and references from retrieved articles were examined for additional studies. Randomized controlled trials in laboring parturients comparing remifentanil with meperidine were selected. Risk of bias was assessed using criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We assessed for adequacy of sequence generation, allocation concealment, blinding, and completeness of follow-up. Data were extracted from each study using a standardized data collection form. The primary outcome was reduction in pain scores (visual analog scale [VAS], 0–100 mm). We also evaluated maternal side effects (sedation, oxygen desaturation, and bradypnea) and effects on the neonate (Apgar scores, umbilical cord pH, and Neurologic and Adaptive Capacity Scores). RESULTS:Seven studies (349 patients) were identified for inclusion; only 3 studies were suitable for quantitative synthesis in a meta-analysis (233 patients). We found that remifentanil reduces the mean VAS score at 1 hour by 25 mm more than meperidine (P < 0.001) (95% confidence interval = 19–31 mm). Limited conclusions can be made regarding the side-effect profile of remifentanil because of insufficient data. CONCLUSION:Compared with meperidine, remifentanil is superior in reducing mean VAS scores for labor pain after 1 hour.

A Randomized Comparison of Low Doses of Hyperbaric Bupivacaine in Combined Spinal-Epidural Anesthesia for Cesarean Delivery

BACKGROUND: The aim of our study was to investigate the block characteristics of intrathecal hyperbaric bupivacaine 7, 8, or 9 mg administered during combined spinal-epidural anesthesia for cesarean delivery and to elucidate the dose that produces adequate sensory blockade for surgery while minimizing the incidence of hypotension, high neuroblockade, and the need for intraoperative epidural supplementation. METHODS: Sixty women presenting for elective cesarean delivery were randomly assigned to one of the 3 groups. Group 7 received intrathecal hyperbaric bupivacaine 7 mg, Group 8 received 8 mg, and Group 9 received 9 mg. Women in all 3 groups received intrathecal morphine 100 &mgr;g and IV hydroxyethyl starch 15 mL/kg at the time of initiation of combined spinal-epidural anesthesia. Surgery began when a sensory level of T4 was achieved. Patients were monitored for block characteristics and side effects by a blinded observer. Our primary outcome was the maximum cephalad sensory block height. RESULTS: There was a difference in the maximum extent of cephalad sensory block among groups (Group 7: median T2 [interquartile range T2–T3]; Group 8: median T2 [T1–T2]; Group 9: median T1 [C8–T2]; P = 0.02). However, the time taken to reach T4 was similar in all 3 groups. The incidence of hypotension requiring vasopressors was different among groups (30% in Group 7, 55% in Group 8, and 70% in Group 9; P = 0.04). No patient had inadequate anesthesia. Neonatal outcomes were similar in all 3 groups. CONCLUSION: The lowest dose of hyperbaric bupivacaine (7 mg) provided equally rapid onset and effective anesthesia for cesarean delivery while reducing the incidence of hypotension compared with 8 and 9 mg. However, because of its shorter duration of anesthesia, it may be feasible only when the block can be reinforced using a functional epidural catheter.

Assessment of an updated double‐vasopressor automated system using Nexfin™ for the maintenance of haemodynamic stability to improve peri‐operative outcome during spinal anaesthesia for caesarean section

Hypotension occurs commonly during spinal anaesthesia for caesarean section, associated with maternal and fetal adverse effects. We developed a double‐vasopressor automated system with a two‐step algorithm and continuous non‐invasive haemodynamic monitoring using the Nexfin™ device. The system delivered 25 μg phenylephrine every 30 s when systolic blood pressure was between 90% and 100% of baseline, or 2 mg ephedrine at this blood pressure range and heart rate < 60 beats.min−1; and 50 μg phenylephrine or 4 mg ephedrine when systolic blood pressure was < 90% of baseline with the same heart rate criterion. Fifty‐seven women received standardised spinal anaesthesia. Twenty‐seven (47.4%) had at least one reading of hypotension defined as systolic blood pressure < 80% baseline. Systolic blood pressure was within 20% of the baseline in a mean (SD) of 79.8 (20.9)% of measurements. Fifty‐three (93.0%) women required phenylephrine before delivery while 10 (17.5%) required ephedrine. Six women (10.5%) experienced nausea and three (5.3%) vomited. The system was able to achieve a low incidence of maternal hypotension with good maternal and fetal outcomes.

Investigating analgesic and psychological factors associated with risk of postpartum depression development: a case–control study

Aim The aim of this study was to investigate the role of peripartum analgesic and psychological factors that may be related to postpartum depression (PPD). Methods This case–control study was conducted in pregnant females who delivered at KK Women’s and Children’s Hospital from November 2010 to October 2013 and had postpartum psychological assessment. Demographic, medical, and postpartum psychological status assessments, intrapartum data including method of induction of labor, mode of labor analgesia, duration of first and second stages of labor, mode of delivery, and pain intensity on hospital admission and after delivery were collected. PPD was assessed using the Edinburgh Postnatal Depression Scale and clinical assessment by the psychiatrist. Results There were 62 cases of PPD and 417 controls after childbirth within 4–8 weeks. The odds of PPD was significantly lower (33 of 329 [10.0%]) in females who received epidural analgesia for labor compared with those who chose nonepidural analgesia (29 of 150 [19.3%]) ([odds ratio] 0.47 (0.27–0.8), P=0.0078). The multivariate analysis showed that absence of labor epidural analgesia, increasing age, family history of depression, history of depression, and previous history of PPD were independent risk factors for development of PPD. Conclusion The absence of labor epidural analgesia remained as an independent risk factor for development of PPD when adjusted for psychiatric predictors of PPD such as history of depression or PPD and family history of depression.

A case series of vital signs-controlled, patient-assisted intravenous analgesia (VPIA) using remifentanil for labour and delivery

Intravenous remifentanil patient‐controlled analgesia can be used during labour as an alternative to epidural analgesia. Adverse effects of opioids, including hypoxia and bradycardia, may lead to maternal morbidity and mortality. We devised an interactive feedback system based on a clinical proportional algorithm, to continuously monitor for adverse effects to enhance safety and better titrate analgesia. This vital signs‐controlled, patient‐assisted intravenous analgesia with remifentanil used a prototype delivery system linked to a pulse oximeter that evaluated maternal oxygen saturation and heart rate continuously. With this system, we detected oxygen saturation < 95% for more than 60 s in 15 of 29 subjects (52%); and heart rate < 60 min−1 for more than 60 s in 7 of 29 subjects (24%) during use. The system automatically responded appropriately by reducing the dosages and temporarily halting remifentanil administration, thus averting further hypoxia and bradycardia.

Legal and ethical issues in research

Legal and ethical issues form an important component of modern research, related to the subject and researcher. This article seeks to briefly review the various international guidelines and regulations that exist on issues related to informed consent, confidentiality, providing incentives and various forms of research misconduct. Relevant original publications (The Declaration of Helsinki, Belmont Report, Council for International Organisations of Medical Sciences/World Health Organisation International Guidelines for Biomedical Research Involving Human Subjects, World Association of Medical Editors Recommendations on Publication Ethics Policies, International Committee of Medical Journal Editors, CoSE White Paper, International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use-Good Clinical Practice) form the literature that are relevant to the ethical and legal aspects of conducting research that researchers should abide by when conducting translational and clinical research. Researchers should note the major international guidelines and regional differences in legislation. Hence, specific ethical advice should be sought at local Ethics Review Committees.

Real-time automatic spinal level identification with ultrasound image processing

In this paper, we propose an ultrasound image processing procedure for fully automatic lumbar spine level identification. The image processing procedure starts with automatic sacrum identification, with feature selection and support vector machine (SVM) classification. After sacrum is detected, a panorama image stitching procedure is initiated to obtain the overall spinous processes structure. Throughout the image stitching and ultrasound probe movement, an image quality evaluation standard is utilized to select the suitable frames to be stitched onto the panorama image, so as to eliminate the accidental bad-quality frames in case the probe goes out-of-line during the scanning movement. In the meantime, the spinous levels are identified and counted on the panorama image, which are then reflected on the original ultrasound image in real time, so as to inform anesthetists where is the level L3-L4 and when to stop scanning. The processing result with off-line collected lumbar ultrasound videos shows a high accuracy on sacrum identification and spinous level identification.

Incidence and characteristics of breakthrough pain in parturients using computer-integrated patient-controlled epidural analgesia

INTRODUCTION The computer-integrated patient-controlled epidural analgesia (CIPCEA) system can automatically adjust the background infusion rate during combined spinal-epidural analgesia based on the parturients need, as labor progresses. OBJECTIVES The objective is to identify risk factors associated with breakthrough pain during labor as well as identify obstetric and fetal outcomes that are affected by breakthrough pain. DESIGN This is a retrospective review of prospectively collected data. SETTING The setting is in a delivery room. PARTICIPANTS The participants are 280 nulliparous women in early labor (≤5 cm cervical dilatation) who received combined spinal-epidural analgesia with CIPCEA. INTERVENTIONS The intervention is CIPCEA. MEASUREMENTS The primary outcome is the incidence of breakthrough pain (≥1 episodes of pain or pressure that required supplemental epidural medications) during labor. Relevant demographic, anesthetic, obstetric, and fetal characteristics were also measured. Univariate and multivariate analyses were performed to identify obstetric and anesthetic factors that were associated with increased incidence of breakthrough pain as well as to evaluate the impact of breakthrough pain on obstetric and fetal outcomes. RESULTS The incidence of breakthrough pain was 9.6%. Independent factors associated with incidence of breakthrough pain are the presence of dysfunctional labor, increased maternal body mass index, and decreased successful-to-total-bolus-demand ratio. The postlabor characteristics independently associated with breakthrough pain were increased duration of labor, decreased duration of effective analgesia, increased total local anesthetic consumption, and decreased maternal satisfaction. CONCLUSIONS Low successful to total patient demand bolus ratio was the factor with the strongest association with breakthrough pain. Breakthrough pain was also associated with dysfunctional labor and poorer maternal satisfaction.

Hyperbaric vs. isobaric bupivacaine for spinal anaesthesia for elective caesarean section: a Cochrane systematic review

Both isobaric and hyperbaric bupivacaine have been used for spinal anaesthesia for elective caesarean section, but it is not clear if one is better than the other. The primary objective of this systematic review was to determine the effectiveness and safety of hyperbaric bupivacaine compared with isobaric bupivacaine administered during spinal anaesthesia for elective caesarean section. We included 10 studies with 614 subjects in the analysis. There was no evidence of differences either in the risk of conversion to general anaesthesia, with a relative risk (95%CI) of 0.33 (0.09–1.17) (very low quality of evidence), or in the need for supplemental analgesia, the relative risk (95%CI) being 0.61 (0.26–1.41) (very low quality of evidence). There was also no evidence of a difference in the use of ephedrine, the amount of ephedrine used, nausea and vomiting, or headache. Hyperbaric bupivacaine took less time to reach a sensory block height of T4, with a mean difference (95%CI) of −1.06 min (−1.80 to −0.31). Due to the rarity of some outcomes, dose variability, use of adjuvant drugs and spinal technique used, future clinical trials should look into using adequate sample size to investigate the primary outcome of the need for supplemental analgesia.

Comparison of epidural oxycodone and epidural morphine for post-caesarean section analgesia: A randomised controlled trial.

Background and Aims: Epidural morphine after caesarean section may cause moderate to severe pruritus in women. Epidural oxycodone has been shown in non-obstetric trials to reduce pruritus when compared to morphine. We hypothesised that epidural oxycodone may reduce pruritus after caesarean section. Methods: A randomised controlled trial was conducted in pregnant women at term who underwent caesarean section with combined spinal-epidural technique initiated with intrathecal fentanyl 15 μg. Women received either epidural morphine 3 mg or epidural oxycodone 3 mg via the epidural catheter after delivery. The primary outcome was the incidence of pruritus at 24 h after caesarean section. The secondary outcomes were the pruritus scores, treatment for post-operative nausea and vomiting (PONV), pain scores and maternal satisfaction. Results: One hundred women were randomised (group oxycodone O = 50, morphine M = 50). There was no difference between Group O and M in the incidence of pruritus (n [%] 28 [56%] vs. 31 [62%], P = 0.68) and the worst pruritus scores (mean [standard deviation] 2.6 (2.8) vs. 3.3 [3.1], P = 0.23), respectively. Both groups had similar pain scores at rest (2.7 [2.3] vs. 2.0 [2.7], P = 0.16) and sitting up (5.0 [2.3] vs. 4.6 [2.4], P = 0.38) at 24 h. Pruritus scores were lower at 4–8, 8–12 and 12–24 h with oxycodone, but pain scores were higher. Both groups had a similar need for treatment of PONV and maternal satisfaction with analgesia. Conclusion: There was no difference in the incidence of pruritus at 24 h between epidural oxycodone and morphine. However, pruritus scores were lower with oxycodone between 4 and 24 h after surgery with higher pain scores in the same period.