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OBJECTIVE: Oxytocin is frequently used by intravenous bolus and infusion to minimize blood loss and prevent postpartum hemorrhage at cesarean delivery. Current dosing regimens are arbitrary whereas large doses may pose a serious risk to the mother. The purpose of this study was to estimate the minimum effective intravenous bolus dose of oxytocin (ED90) required for adequate uterine contraction at elective cesarean in nonlaboring women. METHODS: A randomized, single-blinded study was undertaken in 40 healthy term pregnant women presenting for elective cesarean under spinal anesthesia. Oxytocin was administered by bolus according to a biased coin up-and-down sequential allocation scheme with increments or decrements of 0.5 IU. Uterine contraction was assessed by the obstetrician, who was blinded to the dose of oxytocin, as either satisfactory or unsatisfactory. After achieving sustained uterine contraction, an infusion of 40 mU/min of oxytocin was started. Oxytocin-induced adverse effects and intraoperative complications were recorded and blood loss was estimated. Data were interpreted by parametric analysis based on logistic regression model and nonparametric analyses at 95% confidence intervals (CIs). RESULTS: The ED90 of oxytocin as determined by logistic regression model fitted to the data was estimated to be 0.35 IU (95% CI 0.18-0.52 IU), with nonparametric estimates of 97.1% (95% CI 84.9-99.8%) response rate at 0.5 IU, and 100% (95% CI 92.2-100%) at 1.0 IU. The estimated blood loss was 693 +/- 487 mL (mean +/- standard deviation). CONCLUSION: The bolus dose of oxytocin used at elective cesarean deliveries in nonlaboring women can be significantly reduced while maintaining effective uterine contraction. Alteration in practice will likely reduce the potential adverse effects of this drug when given in large bolus doses, but may require modification of the techniques to remove the placenta. [ABSTRACT FROM AUTHOR]

Competing Interests: Conflicts of Interest, Funding: Please see DISCLOSURES at the end of this article.

Objectives: Enhanced recovery after surgery (ERAS) protocols are multimodal evidence-based care plans that have been adopted for multiple surgical procedures to promote faster and better patient recovery and shorter hospitalization. This study aimed to explore whether worldwide fetal therapy centers offering prenatal myelomeningocele repair implement the ERAS principles and to provide recommendations for improved perioperative management of patients., Methods: In this survey study, a total of 53 fetal therapy centers offering prenatal surgery for open spina bifida were identified and invited to complete a digital questionnaire covering their pre-, intra- and postoperative management. An overall score was calculated per center based on compliance with 20 key ERAS principles, extrapolated from ERAS guidelines for Cesarean section, gynecological oncology and colorectal surgery. Each item was awarded a score of 1 or 0, depending, respectively, on whether the center did or did not comply with that principle, with a maximum score of 20., Results: The questionnaire was completed by 46 centers in 17 countries (response rate, 87%). In total, 22 (48%) centers performed exclusively open fetal surgery (laparotomy and hysterotomy), whereas 14 (30%) offered both open and fetoscopic procedures and 10 (22%) used only fetoscopy. The perioperative management of patients undergoing fetoscopic and open surgery was very similar. The median ERAS score was 12 (range, 8-17), with a mean ± SD of 12.5 ± 2.4. Center compliance was the highest for the use of regional anesthesia (98%), avoidance of bowel preparation (96%) and thromboprophylaxis (96%), while the lowest compliance was observed for preoperative carbohydrate loading (15%), a 2-h fasting period for clear fluids (20%), postoperative nausea and vomiting prevention (33%) and early feeding (35%). ERAS scores were similar in centers with a short (2-5 days), medium (6-10 days) and long (≥ 11 days) hospital stay (mean ± SD, 12.9 ± 2.4, 12.1 ± 2.0 and 10.3 ± 3.2, respectively, P = 0.15). Furthermore, there was no significant association between ERAS score and surgical technique or case volume., Conclusions: The perioperative management of fetal spina bifida surgery is highly variable across fetal therapy centers worldwide. Standardized protocols integrating ERAS principles may improve patient recovery, reduce maternal morbidity and shorten the hospital stay after fetal spina bifida surgery. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology., (© 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.)

Purpose: While regional anesthesia (RA) is considered preferable to general anesthesia (GA) for Cesarean delivery (CD), certain situations necessitate GA. This study reviewed the practice patterns around the use of GA for CD to identify modifiable predictors of GA with the goal of reducing GA rates., Methods: This was a retrospective, case-control study. Patients undergoing urgent/emergent CD over a 3-year period were identified, from which 102 patients undergoing GA and 102 patients undergoing RA were randomly selected. The data included patient characteristics, obstetrical indications for CD, type/indication of anesthetic, characteristics of airway management (GA group)/neuraxial anesthesia (RA group), and neonatal outcomes., Results: Abnormal fetal heart rate (aFHR) was the most common obstetrical indication for urgent/emergent CD amongst the cases (39%) and controls (39%). GA administration was most commonly due to "limited time due to maternal/fetal compromise" (56%), followed by "maternal contraindication to RA" (25%) and "inadequate RA" (17%). The most frequent modifiable anesthetic indication for GA was inadequate neuraxial anesthesia (17%). Anesthetic and obstetric predictors for GA included ASA classification [OR 0.11 (0.06-0.21)], emergency code activation [OR 13.55 (1.73-106.40)], failure to progress [OR 0.15 ((0.06-0.36)], labor in a patient scheduled for CD [OR 0.16 (0.05-0.57)], pregnancy-related illness [OR 8.63 (1.06-70.38)], cord/fetal prolapse [14.85(1.90-115.94)], and gestational age (OR 0.86 (0.81-0.92))., Conclusion: Abnormal fetal heart rate, specifically bradycardia, was the most common obstetrical indication of GA for urgent/emergent CD, while inadequate neuraxial anesthesia was the most  modifiable anesthetic indication. Our data suggest aFHR and cord/fetal prolapse as potentially modifiable risk factors for GA in certain situations., (© 2024. The Author(s) under exclusive licence to Japanese Society of Anesthesiologists.)

Purpose: The purpose of our study was to determine the minimum effective dose of oxytocin maintenance infusion required to maintain adequate uterine tone in 90% of patients (ED 90 ) after administration of the initial bolus at elective Cesarean delivery (CD) under spinal anesthesia., Methods: We conducted a prospective, double-blind dose-finding study with biased coin up-down design. Immediately after delivery, a 1-IU oxytocin bolus was administered, followed by a maintenance infusion. The obstetrician assessed the uterine tone by palpation as satisfactory or unsatisfactory. In case of unsatisfactory response, the dose for the next patient was increased by 2 IU·hr -1 . For satisfactory response, the dose for the next patient was either decreased by 2 IU·hr -1 with a probability of 1/9, or remained unchanged. The primary outcome was a satisfactory uterine tone from five minutes after delivery until discharge from postanesthesia care unit. The secondary outcomes were blood loss, need for additional uterotonics, and side effects., Results: We analyzed data for 40 patients. The ED 90 of oxytocin maintenance infusion was 4.5 IU·hr -1 (95% confidence interval, 3.3 to 5.5) based on the isotonic regression estimator. The median [interquartile range] blood loss was 861 [553-1,181] mL; 18% received additional uterotonics, and 38% developed hypotension post delivery., Conclusion: Based on the results of this dose-finding study, we recommend a maintenance infusion rate of 4.5 IU·hr -1 following an oxytocin bolus of 1 IU for adequate uterine tone in pregnant patients undergoing elective CDs. This infusion rate is four-fold lower than that required without an initial bolus., Study Registration: ClinicalTrials.gov ( NCT04946006 ); first submitted 25 June 2021., (© 2024. Canadian Anesthesiologists' Society.)

Purpose: A zone of differential block to cold has been recently documented during labour epidural analgesia, with an upper sensory block level (USBL) and a lower sensory block level (LSBL). We aimed to determine the correlation between USBL and LSBL to cold and pinprick and sensory block level to light touch during labour epidural analgesia., Methods: We conducted a prospective observational study in patients requesting labour epidural analgesia. We placed an epidural catheter at L2/L3 or L3/L4, followed by a programmed intermittent epidural bolus plus patient-controlled epidural analgesia regimen. We assessed the sensory block levels 140 min after administering the loading dose. The primary outcomes were the USBL and LSBL to cold and pinprick and the sensory block level to light touch., Results: We studied 30 patients. The median [interquartile range (IQR)] USBL and LSBL to ice were T7 [T7-T6] and T9 [T10-T8], respectively. The median [IQR] USBL and LSBL to pinprick were T8 [T10-T6] and T10 [T12-T10], respectively. There was a strong correlation between USBL to ice and pinprick (Spearman correlation coefficient, 0.57) and between LSBL to ice and pinprick (Spearman correlation coefficient, 0.52). There was no significant correlation between sensory block level to light touch and either USBL or LSBL to ice or pinprick., Conclusion: We observed two sensory block levels to ice and pinprick. Further studies are required to understand if one modality-cold or pinprick-is superior to the other in assessing sensory block levels in this context. Light touch is unreliable as a modality of sensory block assessment during labour epidural analgesia., Trial Registration: ClinicalTrials.gov (NCT05187962); registered 12 January 2022., (© 2023. Canadian Anesthesiologists' Society.)

Background: Multiple pregnancy is associated with higher risk of uterine atony, postpartum hemorrhage (PPH), blood transfusion, hysterectomy, and death. The optimal dose of oxytocin at cesarean delivery in people with twin pregnancy is unknown. We sought to determine the effective bolus dose of oxytocin required to initiate adequate uterine tone in 90% of people (ED90) with twin pregnancy undergoing elective cesarean delivery. Our hypothesis was that the dose of oxytocin would be higher than 0.5 international units (IU) but lower than 5 IU., Methods: A double-blind dose-finding study using the biased coin up-down method was undertaken in people with twin pregnancy ≥36 weeks gestational age undergoing elective cesarean delivery under neuraxial anesthesia. Those with additional risk factors for PPH, apart from twin pregnancy, were excluded. Oxytocin was administered as an intravenous bolus over 1 minute on delivery of the second fetus. The first patient received 0.5 IU, and subsequent oxytocin doses were administered according to a sequential allocation scheme. The actual doses administered were 0.5, 1, 2, 3, 4, and 5 IU of oxytocin. The primary outcome was the response defined as the satisfactory uterine tone at 2 minutes after completion of administration of the oxytocin bolus, as assessed by the operating obstetrician. Secondary outcomes included need for rescue uterotonic drugs, adverse effects, and estimated blood loss. The ED90 was estimated using the Dixon-Mood and the isotonic regression methods., Results: Thirty patients were included in study. The estimated ED90 of oxytocin was 4.38 IU (95% confidence interval [CI], 3.68-4.86 IU) and 3.41 IU (95% CI, 2.83-3.98 IU) by the isotonic regression and Dixon-Mood methods, respectively. Seven patients had inadequate tone at the 2-minute evaluation point and required rescue uterotonic drugs. The median (interquartile range [IQR]) estimated blood loss was 1031 mL (732-1462 mL) calculated by the change in 24-hour hematocrit. Incidence of hypotension after oxytocin administration was 27%, nausea 30%, and vomiting 17%., Conclusions: Our results demonstrated that people with twin pregnancy require a much higher dose of oxytocin than those with singleton pregnancies. We recommended people with twin pregnancies should receive an initial 5 IU bolus over at least 1 minute when undergoing elective cesarean delivery under neuraxial anesthesia., Competing Interests: Conflicts of Interest: See Disclosures at the end of the article., (Copyright © 2022 International Anesthesia Research Society.)

Purpose: The preferred neuraxial anesthetic technique for patients with class 3 obesity undergoing elective Cesarean delivery is still under debate. We aimed to describe the anesthetic technique used in our tertiary institution across body mass index (BMI) groups and different surgical incisions., Method: In this historical cohort study, we reviewed medical records of patients with a BMI ≥ 40 kg·m -2 undergoing elective Cesarean delivery between July 2014 and December 2020. We collected data on patient characteristics, anesthetic and surgical technique, and procedural times. For data analysis, we stratified patients by BMI into three different groups: 40.0-49.9 kg·m -2 , 50.0-59.9 kg·m -2 , and ≥ 60.0 kg·m -2 ., Results: We included 396 deliveries, distributed as follows: 258 with a BMI 40.0-49.9 kg·m -2 , 112 with a BMI 50.0-59.9 kg·m -2 , and 26 with a BMI ≥ 60.0 kg·m -2 . For patients with a BMI 40.0-49.9 kg·m -2 , the anesthetic technique of first choice was predominantly spinal anesthesia (71%), whereas for those with a BMI ≥ 60.0 kg·m -2 , spinal anesthesia was never used as the anesthetic of first choice. With regard to the surgical incision, spinal anesthesia was almost exclusively used for patients undergoing Pfannenstiel incision and was rarely used for a higher supra- or infraumbilical transverse or midline incision. The overall incidence of general anesthesia was low (7/396, 1.8%). Anesthetic time, surgical time, and operating room time increased almost twofold in patients with a BMI ≥ 60.0 kg·m -2 compared with those with a BMI of 40.0-49.9 kg·m -2 ., Conclusion: Neuraxial anesthesia was successfully used in approximately 98% of patients with class 3 obesity undergoing elective Cesarean delivery. The choice of regional anesthesia technique varied with increasing BMI and with the planned surgical incision. Procedural times increased with increasing BMI. This information should prove useful for comparing anesthetic choices and outcomes in this challenging population., (© 2022. The Author(s).)

Purpose: In the context of a programmed intermittent epidural bolus (PIEB) regimen for labour analgesia, one can identify an upper sensory block level (USBL), defined as the highest dermatome with any altered sensation to cold, and a lower sensory block level (LSBL), defined as the highest dermatome with complete sensory block to cold. This study investigated whether and how these sensory block levels vary within PIEB cycles., Methods: We enrolled patients requesting epidural analgesia. An epidural catheter was placed at L2/L3 or L3/L4. A test dose of 3 mL of bupivacaine 0.125% with fentanyl 3.3 µg·mL -1 was administered, followed by 12 mL of the same solution as the loading dose. A PIEB plus patient-controlled epidural analgesia (PCEA) regimen was initiated 40 min after the loading dose, with bupivacaine 0.0625% with fentanyl 2 µg·mL -1 : PIEB 10 mL, PIEB interval 40 min, PCEA 5 mL, lockout interval 10 min, maximum hourly 30 mL. As per institutional protocol, sensory block levels to ice were assessed 20 min after the loading dose and then hourly. Patients included in the study underwent eight extra assessments: immediately before the second and fourth PIEB and 10, 20, and 30 min after the second and third PIEB., Results: We studied 30 patients. The USBL and LSBL achieved their peak value 100 min after the loading dose. The median [interquartile range] USBL was T 8 [T 9 -T 7 ] and T 6 [T 7 -T 4 ] 20 and 100 min after the loading dose, respectively; LSBL was T 10 [T 11 -T 6 ] and T 8 [T 9 -T 6 ], respectively. There was no significant variation in USBL or LSBL within the PIEB cycle between the second and the third or the third and the fourth PIEB., Conclusion: Once peak sensory block levels are established, there is no significant variation in the USBL and LSBL within the PIEB cycles., Study Registration: www., Clinicaltrials: gov (NCT04716660); registered 21 January 2021., (© 2022. Canadian Anesthesiologists' Society.)

Background: Ultrasound is commonly used to facilitate epidural catheter placement. However, data are lacking regarding its potential to confirm its position in the epidural space. Our aim was to visualize flow in the epidural space of patients receiving epidural analgesia for labor using color flow Doppler ultrasound., Methods: We conducted a prospective observational cohort study that included patients who had delivered vaginally under epidural analgesia. We used a 5-2 mHz curvilinear probe in a left and right paramedian longitudinal oblique view to visualize the anterior and posterior complex at the interspace of epidural catheter insertion, one and two interspaces above and below. At each window, the color flow Doppler function was used to visualize flow within the epidural space on injection of normal saline (1 mL). If no flow was visualized at any interspace, one assessment at the level of insertion was repeated with a 1 mL air/saline mixture. We studied a convenience sample size of 40 patients., Results: We visualized flow in the epidural space in all 40 patients. Flow was visualized on injection of 1 mL of saline in 37/40 patients (93%). In the remaining 3/40 patients (7%), flow was visualized with an air/saline mixture. Flow on injection of saline was visualized only at the interspace of insertion in 26/37 patients (70%), at the interspace of insertion and one interspace above in 10/37 (27%), or only at one interspace above in 1/37 (3%). Flow was visualized only on the left or on the right paramedian view in 19/37 patients (51%), despite a symmetrical sensory block in all patients., Conclusion: Color flow Doppler ultrasound is a feasible and fast way to determine flow in the epidural space in the obstetric population. Its potential clinical uses are confirmation of the epidural catheter position after placement, as well as troubleshooting of unsatisfactory epidural analgesia. Interestingly, our results suggest that epidural catheters predominantly remain at the interspace of insertion., Trial Registration Number: NCT05126745., Competing Interests: Competing interests: None declared., (© American Society of Regional Anesthesia & Pain Medicine 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Carbetocin or oxytocin are given routinely as first-line uterotonic drugs following delivery of the neonate during caesarean delivery to prevent postpartum haemorrhage. Low doses may be as effective as high doses with a potential reduction in adverse effects. In this double-blind, randomised, controlled, non-inferiority trial, we assigned low-risk patients undergoing elective caesarean delivery under spinal anaesthesia to one of four groups: carbetocin 20 μg; carbetocin 100 μg; oxytocin 0.5 IU bolus + infusion; and oxytocin 5 IU bolus + infusion. The study drug was given intravenously after delivery of the neonate. Uterine tone was assessed by the obstetrician 2, 5 and 10 minutes after study drug administration according to an 11-point verbal numerical rating scale (0 = atonic, 10 = excellent tone). The primary outcome measure was uterine tone 2 min after study drug administration. The pre-specified non-inferiority margin was 1.2 points on the 11-point scale. Secondary outcomes included uterine tone after 5 and 10 minutes, use of additional uterotonics, blood loss and adverse effects. Data were available for 277 patients. Carbetocin 20 μg resulting in uterine tone of (median (IQR [range])) 8 (7-8 [1-10]) was non-inferior to carbetocin 100 μg with tone 8 (7-9 [3-10]), median (95%CI) difference 0 (-0.44-0.44). Similarly, oxytocin 0.5 IU with tone 7 (6-8 [3-10]) was non-inferior to oxytocin 5 IU with tone 8 (6-8 [2-10]), median (95%CI) difference 1 (0.11-1.89). Carbetocin 20 μg was also non-inferior to oxytocin 5 IU, and oxytocin 0.5 IU was non-inferior to carbetocin 100 μg. Uterine tone after 5 and 10 minutes, use of additional uterotonics, blood loss and adverse effects were similar in all groups., (© 2022 Association of Anaesthetists.)

Competing Interests: The authors declare that they have no conflicts of interest.

Introduction: Epidural analgesia is the preferred method to manage pain during labor and delivery. The insertion of the epidural catheter can be complicated by unintentional dural puncture that may result in postdural puncture headache. There is limited evidence on the long-term implications of this complication. We sought to investigate if women who sustained a dural puncture have a higher risk of developing chronic headache, low back pain and visual or auditory impairment., Methods: We conducted a 1:1 case-control study with women who delivered at our institution from January 2015 to December 2019. Cases were women who received epidural analgesia and sustained an unintentional dural puncture, and controls were women who received epidural analgesia but did not sustain such complication. We matched cases and controls for date of delivery, age, and body mass index. All women completed an online survey with validated questionnaires for diagnosis of chronic headache and chronic back pain. We used dichotomic (yes/no) questions to look for the presence of chronic visual and auditory impairment., Results: Sixty-three case-control pairs were studied. Women who sustained a dural puncture during their epidural catheter insertion had a higher risk of developing chronic headache (14.3%, vs 4.8%, p=0.057, adjusted OR (AOR): 3.67 (95% CI 1.05 to 12.82)) and chronic back pain (39.7% vs 19.1%, p=0.009, AOR: 2.67 (95% CI 1.25 to 5.72)) than women who did not sustain a dural puncture. The incidence of chronic auditory impairment was also higher in the dural puncture group (14.3% vs 1.6%, p=0.01, AOR: 9.98 (95% CI 1.21 to 82.62))., Conclusions: An unintentional dural puncture during epidural catheter insertion in parturients is associated with increased risk of chronic headache, back pain and auditory impairment., Competing Interests: Competing interests: None declared., (© American Society of Regional Anesthesia & Pain Medicine 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: Assessment of sensory block level during labour epidural analgesia is an essential component of clinical practice and patient safety. Nevertheless, the methods and direction of testing are not standardized. In our hospital, sensory block testing to ice is routinely used, but while some anesthesiologists test the block from a nonanesthetized to an anesthetized area, some do it in the opposite direction. It is unknown how these two different practices affect identification of the sensory block level. The objective of this study was to determine the agreement between these two practices., Methods: We enrolled 31 patients admitted to the labour and delivery unit in a prospective cohort study. At their request, labour epidural analgesia was performed as per institutional routine. Sensory block level to ice was assessed using opposite directions by two randomly assigned independent investigators, one and two hours after the loading dose was administered., Results: Sensory block levels to ice assessed from an anesthetized area to a nonanesthetized area were lower than those when assessed with the stimulus applied in the opposite direction, typically one segment lower., Discussion: Given the small difference detected with both methods, it may be acceptable to use either in clinical practice. Nevertheless, the lack of standardization may have a significant impact when comparing studies involving assessment of sensory block to ice., Study Registration: www., Clinicaltrials: gov (NCT03572439); registered 28 June 2018., (© 2022. Canadian Anesthesiologists' Society.)

Objective: To describe the evolution and evaluation of protocol-based multidisciplinary quality improvement (QI) in women undergoing cesarean hysterectomy for radiologically suspected and pathologically confirmed placenta accreta spectrum (PAS) disorders., Methods: A single-center, retrospective cohort study was conducted of all patients undergoing cesarean hysterectomy for PAS disorders between March 2009 and June 2018. Two distinct periods were defined to compare outcomes: 2009-2011 (initial period) and 2017-2018 (current period). Primary outcomes included blood loss and administration of blood products. Secondary outcomes included perioperative levels of hemoglobin, adverse events and complications, time to mobilization, and length of hospitalization., Results: Among the 105 consecutive patients identified, there were 26 in the initial period and 32 in the current period. With the implementation of all QI care bundles, median estimated surgical blood loss halved from 2000 ml in the initial period to 1000 ml in the current period, and fewer patients required allogenic blood transfusion (61.5% vs 25%). Patients in the current period demonstrated improved postoperative levels of hemoglobin compared to those in the initial period (101 g/L vs 89 g/L) and had a shorter median postoperative hospital stay (3 days vs 5 days)., Conclusion: These results support the implementation of a multifaceted QI and patient care initiative for women with PAS disorders., (© 2021 International Federation of Gynecology and Obstetrics.)

Purpose: A nationwide shortage of oxytocin in Canada resulted in a temporary switch from oxytocin to carbetocin for all postpartum women at our institution. This change offered a unique opportunity to conduct a pragmatic comparative assessment of the efficacy of carbetocin and oxytocin., Methods: In a retrospective before-after study, we reviewed the medical records from 641 women in the carbetocin group and 752 women in the oxytocin group . The standard carbetocin dosing was 100 µg iv following vaginal and intrapartum Cesarean delivery, while for elective Cesarean delivery it was 50 µg, with an additional 50 µg if required. The standard oxytocin dosing was 5 IU iv followed by 2.4 IU·hr -1 for four to six hours after vaginal delivery, while for Cesarean delivery it was 1-3 IU iv, three minutes apart, up to 10 IU if required, followed by the same maintenance. In both modalities of delivery, if uterine tone was suboptimal, the maintenance dose of oxytocin could be increased to 4.8 IU·hr -1 . In both groups, additional uterotonics were used as required. The primary outcome was the need for additional uterotonics. Secondary outcomes included estimated and calculated blood loss, the occurrence of postpartum hemorrhage, and the need for blood transfusion., Results: The incidence of additional uterotonic use was not different between the carbetocin and oxytocin groups (12.0% vs 8.8%; P = 0.05; odds ratio, 1.39; 95% confidence interval, 0.97 to 2.00). The incidence of postpartum hemorrhage was higher in the carbetocin group than in the oxytocin group (10.3% vs 6.6%; P = 0.01). Blood transfusion was more common in the carbetocin group (1.4% vs 0.3%; P = 0.02)., Conclusion: There was no difference in the use of additional uterotonics when carbetocin or oxytocin were used in a cohort of women undergoing vaginal deliveries and both elective and emergency Cesarean deliveries., (© 2021. Canadian Anesthesiologists' Society.)

Purpose: Programmed intermittent epidural bolus (PIEB) provides better analgesia for labour pain than continuous epidural infusion does. Nevertheless, commonly used PIEB regimens are associated with high sensory block. We hypothesized that a PIEB technique with slower bolus delivery speed would produce lower sensory levels., Methods: We recruited term nulliparous women with singleton pregnancies during the first stage of labour. All participants had an American Society of Anesthesiologists Physical Status score of II-III, had epidural catheters placed at L3/4, and had epidural analgesia maintained with PIEB 10 mL every 40 min using 0.0625% bupivacaine with fentanyl 2 µg·mL -1 . Women were randomized to receive PIEB delivered at 250 mL·hr -1 (G250) or 125 mL·hr -1 (G125). The study was completed six hours after the loading dose or at full cervical dilatation, whichever occurred first. The primary outcome was the presence of sensory block to ice ≥ T6 in at least one assessment during the study period (maximum six hours)., Results: We analyzed data from 90 women. The proportion of women presenting sensory block ≥ T6 at any time was not different between G125 and G250 groups (60.0% vs 64.4%; difference, -4.4%; 95% confidence interval [CI], -24.5 to 15.6; P = 0.66). The median [interquartile range] highest sensory block level was also not different between G125 and G250 groups (T6 [T7-T5] vs T5 [T7-T5], P = 0.39). Women in the G125 group had a lower incidence of hypotension than women in the G250 group did (11.1% vs 33.3%; difference, -22.2%; 95% CI, -38.8 to -5.67; P = 0.01). Quality of analgesia and patient satisfaction were not different between groups., Conclusion: The maintenance of epidural analgesia with a PIEB delivery speed of 125 mL·hr -1 did not produce lower sensory block levels when compared with 250 mL·hr -1 . The slower injection speed regimen was associated with lower incidence of hypotension, but this secondary finding warrants confirmation in a future trial., Trial Registration: www.ClinicalTrials.gov (NCT03236298); registered 1 August 2017., (© 2021. Canadian Anesthesiologists' Society.)

Purpose: Approximately one in five women will experience severe postoperative pain after Cesarean delivery (CD). Previously, a bedside three-item questionnaire (3-IQ) has shown to predict women experiencing higher evoked pain intensity after CD, with an area under the receiver operator characteristics (ROC) curve of 0.72. We hypothesized that the addition of psychophysical pain tests to the existing 3-IQ would improve the ability to predict severe pain in women undergoing elective CD under spinal anesthesia METHODS: This was a prospective cohort study on women undergoing elective CD under spinal anesthesia. Women were assessed preoperatively using the 3-IQ, pressure algometry (PA) and mechanical temporal summation (TS) response. All women received standard perioperative care, including a multimodal analgesia regimen that included intrathecal fentanyl and morphine. A 0-100 mm visual analogue scale (VAS) was used to assess the severity of pain at rest (VASr) and on movement (VASm) at 24 and 48 hr after surgery. Patient satisfaction and opioid consumption were also recorded. We performed ROC curve analyses to assess whether we could improve the ability to predict our primary outcome of severe pain on movement at 24 hr (VASm24 ≥ 70)., Results: We studied 195 women. Median [interquartile range] VASm24 was 53 [32-72] and 28% of patients experienced a VASm24 ≥ 70. The ability to predict a VASm24 ≥ 70 assessed by the area under the ROC curve was 0.64 using the 3-IQ and 0.67 using the 3-IQ combined with TS and PA., Conclusion: The addition of PA and TS to the 3-IQ model resulted in a predictive model that performed similarly to the 3-IQ model alone. Further research is warranted in this area to better predict women at risk of severe pain post CD., (© 2021. Canadian Anesthesiologists' Society.)

Competing Interests: The authors declare that they have no conflict of interest.

Background: Ultrasound assistance improves success rates and reduces adverse outcomes of lumbar punctures (LPs) among adult patients in the emergency room and the operating room, but has not been evaluated in pediatric patients with cancer. Our objectives were (1) to determine whether pediatric oncologists could perform ultrasound-assisted LPs following a structured teaching curriculum, and (2) to determine the feasibility of recruiting pediatric cancer patients to a clinical trial of this procedure., Methods: Three pediatric oncologists completed a curriculum composed of didactic teaching followed by hands-on workshops. Each learner was evaluated during 20 attempts at three ultrasound tasks using the cumulative sum method. The three pediatric oncologists then performed ultrasound assessments prior to routinely scheduled LPs. Feasibility was defined as ability to perform at least 30 ultrasound-assisted LPs within 6 months. Secondary outcomes were the proportion of successful, bloody, or traumatic LPs, time required, and perceived helpfulness of ultrasound., Results: All three pediatric oncologists achieved competence in the three tasks of ultrasound scanning within 20 evaluated attempts. We recruited 62 patients within 1 month, and 58 underwent an ultrasound-assisted LP. All LPs were successful. Two LPs (4%) had ≥500 red blood cells (RBCs)/μl, and nine (16%) had ≥10 RBCs/μl. Median time to conduct the scan was 1.9 minutes (range 0.8-4.0 minutes). In 37 (64%) of the LPs, ultrasound assistance was considered helpful or very helpful., Conclusions: Pediatric oncologists readily achieved competence in ultrasound-assisted LPs, and ultrasound was commonly perceived as helpful. It is feasible to proceed to a randomized trial of this procedure in pediatric cancer., (© 2021 Wiley Periodicals LLC.)

Prophylactic oxytocin administration at the third stage of labour reduces blood loss and the need for additional uterotonic drugs. Obesity is known to be associated with an increased risk of uterine atony and postpartum haemorrhage. It is unknown whether women with obesity require higher doses of oxytocin in order to achieve adequate uterine tone after delivery. The purpose of this study was to establish the bolus dose of oxytocin required to initiate effective uterine contraction in 90% of women with obesity (the ED 90 ) at elective caesarean delivery. We conducted a double-blind dose-finding study using the biased coin up-down design method. Term pregnant women with a BMI ≥ 40 kg.m -2 undergoing elective caesarean delivery under regional anaesthesia were included. Those with conditions predisposing to postpartum haemorrhage were not included. Oxytocin was administered as an intravenous bolus over 1 minute upon delivery of the fetus. With the first woman receiving 0.5 IU, oxytocin doses were administered according to a sequential allocation scheme. The primary outcome measure was satisfactory uterine tone, as assessed by the operating obstetrician 2 minutes after administration of the oxytocin bolus. Secondary outcomes included the need for rescue uterotonic drugs, adverse effects and estimated blood loss. We studied 30 women with a mean (SD) BMI of 52.3 (7.6) kg.m -2 . The ED 90 for oxytocin was 0.75 IU (95%CI 0.5-0.93 IU) by isotonic regression and 0.78 IU (95%CI 0.68-0.88 IU) by the Dixon and Mood method. Our results suggest that women with a BMI ≥ 40 kg.m -2 require approximately twice as much oxytocin as those with a BMI < 40 kg.m -2 , in whom an ED 90 of 0.35 IU (95%CI 0.15-0.52 IU) has previously been demonstrated., (© 2020 Association of Anaesthetists.)

Objective: Fetal myelomeningocele closure results in better infant outcomes than postnatal closure at the cost of potential prematurity and maternal morbidity. Our aim is to describe the setup of a fetal myelomeningocele closure program in Canada and document its outcomes., Methods: We conducted a retrospective review of all open fetal myelomeningocele closure surgeries performed at the Ontario Fetal Centre in its first 3 years of operation (2017-2020). Maternal and fetal baseline characteristics, surgical details, pregnancy outcomes, and infant follow-up until 1 year of age were recorded., Results: Twenty-seven women underwent fetal myelomeningocele closure surgery, 10 of whom (37%) resided outside of Ontario. Mean gestational age at surgery was 25.0 ± 0.7 weeks. All surgeries were technically uncomplicated and no fetal deaths occurred. There was a significant negative correlation between increasing experience and skin-to-skin surgical time (R² = 0.36; P = 0.001). Of the 26 patients who have delivered, 4 (15.4%) experienced preterm prelabour rupture of membranes. Mean gestational age at delivery was 34.9±3.0 weeks. All but 1 patient delivered by cesarean. Maternal complications occurred in 9 women (34.6%). There were no maternal deaths, but 3 (11.5%) infant deaths. Of the 14 surviving infants who have reached at least 1 year of age, 5 (35.7%) underwent ventriculo-peritoneal shunting. Of the 9 infants who have not yet reached 1 year of age, 3 (33.3%) underwent endoscopic third ventriculostomy and none underwent shunting., Conclusion: Fetal open spina bifida closure can be performed in Canada, with results similar to those reported by other international expert centres. Long-term follow-up is ongoing., (Copyright © 2020 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.)

Purpose: We studied the programmed intermittent epidural bolus (PIEB) time interval between boluses of 2.5 mL of bupivacaine 0.25% with fentanyl 8 µg·mL -1 to produce effective analgesia in 90% of women (EI90) during the first stage of labour., Methods: In a double-blind sequential allocation trial using a biased coin up-and-down design to determine the EI90, the PIEB boluses of 2.5 mL of 0.25% bupivacaine plus fentanyl 8 µg·mL -1 were delivered at varying intervals-60, 50, 40, and 30 min. The primary outcome was the adequate response of the patient to the PIEB regimen, defined as no use of supplemental analgesia for six hours or until the first stage of labour was completed, whichever came first. The secondary outcomes were the upper sensory block level to ice, motor block and hypotension. The isotonic regression with extrapolation approach was used to estimate the EI90., Results: In the 20 women studied, the estimated EI90 was 20 (95% CI, 5.9 to 28.8) min. For the secondary outcomes, we classified women into those assigned to 30 min (16 women) and those assigned to more than 30 min (four women). The median upper sensory block for women in the 30-min group and more than 30 min were T6 (or T5) and T7, respectively. No participants experienced motor block. Hypotension occurred in one patient in the 30-min group., Conclusion: The estimated EI90 for boluses of 2.5 mL of bupivacaine 0.25% with fentanyl 8 µg·mL -1 was 20 (95% CI, 5.9 to 28.8) min. These results suggest that there is no advantage in using this regimen compared with those reported in the literature using the same dose of bupivacaine in concentrations of 0.0625% and 0.125%., Trial Registration: www.clinicaltrials.gov (NCT03735771); registered 7 November 2018.

Objective: To evaluate whether prophylactic administration of oxytocin plus ergonovine or oxytocin plus carboprost is more effective than oxytocin alone in reducing the need for additional uterotonics among women undergoing cesarean delivery for labor arrest., Methods: In this double-blind, three-arm randomized controlled trial, participants were assigned to receive either oxytocin 5 units intravenous alone, or with ergonovine 0.25 mg intravenous or carboprost 0.25 mg intramuscular immediately after delivery, followed with maintenance infusion of oxytocin 40 milliunits/minute in all groups. Uterine tone was assessed at 3, 5, and 10 minutes after delivery, and additional uterotonics were administered if deemed necessary. The primary outcome was intraoperative need for additional uterotonics. Secondary outcomes included uterine tone, calculated blood loss, and side effects. A sample size of 34 per group (n=102), based on the null hypothesis that there is no association between treatment assignment and the need for additional uterotonics, permitted independent post hoc pairwise comparisons between oxytocin plus ergonovine, oxytocin plus carboprost, and oxytocin alone using an adjusted P-value of .025. The association between the need for additional uterotonics and treatment group was assessed using the χ2 test., Results: From June 2013 through July 2019, 105 participants were randomized (35 per group) and data from 100 participants were analyzed: oxytocin (n=35), oxytocin plus ergonovine (n=33), and oxytocin plus carboprost (n=32). There was no difference in the requirement of additional intraoperative uterotonics across groups (oxytocin [37%] vs oxytocin plus ergonovine [33%] vs oxytocin plus carboprost [34%], P=.932). Uterine tone and calculated blood loss were similar across groups. Incidence of nausea or vomiting was higher in oxytocin plus ergonovine (85%; odds ratio [OR] 5.3, 95% CI 1.7-16.9, P=.003) and oxytocin plus carboprost (72%; OR 2.4, 95% CI 0.9-6.7, P=.086) compared with the oxytocin (51%) group., Conclusion: Compared with oxytocin alone, prophylactic use of a combination of uterotonic drugs did not reduce the need for additional uterotonics at cesarean delivery for labor arrest., Clinical Trial Registration: ClinicalTrials.gov, NCT01869556., Competing Interests: Financial Disclosure The author did not report any potential conflicts of interest., (Copyright © 2021 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Shock index and continuous non-invasive haemoglobin monitoring (SpHb) have both been proposed for the timely recognition of postpartum haemorrhage (PPH). We sought to determine, in parallel, the association of each of shock index and SpHb with blood loss after vaginal delivery., Methods: Sixty-six women were recruited to this prospective observational study. Shock index and SpHb were recorded postpartum for 120 min. The association between each of shock index and SpHb with quantitative blood loss (QBL) at 30, 60 and 120 min postpartum was determined using linear mixed models. Area-under-the-receiver-operator-characteristic (AUROC) curves were constructed to evaluate the diagnostic ability of shock index and SpHb to detect PPH (defined as QBL ≥1000 mL)., Results: Shock index trend was associated with QBL over the first 30 min (r=0.37, P=0.002), but not over 60 or 120 min. There was an association of SpHb trend with QBL over the first 30 min (P=0.06), but not over 60 min (r=-0.32, P=0.009) or 120 min (r=-0.26, P=0.03). Maximum shock index within 60 min correlated with QBL (r=0.54, P <0.001) and was a predictor of PPH (P=0.0012, AUROC 0.796). Maximum change in SpHb within 60 min negatively correlated with QBL (r=-0.4, P <0.001) and was a predictor of PPH (P=0.048, AUROC 0.761)., Conclusions: The trend of shock index and its peak values are associated with blood loss after vaginal delivery and are early indicators of PPH. Negative trend of SpHb is a late sign of PPH and has a weaker association with blood loss than shock index., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Introduction: We wanted to better understand the quality of our labor epidural practice at a large urban academic medical center. Several practice changes were implemented between 2011 and 2017, namely a more uniform epidural loading dose of local anesthetic that includes fentanyl, an increase in both the hourly baseline offer and maximum allowed hourly amount of bupivacaine, and the change from a continuous epidural infusion to a programmed intermittent epidural bolus (PIEB) regimen. We aimed to assess the impact of those changes on the quality of labor analgesia., Methods: We performed two separate audits representing before-and-after groups. The audits were performed in November 2011 (before group) and November-December 2017 (after group). The data for 2011 were extracted from a previously published study. Hence, we conducted a similar audit in 2017, including only outcomes that were included in the previous audit. The primary outcome was the presence of pain >3 (Numerical Rating Scale 0-10) at any time during first or second stage of labor. Secondary outcomes included top-up requirements, and women's pain perception during the first and second stage of labor according to a postpartum questionnaire., Results: We studied 294 and 247 women in the before-and-after groups, respectively. The proportion of women reporting pain >3/10 at any time during labor and delivery significantly decreased in the after group (30% vs 41%; p<0.01). In an adjusted analysis, there was a 35% reduction in the likelihood of pain scores>3 for the after group (OR 0.65, 95% CI 0.46, 0.94). Women in the after group received fewer top-ups by nurses (3% vs 24%, p<0.001). Most women in both cohorts (85% before and 87% after) were satisfied with the overall quality of analgesia., Discussion: A bundle of practice changes implemented in our clinical practice, including the PIEB regimen, has resulted in a significant improvement in the quality of labor analgesia. However, despite all the implemented changes, 30% of women still experience pain during labor and further optimization of our practice is warranted., Competing Interests: Competing interests: None declared., (© American Society of Regional Anesthesia & Pain Medicine 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Nitroglycerin is used for acute reduction in uterine tone. Prolonged oxytocin exposure causes desensitization of oxytocin receptors. It is unknown if nitroglycerin exposure impacts the subsequent action of oxytocin in the setting of oxytocin receptor desensitization. This study investigated the effects of nitroglycerin on oxytocin-desensitized and oxytocin-naïve human myometrium and the subsequent response to oxytocin dose-response testing in vitro., Methods: Myometrial samples from 17 elective cesarean deliveries were divided into strips and allocated to 1 of 4 groups: (1) oxytocin desensitized and no nitroglycerin; (2) oxytocin desensitized and nitroglycerin; (3) oxytocin naïve and nitroglycerin; and (4) oxytocin naïve and no nitroglycerin. Final analysis included 28 strips per group. Nitroglycerin groups were exposed to incremental concentrations of nitroglycerin, while no nitroglycerin groups were kept in control (physiological salt) solution. All groups then underwent oxytocin dose-response testing. Primary outcome was motility index (amplitude × frequency; grams × contractions per 10 minutes [g·c/10 min]). Secondary outcomes were amplitude (g), frequency (contractions/10 minutes), and area under the curve (g·s). All outcomes (nitroglycerin and oxytocin dose-response periods) were expressed as a percentage change from baseline. Values were log transformed, compared using regression modeling and reported as the ratio of 2 geometric means (relative difference)., Results: No significant difference was observed in motility index following nitroglycerin administration in oxytocin-desensitized versus oxytocin-naïve groups (relative difference = 19.0%; 95% confidence interval [CI], -32.6 to 109.9; P = .55). On oxytocin dose-response testing, motility index was highest in oxytocin-naïve and no nitroglycerin samples (group 4) (1.356 g·c/10 minutes) followed by oxytocin-naïve and nitroglycerin (group 3) (0.882 g·c/10 minutes), oxytocin-desensitized and no nitroglycerin (group 1) (0.769 g·c/10 minutes), and oxytocin-desensitized and nitroglycerin (group 2) (0.651 g·c/10 minutes) samples. Motility index was significantly reduced in group 1 vs 4 (relative difference = -43.3%; 95% CI, -66.5 to -4.1; P = .034) and group 2 vs 4 (relative difference = -52.0%; 95% CI, -70.9 to -20.8; P = .004). While in groups 3 vs 4, both amplitude (relative difference = -17.8%; 95% CI, -30.9 to -2.2; P = .27) and area under the curve (AUC; relative difference = -17.5%; 95% CI, -30.7 to -1.8; P = .030) were reduced., Conclusions: Nitroglycerin-induced relaxation was not different between oxytocin-desensitized and oxytocin-naïve human myometrial strips in vitro. However, oxytocin-induced contractility was attenuated after nitroglycerin exposure in both oxytocin-desensitized and oxytocin-naïve samples, with maximum attenuation observed in desensitized tissues. This finding warrants further clinical studies to explore uterine responsiveness to oxytocin in women with oxytocin-augmented labors after nitroglycerin administration.

Worldwide, about 150 000 infants are born with spina bifida yearly, making this condition one of the most common fetal central nervous system anomalies compatible with life. Over the last decade, major changes have been introduced in the prenatal diagnosis and management of spina bifida. In this review, we provide a brief summary of the current management of fetal spina bifida and present essential information that should be provided to expecting parents when their fetus has been diagnosed with spina bifida. This information is focused around common parental questions, as encountered in our typical clinical practice, to facilitate knowledge translation., (© 2020 John Wiley & Sons Ltd.)

Background: Open spina bifida (OSB) is one of the most common congenital central nervous system defects and leads to long-term physical and cognitive disabilities. Open fetal surgery for OSB improves neurological outcomes and reduces the need for ventriculoperitoneal shunting, compared to postnatal surgery, but is associated with a significant risk of prematurity and maternal morbidity. Fetoscopic surgery comes with less maternal morbidity, yet the question remains whether the procedure is neuroprotective and reduces prematurity. Comparison of outcomes between different treatment options is challenging due to inconsistent outcome reporting. We aim to develop and disseminate a core outcome set (COS) for fetal OSB, to ensure that outcomes relevant to all stakeholders are collected and reported in a standardised fashion in future studies., Methods: The COS will be developed using a validated Delphi methodology. A systematic literature review will be performed to identify outcomes previously reported for prenatally diagnosed OSB. We will assess maternal (primary and subsequent pregnancies), fetal, neonatal and childhood outcomes until adolescence. In a second phase, we will conduct semi-structured interviews with stakeholders, to ensure representation of additional relevant outcomes that may not have been reported in the literature. We will include patients and parents, as well as health professionals involved in the care of these pregnancies and children (fetal medicine specialists, fetal surgeons, neonatologists/paediatricians and allied health). Subsequently, an international group of key stakeholders will rate the importance of the identified outcomes using three sequential online rounds of a modified Delphi Survey. Final agreement on outcomes to be included in the COS, their definition and measurement will be achieved through a face-to-face consensus meeting with all stakeholder groups. Dissemination of the final COS will be ensured through different media and relevant societies., Discussion: Development and implementation of a COS for fetal OSB will ensure consistent outcome reporting in future clinical trials, systematic reviews and clinical practice guidelines. This will lead to higher quality research, better evidence-based clinical practice and ultimately improved maternal, fetal and long-term childhood outcomes., Trial Registration: International Prospective Register of Systematic Reviews (PROSPERO) CRD42018104880 . Registered on December 5, 2018. Core Outcome Measures in Effectiveness Trials (COMET): 1187.

Purpose: The purpose of this study was to investigate myometrial contractility induced by oxytocin in women with advanced maternal age (AMA) and morbid obesity (MO). We hypothesized that both oxytocin-pretreated and oxytocin-naïve myometrial tissues from women of AMA and women who are MO would exhibit poor myometrial contractility compared with women that are younger and of normal body mass index (BMI)., Methods: This prospective in vitro study was conducted using myometrial samples obtained from women undergoing elective Cesarean deliveries. Three groups of patient were studied: control (≤ 35 yr; BMI, 20-24.9 kg·m -2 ), AMA (≥ 40 yr; BMI, 20-24.9 kg·m -2 ), and MO (≤ 35 yr BMI, ≥ 40 kg·m -2 ). Each myometrial strip was either pretreated with oxytocin 10 -5 M or left in physiologic salt solution for two hours. This was followed by a dose-response testing to oxytocin (10 -10 M to 10 -5 M), during which contractile parameters were measured. The primary outcome was motility index (MI, amplitude × frequency) of contractions., Results: The MI of contractions was reduced in oxytocin-pretreated samples when compared with their oxytocin naïve counterparts in control (estimated difference -69%; 95% confidence interval [CI], -82 to -48; P < 0.001) and AMA groups (estimated difference, -44%; 95% CI, -68 to -2; P = 0.07). The MI of contractions was not different between oxytocin naïve and oxytocin-pretreated samples from MO women (estimated difference, -26%; 95% CI, -63 to 49; P = 0.46); however, it was significantly lower in these groups compared with oxytocin-naïve samples from the control group., Conclusions: Oxytocin pre-treatment reduced myometrial contractility in AMA and control group women compared with their oxytocin-naïve counterparts, as a function of the desensitization phenomenon. Attenuated oxytocin-induced myometrial contractility in MO women in both oxytocin-pretreated and oxytocin-naïve samples suggests that these women have intrinsically reduced uterine contractile ability., Trial Registration: www.clinicaltrials.gov (NCT01865669; registered 28 May, 2013).

Postpartum haemorrhage is a leading cause of maternal death during childbirth. There is an increasing incidence of atonic postpartum haemorrhage in developed countries, and maternal obesity has been proposed as a contributing factor. The dose-response relationship of carbetocin in obese women has not yet been determined. We conducted a double-blind, dose-finding study of carbetocin using a biased coin up-and-down design in women with a body mass index ≥ 40 kg.m -2 undergoing elective caesarean section. The determinant for a successful response was satisfactory uterine tone, with no intra-operative need for additional uterotonic drugs. Secondary outcomes included the use of additional uterotonic drugs postoperatively, estimated blood loss and adverse effects of carbetocin administration. Thirty women were recruited to the study. The median (IQR [range]) body mass index was 44.93 (41.5-55.2 [40-66.5]) kg.m -2 . The ED 90 of carbetocin was estimated as 62.9 (95%CI 57.0-68.7) μg using the truncated Dixon and Mood method, and 68 (95%CI 52-77) μg using the isotonic regression method. The estimated blood loss was 880 (621-1178 [75-2442]) ml. The overall rates of hypotension and hypertension after delivery were 40% and 6.7%, respectively, while nausea occurred in 26.7% of women. The ED 90 for carbetocin in obese women at elective caesarean section is lower than the dose of 100 μg currently recommended by the Society of Obstetricians and Gynaecologists of Canada, but is approximately four times higher than the previously demonstrated ED 90 of 14.8 μg in women with body mass index < 40 kg.m -2 ., (© 2019 Association of Anaesthetists.)

Importance: Women giving birth have high rates of dural puncture secondary to neuraxial anesthesia and are at high risk for a resulting headache. It appears to be unknown whether there is a significant association between post-dural puncture headache and subsequent intracranial subdural hematoma., Objective: To determine the association of post-dural puncture headache with postpartum intracranial subdural hematoma., Design, Setting, and Participants: This cohort study of patients used hospital discharges recorded in the US Agency for Healthcare Research and Quality National Readmission Database for women who experienced childbirth from January 2010 to December 2016. Patients were included if they had been admitted for childbirth, had 2 months of follow-up data, and did not receive a diagnostic lumbar puncture. Only the first delivery for a calendar year was studied. Data were analyzed from January 2018 to June 2019., Exposures: Women with post-dural puncture headache associated with neuraxial anesthesia in the 2-month postpartum period were identified using International Classification of Disease (Ninth Edition and Tenth Edition) codes and were compared with those without post-dural puncture headaches., Main Outcome and Measures: The primary outcome was intracranial subdural hematoma in the 2-month postpartum period. Secondary outcomes included in-hospital mortality and occurrence of neurosurgery., Results: A total of 26 469 771 patients with 26 498 194 deliveries were included. Exclusion of repeated deliveries (n = 28 423), deliveries without 2 months of follow-up data (n = 4 329 621), and deliveries with diagnostic lumbar puncture (n = 9334) resulted in a final cohort of 22 130 815 patients and deliveries. For the cohort, the mean (SD) age was 28.1 (6.0) years, and there were 68 374 post-dural puncture headaches, for an overall rate of 309 (95% CI, 302-316) per 100 000. There were 342 cases of subdural hematoma identified, indicating a rate of 1.5 (95% CI, 1.3-1.8) per 100 000 women. Of these, 100 cases were in women with post-dural puncture headache, indicating a rate of 147 (95% CI, 111-194) hematoma cases per 100 000 deliveries in this subgroup. Post-dural puncture headache had an unadjusted absolute risk increase of 145 (95% CI, 117-174) subdural hematoma cases per 100 000 deliveries. After adjusting for confounders, post-dural puncture headache had an odds ratio for subdural hematoma of 199 (95% CI, 126-317; P < .001) and an adjusted absolute risk increase of 130 (95% CI, 90-169; P < .001) per 100 000 deliveries., Conclusions and Relevance: The presence of presumed post-dural puncture headache after neuraxial anesthesia in childbirth, compared with no headache, was associated with a small but statistically significant absolute increase in the risk of being diagnosed with intracranial subdural hematoma. Further research is needed to establish if this association is causal for this rare outcome.

Background: Phenylephrine (PE) is currently the vasopressor of choice to prevent and treat spinal-induced hypotension at cesarean delivery (CD). However, its use is often associated with reflex bradycardia. Norepinephrine (NE) has been put forward as an alternative vasopressor during CD due to its ability to treat hypotension while maintaining heart rate (HR). Recent studies have focused on the role of NE used as an infusion with favorable results compared to PE. No studies have compared equipotent bolus doses of PE and NE at CD. We hypothesized that when used in equipotent doses as an intermittent bolus regimen to prevent and treat spinal-induced hypotension, NE would result in a reduction in the incidence of bradycardia compared to PE., Methods: This was a double-blind, randomized clinical trial of women undergoing elective CD under spinal anesthesia. Women were randomized to receive either PE 100 µg or NE 6 µg when the systolic blood pressure (SBP) was below baseline. In addition to the randomized treatment, ephedrine was given intravenously to both groups if the SBP was below baseline and the HR <60 bpm or if the SBP was <80% of baseline for 2 consecutive readings. The primary outcome was bradycardia (HR <50 bpm) in the predelivery period. Secondary outcomes included hypotension (SBP <80% of baseline), hypertension (SBP >120% of baseline), tachycardia (HR >120% of baseline), ≥2 episodes of bradycardia, nausea, vomiting, umbilical artery and vein blood gases, and Apgar scores., Results: One hundred twelve patients were randomized. The incidence of bradycardia was lower in the NE group compared to the PE group (10.7% vs 37.5%; P < .001; difference [95% confidence interval {CI}], -26.8% [-41.8% to -11.7%]), implying an estimated 71% relative reduction (95% CI, 35%-88%). The distribution of the number of bradycardia episodes was also different between the 2 groups (P = .007). Further testing showed that the patients in the PE group had a higher risk of multiple bradycardia episodes (≥2 episodes) compared to the NE group (19.6% for PE versus 3.6% for NE; P = .008). The proportion of patients requiring rescue boluses of ephedrine was lower in the NE group compared to the PE group (7.2% for NE versus 21.4% for PE; P < .03; difference [95% CI], -14.3% [-27.0% to -1.6%]). No differences were observed between the 2 groups in the incidence of other secondary outcomes., Conclusions: When used as an intermittent bolus regimen to prevent and treat spinal-induced hypotension during CD, NE resulted in a significant reduction in the incidence of bradycardia as compared to an equipotent bolus regimen of PE. We conclude that the hemodynamic profile offered by NE during CD is superior to that of PE due to less fluctuations in HR and possibly cardiac output.

Purpose: Primary immune thrombocytopenia (ITP) is an autoimmune condition affecting women of childbearing age that is characterized by diminished platelet quantity with preserved function. Although pregnant women with ITP are often denied obstetric neuraxial anesthesia (OBNA) with low platelet counts for fear of neuraxial hematoma, the true magnitude of neuraxial hematoma for ITP parturients is unknown. The aim of this systematic review and meta-analysis was to examine OBNA outcomes in ITP parturients with platelet counts below 100 x 10 9 ·L -1 ., Source: Articles published in MEDLINE, Embase, Web of Science, Scopus, Cochrane, and PubMed in process until May 14, 2018 were searched. Two reviewers independently screened 954 articles by title and abstract, reviewed 62 full-texts, extracted data, and assessed risk of bias for 26 articles., Principal Findings: Of 291 pregnant women with ITP and platelet counts below 100 x 10 9 ·L -1 , 166 received OBNA and 61 of these had platelet counts below 80 x 10 9 ·L -1 . No neuraxial hematomas were reported. Meta-analysis of six studies showed higher platelet counts in those with OBNA than without (mean difference [MD], 19 x 10 9 ·L -1 ; 95% confidence interval [CI], 11 to 26; P < 0.001), with no difference between epidural and spinal anesthesia (MD, 0.4 x 10 9 ·L -1 ; 95% CI, -4 to 4; P = 0.86)., Conclusion: Our study highlights continued reluctance to offer OBNA below the commonly quoted 80 x 10 9 ·L -1 platelet count, based largely on consensus and theoretical presumption of risk. This further negatively influences the accrual of large-scale data. The evidence of no neuraxial hematoma after OBNA provided herein offers support for considering neuraxial anesthesia at lower platelet count thresholds. Each patient should be afforded individualized discussion of risk and benefit relative to other analgesic measures., Trial Registration: PROSPERO (CRD42018059220); registered 2 August, 2018.

It is routine to give a uterotonic drug following delivery of the neonate during caesarean section. However, there is much heterogeneity in the relevant research, which has largely been performed in low-risk elective cases or women with uncomplicated labour. This is reflected in considerable variation in clinical practice. There are significant differences between dose requirements during elective and intrapartum caesarean section. Standard recommended doses are higher than required, with the potential for acute cardiovascular adverse effects. We recommend a small initial bolus dose of oxytocin, followed by a titrated infusion. The recommended doses of oxytocin may have to be increased in women with risk factors for uterine atony. Carbetocin at equipotent doses to oxytocin has similar actions, while avoiding the requirement for a continuous infusion after the initial dose and reducing the need for additional uterotonics. As with oxytocin, carbetocin dose requirements are higher for intrapartum caesarean sections. A second-line agent should be considered early if oxytocin/carbetocin fails to produce good uterine tone. Women with cardiac disease may be very sensitive to the adverse effects of oxytocin and other uterotonics, and their management needs to be individualised., (© 2019 Association of Anaesthetists.)

Purpose: The optimal epidural mixtures and settings for programmed intermittent epidural bolus (PIEB) labour analgesia have yet to be determined. A previous study by our group demonstrated that 10 mL boluses of bupivacaine 0.0625% with fentanyl 2 µg·mL -1 administered every 40 min provided effective analgesia during the first stage of labour for 90% of women, without breakthrough pain. We wanted to determine the effective PIEB time interval of 5 mL boluses of bupivacaine 0.125% with fentanyl 2 µg·mL -1 under the same study circumstances, aiming at a future comparative study., Methods: This double-blind dose-finding study used the biased coin up-and-down sequential allocation method to determine the effective PIEB interval 90% (EI90) needed to provide effective analgesia without breakthrough pain during the first stage of labour. We used fixed 5 mL boluses of bupivacaine 0.125% with fentanyl 2 µg.mL -1 and studied time intervals of 60, 50, 40, and 30 min. The first patient was assigned an interval of 60 min and the remaining intervals were assigned as per the biased coin up-and-down method., Results: The estimated EI90 was 36.5 min (95% confidence interval [CI], 34.0 to 39.0) by the truncated Dixon and Mood method and 34.2 min (95% CI, 30.8 to 41.5) by the isotonic regression method. We found that 20/40 women had an upper sensory block to ice above T6, 34/40 women had no motor block, and no woman required treatment for hypotension., Conclusion: The EI90 between 5 mL boluses of bupivacaine 0.125% with fentanyl 2 µg·mL -1 during the first stage of labour is approximately 35 min., Trial Registration: www.clinicaltrials.gov (NCT #02758405); registered 2 May, 2016.

Background: Placenta accreta spectrum (PAS) disorders are a potentially life-threatening complication of pregnancy that demand coordinated interdisciplinary care to achieve safer outcomes. The rising incidence of this disease is due to a growing number of uterine surgical procedures, including the rising incidence of pregnancy following Caesarean section., Objective: To provide current evidence-based guidelines on the optimal methods used to effectively screen, diagnose, and manage PAS disorders., Methods: Members of the guideline committee were selected on the basis of their ongoing expertise in managing this condition across Canada and by practice setting. The committee reviewed all available evidence in the English medical literature, including published guidelines, and evaluated diagnostic tests, surgical procedures, and clinical outcomes., Evidence: Published literature, including clinical practice guidelines, was retrieved through searches of Medline and The Cochrane Library to March 2018 using appropriate controlled vocabulary and key words. Results were restricted to systematic reviews, randomized controlled trials, and observational studies written in English. Searches were updated on a regular basis and incorporated in the guideline to July 2018., Values: The quality of evidence in this document was graded using the criteria described in the Report of the Canadian Task Force on Preventive Health Care., Results: This document reviews the evidence regarding the available diagnostic and surgical techniques used for optimal management of women with suspected PAS disorders, including anaesthesia and practical considerations for interdisciplinary care., Benefits, Harms, and Costs: Implementation of the guideline recommendations will improve awareness of this disease and increase the proportion of affected women receiving interdisciplinary care in regional centres., Conclusions: Interdisciplinary team-based care providing accurate diagnostic services, coordinated planning, and safer surgery deliver effective care with improved clinical outcomes in comparison with alternative management., Summary Statements: RECOMMENDATIONS., (Copyright © 2019 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.)

Background: Prolonged continuous oxytocin administration during labor may induce oxytocin receptor desensitization, which attenuates the response of the myometrium to further oxytocin, increasing the risk of postpartum hemorrhage. The literature comparing pulsatile (intermittent) versus continuous oxytocin administration for induction and augmentation of labor is inconsistent with regard to maternal outcomes. We aimed to determine the effect of intermittent versus continuous oxytocin preexposure on myometrial responsiveness to subsequent oxytocin. We hypothesized that intermittent oxytocin pretreatment would result in superior subsequent oxytocin-induced contractility than continuous oxytocin pretreatment., Methods: This in vitro study was undertaken using myometrium obtained from women undergoing elective cesarean deliveries. Each myometrial strip was mounted in an individual organ bath with physiological salt solution under homeostatic conditions and allocated to one of 3 groups: (1) control (no pretreatment); (2) continuous (pretreatment with oxytocin 10(-5) M for 2 hours); or (3) intermittent (pretreatment with alternating oxytocin 10 M and physiological salt solution every 15 minutes, for 2 hours). After pretreatment, dose-response testing to oxytocin 10(-5) to 10(-5) M was performed and contractile parameters were measured. The primary outcome was motility index (MI, amplitude × frequency) of contractions., Results: Eighteen women were recruited, and 86 successful experiments were performed (control n = 29, continuous n = 28, intermittent n = 29). The means (standard errors) of MI (√g·contractions/10 min) in the control, continuous, and intermittent groups were 2.34 (0.09), 1.78 (0.09), and 2.13 (0.11), respectively. The MI was significantly reduced in the continuous group when compared to the control (estimated difference [95% confidence interval {CI}], -0.56 [-0.81 to -0.31]; P < .01) and intermittent group (estimated difference [95% CI], -0.35 [-0.62 to -0.08]; P = .01). There was no significant difference in MI between the intermittent and control group (estimated difference [95% CI], -0.21 [-0.51 to 0.09]; P = .17)., Conclusions: Human myometrium remains more responsive to subsequent oxytocin after intermittent compared to continuous exposure to oxytocin, most likely due to reduction in oxytocin receptor desensitization, or facilitation of receptor resensitization in the intermittent group. Hence, intermittent oxytocin administration during labor warrants further investigation as a technique to preserve uterine oxytocin responsiveness.