Papers by Brendan Carvalho
BJA Education, 2020
Describe the risk factors associated with the failure of converting epidural analgesia for labour... more Describe the risk factors associated with the failure of converting epidural analgesia for labour to anaesthesia for Caesarean section. Discuss the merits and limitations of the methods used to confirm the correct location of the epidural catheter and the techniques used to evaluate the adequacy of neuraxial blockade. Debate the advantages and disadvantages of the different drugs used in the epidural top-up solution. Explain the implications of the options for management after a failed epidural top-up.
Research Square (Research Square), Feb 23, 2023
Introduction: Strategies to achieve e ciency in non-operating room locations have been described,... more Introduction: Strategies to achieve e ciency in non-operating room locations have been described, but emergencies and competing priorities in a birth unit can make setting optimal sta ng and operation benchmarks challenging. This study used Queuing Theory Analysis (QTA) to identify optimal birth center operating room (OR) and sta ng resources using real-world data. Methods: Data from a Level 4 Maternity Center (9,626 births/year, cesarean delivery (CD) rate 32%) were abstracted for all labor and delivery operating room activity from July 2019-June 2020. QTA has two variables: Mean Arrival Rate, λ and Mean Service Rate µ. QTA formulas computed probabilities: P 0 = 1-(λ/ µ) and P n = P 0 (λ/µ) n where n = number of patients. P 0…n is the probability there are zero patients in the queue at a given time. Multiphase multichannel analysis was used to gain insights on optimal staff and space utilization assuming a priori safety parameters (i.e., 30 min decision to incision in unscheduled CD; ≤5 min for emergent CD; no greater than 8 hours for nil per os time). To achieve these safety targets, a < 0.5% probability that a patient would need to wait was assumed. Results: There were 4,017 total activities in the operating room and 3,092 CD in the study period. Arrival rate λ was 0.45 (patients per hour) at peak hours 07:00-19:00 while λ was 0.34 over all 24 hours. The service rate per OR team (µ) was 0.87 (patients per hour) regardless of peak or overall hours. The number of server teams (s) dedicated to OR activity was varied between two and ve. Over 24 hours, the probability of no patients in the system was P 0 = 0.61, while the probability of 1 patient in the system was P 1 = 0.23, and the probability of 2 or more patients in the system was P ≥ 2 = 0.05
The Journal of Maternal-Fetal & Neonatal Medicine
Anesthesia & Analgesia
The prevalence of pregnant people with opioid use disorder (OUD), including those receiving medic... more The prevalence of pregnant people with opioid use disorder (OUD), including those receiving medications for opioid use disorder (MOUD), is increasing. Challenges associated with pain management in people with OUD include tolerance, opioid-induced hyperalgesia, and risk for return to use. Yet, there are few evidence-based recommendations for pain management in the setting of pregnancy and the postpartum period, and many peripartum pain management studies exclude people with OUD. This scoping review summarized the available literature on peridelivery pain management in people with OUD, methodologies used, and identified specific areas of knowledge gaps. PubMed and Embase were comprehensively searched for publications in all languages on peripartum pain management among people with OUD, both treated with MOUD and untreated. Potential articles were screened by title, abstract, and full text. Data abstracted were descriptively analyzed to map available evidence and identify areas of limi...
Anaesthesia Critical Care & Pain Medicine
Cureus
Objective: Racial and ethnic disparities in peripartum blood loss and postpartum hemorrhage (PPH)... more Objective: Racial and ethnic disparities in peripartum blood loss and postpartum hemorrhage (PPH) have not been adequately evaluated. We sought to compare postpartum blood loss and PPH in African American and Hispanic parturients compared to other groups. Methods: This was a secondary analysis of an observational study at a tertiary academic center of a historical (August 2016 to January 2017) and interventional (August 2017 to January 2018) cohort of 7618 deliveries. Visual estimation of blood loss (EBL) was used in the historical group and quantitative blood loss (QBL) was implemented in the intervention group. Our primary endpoint was median blood loss in African Americans versus other racial groups between cohorts. Results: A total of 7618 deliveries were evaluated; 755 (9.9%) were identified as African American with 1035 (13.6%) identifying as Hispanic. Blood loss was similar in racial groups using EBL (p=0.131), but not QBL that was 430 (227-771) in African Americans and 348 (200-612) in non-African Americans (p<0.001). PPH was greater among African Americans in both groups (10.3% vs. 6.9% in EBL cohort, p=0.023, and 16.9% vs. 11.6% in QBL cohort, p<0.001). Conclusion: Racial and ethnic differences in peripartum blood loss were more apparent with QBL than EBL. It is unknown if these differences are caused by provider cognitive bias, socioeconomic differences, language barriers and/or other factors.
Anesthesia & Analgesia
BACKGROUND: To predict opioid consumption and pain intensity after the index cesarean delivery, w... more BACKGROUND: To predict opioid consumption and pain intensity after the index cesarean delivery, we tested a hypothesis that opioid consumption after the previous cesarean delivery of the same patient can predict the opioid consumption after the index cesarean delivery. We further tested a secondary hypothesis that the pain scores after the previous cesarean delivery can predict the pain scores after the index cesarean delivery. METHODS: This is a retrospective cohort study of 470 women who underwent both previous and index cesarean deliveries at a single institution from January 2011 to June 2019. To predict the opioid consumption (primary outcome) and average pain scores (on 11-point numeric rating scale) after their index cesarean delivery, we used a linear regression model incorporating only the opioid consumption and average pain scores after the previous cesarean delivery, respectively (unadjusted models). Demographic and obstetric variables were then added as predictors (adjus...
Journal of Clinical Anesthesia
Anaesthesia, 2021
We thank Drs Carvalho and Sultan for their editorial [1] accompanying the article by Chapron et a... more We thank Drs Carvalho and Sultan for their editorial [1] accompanying the article by Chapron et al. [2] on retaining bupivacaine as the most frequently utilised intrathecal local anaesthetic for caesarean section. When discussing specific side effects of prilocaine, induction of methaemoglobinaemia by its major metabolite o-toluidine is consistently cited as the most important cause of drug intolerance. However, it should been understood that otoluidine is a genotoxic compound giving rise to DNA adducts in the human urinary bladder [3]. In 2010, otoluidine was classified as a human carcinogen by the International Agency of Research on Cancer [4], mainly based on human bladder cancer data after occupational exposure. After a single dose of 100 mg prilocaine in head and neck surgery patients, haemoglobin adducts of otoluidine, as a surrogate marker of its metabolic activation, are of the same order of magnitude as the adduct levels in workers with a high incidence of bladder cancer employed at a chemical plant in Niagara Falls, New York State [5]. This has been confirmed recently by Guntz et al. [6] following intrathecal administration of hyperbaric prilocaine in patients for lower limb surgery. As a threshold of effect cannot normally be determined for carcinogenic substances (i.e. there is no concentration at which the substance is entirely safe), the goal is to avoid exposure whenever possible. Therefore, prilocaine should not be used as a local anaesthetic if alternative local anaesthetics with improved clinical safety profiles are available. E.Weber E. Richter Ludwig-Maximilians-University, Munich, Germany Email: [email protected]
A&A Practice, 2021
Pregnant patients with high-risk conditions including abnormal placentation or severe cardiovascu... more Pregnant patients with high-risk conditions including abnormal placentation or severe cardiovascular disease may require large-bore central venous access at the time of delivery. Central lines are generally inserted while obstetric patients are awake, either because neuraxial anesthesia is planned or to minimize fetal exposure to anesthetic medications. Despite local infiltration, the procedure can cause significant patient discomfort. This case series describes use of a superficial cervical plexus block (SCPB) to facilitate line placement in 4 pregnant women with high-risk conditions. SCPB is technically straightforward with low reported complication rates and should be considered for pregnant patients requiring large-bore central lines.
International Journal of Obstetric Anesthesia, 2021
BACKGROUND Ultrasound may be useful to identify the spinal anesthesia insertion point, particular... more BACKGROUND Ultrasound may be useful to identify the spinal anesthesia insertion point, particularly when landmarks are not palpable. We tested the hypothesis that the number of needle redirections/re-insertions is lower when using a handheld ultrasound device compared with palpation in obese women undergoing spinal anesthesia for cesarean delivery. METHODS Study recruits were obese (body mass index (BMI) >30 kg/m2) women with impalpable bony landmarks who were undergoing spinal anesthesia for elective cesarean delivery. Women were randomized to ultrasound or palpation. The primary study outcome was a composite between-group comparison of total number of needle redirections (any withdrawal and re-advancement of the needle and/or introducer within the intervertebral space) or re-insertions (any new skin puncture in the same or different intervertebral space) per patient. Secondary outcomes included insertion site identification time and patient verbal numerical pain score (0-10) for comfort during surgical skin incision. RESULTS Forty women completed the study. The mean BMI (standard deviation) for the ultrasound group was 39.8 (5.5) kg/m2 and for the palpation group 37.3 (5.2) kg/m2. There was no difference in the composite primary outcome (median (interquartile range) [range]) between the ultrasound group (4 (2-13) [2-22]) and the (6 (4-10) [1-17]) palpation group (P=0.22), with the 95% confidence interval of the difference 2 (-1.7 to 5.7). There were no differences in the secondary outcomes. CONCLUSIONS Handheld ultrasound did not demonstrate any advantages over traditional palpation techniques for spinal anesthesia in an obese population undergoing cesarean delivery, although the study was underpowered to show a difference.
Anesthesia & Analgesia, 2021
BACKGROUND: Pregnancy-related cardiovascular physiologic changes increase the likelihood of pulmo... more BACKGROUND: Pregnancy-related cardiovascular physiologic changes increase the likelihood of pulmonary edema, with the risk of fluid extravasating into the pulmonary interstitium being potentially at a maximum during the early postpartum period. Data on the impact of labor and peripartum hemodynamic strain on lung ultrasound (LUS) are limited, and the prevalence of subclinical pulmonary interstitial syndrome in peripartum women is poorly described. The primary aim of this exploratory study was to estimate the prevalence of pulmonary interstitial syndrome in healthy term parturients undergoing vaginal (VD), elective (eCD), and unplanned intrapartum cesarean deliveries (uCD). Secondary aims were to estimate the prevalence of positive lung regions (≥3 B-lines on LUS per region) and to assess the associations between positive lung regions and possible contributing factors. METHODS: In this prospective observational cohort study, healthy women at term undergoing VD, eCD, or uCD were enrol...
American Journal of Obstetrics & Gynecology MFM, 2020
BACKGROUND: Few adequately validated patient-reported outcome measures are available, which can a... more BACKGROUND: Few adequately validated patient-reported outcome measures are available, which can assess recovery profiles following childbirth. OBJECTIVE: We aimed to determine whether quantitative recovery (using the Obstetric Quality of Recovery-10 patient-reported outcome measure) was superior following vaginal delivery compared with cesarean delivery and evaluate validity, reliability, and responsiveness of this patientreported outcome measure in the obstetrical setting in the United States. STUDY DESIGN: Women recruited into this single-center observational cohort study completed the Obstetric Quality of Recovery-10 and EuroQol 5-dimension 3L patient-reported outcome measures within 72 hours of childbirth. We assessed the validity with hypothesis testing and structural validity. In hypothesis testing, the primary outcome was Obstetric Quality of Recovery-10 scores after vaginal vs cesarean delivery. Secondary outcomes were differences in Obstetric Quality of Recovery-10 scores for vaginal delivery following induction of labor vs spontaneous labor and scheduled vs unplanned cesarean delivery, correlation with clinical parameters (American Society of Anesthesiologists classification grade, body mass index, length of hospital stay, estimated blood loss, transfusion requirement, antiemetic use, and neonatal intensive care unit admission), and qualitative ranking of Obstetric Quality of Recovery-10 items for each delivery mode. Structural validity was assessed by determining the correlation of the Obstetric Quality of Recovery-10 scores with the EuroQol 5-dimension 3L and global health visual analog scale scores. Reliability was assessed using Cronbach alpha and inter-item correlation of Obstetric Quality of Recovery-10 items. Responsiveness was assessed by evaluating the change in Obstetric Quality of Recovery-10 scores over the 72-hour postpartum period. RESULTS: Data from 215 women were analyzed. In hypothesis testing, the median (interquartile range) Obstetric Quality of Recovery-10 scores were higher following vaginal delivery than cesarean delivery (86 [77e94] vs 77 [64e86], respectively; P<.001). Multivariate model demonstrated that Obstetric Quality of Recovery-10 scores were significantly lower after cesarean delivery when adjusting for American Society of Anesthesiologists classification grade, age, body mass index, and ethnicity (R¼À8.97; P<.001). Obstetric Quality of Recovery-10 scores were similar between induction of labor and spontaneous labor, and scheduled cesarean delivery and unplanned cesarean delivery. Obstetric Quality of Recovery-10 was correlated with length of hospital stay (R¼À0.248; P<.001), estimated blood loss (R¼À0.3429; P<.001), transfusion requirement (R¼À0.140; P¼.041), and antiemetic use (R¼À0.280; P<.001). The highest ranked Obstetric Quality of Recovery-10 items were ability to hold baby, feeling in control, and ability to look after personal hygiene. The lowest ranked items were pain and shivering. In structural validity, correlation of Obstetric Quality of Recovery-10 score was moderate with the global health visual analog scale (r¼0.511) and EuroQol 5-dimension 3L scores (r¼À0.509). In reliability, Cronbach alpha was 0.72 and more than 80% of individual items correlated. In responsiveness, Obstetric Quality of Recovery-10 scores did not change significantly over the study period. CONCLUSION: Quantitative inpatient recovery following vaginal delivery is superior to cesarean delivery. The Obstetric Quality of Recovery-10 appears to be a valid and reliable patient-reported outcome measure following these delivery modes. Further studies are needed to determine how to improve recovery domains identified in this study, to evaluate Obstetric Quality of Recovery-10 in different languages and determine whether these domains impact outcomes beyond hospitalization.
Journal of Clinical Anesthesia, 2019
Virtual reality successfully provides anxiolysis to laboring women undergoing epidural placement ... more Virtual reality successfully provides anxiolysis to laboring women undergoing epidural placement Fig. 1. VR usage post-epidural placement. The patient continued to wear the VR headset after receiving epidural anesthesia as a form of relaxation.
International Journal of Obstetric Anesthesia, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
American Journal of Obstetrics and Gynecology, 2019
OBJECTIVE: To compare post-operative outcomes of skin closure with staples vs antibacterial knotl... more OBJECTIVE: To compare post-operative outcomes of skin closure with staples vs antibacterial knotless suture (AKS) during elective cesarean delivery. STUDY DESIGN: we conducted a retrospective cohort study of all women who had an elective cesarean delivery (ECD) in a single, university-affiliated medical center between January 2014 and December 2017. During this time, we have gradually changed our technique for skin closure at all cesarean deliveries from staples to AKS. The primary outcome was post-operative infection rate (defined as post-operative white blood count (WBC)
A&A Practice, 2019
We describe the management of a pregnant patient with osteogenesis imperfecta with a history of n... more We describe the management of a pregnant patient with osteogenesis imperfecta with a history of numerous fractures, severe scoliosis, and anticipated difficult airway. Her pregnancy was complicated by progressive shortness of breath and a fetal diagnosis of osteogenesis imperfecta. Spine anatomy precluded neuraxial anesthesia. Cesarean delivery was performed under general anesthesia at 34 weeks. Immediately after awake fiberoptic intubation and induction of general anesthesia, capnography waveform was lost with rapid profound oxygen desaturation. A supraglottic airway device was placed, oxygenation maintained with supraglottic airway and positive pressure ventilation throughout case, and the baby was delivered with Apgars of 8 and 9.
Journal of patient safety, Jan 26, 2018
The impact of the electronic medical record (EMR) on nursing workload is not well understood. The... more The impact of the electronic medical record (EMR) on nursing workload is not well understood. The objective of this descriptive study was to measure the actual and perceived time that nurses spend on the EMR in the operating room during cesarean births. Twenty scheduled cesarean births were observed. An observer timed the circulating nurse's EMR use during each case. Immediately after each case, the nurse completed a questionnaire to estimate EMR time allocation during the case and their desired time allocation for a typical case. They were also asked about time allotted to various activities preoperatively, intraoperatively, and postoperatively for a typical cesarean birth. Mean observed nurse EMR time was 36 ± 12 minutes per case, 40% ± 10% of the duration of the cesarean delivery. Nurses tended to estimate greater time spent on the EMR; the perceived mean proportion of time spent on the EMR (55%) was greater than the actual timed value of 40% (P = 0.020). Nurse's desired ...
Anesthesia and analgesia, Jan 30, 2017
This study investigated the accuracy of a wireless handheld ultrasound with pattern recognition s... more This study investigated the accuracy of a wireless handheld ultrasound with pattern recognition software that recognizes lumbar spine bony landmarks and measures depth to epidural space (Accuro, Rivanna Medical, Charlottesville, VA) (AU). AU measurements to epidural space were compared to Tuohy needle depth to epidural space (depth to loss of resistance at epidural placement). Data from 47 women requesting labor epidural analgesia were analyzed. The mean difference between depth to epidural space measured by AU versus needle depth was -0.61 cm (95% confidence interval, -0.79 to -0.44), with a standard deviation of 0.58 (95% confidence interval, 0.48-0.73). Using the AU-identified insertion point resulted in successful epidural placement at first attempt in 87% of patients, 78% without redirects.
Anesthesia & Analgesia, 2017
BACKGROUND: Remifentanil may be used by laboring women for analgesia, despite controversy because... more BACKGROUND: Remifentanil may be used by laboring women for analgesia, despite controversy because of potential apneas. We evaluated candidate variables as early warning alerts for apnea, based on prevalence, positive predictive rate, sensitivity for apnea event detection, and early warning alert time intervals (lead time) for apnea. METHODS: We performed a secondary analysis of respiratory physiological data that had been collected during a prospective IRB-approved study of laboring women receiving IV patient-controlled boluses of remifentanil 20 to 60 μg every 1 to 2 minutes. Analyzed data included the respiratory rate (RR), end-tidal CO2 (Etco 2), pulse oximetry (Spo 2), heart rate (HR), and the Integrated Pulmonary Index (IPI; Capnostream 20; Medtronic, Boulder, CO) that had been recorded continuously throughout labor. We defined immediate early warning alerts as any drop in a variable value below a prespecified threshold for 15 seconds: RR < 8 breaths per minute (bpm), Etco 2...
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Papers by Brendan Carvalho