Maternal Fever Associated With Continuous Spinal Versus Epidural Labor Analgesia: A Single-Center Retrospective Study.

BACKGROUND: Neuraxial labor analgesia is associated with elevations in maternal temperature; the mechanism responsible is unknown. Proposed mechanisms have included infection, altered thermoregulation, and inflammation, potentially triggered by local anesthetics. Studies of the association between neuraxial labor analgesia and maternal fever have focused on epidural analgesia, and there have been no comparisons of the rate of maternal fever between continuous spinal and epidural labor analgesia. METHODS: We performed a retrospective study to compare the rate of maternal fever between patients who received continuous spinal versus epidural labor analgesia between June 2012 and March 2020. Each patient who received continuous spinal analgesia was matched to 2 patients who received epidural analgesia and had the same nulliparous status. The primary outcome of our study was the incidence of intrapartum maternal fever, which we defined as any temperature ≥38 °C before delivery and compared between the continuous spinal and epidural groups using Fisher exact test. RESULTS: We identified 81 patients who received continuous spinal analgesia and 162 matched controls who received epidural analgesia. Demographic and obstetric characteristics of the patients were similar between groups. While the duration of analgesia did not significantly differ, there was markedly increased bupivacaine consumption in women with epidural analgesia. Eight of 81 (9.9%; 95% confidence interval [CI], 5.1-18.3) women with continuous spinal analgesia developed an intrapartum fever compared to 18 of 162 (11.1%; 95% CI, 7.1-16.9) of women with epidural analgesia ( P = .83; Fisher exact test). CONCLUSIONS: There was no significant difference in the rate of maternal fever between women with continuous spinal compared to epidural labor analgesia. While the route of administration and dose of bupivacaine differs between epidural and spinal labor analgesia, they are titrated to produce similar levels of neuraxial blockade. Our results are consistent with a model in which epidural related maternal fever is due to altered thermoregulation from a central neuraxial block and argue against a direct effect of bupivacaine or fentanyl, although we cannot rule out a concentration-independent effect of bupivacaine or fentanyl or an inflammatory effect of the catheter itself. These retrospective results highlight the importance of prospective and mechanistic study of neuraxial analgesia-related maternal fever.

Comparison of early warning scores for predicting clinical deterioration and infection in obstetric patients.

BACKGROUND: Early warning scores are designed to identify hospitalized patients who are at high risk of clinical deterioration. Although many general scores have been developed for the medical-surgical wards, specific scores have also been developed for obstetric patients due to differences in normal vital sign ranges and potential complications in this unique population. The comparative performance of general and obstetric early warning scores for predicting deterioration and infection on the maternal wards is not known. METHODS: This was an observational cohort study at the University of Chicago that included patients hospitalized on obstetric wards from November 2008 to December 2018. Obstetric scores (modified early obstetric warning system (MEOWS), maternal early warning criteria (MEWC), and maternal early warning trigger (MEWT)), paper-based general scores (Modified Early Warning Score (MEWS) and National Early Warning Score (NEWS), and a general score developed using machine learning (electronic Cardiac Arrest Risk Triage (eCART) score) were compared using the area under the receiver operating characteristic score (AUC) for predicting ward to intensive care unit (ICU) transfer and/or death and new infection. RESULTS: A total of 19,611 patients were included, with 43 (0.2%) experiencing deterioration (ICU transfer and/or death) and 88 (0.4%) experiencing an infection. eCART had the highest discrimination for deterioration (p < 0.05 for all comparisons), with an AUC of 0.86, followed by MEOWS (0.74), NEWS (0.72), MEWC (0.71), MEWS (0.70), and MEWT (0.65). MEWC, MEWT, and MEOWS had higher accuracy than MEWS and NEWS but lower accuracy than eCART at specific cut-off thresholds. For predicting infection, eCART (AUC 0.77) had the highest discrimination. CONCLUSIONS: Within the limitations of our retrospective study, eCART had the highest accuracy for predicting deterioration and infection in our ante- and postpartum patient population. Maternal early warning scores were more accurate than MEWS and NEWS. While institutional choice of an early warning system is complex, our results have important implications for the risk stratification of maternal ward patients, especially since the low prevalence of events means that small improvements in accuracy can lead to large decreases in false alarms.

Thromboelastographic Assessment of Fibrinolytic Activity in Postpartum Hemorrhage: A Retrospective Single-Center Observational Study.

BACKGROUND: Postpartum hemorrhage is a leading cause of maternal mortality. Antifibrinolytic therapy has the potential to influence outcomes in postpartum hemorrhage, but the incidence of elevated fibrinolytic activity in postpartum hemorrhage is unknown. METHODS: We retrospectively reviewed thromboelastography (TEG) results obtained for postpartum hemorrhage from 118 deliveries at The University of Chicago. TEG results were obtained as part of our postpartum hemorrhage protocol when blood loss exceeded 500 mL after vaginal delivery or 1000 mL after cesarean delivery. Our primary outcome was the incidence of elevated fibrinolytic activity, which we predefined as clot lysis ≥3% at 30 minutes (Ly30) on kaolin TEG. Platelet-mediated clot retraction can also lead to an elevated Ly30 on kaolin TEG. Therefore, to distinguish between fibrinolysis and clot retraction, we evaluated clot lysis using functional fibrinogen TEG, which contains a platelet inhibitor. We considered a kaolin TEG Ly30 ≥3% in conjunction with a nonzero functional fibrinogen TEG Ly30 suggestive of elevated fibrinolytic activity. We also recorded quantitative blood loss, primary etiology of hemorrhage, standard laboratory measurements of coagulation, and demographic and obstetric characteristics of the study population. RESULTS: The median kaolin TEG Ly30 was 0.2% (interquartile range: 0%-0.8%). Fifteen of 118 women (12.7%; 95% confidence interval, 7.9%-19.9%) had kaolin TEG Ly30 values ≥3%. Of 15 patients with elevated Ly30 values, functional fibrinogen TEG Ly30 was available for 13, of which none demonstrated detectable clot lysis. CONCLUSIONS: Our observation that none of the patients in our sample with kaolin TEG Ly30 values ≥3% had a nonzero functional fibrinogen TEG Ly30 value suggests that the observed elevations in kaolin TEG Ly30 may have been secondary to platelet-mediated clot retraction as opposed to fibrinolysis. Platelet-mediated clot retraction should be distinguished from fibrinolysis when assayed using viscoelastic techniques in postpartum hemorrhage. Further research is necessary to determine the optimal methods to assess fibrinolytic activity in postpartum hemorrhage.

National Partnership for Maternal Safety Recommended Maternal Early Warning Criteria Are Associated With Maternal Morbidity.

BACKGROUND: Many cases of maternal mortality and morbidity are preventable. A delayed response to clinical warning signs contributes to preventability. Therefore, the National Partnership for Maternal Safety devised maternal early warning criteria (MEWC), composed of abnormal vital signs that trigger bedside evaluation by a provider with the capacity to escalate care. The relationship of the MEWC to maternal morbidity has not been studied. We evaluated the correlation between the MEWC and maternal morbidity. METHODS: We retrospectively reviewed the first 400 deliveries at the University of Chicago in 2016. We analyzed the electronic medical record to determine whether vital signs triggered the MEWC during the admission to labor and delivery and whether patients experienced morbidity during their delivery hospitalization. The association between MEWC and morbidity was tested using χ analysis. We calculated the sensitivity, specificity, and positive and negative predictive values of the MEWC. RESULTS: Two hundred eighty-one (70%) of 400 patients triggered the MEWC at least once, and 198 (50%) of 400 patients had multiple or recurrent triggers. Ninety-nine (25%) of 400 patients experienced morbidity. The most common causes of morbidity were hemorrhage, suspected infection, and preeclampsia with severe features. The relative risk of maternal morbidity with at least a single trigger was 13.55 (95% confidence interval [CI], 4.38-41.91) and with recurrent or multiple triggers was 5.29 (95% CI, 3.22-8.71). The sensitivity of the MEWC in predicting morbidity was 0.97 (95% CI, 0.92-0.99) and the specificity was 0.39 (95% CI, 0.33-0.44) when patients with at least a single trigger were included. When including only patients with multiple or recurrent triggers, the sensitivity was 0.84 (95% CI, 0.75-0.90) and the specificity was 0.62 (95% CI, 0.56-0.67). The positive predictive value of the MEWC in our population was 0.34 (95% CI, 0.29-0.40), and the negative predictive value was 0.97 (95% CI, 0.93-0.99). When considering only patients with multiple or recurrent triggers, the positive predictive value was 0.42 (95% CI, 0.38-0.46) and the negative predictive value was 0.92 (95% CI, 0.88-0.95). CONCLUSIONS: The MEWC are associated with maternal morbidity. As a screening tool, they appropriately prioritize sensitivity and have an excellent negative predictive value. The criteria demonstrate low specificity, which is slightly improved by considering only patients with recurrent or multiple triggers. Additional efforts to improve the specificity of MEWC, with a focus on identifying sustained or recurrent patterns of abnormal vital signs, may be necessary before their widespread implementation.

Microparticle Release During Normal Cesarean Delivery.

Coagulation increases during pregnancy and peaks during parturition. We hypothesized that an increase in microparticle (MP) levels in plasma occurs around the time of placental separation and subsides over several hours. We performed a prospective observational pilot study to investigate plasma MP levels in healthy parturients immediately before and after cesarean delivery. The primary outcome was MP levels at postdelivery time points compared to baseline levels. Samples underwent flow cytometry and staining to determine MP levels. Placental-derived MPs were further characterized for the presence of procoagulant proteins. Placental-derived MPs increased immediately after delivery before returning to baseline in healthy parturients.

Patients Undergoing Cesarean Delivery After Exposure to Oxytocin During Labor Require Higher Postpartum Oxytocin Doses.

BACKGROUND: Experts recommend postpartum oxytocin to prevent uterine atony and hemorrhage, but oxytocin may be associated with dose-dependent adverse effects, and the correct dose of postpartum oxytocin has yet to be determined. The effective dose in 90% of patients (ED90) of oxytocin after cesarean delivery may be higher in patients exposed to oxytocin during labor compared to patients unexposed. We therefore undertook this study to compare postpartum oxytocin requirements in patients exposed to oxytocin prior to cesarean delivery versus those not exposed, when all were treated according to a specific institutional protocol. METHODS: In this retrospective chart review, we reviewed medical records of patients who underwent cesarean delivery under neuraxial anesthesia and noted demographic data, relevant comorbidities, and oxytocin exposure, infusion rate, and duration prior to delivery. Patients exposed to oxytocin before cesarean (OXY+ group) were compared to those not exposed (OXY- group). The primary outcome variable was highest infusion rate of postpartum oxytocin required per institutional protocol. Secondary outcomes included estimated blood loss, proportion of patients with postpartum hemorrhage, and proportions who received other uterotonic medications or red blood cell transfusion. RESULTS: OXY+ patients were more likely to be nulliparous and had higher estimated gestational age and neonatal weight than OXY- patients. They also had higher incidence of chorioamnionitis and lower incidence of multiple gestation. OXY+ patients required a high postpartum oxytocin infusion rate more often than OXY- patients (adjusted odds ratio 1.94 [95% confidence interval, 1.19-3.15; P = .008]). They also received other uterotonic agents more commonly. Estimated blood loss, hemorrhage rates, and transfusion rates did not differ between groups. CONCLUSIONS: Reported increases in the ED90 of postpartum oxytocin after oxytocin exposure during labor appear to be clinically significant. We have therefore altered our institutional protocol so that women preexposed to oxytocin routinely receive higher initial postpartum oxytocin infusion rates.

Massive Transfusion Protocols: A Survey of Academic Medical Centers in the United States.

BACKGROUND: Massive transfusion protocols (MTPs) have been adopted in many hospitals, and they may improve outcomes, as well as decrease the number of blood products transfused. However, there are no specific guidelines regarding the number and types of products that should be included in these protocols. MTPs may vary from hospital to hospital. METHODS: A short, web-based survey was sent to blood bank medical directors at academic institutions to learn details about MTPs. RESULTS: A total of 107 survey requests were sent, and 56 were completed (52% response rate). All who responded had an MTP in place. Nearly all (n = 55, 98.2% [95% CI, 90.6%-99.7%]) base their protocol on delivery of fixed amounts and ratios of blood products, with only a minority incorporating any elements of laboratory-directed therapy. The most common target, red blood cell (RBC):plasma ratio, is 1:1 (n = 39, 69.9% [95% CI, 56.7%-80.1%] of respondents). The majority (n = 36, 64.3% [95% CI, 51.2%-75.6%]) provide 6 or more units of red blood cells in the first MTP packet. CONCLUSIONS: One-hundred percent of survey respondents had an MTP in place. Despite a lack of published guidelines regarding MTPs, the survey results demonstrated substantial uniformity in numbers of products and target transfusion ratios.

National Partnership for Maternal Safety: Consensus Bundle on Severe Hypertension During Pregnancy and the Postpartum Period.

Complications arising from hypertensive disorders of pregnancy are among the leading causes of preventable severe maternal morbidity and mortality. Timely and appropriate treatment has the potential to significantly reduce hypertension-related complications. To assist health care providers in achieving this goal, this patient safety bundle provides guidance to coordinate and standardize the care provided to women with severe hypertension during pregnancy and the postpartum period. This is one of several patient safety bundles developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. These safety bundles outline critical clinical practices that should be implemented in every maternity care setting. Similar to other bundles that have been developed and promoted by the Partnership, the hypertension safety bundle is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and Systems Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. This commentary provides information to assist with bundle implementation.

Cranial nerve VI palsy after dural-arachnoid puncture.

In this article, we provide a literature review of cranial nerve (CN) VI injury after dural-arachnoid puncture. CN VI injury is rare and ranges in severity from diplopia to complete lateral rectus palsy with deviated gaze. The proposed mechanism of injury is cerebrospinal fluid leakage causing intracranial hypotension and downward displacement of the brainstem. This results in traction on CN VI leading to stretch and neural demyelination. Symptoms may present 1 day to 3 weeks after dural-arachnoid puncture and typically are associated with a postdural puncture (spinal) headache. Resolution of symptoms may take weeks to months. Use of small-gauge, noncutting spinal needles may decrease the risk of intracranial hypotension and subsequent CN VI injury. When ocular symptoms are present, early administration of an epidural blood patch may decrease morbidity or prevent progression of ocular symptoms.

National Partnership for Maternal Safety: consensus bundle on obstetric hemorrhage.

Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and System Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation.

The use of postpartum hemorrhage protocols in United States academic obstetric anesthesia units.

BACKGROUND: Postpartum hemorrhage (PPH) is the leading cause of severe maternal morbidity, cardiac arrest, and death during the hospitalization for childbirth. Protocol-driven care has been associated with improved outcomes in many settings; the National Partnership for Maternal Safety now recommends that PPH protocols be implemented in every labor and delivery unit in the United States. In this study, we sought to identify the level of PPH protocol availability in academic United States obstetric units. We hypothesized that the majority (>80%) of academic obstetric anesthesia units would have a PPH protocol in place. METHODS: A survey was developed by an expert panel. Domains included hospital characteristics, availability of PPH protocol or plans to develop such a protocol, and protocol components included in the upcoming National Partnership for Maternal Safety obstetric hemorrhage safety bundle initiative. The electronic survey was emailed to the 104 directors of United States academic obstetric anesthesia units. Responses were stratified by PPH protocol availability as appropriate. Univariate statistics were used to characterize survey responses and the probability distribution for PPH protocol availability was estimated using the binomial distribution. RESULTS: The survey response rate was 58%. The percentage of responding units with a PPH protocol was lower than hypothesized (P = 0.03); there was a PPH protocol in 67% of responding units (N = 40, 95% confidence interval [CI]: 53%-78%). The median annual delivery volume for responding units with PPH protocol was 3900 vs 2300 for units without PPH protocol (P = 0.002), with no difference in cesarean delivery rate (P = 0.73) or observed PPH rate (P = 0.69). There was no difference in annual delivery volume between responding and nonresponding hospitals (P = 0.06), suggesting that academic centers with delivery volume >3200 births per year are more likely than smaller volume hospitals to have a PPH protocol in place (odds ratio 3.16 (95% CI: 1.01-9.90). Adjusting for delivery volume among nonresponding hospitals, we estimate that 67% (95% CI: 55%-77%) of all academic obstetric anesthesia units had a PPH protocol in place at the time of this survey. Institutional processes for escalation do not correlate with the presence of a PPH protocol. There was a massive transfusion protocol in 95% of units with a PPH protocol and in 90% of units without (95% CI of difference: -7% to 7%). A PPH code team or rapid response team was available in 57% of responding institutions, with no difference between units with or without a PPH protocol [mean difference 4%, 95% CI (-24% to 32%)]. CONCLUSIONS: Despite increasing emphasis on national quality improvement in patient safety, there are no PPH protocols in at least 20% of U.S. academic obstetric anesthesia units. Delivery volume is the most important variable predicting the presence of a PPH protocol. National efforts to ensure universal presence of a PPH protocol in all academic centers will achieve the greatest impact by focusing on small-volume facilities. Future work is needed to evaluate and facilitate PPH implementation in nonacademic obstetric units.

A Case Report of Fluoroscopically Guided Epidural Catheter Placement in a Parturient with History of Tethered Cord, Super-Morbid Obesity, and Risk for Difficult Airway.

Tethered cord syndrome results from adherence of the conus medullaris to the sacrum and may be associated with high complication rates from neuraxial anesthesia. We present the case of a 32-year-old gravida 2 para 0 patient with a history of lipomyelomeningocele (one of several types of spina bifida) and tethered cord status post repair, residual low-lying conus medullaris, supermorbid obesity (body mass index of 58), and Mallampati IV airway, who underwent successful fluoroscopically guided epidural catheter placement for vaginal delivery. Risks and benefits of epidural catheter utilization and methods of placement are reviewed.

Racial and Ethnic Disparities in Receipt of General Anesthesia for Cesarean Delivery.

Importance: General anesthesia for cesarean delivery is associated with increased maternal morbidity, and Black and Hispanic pregnant patients have higher rates of general anesthesia use compared with their non-Hispanic White counterparts. It is unknown whether risk factors and indications for general anesthesia differ among patients of differing race and ethnicity. Objective: To evaluate differences in general anesthesia use for cesarean delivery and the indication for the general anesthetic by race and ethnicity. Design, Setting, and Participants: In this retrospective, cross-sectional, single-center study, electronic medical records for all 35 117 patients who underwent cesarean delivery at Northwestern Medicine's Prentice Women's Hospital from January 1, 2007, to March 2, 2018, were queried for maternal demographics, clinical characteristics, obstetric and anesthetic data, the indication for cesarean delivery, and the indication for general anesthesia when used. Data analysis occurred in August 2023. Exposure: Cesarean delivery. Main Outcomes and Measures: The rate of general anesthesia for cesarean delivery by race and ethnicity. Results: Of the 35 117 patients (median age, 33 years [IQR, 30-36 years]) who underwent cesarean delivery, 1147 (3.3%) received general anesthesia; the rates of general anesthesia were 2.5% for Asian patients (61 of 2422), 5.0% for Black patients (194 of 3895), 3.7% for Hispanic patients (197 of 5305), 2.8% for non-Hispanic White patients (542 of 19 479), and 3.8% (153 of 4016) for all other groups (including those who declined to provide race and ethnicity information) (P < .001). A total of 19 933 pregnant patients (56.8%) were in labor at the time of their cesarean delivery. Of those, 16 363 (82.1%) had neuraxial labor analgesia in situ. Among those who had an epidural catheter in situ, there were no racial or ethnic differences in the rates of general anesthesia use vs neuraxial analgesia use (Asian patients, 34 of 503 [6.8%] vs 1289 of 15 860 [8.1%]; Black patients, 78 of 503 [15.5%] vs 1925 of 15 860 [12.1%]; Hispanic patients, 80 of 503 [15.9%] vs 2415 of 15 860 [15.2%]; non-Hispanic White patients, 255 of 503 [50.7%] vs 8285 of 15 860 [52.2%]; and patients of other race or ethnicity, 56 of 503 [11.1%] vs 1946 of 15 860 [12.3%]; P = .16). Indications for cesarean delivery and for general anesthesia were not different when stratified by race and ethnicity. Conclusions and Relevance: Racial disparities in rates of general anesthesia continue to exist; however, this study suggests that, for laboring patients who had labor epidural catheters in situ, no disparity by race or ethnicity existed. Future studies should address whether disparities in care that occur prior to neuraxial catheter placement are associated with higher rates of general anesthesia among patients from ethnic and racial minority groups.

Prophylactic epidural blood patch after unintentional dural puncture for the prevention of postdural puncture headache in parturients.

Unintentional dural puncture is a source of significant morbidity in obstetric patients undergoing neuraxial anesthesia. In this focused review, we discuss the use of a prophylactic epidural blood patch to prevent postdural puncture headache, particularly as it relates to the obstetric population. Although epidural blood patch is thought to be an effective treatment for postdural puncture headache, there is insufficient evidence to support its use as a prophylactic procedure.

The Generalizability of Patients' Preferences and Concerns regarding Anesthesia Care for Cesarean Delivery: A Prospective Survey.

BACKGROUND: False assumptions regarding the generalizability of patients' expectations and preferences across different demographic groups may contribute in part to the increased prevalence of negative peripartum outcomes seen among women of color. The intention of this study was to determine preferences and concerns regarding anesthesia care during cesarean delivery in a largely African-American population and to compare them to those obtained in a prior study conducted in a demographically distinct population. METHODS: Women presenting for scheduled cesarean delivery or induction of labor completed a preoperative survey requesting demographic information and the opportunity to rank ten common potential anesthetic outcomes in relation to each other from most to least desirable. Participants were also asked about their biggest fear concerning their anesthetic and their preferences and expectations regarding degree of wakefulness, pain, and other adverse events. Those who underwent cesarean delivery were administered a briefer postoperative survey. We tabulated preference rankings and then compared demographic and outcome data to that obtained in a previous study with a demographically dissimilar population. RESULTS: A total of 73 women completed the preoperative survey, and 64 took the postoperative survey. Pain during and after cesarean delivery was ranked as least desirable outcomes and fear of paralysis was respondents' principal concern with neuraxial anesthesia. Postoperative concerns were similar to preoperative concerns and did not correlate with the frequency with which specific adverse outcomes occurred. These results were consistent with those from the previous study despite the women in this study being more likely to be younger, unmarried, African-American, and less educated than those in the previous investigation. CONCLUSIONS: Patient preference rankings and concerns were remarkably similar to those previously demonstrated despite a number of demographic differences between the two populations, suggesting generalizability of these preferences to a broader obstetric population.