Risk factor stratification for urgent and non-urgent transfusion in patients giving birth.

BACKGROUND: A common approach to attempt to reduce maternal morbidity from hemorrhage is to recognize patients at increased risk, and to make advance preparations for possible blood transfusion in these patients. Preparation may consist of a hold clot, type and screen, or crossmatch. Most hospitals, including ours, have pathways or guidelines that lay out which of these preparations should be made at the time a patient is admitted to labor and delivery. These are often based on risk factors for hemorrhage, but don't take into account the probability that transfusion will be needed. The cost effectiveness of performing a type and screen or routine crossmatch on patients admitted for delivery has been questioned. Several studies have shown that the chance of transfusions in individuals giving birth is very low. In terms of the need for routine blood preparation, the need for urgent transfusion is most relevant. This has not been included in studies of transfusion rates. OBJECTIVES: The purpose of this study was to quantify the relative importance of risk factors present on admission for needing a blood transfusion and to develop a formula to define each individual's risk. This could then be used to decide an appropriate level of initial blood preparation for patients at different risk levels. STUDY DESIGN: Risk factors for hemorrhage and the level of transfusion preparation were extracted from the medical records of a cohort of 89,881 patients delivering in an 18-hospital health care system over 40 months. We tabulated the number who required at least one RBC transfusion and the number needing an urgent transfusion- defined as receiving blood during labor or within 4 hours after delivery. Odds ratios for requiring a transfusion were calculated for each risk factor. We then calculated the probability of needing a transfusion for each patient based on their risk factor profile. RESULTS: 643 patients had any transfusion during their hospitalization (0.72 % of deliveries), and 311 had an urgent transfusion (0.35% of deliveries). The calculated probability of needing a transfusion was less than 1% in 87.8% of patients and was greater than 5% in 1.2% of patients. The chance of needing a transfusion was highest for placenta accreta spectrum, admission Hgb <8.0, and placenta previa. A second tier of risk factors included abruption, bleeding with no specific diagnosis, and Hgb between 8.0 and 10.0. CONCLUSION: In our cohort, very few patients received a transfusion. Applying a formula derived from patient- specific risk factors, we found that almost all patients have a very low probability of needing a transfusion, especially an urgent transfusion. Based on these results, we suggest that a hold clot be used except for the highest risk patients or in settings with barriers to procuring blood in the rare case of urgent transfusion need. Making this change would greatly reduce hospital blood bank charges.

Confirmatory Middle Cerebral Artery Doppler Testing in Alloimmunized Patients with Suspected Fetal Anemia.

OBJECTIVE: This article aimed to evaluate pregnancy outcomes when a plan to perform fetal blood sampling (FBS) or delivery was based solely on the first abnormal middle cerebral artery peak velocity (MCA-PV) measurement compared with making a plan after a confirmatory test on a subsequent day. STUDY DESIGN: We performed a descriptive study of pregnancy outcomes including all patients in a single healthcare system with maternal red cell alloimmunization undergoing ultrasound between 2005 and 2017 who had at least one MCA-PV>1.5 multiples of the median (MoM). We excluded patients with any sign of hydrops prior to the index visit or abnormal MCA-PV at>35 weeks. The first exam with a MCA-PV>1.5 MoM was deemed the index visit. RESULTS: Fifty patients were identified. Twenty-one patients underwent intervention (FBS or delivery) based on the first abnormal MCA-PV. Of those, 9 had moderate or severe anemia (positive predictive value [PPV]: 43%), while 12 had mild or no anemia. The other 29 patients underwent a confirmatory MCA test between 2 and 8 days later. Of these, 13 patients had an abnormal confirmatory test and 11 of these underwent FBS and 7 had moderate or severe anemia (PPV: 54%). Sixteen patients undergoing confirmatory MCA Doppler had a normal test on repeat and did not undergo FBS. Of those, none developed moderate or severe anemia. CONCLUSION: A substantial number of patients (55%) had normal MCA-PV testing on repeat, allowing avoidance of invasive testing. Deferring FBS until the abnormal MCA-PV was confirmed was not associated with undetected moderate or severe anemia. KEY POINTS: · False-positive results from MCA-PV Doppler prediction of fetal anemia are common.. · Repeat noninvasive testing is normal in many patients with suspected fetal anemia.. · Invasive fetal testing can often be safely avoided by performing a confirmatory Doppler exam ination..

Emergency-release blood transfusions after postpartum hemorrhage at the Intermountain Healthcare hospitals.

BACKGROUND: Most low-risk obstetric patients do not have crossmatched blood available to treat unexpected postpartum hemorrhage. An emergency-release blood transfusion (ERBT) program is critical for hospitals with obstetrical services. We performed a retrospective analysis of obstetrical ERBTs administered in our multihospital system. DESIGN AND METHODS: We collected data from the past 8 years at all Intermountain Healthcare hospitals on every ERBT after postpartum hemorrhage; logging circumstances, number and type of transfused products, and outcomes. RESULTS: Eighty-nine women received ERBT following 224,035 live births, for an incidence of 3.97 transfused women/10,000 births. The most common causally-associated conditions were: uterine atony (40%), placental abruption/placenta previa (16%), retained placenta (11%), and uterine rupture (5%). The mean number of total units transfused was 7.9 (range 1-76). The mean number of red blood cells (RBCs) transfused was 4.8, the median 4, and SD was ±4.4. Massive transfusion protocols (MTPs) for trauma recommend using a ratio of 1:1:1 or 2:1:1 of RBC:FFP:Platelets, however the ratios varied widely for postpartum hemorrhage. Only 1.5% received a 1:1:1 ratio and 7.5% received a 2:1:1 ratio. Nineteen percent (17/89) of women underwent hysterectomy, 7% (6/89) had uterine artery embolization, 36% (32/89) had an intensive care unit admission, and 1% (1/89) died. CONCLUSION: Emergency transfusion for postpartum hemorrhage occurred after 1/2500 births. Most women received less FFP and platelets than recommended for traumatic hemorrhage. A potentially better practice for postpartum hemorrhage would be a balanced ratio of blood products, transfusion of low-titer, group O, cold-stored, whole blood, or inclusion in a MTP.

Unusual Circumstances and Additional Procedures for Fetal Evaluation in Labor.

This chapter describes several circumstances in which the interpretation of the intrapartum fetal heart rate pattern falls outside the usual frame of reference. This includes a more extensive discussion of causes of tachycardia and bradycardia. Ways in which a fetal dysrhythmia may manifest itself in the context of heart rate monitoring are described. Finally, the chapter reviews technological innovations designed to clarify the fetal status when compromise is suspected from the fetal heart rate pattern.

Anticipatory Corticosteroid Administration to Asymptomatic Women with a Short Cervix.

OBJECTIVE: A short cervix is an important risk factor for spontaneous preterm birth. There is substantial evidence that antenatal exposure to corticosteroids significantly benefits infants that are born when delivery occurs between 24 and 34 weeks' gestation and after 48 hours but within 7 days of their administration. Our study was to evaluate whether asymptomatic women who are given a course of antenatal corticosteroids (ACS) at the time a short cervix is identified deliver within the window of proven steroid benefit. STUDY DESIGN: This was a retrospective chart review of patients who had a cervical length of < 2.5 cm between 23 and 34 weeks and who did not have cervical dilation or significant symptoms of preterm labor. RESULTS: Of 367 asymptomatic patients with a short cervix, only two (0.5%) delivered within 7 days of the time a short cervix was identified. With a policy of giving ACS at the time an ultrasound shows a short cervix, 184 patients would have to be treated for each one who realizes a steroid benefit by delivering within 7 days. CONCLUSION: We conclude that unless future studies show that neonates benefit from ACS given more than 7 days before delivery, giving ACS to asymptomatic women solely because the cervix is short is not advised.

Interobserver variability of sonography for prediction of placenta accreta.

OBJECTIVES: The sensitivity of sonography to predict accreta has been reported as higher than 90%. However, most studies are from single expert investigators. Our objective was to analyze interobserver variability of sonography for prediction of placenta accreta. METHODS: Patients with previa with and without accreta were ascertained, and images with placental views were collected, deidentified, and placed in random sequence. Three radiologists and 3 maternal-fetal medicine specialists interpreted each study for the presence of accreta and specific findings reported to be associated with its diagnosis. Investigator-specific sensitivity, specificity, and accuracy were calculated. κ statistics were used to assess variability between individuals and types of investigators. RESULTS: A total of 229 sonographic studies from 55 patients with accreta and 56 control patients were examined. Accuracy ranged from 55.9% to 76.4%. Of imaging studies yielding diagnoses, sensitivity ranged from 53.4% to 74.4%, and specificity ranged from 70.8% to 94.8%. Overall interobserver agreement was moderate (mean κ ± SD = 0.47 ± 0.12). κ values between pairs of investigators ranged from 0.32 (fair agreement) to 0.73 (substantial agreement). Average individual agreement ranged from fair (κ = 0.35) to moderate (κ = 0.53). CONCLUSIONS: Blinded from clinical data, sonography has significant interobserver variability for the diagnosis of placenta accreta.

Extracorporeal life support in patients with congenital diaphragmatic hernia: how long should we treat?

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a frequently lethal birth defect and, despite advances, extracorporeal life support (ie, extracorporeal membrane oxygenation [ECMO]) is commonly required for severely affected patients. Published data suggest that CDH survival after 2 weeks on ECMO is poor. Many centers limit duration of ECMO support. STUDY DESIGN: We conducted a single-institution retrospective review of 19 years of CDH patients treated with ECMO, designed to evaluate which factors affect survival and duration of ECMO and define how long patients should be supported. RESULTS: Of two hundred and forty consecutive CDH patients without lethal associated anomalies, 96 were treated with ECMO and 72 (75%) survived. Eighty required a single run of ECMO and 65 survived (81%), 16 required a second ECMO run and 7 survived (44%). Of patients still on ECMO at 2 weeks, 56% survived, at 3 weeks 46% survived, and at 4 weeks, 43% of patients still on ECMO survived to discharge. After 5 weeks of ECMO, survival had dropped to 15%, and after 40 days of ECMO support there were no survivors. Apgar score at 1 minute, Apgar score at 5 minutes, and Congenital Diaphragmatic Hernia Study Group predicted survival all correlated with survival on ECMO, need for second ECMO, and duration of ECMO. Lung-to-head ratio also correlated with duration of ECMO. All survivors were discharged breathing spontaneously with no support other than nasal cannula oxygen if needed. CONCLUSIONS: In patients with severe CDH, improvement in pulmonary function sufficient to wean from ECMO can take 4 weeks or longer, and might require a second ECMO run. Pulmonary outcomes in these CDH patients can still be excellent, and the assignment of arbitrary ECMO treatment durations <4 weeks should be avoided.

Accuracy of ultrasound for the prediction of placenta accreta.

OBJECTIVE: Ultrasound has been reported to be greater than 90% sensitive for the diagnosis of accreta. Prior studies may be subject to bias because of single expert observers, suspicion for accreta, and knowledge of risk factors. We aimed to assess the accuracy of ultrasound for the prediction of accreta. STUDY DESIGN: Patients with accreta at a single academic center were matched to patients with placenta previa, but no accreta, by year of delivery. Ultrasound studies with views of the placenta were collected, deidentified, blinded to clinical history, and placed in random sequence. Six investigators prospectively interpreted each study for the presence of accreta and findings reported to be associated with its diagnosis. Sensitivity, specificity, positive predictive, negative predictive value, and accuracy were calculated. Characteristics of accurate findings were compared using univariate and multivariate analyses. RESULTS: Six investigators examined 229 ultrasound studies from 55 patients with accreta and 56 controls for 1374 independent observations. 1205/1374 (87.7% overall, 90% controls, 84.9% cases) studies were given a diagnosis. There were 371 (27.0%) true positives; 81 (5.9%) false positives; 533 (38.8%) true negatives, 220 (16.0%) false negatives, and 169 (12.3%) with uncertain diagnosis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 53.5%, 88.0%, 82.1%, 64.8%, and 64.8%, respectively. In multivariate analysis, true positives were more likely to have placental lacunae (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.4-1.6), loss of retroplacental clear space (OR, 2.4; 95% CI, 1.1-4.9), or abnormalities on color Doppler (OR, 2.1; 95% CI, 1.8-2.4). CONCLUSION: Ultrasound for the prediction of placenta accreta may not be as sensitive as previously described.

Fetal umbilical vein deviation in congenital diaphragmatic hernia.

OBJECTIVES: Deviation of the intra-abdominal umbilical vein has been described as a marker of congenital diaphragmatic hernia (CDH) and has been shown to help identify liver herniation into the fetal chest. The purpose of this study was to quantify the degree of deviation in affected fetuses and to determine the accuracy of measurements for diagnosing liver herniation. METHODS: In patients undergoing prenatal sonography for CDH, the midhepatic portion of the umbilical vein was identified, and the distance between the lateral edge of the vein and the inner rib margin was measured. The same was done on the right, and the ratio of the left to right measurement was termed the "umbilical vein ratio." The accuracy of the umbilical vein ratio for predicting the presence and side of the hernia and for diagnosing liver herniation was determined. RESULTS: All but 1 of the cases with right-sided hernias had an umbilical vein ratio above the normal range, and all had liver herniation. Of those with a left-sided hernia, only 2 had a ratio within the normal range. Of those with a left-sided hernia, an umbilical vein ratio less than 0.4 was shown by receiver operating characteristic curve analysis to be the best predictor of liver herniation. This cutoff had sensitivity of 89% for predicting herniation, with a false-positive rate of 14%. CONCLUSIONS: Ninety-three percent of right-sided CDH lesions and 98% of left-sided lesions have an umbilical vein ratio outside the normal range. This finding shows that deviation may a useful indicator of CDH in screening ultrasound examinations. An umbilical vein ratio less than 0.4 is predictive of liver herniation.