Obstetric hemorrhage survey: Attitudes and practices of maternal-fetal medicine fellows.

OBJECTIVE: To evaluate experiences related to obstetric hemorrhage and suspected abnormal placentation among first year maternal-fetal medicine fellows. STUDY DESIGN: A cross-sectional anonymous survey was administered at the Society for Maternal-Fetal Medicine fellow retreat in March 2013. Fellows were asked about management strategies that reflected both their individual and institutional practices. RESULTS: There was a 56% response rate (55/98). In cases of postpartum hemorrhage due to uterine atony, there was variable use of the uterine tamponade device. The median incremental time for balloon deflation was every 5 hours (IQR = 2-12). Compared to the east coast, fellows from the west coast performed more hysterectomies (mean±SD; 2.9±2.4 vs. 1.2±1.2, p = 0.004). During a peripartum hysterectomy, 29% of fellows used a handheld cautery device such as Ligasure® or Gyrus®. Fifty-six percent responded that their institution never recommend planned delayed hysterectomies for abnormal placental implantation. CONCLUSION: There is wide variation in practice among first year maternal-fetal medicine fellows in management of peripartum hysterectomy and postpartum hemorrhage.

Detection of pericentric inversion of X chromosome in a male fetus.

Amniocentesis on a 32-year-old woman at risk for trisomy 21 by maternal serum triple screen showed a 46,Y,inv(X) (p22.1q24) karyotype in all cells analyzed. A blood sample was obtained from the mother for cytogenetic evaluation. Since she had the same inversion, DNA replication studies were performed to determine if the X inactivation pattern was random or not, since skewed inactivation of the inverted X might suggest that the breakpoints disrupted functional genes. DNA replication studies demonstrated that 68% of mother's cells with the inverted X were active, suggesting random X inactivation. The random X inactivation pattern suggested that the inversion is probably balanced and should not affect the fetus. A normal male was delivered at 40 weeks gestation.

Peak expiratory flow rate in normal pregnancy.

OBJECTIVE: To determine whether peak expiratory flow rate changes with pregnancy and advancing gestation. METHODS: We measured the peak expiratory flow rate in 57 women during each trimester of pregnancy and postpartum. During four visits, all subjects exhaled forcefully three times into a peak flow meter. For each visit, the best of three attempts defined their peak expiratory flow rate. Using accepted standard nomograms, we normalized peak expiratory flow rate with respect to height and age. Using analysis of variance, we compared the mean normalized peak expiratory flow rates in each of the trimesters and postpartum. RESULTS: The subjects' peak expiratory flow rates did not change significantly during the three trimesters and postpartum (P = .317). The mean peak expiratory flow rates for the three trimesters and postpartum were 434 +/- 18, 452 +/- 16, 444 +/- 15, and 450 +/- 16 (values in liters per minute +/- 95% confidence intervals [CIs]). The mean normalized peak expiratory flow rates for the three trimesters and postpartum were 0.92 +/- 0.036, 0.95 +/- 0.032, 0.94 +/- 0.030, and 0.95 +/- 0.031 (values +/- 95% CI). CONCLUSIONS: This study demonstrates that peak expiratory flow rate does not change with pregnancy and advancing gestation. Therefore, testing peak expiratory flow rate in pregnancy is valid, and physicians can use peak expiratory flow rate accurately and reliably in the management of pregnant women with asthma.

Pharmacokinetics and pharmacodynamics of subcutaneous heparin during the early third trimester of pregnancy.

OBJECTIVE: Our purpose was to study the pharmacokinetics and pharmacodynamics of heparin administered subcutaneously during the early third trimester of pregnancy. STUDY DESIGN: We gave subcutaneous heparin (143 units/kg) to six pregnant women (mean gestational age 27.1 +/- 1.2 weeks) and to six women who were not pregnant, who served as controls. We serially measured plasma heparin concentrations and activated partial thromboplastin times over 10 hours and compared the time courses of these two measures in the two groups. We calculated the mean peak plasma heparin concentration, time to peak plasma heparin concentration, peak activated partial thromboplastin time, and time to peak activated partial thromboplastin time and compared these variables in the two groups. RESULTS: Plasma heparin concentrations changed significantly over time in both pregnant and nonpregnant subjects. However, the peak plasma heparin concentration in pregnant subjects was significantly lower than in controls (0.11 +/- 0.017 units/ml vs 0.23 +/- 0.036 units/ml) and the time to peak plasma heparin concentration was significantly shorter in the pregnant patients compared with the nonpregnant controls (113 +/- 20 minutes vs 222 +/- 20 minutes). The peak activated partial thromboplastin time (30.3 +/- 1.7 seconds) was significantly lower and time to peak activated partial thromboplastin time (137 +/- 31 minutes) significantly shorter in the pregnant women compared with nonpregnant controls (50 +/- 4.0 seconds; 230 +/- 26 minutes). CONCLUSIONS: Subcutaneous administration of heparin to pregnant patients results in lower plasma heparin concentrations and clinically insignificant prolongation of the activated partial thromboplastin time compared with equivalent doses administered to nonpregnant women. These findings have important implications for the dosing and monitoring of subcutaneous heparin in pregnant women.

Comparison of lung sounds and gas trapping in the study of airway mechanics.

We have previously shown that gas is trapped in isolated animal lungs and have proposed that this gas-trapping process is related to meniscus formation in the small airways of the lung. The purpose of this investigation was to compare how the lung sound-generation process and the gas-trapping process are related to airway mechanics and each other. Rats were anesthetized, the heart and lungs were removed en bloc and placed in a liquid-filled plethysmograph. Lung sounds were recorded by using a microphone acoustically coupled to the tracheal cannula. The results show that discontinuous lung sounds in the form of crackles occur during lung inflation at the same time gas trapping takes place.