Intra-uterine fetal demise caused by amniotic band syndrome after standard amniocentesis

The amniotic band syndrome represents a prime example of exogenous disruption of an otherwise normal feta I development. It may be a sequel of invasive diagnostic procedures such as amniocentesis or fetal blood sampling. A 38-year-old gravida II, para II delivered a morphologically normal male stillborn at term. The pregnancy history had been unremarkable but for an early 2nd-trimester amniocentesis. Cause of the intra-uterine fetal demise was noted to be an amniotic band constricting the umbilical cord, An amniotic band is a rare but potentially fatal condition which may be induced by, e.g., invasive prenatal procedures. Such bands are not usually diagnosed prenatally; however, selected patients with augmented risk may profit from intensive ultrasound evaluation including Doppler studies. Copyright (C) 2000 S. Karger AG, Basel

Sonographic cervical volumetry in higher order multiple gestation

Objective:The aim of this study of multifetal pregnancies was the comparison of three-dimensional (3D) volumetry of the cervix, conventional sonographic cervical length measurement and clinical assessment. Methods 10 mothers were investigated in an observational study between 5/1999 and 9/2000. A total of 34 consecutive 2D-and 3D-transabdominal ultrasound measurements were performed. Results: Volumetry of the cervix was possible in all 34 exams. 2D-cervical length assessment could not be obtained in 6% because the presenting fetal part obstructed the sonographic plane. Both methods allowed equal judgement of the configuration of the cervix. A significant correlation was found between mean 2D-cervical length (28.7 mm, 7.7 SD) and mean cervical volume (30.0 cm(3), 16.0 SD). Parity, subjective preterm labor or need of tocolytics showed no correlation with any biometrical parameter studied. Conclusion: Volumetry was superior for the assessment of cervical biometry and conformation in women when the transabdominal 2D-plane was obstructed. When cervical length was obtainable by a conventional scan, the technically more complex 3D-imaging did not provide further information. Copyright (C) 2001 S. Karger AG, Basel

Correlation of lung collapse and gas exchange

Background: Atelectasis can provoke pulmonary and non-pulmonary complications after general anaesthesia. Unfortunately, there is no instrument to estimate atelectasis and prompt changes of mechanical ventilation during general anaesthesia. Although arterial partial pressure of oxygen (PaO2) and intrapulmonary shunt have both been suggested to correlate with atelectasis, studies yielded inconsistent results. Therefore, we investigated these correlations. Methods: Shunt, PaO2 and atelectasis were measured in 11 sheep and 23 pigs with otherwise normal lungs. In pigs, contrasting measurements were available 12 hours after induction of acute respiratory distress syndrome (ARDS). Atelectasis was calculated by computed tomography relative to total lung mass (Mtotal). We logarithmically transformed PaO2 (lnPaO2) to linearize its relationships with shunt and atelectasis. Data are given as median (interquartile range). Results: Mtotal was 768 (715–884) g in sheep and 543 (503–583) g in pigs. Atelectasis was 26 (16–47)% in sheep and 18 (13–23) % in pigs. PaO2 (FiO2 = 1.0) was 242 (106–414) mmHg in sheep and 480 (437–514) mmHg in pigs. Shunt was 39 (29–51)% in sheep and 15 (11–20) % in pigs. Atelectasis correlated closely with lnPaO2 (R2 = 0.78) and shunt (R2 = 0.79) in sheep (P-values<0.0001). The correlation of atelectasis with lnPaO2 (R2 = 0.63) and shunt (R2 = 0.34) was weaker in pigs, but R2 increased to 0.71 for lnPaO2 and 0.72 for shunt 12 hours after induction of ARDS. In both, sheep and pigs, changes in atelectasis correlated strongly with corresponding changes in lnPaO2 and shunt. Discussion and Conclusion: In lung-healthy sheep, atelectasis correlates closely with lnPaO2 and shunt, when blood gases are measured during ventilation with pure oxygen. In lung-healthy pigs, these correlations were significantly weaker, likely because pigs have stronger hypoxic pulmonary vasoconstriction (HPV) than sheep and humans. Nevertheless, correlations improved also in pigs after blunting of HPV during ARDS. In humans, the observed relationships may aid in assessing anaesthesia-related atelectasis