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A study on actual trends in obstetric analgesia and anaesthesia was conducted on data received from 385 German departments of obstetrics with a total of 267441 deliveries. On the basis of these extensive data quantitative results could be obtained about analgesic procedures for spontaneous deliveries, operative-vaginal deliveries, Caesarean sections and in cases of foetal or maternal risks. The type of analgesics and local anaesthetics used, their side effects and complications were recorded. In addition the cooperation and interaction between obstetricians and anesthesiologists in practising and monitoring obstetrical analgesia and anaesthesia are described.

The German Society of Gynaecology and Obstetrics has published standards for obstetrical services concerning equipment, personnel and organisation. All obstetrical services must be able to perform an emergency Caesarean section with a 20 minutes interval from decision to delivery (D-D time). This study represents an analysis of the 75 emergency Caesarean sections performed at the University hospital Grosshadern of Munich during the interval from 1987 to 1994. This being a level III hospital, there is a 24 hour obstetrical, anaesthesia and neonatal service, and personnel is readily available. The operation can and has been done in each delivery room. 1. The incidence of emergency Caesarean sections was 0.6% compared to a total Caesarean rate of 21.5% in a high risk population having a preterm rate of 19% during the period of the study. 55% of the patients who had emergency Caesarean sections presented with a gestational age of less than 37 weeks and 35% of less than 32 weeks. 2. The mean time elapsed between decision and delivery (D-D time) was 12.8 minutes; however, the 90 percentile was 22 minutes and exceeded the recommended D-D time of 20 minutes. The mean decision to incision interval represented 9.1 minutes, and 3.6 minutes were needed between incision and delivery. 3. There was a significantly higher frequency of emergency Caesarean sections, performed during daytime and evening hours compared to early morning (0-8 a.m.). However, the D-D time intervals examined for these three time periods showed only minor, non-significant differences. In conclusion, an efficient emergency Caesarean delivery requires a coordinated team effort with excellent cooperation between obstetrics, anaesthesia and neonatology. Our study demonstrates that even in this optimal setting a decision to delivery time within the 20-minute interval can not always be achieved. Based upon our results and other studies, we recommend a D-D time of 30 minutes.

Artifacts may occur in many in vitro models of pulse oximetry due to the optical effects of synchronously oriented and/or deformed erythrocytes. Although these artifacts are most likely negligible in living superficial tissues, they are demonstrated to have considerable influence on the calibration curve obtainable from the in vitro simulation of pulse oximetry in such models, especially at low oxygen saturations. Therefore, we have developed a modified in vitro model which reduces the effect of these artifacts. This is achieved by excluding data obtained during pressure transients and by raising the blood flow velocity. As a result, the model more closely approximates in vivo pulse oximetry, particularly under clinically important conditions of low blood oxygen saturation levels.

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