P.P. van den Berg

The effect of pulsating arteries on reflectance pulse oximetry: measurements in adults and neonates.

Objective. The objective of our study was to describe the results from human experiments during normoxia that demonstrate the effect of pulsating arteries on the measured arterial oxygen saturation (Spo2) using a reflectance pulse oximeter sensor.Methods. In 6 healthy adults and 7 healthy neonates, a Nellcor reflection sensor (FS-10 oxisensor, Nellcor, Inc., Pleasanton, CA) was placed in three different positions: (1) on the forehead, (2) on the temporal area, with the photodiode placed over the superficial temporal artery, and (3) on the temporal area, with the light-emitting diodes (LEDs) placed over the superficial temporal artery.Results. Placement of the sensor in position 2 resulted in a significantly lower Spo2 reading, compared to sensor position 1: 5.8% (p<0.01) lower for adults and 7.5% (p<0.01) lower for neonates. Placement of the sensor in position 3 resulted in significantly larger plethysmographic signals, compared to sensor position 1; but, the Spo2 readings were alike.Conclusions. Pulsating arteries can affect the reliability of reflection pulse oximetry. Depending on the position of the sensor, a falsely low Spo2 value can be observed.

Reflectance Pulse Oximetry

Continuous fetal heart rate (FHR) monitoring is used to assess the fetal condition during labour. Unfortunately, FHR patterns are not always easy to interpret, with low sensitivity and specificity as consequence. Other continuous methods for fetal surveillance have been proposed during labour (e.g. transcutaneous pO2 and pCO2, and pH-monitoring), but are not widespread used.

Cesarean Section Rates and Adverse Neonatal Outcomes After Induction of Labour Versus Expectant Management in Women With an Unripe Cervix: A Secondary Analysis of the HYPITAT and DIGITAT Trials

Objective To evaluate caesarean section and adverse neonatal outcome rates after induction of labour or expectant management in women with an unripe cervix at or near term. Design Secondary analysis of data from two randomised clinical trials. Setting Data were collected in two nationwide Dutch trials. Population Women with hypertensive disease (HYPITAT trial) or suspected fetal growth restriction (DIGITAT trial) and a Bishop score ≤ 6. Methods Comparison of outcomes after induction of labour and expectant management. Main outcome measures Rates of caesarean section and adverse neonatal outcome, defined as 5-minute Apgar score ≤ 6 and/or arterial umbilical cord pH < 7.05 and/or neonatal intensive care unit admission and/or seizures and/or perinatal death. Results Of 1172 included women with an unripe cervix, 572 had induction of labour and 600 had expectant management. We found no significant difference in the overall caesarean rate (difference -1.1%, 95% CI -5.4 to 3.2). Induction of labour did not increase caesarean rates in women with Bishop scores from 3 to 6 (difference -2.7%, 95% CI -7.6 to 2.2) or adverse neonatal outcome rates (difference -1.5%, 95% CI -4.3 to 1.3). However, there was a significant difference in the rates of arterial umbilical cord pH < 7.05 favouring induction (difference -3.2%, 95% CI -5.6 to -0.9). The number needed to treat to prevent one case of umbilical arterial pH < 7.05 was 32. Conclusions We found no evidence that induction of labour increases the caesarean rate or compromises neonatal outcome as compared with expectant management. Concerns over increased risk of failed induction in women with a Bishop score from 3 to 6 seem unwarranted. This article is commented on by WM Gilbert. To view this mini commentary visit http://dx.doi.org/10.1111/1471-0528.14025.