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Biomedical subjects

P M Molloy

Publications and source records attributed to P M Molloy.

5 recordsLinked to original sources
PubMed1984

Continuous, noninvasive measurement of fetal oxygen and carbon dioxide levels in labor by use of mass spectrometry.

Clinical evaluation of the continuous, simultaneous measurement of fetal scalp surface oxygen and carbon dioxide partial pressures by mass spectrometry was undertaken for 52 labors. The mass spectrometer (MM8-80, V.G. Gas Analysis, Winsford, England) was easy to operate and had good long-term stability. The mean drifts for both oxygen and carbon dioxide over the study periods were less than 2 mm Hg. The mean (+/- SD) cervical dilatation at the time of transducer application was 6.1 (+/- 1.9) cm and the mean (+/- SD) duration of the studies was 169 (+/- 122) minutes; 10.5% of the transducer applications were unsuccessful. Falls in fetal scalp surface oxygen levels and rises in carbon dioxide levels were more frequent with late than with variable and with variable than with early fetal heart rate decelerations and with increasing severity and frequency of decelerations. Fetal scalp surface pressure changes also occurred with fetal heart rate variability changes, including some related to behavioral state changes. There was not a constant reciprocal relationship between oxygen and carbon dioxide changes, and fetal heart rate patterns were not related to actual blood gas levels. Fetal scalp surface measurements were related to both fetal blood sample and umbilical artery results. Trends in both oxygen and carbon dioxide levels during the course of labor were compared and related to other fetal variables, and most of the time the scalp surface measurements were an accurate guide to systemic blood gas levels. Maternal oxygen administration resulted in significant increase in fetal scalp surface oxygen levels, and on two of eight occasions it also led to decreases in fetal carbon dioxide levels. Scalp surface gas measurement by means of mass spectrometry is a powerful new method of intrapartum fetal monitoring, which should increase the precision of fetal surveillance as well as allow the accurate assessment of both established and new methods for optimizing labor and delivery.

Carbon Dioxide↗
PubMed1984

Effect of delays in collection or analysis on the results of umbilical cord blood measurements.

Changes in umbilical cord blood pH, PO2 and PCO2 were measured when blood was stored in preheparinized polyethylene syringes in the refrigerator for up to 6 h after delivery, and when there was delayed sampling up to 1 h after delivery from umbilical cord segments left at room temperature. Blood stored in the refrigerator usually showed a decrease in pH and increases in PO2 and PCO2, but the mean rates of change were small: -0.005 units/h for pH; +0.06 kPa/h for PCO2 and +0.03 kPa/h for PO2. Changes in the three variables in blood collected from umbilical cords up to 1 h after delivery were small and not systematic. Much of the variation was within the limits of accuracy of the ABL-3 (Radiometer) blood-gas analyser. The results showed that while immediate collection and analysis of umbilical cord blood is advisable for the greatest accuracy, it is not essential. As long as the delay is not excessive, the results can still be used as a useful guide to the biochemical condition of an infant at birth.

Blood Preservation↗
PubMed1983

Fetal distress and the condition of newborn infants.

In a prospective audit of the obstetric management of 1210 consecutive deliveries the association was investigated between the need for operative delivery for fetal distress during labour and the condition of the newborn infant. Operative delivery was performed for only 11.5% of the newborn infants with severe acidosis at birth (umbilical artery pH less than 7.12, base deficit greater than 12 mmol (mEq)/1), 24.1% of those with an Apgar score less than 7 at one minute, and 15.8% of those with both severe acidosis and a one minute Apgar score less than 7. Most of the infants delivered operatively were in a vigorous condition at birth and did not have severe acidosis. Fetal blood sampling was done in 4.0% of labours. As none of the fetal blood values were less than 7.20 and only three of the infants sampled in utero suffered severe acidosis at birth, fetal blood sampling would have had to be performed much more often to provide a useful guide to metabolic state at birth. While the large majority of "at risk" fetuses had continuous fetal heart rate monitoring in labour, this had not been provided in 48.7% of the labours of infants with severe acidosis, 38.7% of infants with a one minute Apgar score less than 7, and 47.4% of infants with both severe acidosis and a one minute Apgar score less than 7. Continuous fetal heart rate monitoring was associated with a much higher incidence of operative delivery for fetal distress than was intermittent fetal heart rate auscultation. These results suggest an urgent need to review present methods for assessing the intrapartum condition of the fetus, making the diagnosis of fetal distress, and assessing the condition of the infant at birth.

Acidosis↗
PubMed1982

Birth asphyxia.

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Acidosis, Respiratory↗