Abstract
Objective. To evaluate a new technical equipment for continuous recording of human fetal scalp temperature in labor. Design. Experimental animal study. Methods. Two temperature sensors were placed subcutaneously and intracranially on the forehead of 10 fetal lambs and connected to a temperature monitoring system. The system records temperatures simultaneously on-line and stores data to be analyzed off-line. Throughout the experiment, the fetus was oxygenated via the umbilical cord circulation. Asphyxia was induced by intermittent cord compression, as assessed by pH in jugular vein blood. The intracranial (ICT) and subcutaneous (SCT) temperatures were compared with simple and polynomial regression analyses. Main outcome measures. Absolute and delta ICT and SCT changes. Results. ICT and SCT were both successfully recorded in all 10 cases. With increasing acidosis, the temperatures decreased. The correlation coefficient between ICT and SCT had a range of 0.76–0.97 (median 0.88) by simple linear regression and 0.80–0.99 (median 0.89) by second grade polynomial regression. After an initial system stabilization period of 10 minutes, the delta temperature values (ICT minus SCT) were less than 1.5°C throughout the experiment in all but one case. Conclusions. The fetal forehead SCT mirrored the ICT closely, with the ICT being higher.
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Acknowledgements
The authors thank Ingela Mattisson-Sandström for expert assistance in the animal experiments, Roger Hansson and Calle Stenberg at Medexa Diagnostisk Service AB for technical support, and Håkan Sandsten for valuable advice. This study was supported by grant No. 7980 from the Swedish Medical Research Council, by grants to researchers in the Public Health Service from the Swedish Government, Region Skåne, General Maternity Hospital Foundation, The Gorthon Foundation, The Zoéga Foundation, and The Segerfalk Foundation.
Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.