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Abstract
Accurate records of cord blood gas samples may be important but analysis of samples may be delayed post delivery due to logistical constraints. Cord blood gas samples are stable within isolated segments of cord for up to an hour after delivery, but it is not known how stable cord samples are once taken from an isolated cord segment and refrigerated for several hours. To answer this question we took paired (arterial and venous) cord blood gas samples into standard pre-heparinised syringes (RapidLyte, Siemens Healthcare Diagnostics) at delivery of randomly selected babies and put them in a domestic type refrigerator on the delivery suite (maintained at 4°C). At time intervals up to 7.5 h later, samples were analysed using a blood gas analyser (Bayer RapidLab 840).
Results Arterial and venous pH fell by a maximum of 0.05 pH units (regression line y=−0.0001x, −0.0001x respectively) after 7.5 h. Arterial and venous base deficit rose by a maximum of approximately 3 mmol/l after 7.5 h (regression line y=0.0066x, 0.0065x respectively).
Conclusion Cord gas samples stored at 4°C are relatively stable, and measurements do not change to any significant degree, for up to 7.5 h after collection from cord segments isolated at delivery.