Changes in Arterial Blood Gas in Crying Neonates

Kim, Yeo Hyang; Kim, Heng Mi

Abstract

PURPOSE: Arterial blood gas and pH measurements are the standard by which adequacy of oxygenation and ventilation are assessed. The major problem with arterial punctures is that they can rarely be done without disturbing the neonates. Crying during arterial puncture usually results in change in respiratory patten and thus may result in significant changes in blood gas values.
METHODS
Fifteen neonates admitted to NICU during Jan. to Aug. 1997 with pre-existing arterial lines undergoing arterial puncture for blood culture were studied. Only the neonates who cried vigorously during procedure were selected. Neonates were monitored for O2 saturation by pulse oximeter, for heart rate, respiratory rate and non-invasive blood pressure before and during crying. Arterial blood obtained through arterial lines before crying and arterial blood obtained on crying induced by arterial punctures were analyzed. Vital signs, O2 saturation by pulse oximeter before and during arterial punctures were also evaluated. Body weight of the baby patients examined was 1,750-3,090g, gestational age was 34-42 weeks and blood-sampling was performed during the 1st week of life.
RESULTS
In the analysis of arterial blood, all data obtained before and during crying were in normal range. Crying decreased PaCO2 38.6+/-5.6mmHg into 30.6+/-6.7mmHg(P<0.05), HCO3 2.8+/-2.1mmol/L into 19.5+/-3.0mmol/L(P<0.01), and O2 saturation 95.1+/-5.6% into 91.0+/-5.6%(P<0.05), respectively. O2 saturation by pulse oximeter also diminished from 98.3+/-3.1% to 88.8+/-7.8%(P< 0.05) during crying.
CONCLUSION
The results of this study imply that blood gases obtained by intermittent arterial punctures may provide data that do not accurately reflect the neonates' respiratory status.