The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

COMPARISON OF TWO TEMPERATURES FOR TRANSCUTANEOUS PCO2 MONITORING IN NEONATES

Brandon Kuehne1 ,Melanie Stein2, Leif D. Nelin2



Background: Studies have shown that Transcutaneous monitoring (PtcCO2) is a reliable method for estimating arterial PCO2 (PaCO2) in neonates. Complications of PtcCO2 monitoring include patient skin injury (burns) related to electrode heating. We investigated the reliability of PtcCO2 monitoring using lower electrode temperatures to avoid patient burns.

Methods:
We evaluated two electrode temperatures 40° and 41° C using a Radiometer TINA TCOM. Any neonate with an arterial line in place and an ordered ABG that would be drawn within a time window of 4 hrs was studied. Because the ABGs were ordered independent of the PtcCO2, some patients had more gases drawn within the monitoring window than others. Staff was blinded to the real-time monitoring results in order to prevent any potential bias with relation to drawing the patient's ABG.

Results:
PtcCO2 and PaCO2 results were paired in 15 infants at 4° C (24 pairs) and 13 infants at 41° C (16 pairs). The mean weight of the 40° C group was 1.72 kg ± 1.07 kg and the mean corrected gestational age (CGA) was 32 weeks ± 5.5 weeks. The mean weight of the 41° C group was 2.17 kg ± 1.01 kg and the mean CGA was 34 weeks ± 5 weeks. The paired measurements were analyzed using linear regression. The data were also compared to the line of identity. At both temperatures the PtcCO2 and PaCO2 were significantly correlated (R = 0.57, p<0.005 for 40°C and R=0.92, p<0.0001 for 41°C), however at 41°C there was a better correlation and the points were closer to the line of identity throughout the range of PaCO2 studied than at 40°C.

Conclusions:
Our results suggest that there was a more consistent relationship between paired PaCO2 and PtcCO2 measurements using an electrode temperature of 41° C compared to a temperature of 40° C. These results support the notion that PtcCO2 monitoring can be done effectively using an electrode temperature of 41° C in premature neonates.