Monitoring of carbon dioxide in ventilated neonates: a prospective observational study.

OBJECTIVE

To assess the reliability, accuracy and precision of distal end-tidal capnography (detCO) in neonates compared with transcutaneous (tcCO) carbon dioxide measurements.

DESIGN

Observational, prospective clinical study.

SETTING

Neonatal intensive care unit at Medical University of Vienna.

PARTICIPANTS

Conventionally ventilated neonates with a body weight between 1000 g and 3000 g.

INTERVENTION

End-tidal partial pressure of CO was measured in distal position using the separate lumen of a double-lumen endotracheal tube connected to an external side-stream capnometer. Three consecutive detCO and tcCO values were recorded simultaneously and compared with simultaneous arterialised partial pressure of CO (paCO) measurements in each patient.

MAIN OUTCOME MEASURES

Reliability, accuracy and precision of detCO and tcCO measurements compared with paCO in neonates.

RESULTS

Twenty-five neonates were included with a median (range) weight at enrolment of 1410 (1010-2980) g, from which 81 simultaneous measurements of detCO, tcCO and paCO were obtained. The mean (SD) of paCO, detCO and tcCO was 45.0 (8.6) mmHg, 42.4 (8.4) mmHg and 50.4 (20.4) mmHg, respectively. The intraclass correlation between paCO and detCO and between paCO and tcCO reached 0.80 (95% CI 0.71 to 0.87, p<0.001) and 0.59 (95% CI 0.43 to 0.72, p<0.001), respectively. In the Bland-Altman analysis, bias and precision of detCO with respect to paCO amounted to -2.68 mmHg and 10.62 mmHg (95% CI 8.49 to 14.51), respectively. Bias and precision of tcCO with respect to paCO amounted to 5.39 mmHg and 17.22 mmHg (95% CI 13.21 to 23.34), respectively.

CONCLUSION

DetCO had better reliability, accuracy and precision with paCO than tcCO in ventilated neonates without severe lung diseas.

TRIAL REGISTRATION NUMBER

NCT03758313.