Accuracy of a New Low-flow Sidestream Capnography Technology in Newborns: A Pilot Study

Division of Newborn Medicine, Children's Hospital and Harvard Medical School, Boston, MA, USA.
Journal of Perinatology (Impact Factor: 2.07). 04/2002; 22(3):219-25. DOI: 10.1038/
Source: PubMed


To evaluate the accuracy of a new low-flow sidestream capnography technology and analyze components of the capnogram in mechanically ventilated newborns with and without pulmonary disease.
Twenty patients were prospectively identified. Eligible infants were mechanically ventilated and had an indwelling arterial catheter. Two groups were identified: newborns who were receiving mechanical ventilation for pulmonary diseases, and newborns who were receiving postoperative mechanical ventilation for nonpulmonary conditions. End-tidal CO(2) (PetCO(2)) was measured for 1-minute pre- and post-arterial blood sampling, and PetCO(2) and PaCO(2) were compared for each patient. Eight quantitative waveform parameters were also measured on all patients.
Newborns in the pulmonary group (n=13) (persistent pulmonary hypertension of the newborn/meconium aspiration syndrome, respiratory distress syndrome, pneumonia) and newborns in the control group (n=7) were matched for birth weight, gestational age, and postnatal age. PetCO(2)-PaCO2 Gradient values were higher in the pulmonary group (7.4+/-3.3 mm Hg) than controls (3.4+/-2.4 mm Hg). Four waveform parameters (ascending slope, alveolar angle, alpha angle, descending angle) were identified, which independently differentiated patients with pulmonary disease from controls.
Low-flow capnography with Microstream technology accurately measured alveolar CO(2) in newborns without pulmonary disease, as demonstrated by normal PetCO(2)-PaCO(2) gradients. The measured PetCO(2)-PaCO(2) gradient, as expected, was significantly higher in newborns with pulmonary disease. We also identified four quantitative waveform parameters that may be useful in differentiating between mechanically ventilated newborn patients with and without lung disease.

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Available from: David Zurakowski, Dec 13, 2013
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    • "Because of these prior studies most physicians agree that in the clinical setting of respiratory distress, EtCO2 monitoring is mostly useful in following the trend in ventilatory status and not as a specific correlate to blood gas pCO2.[23,28] However, knowing EtCO2 can serve as a direct corollary to blood gas pCO2 in patients without pulmonary disease[22,25,29], it raises the question of a possible threshold of pulmonary disease that until reached EtCO2 remains an accurate tool to assess blood gas pCO2. "
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    • "In order to record and analyze instantaneous CO2 digitized waveforms, we chose the commercially available Oridion Microcap® CO2 portable bedside capnograph (Oridion Systems Ltd, Microcap®, model #CS-04178) [27]. It uses Microstream® Technology with low-flow, sidestream aspiration vs. traditional high-flow or mainstream monitors [28,29]. This monitor has a low sampling rate of 50 ml/min and an accuracy of EtCO2 readings of ± 2 mmHg in the range of 0–38 mmHg and ± 5% of the reading in the range of 39–99 mmHg, when steady state is reached. "
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