Williams E, Dassios T, Greenough A. Assessment of sidestream end-tidal capnography in ventilated infants on the neonatal unit.
Pediatr Pulmonol 2020;
55:1468-1473. [PMID:
32187888 DOI:
10.1002/ppul.24738]
[Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/11/2020] [Indexed: 01/13/2023]
Abstract
OBJECTIVES
Continuous monitoring of carbon dioxide (CO2 ) levels can be achieved by capnography. Our aims were to compare the performance of a sidestream capnograph with a low dead space and sampling rate to a mainstream device and evaluate whether its results correlated with arterial/capillary CO2 levels in infants with different respiratory disease severities.
WORKING HYPOTHESES
End-tidal carbon dioxide (EtCO2 ) results by sidestream and mainstream capnography would correlate, but the divergence of EtCO2 and CO2 results would occur in more severe lung disease.
STUDY DESIGN
Prospective cohort study.
PATIENT-SUBJECT SELECTION
Fifty infants with a median (interquartile range) gestational age of 31.1 (27.1-37.4) weeks and birth weight of 1.37 (0.76-2.95) kg.
METHODOLOGY
Concurrent measurements of EtCO2 in ventilated infants were made using a new Microstream sidestream device and a mainstream capnograph (gold standard). Results from both devices were compared with arterial or capillary CO2 levels. The ratio of dead space to tidal volume (Vd/Vt) was calculated to assess respiratory disease severity.
RESULTS
The mean difference between the concurrent measurements of EtCO2 was -0.54 ± 0.67 kPa (95% agreement levels - 1.86 to 0.77 kPa), the correlation between the two was r = .85 (P < .001). Sidestream capnography results correlated better with partial pressure of CO2 (PCO2 ) levels in infants with less (Vd/Vt < 0.35; r2 = .66, P < .001) rather than more severe (Vd/Vt > 0.35; r2 = .33, P = .01) lung disease.
CONCLUSIONS
The sidestream capnography performed similarly to the mainstream capnography. The poorer correlation of EtCO2 to PCO2 levels in infants with severe respiratory disease should highlight to clinicians increased ventilation-perfusion mismatch.
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