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Sidestream microstream end tidal carbon dioxide measurements and blood gas correlations in neonatal intensive care unit
Author(s) -
Singh Bindya S.,
Gilbert Urquidez,
Singh Sharad,
Govindaswami Balaji
Publication year - 2013
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.22593
Subject(s) - medicine , dead space , capnography , neonatal intensive care unit , tidal volume , anesthesia , carbon dioxide , correlation coefficient , zoology , mechanical ventilation , pediatrics , respiratory system , mathematics , statistics , chemistry , organic chemistry , biology
Objective The study was designed to assess the use of newer sidestream microstream end tidal carbon dioxide (ETCO 2 ) device in predicting blood carbon dioxide (PCO 2 ) measurements in very low birth weight (VLBW = birth weight <1,500 g) and non‐VLBW NICU neonates. Study Design Sidestream microstream ETCO 2 detectors were allowed time to calibrate and reach steady state prior to blood gas measurements. Blood CO 2 (PCO 2 ) and simultaneous ETCO 2 were recorded. Ratio of dead space to tidal volume (VD/VT) was calculated using modified Bohr's equation. Correlation coefficient, estimates of difference, standard deviation, and 95% limits of agreement between ETCO 2 and PCO 2 concentrations were calculated. Results Two hundred eighty‐six paired samples were collected from 48 ventilated NICU patients. Average PCO 2 and ETCO 2 were 58.4 and 50.6 with a correlation of 0.76. Subgroup analysis showed a correlation of 0.73 in 204 paired blood from 34 VLBW infants and 0.82 in 82 paired samples from non‐VLBW infants. Estimates of difference ± standard deviation between PCO 2 and ETCO 2 concentrations in these three groups, respectively (ALL, VLBW, and non‐VLBW) were 7.84 ± 9.96, 8.2 ± 10.16, and 6.95 ± 9.45. The correlation coefficient significantly improved in the VLBW group to 0.86 with dead space to tidal volume ratio (VD/VT) <30% (0.86 vs. 0.42; P < 0.001). Conclusion ETCO 2 measurements using sidestream microstream technology in VLBW demonstrated that the correlation of ETCO 2 and PCO 2 was moderate, but the agreement was less than adequate (bias > 5 mmHg in all groups). The results improved with lower VD/VT, suggesting that sidestream capnography is more reliable in conditions of less severe lung disease. Pediatr Pulmonol. 2013; 48:250–256. © 2012 Wiley Periodicals, Inc.