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An in vitro validation of a commercially available metabolic cart using pediatric ventilator volumes
Author(s) -
Webster Patricia A.,
King Sandra E.,
Torres Adalberto
Publication year - 1998
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/(sici)1099-0496(199812)26:6<405::aid-ppul5>3.0.co;2-r
Subject(s) - reproducibility , medicine , carbon dioxide , dilution , anesthesia , tidal volume , oxygen , confidence interval , ventilation (architecture) , respiratory system , chromatography , chemistry , mechanical engineering , physics , organic chemistry , engineering , thermodynamics
Our objective was to determine the validity of the SensorMedics 2900 Metabolic Measurement Cart® (SensorMedics Corp., Yorba Linda, CA) for use at pediatric ventilator volumes by designing an in vitro validation study. The study was performed using a previously described nitrogen dilution, carbon dioxide infusion technique in which known amounts of nitrogen (N 2 ) and carbon dioxide (CO 2 ) are infused while a test lung is ventilated. Metabolic measurements were made at tidal volumes (V t ) varying from 50–500 mL at a peak end‐expiratory pressure (PEEP) of 0 and 12 cm H 2 O and at inspiratory oxygen fractions (F i,O 2s) ranging from 0.21–0.60. Each study was repeated six times to assess reproducibility of measurements. At a PEEP of 0 cm H 2 O, the measurement of oxygen consumption (V′ O 2), carbon dioxide production (V′ CO 2), and minute ventilation (V′ E ) were all within ±10% of predicted values at all F i,O 2s except when Vt t was 50 mL. When PEEP was increased to 12 cm H 2 O, error in measurement of V′ O 2increased and became unacceptably large as F i,O 2was increased. Each study consisted of six trials, and results showed acceptable reproducibility as demonstrated by narrow 95% confidence intervals. For V t s of 100–500 mL, the metabolic monitor provided accurate and reproducible results under in vitro testing conditions when PEEP was low. Accurate results could not be obtained with a V t of 50 mL or at elevated PEEP. Pediatr Pulmonol. 1998; 26:405–411. © 1998 Wiley‐Liss, Inc.