Performance of capnometry in non-intubated infants in the pediatric intensive care unit

Abstract

BackgroundAssessing the ventilatory status of non-intubated infants in the Pediatric Intensive Care Unit (PICU) is a constant challenge. Methods to evaluate ventilation include arterial blood gas analysis (ABG), which is invasive and intermittent, and transcutaneous carbon dioxide monitoring (PtcCO2), which, while non-invasive, is also intermittent. A method that is non-invasive and continuous would be of great benefit in this population. We hypothesized that non-invasive capnometry via sidestream monitoring of exhaled carbon dioxide (CO2) would provide an acceptable measurement of ventilatory status when compared to ABG or PtcCO2.MethodsPreliminary prospective study of infants less than one year of age admitted to the PICU in a large urban teaching hospital. Infants not intubated and not requiring non-invasive ventilation were eligible. A sidestream CO2 reading was obtained in a convenience sample of 39 patients. A simultaneous ABG was collected in those with an arterial catheter, and a PtcCO2 was obtained in those without.ResultsCorrelation of sidestream CO2 with ABG was excellent (r2 = 0.907). Sidestream correlated less well with PtcCO2 (r2 = 0.649). Results were not significantly altered when weight and respiratory rate were added as independent variables. Bland-Altman analysis revealed a bias of -2.7 with a precision of ±6.5 when comparing sidestream CO2 to ABG, and a bias of -1.7 with a precision of ±9.9 when comparing sidestream CO2 to PtcCO2.ConclusionsPerformance of sidestream monitoring of exhaled CO2 is acceptable clinical trending to assess the effectiveness of ventilation in non-intubated infants in the PICU.

Acoustic method respiratory rate monitoring is useful in patients under intravenous anesthesia

“…Several respiratory rate monitoring techniques are available. Capnography using a nasal or facial interface is a useful technique [13][14][15]. Recently, the acoustic method for respiratory rate monitoring has been used in post-anesthesia care units, intensive care units, and in the operating room under laryngeal mask airway general anesthesia [4,5,[16][17][18].…”

Cardiorespiratory parameters in newborns during sedation with chloral hydrate

“…3,10 The increase in ETCO 2 to an average of 30 mmHg and to a maximum of 38 mmHg with a decrease of respiratory rate from 61 to 51 breaths per minute in our study may indicate bradypneic hypoventilation. 18,19,26 However, it is important to note that we measured only basal ETCO 2 and that our results do not provide information on the percentages of time during which ETCO 2 was above the expected levels. The equipment we used also does not allow quantitative measurement of tidal voulmes.…”

“…We also investigated the impact of chloral hydrate on the noninvasively measured ETCO 2 , which has been shown to be an accurate measure of ventilation in nonintubated newborns with normal respiratory function. [18][19][20] Changes of ETCO 2 during sedation with chloral hydrate have previously only been investigated in two retrospective studies, both of which included older children. 3,10 The increase in ETCO 2 to an average of 30 mmHg and to a maximum of 38 mmHg with a decrease of respiratory rate from 61 to 51 breaths per minute in our study may indicate bradypneic hypoventilation.…”

“…The noninvasive side-stream capnometry through nasal cannulas has previously been proven to be an accurate method for estimating ETCO 2 in nonintubated newborns without pulmonary disease. [18][19][20]…”

Noninvasive Monitoring of Oxygen and Ventilation

“…Continuous monitoring of P ETCO 2 can be useful to ensure adequate ventilation in both mechanically supported and spontaneously breathing patients. [11][12][13] In healthy children, the expected gradient between P ETCO 2 and P aCO 2 is 2-5 mm Hg. A common misconception is that during critical illness, P ETCO 2 ceases to correlate with P aCO 2 , particularly in severely ill patients.…”