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Objective: The bias of capnometry (ETCO2) and venous carbon dioxide (vpCO2) among pediatric emergency department (PED) patients triaged to critical care areas is unknown. We aimed to explore correlations and bias between ETCO2 and vpCO2¸and identify predictors of bias. Methods: This was an observational, video-based, retrospective study comparing ETCO2 and vpCO2. Pediatric patients with simultaneous ETCO2 and vpCO2 data were included. Our primary aim utilized linear regressions to determine correlations and Bland-Altman analysis to assess bias. Our secondary aim utilized multiple regression to identify clinical covariates contributing to bias. Covariates included age, respiratory rate, heart rate, mean arterial blood pressure, capnometry interface, PED diagnosis, and PED disposition. Results: A total of 200 PED patients with ETCO2 and vpCO2 data were included. The median (interquartile range [IQR]) ETCO2, vpCO2, and ΔCO2 in mmHg were 38 (32, 46), 49 (41, 61), and 11 (4, 20), respectively. ETCO2 (r = 0.76) and ΔCO2 (r = 0.71) were highly correlated with vpCO2. The mean bias between ETCO2 and vpCO2 was -14.1 mmHg (95% confidence interval [CI], -41.9 -13.7). The bias between ETCO2 and vpCO2 increased at higher values of each measure. ETCO2 sampling interface was the only independent predictor of vpCO2 in our multivariate analysis. Patients requiring bag-valve mask (BVM) ventilation had the highest median bias between ETCO2 and vpCO2 (29 mmHg, IQR 15, 37). Conclusion: ETCO2 and vpCO2 were highly correlated. However, bias increased at higher levels of both ETCO2 and vpCO2. Among PED patients, ETCO2's ability to approximate vpCO2 diminishes with worsening hypercarbic respiratory failure.
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OBJECTIVE: The emergent evaluation of children with suspected traumatic cervical spine injuries (CSI) remains a challenge. Pediatric clinical pathways have been developed to stratify the risk of CSI and guide computed tomography (CT) utilization. The cost-effectiveness of their application has not been evaluated. Our objective was to examine the cost-effectiveness of three common strategies for the evaluation of children with suspected CSI after blunt injury. METHODS: We developed a decision analytic model comparing these strategies to estimate clinical outcomes and costs for a hypothetical population of 0-17 year old patients with blunt neck trauma. Strategies included: 1) clinical pathway to stratify risk using NEXUS criteria and determine need for diagnostic testing; 2) screening radiographs as a first diagnostic; and 3) immediate CT scanning for all patients. We measured effectiveness with quality-adjusted life years (QALYs), and costs with 2018 U.S. dollars. Costs and effectiveness were discounted at 3% per year. RESULTS: The use of the clinical pathway results in a gain of 0.04 QALYs and a cost saving of $2800 compared with immediate CT scanning of all patients. Use of the clinical pathway was less costly and more effective than immediate CT scan as long as the sensitivity of the clinical prediction rule was greater than 87% and when the sensitivity of x-ray was greater than 84%. CONCLUSION: A strategy using a clinical pathway to first stratify risk before further diagnostic testing was less costly and more effective than either performing CT scanning or screening cervical radiographs on all patients.