The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

AGREEMENT BETWEEN TRANSCUTANEOUS AND ARTERIAL CARBON DIOXIDE LEVELS IN A COHORT OF CRITICALLY ILL PEDIATRIC PATIENTS DURING HIGH-FREQUENCY OSCILLATORY VENTILATION.

John R. Priest1, Craig D. Smallwood1, John H. Arnold2,3; 1Department of Respiratory Care, Boston Children’s Hospital, Boston, MA; 2Department of Anesthesia, Boston Children’s Hospital, Boston, MA; 3Harvard Medical School, Boston, MA

Introduction: High-frequency oscillatory ventilation (HFOV) is commonly used to treat patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in the pediatric intensive care unit. Continuous monitoring of ventilation is problematic during HFOV as end-tidal CO2 monitoring and volumetric capnography cannot be applied. Serial arterial blood gas analysis and transcutaneous CO2 (PTCCO2) monitoring are therefore applied. This study was conducted to assess the agreement between PTCCO2) monitoring and arterial partial pressure of CO2 (PaCO2) during HFOV in a cohort of critically ill children. Methods and Materials: A retrospective review of patients aged 1 to 18 years of age who were ventilated using a high-frequency oscillatory ventilator (Carefusion 3100A or 3100B, Yorba Linda, CA) and were continuously monitored using the SenTec Digital Monitoring System (Fenton, MO) from January 2010 to January 2012 was conducted. All arterial blood gas (ABG) data were recorded as well as PTCCO2 levels. MS Excel was used to record data and Prism Graphpad was used to perform analysis. Linear regression and Bland-Altman plotting were used to assess the agreement between PTCCO2 and PaCO2. Results: Nineteen patients were treated with HFOV during the eligibility period. Twelve patients (n=8 female) met inclusion criteria and were included in the analysis. Eight were ventilated with the 3100A and four with the 3100B. The age (mean ± SD), pH, PaCO2, and PTCCO2 were 7.4±6.3 years, 7.335 +0.089, 68.1+16.8, 71+18 respectively. A total of 111 sample sets were included in the analysis. Linear regression analysis revealed a slope of 0.96 and an r2 of 0.80 (p < 0.0001; see Figure 1.). The mean bias was 2.9 mmHg between PaCO2 and PTCCO2 and limits of agreement were -13.1 to 19.0 (See Figure 2.). Conclusion: We found a statistically significant relationship between PTCCO2 and PaCO2; however the limits of agreement were wide. The wide limits may be related to variable perfusion which can adversely effect accuracy. The PTCCO2 monitor is an important noninvasive tool for the clinician to use during the management of ventilation during HFOV. However, serial ABGs remain necessary. Sponsored Research - None