The exciting future of pediatric capnography
In order to keep the concentration in equilibrium, the body must eliminate the carbon dioxide (via exhalation) as fast as it is created. Eliminating it too quickly or allowing the concentration to build can produce serious consequences.
Use of pediatric capnography
In a simulated model of ETT dislodgement in a pediatric patient, rescuers using capnography were able to correct dislodgement before the patient suffered significant reductions in oxygen saturation (Langhan et al., 2011).
EMS personnel must recognize that false positives do occur. For example, it is possible that rescuers can insufflate a child’s stomach with a sufficient quantity of exhaled air (mouth-to-mask) to initially produce a capnography waveform with inadvertent esophageal tube placement. However, subsequent assisted-ventilations should produce a smaller and smaller waveform until the waveforms eventually disappear within five or six breaths.
Therefore, rescuers must verify the presence of the capnography waveform upon initial tube placement and to assure that waveform remains throughout the subsequent resuscitation attempt.
Weak EtCO2 signal from an incomplete endotracheal seal
Benefits of EtCO2 monitoring in cardiac arrest
The guidelines further note that capnography may be beneficial for determining the quality of chest compressions during cardiopulmonary resuscitation (CPR) (Kleinman et al., 2010). Chest compression quality is a major determinate of resuscitation success (Ristagno et al., 2007).
Almost two decades ago, researchers using a canine model of pediatric cardiac arrest found a significant correlation between colorimetric CO2 displays and capnometry measurement (Bhende, Karasic, & Menegazzi, 1995). Further analysis in a series of 40 children between the ages of 1 week and 10 years demonstrated that return of spontaneous circulation (ROSC) resulted in appreciable increases in expired-breath CO2 concentrations (Bhende & Thompson, 1995).
Consistently low ETCO2 readings during the initial moments of the resuscitation attempt could reflect less than optimal CPR quality and suggests the rescuer should focus on efforts to improve chest compressions. Adult research indicates an abrupt and sustained increase in ETCO2 readings just before rescuers can clinically identify ROSC (Pokorna et al., 2010).
Does using EtCO2 strengthen diagnostic impression?
There is little question that capnography produces a unique waveform in the presence of bronchospasm. With effective therapy, this characteristic pattern returns to normal. Rescuers trained in waveform recognition can gauge the effectiveness of their treatment based on changes in the waveform.
However, an ED evaluation of children suffering from acute exacerbations of asthma found that although feasible, capnography monitoring correlated poorly with standard measures of bronchospasm, such as pulmonary index, one-minute forced expiratory volume, and peak expiratory flow rate (Evered, Ducharme, Davis, & Pusic, 2003).
Further, researchers could not demonstrate a statistically significant correlation between initial capnography measurements and the need for hospital admission in children younger than 24 months with clinical evidence of bronchiolitis (Lashkeri, Howell, & Place, 2012).
Similarly, researchers at a freestanding tertiary children’s hospital in Alabama could not quantify ETCO2 values with asthma severity in children between the ages of 3 and 17 years (Guthrie, Adler, & Powell, 2007).
Areas of promise for EtCO2 use
A retrospective review of children admitted to the intermediate care unit for DKA at Children’s Hospital Boston demonstrated a strong correlation between ETCO2 readings and the degree of acidosis (Agus, Alexander, & Mantell, 2006). Researchers could not find a significant correlation between elevated blood glucose values and the presence of metabolic acidosis in pediatric patients with a history of Type I diabetes (Gilhotra & Porte, 2007).
However, they were able to demonstrate that no patient with an eventual diagnosis of diabetic ketoacidosis (DKA) had an ETCO2 reading greater than 30 mm Hg suggesting that, when combined with traditional assessment techniques, nasal capnography may be a more accurate predictor of the presence of DKA than blood glucose values.
In an evaluation of young children (mean age 4 years) who presented to the emergency department with symptoms consistent with gastroenteritis, ETCO2 measurement highly correlates with serum bicarbonate levels suggesting that capnography could be used as a non-invasive measure of acidosis (Nagler, Wright, & Krauss, 2006).
Strong medical direction, strict protocols, and active continuous quality improvement programs are needed to ensure its proper use. Capnography may drastically alter the future care provided for intubated patients, patients in respiratory distress, and children who suffer out-of-hospital cardiac arrest.
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Bhende, M. S., & Thompson, A. E. (1995). Evaluation of an end-tidal CO2 detector during pediatric cardiopulmonary resuscitation. Pediatrics, 95(3), 395–399.
Evered, L., Ducharme, F., Davis, G. M., & Pusic, M. (2003). Can we assess asthma severity using expiratory capnography in a pediatric emergency department? Canadian Journal of Emergency Medicine, 5(3), 169-170.
Fearon, D. M., & Steele, D. W. (2002). End-tidal carbon dioxide predicts the presence and severity of acidosis in children with diabetes. Academic Emergency Medicine, 9(12), 1373–1378. doi:10.1197/aemj.9.12.1373
Garcia, E., Abramo, T. J., Okada, P., Guzman, D. D., Reisch, J. S., & Wiebe, R. A. (2003). Capnometry for non-invasive continuous monitoring of metabolic status in pediatric diabetic ketoacidosis. Critical Care Medicine, 31(10), 2539–2543. doi:10.1097/01.CCM.0000090008.79790.A7
Gilhotra, Y., & Porte, P. (2007). Predicting diabetic ketoacidosis in children by measuring end-tidal CO2 via non-invasive nasal capnography. Journal of Paediatrics and Child Health, 43(), 677–680. doi:10.1111/j.1440-1754.2007.01186.x
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Kleinman, M. E., Chameides, L., Schexnayder, S. M., Samson, R. A., Hazinski, M. F., Atkins, D. L., Berg, M. B., de Caen, A. R., Fink, E. L., Freid, E. B., Hickey, R. W., Marino, B. S., Nadkarni, V. M., Proctor, L. T., Qureshi, F. A., Sartorelli, K., Topjian, A., van der Jagt, E. W., & Zaritsky, A. L. (2010). Part 14: Pediatric advanced life support: 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation, 122(suppl 3), S876-S908. doi:10.1161/CIRCULATIONAHA.110.971101
Langhan, M. L., Ching, K., Northrup, V., Alletag, M., Kadia, P., Santucci, K., & Chen, L. (2011). A randomized controlled trial of capnography in the correction of simulated endotracheal tube dislodgement. Academic Emergency Medicine, 18(6), 590-596. doi:10.1111/j.1553-2712.2011.01090.x
Lashkeri, T., Howell, J. M., & Place, R. (2012). Capnometry as a predictor of admission in bronchiolitis. Pediatric Emergency Care, 28(9), 895-897. doi:10.1097/PEC.0b013e318267c5b6
Moses, J. M., Alexander, J. L., & Agus, M. S. D. (2009). The correlation and level of agreement between end-tidal and blood gas pCO2 in children with respiratory distress: A retrospective analysis. BMC Pediatrics, 9(20). doi:10.1186/1471-2431-9-20
Nagler, J., Wright, R. O., & Krauss, B. (2006). End-tidal carbon dioxide as a measure of acidosis among children with gastroenteritis. Pediatrics, 118(1), 260–267. doi:10.1542/peds.2005-2723
Neema, P. K., Jayant, A., Sethuraman, M., & Rathod, R. C. (2008). Mainstream time-capnography: an aid to select an appropriate uncuffed endotracheal tube in small children. Journal of Clinical Monitoring and Computing, 22(6), 445-447. doi:10.1007/s10877-008-9155-7
Pokorna, M., Necas, E., Kratochvil, J., Skripsky, R., Andrlik, M., & Franek, O. (2010). A sudden increase in partial pressure end-tidal carbon dioxide (P(ET)CO2) at the moment of return of spontaneous circulation. Journal of Emergency Medicine, 38(5), 614-621. doi:10.1016/j.jemermed.2009.04.064
Ristagno, G., Tang, W., Chang, Y. T., Jorgenson, D. B., Russell, J. K., Huang, L., Wang, T., Sun, S., & Weil, M. H. (2007). The quality of chest compressions during cardiopulmonary resuscitation overrides importance of timing of defibrillation. Chest, 132(1), 70–75. doi:10.1378/chest.06-3065
Sullivan, K. J., Kissoon, N., & Goodwin, S. R. (2005). End-tidal carbon dioxide monitoring in pediatric emergencies. Pediatric Emergency Care, 21(5), 327-332.Kenny Navarro is an Assistant Professor in the Department of Emergency Medicine at the University of Texas Southwestern Medical School at Dallas. He also serves as the AHA Training Center Coordinator for Tarrant County College. Mr. Navarro serves as an Emergency Cardiovascular Care Content Consultant for the American Heart Association, served on two education subcommittees for NIH-funded research projects, as the Coordinator for the National EMS Education Standards Project, and as an expert writer for the National EMS Education Standards Implementation Team. Send correspondence concerning any articles in this section to Kenneth W. Navarro, The University of Texas Southwestern Medical School at Dallas, 5323 Harry Hines Blvd MC 8890, Dallas, Texas 75390-8890, or e-mail email@example.com.
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