Aim of the Study: End tidal carbon dioxide (EtCO 2 ) monitoring is considered to reflect real-time estimation of partial pressure of carbon dioxide in arterial blood (PaCO 2 ) noninvasively. However, knowledge about its relationship with PaCO 2 in critically ill pediatric and neonatal patients is limited. The primary objective was to evaluate predictive capability of end tidal carbon dioxide monitoring and secondary objective was to determine the influence of severity of lung disease on EtCO 2 and PaCO 2 relationship.
Materials and Methods: This was a prospective, nonrandomized, consecutive enrollment study carried out in neonatal and pediatric intensive care units of a tertiary care children hospital. It was conducted in 66 neonates and 35 children receiving mechanical ventilation. Severity of lung disease was estimated by ventilation index and PaO 2 /FiO 2 (P/F) ratio. Simultaneous recording of EtCO 2 and PaCO 2 levels was done and data were analyzed for correlation and agreement.
Results: In neonates, 150 EtCO 2 and PaCO 2 pairs were recorded. The mean weight ± SD of patients was 2.1 ± 0.63 kg. PaCO 2 had a positive correlation with EtCO 2 (r = 0.836, 95% CI = 0.78-0.88). P/F ratio <200 adversely affected relationship. In infants and children, 96 pairs were recorded. Mean age ± SD of patients was 4.20 ± 4.92 years and mean weight ± SD was 13.1 ± 9.49 kg. PaCO 2 had an excellent correlation with EtCO 2 (r = 0.914, 95% CI = 0.87 and 0.94). P/F ratio <200 adversely affected relationship.
Conclusion: EtCO 2 monitoring displayed a good validity to predict PaCO 2. Correlation was affected by low P/F ratio (<200); hence, it is recommended that blood gases be measured in these patients until such time that a good relation can be established between end tidal and arterial CO 2 values.
Strauss RG. Transfusion therapy in neonates. AmJ Dis Child 1991;145:904-11.
Russell GB, Graybeal JM. Reliability of the arterial to end-tidal carbondioxide gradient in mechanically ventilated patients with multisystem trauma. J Trauma 1994;36:317-22.
Kerr ME, Zempsky J, Sereika S, Orndoff P, Rudy EB. Relationship between arterial carbondioxide and end-tidal carbondioxide in mechanically ventilated adults with severe head trauma. Crit Care Med 1996;24:785-90.
Weinger MB, Brimm JE. End-tidal carbondioxide as a measure of arterial carbondioxide during intermittent mandatory ventilation. J Clin Monit 1987;3:73-9.
Hoffman RA, Krieger BP, Kramer MR, Segel S, Bizousky F, Gazeroglu H, et al. End-tidal carbondioxide in critically ill patients during changes in mechanical ventilation. Am Rev Respir Dis 1989;140:1265-8.
Meredith KS, Monaco FJ. Evaluation of a mainstream capnometer and end-tidal carbondioxide monitoring in mechanically ventilated infants. Pediatr Pulmonol 1990;9:254-9.
Rozycki HJ, Sysyn GD, Marshall MK, Malloy R, Wiswell TE. Mainstream end-tidal carbondioxide monitoring in the neonatal intensive care unit. Pediatrics 1998;101:648-53.
Russell GB, Graybeal JM. End-tidal carbondioxide as an indicator of arterial carbondioxide in neurointensive care patients. J Neurosurg Anaesthesiol 1992;4:245-9.
Morley TF, Giaimo J, Maroszan E, Bermingham J, Gordon R, Griesback R, et al. Use of capnography for assessment of the adequacy of alveolar ventilation during weaning from mechanical ventilation. Am Rev Respir Dis 1993;148:339-44.
McEvedy BA, McLeod ME, Kirpalani H, Volgyesi GA, Lerman J. End-tidalcarbon dioxide measurements in critically ill neonates: A comparison of sidestream and mainstream monitors. Can J Anaesth 1990;37:322-6.
McDonald MJ, Montgomery VL, Cerrito PB, Parrish CJ, Boland KA, Sullivan JE. Comparison of end-tidal CO 2 and PaCO 2 in children receiving mechanical ventilation. Pediatr Crit Care Med 2002;3:244-9.
Hopper AO, Nystrom GA, Deming DD, Brown WR, Peabody JL. Infrared end-tidal CO 2 measurement does not accurately predict arterial CO 2 values or end-tidal to arterial PCO 2 gradients in rabbits with lung injury. Pediatr Pulmonol 1994;17:189-96.
Bhat YR, Abhishek N. Mainstream end-tidal carbondioxide monitoring in ventilated neonates. Singapore Med J 2008;49:199-203.
Trevisanuto D, Giuliotto S, Cavallin F, Doglioni N, Toniazzo S, Zanardo V. End-tidal carbondioxide monitoring in very low birth weight infants: Correlation and agreement with arterial carbon dioxide. Pediatr Pulmonol 2012;47:367-72.
Singh BS, Gilbert U, Singh S, Govindaswami B. Sidestream microstream end-tidal carbondioxide measurements and blood gas correlations in neonatal intensive care unit. Pediatr Pulmonol 2013;48:250-6.