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Commentary

Partial pressure of end-tidal carbon dioxide predicts successful cardiopulmonary resuscitation in the field

Max Harry Weil

Author Affiliations

Weil Institute of Critical Care Medicine, 35100 Bob Hope Drive, Rancho Mirage, CA 92270, USA

Keck School of Medicine of the University of Southern California, 1975 Zonal Avenue, KAM 317, Los Angeles, CA 90087 USA

Critical Care 2008, 12:90  doi:10.1186/cc7090


See related research by Kolar et al., http://ccforum.com/content/12/5/R115


The electronic version of this article is the complete one and can be found online at: http://ccforum.com/content/12/6/190


Published:7 November 2008

© 2008 BioMed Central Ltd

Abstract

Kolar and colleagues contribute an additional and important incentive for rescuers to utilize end-tidal carbon dioxide tensions as a routine monitor to guide management and decision-making during cardiopulmonary resuscitation. They conclude that below-threshold levels of 14 mmHg (1.5 kPa) measured after 20 minutes of cardiopulmonary resuscitation reliably predict that spontaneous circulation cannot be restored.

Commentary

In their report on 737 patients who sustained out-of-hospital cardiac arrest, collected over an interval of 9 years in a well-organized emergency medical system, Kolar and colleagues confirmed that the measurement of end-tidal carbon dioxide tension (PetCO2) is predictive of the outcomes of cardiopulmonary resuscitation [1]. The authors provide impressive data supporting the conclusion that, in their population, failure to increase PetCO2 to levels exceeding 14 mmHg (1.5 kPa) after 20 minutes of attempted resuscitation served as a reliable guide for terminating unsuccessful cardiopulmonary resuscitation. The population studied, however, differed in some respects from the majority of earlier demographic reports that the authors cited with hospital survival <3%. More than 53% survived. The majority of instances of cardiac arrest reported by them was witnessed, and as many as one-third of victims received bystander cardiopulmonary resuscitation – favoring improved outcomes. Fatal outcomes, as anticipated, were associated with a doubling of the response time of professional rescuers, presumably in the absence of bystander utilization of automated external defibrillators, especially since a majority of survivors had shockable ventricular fibrillation or ventricular tachycardia.

As the authors pinpoint, PetCO2 has evolved into a technically facile and singularly useful monitor to guide cardiopulmonary resuscitation. PetCO2 provides an indirect measurement of the cardiac output generated by chest compression and thereby guides the effectiveness of the procedure, including chest compression, to achieve better outcomes. It also allows uninterrupted chest compression because it promptly signals the return of spontaneous circulation [2]. PetCO2 is likely to promptly identify asphyxia, in contrast to primary cardiac causes of arrest as previously reported by one of the present authors [3]. PetCO2 measurement during cardiopulmonary resuscitation may not require routine endotracheal intubation, which usually interrupts chest compression and under crisis conditions has a high failure rate and disproportionate airway injury. The alternatives of a laryngeal mask airway or even a facial mask incorporating a mainstream carbon dioxide sensor may be utilized. Because injection of bolus epinephrine produces a sharp although transient reduction in PetCO2 when injected intravenously [4], clinicians would best be alerted to this potential error.

These considerations notwithstanding, Kolar and colleagues contribute an additional and important incentive for rescuers to utilize PetCO2 as a routine monitor to guide management and decision-making during cardiopulmonary resuscitation.

Abbreviations

PetCO2: end-tidal carbon dioxide tension.

Competing interests

The author declares that he has no competing interests.

References

  1. Kolar M, Krizmaric M, Klemen P, Grmec S: Partial pressure of end-tidal carbon dioxide successful predicts cardiopulmonary resuscitation in the field: a prospective observational study.

    Crit Care 2008, 12:R115. PubMed Abstract | BioMed Central Full Text | PubMed Central Full Text OpenURL

  2. Falk J, Rackow EC, Weil MH: End-tidal carbondioxide concentration during cardiopulmonary resuscitation.

    N Engl J Med 1988, 318:607-611. PubMed Abstract OpenURL

  3. Grmec S, Lah K, Tusek-Bunc K: Difference in end-tidal CO2 between asphyxia cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest in the prehospital setting.

    Crit Care 2003, 7:R139-R44. PubMed Abstract | BioMed Central Full Text | PubMed Central Full Text OpenURL

  4. Cantineau JP, Merckx P, Lambert Y, Sorkine M, Bertrand C, Duvaldestin P: Effect of epinephrine on end-tidal carbon dioxide during prehospital cardiopulmonary resuscitation.

    Am J Emerg Med 1994, 12:267-270. PubMed Abstract | Publisher Full Text OpenURL