| Breathing patterns during cardiac arrest. | |
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MedLine Citation:
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PMID: 20489033 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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The absence of respiratory movements is a major criterion recommended for use by bystanders for recognizing an out-of-hospital cardiac arrest (CA), as the persistence of eupneic breathing is considered to be incompatible with CA. The basis for CA-related apnea is, however, uncertain, since brain stem Po(2) is not expected to drop immediately to the critical level where anoxic apnea occurs. It is therefore essential on both clinical and physiological grounds to determine whether and when breathing stops after the onset of CA. In eight patients, we measured the ventilatory response at the onset of ventricular fibrillation (VF) for 12-15 s during the placement of an implantable cardioverter-defibrillator device. We found that regular eupneic breathing was maintained unchanged despite the cessation of systemic and pulmonary blood flow generated by the heart. We extended these findings in adult sheep and found that, as in humans, the normal ventilatory pattern persists unchanged for the first 15 s despite the drop in blood pressure, followed by a progressive increase in minute ventilation, which was sustained for up to 164 s. The ensuing apnea was disrupted by typical gasps occurring at a very slow frequency. These observations suggest a complete "decoupling" between the return of CO(2) to the pulmonary circulation and continued effective respiratory activity, contrary to what we predicted. This delayed cessation of eupneic breathing during the absence of cardiac pump function is likely related to the time needed for brain stem anoxia to develop. These findings challenge the notions that 1) ventilation stops as pulmonary blood flow/cardiac output ceases and 2) the presence of eupneic breathing is a reliable sign of effective cardiac pumping activity. |
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Authors:
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Philippe Haouzi; Nasrollah Ahmadpour; Harold J Bell; Stephen Artman; Javier Banchs; Soraya Samii; Mario Gonzalez; Kevin Gleeson |
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Publication Detail:
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Type: Journal Article Date: 2010-05-20 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 109 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2010 Aug |
Date Detail:
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Created Date: 2010-08-10 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 405-11 Citation Subset: IM |
Affiliation:
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Div. of Pulmonary Medicine, Pennsylvania State Univ., 500 University Dr., PO Box 850, MC H047, Hershey, PA 17033-0850, USA. phaouzi@hmc.psu.edu |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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