Fast or Slow Rescue Ventilations: A Predictive Model of Gastric Inflation.
BACKGROUND: Rescue ventilations are given during respiratory and cardiac arrest. Tidal volume must assure oxygen delivery; however, excessive pressure applied to an unprotected airway can cause gastric inflation, regurgitation, and pulmonary aspiration. The optimal technique provides mouth pressure...
| Publicado en: | Respiratory Care Vol. 63; no. 5; pp. 502 - 510 |
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| Autor principal: | |
| Formato: | research tables/charts Journal Article |
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Mary Ann Liebert, Inc.
May2018
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=129399390&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 129399390 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 00201324 4GG jtl: Respiratory Care issn: 00201324 maglogo: N pubinfo: dt: May2018 vid: 63 iid: 5 pid: 1365 pub: Mary Ann Liebert, Inc. place: New Rochelle, New York artinfo: ui: 129399390 129399390 129399390 10.4187/respcare.05620 129399390 ppf: 502 ppct: 8 formats: fmt: @attributes: type: P tig: atl: Fast or Slow Rescue Ventilations: A Predictive Model of Gastric Inflation. aug: au: Fitz-Clarke, John R. affil: Department of Emergency Medicine, Dalhousie University, Halifax, Nova Scotia, Canada sug: subj: Respiration, Artificial Methods Human Airway Management Aspiration Insufflation Stomach Anatomy and Histology Gases Esophagus Anatomy and Histology Positive Pressure Ventilation Resuscitation Lung Physiology Respiratory Function Tests Tidal Volume Life Support Care Mouth Breathing Models, Biological ab: BACKGROUND: Rescue ventilations are given during respiratory and cardiac arrest. Tidal volume must assure oxygen delivery; however, excessive pressure applied to an unprotected airway can cause gastric inflation, regurgitation, and pulmonary aspiration. The optimal technique provides mouth pressure and breath duration that minimize gastric inflation. It remains unclear if breath delivery should be fast or slow, and how inflation time affects the division of gas flow between the lungs and esophagus. METHODS: A physiological model was used to predict and compare rates of gastric inflation and to determine ideal ventilation duration. Gas flow equations were based on standard pulmonary physiology. Gastric inflation was assumed to occur whenever mouth pressure exceeded lower esophageal sphincter pressure. Mouth pressure profiles that approximated mouth-to-mouth ventilation and bag-valve-mask ventilation were investigated. Target tidal volumes were set to 0.6 and 1.0 L. Compliance and airway resistance were varied. RESULTS: Rapid breaths shorter than 1 s required high mouth pressures, up to 25 cm H2O to achieve the target lung volume, which thus promotes gastric inflation. Slow breaths longer than 1 s permitted lower mouth pressures but increased time over which airway pressure exceeded lower esophageal sphincter pressure. The gastric volume increased with breath durations that exceeded 1 s for both mouth pressure profiles. Breath duration of -1.0 s caused the least gastric inflation in most scenarios. Very low esophageal sphincter pressure favored a shift toward 0.5 s. High resistance and low compliance each increased gastric inflation and altered ideal breath times. CONCLUSIONS: The model illustrated a general theory of optimal rescue ventilation. Breath duration with an unprotected airway should be 1 s to minimize gastric inflation. Short pressure-driven and long duration-driven gastric inflation regimens provide a unifying explanation for results in past studies. pubtype: Academic Journal doctype: research tables/charts Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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