Elsevier

Resuscitation

Volume 49, Issue 2, May 2001, Pages 123-134
Resuscitation

The respiratory system during resuscitation: a review of the history, risk of infection during assisted ventilation, respiratory mechanics, and ventilation strategies for patients with an unprotected airway

https://doi.org/10.1016/S0300-9572(00)00349-XGet rights and content

Abstract

The fear of acquiring infectious diseases has resulted in reluctance among healthcare professionals and the lay public to perform mouth-to-mouth ventilation. However, the benefit of basic life support for a patient in cardiopulmonary or respiratory arrest greatly outweighs the risk for secondary infection in the rescuer or the patient. The distribution of ventilation volume between lungs and stomach in the unprotected airway depends on patient variables such as lower oesophageal sphincter pressure, airway resistance and respiratory system compliance, and the technique applied while performing basic or advanced airway support, such as head position, inflation flow rate and time, which determine upper airway pressure. The combination of these variables determines gas distribution between the lungs and the oesophagus and subsequently, the stomach. During bag–valve–mask ventilation of patients in respiratory or cardiac arrest with oxygen supplementation (≥40% oxygen), a tidal volume of 6–7 ml kg−1 (∼500 ml) given over 1–2 s until the chest rises is recommended. For bag–valve–mask ventilation with room-air, a tidal volume of 10 ml kg−1 (700–1000 ml) in an adult given over 2 s until the chest rises clearly is recommended. During mouth-to-mouth ventilation, a breath over 2 s sufficient to make the chest rise clearly (a tidal volume of ∼10 ml kg−1 ∼700–1000 ml in an adult) is recommended.

Resumen

O medo de adquirir doenças infecciosas leva a alguma relutância na realização de ventilação boca-a-boca quer entre profissinais da saúde, quer no público em geral. Contudo o benefı́cio do suporte básico de vida numa vı́tima em paragem respiratória ou cardiopulmonar ultrapassa largamente o risco de infecção secundária para o reanimador e para o doente. A distribuição do volume ventilatório entre os pulmões e o estômago nos doentes sem via aérea protegida depende de variáveis inerentes ao doente como: a pressão do esfı́ncter esofágico inferior, resistência da via aérea e compliance do sistema respiratório. Depende também de variáveis relacionadas com a técnica aplicada quando se realizam manobras de suporte básico ou avançado de vida, tais como: posição da cabeça, o fluxo inspiratório e o tempo de insuflação, que determinam a pressão na via aérea superior. A conjugação destas variáveis determina a distribuição de “gás” entre os pulmões e o esófago e subsequentemente o estômago. Durante a ventilação de doentes em paragem respiratória ou cardı́aca com insuflador manual e máscara e suplemento de oxigénio (oxigénio ≥40%) recomenda-se um volume corrente de 6–7 ml/kg (∼500 ml) administrado em 1–2 s até o tórax expandir. Na ventilação, no adulto, com insuflador e máscara com ar ambiente recomenda-se um volume corrente de 10 ml/kg (700–1000 ml) administrado em 2 segundos até o tórax expandir claramente. Durante a ventilação boca-a-boca recomenda-se um volume corrente de ∼10 ml/kg administrado em 2 segundos, verificando se o tórax expande claramente.

Section snippets

Assisted ventilation: the history

Attempts to provide ventilation for victims of respiratory and cardiac arrest have been described throughout history. Early descriptions are found in the Bible [1], [2], Egyptian mythology [3], and in anecdotal reports in the medical literature of resuscitation of victims of accidents and illness. In A.D. 177, the Greek scientist Galen performed a thoracotomy in swine and ventilated the animal with a self-inflatable bag [4]; in the 16th century, Paracelsus performed a tracheotomy in a pig and

Mouth-to-mouth ventilation and the fear of infectious diseases

In the last decade, the acquired immune deficiency syndrome caused by the human immunodeficiency virus (HIV) became a world-wide health risk, and resulted in a fear of infection during mouth-to-mouth ventilation. For example, 97% of CPR instructors stated in a survey that they would perform mouth-to-mouth ventilation on a 4-year-old drowned child, 54% on a college student, 35% on a haemophiliac, 18% on a stranger in a bus in San Francisco, and only 10% on a person with an overdose of heroin [32]

Respiratory mechanics of the unprotected airway affect stomach inflation

While the discussion about whether healthcare professionals or lay bystanders should or should not perform mouth-to-mouth ventilation has an emotional component, the question of whether satisfactory lung ventilation in an unintubated cardiac arrest patient can be achieved, is clearly a scientific issue. If ventilation strategies can be identified that could be beneficial for the patient, and not harmful for the rescuer, CPR outcome may be improved.

The distribution of ventilation volume between

Bag–valve–mask ventilation, and mouth-to-mouth ventilation in an unprotected airway

In an in vitro model of an unprotected airway, significantly less stomach inflation was found when applying a tidal volume of ∼500 ml with a mechanical ventilator compared with a tidal volume of ∼1000 ml [66]. Controlling inflation time, flow rate, and the flow wave form with a mechanical ventilator may be the best solution to control and to limit peak inflation pressure for a given tidal volume, but these variables may not be controlled easily during manual ventilation. A simple, portable

Cricoid pressure/Sellick manoeuvre to prevent stomach inflation

An option to prevent stomach inflation during ventilation with an unprotected airway is to apply cricoid pressure; this is a simple, effective manoeuvre to prevent stomach inflation [89] that was first described 200 years ago [90]. In a model of human cadavers, an intraoesophageal pressure of 75 cm H2O was required to overcome cricoid pressure; indicating that the Sellick manoeuvre may be able to prevent gastric distension even when ventilating with a high peak inflation pressure [91] (Fig. 4).

Gasping and ventilation induced by chest compressions provide some, but not sufficient gas exchange

In animal models with no muscle paralysis, ventilation induced by gasping and chest compressions was sufficient for adequate carbon dioxide elimination and oxygenation [100], [101]. When gasping during ventricular fibrillation in swine was prevented with a neuromuscular blocking agent, ventilation induced by chest compressions failed to maintain adequate carbon dioxide elimination and oxygenation; and ventilated pigs were more likely to survive than pigs that received chest compressions only

Summary

When an oxygen source is available, it is recommended that tidal volumes are reduced from ∼1000 to ∼500 ml (FiO2≥40%) when ventilating a patient with an unprotected airway. A tidal volume of 500 ml during bag–valve–mask ventilation may be a better trade-off in the basic life support phase of CPR; although mouth-to-mouth ventilation tidal volumes should remain 700–1000 ml. This strategy would provide reasonable ventilation and oxygenation while avoiding massive gastric inflation that may result

Acknowledgements

Supported, in part, by grant 91GIA/721 from the American Heart Association, Florida Affiliate; the Laerdal Foundation for Acute Medicine, Stavanger, Norway; the Austrian Science Foundation grant P14169-MED, Vienna, Austria; the Founders grant of the Society of Critical Care Medicine, Anaheim, California, United States; and the Department of Anesthesiology and Critical Care Medicine, Leopold-Franzens-University, Innsbruck, Austria.

References (119)

  • P.G. Rabey et al.

    Effect of the laryngeal mask airway on lower oesophageal sphincter pressure in patients during general anaesthesia

    Br. J. Anaesth.

    (1992)
  • F.P. Bowman et al.

    The lower esophageal sphincter pressure during prolonged cardiac arrest and resuscitation

    Ann. Emerg. Med.

    (1995)
  • J.P. Krischer et al.

    Complications of cardiac resuscitation

    Chest

    (1987)
  • V. Wenzel et al.

    Respiratory system compliance decreases after cardiopulmonary resuscitation and stomach inflation: impact of large and small tidal volumes on calculated peak airway pressure

    Resuscitation

    (1998)
  • D.M. Raidoo et al.

    Critical volume for pulmonary acid aspiration; reappraisal in a primate model

    Br. J. Anaesth.

    (1990)
  • H. Ruben

    Immediate treatment of respiratory failure

    Br. J. Anesth.

    (1964)
  • A. Ruben et al.

    Rescue breathing

    Lancet

    (1959)
  • P. Baskett et al.

    Tidal volumes which are perceived to be adequate for resuscitation

    Resuscitation

    (1996)
  • V. Wenzel et al.

    Effects of smaller tidal volumes during basic life support ventilation in patients with respiratory arrest: good ventilation, less risk?

    Resuscitation

    (1999)
  • V. Wenzel et al.

    The composition of gas given by mouth-to-mouth-ventilation during CPR

    Chest

    (1994)
  • V. Dörges et al.

    Smaller tidal volumes with room-air are not sufficient to ensure adequate oxygenation during basic life support

    Resuscitation

    (2000)
  • V. Dörges et al.

    Optimisation of tidal volumes given with self-inflatable bags without additional oxygen during simulated basic life support

    Resuscitation

    (2000)
  • B.A. Sellick

    Cricoid pressure to control regurgitation of stomach contents during induction of anesthesia

    Lancet

    (1961)
  • E.G. Lawes et al.

    Inflation pressure, gastric insufflation and rapid sequence induction

    Br. J. Anaesth.

    (1987)
  • The Bible, II. Kings,...
  • J.A. Paraskos

    Biblical accounts of resuscitation

    J. Hist. Med. All. Sci.

    (1992)
  • A.B. Baker

    Artificial respiration, the history of an idea

    Med. History

    (1971)
  • S. Thangam et al.

    Cardiopulmonary resuscitation: A historical review

    Acute Care

    (1986)
  • M.S. Eisenberg

    The quest to reverse sudden death. A history of cardiopulmonary resuscitation

  • R.V. Lee

    Cardiopulmonary resuscitation in the eighteenth century. A historical perspective on present practice

    J. Hist. Med.

    (1972)
  • S.M. Brooks
  • F. Trendelenburg

    Beiträge zu den Operationen an den Luftwegen: Tamponade der Trachea

    Arch. Klin. Chir.

    (1871)
  • R. Boehm

    Wiederbelebung nach Vergiftungen und Asphyxie

    Arch. Exp. Patho. Pharma.

    (1878)
  • Herholdt J.D., Rasn C.G. An attempt at an historical survey on life saving measures for drowning persons and...
  • G.W. Crile et al.

    An experimental research into the resuscitation of dogs killed by anesthetics and asphyxia

    J. Exp. Med.

    (1906)
  • J.O. Elam et al.

    Artificial respiration by mouth-to-mask method: a study of the respiratory gas exchange of paralyzed patients ventilated by operator's expired air

    N. Engl. J. Med.

    (1954)
  • P. Safar

    History of cardiopulmonary-cerebral resuscitation

  • W.B. Kouwenhoven et al.

    Closed-chest cardiac massage

    J. Am. Med. Assoc.

    (1960)
  • B.A. Johnson et al.

    Redefining ischemia due to circulatory failure as dual defects of oxygen deficits and of carbon dioxide excesses

    Crit. Care Med.

    (1991)
  • A.S. Gordon et al.

    Artificial respiration: a new method and a comparative study of different methods in adults

    J. Am. Med. Assoc.

    (1950)
  • P. Safar

    Failure of manual respiration

    J. Appl. Physiol.

    (1959)
  • P. Safar et al.

    Ventilation and cirulation with closed-chest cardiac massage in man

    J. Am. Med. Assoc.

    (1961)
  • P. Safar et al.

    Upper airway obstruction in the unconscious patient

    J. Appl. Physiol.

    (1959)
  • P. Safar et al.

    A comparison of the mouth-to-mouth and mouth-to-airway methods of artificial respiration with the chest-pressure arm-lift methods

    New Engl. J. Med.

    (1958)
  • Resuscitation: controversial aspects. An International Symposium. Held at the first European Congress of...
  • L.A. Cobb et al.

    Report of the American Heart Association task force on the future of cardiopulmonary resuscitation

    Circulation

    (1992)
  • L.B. Becker et al.

    A reappraisal of mouth-to-mouth ventilation during bystander-initiated cardiopulmonary resuscitation. A statement for healthcare professionals from the Ventilation Working Group of the Basic Life Support and Pediatric Life Support Subcommittees, American Heart Association

    Circulation

    (1997)
  • C.J. Locke et al.

    Bystander cardiopulmonary resuscitation. Concerns about mouth-to-mouth contact

    Arch. Intern. Med.

    (1995)
  • C.J. Locke et al.

    Bystander cardiopulmonary resuscitation. Concerns about mouth-to-mouth contact

    Arch. Inter. Med.

    (1995)
  • G.H. Friedland et al.

    Lack of transmission of HTLV-III/LAV infection to household contacts of patients with AIDS or AIDS-related complex with oral candiasis

    New Engl. J. Med.

    (1986)
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