Expired Air Resuscitation
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Mouth-to-mouth resuscitation, a form of
artificial ventilation Artificial ventilation or respiration is when a machine assists in a metabolic process to exchange gases in the body by pulmonary ventilation, external respiration, and internal respiration. A machine called a ventilator provides the person air ...
, is the act of assisting or stimulating
respiration Respiration may refer to: Biology * Cellular respiration, the process in which nutrients are converted into useful energy in a cell ** Anaerobic respiration, cellular respiration without oxygen ** Maintenance respiration, the amount of cellul ...
in which a rescuer presses their mouth against that of the victim and blows air into the person's lungs. Artificial respiration takes many forms, but generally entails providing air for a person who is not
breath Breathing (spiration or ventilation) is the neuroscience of rhythm, rhythmical process of moving air into (inhalation) and out of (exhalation) the lungs to facilitate gas exchange with the Milieu intérieur, internal environment, mostly to flu ...
ing or is not making sufficient respiratory effort on their own. It is used on a patient with a beating heart or as part of
cardiopulmonary resuscitation Cardiopulmonary resuscitation (CPR) is an emergency procedure used during Cardiac arrest, cardiac or Respiratory arrest, respiratory arrest that involves chest compressions, often combined with artificial ventilation, to preserve brain function ...
(CPR) to achieve the internal respiration. Pulmonary ventilation (and hence external respiration) is achieved through manual insufflation of the lungs either by the rescuer blowing into the patient's lungs, or by using a mechanical device to do so. This method of insufflation has been proved more effective than methods which involve mechanical manipulation of the patient's chest or arms, such as the Silvester method. It is also known as expired air resuscitation (EAR), expired air ventilation (EAV), rescue breathing, or colloquially the kiss of life. It was introduced as a life-saving measure in 1950. Mouth-to-mouth resuscitation is a part of most protocols for performing cardiopulmonary resuscitation (CPR) making it an essential skill for
first aid First aid is the first and immediate assistance given to any person with a medical emergency, with care provided to preserve life, prevent the condition from worsening, or to promote recovery until medical services arrive. First aid is gener ...
. In some situations, mouth-to-mouth resuscitation is also performed separately, for instance in near-
drowning Drowning is a type of Asphyxia, suffocation induced by the submersion of the mouth and nose in a liquid. Submersion injury refers to both drowning and near-miss incidents. Most instances of fatal drowning occur alone or in situations where othe ...
and
opiate An opiate is an alkaloid substance derived from opium (or poppy straw). It differs from the similar term ''opioid'' in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain ( ...
overdoses. The performance of mouth-to-mouth resuscitation on its own is now limited in most protocols to
health professional A health professional, healthcare professional (HCP), or healthcare worker (sometimes abbreviated as HCW) is a provider of health care treatment and advice based on formal training and experience. The field includes those who work as a Nursing, nur ...
s, whereas lay first-aiders are advised to undertake full CPR in any case where the patient is not breathing sufficiently.


History

In 1773, English physician William Hawes (1736–1808) began publicising the power of artificial respiration to resuscitate people who superficially appeared to have drowned. For a year he paid a reward out of his own pocket to any one bringing him a body rescued from the water within a reasonable time of immersion. Thomas Cogan, another English physician, who had become interested in the same subject during a stay at Amsterdam, where in 1767 a society for preservation of life from accidents in water was instituted, joined Hawes in his crusade. In the summer of 1774 Hawes and Cogan each brought fifteen friends to a meeting at the Chapter Coffee-house,
St Paul's St Paul's Cathedral, formally the Cathedral Church of St Paul the Apostle, is an Anglican cathedral in London, England, the seat of the Bishop of London. The cathedral serves as the mother church of the Diocese of London in the Church of Engl ...
Churchyard, where they founded the
Royal Humane Society The Royal Humane Society is a British charity which promotes lifesaving intervention. It was founded in 1774 as the ''Society for the Recovery of Persons Apparently Drowned'', for the purpose of rendering first aid in cases of near drowning. Hi ...
as a campaigning group for first aid and resuscitation. Gradually, branches of the Royal Humane Society were set up in other parts of the country, mainly in ports and coastal towns where the risk of drowning was high and by the end of the 19th century the society had upwards of 280 depots throughout the UK, supplied with life-saving apparatus. The earliest of these depots was the Receiving House in Hyde Park, on the north bank of the Serpentine, which was built in 1794 on a site granted by
George III George III (George William Frederick; 4 June 173829 January 1820) was King of Great Britain and King of Ireland, Ireland from 25 October 1760 until his death in 1820. The Acts of Union 1800 unified Kingdom of Great Britain, Great Britain and ...
. Hyde Park was chosen because tens of thousands of people swam in the Serpentine in the summer and ice-skated in the winter. Boats and boatmen were kept to render aid to bathers, and in the winter ice-men were sent round to the different skating grounds in and around London. The society distributed money-rewards, medals, clasps and testimonials, to those who saved or attempted to save drowning people. It further recognized "all cases of exceptional bravery in rescuing or attempting to rescue persons from
asphyxia Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects all the tissues and organs, some more rapidly than others. There are m ...
in mines, wells, blasting furnaces, or in sewers where foul gas may endanger life."


Insufflations

Insufflation, also known as 'rescue breaths' or 'ventilations', is the act of mechanically forcing air into a patient's respiratory system. This can be achieved via a number of methods, which will depend on the situation and equipment available. All methods require good
airway management Airway management includes a set of maneuvers and medical procedures performed to prevent and relieve an airway obstruction. This ensures an open pathway for gas exchange between a patient's lungs and the atmosphere. This is accomplished by either ...
to perform, which ensures that the method is effective. These methods include: * Mouth-to-mouth - This involves the rescuer making a seal between his or her mouth and the patient's mouth and 'blowing', to pass air into the patient's body * Mouth-to-nose - In some instances, the rescuer may need or wish to form a seal with the patient's nose. Typical reasons for this include
maxillofacial Oral and maxillofacial surgery (OMFS) is a surgical specialty focusing on reconstructive surgery of the face, facial trauma surgery, the mouth, head and neck, and jaws, as well as facial plastic surgery including cleft lip and cleft palate s ...
injuries, performing the procedure in water or the remains of vomit in the mouth * Mouth-to-face - Used on both animal muzzles and infants under 2, as this forms the most effective seal on both the mouth and nostrils * Mouth-to-mask – Most organisations recommend the use of some sort of barrier between rescuer and patient to reduce cross infection risk. One popular type is the 'pocket mask'. This may be able to provide higher tidal volumes than a Bag Valve Mask.


Adjuncts to insufflation

Most training organisations recommend that in any of the methods involving mouth-to-patient, that a protective barrier is used, to minimise the possibility of cross infection (in either direction). Barriers available include rigid pocket masks and face shields foldable to keyring-size. These barriers are an example of
personal protective equipment Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, elect ...
to guard the rescuer's face against splashing, spraying or splattering of blood or other potentially infectious materials. These barriers should provide a one-way filter valve which lets the air from the rescuer deliver to the patient while any substances from the patient (e.g. vomit, blood) cannot reach the rescuer. Some additionally feature a filter to reduce the chances of rescuer-to-patient disease transmission. Many adjuncts are single use, though if they are multi use, after use of the adjunct, the mask must be cleaned and
autoclave An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform steriliza ...
d and the filter replaced. It is very important for the mask to be replaced or cleaned because it can act as a transporter of various diseases. The CPR mask is the preferred method of ventilating a patient when only one rescuer is available. Many feature inlets to support supplemental
oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
, which increases the oxygen being delivered from the approximate 17% available in the expired air of the rescuer to around 40-50%.


Efficiency of mouth-to-patient insufflation

Normal atmospheric air contains approximately 21% oxygen when inhaled. After
gaseous exchange Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...
has taken place in the lungs, with waste products (notably
carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
) moved from the bloodstream to the lungs, the air being exhaled by humans normally contains around 17% oxygen. This means that the human body utilises only around 19% of the oxygen inhaled, leaving over 80% of the oxygen available in the exhalatory breath. This means that there is more than enough residual oxygen to be used in the lungs of the patient, which then enters the blood.


Oxygen

The efficiency of artificial respiration can be greatly increased by the simultaneous use of oxygen therapy. The amount of oxygen available to the patient in mouth-to-mouth is around 16%. If this is done through a pocket mask with an oxygen flow, this increases to 40% oxygen. If either a
bag valve mask A bag valve mask (BVM), sometimes known by the proprietary name Ambu bag or generically as a manual resuscitator or "self-inflating bag", is a hand-held device commonly used to provide Modes of mechanical ventilation, positive pressure ventilation ...
or a mechanical ventilator is used with an oxygen supply, this rises to 99% oxygen. The greater the oxygen concentration, the more efficient the gaseous exchange will be in the lungs.


See also

*
Mechanical ventilation Mechanical ventilation or assisted ventilation is the Medicine, medical term for using a ventilator, ventilator machine to fully or partially provide artificial ventilation. Mechanical ventilation helps move air into and out of the lungs, wit ...
- using mechanical devices to assist or replace spontaneous breathing *
Medical emergency A medical emergency is an acute injury or illness that poses an immediate risk to a person's life or long-term health, sometimes referred to as a situation risking "life or limb". These emergencies may require assistance from another, qualified ...


References


External links


Expired Air Resuscitation

Basic first aid advice from the Australian New South Wales ambulance service

Two page pamphlet detailing EAR

UK resuscitation council website – contains information on the latest approved guidelines
{{Emergency medicine First aid Respiration Emergency medical procedures