mouth-to-mouth breathing

Image: “Mund-zu-Mund-Beatmung” by Hauptabteilung der Schutzpolizei der DDR. License: CC BY-SA 3.0

General Information about Emergencies

Oxygen supply to the organs is crucial to preserve life, and maintenance of respiration and the circulatory system are vital as their failure can result in rapid mortality. With insufficient oxygen supply, the brain becomes irreversibly damaged after 3–5 minutes. Insufficient oxygen supply for longer time periods damages other organ systems which could ultimately result in death.

Respiratory arrest results in cardiac arrest after 5–10 minutes due to the subsequent hypoxia. In the case of cardiac arrest, the heart does not pump enough blood into the circulation, and the brain is not supplied enough oxygen; the patient becomes unconscious within a brief period of time.

The lack of oxygen supply to the respiratory center located in the brain stem results in a loss of spontaneous respiration after only 1 minute.

Learning the basics of 1st-aid and resuscitation not just theoretically, but also practically, is crucial for prompt use in emergency situations.

Polytrauma as a serious emergency

In addition to sudden cardiac arrest and accidents in the home environment, doctors may come in contact with more severe cases. So-called polytraumas (e.g., from a traffic accident) are particularly challenging for emergency care providers.

Note: Polytraumas are defined as injuries in various parts of the body that occur at the same time, of which one injury or a combination of them is life-threatening.

The principle of the clinical treatment of polytraumas is ‘Treat first what kills first’. This means that injuries that are most fatal to the patient must be treated 1st. Additional injuries are treated provisionally and then definitively once the patient has been successfully stabilized.

Basic Life Support

Only very rarely are the 1st responders to an accident or other medical emergencies medically trained individuals. More often, they are passersby or witnesses, i.e., medical laypersons.

Basic life support (BLS) describes all measures of cardiopulmonary resuscitation (CPR) that can be performed by 1st responders. In broader terms, BLS includes calling for assistance, freeing the airways, cardiac massage, respiration, and currently, the usage of an AED (automated external defibrillator).

Reporting the incident

The incident should immediately be reported if there is an apparent need for assistance. In the best-case scenario, multiple helpers are present at the emergency site, one of whom can begin performing 1st-aid measures while another alerts the emergency rescue services by phone (call 911).

If an individual appears unconscious, the emergency rescue team is alerted immediately after the breath test is conducted and before a cardiac massage begins.

These 5 questions should be remembered for the proper and prompt relay of information:

  • Where (emergency site)?
  • What (happened)?
  • How many injured?
  • Which injuries?
  • Wait for questions from the emergency dispatcher (do not hang up immediately once all information has been provided).

Self-protection and protection of others

One of the most important principles of 1st-aid is self-protection. A rescue worker should never put their own life at risk by putting themselves in dangerous situations. If their own safety is ensured (or if they are not in danger), the injured person must be removed from the dangerous area (protection of others).

The Rautek maneuver is designed for this, and it can be used to pull a patient backward from the danger area (fire, accident site, etc.).

With the Rautek maneuver, the patient is grabbed from behind under the arms, one of the patient’s arms is held against their chest and the forearm is held by the left and right hand of the rescue worker. This allows the responder to pull the injured person with relative stability.

Exam tip: The Rautek maneuver does not only help in emergencies but is also a common topic for examination questions.

Unconscious patient: Breath test

If a presumably unconscious patient is found, they should be spoken to. If they do not respond, their shoulders should be carefully shaken. If they remain unresponsive, their breathing must be checked. The airways can be freed up by overflexing the head or lifting the chin. When performing the breath test, all of the senses (sight, hearing, and feeling) are used.

It is best to keep the head tilted just over the patient’s face, the gaze directed toward their ribcage, ears, and cheeks, near the mouth and nose.

The responder must work with the senses:

  • Sight: Is their chest moving up and down?
  • Hearing: Can respiration be heard from the nose or mouth?
  • Feeling: Heave of the chest, air from breathing.

Assessment of the patient’s respiration should last for a maximum of 10 seconds. Professional assistants can also check the carotid pulse, but this should also not last for more than 10 seconds in order not to lose any valuable time in case of a necessary resuscitation. In doubtful cases, an unnecessary cardiac massage does much less damage than one that is begun too late.

If the patient is breathing regularly, they must be placed in the recovery position and then emergency services should be alerted. If the patient is breathing only sporadically, irregularly, or not breathing at all, CPR and possibly defibrillation with an AED is required. Currently, these devices are installed in many public areas and institutions.

Recovery position

Recovery position

Image: Stable lateral position. By Hauptabteilung der Schutzpolizei der DDR, License: CC BY-SA 3.0

If the patient is breathing but is not responding when spoken to, they must be placed in the recovery position. This way, the patient should be able to breathe.

Overflexion of the head prevents the tongue from sliding into the throat and blocking the airways. The recovery position prevents any potential aspiration of vomit, as the mouth is lying lower than the rest of the body and vomitus or blood can flow out.

If the patient is in the recovery position, respiration and circulation must still be regularly monitored until the emergency rescue services arrive as the patient’s health can deteriorate, and a cardiac arrest is not to be ruled out.

Cardiopulmonary resuscitation

If a person is not responding and if the breath test reveals apnea or gasping, cardiac massage and ventilation must commence immediately. Lack of a pulse is not sufficient criteria for making a decision.

Essentially, measures of resuscitation must be performed for as long as it takes for the patient to show signs of life, qualified medical professionals to arrive, or until the 1st responder is exhausted.

Note: Gasping is also a sign of circulatory arrest! In 40% of cases, it precedes apnea and circulatory arrest.

CPR training

Image: CPR training. By Rama, License: CC BY-SA 2.0 FR

Cardiac massage

To perform cardiac massage, the person must be lying on their back on a solid surface (on the floor if necessary). The balls of the hand are placed over one another in the middle of the sternum, with fingers laced. The pressure must come down vertically from the arms, which should be as outstretched as possible.

Ideally, the 1st-aid provider is kneeling at the patient’s side. According to the guidelines of the ERC (European resuscitation council), the goal is to achieve a compression depth of at least 5 cm (1.9 in) and a pressure frequency of at least 100 per minute.

Tip: You can think of the song ‘Stayin’ Alive’ by the Bee Gees to find the proper rhythm – at 103 beats per minute, this is a good aid.

After each compression, the thorax must be completely relieved, but the balls of your hands must remain at the pressure point. In principle, the cardiac massage begins immediately, before the respiration.

Rescue breathing

A respiration ratio of 30:2 is ideal (30 compressions followed by 2 breaths). The respiration can either occur via mouth-to-mouth or mouth-to-nose.

mouth-to-nose breathing

Image: Mouth-to-nose respiration. By Hauptabteilung der Schutzpolizei der DDR, License: CC BY-SA 3.0

Both types require an overflexion of the head, to keep the airways free (1 hand is kept on the patient’s hairline, the fingers of the other hand hold up the chin). With mouth-to-mouth resuscitation, the patient’s nose must also be held shut so that the air provided does not immediately exit.

mouth-to-mouth breathing

Image: Mouth-to-mouth resuscitation. By Hauptabteilung der Schutzpolizei der DDR, License: CC BY-SA 3.0

The person providing the respiration generally performs a full inhalation and then blows the exhaled air continuously into the patient. A heave of the thorax shows whether the respiration was successful (thoracic excursion). After inhaling, the helper then turns their head and observes the patient’s thorax – this should lower again during the next passive exhalation.

Both forms of respiration should not take longer than 5 seconds, as the cardiac massage must then be continued.

Laypersons may also perform ‘chest-compression-only CPR’, in which only a cardiac massage is performed with no respiration. This also applies in the event that respiration is not possible for other reasons, such as due to facial injuries or for hygiene or personal reasons.

Studies have shown that the inhibition threshold of beginning CPR is lower among laypersons if they only have to perform cardiac massage. The cardiac massage should be not interrupted. However, if an interruption is inevitable, it should be as short as possible.

Automated external defibrillator

In accordance with the ERC resuscitation guidelines, BLS also entails the use of an AED. If such a device is available in an emergency, it should be used. AEDs can be found in many public spaces, such as train stations and airports. However, immediate cardiac massage is still the most important measure. Ideally, a third person will be asked to bring and prepare the AED.

position of pads

Image: Position of the electrodes. By PhilippN, License: CC BY-SA 3.0

An AED has 2 large adhesive electrodes (pads) that are placed on the patient following the instructions provided with the AED. The device conducts an automatic ECG diagnosis and declares whether defibrillation is required via voice command.

The cardiac massage is briefly interrupted and everybody present must keep a safe distance away from the patient so as not to be put in danger by the electrical shock, as this can trigger ventricular fibrillation in healthy individuals. Moreover, they must not be standing in a puddle near the patient! Afterward, cardiac massage must be continued immediately.

Generally, the device automatically will give directions after 2 minutes for a new diagnosis and possibly defibrillation.

Advanced Life Support

Measures taken by professional medical assistants are called Advanced life support (ALS).

While the diagnosis and CPR are conducted just as in BLS, ALS also includes electrical defibrillation, ECG diagnostics, securing the airways (e.g., via intubation), and administration of medication.

One of the 1st measures taken by the rescue team at the emergency site – after securing the area – is assessing the patient’s state of consciousness.

Glasgow coma scale

The Glasgow coma scale (Teasdale and Jenett, 1974) is used for an objective assessment of the level of consciousness and brain functions after a traumatic brain injury. The parameters of the scale should be used by an emergency medic in every emergency and be compiled when the emergency medic arrives at the emergency site to better document and assess the procedure.

The patient is scored in the areas of ‘best eye response’, ‘best verbal response’, and ‘best motor response’. A minimum of 3 points and a maximum of 15 can be achieved. Severe traumatic brain injury is assumed for a score of < 8 points. This entails the need for endotracheal intubation to secure the airway.

Best eye response
4 = spontaneous; 3 = to voice command; 2 = to pain; 1 = none
Best verbal response 5 = orientated; 4 = confused but coherent; 3 = incoherent words; 2 = incomprehensible sounds; 1 = none
Best motor response
6 = obeys commands; 5 = localizes pain; 4 = withdrawal from pain; 3 = abnormal flexion (decorticate posture); 2 = extensor response (decerebrate posture); 1 = none

Primary survey: The ABCDE approach

Each emergency requires an individual approach from the attending team and physician, but in order to ensure nothing important is overlooked in an emergency or when time is of the essence, a procedure following the ABCDE approach has proven effective. It ensures that the 3 most important vital parameters – consciousness, respiration, and circulation – can be systematically evaluated and treated.

A: Airway Check the airways
B: Breathing Check respiration
C: Circulation Check circulation
D: Disability Check consciousness, orientating neurological examination
E: Exposure Examine the undressed patient for injuries, bleeding, etc.

Trauma assessment

Trauma assessment is part of the systematic evaluation of the awake emergency patient (following the ABCDE approach, it corresponds to E – exposure) with the goal of systematically documenting injuries and not overlooking any injuries that require treatment. If the patient is unconscious, then a rough assessment of dislocations, bleeding, and injuries are performed.

Trauma assessment consists of the following steps:

  • Brief anamnesis
  • Head assessment
  • Assessment of the spine
  • Assessment of the thorax and abdomen (palpation, percussion, auscultation)
  • Assessment of pelvic stability
  • Assessment of pain in the spine and neurological deficits
  • Assessment of the extremities for dislocations, injuries, motor function, and sensitivity
  • Monitoring circulation (measuring blood sugar, blood pressure, heart rate, ECG lead, pulse oximetry, monitoring respiration)

Causes of circulatory arrest

Signs of circulatory arrest are lack of pulse and apnea.

The reasons for circulatory arrest may vary: cardiac (e.g., myocardial infarction, coronary heart disease, myocarditis, cardiac arrhythmias), respiratory (pulmonary edema, apnea, pneumothorax), cerebral (traumatic brain injury, stroke).

Hypoxia, hyperthermia, or metabolic lapses can, in an extreme case, trigger circulatory arrest—this can only be treated by resuscitation within a brief window of time of about 3–5 minutes.

Should cardiac arrhythmias lead to a lack of blood circulation in the body, the heart still exhibits electrical activity and may have to be defibrillated.


The voltage applied during defibrillation charges all of the heart muscles at once. After such synchronization, the likelihood that the conduction and excitation in the heart will continue to function in a normal rhythm increases.

The emergency defibrillation process conducted by medically trained personnel is similar to that by the AED. The cardiac massage is briefly interrupted to fasten the ECG electrodes, and an emergency ECG diagnosis is performed. While the device charges, the cardiac massage is continued. Once the device is charged, it’s ‘hands off’: everybody must move a safe distance away from the patient.

The electrodes are placed in a sternal-apical position, i.e., 1 in the right-parasternal area below the clavicle and the other in a left-lateral area near the cardiac apex. The patient is shocked and the cardiac massage continues immediately thereafter.

After a resuscitation cycle (by definition: 2 minutes = 5 x 30 cardiac massages + 2 respirations), another ECG diagnosis should be performed and another defibrillation should be done if necessary.

Steps of Reanimation

Image: Algorithm for cardiopulmonary resuscitation (CPR). By Andante (edited), License: CC BY-SA 3.0

There are generally 2 forms of electrical defibrillation: monophasic and biphasic defibrillation. Today, biphasic defibrillation (alternating current) is recommended since a lower number of joules reduces the risk of long-term damage to the heart muscle cells while still achieving the same effect.

 Exam tip: For the exam, you should know that monophasic defibrillation works with 360 joules. Biphasic defibrillation uses 150 – 200 joules (150 – 360 for additional shocks).

Defibrillate rhythms

The prerequisite for defibrillation is the presence of a defibrillate heart rhythm is pulseless ventricular tachycardia or ventricular fibrillation. Ventricular fibrillation is the most common cause of cardiac arrest. On ECG, this is seen as arrhythmic flutter waves — the cardiac excitation is so uncoordinated that the heart muscles can no longer contract, and no ejection fraction is present.

Pulseless ventricular tachycardia represents a rapid and regular ventricular contraction. At the same time, this keeps the heart’s ejection fraction too low — often the pulse cannot be felt, or if there is, only the carotid pulse is noted.

In the case of asystolia (no electrical activity on the ECG) and PEA (pulseless electrical activity), defibrillation is not performed. The treatment of choice for both is the immediate intravenous administration of 1 mg of adrenaline (for adults), which is injected after every second resuscitation cycle. If in this manner, the heart’s activity is increased to the extent that ventricular fibrillation waves are seen, defibrillation can be performed.

Digression: Resuscitating Children

reanimation of child

Image: Reanimation of a child. By Egil, License: Public domain

There are special ERC guidelines for resuscitating newborns and children. One crucial difference between adults is that the child’s respiration, not their heart, must often be supported.

In newborns, the restoration of respiration is 1st attempted 5 times. There should be a repeat attempt 5 more times if the first is unsuccessful, and only then is thoracic compression performed.

One 1st-aid provider should use the 2-finger technique for newborns, while multiple 1st-aid providers use the 2-thumb technique with a circumferential thoracic squeeze. Respiration is performed in a ratio of 3:1.

For children older than 1 year, the difference between adults is that respiration is attempted 5 times before the thoracic compressions are performed (100–120/min). Unlike with adults, professional assistants should attempt respiration in a ratio of 15:2, and untrained assistants in a ‘normal’ ratio of 30:2.

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