Respiratory arrest facts for kids
Respiratory arrest is a serious medical condition caused by apnea or respiratory dysfunction severe enough that it will not sustain the body (such as agonal breathing). Prolonged apnea refers to a patient who has stopped breathing for a long period of time. If the heart muscle contraction is intact, the condition is known as respiratory arrest. An abrupt stop of pulmonary gas exchange lasting for more than five minutes may permanently damage vital organs, especially the brain. Lack of oxygen to the brain causes loss of consciousness. Brain injury is likely if respiratory arrest goes untreated for more than three minutes, and death is almost certain if more than five minutes.
Damage may be reversible if treated early enough. Respiratory arrest is a life-threatening medical emergency that requires immediate medical attention and management. To save a patient in respiratory arrest, the goal is to restore adequate ventilation and prevent further damage. Management interventions include supplying oxygen, opening the airway, and means of artificial ventilation. In some instances, an impending respiratory arrest could be predetermined by signs the patient is showing, such as the increased work of breathing. Respiratory arrest will ensue once the patient depletes their oxygen reserves and loses the effort to breathe.
Respiratory arrest should be distinguished from respiratory failure. The former refers to the complete cessation of breathing, while respiratory failure is the inability to provide adequate ventilation for the body's requirements. Without intervention, both may lead to decreased oxygen in the blood (hypoxemia), elevated carbon dioxide level in the blood (hypercapnia), inadequate oxygen perfusion to tissue (hypoxia), and may be fatal. Respiratory arrest is also different from cardiac arrest, the failure of heart muscle contraction. If untreated, one may lead to the other.
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Signs and symptoms
One common sign of respiratory arrest is cyanosis, a bluish discoloration of the skin resulting from an inadequate amount of oxygen in the blood. If respiratory arrest remains without any treatment, cardiac arrest will occur within minutes of hypoxemia, hypercapnia or both. At this point, patients will be unconscious or about to become unconscious.
Signs and symptoms of respiratory compromise can differ with each patient. Complications from respiratory compromise are increasing rapidly across the clinical spectrum. While respiratory compromise creates problems that are often serious and potentially life-threatening, they may be prevented with the proper tools and approach. Appropriate patient monitoring and therapeutic strategies are necessary for early recognition, intervention and treatment.
Causes
- Airway obstruction: Obstruction may occur in the upper and lower airway.
- Upper airway: Obstruction of the upper airway is common in infants less than 3 months old because they are nose breathers. Nasal blockage may easily lead to upper airway obstruction in infants. For other ages, upper airway obstruction may occur from a foreign body or edema of the pharynx, larynx, or trachea. In cases of decreased or total loss of consciousness, the tongue can lose muscle tone and obstruct the upper airway. Other potential causes of obstruction include tumors of the upper respiratory tract (oral cavity, pharynx, larynx), bodily fluids (blood, mucus, vomit), and trauma to the upper airway. The most common type of tumor of upper respiratory tract is squamous cell carcinoma, with the greatest risk factors for this condition being alcohol and tobacco use, with HPV (genotype 16) being another important risk factor. An epidemiological study of over 5 million cases of head and neck trauma in the United States resulting in visits to the emergency department found that the majority occur due to falls or blunt force, with foreign body injuries being more common in the pediatric population.
- Lower airway: may occur from bronchospasm, drowning, or airspace filling disorders (e.g. pneumonia, pulmonary edema, pulmonary hemorrhage). Obstructive conditions of the lower airway, including severe asthma or COPD episodes, can also lead to respiratory arrest. During these episodes, known as exacerbations, airway resistance is increased due to inflammatory changes in the lungs. This leads to increased work of breathing and decreased oxygen delivery to tissue. In asthma, this involves bronchiolar constriction whereas in COPD this involves small airway collapse during expiration and subsequent air-trapping. One of the ways the body attempts to compensate for these increased respiratory demands is by increasing respiratory rate, which in turn worsens respiratory muscle fatigue of the diaphragm and can eventually lead to respiratory arrest and death without timely medical intervention.
- Decreased respiratory effort: Central nervous system impairment leads to decreased respiratory effort. The respiratory center of the brain is located in the pons and medulla and is primarily driven by elevated carbon dioxide levels in the blood (hypercapnia) with decreased oxygen levels (hypoxemia) serving as a less potent stimulus. Central nervous system disorders, such as stroke and tumors, may cause hypoventilation. Drugs may decrease respiratory effort as well. These lower respiratory drive by blunting the response of the respiratory center of the brain to hypercapnia. Metabolic disorders could also decrease respiratory effort. Hypoglycemia and hypotension depress the central nervous system and compromise the respiratory system.
- Respiratory muscle weakness: Neuromuscular disorders may lead to respiratory muscle weakness, such as spinal cord injury, neuromuscular diseases, and neuromuscular blocking drugs. Respiratory muscle fatigue can also lead to respiratory muscle weakness if patients breathe over 70% of their maximum voluntary ventilation. Breathing over an extended period of time near maximum capacity can cause metabolic acidosis or hypoxemia, ultimately leading to respiratory muscle weakness.
- Cardiac arrest (independent of the underlying reason) will lead to respiratory arrest within minutes.
Diagnosis
Diagnosis requires clinical evaluation, as detailed below.
Initial assessment
After determining the scene is safe, approach the patient and attempt to converse with him or her. If the patient responds verbally, you have established that there is at least a partially patent airway and that the patient is breathing (therefore not currently in respiratory arrest). If the patient is unresponsive, look for chest rise, which is an indicator of active breathing. A sternal rub is sometimes used to further assess for responsiveness. Initial assessment also involves checking for a pulse, by placing two fingers against the carotid artery, radial artery, or femoral artery to ensure this is purely respiratory arrest and not cardiopulmonary arrest. Checking a pulse after encountering an unresponsive patient is no longer recommended for non-medically trained personnel. Once one has determined that the patient is in respiratory arrest, the steps below can help to further identify the cause of the arrest.
Clearing and opening the upper airway
The first step to determining the cause of arrest is to clear and open the upper airway with correct head and neck positioning. The practitioner must lengthen and elevate the patient's neck until the external auditory meatus is in the same plane as the sternum. The face should be facing the ceiling. The mandible should be positioned upwards by lifting the lower jaw and pushing the mandible upward. These steps are known as head tilt, chin lift, and jaw thrust, respectively. If a neck or spinal injury is suspected, the provider should avoid performing this maneuver as further nervous system damage may occur. The cervical spine should be stabilized, if possible, by using either manual stabilization of the head and neck by a provider or applying a C-collar. The C-collar can make ventilatory support more challenging and can increase intracranial pressure, therefore is less preferable than manual stabilization. If a foreign body can be detected, the practitioner may remove it with a finger sweep of the oropharynx and suction. It is important that the practitioner does not cause the foreign body to be lodged even deeper into the patient's body. Foreign bodies that are deeper into the patient's body can be removed with Magill forceps or by suction. A Heimlich maneuver can also be used to dislodge the foreign body. The Heimlich maneuver consists of manual thrusts to the upper abdomen until the airway is clear. In conscious adults, the practitioner will stand behind the patient with arms around the patient's midsection. One fist will be in a clenched formation while the other hand grabs the fist. Together, both hands will thrust inward and upward by pulling up with both arms.
Treatment
Treatment varies depending on the cause of respiratory arrest. In many cases, it is necessary to establish an alternate airway and providing artificial ventilation that can include modes of mechanical ventilation.
See also
- Crash cart
- Respiratory failure
