Respiratory emergencies

Template:TOC-right In emergency medicine, ensuring the airway is not obstructed is usually the first priority in assessment and immediate measures. The mnemonic "ABCD" gives the immediate priorities:

• Airway: There must be a clear path from the nose or mouth to the lungs. Even if the patient is incapable of active breathing, air can be supplied externally, but if there is no way to oxygenate the blood, the brain will be irreparably damaged in 4-5 minutes at normal body temperature
• Breathing: If the patient is making no respiratory effort, oxygen can be supplied externally, initially by mouth-to-mouth artificial respiration, manual bag-valve-mask device, or a mechanical ventilator. When the patient is breathing ineffficiently, supplemental oxygen may be adequate, or it may be necessary to paralyze the respiratory muscles and take over mechanical ventilation.
• C:irculation. Blood needs to move, through regular or artificial heartbeat, or interventions to restore circulation.

Whenever there is even mild respiratory distress, emergency personnel must plan for contingencies; some conditions, such as anaphylactic shock can progress from itching and wheezing, to complete airway obstruction, in minutes.

If there is active respiratory distress or a strong index of suspicion that it is imminent, other supportive steps should be taken. A breathing patient should be put on oxygen. Establish at least two large-bore intravenous lines, draw several tubes of venous blood according to the local protocol, and attach the patient to a cardiac monitor-defibrillator. Attach a pulse oximeter, and, when available, a pulse capnometer. Take vital signs. Position the patient to assist respiration.

Immediate airway management

Without a patent airway, all other resuscitative efforts will be futile. The examiner begins by assessing the patient's level of consciousness and efficiency of breathing. If the patient is conscious, able to speak, not cyanotic, and has nonemergent vital signs and chest sounds, assessment can proceed to the evaluating urgent but not immediately life-threatening conditions.

The following conditions justify immediate intubation:

1. No breathing at all (apnea)
2. Glasgow Coma Scale < 9
3. Sustained seizure activity.
4. Unstable mid-face trauma.
5. Airway injuries.
6. Large flail segment or respiratory failure.
7. High aspiration risk.
8. Inability to otherwise maintain an airway or oxygenation.

Intubation

Intubation physically protects the airway from vomitus or other fluids being aspirated, and also acts as a mechanical "splint" inside it, protecting it from laryngospasm or laryngeal edema. While clinical judgment is always paramount, full endotracheal intubation may not be needed. Various less invasive oral or nasopharyngeal airway may provide adequate mechanical support, and require far less less technical skill to insert.

Preparation

• Rapid sequence intubation

Other immediate threats to life

Tension pneumothorax

Tension pneumothorax is far more severe than ordinary pneumothorax. In a conventional pneumothorax, air enters the chest cavity, which is normally at negative pressure relative to room air. In the less complicated types of pneumothorax, there is leakage in both directions. Tension pneumothorax, however, is caused by damage that creates a one-way valve effect, so the air pressure in the chest continues to increase, and can cause complete lung failure.

There is considerable controversy about its diagnosis and treatment, especially in the field. In principle, a large-bore hypodermic needle, equipped with a flutter valve that will let air out but not in, converts the condition to a regular pneumothorax. If the problem is indeed tension pneumothorax, and the needle is inserted in the correct place, the decompression can indeed be a lifesaving immediate intervention.

Diagnosis is not as clear-cut as textbooks sometimes suggest, and, in inadequately trained hands, the needle either may not reach the air pocket, or may damage other structures.

Severe pulmonary edema

Pulmonary edema can be due to direct lung disorders, or a consequence other disorders of fluid handling, especially heart failure. Cardiac etiology is most common, but primary lung disorders need specific handling; it is not impossible to have comorbid causes.

Severe asthma

Asthma is, when acquired, usually a lifelong disease. The standard of treatment is to suppress the hyperimmune response, which, through the release of inflammatory factors, will lead to increasing difficulty. Criteria for an immediate asthmatic crisis include an inability to speak and intense perspiration. If the patient has difficulty in speaking and still has trouble breathing when in an optimal resting position, consider the exacerbation as severy. According to the diagnostic criteria of the U.S. National Asthma Education and Prevention Program. Severe asthma has dyspnea at rest and can speak only with difficulty. The peak expiratory flow rate <40 percent predicted or personal best. The situation is Life threatening when respiratory distress makes it impossible to speak, the patient is perspiring, and the peak expiratory flow rate, if it can be taken, is <25 percent predicted or personal best.