History
Consideration of the questions that follow can help guide the history in a patient with possible respiratory failure.
Does the patient have factors that increase the risk for respiratory failure? Factors may include any of the following:
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Young age
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Premature birth
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Immunodeficiency
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Chronic pulmonary, cardiac, or neuromuscular disease (eg, cystic fibrosis, bronchopulmonary dysplasia, unrepaired congenital heart disease, spinal muscular atrophy [SMA])
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Anatomic abnormalities
Does the patient have a cough, rhinorrhea, or other symptoms of an upper respiratory tract infection? These manifestations may help in defining an etiology.
Does the patient have a fever or signs of sepsis? Several infections can lead to respiratory failure because of a systemic inflammatory response, pulmonary edema, or acute respiratory distress syndrome (ARDS) or because of a power-load imbalance secondary to increased oxygen consumption. Epiglottitis from Haemophilus influenzae type b infection, although decreased in recent years owing to widespread immunization, is a classic cause of obstructive respiratory failure in infants and children.
How long have the symptoms been present?
The natural course of a respiratory illness must be considered. Respiratory syncytial virus (RSV) infections, for example, frequently worsen over the initial 3-5 days before improvement occurs.
Does the patient have any pain? Pain can suggest pleuritis or foreign-body aspiration.
Does the patient have a possible or known exposure to sedatives (eg, benzodiazepines, tricyclic antidepressants, narcotics) or has he or she recently undergone a procedure that used general anesthesia? This could suggest hypoventilation.
Does the patient have symptoms of neuromuscular weakness or paralysis? What is the distribution of weakness and duration of symptoms to narrow the differential diagnosis? Bulbar dysfunction suggests myasthenia gravis. Distal weakness that progresses upward suggests Guillain-Barré syndrome. Apnea associated with a traumatic injury suggests a cervical spinal cord injury.
Does the patient have a history suggestive of a stroke or seizure?
Does the patient have a history of headaches? With chronic hypercapnia, headaches typically occur at nighttime or upon the patient's awakening in the morning.
Physical Examination
During the physical examination, the clinician should avoid interfering with the patient's mechanisms for compensation. Children often find the most advantageous position for breathing, which can be a helpful diagnostic clue for the astute clinician.
Children with respiratory distress commonly sit up and lean forward to improve leverage for the accessory muscles and to allow for easy diaphragmatic movement. Children with epiglottitis sit upright with their necks extended and heads forward while drooling and breathing through their mouths. Making a child lie down or making him or her cry during the simplest examination can precipitate acute respiratory failure.
Patients may be lethargic, irritable, anxious, or unable to concentrate. The inability to breathe comfortably creates anxiety, and superimposed hypoxemia and hypercapnia accentuates any restlessness and agitation. Increased agitation may indicate a general worsening of the patient's condition.
The clinician should observe whether the patient appears well or sick, and should look for central or peripheral cyanosis.
The respiratory rate and quality can provide diagnostic information, and they should be assessed with attention to age-specific norms for each particular patient. Bradypnea is most often observed in central control abnormalities. Slow and large tidal volume breaths also minimize turbulence and resistance in significant extrathoracic airway obstruction (eg, epiglottitis). The fast and shallow breathing of tachypnea is most efficient in intrathoracic airway obstruction. It decreases dynamic compliance of the lung.
Auscultation provides information about the symmetry and quality of air movement. Evaluate the patient for stridor (an inspiratory sound), wheezing (an expiratory sound), crackles, and decreased breath sounds (eg, alveolar consolidation, pleural effusion).
Grunting is an expiratory sound made by infants as they exhale against a closed glottis. It is an attempt to increase functional residual capacity and lung volume. This is done in order to raise functional residual capacity above the critical closing volume and to avoid alveolar collapse. This physical finding represents impending respiratory failure and should not be overlooked.
Assess for accessory muscle use and nasal flaring, as well as for respiratory effort. Suprasternal and intercostal retractions are present when high negative pleural pressures are required to overcome airway obstruction or stiff lungs.
Evaluate for paradoxical movement of the chest wall. In the presence of abnormalities of the pulmonary pump, paradoxical chest-wall movement occurs because of instability of the chest wall associated with absent intercostal muscle use. As the diaphragm contracts and pushes abdominal contents out, the chest wall retracts inward instead of expanding normally. Termed abdominal breathing, this, however, may be a normal compensatory pattern for a very young infant with chronic lung disease or decreased chest wall compliance.
Tachycardia and hypertension may occur secondary to increased circulatory catecholamine levels. A gallop is suggestive of myocardial dysfunction leading to respiratory failure. Age-specific bradycardia associated with decreased or shallow breathing and desaturations noted via pulse oximeter is ominous and indicates the need for emergent positive-pressure ventilation.
Peripheral vasoconstriction may develop secondary to respiratory acidosis and/or hypoxia.
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Pediatric Respiratory Failure. Bilateral airspace infiltrates on this chest radiograph film were secondary to acute respiratory distress syndrome that resulted in respiratory failure.
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Pediatric Respiratory Failure. Extensive left-lung pneumonia caused respiratory failure; the mechanism of hypoxia is intrapulmonary shunting.
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Pediatric Respiratory Failure. A bilevel positive airway pressure (BIPAP) support machine is shown. It could be used in spontaneous mode or timed mode (the backup rate could be set).
