Pathophysiology

Respiratory failure: Inability of respiratory system to adequately oxygenate and/or ventilate, caused by problems like airway obstruction, parenchymal lung disease, respiratory muscle fatigue, or respiratory center depression

Shock: Inadequate tissue perfusion due to problems with intravascular volume, pump failure, or maldistribution of blood flow. Leads to cellular hypoxia, acidosis.

Cardiac arrest: Loss of effective cardiac mechanical activity, determined by lack of pulsations, unresponsiveness, and apnea. Results in global ischemia.

Bradycardia: Abnormally slow heart rate that reduces cardiac output. Poorly tolerated in pediatric patients.

Tachycardia: Abnormally rapid heart rate that can impair ventricular filling and coronary perfusion. Atrial/ventricular arrhythmias common causes.

Risk Factors and Triggers

• Respiratory failure: airway abnormalities, pulmonary infections, neuromuscular disorders, respiratory muscle fatigue, CNS depression
• Shock: dehydration, trauma, sepsis, cardiac disease, toxins, tension pneumothorax, cardiac tamponade
• Cardiac arrest: respiratory failure, shock, dysrhythmias, submersion injury, trauma, drug toxicity
• Bradycardia: hypoxemia, acidosis, hypoglycemia, hypothermia, drug effects, electrolyte abnormalities
• Tachycardia: hypoxemia, hypovolemia, fever, pain, medications, underlying heart disease