Decompensation is usually due to worsening of airflow obstruction resulting from increased bronchospasm, superimposed respiratory infection or other respiratory pathology, interference with respiratory drive, cardiovascular deterioration, smoking, noncompliance with medications, noxious environmental exposures, use of medications that prevent bronchorrhea, and adverse responses to medication (e.g., anaphylactoid responses or b-adrenergic blockade). Disordered ventilatory drive most commonly arises from misuse of oxygen therapy, hypnotics, or tranquilizers. Metabolic disturbances, as well as inadequate oxygen delivery independent of respiratory function, may cause decompensated COPd.
Exacerbations of COPD usually involve progressive hypoxemia due to bronchospastic worsening of ventilation-perfusion matching. Signs of hypoxemia include tachypnea, cyanosis, agitation and apprehension, tachycardia, and systemic hypertension. The most life-threatening feature of decompensation is hypoxemia where arterial saturation falls below 90 percent. With increased work of breathing, muscle production of carbon dioxide increases and alveolar ventilation is often unable to increase to prevent carbon dioxide retention and respiratory acidosis. Signs of hypercapnia include confusion, tremor, stupor and, finally, hypopnea and apnea.
Patients usually complain of dyspnea and orthopnea. The intensified effort to ventilate is further dramatized by sitting-up-and-forward position, pursed-lip exhalation, accessory muscle use, and diaphoresis. Pulsus paradoxus may be noted during blood pressure recording. Complications such as pneumonia, pneumothorax, or an acute abdomen may be neglected or minimized by the patient's generalized respiratory distress, tachypnea, or global diminution of breath sounds.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...