OBJECTIVES

Explain how multiple sources of oxygen supply to the lung prevents pulmonary infarction in most patients sustaining a pulmonary embolus. Explain the role of the Valsalva maneuver in precipitating pulmonary embolism in the postoperative patient. Outline the immediate emergency treatment for catastrophic pulmonary embolism. Describe the pathological alterations following pulmonary embolism, including increased dead space, V/Q abnormalities, and right ventricular failure. Describe the mechanism producing pulmonary hypertension following pulmonary embolism, and explain how this can cause right heart failure. Discuss the relationship between systemic hypotension and right ventricular ischemia, decreased cardiac output, and arrhythmias following pulmonary embolism. Describe how a low mixed venous oxygen saturation contributes to hypoxemia during pulmonary embolism. Discuss general principles of anticoagulant therapy, including dosing regimens, appropriate monitoring of lab values, and nursing considerations. List ECG changes commonly associated with pulmonary embolism. Discuss the role of streptokinase, urokinase, and tissue plasminogen activator as thrombolytic agents following pulmonary embolism. Discuss the mechanisms producing increased work of breathing and marked negative intrapleural pressures during status asthmaticus. Explain alterations in V/Q relationships typical of asthma, including both pathological as well as compensatory responses. Identify mechanisms producing increased pulmonary vascular resistance during an acute asthma attack. Define pulsus paradoxicus and explain its physiologic basis in the patient with status asthmaticus. Explain why a rising PaCO2 is an ominous clinical finding in the patient with status asthmaticus. Explain why pulmonary edema may occur in acute severe asthma. Discuss the pharmacologic management of status asthmaticus, including: Beta-2 agonists, corticosteroids, theophylline, anticholinergics, and others. Explain the rationale for administering a fluid bolus immediately prior to initiating mechanical ventilation of the patient in status asthmaticus. Discuss the role of permissive hypercapnia during mechanical ventilation of the patient with status asthmaticus. Examine the significance of PEEP and auto-PEEP in the patient with status asthmaticus. List clinical signs of severe airway obstruction and impending cardiac arrest in the patient with status asthmaticus. Explain why maintenance of cerebral blood flow during CPR is difficult in the patient with status asthmaticus. Define and discuss the following general pulmonary abnormalities in the surgical patient: impaired diffusion, V/Q mismatch, alveolar hypoventilation, increased pulmonary shunt, decreased oxygen delivery, pulmonary hypertension, decreased hypoxic pulmonary vasoconstriction, and atelectasis. Identify the causes of atelectasis in the postoperative patient, and describe its clinical presentation. Describe the role of incentive spirometry, CPAP mask, and IPPB in preventing postop atelectasis. Review factors predisposing the postoperative patient to bacterial pneumonia. Describe the clinical presentation and pathogenesis of the acid aspiration syndrome in the surgical patient. Describe the etiology of cardiogenic pulmonary edema as a postoperative complication. Outline the sequence of events leading to nosocomial pneumonia in the postoperative patient. Describe the pathologic changes seen in the lungs of a patient with COPD. Differentiate asthma from COPD. Troubleshoot the peripheral nerve stimulator when a 0/4 response to the train-of-four is elicited. Review research findings regarding instillation of normal saline during routine suctioning of an endotracheal tube. Maximize effectiveness of suctioning with an in-line suction catheter. List steps that should be taken to ensure accuracy of values obtained with a pulse oximeter.