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Idiopathic pulmonary fibrosis (IPF) is a chronic progressive and ultimately fatal disease, the clinical course of which in individual patients is highly variable. Sudden deterioration of a patient's respiratory condition during a stable course is not uncommon. Many cases of uncertain etiology have been called acute exacerbation (AEx) of IPF, under the assumption of sudden acceleration of the underlying disease process. In recent years, several studies have reported the clinical significance of AEx-IPF. In 2007 Collard and colleagues created a Consensus Perspective, which proposed consensus definition and standard diagnostic criteria. This review primarily discusses studies performed after this Consensus Perspective., (Copyright © 2012 Elsevier Inc. All rights reserved.)

This article examines the features of nosocomial pneumonia in the subpopulation of patients with multiple trauma. Epidemiology, trauma-associated risk factors, diagnosis, microbiology, therapy, and prevention are reviewed. While some issues may overlap with critically ill patients in general, differences in approach and management will be discussed.

Acute respiratory failure in pregnancy is an important cause of maternal and fetal morbidity and mortality. Causes include: ARDS, venous air embolism, beta-adrenergic tocolytic therapy, asthma, thromboembolic disease, pneumothorax, and pneumomediastinum. The most common predisposing diseases for ARDS complicating pregnancy are sepsis, pneumonia, aspiration of gastric contents, and amniotic fluid embolism. Knowledge of normal maternal-fetal physiology and determinants of fetal oxygen delivery (uterine blood flow, placental transfer, fetal circulation) can help sustain normal fetal development, usually without compromising maternal care. The increased microvascular permeability seen in ARDS is likely mediated by neutrophils, proinflammatory mediators (e.g., tumor necrosis factor, interleukin-1, arachidonic acid metabolites) and activation of the complement cascade. Treatment of respiratory failure in pregnancy is largely supportive, including mechanical ventilation, hemodynamic support, nutrition, and prophylaxis against thromboembolism. No specific therapy has as yet been proven effective for ARDS, other than treating the underlying cause. Respiratory failure from status asthmaticus is treated with vigorous bronchodilator therapy, high-dose glucocorticosteroids, magnesium sulfate, and careful ventilator management. Occasionally, more experimental therapies (e.g., isoproterenol infusion, halothane anesthesia) are indicated. Certain strategies can help prevent respiratory failure from aspiration of gastric contents, beta-adrenergic tocolytic therapy, and thromboembolic disease.

The clinical presentation and course of chemical pneumonitis after inhalation of gastric contents ranges from mild and self-limited to severe and life-threatening, depending on the nature of the aspirate and the underlying condition of the host. In the absence of witnessed inhalation of vomit, diagnosis is difficult and requires a high index of suspicion in a patient who has risk factors for aspiration. In the absence of an obvious predisposition, the abrupt onset of a self-limited illness characterized by dyspnea, cyanosis, and low-grade fever associated with diffuse rales, hypoxemia, and alveolar infiltrates in dependent lobes should suggest aspiration. Treatment consists of supportive care with high-flow oxygen and volume replacement. Bacteria usually play no role in the initial lung injury, and antibiotics should be withheld until there is evidence of superinfection. Prophylactic corticosteroids should not be used. Preventive measures should be employed in patients at high risk for aspiration. Patients with unexplained chronic respiratory syndromes should be evaluated for gastric regurgitation and aspiration.

The evaluation and treatment of patients who complain of wheezing take on special significance in the elderly. Although asthma may begin late in life, it is distinctly uncommon. When it does, it is clinically undistinguishable from asthma present at an earlier age. If severe, the disease may require treatment with corticosteroids as well as bronchodilators. Any side effects are particularly troublesome in the elderly, and careful patient monitoring is essential. Wheezing in the elderly may also signal the onset of other diseases such as chronic obstructive pulmonary disease, congestive heart failure, pulmonary aspiration, pulmonary embolism, and bronchogenic carcinoma. Consideration of these causes of wheezing will lead to appropriate diagnostic studies and specific therapy.

Wheezes are defined as high-pitched, continuous, adventitious lung sounds. They are produced by oscillation of opposing airway walls whose lumen is narrowed. Although asthma is the most common cause of wheezing, a wide variety of disease processes may result in wheezing due to airway obstruction. This obstruction may be caused by airway edema, smooth muscle constriction, increased secretions, vascular congestion, mass lesions, scarring, or foreign bodies. Stridor is a special kind of wheeze described as a loud musical sound of constant pitch, which is heard in patients with tracheal or laryngeal obstruction. The full differential diagnosis of airway obstruction should be carefully considered in any patient with wheezing or stridor.