Airways

Similar consideration has been applied to bronchoconstriction elicited by mediators secreted from respiratory mast cells and circulating blood elements. Mast cell secretion is a dynamic process, which itself is regulated by endogenous secretory influences. Beta-adrenergic stimulation may substantially downregulate mast cell secretion of preformed mediators such as histamine13 and de novo synthesis of bronchoactive products […]

Under other circumstances, products of granulocytic infiltration and, perhaps, environmental insults (eg, ozone) elicit airway hyperreactivity that appears to be regulated at least in part by the bronchial epithelium. Neutrophilic infiltration appears to be an essential component of immune-mediated airway hyperreactivity in the rabbit. The major basic protein of eosinophils appears to augment airway contractility […]

Bronchomotor tone is the net product of moment-to-moment interactions between the autonomic nervous system, circulating humoral influences, and endogenous production of locally secreted mediators. Some degree of airway smooth muscle contraction exists in all individuals. In normal persons, it appears to result largely from parasympathetic innervation to the airway. Endogenous bronchomotor tone theoretically is antagonized […]

Although a prevalence rate for bronchospastic disorder in AIDS has been reported in an earlier study, the prevalence cited in that report (3 percent) was considerably lower than that found here, and, in fact, was close to the rate of airway hyperreactivity found in the general population. This discrepancy is not attributable to physiologic criteria […]

Relation of Abnormal Airways Function to Clinical Events We examined the temporal relationship of PFT results to episodes of Pneumocystis carinii pneumonia (PCP) and the presence of systemic Kaposis sarcoma (KS) for possible clues to the pathogenesis of airway dysfunction. Among the 99 AIDS patients reported here, 54 percent had developed PCE while 29 percent […]

Prevalence of Abnormal Airway Function in AIDS From January 1983 to July 1986, 105 AIDS patients were referred for pulmonary physiologic assessment. Ninety-nine (94.3 percent) of these individuals were able to perform three FVC maneuvers acceptable for analysis. The 105 patients referred to the PFT lab represent 68.6 percent of those with AIDS who were […]

A standard approach was employed in the assessment of forced expiratory flow rates. Flow rates were considered to be abnormally low if either the ratio of forced expiratory volume in 1 s (FEVJ to the forced vital capacity (FVC) or the mean forced expiratory flow during the middle half of the FVC (FEF 25-75%) was […]

Individuals with the acquired immunodeficiency syndrome (AIDS) are subject to frequent often fatal pulmonary complications. Infections 4*4e to a myriad of opportunistic and common pathogens as well as noninfectious processes such as majignancy and lymphocytic interstitial pneumonitis have been identified in this setting. In addition, anatomic obstruction of upper and central airways may occur as […]

Shapiro et al2 noted that the highest values for the work of breathing occur in the smallest endotracheal tubes. Moreover, they noted that at all levels of minute ventilation, work values were different between the different tube sizes tested. It could be argued that at low minute ventilations, this does not represent a clinically significant […]

Clinical Application How does this information relate to the clinical situation? Since fully developed flow regimens probably rarely occur in the tubes we use, the equations described form only an approximation of the truth. However, they indicate that the longer the tube, the greater the resistance—although one study in infant endotracheal tubes reported that the […]