Respiratory care
-
We evaluated the outcome of subjects with ARDS in relation to etiology and severity in a retrospective cohort study of the ARDS Network randomized controlled trials. The primary outcome was 28-d mortality. The secondary outcomes were 60-d mortality and ventilator- and ICU-free days. For severity of ARDS, subjects were stratified according to PaO2/FIO2. The etiology of ARDS was classified into sepsis, pneumonia, aspiration, trauma, and others. ⋯ Severity of ARDS based on PaO2/FIO2 did not impact 28-d mortality, ventilator-free days, or ICU-free days. Among the etiologies of ARDS, trauma subjects had the lowest 28- and 60-d mortality, whereas subjects with aspiration had more ICU-free days and ventilator-free days.
-
Significant concern exists regarding the respiratory health of military personnel deployed to Southwest Asia, given their exposures to numerous environmental hazards. Although the deployed military force is generally assumed to be fit, the pre-deployment respiratory health of these individuals is largely unknown. ⋯ Pre-deployment evaluation of military personnel identified numerous soldiers with active pulmonary symptoms and abnormal spirometry. When combined with questions regarding asthma history, wheezing and exercise intolerance, spirometry may identify individuals at risk for deployment-related respiratory complaints.
-
Spirometric Z-scores from the Global Lung Initiative (GLI) rigorously account for age-related changes in lung function and are thus age-appropriate when establishing spirometric impairments, including a restrictive pattern and air-flow obstruction. However, GLI-defined spirometric impairments have not yet been evaluated regarding associations with static lung volumes (total lung capacity [TLC], functional residual capacity [FRC], and residual volume [RV]) and gas exchange (diffusing capacity). ⋯ A GLI-defined spirometric restrictive pattern is strongly associated with a restrictive ventilatory defect (decreased TLC, FRC, and RV), while GLI-defined spirometric air-flow obstruction is strongly associated with hyperinflation (increased FRC) and air trapping (increased RV and RV/TLC). Both spirometric impairments were strongly associated with impaired gas exchange (decreased hemoglobin-adjusted single-breath diffusing capacity).
-
Albuterol hydrofluoroalkane (HFA) either alone or with a valved holding chamber is used to treat bronchoconstriction. Delays between actuation and inhalation are common. Currently, the recommended interval between actuations of an albuterol HFA is 60 s. Using a shorter interval when multiple actuations are ordered will improve productivity in the hospital setting. ⋯ Decreasing the interval between actuations from 60 to 30 and 15 s does not seem to affect the aerosol characteristics of ProAir and Ventolin. Although some changes were noticed for Proventil, the pMDI outperformed Ventolin that had the lowest fine-particle mass. The use of a valved holding chamber increased fine-particle mass, but introducing a 10-s delay between actuation and inhalation significantly reduced fine-particle mass.
-
Dynamic hyperinflation is a common cause of dyspnea and functional limitation in patients with emphysema. Dynamic hyperinflation occurs in individuals with air-flow limitation when expiratory time is decreased during periods of relative tachypnea (such as during exercise or agitation, for example). In this setting, patients with emphysema develop lung hyperinflation, impairment of inspiratory respiratory muscles, and an increase in work of breathing. ⋯ The inability of the respiratory system to respond to signals of increased demand (eg, by enlarging tidal volume and increasing inspiratory flow) results in a dissociation between afferent and efferent signaling thereby intensifying breathing discomfort, or what clinicians term dyspnea. A thorough understanding of the physiology of dyspnea and pathophysiology of dynamic hyperinflation informs the interventions used to mitigate sensations of dyspnea and the physiologic effects of dynamic hyperinflation, respectively. Pharmacotherapy, pulmonary rehabilitation, breathing techniques, positive airway pressure, and lung volume reduction are well-studied interventions that target pathways to dyspnea in patients with dynamic hyperinflation.