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Rationale: Colder temperatures have been shown to increase hospitalization and mortality rates in adults with chronic obstructive pulmonary disease (COPD) and cardiac disease. Seasonal influences on exacerbation rates in adults with severe COPD but without significant cardiovascular disease are unclear. In addition, regional variations in COPD exacerbations in North America have not yet been explored., Objectives: In this study, we sought to determine the seasonal and regional variability in exacerbation rates in those with COPD but without significant cardiovascular risk factors., Methods: We studied adults without cardiovascular risk factors from STATCOPE (Simvastatin in the Prevention of COPD Exacerbations) and placebo arm of MACRO (Azithromycin for the Prevention of Exacerbations of COPD) studies. Forty-five study sites were divided into climate regions in Canada and the United States; seasons were defined as winter, spring, summer, and fall. The primary outcome was the rate of COPD exacerbation. Secondary outcomes included time to first exacerbation, severity of exacerbations, all-cause mortality, and antibiotic and steroid use., Results: We analyzed 1,175 subjects with a mean age of 63.3 ± 8.6 years, forced expiratory volume in 1 second of 41.5 ± 17.1% predicted, and 53.6 ± 29.4 pack-years of smoking history. The COPD exacerbation rate was higher in winter (0.13 exacerbations/person-month) than in spring, summer, and fall (0.11, 0.079, and 0.10 exacerbations/person-month, respectively) (P < 0.001). Summer had the highest proportion of severe exacerbations (40.5%) compared with spring, fall, and winter (32.6%, 34.7%, and 33.1%, respectively) (P = 0.004). Mortality was highest in spring and winter (34% and 30%, respectively). There was significant regional variability in the time to first exacerbation, with the Southeast and West having longer median times to first exacerbation (350 and 342 d, respectively, compared with 184 d in other regions) (P < 0.001)., Conclusions: Significant seasonal and regional variability exist in the rate and severity of exacerbations and overall mortality in adults with COPD without cardiovascular disease.

Rationale: Between 10% and 57% of lung transplant (LTx) recipients develop primary graft dysfunction (PGD) within 72 hours of LTx. PGD is clinically and histologically analogous to the acute respiratory distress syndrome. In patients at risk for or with acute respiratory distress syndrome, lung-protective ventilation strategies (low tidal volume and positive end-expiratory pressure) improve outcomes. There is, however, little information available on mechanical ventilation strategies after LTx., Objectives: Our aim in this international survey was to describe the current practices of mechanical ventilation immediately after LTx., Methods: An electronic survey was sent to the medical and surgical directors of U.S. LTx programs (n = 111) and to members of the Pulmonary Council of the International Society for Heart and Lung Transplantation (n = 470)., Results: A total of 149 individuals from 18 countries responded to the questionnaire. The most common modes of ventilation were pressure assist/control (37%) and volume assist/control (35%). Tidal volumes were most often determined by recipient characteristics. Donor characteristics were rarely considered (35%) and were infrequently known by the team managing the ventilator (42%). When presented with a choice of ideal tidal volumes, a majority of respondents selected 6 ml/kg recipient predicted body weight (58%), fewer selected 10 ml/kg (21%), and none selected 15 ml/kg. A majority preferred limiting the fraction of inspired oxygen rather than positive end-expiratory pressure (PEEP) (69% versus 31%, P = 0.006). The median minimum PEEP was 5 cm H2O, and the median maximum PEEP was 11.5 cm H2O. The presence of PGD increased the perceived importance of monitoring plateau pressure to adjust tidal volumes. The median plateau pressure limit perceived as a threshold triggering reduction in tidal volume was 30 cm H2O., Conclusions: Most respondents reported using lung-protective approaches to mechanical ventilation after lung transplantation. Low tidal volumes based on recipient characteristics were frequently chosen. Donor characteristics often were not considered and frequently were not known by the team managing mechanical ventilation after LTx.

Rationale: The association between a high predicted total lung capacity (pTLC) ratio (equal to pTLC(donor)/pTLC(recipient)), suggestive of an oversized allograft, with improved survival after lung transplantation (LTx) remains controversial., Objectives: To characterize donor-recipient lung size matching based on the pTLC ratio and to investigate the relationship of the pTLC ratio with post-LTx survival., Methods: All subjects in the Scientific Registry of Transplant Recipients, who underwent first-time LTx in the lung allocation score-based system between May 4, 2005 and March 31, 2012, were studied, and the pTLC ratio was calculated on the basis of sex, height, and age. Risk of death after LTx was analyzed using Cox proportional hazards models., Measurements and Main Results: The pTLC ratio was available for 10,289 of the 10,318 study subjects (99.7%). The mean pTLC ratio was 1.015 ± 0.175 (interquartile range, 0.918-1.119). Univariate analysis showed that the pTLC ratio was strongly associated with death in the first LTx year (P < 0.0001). With the pTLC ratio entered as a spline there was a nonlinear association with declining risk of death with higher pTLC ratio from 0.5 to about 1.3, where an inflection occurred with rising risk at higher values. Accounting for the pTLC ratio, recipient and donor sex were not independently associated with death after LTx. A change of pTLC ratio from 0.918 to 1.119 (the interquartile range) was associated with similar point estimates of reduced risk of death at 1 year in univariate (hazard ratio, 0.78) and comprehensive risk-adjusted multivariate models (hazard ratio, 0.86)., Conclusions: The pTLC ratio is an independent predictor of death in the first year after LTx and explains the association of sex with survival after LTx. Incorporating the pTLC ratio in the lung allocation mechanism could improve outcomes after LTx.