Showing papers by "Neil R. MacIntyre published in 2018"

Characterizing Nebulizer Performance for Methacholine Challenge Tests.

Abstract: NOTE: This editorial is not a component of the ERS technical standard on bronchial challenge testing that was endorsed by the American Thoracic Society in March 2017. Therefore, while the information contained within is consistent with the ERS technical statement, the editorial should not be considered an official position of either the ERS or ATS. Page 1 of 7 AJRCCM Articles in Press. Published on 30-August-2018 as 10.1164/rccm.201805-0942ED

The Long-Term Oxygen Treatment Trial for Chronic Obstructive Pulmonary Disease: Rationale, Design, and Lessons Learned

Abstract: The Long-Term Oxygen Treatment Trial demonstrated that long-term supplemental oxygen did not reduce time to hospital admission or death for patients who have stable chronic obstructive pulmonary disease and resting and/or exercise-induced moderate oxyhemoglobin desaturation, nor did it provide benefit for any other outcome measured in the trial. Nine months after initiation of patient screening, after randomization of 34 patients to treatment, a trial design amendment broadened the eligible population, expanded the primary outcome, and reduced the goal sample size. Within a few years, the protocol underwent minor modifications, and a second trial design amendment lowered the required sample size because of lower than expected treatment group crossover rates. After 5.5 years of recruitment, the trial met its amended sample size goal, and 1 year later, it achieved its follow-up goal. The process of publishing the trial results brought renewed scrutiny of the study design and the amendments. This article expands on the previously published design and methods information, provides the rationale for the amendments, and gives insight into the investigators' decisions about trial conduct. The story of the Long-Term Oxygen Treatment Trial may assist investigators in future trials, especially those that seek to assess the efficacy and safety of long-term oxygen therapy. Clinical trial registered with clinicaltrials.gov (NCT00692198).

Spirometric Volumes and Breathlessness Across Levels of Airflow Limitation : The COPDGene Study.

Abstract: Spirometric Volumes and Breathlessness Across Levels of Airflow Limitation : The COPDGene Study.

Pulmonary Delivery of Therapeutic and Diagnostic Gases.

Abstract: The 21st Congress for the International Society for Aerosols in Medicine included, for the first time, a session on Pulmonary Delivery of Therapeutic and Diagnostic Gases. The rationale for such a session within ISAM is that the pulmonary delivery of gaseous drugs in many cases targets the same therapeutic areas as aerosol drug delivery, and is in many scientific and technical aspects similar to aerosol drug delivery. This article serves as a report on the recent ISAM congress session providing a synopsis of each of the presentations. The topics covered are the conception, testing, and development of the use of nitric oxide to treat pulmonary hypertension; the use of realistic adult nasal replicas to evaluate the performance of pulsed oxygen delivery devices; an overview of several diagnostic gas modalities; and the use of inhaled oxygen as a proton magnetic resonance imaging (MRI) contrast agent for imaging temporal changes in the distribution of specific ventilation during recovery from bronchoconstriction. Themes common to these diverse applications of inhaled gases in medicine are discussed, along with future perspectives on development of therapeutic and diagnostic gases.

Ventilator Management Guided by Driving Pressure: A Better Way to Protect the Lungs?*

Abstract: 338 www.ccmjournal.org February 2018 • Volume 46 • Number 2 physician without non-ICU service obligations present in the ICU at night. The availability of intensivists on the weekend was never formally established in this study (8), although it is possible that hospitals with an intensivist at night also are likely to have one on the weekend. In studies conducted at hospitals with an on-site intensivist, there were no significant differences in patient mortality whether they were admitted on a weekday or a weekend (OR, 1.05; 95% CI, 0.98–1.13). Unfortunately, due to the heterogeneity and limitations in data reporting, it was not possible to estimate how much of the geographic component was accounted for by the presence of an on-site intensivist. The suggestion that an on-site intensivist is associated with lower mortality in patients admitted on weekends stimulates multiple questions about their protective role. Do they provide better recognition of critical illness, faster response to changes in clinical trajectory, decreased time to advanced procedures, or simply more manpower? Are all critical care providers (i.e., fellows, attendings) equal or is attending level experience important? Alternatively, could a critical care advanced practitioner provide the same benefit? Furthermore, it is unknown whether other factors such as a high patient-to-physician ratio, staff fatigue, or delays in obtaining diagnostic tests and procedures also play an important role. Although exact definitions vary between studies, a weekend consisting of the time period between 6 PM Friday and 8 AM Monday constitutes roughly 37% of an entire week. Hence, in an ICU environment where patients are unstable and disease trajectory unfolds rapidly over the course of a few short days, it is unsurprising to discover a higher mortality during the weekend particular to circumstances of lessened intensivist coverage. The data presented by Galloway et al (8) suggest that the sustained presence of trained, dedicated critical care practitioners during the weekend provides an incremental mortality benefit. The changes necessary to meet the challenge inherent in these findings will likely require a culture shift for both professional societies and individual practitioners.

Validation of spirometry prediction equations in western Kenya.

Abstract: Setting Community of Eldoret, Kenya. Objective To test the performance of three commonly used spirometry prediction equations in a healthy Kenyan population. Design Cross-sectional assessment of healthy adults in Eldoret. Results Of the 331 subjects enrolled in the study, 282 subjects aged 18-85 years (45% males, 55% females) produced high-quality spirograms. Lung function predictions were made using the Global Lung Initiative 2012 (GLI 2012) prediction equations for African Americans, the National Health and Nutrition Examination Survey III (NHANES III) prediction equations for African Americans, and the Crapo prediction equation. Bland-Altman analyses were performed to measure the agreement between observed and predicted spirometry parameters. Overall, the GLI 2012 and NHANES equations for African Americans performed similarly for forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), significantly overestimating FVC while accurately predicting observed FEV1 values. Conclusion The study brings into question the utility of three major spirometry prediction equations in a Kenyan population. The significant overestimation of FVC by the best-performing equations despite accurate prediction of FEV1 suggests poor performance of these equations in our population.

Airway pressure release ventilation: a step forward?

Abstract: Dear Editor, The trial by Zhou et al. [1] shows clinical benefit for airway pressure release ventilation (APRV) and is thus important. However, it comes from a single center and, because it was an unblinded study, the potential for bias in clinical decision-making during the trial is obvious. This does not mean bias was present, but these results must be replicated in multicenter studies before practice changes. Control group management may have been suboptimal because of the use of the low PEEP/FiO2 table from the original ARDS Network trial [2]. Studies subsequent to this trial (and a meta-analysis) suggest that tables using a higher PEEP structure in severe ARDS have outcome benefits over tables using lower PEEP [3]. The reported APRV plateau pressure (Pplat) is considerably lower than the Phigh. This makes little sense since there is no flow during much of Thigh, and thus Phigh by definition should equal Pplat. This discrepancy is likely explained by the reported APRV Pplat being calculated during a volume control breath with similar tidal volumes and set PEEP. This approach, however, ignores the inevitable auto-PEEP that would be present with APRV when using an early expiratory flow termination to set Tlow. This Pplat misrepresentation underscores how nuances of APRV may be underappreciated even by experienced users. Before we invest resources to implement APRV on a large scale, assurances are needed to be sure this investment is justified. This study represents a significant step in this process but many more steps need to be taken.

Optoacoustic Evaluation of Endotracheal Tube Depth in Pediatrics.

Abstract: Technological advancement is a cornerstone in the practice of respiratory care. Applying new technology to solve clinical problems requires careful investigation to ensure the safety and efficacy of new devices, protocols, and treatment modalities. New technologies are often rapidly incorporated

Airway Pressure Release Ventilation Letter-Reply.

Abstract: We thank Dr Light for his insights on airway pressure release ventilation (APRV)[1][1] and will address his comments one by one below. However, we first re-emphasize that the purpose of our study[2][2] was not to address the clinical value of APRV—that can only be accomplished with randomized