This month's Editor's Choice, by Sahetya et al, is a small,prospective, physiologic study adjusting driving pressurethrough manipulation of positive end-expiratory pressure(PEEP). When the lowest driving pressure was reached,the stability over time was assessed. Compared to PEEPset using the low PEEP/FIO2 table from the ARDSnet, adecrease in driving pressure was associated with an increasein PEEP in 6 subjects and decrease in 4. Importantly, afterthe change in PEEP, driving pressure stabilized in less than5 minutes. Dries and Marini provide comment, noting thatthe best PEEP is tidal volume dependent. They argue for anempiric approach to PEEP, as the impact of PEEP on drivingpressure is related to lung recruitability.
Mechanical insufflation-exsufflation (MI-E) is standardcare in chronic neuromuscular diseases such as amyotrophiclateral sclerosis (ALS). MI-E operation has remained fairly constant since its inception. Recently, MI-E systemshave added oscillations in an effort to improve secretionclearance. Sancho and colleagues evaluated MI-E with andwithout oscillations in a 12-month study of subjects withALS. They found that the addition of oscillations had noimpact on the need for invasive procedures or incidenceof respiratory infections. Chatwin and Toussaint commentthat the study demonstrates that oscillations should not beroutinely adopted. However, they suggest that patients withbulbar involvement could respond differently.
Inay and colleagues measured the distribution ofventilation using electrical impedance tomography (EIT)during mechanical ventilation of pediatric subjects. Theyfound that the distribution of ventilation was more ventral in subjects receiving controlled ventilation. This was associated with poorer oxygenation. Spontaneous ventilationwas associated with more even distribution of ventilation and improved oxygenation. EIT provides information onventilation distribution, but the ability to use that informationto impact patient outcomes remains to be seen.
Wataru and others compared high flow nasal cannula(HFNC) to oxygen delivered by a large volume nebulizerfollowing extubation. This single center randomized controlled trial did not demonstrate any differences in re-intubation rate at day 7. HFNC provides advantages relatedto washout of deadspace versus standard oxygen therapy butthat did not result in outcome differences in this trial.
DalCorso et al evaluated a number of field walking testsin subjects with bronchiectasis. They found no differencein the desaturation events or peak heart rate between the6-minute walk test (6MWT), the incremental shuttle walktest, and endurance shuttle walk test, They concluded thatthese tests can be used interchangeably for evaluation ofexercise-induced desaturations.
Cammarota and colleagues compared setting PEEPusing gas exchange endpoints versus esophageal pressuremonitoring to obtain a positive transpulmonary pressureduring intraoperative ventilation. Targeting transpulmonarypressure was associated with improved oxygenation andbetter lung compliance. No postoperative outcome variableswere measured.
De Souza and others evaluated the intra- and inter-observer reproducibility of the timed inspiratory effort index (TIE). They previously reported that TIE may be a predictorof successful ventilator discontinuation. They report thatthere was a low variability between measurements and highreproducibility of the TIE measurement.
Donadio and coworkers evaluated the exercise capacityof subjects with cystic fibrosis during a modified shuttletest (MST). The distance walked was compared withanthropometric data and lung function. They report that themain determinants of exercise capacity assessed by the MSTwere resting heart rate, age and lung function.
Viral infections predominate the literature at this writing. Holzemer and others describe metapneumovirus (MPV) inhospitalized pediatric subjects. The authors performed aretrospective study in two centers evaluating demographics,comorbidities and treatments. Oxygen therapy met the needsof most subjects. They found that children with MPV were atincreased risk of acute kidney injury regardless of the degreeof respiratory illness.
Apropos to the current times, Jeong et al evaluated theimpact of breathing through an N95 facemask worn bysubjects with COPD. They measured respiratory symptomsand physiologic variables during a 10-minute period of restand during the 6MWT. Of 97 subjects, 7 were unable to wearthe mask for the entire study duration. Subjects unable tocomplete the study had a higher modified British MedicalResearch Council score and lower forced expiratory volumein 1 second. The authors conclude that more advanced COPD limits tolerability of the N95 mask for even short timeperiods.
Jin and colleagues evaluated a portable bluetooth spirometerto a traditional pulmonary function analyzer during pulmonaryfunction testing. Testing primarily evaluated flow measurements. The authors found that the concordance between devices was good. They speculate that the device may provide cost savingsand convenience.
Su et al provide a systematic review of probiotics forventilator associated pneumonia (VAP). Their meta-analysissuggests that probiotics may reduce VAP, but this needs to betested in large multi-center trials.
Epler and others provide a review of radiation post breastcancer radiotherapy and bronchiolitis obliterans organizingpneumonia (BOOP). BOOP is characterized by ground-glassopacities in the radiation-exposed lung and frequently in thenon-irradiated lung. They reported that risk factors for BOOPinclude increasing age, cigarette smoking, and increasingcentral lung distance.
Our Year in Review series includes neonatal respiratorysupport by Wheeler and Smallwood and aerosol therapy byBerlinski. Both describe important papers published on therespective topics in the last 12 months.
In a special article by Cobb and Solanki, the role ofE-cigarettes and vaping devices on acute lung injury aredescribed. This concise review separates fact from fictionrelated to the outbreak of e-cigarette associated lung injury(EVALI). The current corona virus has pushed EVALI off theradar, but it remains and important public health issue.
Our second Cochrane Corner is a review of noninvasive ventilation in cystic fibrosis by our Editorial Intern, DeniseWillis.
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