Our Editor's Choice paper this month, by Pintado et al, is a randomized controlled study to evaluate the effect of setting an individualized level of PEEP at the highest compliance. Subjects with ARDS were randomized to either a compliance-guided PEEP group or an FIO2-guided group. Multiple organ-dysfunction-free days, respiratory-failurefree days, and hemodynamic-failure-free days were significantly lower in subjects with compliance-guided setting of PEEP. Keenan and Dries suggest that this approach is clinically feasible but more labor intensive than following the PEEP/FIO2 table developed by the ARDS Network study group. That may be true, but compliance-based PEEP titration is less labor intensive than many other strategies that have been suggested for this purpose.
Vandenberghe and colleagues assessed factors that predict good tolerance of noninvasive ventilation (NIV) in subjects with amyotrophic lateral sclerosis (ALS). Multivariate analysis identified 3 factors predicting good NIV tolerance: absence of airway secretion accumulation (odds ratio 11.5); normal bulbar function (odds ratio 8.5); and older age (odds ratio 1.1). Although these data should not be used to select patients for treatment with NIV, it does identify patients who may require closer monitoring and a more aggressive approach to airway clearance therapy. A survey of Italian practice related to ALS care is reported by Vitacca et al. Vital capacity and arterial blood gases were measured regularly, respiratory muscle function and cough ability were routinely assessed in more than 85% of the units, and 94% of the units provided NIV. Aboussouan and Mireles- Cabodevila remind us that improved survival and improved quality of life are now well established benefits of NIV. In part due to the increased use of NIV in these persons, more patients with progressive neuromuscular diseases live longer, with better quality of life, and in their homes.
Heat and moisture exchangers (HMEs) can be applied to spontaneously breathing tracheostomized patients, but their performance in this role has not yet been clarified. Chikata et al carried out a bench study to investigate the effects of spontaneous breathing parameters and oxygen flow on the humidification performance of 11 HMEs. Absolute humidity differed among HMEs applied to tracheostomized patients with spontaneous breathing. Absolute humidity decreased when tidal volume increased, and increased at a higher respiratory rate. When oxygen was used, absolute humidity decreased to less than 30 mg/L for all the HMEs. These data suggest caution when applying HME to tracheostomized spontaneously breathing patients. Van den Boer and colleagues report a novel, simplified ex vivo method for measuring water exchange performance of HMEs with tracheostomy application. They found that assessment of the weight change between end of inhalation and end of exhalation is a valid and simple method of measuring the water exchange performance of an HME. Cuquemelle and Lellouche point out that this method is original and relatively simple, and it may be useful for HME evaluation. However, additional validations with other hygrometric methods and with other HMEs are required.
White and colleagues evaluated bronchodilator delivery during simulated pediatric NIV. They assessed albuterol delivery, with a vibrating-mesh nebulizer, at 3 different positions and exhalation leak valve combinations during simulated pediatric NIV. Greater albuterol mass was delivered with the nebulizer integrated into the mask than at any other testing condition. This suggests that a vibrating-mesh nebulizer placed in the mask may provide a better alternative for medication delivery.
The use of CPAP in patients with obstructive sleep apnea (OSA) is not always well tolerated. Salepci et al prospectively assessed factors that affect adherence in patients with OSA. Of the subjects enrolled who attended follow-up sessions, subjective adherence was 85% and objective adherence was 65%. Younger subjects adhered better to therapy. The most important factors that correlated with adherence were substantial improvement of daytime sleepiness and effect of CPAP on satisfactory sleep.
A bench study of 2 ventilator circuits during NIV with a helmet was conducted by Ferrone et al. Helmet NIV with the double tube circuit showed better patient-ventilator interaction. These results have implications for the clinical application of NIV when a helmet is used. The benefit of pulmonary rehabilitation in patients with COPD and normal exercise capacity is reported by Lan and colleagues. They enrolled 20 subjects with COPD and normal exercise capacity. They found that exercise training can result in significant improvement in health-related quality of life, exercise capacity, respiratory muscle strength, and exertional dyspnea in subjects with COPD and normal exercise capacity.
Sibila et al assessed the effects of prior inhaled corticosteroid (ICS) use on severity of illness and microbiology in community-acquired pneumonia (CAP) hospitalized patients. They found that prior ICS use was associated with higher severity of illness at admission and higher incidence of antimicrobial-resistant pathogens in CAP hospitalized patients. Crisafulli et al evaluated a new scoring system for the risk of oxygen desaturation during walking in COPD patients. They found that their walking desaturation score accurately predicts and classifies the risk of walking desaturation in COPD patients. Yang and colleagues investigated factors affecting CPAP acceptance in elderly patients with OSA. They found that CPAP acceptance, instead of CPAP adherence, is the critical issue with elderly patients with OSA.
Predictors and outcome of early-onset pneumonia after outof- hospital cardiac arrest was assessed by Pabst et al. The rate of early-onset pneumonia was not significantly influenced by the exchange of the pre-clinically inserted endotracheal tube, but was associated with longer need for mechanical ventilation and ICU stay. Pulmonary function and flow-volume loop patterns in patients with tracheobronchomalacia was studied by Majid and colleagues. They found that flow-volume loops were normal in a substantial number of patients with moderate to severe tracheobronchomalacia, and should not be used to decide whether it is present or clinically important. MicroRNA expression aberration associated with bronchopulmonary dysplasia (BPD) in preterm infants was investigated by Wu et al, who identified blood-based microRNAs associated with BPD. This might provide information regarding the roles of these biomarkers in the development of BPD in very low birthweight preterm infants. Porot and Guérin performed a bench assessment of a new insufflation-exsufflation device. The found a greater peak expiratory flow with the Nippy Clearway device than with the CoughAssist at low respiratory-system compliance, a finding that will need to be confirmed clinically.
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