This month's Editor's Choice by Lamb et al evaluates high-flow nasal cannula (HFNC) therapy following ventilator liberation. One group received HFNC immediately following extubation, while the other only if O2 requirement was > 4 L/min. Early use of HFNC was associated with a decrease in pulmonary infection and a reduction in the use of bronchodilator therapy. The second group demonstrated shorter ICU stay and fewer hospital days. Dries suggests that early use of HFNC could facilitate secretion clearance with a potential decrease in pulmonary pathogens and exposure to gramnegative bacteria. These findings support the growing use of HFNC as a form of noninvasive respiratory support in the ICU.
Takamitsu and colleagues compared ambient noise levels of 3 HFNC systems with and without the use of a filter. The Venturi HFNC systems created the highest noise levels, which were attenuated by use of a filter. The HFNC system with an integral compressor had the lowest noise level. These systems can create noise levels equivalent to a garbage disposal. Itagaki and Nishimura point out that these levels exceed those recommended, and that improvements in respiratory function must be balanced against the potential negative impact on the body as a whole.
Noninvasive ventilation (NIV) has been one of the important advances in mechanical ventilation over the past 2 decades. Long-term NIV has shown advantages for patients with neuromuscular disease (NMD), but success over time remains a concern. Suh and colleagues evaluated the 5-year maintenance rates of NIV in 180 subjects with NMD. They found that NIV was applied for a similar duration across most of the subjects with continued success for the 5-year study period. However, progression of ALS requires increased support, including transition to invasive ventilation. Boussaid and coworkers discuss this natural progression of ALS and how, despite a desire to avoid tracheostomy, invasive ventilation plays an important role in prolonged treatment.
Prolonged mechanical ventilation (PMV) as a marker of chronic critical illness is a consequence of improved ICU care. Herer and Bertrand found that PMV was associated with weaning failure, readmissions and mortality. A third of PMV subjects required readmission to the ICU in the first year. These data suggest caution regarding PMV and the value of assessing patient-important outcomes.
Berlinski and colleagues evaluate the shaking and actuation of pMDI on the emitted dose of fluticasone with a holding chamber. They demonstrate that delays between shaking and actuating a corticosteroid suspension resulted in an increase in the emitted dose of the second actuation. This may occur commonly with pMDI administration with a holding chamber. This work highlights the importance of caregiver and patient education on pMDI use.
Awad and Berlinski evaluated the impact of jet nebulizer/compressor combinations on albuterol delivery. They measured flow and pressure generated by the compressor and nebulizer particle size output with various nebulizer/compressor combinations. Their results suggest that nebulizer brand is more important than compressor brand on inhaled mass and particle size. They caution caregivers to be aware of unintended consequences when altering compressor/nebulizer combinations.
Sanservino et al compared the self-selected walking speed in healthy subjects and subjects with COPD. By assessing O2 consumption normalized by mass and distance, they found that COPD subjects had an increase in dyspnea sensation with increased walking speed. They conclude that subjects with COPD choose their walking speed according to a tolerable dyspnea sensation and that interventions affecting dyspnea and gait might improve quality of life.
The incremental shuttle walk test can be administered using a treadmill or in a hallway. In either case, the results are used to tailor the exercise prescription. Oliveira and colleagues compared these methods in subjects with bronchiectasis and found that the methods were not interchangeable. There was an increased walking distance using the treadmill, but similar physiologic responses. These data are important in assessing the response to aerobic training.
Exercise training improves strength and quality of life in patients with COPD. In 16 subjects with COPD, Leite et al evaluated the critical velocity in a non-exhaustive (CVNE) manner as a surrogate for anaerobic threshold test. While subjects tolerated exercise at CVNE and there were good correlations with V̇O2 and heart rate, the tests were not reliably reproduced. The CVNE has the potential advantage of allowing the patient to perform at sub-maximal exertion. Further investigation to tailor this method for COPD is warranted.
Travel with portable O2 improves the quality of life for patients requiring long-term O2 therapy. Campbell and colleagues surveyed a group of subjects receiving long-term O2 therapy regarding planning travel with O2 and their travel experiences. In 50 subjects who responded to the survey, only a quarter had traveled by air. The majority found it complicated to organize their trip and difficult to find information regarding travel with O2. Yet over 80% said they would fly again. Education of subjects regarding air travel with O2 should be provided for all ambulatory patients.
The accuracy of O2 flow meters is assumed and calibration of these devices is typically not within the caregiver's purview. Duprez et al evaluated the accuracy of O2 flow delivered from O2 cylinders in prehospital and hospital emergency care. They evaluated flows from 2–12 L/min. Their results suggest that most flow meters provide flows sufficiently accurate for clinical use. They did find that single stage regulators were less accurate at low flows and low cylinder pressures. The accuracy of flow meters appears to be a relatively unimportant factor affecting O2 therapy.
Cacau et al compared the maximum 6-min walk distance in healthy children in Brazil. In a study of nearly 1,500 subjects, they established reference values. Boys walked slightly further than girls. The strength of the study is in the sample size and use of volunteers from a large country with varying climatic, socioeconomic, and cultural regions.
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