Elderly patients may be at greater risk for misdiagnosis and inappropriate treatment as a consequence of pulmonary function test underutilization and tests being conducted with low quality performance expectations. The study by Haynes sought to determine if elderly patients are able to achieve both spirometry and diffusion capacity (DLCO) quality scores comparable to a younger adult population. It was found that elderly patients referred to a hospital-based pulmonary function test lab can be expected to achieve spirometry and DLCO quality scores comparable to younger adult patients. As Sorenson points out in her editorial, this paper may be of interest primarily to those who perform PFTs, but the implications are far more global. These data should be used to promote and encourage physicians to appreciate the need for good quality pulmonary function studies in older adults.
Smith and colleagues compared inspiratory load compensation responses according to maximum inspiratory pressure and weaning outcome in difficult-to-wean ICU patients. Their results suggest that the inspiratory load compensation response is different in patients who are successfully liberated from mechanical ventilation and those who are not, reflecting dynamic inspiratory muscular efforts that could be influential on the ventilator weaning process. As pointed out by Sassoon, inspiratory muscle strength training has the potential to accelerate the ventilator liberation process. A large randomized controlled study with defined, standardized protocol is needed.
Russian et al calculated the internal volume and cross-sectional area of various endotracheal tube sizes, the external volume and cross-sectional area of various suction catheter sizes, and the ratio of suction catheter to endotracheal tube size. They also measured negative pressures created by suction in a lung model during multiple suction maneuvers. Volume and area calculations provided an alternative method for determining appropriate suction catheter size. A volume or area ratio of 50% corresponds to a diameter ratio of 70%. Negative pressures during suctioning remain low at the new ratios. Therefore, a larger suction catheter than recommended by current clinical practice guidelines allows adequate air passage between the catheter and endotracheal tube.
Heated humidification can be used during NIV, but little has been reported about the effects on the hygrometric conditions inside an oronasal mask and oral dryness during 24 hours on NIV. Oto et al measured absolute humidity inside oronasal masks on subjects with acute respiratory failure during 24 hours on NIV. AH varied among the subjects, and some complained of oral dryness even with heated humidifier. Oral breathing decreased oral moistness and worsened the feeling of dryness.
McNamara and colleagues conducted short-term 20-hour and long-term 10-week randomized crossover studies comparing a heated humidifier (HH) to a heat and moisture exchanger (HME) in children with established tracheostomies. Over 20 hours use, HH, compared to HME, improved work of breathing. Over a longer 10-week treatment period HH resulted in decreased adverse clinical events. This suggests that a HH is preferable to a HME in this patient population.
Smoking, depression, and anxiety increase the risk of death in patients with COPD, but the combined effect of these factors is unknown. Lou and colleagues found that smoking, depression, and anxiety were associated with higher risk of death in patients with COPD. The risk of death, depression, and anxiety increased with increasing years of smoking and cigarette pack-years.
Peripheral muscle dysfunction is a common finding in patients with COPD. Miranda et al compared muscle fatigue and recovery time between 2 representative muscles: the middle deltoid and the quadriceps femoris. They found that an upper limb muscle (middle deltoid) had a higher fatigability than a lower limb muscle (quadriceps femoris).
High-flow nasal cannula (HFNC) creates positive oropharyngeal airway pressure and improves oxygenation. It remains unclear, however, whether HFNC improves thoraco-abdominal synchrony in patients with mild to moderate respiratory failure. Using respiratory inductive plethysmography, Itagaki et al investigated the effects of HFNC on thoraco-abdominal synchrony. They found that HFNC improved thoraco-abdominal synchrony in adult subjects with mild to moderate respiratory failure.
Someya and colleagues studied potential predictors of exercise-induced oxygen desaturation in patients with systemic sclerosis. Logistic regression analysis showed the percent-ofpredicted DLCO as a highly accurate predictor of exercise-induced oxygen desaturation. This was useful as a predictor in over 80% of the subjects.
Bronchial variability in patients with COPD may be a phenotypic feature associated with clinical characteristics and differential treatment response. Ortega et al analyzed whether symptoms, quality of life, and exercise capacity varied in subjects with COPD as a function of bronchodilator test results, and compared responses to an exercise program. Compared to subjects with COPD and negative reversibility, those with positive reversibility walked for shorter distances, and had shorter endurance times and worse quality of life, but the improvements after exercise training were similar.
The purpose of the study by Kaminsky and colleagues was to determine whether there are distinguishing physiological characteristics of patients with discordance between percent-of-predicted peak work versus peak oxygen consumption, in order to understand how to use these measurements in interpreting exercise capacity. Their observation that there are distinguishing physiological features between those who have a higher peak work and those who have higher peak oxygen consumption provides insight into the underlying processes determining maximal exercise capacity.
To maximize the likelihood of successful long-term mechanical ventilation in patients with neuromuscular diseases, ventilator characteristics and settings must be chosen carefully, taking into account both medical requisites and the patient's preference and comfort. Lofaso and colleagues found that patients' and prescribers' opinions differed about the ideal home ventilator. Patients were less prone to use new technologies, mainly because of a lack of information, underlining the need for regular mechanical ventilation update in patients receiving long-term mechanical ventilation.
The goal of the study by Fitzgerald et al was to assess the clinical feasibility of high-frequency chest wall compression (HFCWC) therapy in neurologically impaired children with respiratory symptoms. They found that regular HFCWC therapy may reduce the number of hospitalizations in neurologically impaired children.
The impact of different CO2 exhalation systems and leaks on the actual FIO2 and gas exchange was evaluated by Storre and colleagues. The use of a leak port circuit and the occurrence of leak around the interface significantly reduced oxygen concentration at the mask and negatively impacted gas exchange in subjects receiving home NIV and supplemental oxygen.
There are few studies using animal models in chest physical therapy. Comaru et al aimed to develop a model of obstructive atelectasis induced by artificial mucus injection in the lungs of newborn piglets, for the study of neonatal physiotherapy. Their model of atelectasis in newborn piglets was feasible and appropriate to evaluate the impact of physical therapies on atelectasis in newborns.
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