This month's Editor's Choice article addresses the measurement of driving pressure (ΔP) during pressure support ventilation using an end-inspiratory hold. Perez and colleagues used esophageal manometry to measure ΔP and transpulmonary ΔP during patient-triggered breaths in ARDS subjects with varying PEEP levels. They found an association between ΔP and transpulmonary ΔP with a ΔP > 15 cm H2O as the best threshold for detecting transpulmonary ΔP ≥ 12cm H2O. They suggest that ΔP using an end-inspiratory hold might detect excessive transpulmonary ΔP. Zheng and Cortes-Puentes provide an accompanying editorial noting that previous work has shown that transpulmonary ΔP/ΔP determined from airway pressures is approximately 0.8 in patients with bilateral lung disease. They also point out that changes in abdominal and chest wall compliance may alter this relationship significantly. Finally, they state that these pressures cannot track regional ventilation and focal lung stress during the transition from controlled to patient-triggered approaches. They urge caution in relying on airway pressure measurements in these circumstances.
Henn and others report their findings from an online survey at two college campuses regarding the use of electronic nicotine delivery systems (ENDS) during the COVID-19 pandemic. One university was in the U.S. and the other in Germany. Approximately a third of respondents were using ENDS and most reported increased use during the pandemic. Stress relief and addiction were the most common reasons for increasing ENDS use. They suggest that ENDS use results in nicotine addiction and that mental health counseling could help reduce ENDS use. Goodfellow opines that vaping, while heralded as a potential method to reduce cigarette use, is often used in addition to traditional smoking. She notes that, in concert with mental health professionals, respiratory therapists (RTs) can play an important role in counseling students to reduce or eliminate ENDS addiction.
Nielsen et al describe the use of automated secretion removal technology in a small group of mechanically ventilated subjects. This automated cough procedure rapidly deflates the endotracheal tube (ETT) cuff during inspiration and rapidly inflates the cuff at the beginning of inspiration. They found that the cough procedure was effective in secretion removal in 90% of subjects and was well tolerated. The authors suggest that this could replace standard endotracheal suctioning. Li provides commentary, reviewing several methods described in the literature to remove secretions in intubated patients without ETT suctioning. She explains that shallow ETT suctioning is well-tolerated but while these cough maneuvers show promise, further human studies are needed.
Chiang and others performed a bench study of fugitive aerosols during aerosol therapy using different mask designs. They studied an aerosol mask, a modified non-rebreathing mask (no vent holes), and an aerosol mask with the vent holes covered by viral filters on either side. They found that the filtered mask reduced fugitive aerosols and that during treatment RTs should wear appropriate personal protective equipment and avoid standing parallel to the patient's head.
Feldman and colleagues performed a retrospective study of mechanically ventilated pediatric subjects who had a measurement of deadspace to tidal volume ratio (VD/VT) prior to extubation. They divided subjects into two groups, VD/VT < 0.30 and VD/VT ≥ 0.30. They recorded the level of post-extubation respiratory support at 1, 2, 3, 7 and 14 days. In a group of 54 subjects, they found that subjects with a VD/VT ≥ 0.30 had more days of post-extubation respiratory support and longer ICU stays.
Davis and others studied the impact of nocturnal high-flow nasal cannula (HFNC) on the sinonasal symptoms of subjects with cystic fibrosis during hospitalization for an exacerbation. Subjects received HFNC at 20 L/min or 5 L/min of low flow oxygen using a cold, bubble humidifier. There were no differences in sleep disturbances between groups, but sinonasal symptoms were only improved in subjects receiving HFNC.
Cushen et al compared bronchodilator delivered by a jet nebulizer to therapy using a vibrating mesh nebulizer (VMN) in a small group of subjects with COPD exacerbation. Spirometry, body plethysmography, and impulse oscillometry were performed and Borg breathlessness scores recorded pre-bronchodilator and 1-hour post-bronchodilator. Both groups showed similar changes in lung volumes and capacities. The Borg score was reduced in the VMN group.
Patrick and others conducted a prospective cohort analysis of pediatric and young adult subjects followed in a clinic for asthma on inhaled corticosteroid medication found to have poor inhaled corticosteroid refill persistence. This cohort received a follow-up telephone outreach call 5 to 8 weeks after the clinic visit. The primary outcome measure was refill persistence with regard to inhaled corticosteroid therapy. They reported that telephone outreach after outpatient clinic visits for asthma had short-term benefits in inhaled corticosteroid refill persistence.
Klein et al studied the minimally important difference of the 20-m, 6-min walk test (6MWT20) in subjects with COPD. They assessed lung function, activities of daily living (ADLs), functional capacity 6MWT20, dyspnea, health status, quality of life, and limitations in ADLs. The primary outcome was the 6MWT20 distance. They found that the 6MWT20 was responsive to pulmonary rehabilitation with an average improvement of 39 m and that the minimally important difference was 20 m.
Trottier and colleagues performed a randomized, controlled, crossover double-blind study on 10 healthy subjects with induced hypoxemia during spontaneous breathing with oxygen support, CPAP (5 cm H2O), and noninvasive ventilation (7/3 cm H2O). In random order, 3 dynamic hypoxic challenges of 5 min (FIO2 0.08, 0.11, and 0.14) were introduced. For each condition, automated oxygen titration and manual oxygen titration by experienced RTs with the aim to maintain SpO2 at 94 ± 2% were compared. Automated oxygen titrations maintained the SpO2 target in all three conditions and hyperoxia (SpO2 > 96%) less frequent. They concluded that automated control of oxygen flow was able to maintain the SpO2 at target more often than manual oxygen titration in this setting.
Mari and coworkers provide a short report on a calibration method to record the pressure-volume curve of the esophageal balloon. The method involves filling the balloon at a slow and continuous rate using an automatic process that doesn't require intervention during recording. Michaels et al author a short report consisting of a retrospective analysis to determine whether respiratory mechanics, oxygenation impairment, social demographics, and comorbid conditions among mechanically ventilated subjects suffering from COVID-19 infection are associated with all-cause mortality.
Finally, we publish four papers from our symposium Research and Publication in Respiratory Care. Miller contributes a paper on how to write an abstract for presentation at a scientific meeting. Goodfellow provides a paper on how to search the medical literature and write a review. Hess adds a review of the conduct and reporting of observational studies. Willis provides a paper on how to present your research findings at a scientific meeting.
- Copyright © 2023 by Daedalus Enterprises
