Showing papers in "Respiratory Care in 2019"

High-Flow Nasal Cannula Oxygen Therapy Devices.

Abstract: For hypoxemic respiratory failure, the frontline treatment is supplemental oxygen. Since ARDS was first described, mechanical ventilation via an endotracheal tube (invasive ventilation) has no doubt saved many patients. During the 1990s, noninvasive ventilation was found to be superior to invasive ventilation for exacerbations of COPD, acute cardiogenic pulmonary edema, and acute respiratory failure in patients who were immunocompromised. In the 2000s, less invasive high-flow nasal cannula (HFNC) therapy gained attention as an alternative means of respiratory support for patients who were critically ill. The HFNC system is simple: it requires only a flow generator, active heated humidifier, single heated circuit, and nasal cannula. While NIV interfaces add to anatomic dead space, HFNC delivery actually decreases dead space. Although the use of HFNC in adults who are critically ill has been dramatically increasing, the advantages and disadvantages of each element have not been well discussed. For now, although functional differences among the different HFNC systems seem to be minor, to avoid adverse clinical events, it is essential to know the advantages and disadvantages of each element.

Impact of Electronic Cigarettes on Various Organ Systems.

Abstract: The electronic cigarette (e-cigarette) has been regarded by many as a healthier alternative to the combustible cigarette, yet there is a lack of consensus concerning the health consequences and the health benefits associated with e-cigarette use. We review the research on the effects of e-cigarettes on multiple physiological systems, examine the association between e-cigarette use and combustible cigarette uptake and cessation, and highlight research necessary to build consensus. Although the levels of known toxicants and carcinogens tend to be significantly lower in e-cigarettes than in combustible cigarette smoke, toxicants in e-cigarette e-liquid and those that form as part of the vaporization process may produce adverse health consequences in their own right. Acute effects have been noted in the pulmonary, cardiovascular, and immune systems, which highlight the need for research on long-term exposure. The specific chemical constituents and the levels of those constituents that pose harm remain largely uncharacterized. In addition, the efficacy of e-cigarettes for smoking cessation has yet to be established. As the e-cigarette has evolved rapidly, so has the methodology across studies, making cross-study comparisons more difficult to synthesize. The latest generation of e-cigarette devices deliver nicotine and toxicants at higher levels than earlier devices, especially in experienced users. E-cigarettes pose a risk for nicotine exposure, dependence, and combustible cigarette uptake. E-cigarettes and their delivered toxicants appear harmful to multiple organ systems, although the current body of evidence is limited, especially in terms of long-term effects. Further research is warranted with a focus on individual devices, e-liquid constituents, user characteristics, and patterns of use. Any potential benefit of e-cigarettes for smoking cessation must be weighed against the risks. Given the potential longer-term effects, efforts to prevent e-cigarette use in youth are critical.

Physiologic Effects of Noninvasive Ventilation.

Abstract: Noninvasive ventilation (NIV) has a number of physiologic effects similar to invasive ventilation. The major effects are to augment minute ventilation and reduce muscle loading. These effects, in turn, can have profound effects on the patient's ventilator control system, both acutely and chronically. Because NIV can be supplied with PEEP, the maintenance of alveolar recruitment is also made possible and the triggering load imposed by auto-PEEP can be reduced. NIV (or simply mask CPAP) can maintain upper-airway patency during sleep in patients with obstructive sleep apnea. NIV can have multiple effects on cardiac function. By reducing venous return, it can help in patients with heart failure or fluid overload, but it can compromise cardiac output in others. NIV can also increase right ventricular afterload or function to reduce left ventricular afterload. Potential detrimental physiologic effects of NIV are ventilator-induced lung injury, auto-PEEP development, and discomfort/muscle overload from poor patient-ventilator interactions.

Aerosol Delivery Through an Adult High-Flow Nasal Cannula Circuit Using Low-Flow Oxygen.

Abstract: BACKGROUND: There has been a growing trend toward delivering aerosolized medications using high-flow nasal cannula (HFNC). In some cases, patients who do not require high-flow oxygen to maintain adequate oxygenation may benefit from aerosol delivery while receiving low-flow oxygen via HFNC. The objective of this study was to quantify and compare the relative pulmonary and systemic delivery of salbutamol, with 2 different nebulizers, in patients with COPD receiving low-flow oxygen therapy through an HFNC. METHODS: Subjects were randomized to receive study doses of 5 mg salbutamol nebulized by either a jet nebulizer or a vibrating mesh nebulizer with a T-piece or spacer on days 1, 3, and 5 of admission. Subjects using the large spacer also received 2 puffs (100 μg each) of salbutamol via a pressurized metered-dose-inhaler prior to the nebulizer dose. Urinary salbutamol excretion 30 min post-inhalation and pooled samples of urinary salbutamol excretion up to 24 h post-inhalation were measured. On day 2, ex vivo studies were performed with salbutamol collected on filters placed between the HFNC and nebulizer, with drug eluted from filters and analyzed to determine inhaled dose. RESULTS: Twelve subjects (6 females), age 51.3 ± 11.2 y, were included. The vibrating mesh nebulizer demonstrated higher urinary salbutamol excretion at 30 min and 24 h post-inhalation compared to a jet nebulizer (P = .001 and P = .02, respectively). No significant difference was found between the T-piece and large-spacer configurations, even though the spacer provided a significantly larger emitted aerosol dose at the opening of the HFNC (P = .002). CONCLUSIONS: Aerosolized medication could be efficiently combined with low-flow oxygen, via HFNC, in COPD subjects without the need to interrupt the gas supply. The vibrating mesh nebulizer delivered larger doses to subjects compared to the jet nebulizer. However, there was no benefit of using the large spacer with HFNC in low-flow delivery, because the small inner diameter of the HFNC does not allow larger aerosol droplet sizes (preserved by the spacer) to reach the subject.

Peak Oxygen Uptake and Mortality in Cystic Fibrosis: Systematic Review and Meta-Analysis.

Abstract: BACKGROUND: Aerobic fitness, as measured by peak oxygen uptake (VO2 peak), correlates with survival in children and adults with cystic fibrosis (CF) We sought to evaluate the effects of VO2 peak on mortality rates in subjects with CF METHODS: An online search in PubMed, Embase, LILACS, and SciELO databases was conducted, and cohort studies that assessed mortality rates after oxygen absorption measurements during a maximal exercise test were included Data were extracted independently by 2 reviewers The quality analysis of the selected articles was performed using the Newcastle-Ottawa scale The main outcome evaluated was the mortality of subjects with CF Whenever possible, and if appropriate, a random effect meta-analysis was performed RESULTS: Six cohort studies were included in this systematic review including 551 subjects Five studies were classified with high methodological quality Two analyses were carried out to evaluate the influence of VO2 peak on mortality Total difference standardized mean between VO2 peak averages in the survival or non-survival groups was −0606 (95% CI = −0993 to −0219, P = 002) In addition, subjects with a lower VO2 peak had a significantly higher mortality risk (relative risk 4896, 95% CI = 1086 to 22072, P = 039) in an 8-y follow-up period CONCLUSION: Low levels of peak oxygen uptake are associated with an increase of 49 in the risk of mortality in subjects with CF This indicates that VO2 could be an important follow-up variable to measure, in addition to FEV1

Ventilator-Associated Events: What They Are and What They Are Not.

Abstract: In 2013, the United States Centers for Disease Control and Prevention redefined surveillance for quality of care in ventilated patients by shifting from ventilator-associated pneumonia (VAP) definitions to ventilator-associated event (VAE) definitions. VAE definitions were designed to overcome many of the limitations of VAP definitions, including their complexity, subjectivity, limited correlation with outcomes, and incomplete capture of many important and morbid complications of mechanical ventilation. VAE definitions broadened the focus of surveillance from pneumonia alone to the syndrome of nosocomial complications in ventilated patients, as marked by sustained increases in ventilator settings after a period of stable or decreasing ventilator settings. Qualitative studies suggest that most VAEs are caused by pneumonia, fluid overload, ARDS, and atelectasis. Only about 40% of clinically diagnosed VAPs meet VAE criteria, likely because the VAE requirement for a sustained increase in ventilator settings sets a threshold effect that selects for patients with severe disease. VAEs are associated with a doubling of the risk of death compared to patients without VAEs and compared to patients who meet traditional VAP criteria. Risk factors for VAEs include sedation with benzodiazepines or propofol, volume overload, high tidal-volume ventilation, high inspiratory driving pressures, oral care with chlorhexidine, blood transfusions, stress ulcer prophylaxis, and patient transport. Potential strategies to prevent VAEs include minimizing sedation, paired daily spontaneous awakening and breathing trials, early mobility, conservative fluid management, conservative transfusion thresholds, and low tidal-volume ventilation. A limited number of studies that have tested subsets of these interventions have reported substantial decreases in VAEs; no group, however, has thus far assessed the impact of a fully optimized VAE prevention bundle that includes all of these interventions upon VAE rates and other outcomes.

Diaphragmatic Ultrasound Assessment in Subjects With Acute Hypercapnic Respiratory Failure Admitted to the Emergency Department.

Abstract: BACKGROUND: Early identification of noninvasive ventilation (NIV) outcome predictors in patients with COPD who are experiencing acute hypercapnic respiratory failure consequent to exacerbation or pneumonia is a critical issue. The primary aim of this study was to investigate the feasibility of performing diaphragmatic ultrasound for excursion, thickness, and thickening fraction in highly dyspneic subjects with COPD admitted to the emergency department for exacerbation or pneumonia, before starting NIV (T0) and after the first (T1) and second hour (T2) of treatment. Secondarily, we determined whether these variables predicted early NIV failure. METHODS: Adult subjects with COPD admitted to the emergency department for exacerbation or pneumonia requiring NIV were eligible. Right-sided diaphragmatic excursion, bilateral thickness, thickening fraction, and arterial blood gas analyses were performed at T0, T1, and T2. Feasibility was estimated by considering the number of subjects whose diaphragmatic function could be evaluated at each time point. At T2, subjects were classified in 2 subgroups according to early NIV failure, which was defined as the inability to achieve a pH ≥ 7.35; the ability to achieve pH ≥ 7.35 indicated NIV success. RESULTS: Of the 22 subjects enrolled, 21 underwent complete diaphragm ultrasound evaluation (ie, right excursion and bilateral thickness at T0, T1, and T2) for a total of 63 excursion and 126 thickness assessments. At T2, 12 NIV successes and 9 NIV failures were recorded. Diaphragmatic excursion was greater in NIV successes than in NIV failures at T0 (1.92 [1.22–2.54] cm versus 1.00 [0.60–1.41] cm, P = .02), at T1 (2.14 [1.76–2.77] cm versus 0.93 [0.82–1.27] cm, P = .007), and at T2 (1.99 [1.63–2.54] cm versus 1.20 [0.79–1.41] cm, P = .008), respectively. Diaphragmatic thickness and thickening fraction were similar in both groups. CONCLUSIONS: In our emergency department setting, diaphragm ultrasound was a feasible and reliable tool to monitor highly dyspneic acute hypercapnic respiratory failure subjects with COPD undergoing NIV. (ClinicalTrials.gov registration NCT03314883.)

Ventilator-Induced Lung Injury: Classic and Novel Concepts

Abstract: Ventilator-induced lung injury (VILI) is a central confounder to improving outcomes from use of positive-pressure ventilation in critical illness. Therefore, with increasing use of positive-pressure ventilation, awareness to prevent VILI has grown. Because VILI cannot be diagnosed at the bedside, its prevention can only be attained by identifying the clinical mechanisms of harm, such as high tidal volume, high plateau pressure, and so forth, which, in turn, are derived from decades of laboratory work. The practice of positive-pressure ventilation has undergone a significant change; most important in the past decade is the preference to use noninvasive ventilation. Although noninvasive ventilation prevents the complications of intubation, it has potential to cause harm, especially in patients with de novo respiratory failure. This review covers some of the classic and emerging concepts of VILI genesis and their role during noninvasive ventilation. Combined modulation of these mechanisms could have a potential to impact outcomes.

Effects of Diaphragmatic Breathing With and Without Pursed-Lips Breathing in Subjects With COPD

Abstract: BACKGROUND: Breathing exercises, such as diaphragmatic breathing and pursed-lips breathing, play a role in some individuals with COPD and might be considered for those patients who are unable to exercise. However, in the literature are reports of some adverse effects of diaphragmatic breathing in patients with COPD. Thus, the purpose of this study was to assess the effects of diaphragmatic breathing and diaphragmatic breathing combined with pursed-lips on chest wall kinematics, breathlessness, and chest wall asynchrony in subjects with COPD, and also to assess whether the combination of both exercises reduces the adverse effects of diaphragmatic breathing while maintaining its benefits. METHODS: Seventeen subjects with COPD, mean ± SD, 65 ± 7 y of age, with a history of smoking and clinical stability without hospitalization or symptoms of exacerbation in the past 4 wk, were evaluated. On day 1, participants9 characteristics were collected, and they learned diaphragmatic breathing and its combination with pursed-lips breathing. On day 2, the participants were evaluated by optoelectronic plethysmography with the participants in the seated position while performing breathing exercises. RESULTS: Diaphragmatic breathing and diaphragmatic breathing plus pursed-lips breathing promoted a significant increase in chest wall tidal volume and its compartments as well as a reduction in breathing frequency compared with quiet breathing. No significant changes were observed in dyspnea or end-expiratory volume of the chest wall. A significant increase in asynchrony (inspiratory-expiratory phase ratio) was observed during diaphragmatic breathing and diaphragmatic breathing plus pursed-lips breathing compared with quiet breathing, with no differences observed between the exercises. CONCLUSIONS: Despite the increase in asynchrony, both breathing exercises were able to improve chest wall volumes without affecting dyspnea. The combination of exercises maintained the benefits but did not reduce the adverse effects of diaphragmatic breathing.

Health-Related Quality of Life in Adolescents and Adults With Cystic Fibrosis: Physical and Mental Health Predictors.

Abstract: BACKGROUND: People with cystic fibrosis face substantial physical, psychological, and social challenges as they move into adolescence and adulthood, which are likely to impact on their health-related quality of life. This study sought to examine the relative importance of physical and mental health variables associated with health-related quality of life in this group. METHODS: Adults and adolescents (N = 174; ≥14 y old) from across 11 adult or pediatric cystic fibrosis clinics in the Republic of Ireland, completed a background questionnaire that contained self-reported physical health variables, pulmonary function (ie, FEV1%) and body mass index. Questionnaire packs also contained the Hospital Anxiety and Depression Scale (HADS) and the Cystic Fibrosis Questionnaire-Revised, which has been specifically designed to assess health-related quality of life in patients with cystic fibrosis. RESULTS: HADS depression and/or anxiety scores were negatively associated with 11 of the 12 Cystic Fibrosis Questionnaire-Revised domain scores. FEV1% was positively associated with 8 domains when controlling for HADS anxiety but only 4 domains when controlling for HADS depression. HADS anxiety and depression scores demonstrated larger effect sizes and explained a greater proportion of the variance than pulmonary function in 8 of the 12 Cystic Fibrosis Questionnaire-Revised domain scores. CONCLUSIONS: Mental health variables, depression and anxiety, were strongly associated with health-related quality of life in subjects with cystic fibrosis and demonstrated greater effect sizes and explained a higher proportion of the variance overall than the physical health indicators, FEV1% and body mass index, which highlighted the importance of screening for, and treating, depression and anxiety symptoms.

Ventilator Bundles in Transition: From Prevention of Ventilator-Associated Pneumonia to Prevention of Ventilator-Associated Events.

Abstract: Implementation of ventilator bundles is associated with reductions in ventilator-associated pneumonia (VAP). However, the new surveillance model of ventilator-associated events (VAEs) has shifted the focus from VAP to objective, generalized signs of pulmonary decompensation not specific to VAP. This raises the question of whether the ventilator bundle also is effective in reducing VAE. This narrative review examined 6 studies published since 2013 that assessed the impact of ventilator bundles on the incidence of VAE, and a seventh study that examined its impact on mortality. All 7 studies were low-level evidence, and only 1 study was prospective. The findings among the studies were inconsistent, and the only prospective study found no difference in bundle adherence between those who did and did not develop VAE. However numerous factors may explain the apparent lack of efficacy. Most of these factors were related to the retrospective nature of the studies, such as suboptimal documentation of bundle procedures and the presence of potential non-modifiable risk factors, as well as insufficient performance of most bundle components. In some studies, low VAE incidence also raised uncertainty about the veracity of results. Despite these limitations, there was evidence suggesting that stress ulcer prophylaxis may increase VAE risk, and oral care with chlorhexidine may increase both VAE and mortality risk. The largest study found significant reductions in duration of intubation with weaning, sedation, and head of bed elevation, as well as reduced mortality risk with weaning and sedation bundle elements. Nonetheless, these studies should be useful in designing future prospective controlled studies to determine what elements of a future prevention bundle might be effective in reducing VAEs. At this juncture, and based on the limited evidence to date, it appears that incorporating daily sedation interruptions and spontaneous breathing trials are the factors most likely to reduce VAEs.

The Use of High-Flow Nasal Cannula Oxygen Outside the ICU

Abstract: BACKGROUND: High-flow nasal cannula (HFNC) oxygen therapy is a routine, evidence-based treatment in the ICU. Due to its ease of application, non– evidence-based use of HFNC has spread to non-ICU wards. This study reports on the experience with HFNC outside the ICU. METHODS: This is an observational study of HFNC prescribed by treating physicians in non-ICU areas. Primary outcomes included change in dyspnea visual analog scale score and physiological variables both before and 30 min after initiation of HFNC treatment. Secondary outcomes included mortality, ICU admission, and intubation. RESULTS: We observed decreased median (interquartile range) visual analog scale scores after initiation of HFNC: 8 (6–9) versus 5 (4–6) (P CONCLUSIONS: HFNC outside the ICU was associated with improved visual analog scale score, breathing frequency, and saturation but with a relatively high mortality, even in non-DNR subjects. HFNC was used in many subjects who had a DNR order. This therapy may have been palliative in intent. Care should be exercised in using this therapy in a setting that is not continuously monitored.

Minimum Clinically Important Difference in 30-s Sit-to-Stand Test After Pulmonary Rehabilitation in Subjects With COPD.

Abstract: BACKGROUND: The sit-to-stand (STS) test is a feasible tool for measuring peripheral muscle strength of the lower limbs. There is evidence of increasing use of STS tests in patients with COPD. We sought to evaluate in subjects with COPD the minimum clinically important difference in 30-s STS test after pulmonary rehabilitation. METHODS: Stable COPD subjects undergoing a 30-s STS test and a 6-min walk test (6MWT) before and after pulmonary rehabilitation were included. Responsiveness to pulmonary rehabilitation was determined by the change in 30-s STS test results (Δ 30-s STS) before and after pulmonary rehabilitation. The minimum clinically important difference was evaluated using an anchor-based method. RESULTS: 96 subjects with moderate-to-severe COPD were included. At baseline, 30-s STS test results were significantly related to distance covered in a 6MWT (6MWD) (r = 0.65, P CONCLUSIONS: Our study indicates that in stable subjects with moderate-to-severe COPD, the 30-s STS test was a sensitive tool to assess the efficacy of pulmonary rehabilitation. A Δ 30-s STS of ≥ 2 repetitions represented the minimum clinically important difference, which may be predicted by the baseline ability in the 30-s STS test and lung function in terms of diffusing lung capacity (ClinicalTrials.gov registration NCT03627624).

Respiratory Care of Patients With Neuromuscular Disease.

Abstract: Neuromuscular diseases are a heterogeneous group of neurologic diseases that affect a number of neural structures including the motor nerves, neuromuscular junctions, or the muscles themselves. Although many of the diseases are rare, the total number of individuals who present to a pulmonologist or respiratory care provider is significant. Approaches to care include regular and careful clinical follow-up of symptoms of sleep-disordered breathing, daytime hypoventilation, as well as cough and swallowing effectiveness. Noninvasive support with nocturnal mask ventilation and a pressure support device can be extraordinarily helpful and delay daytime ventilatory failure. When daytime ventilatory failure develops, other noninvasive methods are available for portable assistance. Support of cough function with manual assistance, a resuscitator bag, and/or mechanical insufflation-exsufflation can help prevent and treat infection. Referral for swallowing evaluation and treatment is very important for those with impaired bulbar function. This comprehensive respiratory care approach to individuals with neuromuscular disease and respiratory system involvement is essential to maintaining the health and longevity of these individuals.

Lung Ultrasound Combined With Procalcitonin for a Diagnosis of Ventilator-Associated Pneumonia

Abstract: BACKGROUND: Lung ultrasound is a valuable imaging tool in the diagnosis of community-acquired pneumonia. However, its diagnostic accuracy in ventilator-associated pneumonia (VAP) has not been fully investigated. The aim of this study was to evaluate the diagnostic performance of the combination of a lung ultrasound with procalcitonin (PCT) in mechanically ventilated subjects with symptoms suggestive of pneumonia. METHODS: A prospective study of 124 subjects with suspected VAP in 2 multidisciplinary ICUs was conducted between December 2016 and October 2017. Lower respiratory tract specimens were collected from all the subjects at enrollment and on the following 3 d. PCT assays were performed within 1 h of enrollment. Lung ultrasound and then computed tomography of the chest were performed within 24 h to detect lung consolidations. The subjects were divided into VAP and non-VAP groups according to the results of a computed tomography of the chest and semi-quantitative culture of the lower respiratory tract sample. RESULTS: A total of 124 subjects were included (48 in the VAP group and 76 in the non-VAP group). A positive lung ultrasound result combined with PCT of ≥0.25 ng/mL diagnosed VAP, with a sensitivity and specificity of 81.3 and 85.5%, respectively. The area under the receiver operating characteristic curve was significantly higher for lung ultrasound combined with PCT than for a white blood cell count, PCT, C-reactive protein, or Clinical Pulmonary Infection Score alone. CONCLUSIONS: A combination of lung ultrasound and PCT was accurate in the diagnosis of VAP. Lung ultrasound is a useful lung-imaging tool to assist VAP diagnosis.

Effects of Transitional Care on Hospital Readmission and Mortality Rate in Subjects With COPD: A Systematic Review and Meta-Analysis

Abstract: BACKGROUND: Studies on the effect of transitional care on hospital readmissions have reported inconsistent findings, and the effect on mortality has not been reviewed systematically. This systematic review and meta-analysis of randomized controlled trials aims to examine the effect of transitional care interventions on COPD-related readmissions, all-cause hospital readmissions, and all-cause mortality rates in subjects with COPD. METHODS: Electronic databases (CINAHL, Embase, Scopus, MEDLINE, Cochrane, PubMed, Web of Science, Airity, BMJ Respiratory Research Journal, and National Digital Library of Theses and Dissertations) were searched from inception to April 26, 2017. Online searches were conducted using key words and MeSH terms for COPD and transitional care. Entry terms for searching included chronic obstructive pulmonary disease, COPD, COPD transitional care or care transition, continuity of patient care, patient discharge, and patient transfer. The quality of the included trials was assessed using the Cochrane Collaboration tool. RESULTS: 13 randomized controlled trials met the inclusion criteria. Transitional care significantly reduced the risk of COPD-related readmissions (odds ratio = 0.599, 95% CI 0.421–0.852) and all-cause hospital readmissions (odds ratio = 0.720, 95% CI 0.531–0.978), but not that of all-cause mortality (odds ratio = 0.863, 95% CI 0.576–1.294) in subjects with COPD. The effects of transitional care on hospital readmissions were moderated by the duration of interventions, type of care providers, and use of telephone follow-up as an element of the intervention. CONCLUSIONS: There was a significant effect of transitional care on both COPD-related and all-cause hospital readmissions in subjects with COPD. Duration of interventions, type of care providers, and use of telephone follow-up appeared to moderate the beneficial effects of transitional care.

Neurally-Adjusted Ventilatory Assist for Noninvasive Ventilation via a Helmet in Subjects With COPD Exacerbation: A Physiologic Study.

Abstract: BACKGROUND: In patients with COPD exacerbation, noninvasive ventilation (NIV) is strongly recommended. NIV is generally delivered by using patient triggered and flow-cycled pressure support through a face mask. A specific method to generate neurally-controlled pressure support has been shown to improve comfort and patient-ventilator interaction. In addition, the helmet interface was better tolerated by patients compared with a face mask. Herein, we compared neurally-controlled pressure support through a helmet with pressure support through a face mask with respect to subject comfort, breathing pattern, gas exchange, pressurization and triggering performance, and patient-ventilator synchrony. METHODS: Two 30-min trials of NIV were randomly delivered to 10 subjects with COPD exacerbation redundant: (1) pressure support through a face mask with inspiratory pressure support of ≥8 cm H2O to obtain a tidal volume of 6–8 mL/kg of ideal body weight; and (2) NAVA through a helmet, setting the neurally-adjusted ventilatory assist level at 15 cm H2O/μV, with an upper airway pressure limit to obtain the same overall airway pressure applied during pressure support through a face mask. We assessed subject comfort, breathing frequency, respiratory drive, arterial blood gases, pressure-time product (PTP) of the first 300 ms and 500ms after initiation of subject effort, inspiratory trigger delay, and rate of asynchrony determined as the asynchrony index. RESULTS: Median and interquartile range NAVA through a helmet improved comfort (7.0 [6.0–8.0]) compared with pressure support through a face mask (5.0 [4.7–5.2], P = .005). The breathing pattern was not different between the methods. Respiratory drive was slightly, although not significantly, reduced (P = .19) during NAVA through a helmet in comparison with pressure support through a face mask. Gas exchange was also not different between the trials. The PTP of the first 300 ms (P = .92) and PTP of the first 500 ms (P = .08) were not statistically different between trials, whereas triggering performance, patient-ventilator interaction, and synchrony were all improved by NAVA through a helmet compared with pressure support through a face mask. CONCLUSIONS: In the subjects with COPD with exacerbation, NAVA through a helmet improved comfort, triggering performance, and patient-ventilator synchrony compared with pressure support through a face mask.

Non-Pharmacological Interventions to Prevent Ventilator-Associated Pneumonia: A Literature Review

Abstract: Ventilator-associated pneumonia (VAP) is a well-known complication of invasive mechanical ventilation in critically ill patients. The presence of an endotracheal tube (ETT) is one of the major culprits for VAP development: air flow moves pathogens toward the distal airways, while clearance of the trachea is blunted due to reduced tracheal ciliary movement and impaired cough. Several measures are recognized as being useful to prevent VAP, and these are usually grouped in a VAP bundle (ie, avoiding intubation or re-intubation whenever possible; head of bed elevation; hand hygiene; shortening ventilation through sedation interruptions, spontaneous breathing trials, or thromboembolic prophylaxis). However, other interventions have been proposed to reduce VAP rate; some of these interventions have been reported in large clinical trials to be effective, some have been evaluated in small observational studies, and still others at a pre-clinical stage. Some strategies aim to improve the ETT design via a subglottic drainage system, with treatment of the ETT surface to reduce pathogen activity, or by modification of the cuff shape or cuff material to provide a better seal. Another proposed strategy is improving airway care through control of cuff pressure, cleaning the ETT, or use of closed suction systems. Other interventions target a patient's position in the bed to reduce aspiration of digestive content in the airways, or the use of probiotics to modulate gastric flora. Some of these measures are supported by strong evidence, but the impact on relevant outcomes such as duration of ventilation or mortality, as well as cost-benefit ratio, is still unclear, resulting in lack of widespread use.

Improving Simulated Pediatric Airway Management in Community Emergency Departments Using a Collaborative Program With a Pediatric Academic Medical Center.

Abstract: BACKGROUND: Pediatric airway management is a challenging process at community emergency departments (CEDs) due to lower pediatric volume, a lack of pediatric expertise among staff, and a lack of pediatric-specific equipment and resources. This has contributed to increased mortality in pediatric patients presenting to CEDs in comparison to pediatric academic medical centers (AMCs). We hypothesized that a collaborative program between CEDs and the state AMC would improve the quality of pediatric airway management provided by CEDs in simulated settings and the CEDs9 pediatric emergency readiness scores. METHODS: This prospective, pre- and post-intervention study utilized in situ simulation and was conducted in 10 CEDs in the state of Indiana. A team from the pediatric AMC led a multi-faceted improvement program, which included post-simulation debriefing, addressing pediatric airway management issues, targeted assessment reports, access to pediatric resources, and ongoing communication with the AMC. The primary outcome of the study was improvement of simulated pediatric airway management in the CEDs. The secondary outcome was improvement of the CEDs9 pediatric emergency readiness scores score. RESULTS: A total of 35 multidisciplinary teams participated in pre-intervention sessions, and 40 teams participated in post-intervention sessions. Overall adherence to a critical action checklist improved from 52% at the pre-intervention visits to 71% post-intervention (P = .003). There were significant improvements in the use of appropriate endotracheal tube (ETT) size (from 67% to 100%, P = .02), cuffed ETT (from 8% to 71%, P CONCLUSIONS: A collaborative improvement program between a pediatric AMC and CEDs improved the CEDs9 simulated pediatric emergency airway management. This model can be utilized to improve management of other pediatric critical conditions in these CEDs.

Incidence and Impact of Pulmonary Embolism During Severe COPD Exacerbation.

Abstract: BACKGROUND: Patients with COPD are at a high risk for pulmonary embolism (PE) because of systemic inflammation and co-existing comorbidities. We aimed to determine the incidence, risk factors, and impact of PE during COPD exacerbation requiring mechanical ventilation. METHODS: This prospective cohort study was conducted between March 2013 and May 2017. Subjects with severe COPD exacerbation requiring mechanical ventilation were included. A lower-limb ultrasonography or a multidetector helical computed tomography scan (MDCT) was performed according to Wells score. Subjects with ultrasonographic signs of phlebitis underwent MDCT to confirm PE. RESULTS: During the study period, 131 COPD subjects were admitted to the ICU for severe COPD exacerbation. The incidence of PE was 13.7%. Factors independently associated with PE were increased sputum volume (odds ratio [OR] = 0.106, 95% CI 0.029–0.385, P = .001), recent immobilization ≥ 7 d (OR = 5.024, 95% CI 1.470–17.170, P = .01), age ≥ 70 y (OR = 5.483, 95% CI 1.269–23.688, P = .02), and invasive mechanical ventilation at ICU admission (OR = 3.615, 95% CI 1.005–13.007, P = .049). ICU mortality was higher in the PE group (44% vs 11%). Predictive factors of mortality were PE (OR = 7.135, 95% CI 2.042–24.931, P = .002), SAPS II score at admission OR = 1.040, 95% CI 1.005–1.077, P = .02), and duration of mechanical ventilation (OR = 1.098, 95% CI 1.044–1.154, P CONCLUSIONS: PE was found to be a common etiology of severe exacerbation of COPD, leading to high mortality. Age, invasive mechanical ventilation, and immobilization were risk factors for PE.

The Impact of Delayed Diagnosis of Alpha-1 Antitrypsin Deficiency: The Association Between Diagnostic Delay and Worsened Clinical Status.

Abstract: BACKGROUND: Alpha-1 antitrypsin deficiency is frequently underrecognized. Individuals with symptoms often experience long diagnostic delays. Although a delayed diagnosis is logically presumed to be associated with adverse effects, confirmatory evidence that a delay in diagnosis confers harm is sparse. The current study characterized the association between a delayed diagnosis and the clinical status at the time of diagnosis. METHODS: Patients with newly diagnosed severe deficiency of alpha-1 antitrypsin received questionnaires that assessed self-reported diagnostic delay, the St George Respiratory Questionnaire (SGRQ) and COPD Assessment Test. Results of spirometry were retrieved and the relationship between the diagnostic delay interval and FEV1% predicted, SGRQ, and COPD Assessment Test were assessed. RESULTS: Forty subjects were recruited (31 with PI*ZZ, 9 with PI*SZ). Values for FEV1% predicted, SGRQ, and COPD Assessment Test were available for 17, 40, and 32 subjects, respectively. The relationship between the diagnostic delay interval and all outcomes was directionally consistent with an adverse impact of increasing diagnostic delay. For each additional year of diagnostic delay, the subject9s FEV1% predicted decreased by 0.3% (P = .66), The SGRQ Total score increased by 1.6 points (P CONCLUSIONS: The results of this analysis were consistent with a delayed diagnosis of alpha-1 antitrypsin deficiency being associated with worse COPD-related symptoms and functional status, and with a trend toward worsened air-flow obstruction. Given that alpha-1 antitrypsin deficiency is associated with accelerated emphysema progression, these findings underscore the importance of early detection of alpha-1 antitrypsin deficiency and reinforce guidelines that endorse alpha-1 antitrypsin deficiency testing in all adults with fixed air-flow obstruction and first-degree relatives of individuals with severe deficiency of alpha-1 antitrypsin.

PEEP Generated by High-Flow Nasal Cannula in a Pediatric Model.

Abstract: BACKGROUND: High-flow nasal cannulas (HFNC) have been increasingly used in the pediatric critical care patient population. There are different theories about the mechanism by which HFNC reduces work of breathing, including diminishing upper airway dead space by the washout of carbon dioxide. However, one of the likely primary mechanisms by which HFNC reduces work of breathing is by generating PEEP. There are limited data assessing the PEEP delivered by moderate flows (8 –50 L/min) of HFNC, which are used most commonly in pediatric patients. METHODS: Pediatric upper-airway models were created with 5 different nares produced by a 3-dimensional printer and connected to a lung simulator. Age-specific flows were delivered via the 5 different setups. Pressure throughout the simulated airway was measured at HFNC flows of 6 – 60 L/min with 25%, 50%, and 75% air leak to simulate open-mouth breathing. RESULTS: PEEPs of 1.2–36 cm H2O were generated with HFNC flows of 6 – 60 L/min. In general, for each specific cannula, increasing the flow and decreasing the air leak resulted in higher levels of PEEP delivered (P 10% difference). Changes in lung mechanics as generated by the lung simulator to simulate different patient ages resulted in the establishment of different levels of PEEP. CONCLUSIONS: HFNCs deliver varying amounts of PEEP at the alveolar level with flows of 6 – 60 L/min. Increasing flow and decreasing leak resulted in the generation of greater PEEP. PEEP levels differed across cannulas and model weights at the same leak level, likely due to differences in the nasal interface between the HFNC device and the model nares.

Physiotherapy and Weaning From Prolonged Mechanical Ventilation

Abstract: BACKGROUND: Patients undergoing prolonged mechanical ventilation represent up to 15% of all patients requiring weaning from mechanical ventilation. Although recent guidelines have recommended including physiotherapy early during mechanical ventilation to speed the process of weaning, only indirect evidence supporting the use of physiotherapy is available for patients receiving prolonged mechanical ventilation. The aim of our study was to evaluate the effects of a physiotherapy program in subjects requiring prolonged mechanical ventilation and the correlates of successful weaning. METHODS: A retrospective analysis was performed on 1,313 consecutive patients admitted to a weaning unit over a 15-y period to be liberated from prolonged mechanical ventilation. Subjects underwent a program of intensive physiotherapy organized in 4 incremental steps (1–4) and were analyzed according to the steps achieved (> 2 steps or ≤ 2 steps). The rate of successful weaning was recorded, and possible predictors were considered. The 15-y period of observation was divided into 3 consecutive 5-y intervals. RESULTS: Out of 560 subjects undergoing final analysis, 349 (62.3%) were successfully weaned. The weaning success rate was significantly greater in subjects attaining > 2 steps than in subjects who attained ≤ 2 steps (72.1% vs 55.9%, respectively, odds ratio = 2.04, 95% CI = 1.42–2.96, P 2 physiotherapy steps was the main predictor of successful weaning (odds ratio = 2.17, 95% CI = 1.48–3.23, P CONCLUSIONS: Our data support the inclusion of physiotherapy in the management of patients requiring prolonged mechanical ventilation.

Factors Influencing Activities of Daily Living in Subjects With COPD

Abstract: BACKGROUND: Activities of daily living (ADL) are important for an independent life. As COPD progresses, the ability to complete ADL is usually reduced. Knowing the possible factors that influence the ability to perform ADL may allow better targeting of appropriate rehabilitation programs to increase the independence levels and/or to prevent further decreases in patients with COPD. Therefore, the aim of this study was to investigate ADL performance as measured by the London Chest Activity of Daily Living scale, which is a commonly used measure in patients with COPD. METHODS: This cross-sectional study included 44 clinically stable subjects who were not taking antibiotics and had not made any changes in their medications for at least three weeks with a COPD diagnosis based on Global Initiative for Chronic Obstructive Lung Disease. Demographic characteristics, pulmonary function, ADL measured by the London Chest Activity of Daily Living scale, functional exercise capacity via the 6-min walk distance, disease-related symptoms measured by the COPD Assessment Test, and peripheral and respiratory muscle strength were evaluated. A multiple linear regression (stepwise) analysis was used to determine the variables that have the greatest influence on ADL (ie, the London Chest Activity of Daily Living scale score). RESULTS: The London Chest Activity of Daily Living scale score had moderate correlations with the COPD Assessment Test score (r = 0.31, P = .041), maximum expiratory pressure value (r = −0.37, P = .01), 6-min walk distance (r = −0.48, P = .001), knee extensor muscle strength (r = −0.47, P = .001), handgrip strength (r = −0.44, P = .003). The 6-min walk distance, COPD Assessment Test score and maximal expiratory pressure values were significant and independent determinants of the London Chest Activity of Daily Living scale, with 40.1% of the variance in subjects with COPD. CONCLUSIONS: Functional exercise capacity, disease-related symptoms, and expiratory muscle strength have the greatest influence on ADL in the subjects with COPD. The level of independence to perform ADL can be increased by improving functional exercise capacity, reducing symptoms, and increasing expiratory muscle strength in subjects with COPD.

Increase in Body Mass Index Decreases Duration of Apneas and Hypopneas in Obstructive Sleep Apnea

Abstract: BACKGROUND: Obesity is one of the most prominent risk factors for obstructive sleep apnea (OSA). Weight loss decreases the number of shorter respiratory events (<40 s), whereas the number of longer events remains almost unchanged. However, it is unknown how body mass index (BMI) affects individual obstruction event severity within OSA severity categories when age, sex, smoking, daytime sleepiness, snoring, hypertension, heart failure, and sleeping posture are considered. Therefore, we investigated whether individual obstruction event severity varies with BMI within the OSA severity categories when considering the most important confounding factors. METHODS: Poly-graphic recordings of 723 subjects without CPAP treatment and with an apnea-hypopnea index (AHI) of ≥5 events/hour were reanalyzed retrospectively. The effect of BMI on the severities of OSA and individual obstruction events was evaluated in general, within OSA severity categories, and between different BMI groups (ie, BMI < 25; 25 ≤ BMI < 30; 30 ≤ BMI < 35; 35 ≤ BMI < 40; and BMI ≥ 40 kg/m). RESULTS: AHI increased in mild and severe (β ≥ 0.10, P <.001) OSA categories, with increasing BMI. However, the proportion of apneas from all respiratory events decreased (β =‒0.55, P =.068) with increasing BMI in all the OSA categories. An increase in BMI led to a decrease in the median duration of individual apneas, hypopneas, and desaturations in all OSA categories, whereas desaturation depth increased statistically significantly in the severe category (β = 0.20, P <.001). CONCLUSIONS: Because BMI is related to the duration of individual obstruction events, its effect on OSA severity is more complex than its effect on AHI would implicate. Therefore, overall severity of OSA may not be the same for non-obese patient and obese patient who have similar AHI. Thus, these patient-specific characteristics of individual breathing cessations should be considered when estimating the severity of disease and risk of related adverse health effects.

Noninvasive Respiratory Support at the End of Life.

Abstract: Noninvasive respiratory support at the end of life is controversial, although it is becoming increasingly common. Supplemental oxygen is widely prescribed for palliative care and may help with hypoxemic respiratory failure. Noninvasive ventilation has a well-established evidence-based role in the management of respiratory failure due to exacerbations of COPD and cardiogenic pulmonary edema. However, its role during palliative care is unclear, and evidence of support is limited. High-flow nasal cannula oxygen therapy is a new strategy for which there is evidence to support its use for hypoxemic respiratory failure. However, any benefit of the use of high-flow nasal cannula oxygen therapy in the palliative setting is unknown at this time. This review examined evidence relating to the use of noninvasive respiratory support at the end of life.

Study of Active Duty Military Personnel for Environmental Deployment Exposures: Pre- and Post-Deployment Spirometry (STAMPEDE II)

Abstract: BACKGROUND: There is significant concern about the respiratory health of deployed military service members given the reported airborne hazards in southwest Asia, which range from geologic dusts, burn pit emissions, chemical exposures, and increased rates of smoking. There has been no previous comparison of pre- and post-deployment lung function in these individuals. METHODS: Military personnel who deployed to southwest Asia in support of ongoing military operations were recruited from the Soldier Readiness Processing Center at Fort Hood, Texas, from 2011 to 2014. The participants were asked to complete a brief survey on their respiratory health and perform both spirometry and impulse oscillometry studies at baseline with repeated survey and testing after deployment. RESULTS: Of the 1,693 deployed personnel who completed baseline examinations, 843 (50%) completed post-deployment testing. Post-deployment values demonstrated no statistical or clinical change in spirometry, with an increase in mean ± SD FEV1 (% predicted) from 95.2 ± 12.6 to 96.1 ± 12.4 (P = .14), increase in mean ± SD FVC (% predicted) from 95.9 ± 11.8 to 96.4 ± 11.9 (P = .32), and increase in mean ± SD FEV1/FVC from 81.5 ± 5.9 to 81.8 ± 6.1 (P = .29). Impulse oscillometry values showed statistical improvement with reduction in resistance (at 5 Hz and 20 Hz) and reactance (at 5 Hz). The presence of pre-deployment obstruction, self-reported asthma, smoking history, or increased body mass index also did not change spirometry values after deployment. DISCUSSION: To our knowledge, this was the first prospective evaluation of deploying military by using spirometry as an indicator for the possible development of pulmonary disease related to environmental exposures. Pre-deployment testing with spirometry and impulse oscillometry was unable to detect any significant change. In those with abnormal spirometry pre-deployment or asthma history, there was also not identifiable change that indicated worsening lung function. CONCLUSIONS: Utilization of spirometry for the deploying military population had little benefit and did not identify individuals with lung disease after deployment. Routine use was not warranted before or after deployment in the absence of pulmonary symptoms.

Mortality in Critically Ill Elderly Individuals Receiving Mechanical Ventilation.

Abstract: BACKGROUND: Previous studies that evaluated mortality in elderly subjects who received mechanical ventilation had conflicting results. The aim of this systematic review was to evaluate the effects of age on mortality. METHODS: A number of medical literature databases and the references listed (from 1974 to May 2015) were searched for studies that compared 2 different age groups. The primary outcome was mortality in subjects ages ≥ 65 y. The severity scores, ICU and hospital lengths of stay, and the presence of ventilator-associated pneumonia were secondary outcomes. Finally, mortality in the subjects with ARDS and of cutoff ages 70 and 80 y was assessed by subgroup analysis. Evidence quality was assessed by the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) criteria score. RESULTS: Of the 5,182 articles identified, 21 were included. Subjects ages ≥ 65 y had higher mortalities (odds ratio [OR] 1.80, 95% CI 1.56–2.08; I2 = 71%). APACHE (Acute Physiology and Chronic Health Evaluation) II revealed intergroup differences (mean difference 3.07, 95% CI 2.52–3.61; I2 = 0%), whereas neither the ICU nor hospital length of stay (mean difference 1.27, 95% CI −0.82 to 3.36, I2 = 82%, and mean difference 1.29, 95% CI −0.71 to 3.29, I2 = 0%, respectively) nor the groups in the 2 studies that assessed ventilator-associated pneumonia exhibited any difference. Subgroup analysis revealed a higher mortality in the older subjects, in the subjects with ARDS (OR 1.76, 95% CI 1.30–2.36; I2 = 0%) and in the subjects ages 70 and 80 y (OR 1.78, 95% CI 1.51–2.10, I2 = 71%; and OR 1.96, 95% CI 1.81–2.13, I2 = 0%, respectively). The quality of associated evidence was low or very low. CONCLUSIONS: Although low-quality evidence was available, we conclude that age is associated with a greater mortality in critical subjects who were receiving mechanical ventilation.

Exertional Desaturation and Prescription of Ambulatory Oxygen Therapy in Interstitial Lung Disease

Abstract: BACKGROUND: Exertional desaturation is an important predictor of mortality in patients with interstitial lung disease. We evaluated the prevalence of exertional desaturation in subjects with interstitial lung disease and determined its relationship with the prescription of ambulatory oxygen therapy. METHODS: Our retrospective analysis examined prospectively collected data from interstitial lung disease registries of 2 Melbourne hospitals: Alfred Health and Austin Health. All patients with baseline the 6-min walk tests on room air were included. We evaluated the prescription of ambulatory oxygen therapy, up to 3 months after 6-min walk tests, among those with exertional desaturation. RESULTS: Of the 400 subjects, 214 (54%) had exertional desaturation. The prevalence of desaturation increased with the severity of lung function impairment (FVC measurement: 33% for > 75% predicted, 69% for 50–75% predicted, 86% for 55% predicted, 64% for 36–55% predicted, 93% for ≤ 35% predicted, P CONCLUSIONS: Exertional desaturation is common in subjects with interstitial lung disease. More severely impaired exercise capacity and worse lung function are associated with the prescription of ambulatory oxygen therapy in interstitial lung disease.

Evaluation of a New Interface Combining High-Flow Nasal Cannula and CPAP.

Abstract: BACKGROUND: This study assessed the effects of a new interface that combined CPAP 10 cm H2O by using a helmet with high-flow nasal cannula (HFNC) at varying flows in healthy volunteers. Outcome measures included pharyngeal pressures, diaphragm kinetics, breathing frequency, the temperature inside the helmet, and comfort. METHODS: After baseline assessment during spontaneous breathing, HFNC was applied at flows of 30, 40, and 50 L/min. Successively, the volunteers underwent helmet CPAP at 10 cm H2O and CPAP + HFNC at flows of 30, 40, and 50 L/min. We measured the variations of pharyngeal pressures at end-expiration and end-inspiration, referenced to spontaneous breathing for HFNC and to CPAP for CPAP + HFNC, diaphragm displacement and thickness at end-expiration and thickness at end-inspiration, breathing frequency, the temperature inside the helmet, the occurrence of the fog effect, and comfort. RESULTS: Variations of pharyngeal pressures at end-inspiration changes were small overall and clinically unimportant. With the mouth closed, at increasing HFNC flow, variations of pharyngeal pressures at end-expiration increased during both HFNC (from 2.8 up to 7.7) and, to a lesser extent, CPAP + HFNC (from 2.7 up to 3.8) (P CONCLUSIONS: CPAP + HFNC was well tolerated, with no adverse effects. Based on our findings, there was no need to vary the CPAP level when adding HFNC. At least in healthy subjects, CPAP + HFNC at 30 L/min seemed to be the best combination.