Tidal Flow-Volume Loop Enveloping at Rest in Advanced COPD.

BACKGROUND: Expiratory flow limitation (EFL) is a key physiological abnormality in COPD. Comparing tidal-to-maximum flow-volume (F-V) loops is a simple and widely available method to assess EFL in patients with COPD. We aimed to investigate whether subjects with COPD showing significant resting tidal F-V enveloping (ie, > 50% tidal volume) would present with higher exertional operating lung volumes, which would lead to greater burden of dyspnea and poorer exercise tolerance compared to their counterparts. METHODS: 37 subjects with COPD (21 males; 63.1 ± 9.2 years old; FEV1 = 37 ± 12% predicted) and 9 paired controls (3 males; 55.9 ± 11.7 y old) performed an incremental cardiopulmonary exercise testing on a cycle ergometer. Dyspnea perception, inspiratory capacity maneuvers after 3-4 sequential tidal F-V loops, and esophageal and gastric pressures were measured during exercise. RESULTS: Most subjects (31 of 37, 84%) presented with significant tidal F-V enveloping. Critical inspiratory constraints and upward dyspnea inflection points (as a function of both work rate and ventilation) were reached earlier in these subjects, thereby leading to poorer exercise tolerance compared to their counterparts (P = .01). Abdominal muscle recruitment (ie, increase in gastric pressure ≥ 15%) during tidal expiration was significantly higher in the EFL+ group. However, this did not bear an influence on the operating lung volumes, inspiratory constraints, dyspnea, cardiocirculatory responses, or exercise tolerance (P > .05). CONCLUSIONS: Tidal F-V loop enveloping at rest should be valued as it is related to relevant clinical outcomes, such as dyspnea burden and exercise tolerance in subjects with COPD.

Low exertional inspiratory capacity is not related to dynamic inspiratory muscle weakness in heart failure.

Reduction in inspiratory capacity (IC) during exercise has been reported in chronic heart failure (CHF). Since inspiratory muscle dysfunction may be present to a variable degree, the assumption that IC reduction during exercise represents an increase in end-expiratory lung volume must be made with caution. This interpretation is flawed if patients develop dynamic inspiratory muscle strength reduction, i.e., progressively lower esophageal (Pes) pressures as the IC maneuvers are repeated. Sixteen CHF patients and 9 age-matched controls performed an incremental exercise test with serial IC and respiratory pressure measurements. Regardless whether IC decreased or not with exercise (N = 4 and N = 12, respectively), Pes,IC remained stable. This was confirmed by similar Pes,sniff immediately upon exercise cessation (p > .05). No association was found between changes in IC and related Pes from rest to peak exercise. Owing to the lack of dynamic inspiratory muscle weakness, non-invasive indexes of lung mechanics can be reliably obtained from exercise IC in CHF.

Effectiveness assessment of a guideline based protocol for ventilatory support management of COPD exacerbations in an emergency department.

OBJECTIVES: To investigate clinical outcomes according to ventilatory support indication in subjects with chronic obstructive pulmonary disease exacerbation in a "real-life" Emergency Department and to analyze potential predictors of successful noninvasive positive pressure ventilation. METHODS: Retrospective cohort performed over an 18-month period, comparing the following patient groups with chronic obstructive pulmonary disease exacerbation: Group A composed of patients initially selected to receive noninvasive positive pressure ventilation without the subsequent need for invasive mechanical ventilation (successful-noninvasive positive pressure ventilation); Group B composed of patients transitioning from noninvasive positive pressure ventilation to invasive mechanical ventilation (failed-noninvasive positive pressure ventilation); and Group C composed of patients who presented with immediate need for invasive mechanical ventilation (without prior noninvasive positive pressure ventilation). RESULTS: 117 consecutive chronic obstructive pulmonary disease exacerbation admissions (Group A=96; Group B=13; Group C=8) of candidates for ventilatory support were reviewed. No differences in baseline disease severity and physiological parameters were found between the groups at Emergency Department admission. Nevertheless, Group B had higher intensive care unit admission, length of hospital stay, length of intensive care unit stay, and higher in-hospital mortality compared to Group A. Group C also had worse outcomes when compared to Group A. The only independent variable associated with the successful use of noninvasive positive pressure ventilation were improvement in arterial carbon dioxide pressure after 1h of noninvasive positive pressure ventilation use and its tolerance. CONCLUSION: Our data confirmed in a "real life" Emergency Department cohort that successful management of chronic obstructive pulmonary disease exacerbation with noninvasive positive pressure ventilation showed lower in-hospital mortality and Intensive Care Unit stay when compared to patients transitioning from noninvasive positive pressure ventilation to invasive mechanical ventilation or patients who presented an immediate need for invasive mechanical ventilation. noninvasive positive pressure ventilation tolerance and higher arterial carbon dioxide pressure reduction after 1-h of noninvasive positive pressure ventilation were predictors of successful treatment. These results should be confirmed in a prospective randomized controlled trial.

Clinical findings of speech therapy swallowing assessments in patients with oropharyngeal dysphagia following orotracheal intubation

Introduction: Endotracheal intubation has been associated with oropharyngeal dysphagia. The aim of this study was to identify the prevalence of oropharyngeal dysphagia among patients in an intensive care unit (ICU) by comparing patients requiring orotracheal intubation with those who did not undergo this procedure. Methods: This is a cross-sectional study that analyzed the medical records of 681 patients admitted to the ICU of Hospital de Clínicas de Porto Alegre between 2014 and 2017; inclusion criteria were patients aged 18 years and older who had been assessed by the hospital's Speech Therapy Service. Patients who had undergone tracheostomy, who had incomplete medical records or multiple speech-language assessments were excluded. Results: A total of 380 patients were included in the statistical analysis: 97 (25.5%) had not undergone orotracheal intubation (Group 1), 229 (60.3%) had undergone orotracheal intubation once (Group 2), and 54 (14.2%) had undergone orotracheal intubation on 2 or more occasions (Group 3). Regarding the Functional Oral Intake Scale (FOIS), 61.1% of patients in Group 3 received a FOIS I classification (p = 0.020), whereas 16.5% of patients from Group 1 received a FOIS V. Concerning their outcomes, 40.7% of patients in Group 3 died (p = 0.006), and 82.5% of patients in Group 1 were discharged from the ICU. Considering the severity of oropharyngeal dysphagia according to the Dysphagia Risk Evaluation Protocol (PARD), no statistically significant association was observed between groups (p = 0.261). Conclusions: In this study, the prevalence of oropharyngeal dysphagia was higherin patients who had undergone orotracheal intubation in the ICU. (AU)

High-flow nasal cannula oxygen therapy in acute respiratory failure due to acute exacerbation of fibrotic interstitial lung disease

High flow nasal cannula oxygen therapy (HFNC) has become frequent in the treatment of patients with acute hypoxemic respiratory failure. Methods. Eleven patients with acute exacerbation of fibrotic interstitial lung disease (ILD) were treated with HFNC after failure of conventional therapy (SatO2 < 90% offering 100% FiO2 by non-rebreathing mask or noninvasive ventilation). Ten patients had success with HFNC (not requiring orotracheal intubation) during emergency department admission. HFNC significantly improves clinical variables after 2h: respiratory rate decreased from 33 ± 6 breaths/ min to 23 ± 3 breaths/min; PaO2 increased from 48.7 (38-59) mmHg to 81.1 (76-90) mmHg; PaO2/FiO2 ratio increased from 102.4 ± 32.2 to 136.6 ± 29.4; SatO2 increased from 85 (66-92)% to 96 ± (95-97)%. HFNC could be an effective alternative in the treatment of acute respiratory failure from acute exacerbations of fibrotic ILD.(AU)

Effects of diaphragmatic contraction on lower limb venous return and central hemodynamic parameters contrasting healthy subjects versus heart failure patients at rest and during exercise.

The main objective was to assess the effects of abdominal breathing (AB) versus subject's own breathing on femoral venous blood flow (Qfv) and their repercussions on central hemodynamics at rest and during exercise contrasting healthy subjects versus heart failure (HF) patients. We measured esophageal and gastric pressure (PGA), Qfv and parameters of central hemodynamics in eight healthy subjects and nine HF patients, under four conditions: subject's own breathing and AB ( ∆: PGA ≥ 6 cmH2O) at rest and during knee extension exercises (15% of 1 repetition maximum) until exhaustion. Qfv and parameters of central hemodynamics [stroke volume (SV), cardiac output (CO)] were measured using Doppler ultrasound and impedance cardiography, respectively. At rest, healthy subjects Qfv, SV, and CO were higher during AB than subject's breathing (0.11 ± 0.02 vs. 0.06 ± 0.00 L·min(-1), 58.7 ± 3.4 vs. 50.1 ± 4.1 mL and 4.4 ± 0.2 vs. 3.8 ± 0.1 L·min(-1), respectively, P ≤ 0.05). ∆SV correlated with ∆PGA during AB (r = 0.89, P ≤ 0.05). This same pattern of findings induced by AB was observed during exercise (SV: 71.1 ± 4.1 vs. 65.5 ± 4.1 mL and CO: 6.3 ± 0.4 vs. 5.2 ± 0.4 L·min(-1); P ≤ 0.05); however, Qfv did not reach statistical significance. The HF group tended to increase their Qfv during AB (0.09 ± 0.01 vs. 0.07 ± 0.03 L·min(-1), P = 0.09). On the other hand, unlike the healthy subjects, AB did not improve SV or CO neither at rest nor during exercise (P > 0.05). In healthy subjects, abdominal pump modulated venous return improved SV and CO at rest and during exercise. In HF patients, with elevated right atrial and vena caval system pressures, these findings were not observed.

Inspiratory muscle training in type 2 diabetes with inspiratory muscle weakness.

PURPOSE: Patients with type 2 diabetes mellitus may present weakness of the inspiratory muscles. We tested the hypothesis that inspiratory muscle training (IMT) could improve inspiratory muscle strength, pulmonary function, functional capacity, and autonomic modulation in patients with type 2 diabetes and weakness of the inspiratory muscles. METHODS: Maximal inspiratory muscle pressure (PImax) was evaluated in a sample of 148 patients with type 2 diabetes. Of these, 25 patients with PImax<70% of predicted were randomized to an 8-wk program of IMT (n=12) or placebo-IMT (n=13). PImax, inspiratory muscle endurance time, pulmonary function, peak oxygen uptake, and HR variability were evaluated before and after intervention. RESULTS: The prevalence of inspiratory muscle weakness was 29%. IMT significantly increased the PImax (118%) and the inspiratory muscle endurance time (495%), with no changes in pulmonary function, functional capacity, or autonomic modulation. There were no significant changes with placebo-IMT. CONCLUSIONS: Patients with type 2 diabetes may frequently present inspiratory muscle weakness. In these patients, IMT improves inspiratory muscle function with no consequences in functional capacity or autonomic modulation.