Development of clinical tools to estimate the breathing effort during high-flow oxygen therapy: A multicenter cohort study

INTRODUCTION AND OBJECTIVES

Quantifying breathing effort in non-intubated patients is important but difficult. We aimed to develop two models to estimate it in patients treated with high-flow oxygen therapy.

PATIENTS AND METHODS

We analyzed the data of 260 patients from previous studies who received high-flow oxygen therapy. Their breathing effort was measured as the maximal deflection of esophageal pressure (ΔPes). We developed a multivariable linear regression model to estimate ΔPes (in cmH2O) and a multivariable logistic regression model to predict the risk of ΔPes being >10 cmH2O. Candidate predictors included age, sex, diagnosis of the coronavirus disease 2019 (COVID-19), respiratory rate, heart rate, mean arterial pressure, the results of arterial blood gas analysis, including base excess concentration (BEa) and the ratio of arterial tension to the inspiratory fraction of oxygen (PaO2:FiO2), and the product term between COVID-19 and PaO2:FiO2.

RESULTS

We found that ΔPes can be estimated from the presence or absence of COVID-19, BEa, respiratory rate, PaO2:FiO2, and the product term between COVID-19 and PaO2:FiO2. The adjusted R2 was 0.39. The risk of ΔPes being >10 cmH2O can be predicted from BEa, respiratory rate, and PaO2:FiO2. The area under the receiver operating characteristic curve was 0.79 (0.73-0.85). We called these two models BREF, where BREF stands for BReathing EFfort and the three common predictors: BEa (B), respiratory rate (RE), and PaO2:FiO2 (F).

CONCLUSIONS

We developed two models to estimate the breathing effort of patients on high-flow oxygen therapy. Our initial findings are promising and suggest that these models merit further evaluation.

Association between respiratory distress time and invasive mechanical ventilation in COVID-19 patients: A multicentre regional cohort study

AIM

To determine whether the duration of respiratory distress symptoms in severe COVID-19 pneumonia affects the need for invasive mechanical ventilation and clinical outcomes.

MATERIALS AND METHODS

An observational multicentre cohort study of patients hospitalised in five COVID-19-designated ICUs of the University Hospitals of Emilia-Romagna Region. Patients included were adults with pneumonia due to SARS-CoV-2 with PaO₂/FiO₂ ratio <300 mmHg, respiratory distress symptoms, and need for mechanical ventilation (invasive or non-invasive). Exclusion criteria were an uncertain time of respiratory distress, end-of-life decision, and mechanical respiratory support before hospital admission.

MEASUREMENTS AND MAIN RESULTS

We analysed 171 patients stratified into tertiles according to respiratory distress duration (distress time, DT) before application of mechanical ventilation support. The rate of patients requiring invasive mechanical ventilation was significantly different (p < 0.001) among the tertiles: 17/57 patients in the shortest duration, 29/57 in the intermediate duration, and 40/57 in the longest duration. The respiratory distress time significantly increased the risk of invasive ventilation in the univariate analysis (OR 5.5 [CI 2.48-12.35], p = 0.003). Multivariable regression analysis confirmed this association (OR 10.7 [CI 2.89-39.41], p < 0.001). Clinical outcomes (mortality and hospital stay) did not show significant differences between DT tertiles.

DISCUSSION

Albeit preliminary and retrospective, our data raised the hypothesis that the duration of respiratory distress symptoms may play a role in COVID-19 patients' need for invasive mechanical ventilation. Furthermore, our observations suggested that specific strategies may be directed towards identifying and managing early symptoms of respiratory distress, regardless of the levels of hypoxemia and the severity of the dyspnoea itself.

Inspiratory Effort and Respiratory Mechanics in Patients with Acute Exacerbation of Idiopathic Pulmonary fibrosis: A Preliminary Matched Control Study

BACKGROUND

Patients with acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) may experience severe acute respiratory failure, even requiring ventilatory assistance. Physiological data on lung mechanics during these events are lacking.

METHODS

Patients with AE-IPF admitted to Respiratory Intensive Care Unit to receive non-invasive ventilation (NIV) were retrospectively analyzed. Esophageal pressure swing (ΔPes) and respiratory mechanics before and after 2 hours of NIV were collected as primary outcome. The correlation between positive end-expiratory pressure (PEEP) levels and changes of in dynamic compliance (dynCRS) and PaO2/FiO2 ratio was assessed. Further, an exploratory comparison with a historical cohort of ARDS patients matched 1:1 by age, sequential organ failure assessment score, body mass index and PaO2/FiO2 level was performed.

RESULTS

At baseline, AE-IPF patients presented a high respiratory drive activation with ΔPes = 27 (21-34) cmH2O, respiratory rate (RR) = 34 (30-39) bpm and minute ventilation (VE) = 21 (20-26) L/min. Two hours after NIV application, ΔPes, RR and VE values showed a significant reduction (16 [14-24] cmH2O, p<0.0001, 27 [25-30] bpm, p=0.001, and 18 [17-20] L/min, p=0.003, respectively) while no significant change was found in dynamic transpulmonary pressure, expiratory tidal volume (Vte), dynCRS and dynamic mechanical power. PEEP levels negatively correlated with PaO2/FiO2 ratio and dynCRS (r=-0.67, p=0.03 and r=-0.27, p=0.4, respectively). When compared to AE-IPF, ARDS patients presented lower baseline ΔPes, RR, VE and dynamic mechanical power. Differently from AE-IPF, in ARDS both Vte and dynCRS increased significantly following NIV (p=0.01 and p=0.004 respectively) with PEEP levels directly associated with PaO2/FiO2 ratio and dynCRS (r=0.24, p=0.5 and r=0.65, p=0.04, respectively).

CONCLUSIONS

In this study, patients with AE-IPF showed a high inspiratory effort, whose intensity was reduced by NIV application without a significant improvement in respiratory mechanics. In an exploratory analysis, AE-IPF patients showed a different mechanical behavior under spontaneous unassisted and assisted breathing compared with ARDS patients of similar severity.

COPD: Providing the right treatment for the right patient at the right time

Chronic Obstructive Pulmonary Disease (COPD) is a common disease associated with significant morbidity and mortality that is both preventable and treatable. However, a major challenge in recognizing, preventing, and treating COPD is understanding its complexity. While COPD has historically been characterized as a disease defined by airflow limitation, we now understand it as a multi-component disease with many clinical phenotypes, systemic manifestations, and associated co-morbidities. Evidence is rapidly emerging in our understanding of the many factors that contribute to the pathogenesis of COPD and the identification of "early" or "pre-COPD" which should provide exciting opportunities for early treatment and disease modification. In addition to breakthroughs in our understanding of the origins of COPD, we are optimizing treatment strategies and delivery of care that are showing impressive benefits in patient-centered outcomes and healthcare utilization. This special issue of Respiratory Medicine, "COPD: Providing the Right Treatment for the Right Patient at the Right Time" is a summary of the proceedings of a conference held in Stresa, Italy in April 2022 that brought together international experts to discuss emerging evidence in COPD and Pulmonary Rehabilitation in honor of a distinguished friend and colleague, Claudio Ferdinando Donor (1948-2021). Claudio was a true pioneer in the field of pulmonary rehabilitation and the comprehensive care of individuals with COPD. He held numerous leadership roles in in the field, provide editorial stewardship of several respiratory journals, authored numerous papers, statement and guidelines in COPD and Pulmonary Rehabilitation, and provided mentorship to many in our field. Claudio's most impressive talent was his ability to organize spectacular conferences and symposia that highlighted cutting edge science and clinical medicine. It is in this spirit that this conference was conceived and planned. These proceedings are divided into 4 sections which highlight crucial areas in the field of COPD: (1) New concepts in COPD pathogenesis; (2) Enhancing outcomes in COPD; (3) Non-pharmacologic management of COPD; and (4) Optimizing delivery of care for COPD. These presentations summarize the newest evidence in the field and capture lively discussion on the exciting future of treating this prevalent and impactful disease. We thank each of the authors for their participation and applaud their efforts toward pushing the envelope in our understanding of COPD and optimizing care for these patients. We believe that this edition is a most fitting tribute to a dear colleague and friend and will prove useful to students, clinicians, and researchers as they continually strive to provide the right treatment for the right patient at the right time. It has been our pleasure and a distinct honor to serve as editors and oversee such wonderful scholarly work.

Sub-clinical left ventricular diastolic dysfunction in early stage of chronic obstructive pulmonary disease

Sub-clinical cardiac dysfunction may be significantly associated with chronic obstructive pulmonary disease (COPD) with a different degree of severity. In a cross-sectional design we aimed to evaluate the frequency of left ventricular diastolic dysfunction (LVdd) and its correlation with lung function, pulmonary arterial pressure and systemic inflammation in a selected population of COPD at an early stage of their disease. Fifty-five COPD patients with no clinical signs of cardiovascular dysfunction were recruited and compared to 40 matched healthy controls. All the subjects underwent pulmonary function testing, doppler echocardiography, and interleukin-6 blood sampling. Presence of LVdd was defined according to the significant change in both the ratio between early and late diastolic transmitral flow velocity (E/A ratio), isovolumetric relaxation time (IVRT), and deceleration time (DT). The frequency of LVdd was higher in the COPD group (70.9 percent) compared to controls (27.5 percent). In these patients decreased E/A ratio, and prolonged IVRT and DT clearly pointed to left ventricular filling impairment, a condition we found to be especially severe in those patients suffering from lung static hyperinflation as expressed by inspiratory-to-total lung capacity ratio (IC/TLC) <0.25. Circulating levels of interleukin-6 were also higher among COPD patients compared to controls. The results of the present study suggest that subclinical left ventricular filling impairment is frequently found in COPD patients at the earlier stage of the disease even in the absence of any other cardiovascular dysfunction. Doppler echocardiography may help the early identification of LVdd in COPD patients.

Selected clinical highlights from the 2010 ERS Congress in Barcelona

This article reviews a selection of presentations at the 2010 annual meeting of the European Respiratory Society held in Barcelona, Spain, which was the largest congress ever in the field of respiratory medicine. The best abstracts from the groups of the Clinical Assembly (Clinical Problems, Rehabilitation and Chronic Care, Imaging, Interventional Pulmonology, Diffuse Parenchymal Lung Disease, and General Practice and Primary Care) are presented in the context of the current literature.

Interdisciplinary rehabilitation in morbidly obese subjects: an observational pilot study

BACKGROUND AND AIM

To assess the clinical effectiveness of a interdisciplinary rehabilitation programme (CR), in a population of morbidly obese subjects we have undertaken a observational study.

METHODS

The study included fifty-nine adult subjects (18 M, 60+/-10 years, BMI 47+/-8) with sleep-disturbance related symptoms and disabilities. Assessment and correction of sleep disordered breathing (SDB) abnormalities, improvement of exercise tolerance, body weight and associated psychological features were the aims of this CR, which has been carried out over a 1 month period. Lung functions, apnea/hypopnea index (AHI), 6-minute walking distance (6MWD), body weight (BW), quality of life by means of Sat-P questionnaire and serum metabolic data has been recorded at baseline (TO), at the end (Ti) and 6 months after (T2) the CR.

RESULTS

The percentage of patients with AHI > 10 declined from 65% (at TO) to 20% (at both T1 and T2). 6MWD and BW significantly improved (p < 0.005) at T1 and still maintained at T2; a significant relationship (r = 0.379, p < 0.01) has been found between changes of BW and 6MWD recorded in between TO and T2. Sat-P item scores dealing with sleep efficiency, problem solving, and social interactions improved (p < 0.01) at T1 and still maintained at T2.

CONCLUSIONS

This hospital-based CR provides indication for effectiveness in advanced morbidly obese subjects and warrants further controlled trials to confirm the results.

Maximal inspiratory and expiratory pressure measurement in tracheotomised patients

The present study compared four different sites and conditions for the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) in 38 spontaneous breathing tracheotomised patients. Of the patients, 28 had chronic obstructive pulmonary disease (COPD). The four different conditions were: 1) through a cuff inflated cannula (condition A); 2) through the mouth with a deflated cannula (condition B); 3) through the mouth with a phonetic uncuffed cannula (condition C); and 4) through the mouth after stoma closure (condition D). Five trials in each condition were performed using a standardised method. The measurement of both MIP and MEP differed significantly depending on the condition of measurement. MIP taken in condition A was significantly higher when compared with conditions B, C and D. MEP in condition A was significantly higher when compared with condition B and D. In condition A the highest frequency of the best measurement of MIP and MEP was observed at the fourth and fifth effort, respectively. The same results were obtained after the selection of only COPD patients. In conclusion, respiratory muscle assessment differs significantly depending on measurement condition. Measurement through inflated cannula tracheotomy yields higher values of both maximal inspiratory and maximal expiratory pressure.

Inspiratory muscle workload due to dynamic intrinsic PEEP in stable COPD patients: effects of two different settings of non-invasive pressure-support ventilation

BACKGROUND

In severe stable hypercapnic COPD patients the amount of pressure time product (PTP) spent to counterbalance their dynamic intrinsic positive end expiratory pressure (PEEPi,dyn) is high: no data are available on the best setting of non invasive pressure support ventilation (NPSV) to reduce the inspiratory muscle workload due to PEEPi,dyn.

METHODS

The objectives of this randomised controlled physiological study were: 1. To measure the inspiratory muscle workload due to PEEPi,dyn 2. To measure the effects on this parameter of two settings of NPSV in stable COPD patients with chronic hypercapnia admitted in a Pulmonary Division of two Rehabilitation Centers. Twenty-three stable COPD patients with chronic hypercapnia on domiciliary nocturnal NPSV for 30 +/- 20 months were submitted to an evaluation of breathing pattern, PEEPi,dyn, inspiratory muscle workload and its partitioning during both assisted and unassisted ventilation. Two settings of NPSV were randomly applied for 30 minutes each: i- "at patient's comfort" (C): Inspiratory pressure support (IPS) was the maximal tolerated pressure able to reduce awake PaCO2 with the addition of a pre-set level of external PEEP (PEEPe); ii- "physiological setting" (PH): the level of IPS able to achieve a > 40% and < 90% decrease in transdiaphragmatic pressure in comparison to spontaneous breathing (SB). A PEEPe level able to reduce PEEPi,dyn by at least 50% was added.

RESULTS

During SB the tidal diaphragmatic pressure-time product (PTPdi/b) was 17.62 +/- 7.22 cmH2O*sec, the component due to PEEPi,dyn (PTPdiPEEPi,dyn) being 38 +/- 17% (range: 16-65%). Compared to SB,PTPdiPEEPi,dyn was reduced significantly with both settings, the reduction being greater with PH compared to C.

CONCLUSIONS

In conclusion in severe COPD patients with chronic hypercapnia the inspiratory muscle workload due to PEEPidyn is high and is reduced by NPSV at a greater extent when ventilator setting is tailored to patient's mechanics.

Rehabilitation of COPD patients: which training modality

Non pharmacological therapy has been gaining more interest and has been evolving rapidly over the last decade as an essential part of therapy for COPD patients. Pulmonary Rehabilitation (PR), the most important non pharmacological treatment in patients with COPD, has a primary goal: to achieve the highest possible level of individual exercise tolerance, thus reducing the primary and/or secondary health care utilisation. The aim of the present review is to focus the role of exercise training in these patients as well as to address the question on which training methods are the most beneficial. We have therefore undertaken a MEDLINE-based search including the terms: pulmonary rehabilitation, exercise, lung disease/obstructive. Several strategies based on endurance or strength training are nowadays implemented during PR programmes in order to maximise the benefits for each patient. The impaired function of ambulation muscles causing breathlessness as one of the more frequent symptoms in many COPD, suggests that training the lower extremities is the most important goal to achieve during pulmonary rehabilitation of these patients. On the other hand, as muscle strength appears to be an independent contributor to survival and utilisation of health care resources, it seems largely justified also to include this further modality in the PR program of these patients. In conclusion, both modalities are effective and useful for COPD patients. However, whether resistance training should be administered to all COPD and which is the optimal length of strength training still needs to be elucidated.

Hospital monitoring, setting and training for home non invasive ventilation

Although in recent years guidelines have been published in order to define indications, applications and delivery of long-term home non invasive mechanical ventilation (HNMV), there is lack of information with regards to in-hospital assessment, planning and training to initiate and prescribe it. Discontinuation and lack of compliance versus HNMV may affect the follow-up of these patients adding a costly burden for care. The present review proposes an operative flow chart for optimisation of HNMV prescription from initial patient's selection to post discharge follow up including; 1. assessment of the correct choice of ventilator, interfaces, ventilation setting. 2. Timing for different physiological monitoring (arterial gases, mechanics, sleep) 3. Timing for clinical evaluation, machine adaptation, carer training and long term follow-up.

Impact of comprehensive pulmonary rehabilitation on anxiety and depression in hospitalized COPD patients

To prospectively evaluate the effect of inpatient pulmonary rehabilitation (iPR) on anxiety and depression as outcome measures in patients with COPD, we studied 149 consecutive adults COPD referred to our iPR after an exacerbation. Patients were divided according to the GOLD staging into: Group 1 (stage 2a, n = 48, FEV1 63 +/- 9% pred.), Group 2 (stage 2b, n = 53, FEV1 42 +/- 6% pred.) and Group 3 (stage 3, n = 48, FEV1 25 +/- 7% pred.). The iPR consisted of twelve 3-hours daily sessions. Hospital Anxiety Depression (HAD) Scale as well as 6-minute walk (6MWD) with evaluation of dyspnea (D) and leg fatigue (F) at rest and end of effort, and health related quality of life by means of St. George Respiratory Questionnaire (SGRQ) were assessed before (T0) and after (T1) the iPR. 6MWD, D and F at end of effort and SGRQ total score similarly improved (p < 0.001) in all groups after iPR. The mean level of HAD-anxiety (from 9.1 +/- 4.0 to 7.7 +/- 3.5, from 9.0 +/- 4.6 to 7.2 +/- 4.6 and from 8.1 +/- 4.1 to 6.7 +/- 4.3 in group 1,2 and 3 respectively) and HAD-depression (from 9.4 +/- 3.5 to 8.2 +/- 3.5, from 9.1 +/- 4.2 to 8.2 +/- 4.5 and from 9.0 +/- 4.0 to 7.4 +/- 4.5 respectively) similarly changed (p < 0.0001) over time in all groups. The total percentage of patients with abnormal score (> 10) of HAD-anxiety (from 31% to 21%) and HAD-depression (from 30% to 22%) significantly decreased (p < 0.05) after the iPR. Inpatient pulmonary rehabilitation may improve levels of anxiety and depression as well as symptoms, exercise capacity and health related quality of life in moderate to severe COPD patients after an acute exacerbation.

The Italian multicentre study on noninvasive ventilation in chronic obstructive pulmonary disease patients

Chronic obstructive pulmonary disease (COPD) patients with chronic ventilatory failure (CVF) are more likely to develop exacerbations, which are an important determinant of health-related quality of life (HRQL). Long-term noninvasive positive-pressure ventilation (NPPV) has been proposed in addition to long-term oxygen therapy (LTOT) to treat CVF but little information is available on its effects on HRQL and resource consumption. Therefore, the current authors undertook a 2-yr multicentric, prospective, randomised, controlled trial to assess the effect of NPPV+ LTOT on: 1) severity of hypercapnia; 2) use of healthcare resources, and 3) HRQL, in comparison with LTOT alone. One hundred and twenty-two stable hypercapnic COPD patients on LTOT for > or = 6 months were consecutively enrolled. After inclusion and 1-month run-in, 90 patients were randomly assigned to NPPV+LTOT (n=43) or to LTOT alone (n=47). Arterial blood gases, hospital and intensive care unit (ICU) admissions, total hospital and ICU length of stay and HRQL were primary outcome measures; survival and drop-out rates, symptoms (dyspnoea and sleep quality) and exercise tolerance were secondary outcome measures. Follow-up was performed at 3-month intervals up to 2 yrs. Lung function, inspiratory muscle function, exercise tolerance and sleep quality score did not change over time in either group. By contrast the carbon dioxide tension in arterial blood on usual oxygen, resting dyspnoea and HRQL, as assessed by the Maugeri Foundation Respiratory Failure Questionnaire, changed differently over time in the two groups in favour of NPPV+LTOT. Hospital admissions were not different between groups during the follow-up. Nevertheless, overall hospital admissions showed a different trend to change in the NPPV+LTOT (decreasing by 45%) as compared with the LTOT group (increasing by 27%) when comparing the follow-up with the follow-back periods. ICU stay decreased over time by 75% and 20% in the NPPV+LTOT and LTOT groups, respectively. Survival was similar. Compared with long-term oxygen therapy alone, the addition of noninvasive positive-pressure ventilation to long-term oxygen therapy in stable chronic obstructive pulmonary disease patients with chronic ventilatory failure: 1) slightly decreased the trend to carbon dioxide retention in patients receiving oxygen at home and 2) improved dyspnoea and health-related quality of life. The results of this study show some significant benefits with the use of nocturnal, home noninvasive positive-pressure ventilation in patients with chronic ventilatory failure due to advanced chronic obstructive pulmonary disease patients. Further work is required to evaluate the effect of noninvasive positive-pressure ventilation on reducing the frequency and severity of chronic obstructive pulmonary disease exacerbation.

Exhaled nitric oxide and exercise tolerance in severe COPD patients

To answer the question as to whether pulmonary rehabilitation programs (PRP) induced increase in exercise tolerance (ET) is associated with increased levels of exhaled nitric oxide (eNO) in COPD patients of different degrees of severity, we designed a prospective and controlled study. Forty-seven stable COPD patients underwent an 8-week outpatient multidisciplinary PRP including supervised incremental exercise. Fractional eNO concentration (FE(NO)) and peak work-rate (W(peak) were assessed baseline (T-1), atthe end of 1-month run-in period (T0), and after (T1) the PRP. Lung function, walking test, health-related quality of life (HRQL) were also recorded. Patients were divided into three groups according to disease severity: 17 severe [FEV1 35 (5)% pred] COPD patients, seven of them with cor pulmonale; 15 mild [FEV1 78 (6)% pred], and 15 moderate [FEV1 56 (6)% pred] COPD patients. FE(NO) did not differ at T-1 and T0 (mean absolute change (SD): 0.03 (0.09) 95% CI-0.01, 0.16, 0.06 (1.03) 95% CI 0.03, 0.75 and 0.05 (0.06) 95% CI 0.02, 0.11 ppb in mild, moderate and severe patients, respectively). As compared to T0, both W(peak) (by 17,15 and 10%, respectively) and FE(NO) (by 29, 24 and 16%, respectively) significantly increased in all groups, but not in patients with cor pulmonale. A significant correlation between pre- and post-PRP changes in Wpeak and FE(NO) was found both in mild to moderate (r = 0.79, P < 0.00001) and severe (r = 0.76, P < 0.001) COPD patients. After a PRP, improvement in ET is associated with an increase in eNO also in most severe COPD patients, but not in those with cor pulmonale.

One-year mortality in elderly stable patients with COPD

A retrospective study was performed to evaluate the risks of one-year mortality in very old hospitalized patients including those suffering from chronic obstructive pulmonary disease (COPD). Six hundred and fifty-eight disabled patients (M = 194, mean age 79.2 +/- 7.4 years) consecutively admitted to and discharged from a Geriatric Evaluation and Rehabilitation Unit (GERU) after a comprehensive rehabilitation program were studied and divided into two groups: COPD (n = 337, 51%) and non-COPD (n = 321, 49%). Multidimensional evaluation including information on demographics, cognitive status [Mini Mental State Examination (MMSE)], physical health [number of diseases, Greenfield's Individual Disease Severity (IDS), and number of drugs used], functional disability [Basic Activity of Daily Living (BADL), Tinetti scale, and Physical Performance Test (PPT)], and nutritional status [Prognostic Nutritional Index (PNI)] were assessed at admission. Survival rate was assessed over a 1-year period following discharge. COPD patients mainly differed from non-COPD in terms of older age, smoking habit, number of associated diseases and drugs used. Aggregating the IDS 2-3-4 COPD classes (symptoms + functional impairment), the risk of one-year mortality was double that of the IDS 1 COPD class (symptoms only) and of non-COPD subjects (IDS 0 class) after adjusting for age, sex, disability, malnutrition, and comorbility. Moreover, IDS 2-3-4 COPD patients suffering from cor pulmonale (CP) had a fourfold 1-year risk of mortality in comparison with the IDS 1 COPD group after adjusting for the same covariates. Hospitalized stable very old COPD patients presenting functional impairment have a higher 1-year risk of mortality than only symptomatic COPD or non-COPD subjects. The presence of cor pulmonale with COPD further increases this risk.

In-hospital short-term training program for patients with chronic airway obstruction

OBJECTIVE

To compare the functional benefits and relative costs of administering an intense short-term inpatient vs a longer outpatient pulmonary rehabilitation program (PRP) for patients with chronic airway obstruction (CAO).

DESIGN

Retrospective case-control study.

SETTING

Pulmonary ward and outpatient clinic of a rehabilitation center.

PATIENTS

Forty-three patients (case subjects) selected on the basis of selection criteria were compared with control subjects matched to them for age, sex, FEV(1), and diagnosis of either COPD or asthma. Case subjects performed 10 to 12 daily sessions (5 sessions a week) of inpatient PRP; control subjects performed 20 to 24 sessions (3 sessions a week) of outpatient PRP.

MEASUREMENTS

At baseline and after the PRP, an incremental exercise test was performed, including evaluation of dyspnea and leg fatigue by Borg scale (D and F, respectively) at each workload step. The cost of PRP was also evaluated.

RESULTS

Both PRPs resulted in similar significant improvements in cycloergometry peak workload (from 68 +/- 18 to 82 +/- 22 and from 75 +/- 17 to 87 +/- 27 W in case subjects and control subjects, respectively), isoload D (from 6.4 +/- 1.6 to 4.2 +/- 1.8 for case subjects and from 8.5 +/- 1.9 to 6.3 +/- 2.4 for control subjects) and isoload F (from 6.6 +/- 1.8 to 4.2 +/- 1.8 for case subjects and from 8.9 +/- 1.9 to 7.0 +/- 1.8 for control subjects). Although the single daily session was less expensive, the outpatient PRP total costs were greater because of the higher number of sessions and the cost of daily transportation.

CONCLUSIONS

In patients with CAO, a shorter inpatient PRP may result in improvement in exercise tolerance similar to a longer outpatient PRP but with lower costs. Whether a shorter outpatient PRP may get physiologic and clinical benefits, while further reducing costs, must be evaluated by future controlled, randomized, prospective studies.

Physiological response to pressure support ventilation delivered before and after extubation in patients not capable of totally spontaneous autonomous breathing

We designed a prospective, physiological study in 12 patients affected by chronic respiratory disorders. The study was aimed at assessing the diaphragm energy expenditure (PTPdi), lung resistance (RL) and elastance (EL), arterial blood gases (ABG), breathing pattern, and dyspnea measured by a visual analog scale during invasive pressure support ventilation (i-PSV) and noninvasive PSV (n-PSV). The ventilator settings were kept the same. Both i-PSV and n-PSV significantly reduced the PTPdi per minute, compared with that during a T-piece trial (204.4 +/- 93.8 cm H(2)O x s/min [i-PSV]; 197.5 +/- 119.8 [n-PSV]; 393.8 +/- 129.0 [T-piece]). Expired tidal volume (VTe) was significantly higher (p < 0.05) during n-PSV (615 +/- 166 ml) than during i-PSV (519 +/- 140 ml). The respiratory pump (PTPdi/VTe) was more effective (p < 0.05) with noninvasive ventilation (22.3 +/- 2.3 cm H(2)O x s/L for i-PSV versus 17.2 +/- 3.3 for n-PSV). RL and EL were similar with the two modes of ventilation. Overall dyspnea was significantly (p < 0.05) better during n-PSV than i-PSV, whereas ABG were similar. We have shown, in patients affected by stable chronic respiratory disorders not ready to sustain totally spontaneous breathing, that i-PSV and n-PSV are equally effective in reducing the PTPdi and in improving ABG, but that n-PSV seems to be better tolerated.

Comparison of two methods for weaning patients with chronic obstructive pulmonary disease requiring mechanical ventilation for more than 15 days

We designed a prospective multicenter randomized controlled study in three long-term weaning units (LWU) to evaluate which protocol, inspiratory pressure support ventilation (PSV) or spontaneous breathing trials (SB), is more effective in weaning patients with chronic obstructive pulmonary disease (COPD) requiring mechanical ventilation for more than 15 d. Fifty-two of 75 patients, failing an initial T-piece trial at admission, were randomly assigned to PSV or SB (26 in both groups). No significant difference was found in weaning success rate (73% versus 77% in the PSV and SB group, respectively), mortality rate (11.5% versus 7.6%), duration of ventilatory assistance (181 +/- 161 versus 130 +/- 106 h), LWU (33 +/- 12 versus 35 +/- 19 d), or total hospital stay. The results of these defined protocols were retrospectively compared with an "uncontrolled clinical practice" in weaning historical control patients. The overall 30-d weaning success rate was significantly greater (87% versus 70%) and the time spent under mechanical ventilation by survived and weaned patients was shorter in the patients in the study than in historical control patients (103 +/- 144 versus 170 +/- 127 h). The LWU and hospital stays were also significantly shorter (27 +/- 12 versus 38 +/- 18 and 38 +/- 17 versus 47 +/- 18 d). Spontaneous breathing trials and decreasing levels of PSV are equally effective in difficult-to-wean patients with COPD. The application of a well-defined protocol, independent of the mode used, may result in better outcomes than uncontrolled clinical practice.

Effect of pulmonary rehabilitation on exhaled nitric oxide in patients with chronic obstructive pulmonary disease

BACKGROUND

In patients with mild to moderate chronic obstructive pulmonary disease (COPD) the exercise induced increase in exhaled nitric oxide (eNO) parallels that observed in normal untrained subjects. There is no information on the effects of the level of exercise tolerance on eNO in these patients. The aim of this study was to evaluate the effect of a pulmonary rehabilitation programme including exercise training on eNO in patients with COPD.

METHODS

In 14 consecutive male patients with stable COPD of mean (SD) age 64 (9) years and forced expiratory volume in one second (FEV1) 55 (14)% predicted, fractional eNO concentration (FeNO), peak work rate (Wpeak) and oxygen uptake (VO2peak) were assessed at baseline (T-1), at the end of a 1 month run in period (T0), and after an 8 week outpatient multidisciplinary pulmonary rehabilitation programme (T1) including cycloergometer training.

RESULTS

FeNO did not significantly differ at T-1 and T0 (mean (SE) 4.3 (0.6) and 4.4 (0.6) ppb, respectively), whereas it rose significantly at T1 to 6.4 (0.7) ppb (p<0.02). Compared with T0, both Wpeak and VO2 were significantly (p<0.05) increased at T1 (mean (SE) Wpeak from 89 (5.6) W to 109 (6.9) W); VO2peak from 1.27 (0.1) l/min to 1.48 (0.1) l/min). A significant correlation was found between baseline FEV1 and the change in FeNO following the rehabilitation programme (r=-0.71; p<0.05) and between changes in FeNO and Wpeak from T0 to T1(r=0.60; p<0.05).

CONCLUSIONS

Pulmonary rehabilitation in patients with mild to moderate COPD is associated with an increase in exhaled nitric oxide.

Effect of pulmonary rehabilitation on exhaled nitric oxide in patients with chronic obstructive pulmonary disease

BACKGROUND

In patients with mild to moderate chronic obstructive pulmonary disease (COPD) the exercise induced increase in exhaled nitric oxide (eNO) parallels that observed in normal untrained subjects. There is no information on the effects of the level of exercise tolerance on eNO in these patients. The aim of this study was to evaluate the effect of a pulmonary rehabilitation programme including exercise training on eNO in patients with COPD.

METHODS

In 14 consecutive male patients with stable COPD of mean (SD) age 64 (9) years and forced expiratory volume in one second (FEV1) 55 (14)% predicted, fractional eNO concentration (Feno), peak work rate (Wpeak) and oxygen uptake (V˙o2peak) were assessed at baseline (T–1), at the end of a 1 month run in period (T0), and after an 8 week outpatient multidisciplinary pulmonary rehabilitation programme (T1) including cycloergometer training.

RESULTS

Fenodid not significantly differ at T–1 and T0 (mean (SE) 4.3 (0.6) and 4.4 (0.6) ppb, respectively), whereas it rose significantly at T1 to 6.4 (0.7) ppb (p<0.02). Compared with T0, both Wpeak andV˙o2 were significantly (p<0.05) increased at T1 (mean (SE) Wpeak from 89 (5.6) W to 109 (6.9) W);V˙o2peak from 1.27 (0.1) l/min to 1.48 (0.1) l/min). A significant correlation was found between baseline FEV1 and the change in Feno following the rehabilitation programme (r=–0.71; p<0.05) and between changes in Feno and Wpeak from T0 to T1(r=0.60; p<0.05).

CONCLUSIONS

Pulmonary rehabilitation in patients with mild to moderate COPD is associated with an increase in exhaled nitric oxide.

Exhaled nitric oxide in patients with PiZZ phenotype-related alpha1-anti-trypsin deficiency

There is no report of exhaled NO (eNO) in subjects with different phenotypes of alpha1-anti-trypsin (AAT) deficiency. Exhaled nitric oxide was evaluated by means of single-breath chemiluminescence analysis (fractional exhaled concentration at the plateau level [plFE(NO)]) in 40 patients with AAT deficiency. Patients were divided according to the protease inhibitor (Pi) phenotype: PiMZ/MS, n = 25; PiSZ n = 6; PiZZ, n = 9. Nineteen healthy subjects served as controls. Levels of eNO in PiZZ patients were also compared with those of subjects, without AAT deficiency (PiMM), matched for diagnosis, sex, age, smoking habit and forced expiratory volume in 1 sec (FEV1). In AAT deficiency subjects airway hyper-responsiveness to methacholine (PD20 FEV1) was also assessed. plFE(NO) was significantly lower in the PiZZ group (4.5+/-1.4 ppb) than in matched PiMM subjects (8.2+/-3.8 ppb), in healthy controls (9.3+/-2.8 ppb) and in patients of other phenotypes. Dynamic lung volumes and DL(CO) were significantly lower in PiZZ than in other AAT-deficient patients. Bronchial hyper-responsiveness was not different among AAT phenotypes. These results suggest that eNO may be significantly reduced in PiZZ as compared to healthy control subjects and to AAT subjects with other phenotypes, independent of the level of airway obstruction. Whether, at least potentially, eNO may be considered as an early marker of lung involvement in AAT deficiency must be confirmed with studies on larger number of subjects.

The appropriate setting of noninvasive pressure support ventilation in stable COPD patients

STUDY OBJECTIVE

To evaluate the short-term physiologic effects of two settings of nasal pressure-support ventilation (NPSV) in stable COPD patients with chronic hypercapnia.

DESIGN

Randomized controlled physiologic study.

SETTING

Lung function units and outpatient clinic of two affiliated pulmonary rehabilitation centers.

PATIENTS

Twenty-three patients receiving domiciliary nocturnal NPSV for a mean (+/- SD) duration of 31 +/- 20 months.

METHODS

Evaluation of arterial blood gases, breathing pattern, respiratory muscles, and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) during both unassisted and assisted ventilation. Two settings of NPSV were randomly applied for 30 min each: (1) usual setting (U), the setting of NPSV actually used by the individual patient at home; and (2) physiologic setting (PHY), the level of inspiratory pressure support (IPS) and external positive end-expiratory pressure (PEEPe) tailored to patient according to invasive evaluation of respiratory muscular function and mechanics.

RESULTS

All patients tolerated NPSV well throughout the procedure. Mean U was IPS, 16 +/- 3 cm H(2)O and PEEPe, 3.6 +/- 1.4 cm H(2)O; mean PHY was IPS, 15 +/- 3 cm H(2)O and PEEPe, 3.1 +/- 1.6 cm H(2)O. NPSV was able to significantly (p < 0.01) improve arterial blood gases independent of the setting applied. When compared with spontaneous breathing, both settings induced a significant increase in minute ventilation (p < 0.01). Both settings were able to reduce the diaphragmatic pressure-time product, but the reduction was significantly greater with PHY (by 64%; p < 0.01) than with U (56%; p < 0.05). Eleven of 23 patients (48%) with U and 7 of 23 patients (30%) with PHY showed ineffective efforts (IE); the prevalence of IE (20 +/- 39% vs 6 +/- 11% of their respiratory rate with U and PHY, respectively) was statistically different (p < 0.05).

CONCLUSION

In COPD patients with chronic hypercapnia, NPSV is effective in improving arterial blood gases and in unloading inspiratory muscles independent of whether it is set on the basis of patient comfort and improvement in arterial blood gases or tailored to a patient's respiratory muscle effort and mechanics. However, setting of inspiratory assistance and PEEPe by the invasive evaluation of lung mechanics and respiratory muscle function may result in reduction in ineffective inspiratory efforts. These short-term results must be confirmed in the long-term clinical setting.

Production of endogenous nitric oxide in chronic obstructive pulmonary disease and patients with cor pulmonale. Correlates with echo-Doppler assessment

Exhaled nitric oxide (NO) production in stable chronic obstructive pulmonary disease (COPD) has been loosely related to the severity of illness, being significantly reduced in the most severe cases. Pulmonary hypertension is associated with lower NO output from the lung. In this study expired NO was measured in patients with severe stable COPD with or without cor pulmonale (CP). Echocardiographic estimates of right heart function, lung function, diffusion capacity, respiratory muscle strength, and arterial blood gases were obtained in 34 consecutive patients with stable COPD (mean age, 68 +/- 7 yr). Expired NO was measured by chemiluminiscence to obtain fractional exhaled concentrations at peak (FENOp) and at plateau (FENOpl) points of the single-breath curve and resting NO output (V NO). All measurements of expired NO output, FENOp, FENOpl and V NO showed a negative correlation with both systolic pulmonary artery pressure (Pspa) (r = -0.51, -0.63, and -0.63, respectively, p < 0.01 for all) and right ventricle wall dimension (r = -0.41, -0.59, and -0.43, respectively, p < 0.05 for all), but not with any measurement of lung function. When the patients were divided according to the Pspa using a cutoff limit of 35 mm Hg, those subjects with CP showed lower FENOp (13.2 +/- 4.0 versus 36.7 +/- 30.8 ppb, p < 0.05), FENOpl (5.7 +/- 1.9 versus 8.9 +/- 4.7 ppb, p < 0.05), and V NO (69. 2 +/- 5.6 versus 107.6 +/- 14.6 nl/ min, p = 0.02) than did those with a normal resting Pspa. NO production from the airways was significantly lower and inversely related to development of CP in patients with severe COPD. Impaired endothelial release may account for the reduced levels of expired NO.

Physiologic effects of early administered mask proportional assist ventilation in patients with chronic obstructive pulmonary disease and acute respiratory failure

OBJECTIVE

To evaluate the physiologic short-term effects of noninvasive proportional assist ventilation (PAV) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD).

DESIGN

Prospective, physiologic study.

SETTING

Respiratory intermediate intensive care unit.

PATIENTS

Seven patients with acute respiratory failure requiring noninvasive mechanical ventilation because of exacerbation of COPD.

INTERVENTIONS

PAV was administered by nasal mask as first ventilatory intervention. The setting of PAV involved a procedure to adjust volume assist and flow assist to levels corresponding to patient comfort. Volume assist was also set by means of the "run-away" procedure. Continuous positive airway pressure (CPAP) amounting to 2 cm H2O was always set by the ventilator. This setting of assistance (PAV) was applied for 45 mins. Thereafter, CPAP was increased to 5 cm H2O (PAV + CPAP-5) without any change in the PAV setting and was administered for 20 mins. Oxygen was delivered through a port of the mask in the attempt to maintain a target SaO2 >90%.

MEASUREMENTS AND MAIN RESULTS

Arterial blood gases, breathing pattern, and inspiratory effort were measured during unsupported breathing and at the end of PAV, and breathing pattern and inspiratory effort were measured after 20 mins of PAV + CPAP-5. PAV determined a significant increase in tidal volume and minute ventilation (+64% and +25% on average, respectively) with unchanged breathing frequency and a significant improvement in arterial blood gases (PaO2 with the same oxygen supply, from 65 +/- 15 torr to 97 +/- 36 torr; PaCO2, from 80 +/- 11 torr to 76 +/- 13 torr; pH, from 7.30 +/- 0.02 to 7.32 +/- 0.03). The pressure-time product calculated over a period of 1 min (from 318 +/- 87 to 205 +/- 145 cm H2O x sec x min(-1)) was significantly reduced. PAV + CPAP-5 resulted in a further although not significant decrease in the pressure-time product calculated over a period of 1 min (to 183 +/- 110 cm H2O x sec x min(-1)), without additional changes in the breathing pattern.

CONCLUSIONS

Noninvasive PAV is able to improve arterial blood gases while unloading inspiratory muscles in patients with acute exacerbation of COPD.

Preliminary results on nursing workload in a dedicated weaning center

OBJECTIVE

To evaluate the nursing time required for difficult-to-wean patients in a dedicated weaning center (WC) and to examine the correlation of the nursing time with nursing workload (NW) scores and with clinical severity and dependency.

SETTING

Four-bed WC of a pulmonary rehabilitation department.

INTERVENTION

None.

DESIGN AND MEASUREMENT

Prospective, observational study of 46 consecutive patients admitted to a long-term WC. Time required by items of the Time Oriented Score System (TOSS) and other tasks specific to respiratory intermediate intensive care units were evaluated for all the activities performed on each patient in the first 2 days after admission. Patient dependency and level of nursing care at admission were measured using the Dependence Nursing Scale (DNS) and the Intermediate Therapeutic Intervention Score System (TISS-int). The Acute Physiology and Chronic Health Evaluation (APACHE) II score was also recorded at admission.

RESULTS

On the first day each patient needed 45 +/- 15% (63 +/- 23%, 45 +/- 22%, and 29 +/- 14% for the three nursing shifts) of allocated single nursing time. On the TOSS on the first day patients required a daily mean 28 +/- 10% of total available nursing time; on the second day the results did not change. Time of care in the first 24 h was only weakly related to DNS, APACHE II score, and TISS-int; only DNS was able (although weakly; r = 0.45) to predict minutes of nursing care.

CONCLUSIONS

In difficult-to-wean patients from mechanical ventilation the nursing time in the first 2 days after admission is high. The use of TOSS may underestimate NW by about 38%. Although only DNS showed the ability to predict minutes of care, the weak relationship limits its value in clinical practice.

Endogenous nitric oxide in patients with chronic heart failure (CHF): relation to functional impairment and nitrate-containing therapies

We assessed the levels of exhaled nitric oxide (eNO) in patients with chronic heart failure (CHF) according to the functional impairment and the use of nitrate-containing agents. Forty patients (age 55+/-9 years) were classified according to the NYHA classes I-II (n=18, group 1) and classes III-IV (n=22, group 2), and to the use of nitrate-containing drugs (Nitrate+, Nitrate-). Twenty-two healthy age-related subjects served as controls (group 3). Respiratory function, symptom-limited incremental cycloergometry and resting eNO concentration at peak (FENOp) or plateau (FENOpl) of the single-breath exhalation curve were assessed in all subjects. FENOpl was significantly lower in patients than in controls (7.8+/-2.7 and 10.6+/-2.8 ppb, respectively, P<0.005) and lower in most severe CHF patients (7.1+/-2.6 and 8.8+/-2.7 ppb in group 2 and group 1, respectively, P<0.05). A significant correlation between peak V'O(2), Watts and FENOpl (r=0.42, P<0.013 and r=0.46, P=0.008, respectively) was found. Independent of NYHA class, Nitrate+ showed higher FENOp levels than Nitrate- patients (36.9+/-15.7 vs. 28. 1+/-15.1 ppb, P<0.05). Resting eNO was lower in the most compromised CHF patients and was significantly related to exercise capacity. Nitrate-containing agents might influence the levels of eNO in these patients.

Exhaled nitric oxide and exercise in stable COPD patients

STUDY OBJECTIVE

To evaluate exhaled nitric oxide (eNO) during exercise in patients with stable COPD.

SETTING

Outpatient evaluation in a rehabilitation center.

PATIENTS

Eleven consecutive male patients with stable COPD (age, 65 +/- 6 years; FEV(1), 56 +/- 10% predicted). Eight healthy (six men; age, 51 +/- 16 years) nonsmoking, nonatopic volunteers served as control subjects.

METHODS

In each subject, a symptom-limited cycle ergometry test was performed by monitoring eNO with the tidal-breath method to assess eNO concentration (FENO) and output (VNO) at rest, peak exercise, and recovery time.

RESULTS

Resting FENO (9.8 +/- 5.1 and 14.1 +/- 6.3 parts per billion, respectively) and VNO (4.2 +/- 2.0 and 5.9 +/- 3.4 nmol/min, respectively) were lower, although not significantly, in COPD patients than in control subjects. In both groups, FENO significantly decreased whereas VNO significantly increased during exercise. Both variables returned to baseline during the recovery time. Peak exercise VNO, but not FENO, was significantly lower in COPD patients than in control subjects (7.9 +/- 5.4 and 12.7 +/- 6.0 nmol/min, respectively, p < 0.05). The rise in VNO was weakly correlated to oxygen consumption VO(2)) both in control subjects (r = 0.31, p = 0. 002) and in COPD patients (r = 0.22, p = 0.03). FENO showed an inverse correlation to VO(2) in both groups (r = -0.53, p = 0.000; r = -0.31, p = 0.003 in control subjects and COPD patients, respectively).

CONCLUSIONS

In patients with mild and moderate COPD, eNO during exercise parallels that observed in normal control subjects. VNO, but not FENO, is significantly reduced at peak exercise in COPD patients as compared with control subjects. The long-term effects of exercise training on eNO has to be evaluated by further studies.

Physiological effects of posture on mask ventilation in awake stable chronic hypercapnic COPD patients

Stable chronic hypercapnic patients are often prescribed long-term mask noninvasive pressure support ventilation (NPSV). There is a lack of information on the effects of posture on NPSV. Therefore posture induced changes in physiological effects of NPSV in awake stable chronic hypercapnic patients were evaluated. In 12 awake chronic obstructive pulmonary disease (COPD) patients breathing pattern, respiratory muscles, mechanics and dyspnoea (by visual analogue scale: VAS) were evaluated during spontaneous breathing (SB) in sitting posture and during NPSV in sitting, supine and lateral positions randomly assigned. Arterial blood gases were evaluated during SB and at the end of the last NPSV session (whatever the posture). As expected NPSV resulted in a significant improvement in carbon dioxide tension in arterial blood (Pa,CO2) (from 7.4+/-0.85 to 6.9+/-0.7 kPa). When compared with SB, sitting NPSV resulted in a significant increase in tidal volume and minute ventilation and in a significant decrease in breathing frequency. Inspiratory muscle effort as assessed by oesophageal pressure swings and pressure-time product per minute (from 14+/-4.8 to 6.2+/-3.5 cmH2O, and from 240+/-81 to 96+/-60 cmH2O x s x min(-1) respectively), intrinsic dynamic positive end expiratory pressure (from 2.7+/-2.3 to 1.4+/-1.3 cmH2O) and expiratory airway resistance (from 18+/-7 to 5+/-3 cmH2O x L x s(-1)) decreased during sitting NPSV, whereas VAS did not change. Changing posture did not significantly affect any parameter independently of the patients weight, whether obese or not. In awake stable hypercapnic chronic obstructive pulmonary disease patients changing posture does not significantly influence breathing pattern and respiratory muscles during noninvasive pressure support ventilation suggesting that mask ventilation may be performed in different positions without any relevant difference in its effectiveness.