The reversibility of increased airways resistance in chronic heart failure measured by impulse oscillometry

Airflow obstruction and chronic obstructive pulmonary disease are common in pulmonary tuberculosis even without sequelae findings on chest X-ray

PURPOSE

Pulmonary tuberculosis (TB) is a well-known risk factor for airflow obstruction and chronic obstructive pulmonary disease (COPD). The prognosis of TB without sequelae on chest X-ray (CXR) remains uncertain.

METHODS

We used the 2008-2009 Korea National Health and Nutrition Examination Survey (KNHANES) data and 2007-2012 KNHANES-matched Health Insurance Review and Assessment Service cohort data. Airflow obstruction was assessed using a pulmonary function test. COPD was defined using diagnostic codes and the use of COPD medication for 3-year. We classified subjects into three groups based on TB history and sequelae on CXR.

RESULTS

In 4911 subjects, the CXR(-) (no TB sequelae on CXR) post-TB group (n = 134) showed similar characteristics and normal lung function compared to that of the control group (n = 4,405), while the CXR(+) (TB sequelae on CXR) post-TB group (n = 372) showed different characteristics and reduced lung function. The prevalence of airflow obstruction was 9.3%, 13.4%, and 26.6% in control, CXR(-) post-TB, and CXR(+) post-TB groups, respectively. COPD was more common in the post-TB with CXR(+) (6.5%) or without CXR (-) (4.5%) groups, than in the control group (1.8%). Compared to the CXR(-) post-TB group, the control group showed a lower risk for airflow obstruction (OR, 0.774; p = .008). The CXR(+) post-TB group showed a higher risk for airflow obstruction (OR, 1.456; p = .011). The Control group also showed a lower risk for the development of COPD than the CXR(-) post-TB group (OR, 0.496; p = .011).

CONCLUSIONS

We need to educate TB patients that airway obstruction and COPD can easily develop, even if TB sequelae are not observed on CXR.

The interactions between respiratory and cardiovascular systems in systolic heart failure

Heart failure (HF) is a complex and multifaceted disease. The disease affects multiple organ systems, including the respiratory system. This review provides three unique examples illustrating how the cardiovascular and respiratory systems interrelate because of the pathology of HF. Specifically, these examples outline the impact of HF pathophysiology on 1) respiratory mechanics and the mechanical "cost" of breathing; 2) mechanical interactions of the heart and lungs; and on 3) abnormalities of pulmonary gas exchange during exercise, and how this may be applied to treatment. The goal of this review is to, therefore, raise the awareness that HF, though primarily a disease of the heart, is accompanied by marked pathology of the respiratory system.

Albuterol Improves Alveolar-Capillary Membrane Conductance in Healthy Humans

BACKGROUND

Beta-2 adrenergic receptors (β₂ARs) are located throughout the body including airway and alveolar cells. The β₂ARs regulate lung fluid clearance through a variety of mechanisms including ion transport on alveolar cells and relaxation of the pulmonary lymphatics. We examined the effect of an inhaled β₂-agonist (albuterol) on alveolar-capillary membrane conductance (DM) and pulmonary capillary blood volume (V_C) in healthy humans.

METHODS

We assessed the diffusing capacity of the lungs for carbon monoxide (DLCO) and nitric oxide (DLNO) at baseline, 30 minutes, and 60 minutes following nebulized albuterol (2.5 mg, diluted in 3 mL normal saline) in 45 healthy subjects. Seventeen subjects repeated these measures following nebulized normal saline (age = 27 ± 9 years, height = 165 ± 21 cm, weight = 68 ± 12 kg, BMI = 26 ± 9 kg/m²). Cardiac output (Q), heart rate, systemic vascular resistance (SVR), blood pressure, oxygen saturation, forced expiratory volume at one-second (FEV₁), and forced expiratory flow at 50% of forced vital capacity (FEF₅₀) were assessed at baseline, 30 minutes, and 60 minutes following the administration of albuterol or saline.

RESULTS

Albuterol resulted in a decrease in SVR, and an increase in Q, FEV₁, and FEF₅₀ compared to saline controls. Albuterol also resulted in a decrease in V_C at 60 minutes post albuterol. Both albuterol and normal saline resulted in no change in DLCO or DM when assessed alone, but a significant increase was observed in DM when accounting for changes in V_C.

CONCLUSION

These data suggest that nebulized albuterol improves pulmonary function in healthy humans, while nebulization of both albuterol and saline results in an increase in DM/V_C.

Chronic heart failure modifies respiratory mechanics in rats: a randomized controlled trial

Objective

To analyze respiratory mechanics and hemodynamic alterations in an experimental model of chronic heart failure (CHF) following myocardial infarction.

Method

Twenty-seven male adult Wistar rats were randomized to CHF group (n=12) or Sham group (n=15). Ten weeks after coronary ligation or sham surgery, the animals were anesthetized and submitted to respiratory mechanics and hemodynamic measurements. Pulmonary edema as well as cardiac remodeling were measured.

Results

The CHF rats showed pulmonary edema 26% higher than the Sham group. The respiratory system compliance (Crs) and the total lung capacity (TLC) were lower (40% and 27%, respectively) in the CHF rats when compared to the Sham group (P<0.01). There was also an increase in tissue resistance (Gti) and elastance (Hti) (28% and 45%, respectively) in the CHF group. Moreover, left ventricular end-diastolic pressure was higher (32 mmHg vs 4 mmHg, P<0.01), while the left ventricular systolic pressure was lower (118 mmHg vs 130 mmHg, P=0.02) in the CHF group when compared to the control. Pearson’s correlation coefficient showed a negative association between pulmonary edema and Crs (r=–0.70, P=0.0001) and between pulmonary edema and TLC (r=–0.67, P=0.0034). Pulmonary edema correlated positively with Gti (r=0.68, P=0.001) and Hti (r=0.68, P=0.001). Finally, there was a strong positive relationship between pulmonary edema and heart weight (r=0.80, P=0.001).

Conclusion

Rats with CHF present important changes in hemodynamic and respiratory mechanics, which may be associated with alterations in cardiopulmonary interactions.

Phenotype of Spirometric Impairment in an Aging Population

RATIONALE

The Global Lung Initiative (GLI) provides age-appropriate criteria for establishing spirometric impairment, including mild, moderate, and severe chronic obstructive pulmonary disease (COPD) and restrictive pattern, but its association with respiratory-related phenotypes has not been evaluated.

OBJECTIVES

To evaluate respiratory-related phenotypes in GLI-defined spirometric impairment.

METHODS

In COPDGene (N = 10,131 patients; age range, 45-81 yr; average smoking history, 44.3 pack-years), we evaluated spirometry, dyspnea (modified Medical Research Council grade, ≥2), poor respiratory health-related quality of life (St. George's Respiratory Questionnaire total score, ≥25), poor exercise performance (6-minute-walk distance, <391 m), bronchodilator reversibility (FEV1 change, >12% and ≥200 ml), and computed tomography-diagnosed emphysema and gas trapping (>5% and >15% of lung, respectively).

MEASUREMENTS AND MAIN RESULTS

GLI established normal spirometry in 5,100 patients (50.3%), mild COPD in 669 (6.6%), moderate COPD in 865 (8.5%), severe COPD in 2,522 (24.9%), and restrictive pattern in 975 (9.6%). Relative to normal spirometry, graded associations with respiratory-related phenotypes were found for mild, moderate, and severe COPD, with respective adjusted odds ratios (95% confidence intervals) as follows: dyspnea-1.31 (1.10-1.56), 2.20 (1.81-2.68), and 10.73 (8.04-14.33); poor respiratory health-related quality of life-1.49 (1.28-1.75), 2.69 (2.08-3.47), and 14.61 (10.09-21.17); poor exercise performance-1.11 (0.94-1.31), 1.58 (1.33-1.88), and 4.58 (3.42-6.12); bronchodilator reversibility-2.76 (2.24-3.40), 5.18 (4.29-6.27), and 6.21 (5.06-7.62); emphysema-4.86 (3.16-7.47), 6.41 (4.09-10.05), and 17.79 (10.79-29.32); and gas trapping-3.92 (3.12-4.93), 5.20 (3.82-7.07), and 16.28 (9.71-27.30). Restrictive pattern was also associated with multiple respiratory-related phenotypes at a level similar to moderate COPD, but it was otherwise not associated with emphysema (0.89 [0.60-1.32]) or gas trapping (1.15 [0.92-1.42]).

CONCLUSIONS

GLI-defined spirometric impairment establishes clinically meaningful respiratory disease, as validated by graded associations with respiratory-related phenotypes.

Acute decompensated heart failure is routinely treated as a cardiopulmonary syndrome

BACKGROUND

Heart failure as recognized and treated in typical practice may represent a complex condition that defies discrete categorizations. To illuminate this complexity, we examined treatment strategies for patients hospitalized and treated for decompensated heart failure. We focused on the receipt of medications appropriate for other acute conditions associated with shortness of breath including acute asthma, pneumonia, and exacerbated chronic obstructive pulmonary disease.

METHODS AND RESULTS

Using Premier Perspective(®), we studied adults hospitalized with a principal discharge diagnosis of heart failure and evidence of acute heart failure treatment from 2009-2010 at 370 US hospitals. We determined treatment with acute respiratory therapies during the initial 2 days of hospitalization and daily during hospital days 3-5. We also calculated adjusted odds of in-hospital death, admission to the intensive care unit, and late intubation (intubation after hospital day 2). Among 164,494 heart failure hospitalizations, 53% received acute respiratory therapies during the first 2 hospital days: 37% received short-acting inhaled bronchodilators, 33% received antibiotics, and 10% received high-dose corticosteroids. Of these 87,319 hospitalizations, over 60% continued receiving respiratory therapies after hospital day 2. Respiratory treatment was more frequent among the 60,690 hospitalizations with chronic lung disease. Treatment with acute respiratory therapy during the first 2 hospital days was associated with higher adjusted odds of all adverse outcomes.

CONCLUSIONS

Acute respiratory therapy is administered to more than half of patients hospitalized with and treated for decompensated heart failure. Heart failure is therefore regularly treated as a broader cardiopulmonary syndrome rather than as a singular cardiac condition.

Study the mechanical pulmonary changes in patients with congestive heart failure (CHF) by impulse oscillometry

BACKGROUND

Heart failure is one of the most leading cause of death worldwide, but the mechanical characteristics of the pulmonary system in these patients have not been studied enough. The aim of this study was to measure mechanical pulmonary changes in patients with congestive heart failure (CHF) by using impulse oscillometry (IOS), which can obtain data by simpler means and independently from respiratory muscle strength.

MATERIALS AND METHODS

We assessed 24 CHF patients and 24 controls by spirometry and IOS using the Jaeger IOS system. IOS measures central and peripheral airway resistances (R20, R5) and central and peripheral reactances (X20, X5) using sound waves with different frequencies, which superimposed on the patients respiratory tidal volume and then records reflects. P value < 0.05 was taken to be significant.

RESULTS

The mean age of patients and controls was 61 ± 10 and 57 ± 7 years, respectively. The mean ejection fraction (EF) was 37 ± 17% for patients and 55 ± 7% for controls. Patients had a lower X5 (-0.20 ± 0.13 vs -0.13 ± 0.07; P < 0.05), forced expiratory volume in 1 second (FEV1; 2.26 ± 0.68 vs 3.09 ± 0.82: P < 0.01 L/min), and forced vital capacity (FVC; 2.55 ± 0.86 vs 3.32 ± 0.87; P < 0.05) compared to the controls. They also had elevated R5: 0.37 ± 0.21 vs 0.27 ± 0.09; P < 0.06). X5 was correlated with spirometric abnormalities (P < 0.05) and was lower in patients than in controls.

CONCLUSION

X5 was lower and R5 was higher in patients than in controls. CHF patients can be assessed by IOS more comfortable than by spirometry. IOS can reliably measure peripheral airway resistance in this group of patients.

Bronchodilator responsiveness in patients with chronic heart failure

OBJECTIVE

The aim of this study was to evaluate the effect of inhaled bronchodilators on pulmonary function and dyspnea in patients with chronic heart failure (HF).

BACKGROUND

Conflicting data exist on whether bronchodilators may improve pulmonary function and dyspnea in patients with chronic HF.

METHODS

In this retrospective observational study we analyzed data of 116 chronic HF outpatients with systolic dysfunction who underwent spirometry and Borg dyspnea measurements before and after inhalation of 400 μg salbutamol and 80 μg ipratropium. Patients with chronic obstructive pulmonary disease (COPD) or asthma were excluded.

RESULTS

Bronchodilators fully reversed airway obstruction (AO) in 25 of 64 (39.1%) patients with pre-bronchodilator AO. All spirometric measurements, except for forced vital and inspiratory capacities, improved significantly post-bronchodilation. Absolute and percent improvements in forced expiratory volume in 1 s (FEV1) were more pronounced in patients with persistent AO post-bronchodilation compared to those without AO (0.19 ± 0.18 L and 8.4 ± 7.3% versus 0.11 ± 0.12 L and 4.3 ± 4.0%, p < 0.05). Significant bronchodilator responsiveness of FEV1 (>200 mL and >12%) was noted in 12.1% and was more frequent in patients with persistent AO and fully reversible AO than in those without AO (23.1% and 16.0% versus 1.9%, p < 0.05). We measured a small, albeit significant improvement in dyspnea (0.7 ± 1.2 versus 0.9 ± 1.3, p = 0.002).

CONCLUSIONS

Inhaled bronchodilators may have an additional role in the management of patients with chronic HF because of their potential to improve pulmonary function, especially in those with AO. The clinical usefulness and possible adverse events of bronchodilators need to be further established.

Physiological measurement of the small airways

Noninvasive physiological measurements are reviewed that have been reported in the literature with the specific aim being to study the small airways in lung disease. This has mostly involved at-the-mouth noninvasive measurement of flow, pressure or inert gas concentration, with the intent of deriving one or more indices that are representative of small airway structure and function. While these measurements have remained relatively low-tech, the effort and sophistication increasingly reside with the interpretation of such indices. When aspiring to derive information at the mouth about structural and mechanical processes occurring several airway generations away in a complex cyclically changing cul-de-sac structure, conceptual or semi-quantitative lung models can be valuable. Two assumptions that are central to small airway structure-function measurement are that of an average airway change at a given peripheral lung generation and of a parallel heterogeneity in airway changes. While these are complementary pieces of information, they can affect certain small airways tests in confounding ways. We critically analyzed the various small airway tests under review, while contending that negative outcomes of these tests are probably a true reflection of the fact that no change occurred in the small airways. Utmost care has been taken to not favor one technique over another, given that most current small airways tests still have room for improvement in terms of rendering their content more specific to the small airways. One way to achieve this could consist of the coupling of signals collected at the mouth to spatial information gathered from imaging in the same patient.

The resistive and elastic work of breathing during exercise in patients with chronic heart failure

Patients with heart failure (HF) display numerous derangements in ventilatory function, which together serve to increase the work of breathing (W(b)) during exercise. However, the extent to which the resistive and elastic properties of the respiratory system contribute to the higher W(b) in these patients is unknown. We quantified the resistive and elastic W(b) in patients with stable HF (n = 9; New York Heart Association functional class I-II) and healthy control subjects (n = 9) at standardised levels of minute ventilation (V'(E)) during graded exercise. Dynamic lung compliance was systematically lower for a given level of V'(E) in HF patients than controls (p<0.05). HF patients displayed slightly higher levels of inspiratory elastic W(b) with greater amounts of ventilatory constraint and resistive W(b) than control subjects during exercise (p<0.05). Our data indicates that the higher W(b) in HF patients is primarily due to a greater resistive, rather than elastic, load to breathing. The greater resistive W(b) in these patients probably reflects an increased hysteresivity of the airways and lung tissues. The marginally higher inspiratory elastic W(b) observed in HF patients appears related to a combined decrease in the compliances of the lungs and chest wall. The clinical and physiological implications of our findings are discussed.

A history of ischemic heart disease is a common cause of wheezing in the elderly of a Japanese local community

OBJECTIVE

We conducted a cross-sectional study to investigate which factors have a significant impact on wheezing and QOL in the elderly of a Japanese local community.

METHODS

In 2008, 527 participants (250 participants aged 45 to 64 years and 277 participants aged 65 to 88 years) responded to the questionnaire regarding wheezing and disease history. QOL was evaluated by the Short Form-8. The participants underwent airway reversibility testing. The plasma levels of IgE were measured. The plasma levels of N-terminal-pro-B-type natriuretic peptide were measured in twenty-one participants with a history of ischemic heart disease and in thirty-five age-matched participants without that history.

RESULTS

Wheezing was reported by 50 (9.5%) participants and was associated with a lower score of QOL. In multivariate analysis, wheezing was associated with sex (OR 3.12, CI 1.10-9.67) and a history of bronchial asthma (OR 22.3, CI 6.50-84.0) among participants aged 45 to 64 years. Among participants aged 65 and over, wheezing was associated with a history of bronchial asthma (OR 4.86, CI 1.39-15.1) and ischemic heart disease (OR 5.12, CI 1.61-15.0). Participants with both a history of ischemic heart disease and wheezing showed higher levels of N-terminal-pro-B-type natriuretic peptide. Airway reversibility was only associated with a history of ischemic heart disease (OR 4.65, CI 1.26-17.6).

CONCLUSION

It is suggested that bronchial asthma and heart disease are both significant causes of wheezing and affect the QOL in the elderly of a Japanese local community.

Assessment of respiratory mechanics by impulse oscillometry in orthopneic patients with acute left ventricular failure

BACKGROUND

This study investigated the respiratory function and mechanics of patients with orthopnea caused by acute left ventricular failure (ALVF).

METHODS

The study comprised 40 patients with ALVF and 15 control subjects. All patients underwent lung function tests and impulse oscillometry in both sitting and supine positions. In a subgroup of 22 patients, isosorbide dinitrate was administered and impulse oscillometry was performed 15 minutes later in the supine position.

RESULTS

No patient reported dyspnea while seated, and the orthopnea score was 2.9 ± 1.4. Left ventricular ejection fraction was 43% ± 10%. Patients demonstrated restrictive spirometric pattern in the sitting position, whereas functional residual capacity was comparable to that of the control group. In the supine position, all pulmonary volumes decreased, except inspiratory capacity which increased. Respiratory reactance (Xrs5) was higher in patients in both sitting (421.8 ± 630.6%pred vs 147.2 ± 72.8%pred, P = .01) and supine (699.8 ± 699.9%pred vs 251.2 ± 151.6%pred, P ≤ .001) positions. Respiratory resistance (Rrs5) (10.6% ± 17.8% mean decrease) and Xrs5 (17.2% ± 39.4% mean decrease) improved after nitrates administration. Orthopnea was better correlated with Xrs5%pred in the supine position (r = .42, P = .007). Ejection fraction was positively correlated with inspiratory capacity %pred (r = .42, P = .007) in the sitting position.

CONCLUSION

Patients with ALVF demonstrated increased respiratory reactance that correlated with orthopnea severity and improved after nitrates administration.

Should acute treatment with inhaled beta agonists be withheld from patients with dyspnea who may have heart failure?

In patients with dyspnea, prehospital and emergency providers make therapeutic decisions before a diagnosis is established. Inhaled beta-2 agonists are frontline treatment for patients with dyspnea due to asthma or chronic obstructive pulmonary disease (COPD) exacerbations. However, these agents have been associated with increased adverse events when administered chronically to heart failure patients. Our goal was to determine the safety and efficacy of acute administration of inhaled beta-2 agonists to patients with heart failure. MEDLINE and EMBASE searches were performed using the terms "beta agonists," "albuterol," "congestive heart failure," and "pulmonary edema." Bibliographies of relevant articles were searched. Only studies addressing acute effects of beta-2 agonists were included for analysis. Twenty-four studies comprising 434 patients were identified that addressed the acute delivery of beta-2 agonists in subjects with heart failure--five studies with inhaled administration and 19 with systemic administration. No study directly evaluated the effects of inhaled beta-2 agonists to patients with acutely decompensated heart failure. Treatment of heart failure patients with beta-2 agonists resulted in transient improvements in pulmonary function and cardiovascular hemodynamics. Only one investigation reported an association between beta-2 agonist use and an increase in malignant dysrhythmias. Investigations in animal models of heart failure and acute lung injury demonstrated resolution of pulmonary edema with beta agonist administration. There is insufficient evidence to suggest that acute treatment with inhaled beta-2 agonists should be avoided in patients with dyspnea who may have heart failure. Based on small studies and indirect evidence, administration of beta-2 agonists to patients with heart failure seems to improve pulmonary function, cardiovascular hemodynamics, and resorption of pulmonary edema. Although an increase in adverse effects with the use of beta-2 agonists cannot be ruled out based on these data, there was no evidence of an increase in clinically significant dysrhythmias, especially when administered by inhalation. Based on these findings, further study should focus on the clinical outcomes of patients with acutely decompensated heart failure who are treated with inhaled beta-2 agonist therapy.

Why does chronic heart failure cause breathlessness and fatigue?

Traditional explanations for the symptoms of fatigue and breathlessness experienced by patients with chronic heart failure (CHF) focus on how reduced cardiac output on exercise leads to impaired skeletal muscle blood supply, thus causing fatigue, and on how the requirement for a raised left ventricular filling pressure to maintain cardiac output results in reduced pulmonary diffusion owing to interstitial edema, thus causing breathlessness. However, indices of left ventricular function relate poorly to exercise capacity and symptoms, suggesting that the origin of symptoms may lie elsewhere. There is a specific heart failure myopathy that is present early in the condition which may contribute largely to the sensation of fatigue. Receptors present in skeletal muscle sensitive to work (ergoreceptors) are overactive in patients with CHF, presumably as a consequence of the myopathy, and their activity is related both to the ventilatory response to exercise and breathlessness, and to the sympathetic overactivity of CHF. In the present paper, we review the systemic consequences of left ventricular dysfunction to understand how they relate to the symptoms of heart failure.