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PubMed1993

Effects of smoked substance abuse on nonspecific airway hyperresponsiveness.

Previous data suggest that regular tobacco smoking may lead to nonspecific airway hyperresponsiveness (AHR) independent of airway obstruction, possibly because of effects on bronchial inflammation or mucosal permeability. Little is known concerning the effects on AHR of other widely smoked substances besides tobacco such as marijuana or cocaine. The smoke of both marijuana and cocaine contains respiratory irritants that elicit cough and produce abnormalities in airway dynamics and bronchial mucosal histopathology in habitual smokers. Therefore, regular smoking of one or both of these illicit substances could cause AHR or augment the AHR associated with tobacco smoking. The present study examined the influence of habitual smoking of marijuana, cocaine, and/or tobacco on nonspecific AHR in 542 (456 male) healthy participants (mean age, 34.8 +/- 6.8 SD yr) in an ongoing cohort study of the pulmonary effects of habitual smoking of illicit substances. Subjects with a history of intravenous drug abuse, significant occupational exposures, asthma, or recent upper respiratory tract infection were excluded. Inhalation challenge studies were performed using solutions of diluent and methacholine chloride (1.25 to 25 mg/ml) aerosolized by a DeVilbiss no. 646 nebulizer attached to a breath-activated dosimeter inhaled by three to five inspiratory capacity breaths. Positive responses to methacholine were defined by > or = 20% or > or = 10% declines in FEV1 from the postdiluent control value after inhalation of each concentration of methacholine. Participants were categorized by smoking status (nonsmoking and smoking of marijuana, cocaine, and/or tobacco alone and in combination); most analyses were performed in men and women separately.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1976

Regional lung function in chronic pulmonary congestion with and without mitral stenosis.

Relative regional ventilation and perfusion were measured with xenon-133 in 16 seated patients with pure or predominant mitral stenosis (group 1) and in 12 patients with chronic pulmonary congestion due to left-sided heart disease without mitral stenosis (group 2). The apex-base perfusion gradient was abnormally reduced and often reversed in group 1 patients. There was a significant negative correlation between perfusion gradient and mean pulmonary capillary pressure in both groups, but for a given elevation of pulmonary capillary pressure the perfusion gradient tended to be greater (i.e., less abnormal) in group 2. The regression line of perfusion gradient on pulmonary capillary pressure indicated that perfusion gradient had a value of zero (indicating reversal of the perfusion gradient) at a mean pulmonary capillary pressure of 26 mm Hg in group 2 but at only 18 mm Hg in group 1. Relative lower zone ventilation was abnormally reduced in group 1 and there was a significant negative correlation between ventilation gradient and pulmonary capillary pressure in group 1 but not group 2 patients. Comparison of the distribution of slowly inhaled small volume boluses, large volume boluses, and inspiratory capacity breaths of 133Xe suggested that the lower zone hypoventilation was due mainly to closure of peripheral airways but that selectively increased resistance and reduced compliance in the lower zones may contribute in some patients. Both ventilation and perfusion were reduced at the lung bases in group 1 patients, and between regions nonuniformity of relative ventilation/perfusion was significantly less than normal. Although ventilation distribution was relatively normal in group 2 patients, they also had significantly less regional ventilation/perfusion nonuniformity than normal subjects.

Adult↗
PubMed1981

Standardization of inhalation provocation tests: two techniques of aerosol generation and inhalation compared.

Comparison of methods of aerosol generation and inhalation is required to improve standardization of inhalation provocation tests. We compared two widely used methods in 10 asthmatics, by measuring the dose and distribution of radiolabeled aerosol deposited in the throat and lung, and the provocation concentration of inhaled histamine required to reduce the FEV1 by 20% (PC20). In one method, aerosol was generated by a DeVilbiss 646 nebulizer attached to a dosimeter, and was inhaled by 5 inspiratory capacity breaths. The measurements with each method were repeated once to determine the reproducibility of results. Both methods deposited the same dose in the lung, but the distribution of the dose was different; the dosimeter method deposited more aerosol in the throat and central airways. The PC20 obtained with each method was the same. The reproducibility of all measurements in the same subject was similar. The lung dose deposited by each method in different subjects varied to the same degree. The results indicated that the bronchial response to inhaled histamine can be measured as reliably using a nebulizer and tidal breathing as by a more complex dose-metering device. They also suggested that, when the methods are regulated as described, the PC20 will have the same clinical significance.

Adolescent↗
PubMed2006

Helium-hyperoxia, exercise, and respiratory mechanics in chronic obstructive pulmonary disease.

RATIONALE: Hyperoxia and normoxic helium independently reduce dynamic hyperinflation and improve the exercise tolerance of patients with chronic obstructive pulmonary disease (COPD). Combining these gases could have an additive effect on dynamic hyperinflation and a greater impact on respiratory mechanics and exercise tolerance. OBJECTIVE: To investigate whether helium-hyperoxia improves the exercise tolerance and respiratory mechanics of patients with COPD. METHODS: Ten males with COPD (FEV(1) = 47 +/- 17%pred [mean +/- SD]) performed randomized constant-load cycling at 60% of maximal work rate breathing air, hyperoxia (40% O(2), 60% N(2)), normoxic helium (21% O(2), 79% He), or helium-hyperoxia (40% O(2), 60% He). MEASUREMENTS: Exercise time, inspiratory capacity (IC), work of breathing, and exertional symptoms were measured with each gas. RESULTS: Compared with air (9.4 +/- 5.2 min), exercise time was increased with hyperoxia (17.8 +/- 5.8 min) and normoxic helium (16.7 +/- 9.1 min) but the improvement with helium-hyperoxia (26.3 +/- 10.6 min) was greater than both these gases (p = 0.019 and p = 0.007, respectively). At an isotime during exercise, all three gases reduced dyspnea and both helium mixtures increased IC and tidal volume. Only helium-hyperoxia significantly reduced the resistive work of breathing (15.8 +/- 4.2 vs. 10.1 +/- 4.1 L . cm H(2)O(-1)) and the work to overcome intrinsic positive end-expiratory pressure (7.7 +/- 1.9 vs. 3.6 +/- 2.1 L . cm H(2)O(-1)). At symptom limitation, tidal volume remained augmented with both helium mixtures, but IC and the work of breathing were unchanged compared with air. CONCLUSION: Combining helium and hyperoxia delays dynamic hyperinflation and improves respiratory mechanics, which translates into added improvements in exercise tolerance for patients with COPD.

Aged↗
PubMed2001

Dose-response effect of oxygen on hyperinflation and exercise endurance in nonhypoxaemic COPD patients.

Dynamic hyperinflation contributes to exertional breathlessness and reduced exercise tolerance in chronic obstructive pulmonary disease (COPD) patients. This study examined whether oxygen supplementation results in a dose-dependent decrease in hyperinflation associated with functional and symptomatic improvement. Ten severe COPD patients without clinically significant oxygen (O2) desaturation during exercise, and seven healthy subjects, performed five exercise tests at 75% of maximally tolerated work rate. Inspired oxygen fraction (FI,O2) was varied (0.21, 0.3, 0.5, 0.75 and 1.0) among tests in a randomized order. Ventilation (V'E) was measured, and end-inspiratory (EILV) and end-expiratory (EELV) lung volume changes were assessed from inspiratory capacity manoeuvres. In the patients, compared to room air, endurance time increased with FI,O2=0.3 (mean+/-SEM 92+/-20%) and increased further with FI,O2=0.5 (157+/-30%). At isotime, compared to room air, there were significant reductions in dyspnoea score, EELV, EILV, V'E and respiratory frequency (fR) with FI,O2=0.3. Improved endurance time negatively correlated with change in EELV (r=0.48, p=0.002) and EILV (r=0.43, p=0.005). The dyspnoea rating decrease correlated with fR decrease. In healthy subjects, smaller V'E and fR decreases were observed at FI,O2=0.5, accompanied by more modestly increased endurance. Oxygen supplementation during exercise induced dose-dependent improvement in endurance and symptom perception in nonhypoxaemic chronic obstructive pulmonary disease patients, which may be partly related to decreased hyperinflation and slower breathing pattern. This effect is maximized at an inspired oxygen fraction of 0.5.

Aged↗
PubMed2006

Mechanisms of dyspnoea and its language in patients with asthma.

This study hypothesises that regardless of the global score of dyspnoea intensity, different descriptors may be selected by asthmatic patients during short cardiopulmonary exercise test (sCPET) and methacholine (Mch) inhalation. It also examines whether different qualitative dyspnoea sensations can help explain the underlying mechanisms of the symptom. Minute ventilation (V'E), tidal volume (VT) and inspiratory capacity (IC) were measured in 22 stable asthmatic patients, and the sensation of dyspnoea during Mch inhalation and sCPET was quantitatively (Borg scale) and qualitatively (descriptors) assessed. The work rate and oxygen uptake (V'O2) were also measured during sCPET. Airway obstruction and hyperinflation, as measured by IC reduction, were the best correlates for dyspnoea with Mch. During sCPET, changes in WR, V'O2, V'E and VT significantly correlated with Borg score, with V'E being the best predictor of dyspnoea; IC decreased in eight patients. Furthermore, chest tightness (68%) was the highest reported descriptor during Mch inhalation, whereas work/effort (72%) was the highest during sCPET. In conclusion, obstruction/hyperinflation and work rate are highly reliable predictors of Borg rating of dyspnoea during methacholine inhalation and short cardiopulmonary exercise testing, respectively. Regardless of the global score of intensity dyspnoea, different descriptors may be selected by patients during short cardiopulmonary exercise testing and methacholine inhalation. Various qualities of dyspnoea result from different pathophysiological abnormalities.

Administration, Inhalation↗
PubMed2006

Does expiratory flow limitation predict chronic dyspnoea in adults with cystic fibrosis?

Tidal expiratory flow limitation (EFL) may promote dynamic hyperinflation and contribute to chronic dyspnoea. The purpose of this study was to assess the contribution of EFL to chronic dyspnoea in adults with cystic fibrosis (CF). The presence of EFL was determined in 102 adults with stable CF (forced expiratory volume in one second (FEV1) 17.3-91.5% predicted) and 20 age-matched control subjects using the negative expiratory pressure technique. Measurements of inspiratory capacity (IC) and spirometry were performed, and chronic dyspnoea was evaluated using the modified Medical Research Council scale. EFL was present in 34 subjects (33%), with 18 subjects flow limited in the sitting position and 16 subjects flow limited only in the supine position. Flow limitation in the sitting position was associated with older age and lower FEV1 compared with flow-limited supine position and non-flow-limited subjects. A significant reduction in IC accompanied EFL in both the sitting and supine positions. Flow limitation in the sitting position was associated with significantly higher levels of chronic dyspnoea. Ordinal regression analysis indicated that EFL was the best predictor of chronic dyspnoea in a model that included FEV1 % pred. Expiratory flow limitation in cystic fibrosis is associated with reduced forced expiratory volume in one second, older age and dynamic hyperinflation. Expiratory flow limitation significantly contributes to chronic dyspnoea in cystic fibrosis.

Adult↗
PubMed1999

Flow limitation and dyspnoea in healthy supine subjects during methacholine challenge.

The purpose of this study was to assess whether during standard methacholine (Mch) challenge (concentration up to 128 mg x mL(-1)) healthy supine subjects a) develop tidal expiratory flow limitation (FL) and hyperinflation, and b) whether the onset of tidal FL is associated with dyspnoea. Eight healthy subjects were studied. Dyspnoea was assessed using the Borg scale, FL by the negative expiratory pressure (NEP) method and hyperinflation in terms of decrease in inspiratory capacity (IC). Seven patients became flow limited at Mch doses ranging 4-64 mg x mL(-1), with FL encompassing 34-84% of the control tidal volume. In six of them the onset of tidal FL was associated with little or no dyspnoea and a modest degree of hyperinflation (deltaIC <-0.4 L). In one subject, however, onset of FL was associated with a substantial reduction in IC (0.58 L) and moderately severe dyspnoea. In all of these seven subjects FL was transiently reversed after an IC manoeuvre. In conclusion, the results show that a) most healthy subjects may develop flow limitation and hyperinflation during methacholine challenge in supine position, and b) at onset of flow limitation there is little or no dyspnoea, suggesting that onset of dynamic airway compression per se does not elicit significant dyspnoea. Significant dyspnoea probably only occurs with marked dynamic hyperinflation.

Adult↗
PubMed1994

Interactions of oxygen radicals with airway epithelium.

Reactive oxygen species (ROS) have been implicated in the pathogenesis of numerous disease processes. Epithelial cells lining the respiratory airways are uniquely vulnerable regarding potential for oxidative damage due to their potential for exposure to both endogenous (e.g., mitochondrial respiration, phagocytic respiratory burst, cellular oxidases) and exogenous (e.g., air pollutants, xenobiotics, catalase negative organisms) oxidants. Airway epithelial cells use several nonenzymatic and enzymatic antioxidant mechanisms to protect against oxidative insult. Nonenzymatic defenses include certain vitamins and low molecular weight compounds such as thiols. The enzymes superoxide dismutase, catalase, and glutatione peroxidase are major sources of antioxidant protection. Other materials associated with airway epithelium such as mucus, epithelial lining fluid, and even the basement membrane/extracellular matrix may have protective actions as well. When the normal balance between oxidants and antioxidants is upset, oxidant stress ensues and subsequent epithelial cell alterations or damage may be a critical component in the pathogenesis of several respiratory diseases. Oxidant stress may profoundly alter lung physiology including pulmonary function (e.g., forced expiratory volumes, flow rates, and maximal inspiratory capacity), mucociliary activity, and airway reactivity. ROS may induce airway inflammation; the inflammatory process may serve as an additional source of ROS in airways and provoke the pathophysiologic responses described. On a more fundamental level, cellular mechanisms in the pathogenesis of ROS may involve activation of intracellular signaling enzymes including phospholipases and protein kinases stimulating the release of inflammatory lipids and cytokines. Respiratory epithelium may be intimately involved in defense against, and pathophysiologic changes invoked by, ROS.

Animals↗
PubMed2007

Systemic cytokines, clinical and physiological changes in patients hospitalized for exacerbation of COPD.

BACKGROUND: Systemic inflammation in patients with COPD may worsen during exacerbations, but there is limited information relating levels of systemic inflammatory markers with symptoms and physiologic changes during an exacerbation METHODS: We measured dyspnea using the visual analog scale, pulmonary function tests, hemograms, and plasma levels for interleukin (IL)-6, IL-8, leukotriene B(4) (LTB4), tumor necrosis factor-alpha, and secretory leukocyte protease inhibitor (SLPI) in 20 patients on admission to a hospital for exacerbation of COPD (ECOPD), 48 h later (interim), and 8 weeks after hospital discharge (recovery). RESULTS: Dyspnea was present in all patients. Inspiratory capacity improved faster than FEV(1). Compared to recovery, there was a significant increase in the mean (+/- SD) hospital admission plasma levels of IL-6 (6.38 +/- 0.72 to 2.80 +/- 0.79 pg/mL; p = 0.0001), IL-8 (8.18 +/- 0.85 to 3.72 +/- 0.85 pg/mL; p = 0.002), and LTB4 (8,675 +/- 1,652 to 2,534 +/- 1,813 pg/mL; p = 0.003), and the percentages of segmented neutrophils (79 to 69%; p < 0.02) and band forms (7.3 to 1.0%; p < 0.01) in peripheral blood, with no changes in TNF-alpha and SLPI. There were significant correlations between changes in IL-6 (r = 0.61; p = 0.01) and IL-8 (r = 0.56; p = 0.04) with changes in dyspnea and levels of IL-6 (r = -0.51; p = 0.04) and TNF-alpha (r = -0.71; p < 0.02) with changes in FEV(1.) CONCLUSIONS: Hospitalized patients with ECOPDs experience significant changes in systemic cytokine levels that correlate with symptoms and lung function. An ECOPD represents not only a worsening of airflow obstruction but also increased systemic demand in a host with limited ventilatory reserve.

Aged↗
PubMed1998

Exercise limitation in obstructive lung disease.

OBJECTIVE: To study the relationship of resting pulmonary function to maximal exercise power output (Wmax) in obstructive lung disease (OLD). SETTING: University Hospital Pulmonary Function Laboratory. SUBJECTS: Twenty-five patients with OLD (6 with asthma and 19 with COPD). METHODS: Measurement of pulmonary lung function, resting arterial blood gases, and maximal symptom-limited exercise on a cycle ergometer. RESULTS AND CONCLUSIONS: In OLD, the only significant contributor to Wmax was the inspiratory capacity (r2 = 0.66; p < 0.001).

Blood Gas Analysis↗
PubMed1998

Assessing the reversibility of airway obstruction.

STUDY OBJECTIVE: To determine whether changes of partial expiratory flow-volume curve (PEFV) and inspiratory capacity (IC) detect functional responses to bronchodilator in patients who do not meet the FEV1 criteria for reversibility of airway obstruction. DESIGN/METHODS: The effects of salbutamol (200 microg by metered-dose inhaler) on lung function were examined in 50 patients with asthma and 28 patients with COPD. Measurements evaluated were FEV1, forced expiratory flow at 30% of control FVC from maximal expiratory flow-volume curve (Vm30), forced expiratory flow at 30% of control FVC from PEFV (Vp30), and IC. On a separate occasion, a representative sample of 26 subjects inhaled placebo to determine the 95% confidence limits (CLs) of each of the parameters. RESULTS: A percent and absolute increment of FEV1 above the upper CL was recorded in 28 patients. Of these, 26 had a percent and absolute increase of Vp30, 21 of Vm30, 9 of FVC, and 11 of IC above the 95% CL. Of the 50 patients who did not have an increase in FEV1 above the 95% CL, 25 had a percent and absolute increase in Vp30, 15 of Vm30, 3 of FVC, and 13 of IC above the 95% CL. On average, the percent and absolute increase Vp30 above the 95% CL significantly identified more responders than every other parameter. CONCLUSION: Increases in maximal flow detected by PEFV and/or changes in IC may be substantially obscured by the effects of inspiration to total lung capacity required for the measurement of FEV1 in patients with chronic bronchoconstriction. Decreases in functional residual capacity (FRC) manifested by an increase of IC occur because, in patients whose FRC is dynamically determined, bronchodilatation that increases maximal flow in the tidal breathing range allows patients to breathe at lower lung volumes. Changes of FEV1 frequently fail to detect significant functional response to bronchodilators in patients with chronic airflow obstruction.

Adult↗
PubMed2000

Ventilatory constraints during exercise in patients with chronic heart failure.

We examined the degree of ventilatory constraint in patients with a history of chronic heart failure (CHF; n = 11; mean +/- SE age, 62 +/- 4 years; cardiac index [CI], 2.0 +/- 0.1; and ejection fraction [EF], 24 +/- 2%) and in control subjects (CTLS; n = 8; age, 61 +/- 5 years; CI, 2.6 +/- 0.3) by plotting the tidal flow-volume responses to graded exercise in relationship to the maximal flow-volume envelope (MFVL). Inspiratory capacity (IC) maneuvers were performed to follow changes in end-expiratory lung volume (EELV) during exercise, and the degree of expiratory flow limitation was assessed as the percent of the tidal volume (VT) that met or exceeded the expiratory boundary of the MFVL. CHF patients had significantly (p < 0.05) reduced baseline pulmonary function (FVC, 76 +/- 4%; FEV(1), 78 +/- 4% predicted) relative to CTLS (FVC, 99 +/- 4%; FEV(1), 102 +/- 4% predicted). At peak exercise, oxygen consumption (VO(2)) and minute ventilation (V(E)) were lower in CHF patients than in CTLS (VO(2), 17 +/- 2 vs 32 +/- 2 mL/kg/min; VE, 56 +/- 4 vs 82 +/- 6 L/min, respectively), whereas VE/carbon dioxide output was higher (42 +/- 4 vs 29 +/- 5). In CTLS, EELV initially decreased with light exercise, but increased as VE and expiratory flow limitation increased. In contrast, the EELV in patients with CHF remained near residual volume (RV) throughout exercise, despite increasing flow limitation. At peak exercise, IC averaged 91 +/- 3% and 79 +/- 4% (p < 0.05) of the FVC in CHF patients and CTLS, respectively, and flow limitation was present over > 45% of the VT in CHF patients vs < 25% in CTLS (despite the higher VE in CTLS). The least fit and most symptomatic CHF patients demonstrated the lowest EELV, the greatest degree of flow limitation, and a limited response to increased inspired carbon dioxide during exercise, all consistent with VE constraint. We conclude that patients with CHF commonly breathe near RV during exertion and experience expiratory flow limitation. This results in VE constraint and may contribute to exertional intolerance.

Adult↗
PubMed2001

The efficacy of postoperative incentive spirometry is influenced by the device-specific imposed work of breathing.

STUDY OBJECTIVES: The study evaluated the impact of the additional imposed work of breathing (WBimp) generated by two different spirometers on postoperative incentive spirometry performance in patients at high risk and moderate risk for postoperative pulmonary complications (PPCs). Additionally, we investigated whether maximal inspiratory pressure (PImax) is an easy estimate of the WBimp imposed by incentive spirometers. DESIGN: Prospective, randomized, single-blind clinical trial. SETTING: ICU of a university hospital. INTERVENTIONS AND MEASUREMENTS: Thirty male patients were assigned to a group at high risk for PPCs (group A; inspiratory capacity [IC], < 1.6 L) or to a group at moderate risk for PPCs (group B; IC, 1.6 to 2.5 L) after upper-abdominal, thoracic, or two-cavity surgery. On the first or second postoperative day WBimp, IC, and PImax were recorded without spirometers (baseline) and during incentive spirometry with the Mediflo spirometer (Medimex; Hamburg, Germany) (high WBimp) and the Coach spirometer (Kendall; Neustadt, Germany) (low WBimp) using a pneumotachograph. In group A, the baseline and the ICs for both spirometers only differed slightly. In group B, the IC was significantly reduced for the Mediflo (p < 0.05), which imposed a WBimp twice as high as the Coach (p < 0.01). PImax was significantly increased for both the Mediflo and the Coach (p < 0.01). PImax was positively correlated with WBimp (r = 0.8). CONCLUSIONS: Incentive spirometers differ considerably in their additional Wbimp with a potential impact on the efficacy of postoperative incentive spirometry performance. PImax might be an easy clinical estimate for the WBimp during incentive spirometry. Incentive spirometers with low WBimp permit increased maximal sustained inspiration and, thus, enhanced incentive spirometry performance, and, therefore, it might be more suitable for use in postoperative respiratory care.

Humans↗
PubMed2002

Response of lung volumes to inhaled salbutamol in a large population of patients with severe hyperinflation.

OBJECTIVES: Current criteria use FEV(1) to assess bronchodilator responsiveness, despite its insensitivity and inability to predict improvement in symptoms or exercise tolerance. Response in lung volumes remains largely unexplored even though volume parameters, such as inspiratory capacity (IC), closely correlate with functional improvements. Therefore, we assessed the response of lung volumes (i.e., by IC, total lung capacity [TLC], functional residual capacity [FRC], residual volume [RV], and FVC) to salbutamol and the relationship of these changes to improvements in the spirometry in these patients. DESIGN: A retrospective review of data extracted from a large database of patients who were undergoing spirometry and static lung volume measurements before and after the administration of 200 microg salbutamol. PATIENTS: Patients with an FEV(1)/FVC ratio of < 85% of predicted values were defined as being severely hyperinflated (SH) if TLC was > 133% of predicted and as being moderately hyperinflated (MH) if TLC was 115 to 133% of predicted. RESULTS: Two hundred eighty-one SH patients and 676 MH patients were identified. Salbutamol significantly reduced the mean (+/- SEM) TLC (SH patients, 222 +/- 23 mL; MH patients, 150 +/- 10 mL; p < 0.001), FRC (SH patients, 442 +/- 26 mL; MH patients, 260 +/- 39 mL; p < 0.001), and RV (SH patients, 510 +/- 28 mL; MH patients, 300 +/- 14 mL; p < 0.001) and increased both the IC (SH patients, 220 +/- 15 mL; MH patients, 110 +/- 11 mL; p < 0.001) and FVC (SH patients, 336 +/- 21 mL; MH patients, 204 +/- 13 mL; p < 0.001). FEV(1) improved in a minority of patients (SH patients, 33%; MH patients, 26%), but if lung volume measurements are also considered, the overall bronchodilator response may improve to up to 76% of the SH group and up to 62% of the MH group. Changes in volumes correlated poorly with changes in maximal airflows. CONCLUSIONS: Bronchodilators reduce hyperinflation. Measurements of lung volumes before and after bronchodilators add sensitivity when examining for bronchodilator responsiveness.

Aged↗
PubMed2005

Expiratory flow limitation is associated with orthopnea and reversed by vasodilators and diuretics in left heart failure.

BACKGROUND: In patients with acute left heart failure (LHF), orthopnea has also been related to the occurrence or worsening of expiratory flow limitation (EFL) in the supine position. We wished to assess whether short-term treatment with vasodilators and diuretics was able to abolish supine EFL and whether this could help to control orthopnea in patients with acute LHF. METHODS: In nine nonobese (ie, mean [+/- SD] body mass index, 24 +/- 5 kg/m2), never-smoker patients (two men and seven women; mean age, 77 +/- 7 years) with acute LHF (mean ejection fraction, 43 +/- 15%), we assessed EFL by the negative expiratory pressure method and dyspnea by the Borg scale, with patients in both the seated and supine positions, before and after short-term treatment with vasodilators and diuretics until hospital discharge. Orthopnea was defined as a positive difference in the Borg score between measurements made with the patient in the supine and seated positions. Postural variations in the end-expiratory lung volume were inferred from changes in inspiratory capacity (IC) that were measured under the same circumstances. RESULTS: Before treatment, with the patient in the seated position the mean dyspnea score was 1.5 +/- 0.5, the mean IC was 1.49 +/- 0.38 L, seven patients were non-flow-limited, and two patients were flow-limited. During recumbency, the mean dyspnea score was 2.7 +/- 0.5 (p < 0.01 vs seated position values), the mean IC was 1.66 +/- 0.45 L, and seven patients exhibited EFL. After a mean duration of 17 +/- 8 days of treatment (range, 7 to 28 days), EFL was detected in two patients only in the supine position, IC increased both in the seated position (1.65 +/- 0.34 L; p < 0.01) and the supine position (1.81 +/- 0.41 L; p = 0.07) position, and, although only two patients denied orthopnea, the mean dyspnea score during recumbency actually decreased to 1.9 +/- 1.0 (p < 0.05). CONCLUSIONS: Our results indicate that short-term treatment with vasodilators and diuretics is able to control orthopnea and to remove supine EFL in most patients with acute LHF, suggesting a posture-related increase in bronchial obstruction as the main mechanism of EFL, which appears to play a role in the occurrence and severity of orthopnea in these circumstances.

Aged↗
PubMed2005

Arm exercise and hyperinflation in patients with COPD: effect of arm training.

BACKGROUND: Unlike studies on leg exercise, reports on the regulation of dynamic hyperinflation during arm exercise are scanty. We ascertained the following in patients with COPD: (1) whether and to what extent upper-limb exercise results in dynamic hyperinflation, and (2) the mechanism whereby an arm-training program (ATP) reduces arm effort and dyspnea. PATIENTS: Twelve patients with moderate-to-severe COPD were tested during incremental, symptom-limited arm exercise after a non-intervention control period (pre-ATP) and after ATP. METHODS: Exercise testing (1-min increments of 5 W) was performed using an arm ergometer. Oxygen uptake (V(O2)), carbon dioxide output, minute ventilation (Ve), tidal volume, and respiratory rate (RR) were measured continuously during the tests. Inspiratory capacity (IC), exercise dyspnea, and arm effort using a Borg scale were assessed at each step of exercise. RESULTS: Arm exercise resulted in a significant decrease in IC and significant positive relationships of IC with an increase in V(O2) and exercise dyspnea and arm effort. The results of ATP were as follows: (1) a significant increase in exercise capacity (p < 0.001); (2) no change in the relationships of exercise dyspnea and arm effort with Ve and IC, and of IC with V(O2); (3) at a standardized work rate, Ve, exercise dyspnea, and arm effort significantly decreased, while the decrease in IC was significantly less (p < 0.01) than before the ATP; the decrease in Ve was accomplished primarily by a decrease in RR; and (4) at standardized Ve, exercise dyspnea and arm effort decreased significantly. CONCLUSIONS: Arm exercise results in the association of dynamic hyperinflation, exercise dyspnea, and arm effort in COPD patients. An ATP increases arm endurance, modulates dynamic hyperinflation, and reduces symptoms.

Aged↗