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.

Lack of additional effect of adjunct of assisted ventilation to pulmonary rehabilitation in mild COPD patients.

Different modalities of assisted ventilation improve breathlessness and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the effects of the addition of assisted ventilation during exercise training on the outcome of a structured pulmonary rehabilitation programme (PRP) in COPD patients. Thirty-three male patients with stable COPD (mean (SD) forced expiratory volume in 1 s (FEV1) 44 (16) % pred), without chronic ventilatory failure, undergoing a 6-week multidisciplinary outpatient PRP including exercise training, were randomised to training during either mask proportional assist ventilation (PAV: 18 patients) or spontaneous breathing (SB: 15 patients). Assessment included exercise tolerance, dyspnoea, leg fatigue, and health-related quality of life (HRQL). Five out of 18 patients (28%) in the PAV group dropped out due to lack of compliance with the equipment. Both groups showed significant post-PRP improvements in exercise tolerance (peak work rate difference: 20 (95% Cl 2.4-37.6) and 14 (3.8% CI to 24.2) W in PAV and SB group, respectively), dyspnoea and leg fatigue, but not in HRQL, without any significant difference between groups. It is concluded that with the modality and in the patients assessed in this study assisted ventilation during training sessions included in a multidisciplinary PRP was not well tolerated by all patients and gave no additional physiological benefit in comparison with exercise training alone.

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.

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.

Is it really useful to repeat outpatient pulmonary rehabilitation programs in patients with chronic airway obstruction? A 2-year controlled study.

STUDY OBJECTIVES: To answer the following questions: in patients with chronic airway obstruction (CAO), (1) can pulmonary rehabilitation lead to similar short-term gains at successive, yearly interventions, and (2) is there any real clinical or physiologic long-term benefit by yearly repetition of pulmonary rehabilitation programs (PRPs)? DESIGN: Randomized, controlled clinical study. SETTING: Pulmonary rehabilitation center. PATIENTS: Sixty-one CAO patients studied 1 year after completing an initial 8-week outpatient PRP (PRP1). INTERVENTION: Patients were randomly classified into two groups. A second PRP (PRP2) was completed by the first group (group 1) but not by the second group (group 2). One year later, a third PRP (PRP3) was performed by both groups. MEASUREMENTS: Lung function, cycloergometry, walking test, dyspnea, and health-related quality of life (HRQL) were assessed before and after PRP2, and before and after PRP3. The numbers of hospitalizations and exacerbations over the year were also recorded. RESULTS: Complete data sets were obtained from 36 patients (17 patients in group 1 and 19 patients in group 2). The two groups did not differ in any parameter either before PRP1, after PRP1, or at randomization. There was no significant change over time for airway obstruction in either group. After PRP2, exercise tolerance, dyspnea, and HRQL improved in group 1. Nevertheless, 1 year later, patients of group 1 did not differ from patients of group 2 in any outcome parameter, such that in comparison to before PRP1, only HRQL was still better in both groups 24 months after PRP1. Yearly hospitalizations and exacerbations per patient significantly decreased in both groups in the 2 years following PRP1, when compared to the 2 years prior. Nevertheless, at the 24-month follow-up visit, a further reduction in yearly exacerbations was observed only in group 1 but not in group 2 in comparison to what was observed at the 12-month follow-up visit. The PRP3 resulted in improvement in exercise tolerance in both groups. CONCLUSION: In patients with CAO, an outpatient PRP can achieve benefits in HRQL and a decreased number of hospitalizations, which persist for a period of 2 years. Successive, yearly interventions lead to similar short-term gains but do not result in additive long-term physiologic benefits. Further reduction in yearly exacerbations seems to be the main benefit of an additional PRP.

Relevance of dyspnoea and respiratory function measurements in monitoring of asthma: a factor analysis.

Previous studies in patients with stable chronic obstructive pulmonary disease have demonstrated that objective measures (lung volumes and respiratory muscle force) and clinical or subjective measures (symptoms of breathlessness and exercise tolerance) are quantities that independently characterize the conditions of these patients. Such an evaluation has not been previously applied in patients with stable bronchial asthma. Sixty-nine patients with stable chronic asthma underwent evaluation of static (functional residual capacity, FRC) and dynamic [forced expiratory volume in 1 sec (FEV1) and forced vital capacity, FVC] lung volumes; respiratory muscle strength (RMS), by measuring maximal inspiratory and expiratory pressures, and exercise capacity by means of the 6-min walking distance (6MWD). Chronic exertional dyspnoea was assessed by the Baseline Dyspnoea Index (BDI) focal score and by the Medical Research Council (MRC) scale. Statistical evaluation was performed by applying factor analysis. Three factors accounted for 78% of the total variance in the data: FEV1, FVC loaded on a factor I; RMS, FRC and 6MWD loaded on a factor II; dyspnoea ratings loaded on a factor III. Post-hoc analysis by randomly dividing the patients into two subgroups gave the same results. In asthmatic patients, airway obstruction appeared as an independent dimension or factor. Dyspnoea independently characterized the condition of asthma. Submaximal exercise tolerance could not be associated with the symptom of breathlessness. Evidence of independent factors support the validity of routine, multi-factorial assessment and the primary goal of treatment to alleviate symptoms and improve functional capacity in stable asthmatics.

Physiological and symptom determinants of exercise performance in patients with chronic airway obstruction.

To evaluate the physiological and symptom determinants of exercise performance (EP) as measured by a 6-min walking test (6MWD), Watt(max), and peak oxygen consumption (VO2 ml/min/kg), 105 patients with chronic airway obstruction (CAO) [50 chronic obstructive pulmonary disease (COPD): 44 men, aged 63+/-7 years, forced expiratory volume in 1 sec (FEV1) forced vital capacity (FVC)(-1)% 54+/-13; and 55 asthmatic: 23 men, aged 55+/-10 years, FEV1 FVC(-1) % 65+/-10] underwent evaluation of 6MWD, symptom limited cyclo-ergometer exercise test, spirometry, respiratory muscle function, arterial blood gases and sensation of dyspnoea [using the Borg scale, Visual Analogue Scale (VAS) and Baseline Dyspnoea Index (BDI)]. A hierarchical method of analysis identified the residual volume (RV), total lung capacity (TLC)(-1) ratio, BDI and the patient's age as the strongest and most consistent correlates of EP (r2 = 0.14-0.21). The correlation between EP and its various determinants was not influenced by diagnosis. The relationship between breathlessness and EP was different between men and women: at any given level of exercise, women were more breathless than men. In multivariate analyses that contained both RV TLC(-1) and BDI, the RV TLC(-1) ratio was the strongest correlate of EP, although the BDI remained a significant covariate. Overall, age was the major determinant of EP but inclusion of the RV TLC(-1) ratio and the BDI into the model explained a further 9-15% of the variance in EP. These three covariates together explained 26-34% of the variance between patients. We conclude that in stable CAO patients, the prediction of exercise capacity by anthropometric, demographic, clinical and physiological variables is likely to be low. Age, pulmonary hyperinflation and dyspnoea are the strongest and most consistent correlates of impaired exercise performance. Airways obstruction, measured during expiration using FEV1, does not appear to be a predictor of physiological impairment. These results underline the importance of performing exercise evaluation in CAO 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.

Long-term effectiveness of pulmonary rehabilitation in patients with chronic airway obstruction.

The aim of this study was to evaluate the long-term outcome of an outpatient pulmonary rehabilitation programme (PRP) in patients with chronic airway obstruction (CAO). In 61 CAO patients (35 asthmatics and 26 chronic obstructive pulmonary disease (COPD)) lung and respiratory muscle function, exercise tolerance (by symptom limited cycloergometer and walking tests), dyspnoea (Borg scale, visual analogue scale (VAS), baseline and transitional dyspnoea index (BDI and TDI, respectively)) and quality of life (St George's Respiratory Questionnaire (SGRQ)) were assessed at baseline (to), at discharge (t1) and 12 months postdischarge (t2). Preprogramme and post-programme hospital admissions and exacerbations of disease were also recorded. In comparison with baseline, no significant change was observed in lung function tests in either diagnostic group, either at t1 or at t2. In both groups improvements in respiratory muscle strength, exercise tolerance, Borg scale and VAS reported at t1 were partially reduced at t2. Analysis of variance showed that these changes over time were similar in the two groups. Mean values of SGRQ and BDI/TDI improved at t1, and, unlike exercise tolerance, did not worsen at t2. However, a clinically relevant difference in SGRQ between t2 and to was reported only in 56% of asthmatics and 52% of COPD patients. Compared with the preceding 2 yrs, in the year following PRP, hospital admissions and disease exacerbations decreased significantly in both diagnostic groups. Regardless of diagnosis, patients with chronic airway obstruction who underwent an outpatient pulmonary rehabilitation programme maintained an improved quality of life 12 months postdischarge despite a partial loss of the improvement in exercise tolerance.

Effects of proportional assist ventilation on exercise tolerance in COPD patients with chronic hypercapnia.

This study investigates the impact of proportional assist ventilation (PAV), a new mode of partial ventilatory support, on exercise tolerance and breathlessness in severe hypercapnic chronic obstructive pulmonary disease (COPD) patients. We also examined the effects of continuous positive airway pressure (CPAP) and pressure support ventilation (PSV). On two consecutive days, 15 stable hypercapnic COPD patients underwent four endurance tests on a cycle ergometer at 80% of their maximal workrate, receiving, via a nasal mask in random order, either: 1) sham ventilation (CPAP: 1 cmH2O); 2) CPAP (6 cmH2O); 3) PSV (inspiratory pressure support: 12-16 cmH2O; expiratory positive airway pressure (EPAP): 1 cmH2O); or 4) PAV (8.6+/-3.6 cmH2O x L(-1) and 3+/-1.3 cmH2O x L(-1)x s(-1) of volume and flow assistance, respectively plus EPAP: 1 cmH2O). Oxygen supply was standardized to maintain an arterial oxygen saturation (Sa,O2) of 92-93%. Breathing pattern and minute ventilation (by respiratory inductive plethysmography), pulse oximetry, end tidal partial pressure of CO2, cardiac frequency and sensations of dyspnoea and leg discomfort (by Borg scale) were monitored. In comparison to sham ventilation, PAV, PSV and CPAP were able to increase the endurance time (from 7.2+/-4.4 to 12+/-5.6, 10+/-5.2 and 9.6+/-4.6 min, respectively) and to reduce dyspnoea and oxygen flow to the nasal mask. However, the greatest improvement was observed with PAV. We conclude that PAV delivered by nasal mask can im-prove exercise tolerance and dyspnoea in stable hypercapnic COPD patients and hence this mode of ventilatory support may be useful in respiratory rehabilitation programmes.

Effects of body position on the carbon monoxide diffusing capacity in patients with chronic heart failure: relation to hemodynamic changes.

OBJECTIVE: Pulmonary diffusion has been found to be reduced in patients with congestive heart failure. The effects of postural changes on the diffusing capacity had been evaluated in healthy subjects, but not in patients with heart failure. The aim of this study was to evaluate the posture-induced changes in diffusing capacity in patients with chronic heart failure and their relation to the hemodynamic profile. METHODS: The pulmonary carbon monoxide diffusing capacity (DLCO) was measured in the supine position, with 20 degrees passive head elevation, and in the sitting position, both postures maintained for 10 min, in a group of 32 male patients with mild to moderate chronic heart failure due to left ventricular systolic dysfunction (ejection fraction <35%). On a separate day, in the absence of any changes in clinical status and therapy, the hemodynamic parameters were measured by right-heart catheterization. The sequence of postures was assigned randomly. RESULTS: The mean values of DLCO were slightly reduced and did not differ in the two positions (20.3 +/- 5.7 vs. 19.4 +/- 5.6 ml/min/mm Hg, 77 +/- 23 vs. 75 +/- 20% of predicted, respectively). The patients were then subdivided according to changes in DLCO from the supine to the sitting position: DLCO increased (+23%) in 9 patients (28%, group 1), decreased (-17.5%) in 17 patients (53%, group 2), and remained within the coefficient of reproducibility ( +/- 5 %) in 6 patients (group 3). As compared with group 2, group 1 patients showed a significant increase in mean pulmonary artery pressure (+7 vs. -15%, p < 0.01) and pulmonary capillary wedge pressure (+8 vs. -22%, p < 0.005) from the supine to the sitting position, while the cardiac index showed a smaller - but not significant - decrease in group 1 (-5 vs. -12%). The percent changes in DLCO significantly correlated with changes in pulmonary capillary wedge (r = 0.54, p < 0.0005) and mean pulmonary artery (r = 0.47, p < 0.005) pressures. CONCLUSIONS: In chronic heart failure postural changes may induce different responses in diffusing capacity. To a greater extent than in healthy subjects, the most common response is a decrease in DLCO in the sitting as compared with the supine position. The DLCO changes correlate with variations in pulmonary circulation pressure, probably due to changes in pulmonary vascular recruitment and pulmonary capillary blood volume.

Short-term effects of nasal proportional assist ventilation in patients with chronic hypercapnic respiratory insufficiency.

Proportional assist ventilation (PAV) has recently been proposed as a mode of synchronized partial ventilatory support. This study evaluates the short-term effects of nasal PAV on arterial blood gases in stable patients with chronic hypercapnia. Forty two patients (30 with chronic obstructive pulmonary disease (COPD) and 12 with restrictive chest wall disease (RCWD) due to kyphoscoliosis) underwent a 1 h run of nasal PAV. Randomly, two levels of assistance were performed: 1) PAV was set at a level corresponding to volume assist (VA) and flow assist (FA) at 80% of the individual values of elastance (Ers) and resistance (Rrs) obtained with the "runaway" method; and 2) VA and FA were set at a value corresponding to the difference between the patients' individual Ers and Rrs and normal values of Ers and Rrs. Arterial blood gases and dyspnoea (by visual analogue scale (VAS)) were evaluated in all patients during unsupported ventilation and 60 min of PAV. PAV was well tolerated and resulted in significant improvement in arterial oxygen tension (Pa,O2), arterial carbon dioxide tension (Pa,CO2) (6.8+/-0.8 to 7.4+/-1.4 and 7.2/-0.9 to 6.8+/-0.9 kPa, respectively) and VAS (29+/-23 to 20+/-18%). The effects of PAV were not different in the two groups of diseases nor in the two groups of settings. Different settings of nasal proportional assist ventilation are well tolerated and may improve gas exchange and dyspnoea in patients with stable hypercapnic respiratory insufficiency.

Long-term home care programmes may reduce hospital admissions in COPD with chronic hypercapnia.

Long-term oxygen therapy (LTOT) has been shown to improve survival in chronic obstructive pulmonary disease (COPD) patients. The clinical effectiveness of long-term home mechanical ventilation (HMV) is still discussed, nevertheless both LTOT and HMV are often included in the home care programmes of these patients. To evaluate the effectiveness of home care programmes including either HMV or LTOT, 34 COPD patients were studied. They were admitted to either HMV (Group A: 12 males and 5 females, aged 62 +/- 5 yrs), or LTOT (Group B: 9 males and 8 females, aged 62 +/- 8 yrs). They were compared to a historical group (Group C: 19 males and 10 females, aged 67 +/- 16 yrs) performing only their usual standard LTOT during the same period. Spirometry, maximal inspiratory pressure and arterial blood gas values were assessed at baseline and at 6, 12 and 18 months of follow-up. Mortality rate and number of hospital and intensive care unit (ICU) admissions and days of hospitalization were also assessed. Four out of 17 (23%) patients in Group A, 3 out of 17 (18%) in Group B, and 5 out of 29 (17%) in Group C died within 18 months. Of the lung function tests, only maximal inspiratory pressure in Group A showed a significant increase in the 18th month (50 +/- 4 to 56 +/- 7 cmH2O; p<0.01). In comparison to 18 months prior to the study, hospital admissions (from 2.2 +/- 0.6 to 1.3 +/- 1.1 and from 2.0 +/- 0.7 to 1.0 +/- 0.9 for Group A and B, respectively; p<0.005 for both), and days of hospitalization (from 60 +/- 34 to 34 +/- 40 and from 55 +/- 23 to 18 +/- 20 days in Group A and B, respectively; p<0.005 for both) significantly decreased only in the two groups submitted to the home care programme. We conclude that home care programmes may be effective in the long-term treatment of chronically hypercapnic chronic obstructive pulmonary disease patients in reducing hospital admissions.

Acute exacerbations in patients with COPD: predictors of need for mechanical ventilation.

Predictive factors in mechanically-ventilated patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) have been extensively studied but not in spontaneously breathing patients. The aim of this retrospective study was to evaluate the contribution of parameters of respiratory mechanics, clinical and nutritional status in predicting the need for mechanical ventilation (MV) in COPD patients treated with medical therapy for an acute exacerbation. Anthropometric data, Acute Physiology and Chronic Health Evaluation (APACHE) II score, bedside spirometry, breathing pattern, respiratory mechanics and blood gases were measured in 39 COPD patients upon hospital admission for exacerbation of their disease. Fourteen patients in whom MV was necessary were compared with 25 patients in whom medical therapy was enough for a good outcome. The discriminant analysis showed, with decreasing order of power, that nutritional prognostic index (NPI), APACHE II score, forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio, vital capacity (VC) (% predicted) and FVC (% pred) provided a significant distinction between the two groups. The discriminant equation considering NPI, and FVC (% pred) could correctly predict the success in 76% of the patients. A multiparametric stepwise regression analysis showed that APACHE II score was significantly correlated with NPI, VC (% pred), pressure time index (PTI) and duty cycle, i.e. fraction of inspiration to duration of total breathing cycle (tl/ttot). In conclusion, underlying general conditions as assessed by malnutrition and APACHE II score were shown to be unfavourable indices of outcome for chronic obstructive pulmonary disease patients who experienced an exacerbation of their disease and were treated with medical therapy. Flow limitation data as assessed by the forced expiratory manoeuvre may provide additional information.

Methacholine inhaled challenge: study of correlation among different indices expressing the result.

We tested measures of specific airway conductance (sGaw) and forced expiratory volume in one second (FEV1) versus transcutaneous oxygen tension (Ptc,O2) during inhaled methacholine bronchial challenge in 60 out-patients (38 males 22 females, mean age 33 +/- 13 yrs). The provocative doses of methacholine needed to produce a 35% decrease of sGaw (PD35,sGaw), a 20% fall in FEV1 (PD20,FEV1) and a 20% decrease in Ptc,O2 (PD20,O2) were simultaneously derived from the dose-response curves. Two groups were identified according to the PD20,FEV1 result ("responders" with a PD20,FEV1 < 2,000 micrograms methacholine and "nonresponders" with PD20,FEV1 > 2,000 micrograms methacholine). All three indices derived from the dose-response curves differed significantly between the groups (p < 0.00005). The relationship analysis showed a significantly better value for PD20,O2 versus PD35,sGaw (r = 0.98) than versus PD20, FEV1 (r = 0.62). We observed similar baseline levels and variations in arterial oxygen tension (Pa,O2) and Ptc,O2 during methacholine challenge (-25 and -27%, respectively) in 14 randomly studied responders. Thus, inhaled methacholine-induced hypoxaemia (PD20,O2) seems to reflect PD35,sGaw better than changes in FEV1. Our investigation supports the hypothesis that PD20,O2 could be useful in interpreting the methacholine inhaled challenge. It could be of help in clarifying the pathophysiological meaning of the concurrent hypoxaemia during this challenge, which should be further elucidated.

Non-invasive mechanical ventilation in severe chronic obstructive lung disease and acute respiratory failure: short- and long-term prognosis.

OBJECTIVE: To evaluate the short- and long-term prognosis of patients with chronic obstructive lung disease (COLD) who had noninvasive mechanical ventilation (NMV) for acute respiratory failure (ARF). DESIGN: Retrospective study. SETTING: Two respiratory intermediate intensive care units. PATIENTS: Two groups of patients suffering from COLD and an ARF episode requiring mechanical ventilation. Group 1 (30 patients) was given NMV using face masks (aged 64 +/- 9 years; pH = 7.28 +/- 0.05; PaCO2 = 83 +/- 18 mmHg; PaO2/FIO2 = 141 +/- 61). Group 2 (27 patients) was composed of control patients (aged = 65 +/- 8 years; pH = 7.26 +/- 0.05; PaCO2 = 75 +/- 17 mmHg; PaO2/FIO2 = 167 +/- 41) given MV using endotracheal intubation (EI) when clinical and functional conditions had further deteriorated because the medical therapy failed and NMV was not available at the time. Causes of ARF were in group 1 and 2 respectively: pneumonia in 8 (27%) and 11 (41%), acute exacerbation of COLD in 19 (63%) and 14 (52%) and pulmonary embolism in 3 (10%) and 2 (7%) patients. MEASUREMENTS AND RESULTS: Success rate, mortality during stay in ICU (at 3 months and at 1 year), and the need for rehospitalization during the year following ARF were measured in this study. Group 1 showed a success rate of 74%, only 8/30 patients needing EI and conventional MV. In group 2, the weaning success was 74% (20/27 patients). The mortality for group 1 was 20% in IICU, 23% at 3 months and 30% at 1 year; and 26% for group 2 in ICU, 48% at 3 months and 63% at 1 year. Within each group 1-year mortality was greater (p < 0.01) in patients with pneumonia. The number of new ICU admissions during the follow-up at 1 year was 0.12 versus 0.30 in groups 1 and 2 respectively (p < 0.05). CONCLUSION: For patients suffering from COLD who have undergone ARF, avoiding EI by early treatment with NMV is associated with better survival in comparison to patients bound to invasive MV. Pneumonia as a cause of ARF may worsen the prognosis in both groups of patients.

Non-invasive mechanical ventilation in acute respiratory failure due to chronic obstructive pulmonary disease: correlates for success.

BACKGROUND: Non-invasive mechanical ventilation is increasingly used in the treatment of acute respiratory failure in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to identify simple parameters to predict the success of this technique. METHODS: Fifty nine episodes of acute respiratory failure in 47 patients with COPD treated with non-invasive mechanical ventilation were analysed, considering each one as successful (78%) or unsuccessful (22%) according to survival and to the need for endotracheal intubation. RESULTS: Pneumonia was the cause of acute respiratory failure in 38% of the unsuccessful episodes but only in 9% of the successful ones. Success with non-invasive mechanical ventilation was associated with less severely abnormal baseline clinical and functional parameters, and with less severe levels of acidosis assessed during an initial trial of non-invasive mechanical ventilation. CONCLUSIONS: The severity of the episode of acute respiratory failure as assessed by clinical and functional compromise, and the level of acidosis and hypercapnia during an initial trial of non-invasive mechanical ventilation, have an influence on the likelihood for success with non-invasive mechanical ventilation and may prove to be useful in deciding whether to continue with this treatment.

Professional figures in intermediate intensive units.

In Italy, respiratory intermediate intensive care units (IICUs) are not yet considered as autonomous hospital departments. The IICU of the Rehabilitation Department of the Medical Centre of Gussago (12 monitored beds) provides care for respiratory and cardiac patients. Ventilatory assistance and noninvasive modalities both in treatment and monitoring suggest a multidisciplinary approach to the patient. Highly professional figures should, therefore, be singled out to provide care in a respiratory IICU. The medical staff is composed of one anaesthesiologist, one cardiologist and one pulmonologist, who can integrate care when respiratory complications occur in a cardiological patient, or when cardiac events affect a respiratory patient. Nurses are capable of specific activities, especially when ventilatory assistance is required. The presence of a physiotherapist reduces the nursing workload, especially for ventilated individuals. The psychological aspect is undertaken by a specialist. Finally, an expert in nutrition provides an individualized dietary regimen. Our 4 year experience encourages such a multidisciplinary approach. An ideal integration of the professional activities should provide adequate and individual care for patients admitted to an IICU.