Strategies to relieve dyspnoea in patients with advanced chronic respiratory diseases. A narrative review.

BACKGROUND AND OBJECTIVE: The management of symptoms in patients with advanced chronic respiratory diseases needs more attention. This review summarizes the latest evidence on interventions to relieve dyspnoea in these patients. METHODS: We searched randomised controlled trials, observational studies, systematic reviews, and meta-analyses published between 1990 and 2019 in English in PubMed data base using the keywords. Dyspnoea, Breathlessness AND: pharmacological and non pharmacological therapy, oxygen, non invasive ventilation, pulmonary rehabilitation, alternative medicine, intensive care, palliative care, integrated care, self-management. Studies on drugs (e.g. bronchodilators) or interventions (e.g. lung volume reduction surgery, lung transplantation) to manage underlying conditions and complications, or tools for relief of associated symptoms such as pain, are not addressed. RESULTS: Relief of dyspnoea has received relatively little attention in clinical practice and literature. Many pharmacological and non pharmacological therapies are available to relieve dyspnoea, and improve patients' quality of life. There is a need for greater knowledge of the benefits and risks of these tools by doctors, patients and families to avoid unnecessary fears which might reduce or delay the delivery of appropriate care. We need services for multidisciplinary care in early and late phases of diseases. Early integration of palliative care with respiratory, primary care, and rehabilitation services can help patients and caregivers. CONCLUSION: Relief of dyspnoea as well as of any distressing symptom is a human right and an ethical duty for doctors and caregivers who have many potential resources to achieve this.

Changes of swallowing function after tracheostomy: a videofluoroscopy study.

BACKGROUND: Patients after tracheostomy often present swallowing dysfunctions but little is known about the mechanism underlying dysphagia and its reversibility. The aims of this study were: 1) to characterize swallowing dysfunctions in patients with dysphagia and tracheostomy; 2) to evaluate the reversibility of these changes; 3) to evaluate the possible influence of the underlying disease. METHODS: Prospective, observational, single-center study enrolling patients with tracheostomy admitted to a rehabilitation center over a period of 36 months. All patients who were found to be dysphagic underwent a swallowing study with videofluoroscopy (VF) at the beginning of hospital stay and a second VF study was repeated after approximately 4 weeks. RESULTS: A total of 557 patients with tracheostomy were admitted to the rehabilitation center during the considered period. 187 patients fulfilled the enrolling criteria and were studied with VF soon after admission. They had been tracheostomized for respiratory failure secondary to cerebrovascular accident (N.=106) or to acute-on chronic respiratory failure (N.=81). Incomplete backward epiglottis folding, pharyngeal retention, penetration and aspiration were the most frequent swallowing dysfunctions, observed with a frequency of 48%, 32%, 33% and 28%, respectively. Eighty-one patients underwent a second VF study, where these four swallowing phases again turned out to be the most compromised, with a frequency of 41%, 19%, 27% and 17%, respectively. The improvement was less evident in patients with chronic respiratory disease. CONCLUSION: The swallowing function is impaired in patients with dysphagia and tracheostomy, but most swallowing abnormalities appear to be partially reversible. Patients with chronic respiratory disease exhibit a worse swallowing function.

Tele-assistance in chronic respiratory failure patients: a randomised clinical trial.

Chronic respiratory patients requiring oxygen or home mechanical ventilation experience frequent exacerbations and hospitalisations with related costs. Strict monitoring and care have been recommended. The aim of the present study was to primarily evaluate reduction in hospitalisations and, secondly, exacerbations, general practitioner (GP) calls and related cost-effectiveness of tele-assistance (TA) for these patients. A total of 240 patients (101 with chronic obstructive pulmonary disease (COPD)) were randomised to two groups: an intervention group entered a 1-yr TA programme while controls received traditional care. No anthropometric and clinical differences were found between groups both in baseline and in mortality (18% for TA, 23% for controls). Compared with controls, the TA group experienced significantly fewer hospitalisations (-36%), urgent GP calls (-65%) and acute exacerbations (-71%). Only COPD patients, as a separate group, had fewer hospitalisations, emergency room admissions, urgent GP calls or exacerbations. Each patient referred to staff a mean+/-sd 36+/-25 times. After deduction of TA costs, the average overall cost for each patient was 33% less than that for usual care. In chronic respiratory failure patients on oxygen or home mechanical ventilation, a nurse-centred tele-assistance prevents hospitalisations while it is cost-effective. The chronic obstructive pulmonary disease group seems to have a greater advantage from tele-assistance.

Efficacy of pulmonary rehabilitation in chronic respiratory failure (CRF) due to chronic obstructive pulmonary disease (COPD): The Maugeri Study.

UNLABELLED: While the effectiveness of pulmonary rehabilitation (PR) in chronic obstructive pulmonary disease (COPD) is well established, its effectiveness in the most severe category of COPD, i.e. patients with chronic respiratory failure (CRF), is less well known. OBJECTIVE: To verify the effects of PR in patients with CRF, and compare the level of improvement with PR in these patients to that of COPDs not affected by CRF. METHODS: A multi-centre study was carried out on COPD patients with versus without CRF. The PR program included educational support, exercise training, and nutritional and psychological counselling. Lung function, arterial gases, walk test (6MWT), dyspnoea (MRC; BDI/TDI), and quality of life (MRF(28); SGRQ) were evaluated. RESULTS: Thousand forty seven consecutive COPD inpatients (327 with CRF) were evaluated. In patients with CRF all parameters improved after PR (0.001). Mean changes: FEV(1), 112 ml; PaO(2), 3.0 mmHg; PaCO(2), 3.3 mmHg; 6MWT, 48 m; MRC, 0.85 units; MRF(28) total score, 11.5 units. These changes were similar to those observed in patients without CRF. CONCLUSIONS: This study, featuring the largest cohort so far reported in the literature, shows that PR is equally effective in the more severe COPD patients, i.e. those with CRF, and supports the prescription of PR also in these patients.

Nutritional status and airflow obstruction: two independent contributors to CO diffusing capacity impairment in COPD.

BACKGROUND: The association between weight loss and Chronic Obstructive Pulmonary Disease (COPD) has been recognised from many years. Based on the evidence that nutritional status reflects metabolic disturbances in COPD, the relationship between body mass index (BMI), severity of airflow obstruction and CO diffusing capacity (DL(CO)), that is the functional hallmark of emphysema, is relevant to the management of COPD phenotypes. METHODS: We reviewed 104 patients with COPD (82 males), aged 66 +/- 9 years (mean +/- SD). Height averaged 165 +/- 8 cm, weight 71 +/- 16 Kg, FEV1 50 +/- 18 (% of predicted), RV 169 +/- 49%, and DL(CO) 56 +/- 26%. Multiple linear regression was performed using BMI, FEV1 and RV, as explanatory variables for DL(CO). Patients were also classified into four groups according to BMI < or = 18.5 (low), > 18.5 and < or = 25 (ideal), > 25 and < or = 30 (overweight), > 30 (obese), and post-bronchodilator FEV1 < 50%. Using this categorisation, a two-factor analysis of variance, testing for interaction and main effects (BMI and FEV1) was performed as confirmatory analysis for the association between BMI (kg/m2), FEV1% and DL(CO)%. RESULTS: FEV1 and BMI were significantly and independently associated to DL(CO) according to the equation: DL(CO) = -18.32 + 0.65 x FEV1 + 1.59 x BMI (R2 = 0.40, p < 0.0001). The contribution of RV % to DL(CO) % was largely non-significant (p = 0.16). A close relationship was found between BMI (kg/m2) and DL(CO) %, for all of the four BMI groups segregated by post-bronchodilator FEV1 %, (p < .0001). No interaction was found between these two factors (p = 0.30). CONCLUSION: Nutritional status as assessed by BMI contributes substantially to impairment of DL(CO) independently of the severity of airflow obstruction. This data confirms the association between emphysematous process and weight loss in advanced COPD, independent of the airflow obstruction severity.

Predictors of mortality in patients with Eisenmenger syndrome and admission to the lung transplantation waiting list.

BACKGROUND: Patients with Eisenmenger Syndrome (ES) have very severe irreversible pulmonary hypertension but the criteria for admitting such patients to a lung transplantation waiting list (LTWL) is not clear. Indeed it has been demonstrated that the natural survival of patients with ES is better than the survival achieved through lung transplantation: it follows that no guidelines are available for these patients' admission to an LTWL. The aim of our study was to identify possible predictors of mortality in ES patients in order to reserve admission to the LTWL solely for those patients who would otherwise have the lowest probability of survival. METHODS: Since 1991, 57 patients with ES from our rehabilitative centre were admitted to the LTWL of the Division of Cardiac Surgery at San Matteo Hospital, University of Pavia. At the time of the retrospective analysis, patients were divided into a group of non-transplanted survivors (27 patients--47% of the total) and a group who had died prior to transplantation (16 patients--28% of the total). The 14 transplanted patients (25% of the total) were not considered in the statistical analysis, considering transplantation as an "external event". Unpaired t tests were used to compare the following factors in the survivors and in those who died: sex, "complexity" of the congenital heart disease underlying the ES, previous cardiac surgery, arterial blood gases, pulmonary function and hemodynamic parameters. Moreover, a stepwise discriminant analysis was performed in order to define a possible set of prognostic factors. RESULTS: PaCO2 was higher in those who subsequently died (36.15 +/- 7.42 mmHg) compared with those who survived (32.5 +/- 5.33 mmHg), although this difference did not reach a statistical significance (p = 0.08). Discriminant analysis defined a model in which (a) complexity of the congenital heart disease, (b) sex (male) and (c) cardiac output were predictive of a higher risk of mortality. CONCLUSIONS: This new knowledge can be used in the decision of admission to LTWL in ES patients.

Weakness of respiratory and skeletal muscles after a short course of steroids in patients with acute lung rejection.

There have been occasional reports of acute respiratory and skeletal muscle weakness in intensive care unit patients treated with massive doses of corticosteroids. However, in this setting the concomitant use of other drugs may have influenced the finding. In this study the effects of 5 days of treatment with high doses of steroids in consecutive patients with acute lung rejection after transplantation were systematically evaluated. Maximal inspiratory pressure during phrenic nerve stimulation and peak torque of isokinetic contraction of the quadriceps and hamstring muscles were measured objectively. Compared to the pretreatment condition, approximately 45% of patients showed acute generalised muscle weakness that recovered after approximately 2 months. This demonstrates muscle weakness induced by steroids within patients.

Lung transplantation: the new point of view of an Italian centre.

Lung transplantation has become an accepted therapy for patients with end-stage lung disease. The survival rate after this operation is not, however, satisfactory, being 40-50% at 5 yrs after lung transplantation; infections and pulmonary rejection (acute and chronic) are the cause of this brief survival. Recently, it has been shown that lung transplantation is an advantageous solution only for selected pathologies. The introduction of alternatives to lung transplantation (lung volume reduction surgery in emphysema, prostacyclin therapy in primary pulmonary hypertension and pulmonary thromboendarterectomy in chronic thromboembolic hypertension) has modified the number of patients admitted to the lung transplantation waiting list. In this study, admission to the lung transplantation waiting list in the first 50 and in the following 50 months of activity of the Pulmonary Division Medical Centre of Montescano were retrospectively compared in order to verify whether experience gained has influenced admission to the lung transplantation waiting list. The mortality rate of patients with idiopathic pulmonary fibrosis (44%), chronic thromboembolic pulmonary hypertension (50%) and primary pulmonary hypertension (52%) before lung transplantation was high; the mortality after lung transplantation was low in idiopathic pulmonary fibrosis (16%), but rather high in primary pulmonary hypertension (55%) and chronic thromboembolic pulmonary hypertension (50%). In contrast, the mortality rate of patients with Eisenmenger's syndrome and emphysema was fairly low while on the lung transplantation waiting list, but rather high after lung transplantation. The trend in admission to the lung transplantation waiting list changed during the two observation periods, with a reduction in the number of patients with Eisenmenger's syndrome and emphysema, but not of those with idiopathic pulmonary fibrosis, chronic thromboembolic pulmonary hypertension and primary pulmonary hypertension. The experience gained modified the authors' approach to lung transplantation, but the "world" of lung transplantation still needs a lot more experience.

Incidence and causes of non-invasive mechanical ventilation failure after initial success.

BACKGROUND: The rate of failure of non-invasive mechanical ventilation (NIMV) in patients with chronic obstructive pulmonary disease (COPD) with acute respiratory insufficiency ranges from 5% to 40%. Most of the studies report an incidence of "late failure" (after >48 hours of NIMV) of about 10-20%. The recognition of this subset of patients is critical because prolonged application of NIMV may unduly delay the time of intubation. METHODS: In this multicentre study the primary aims were to assess the rate of "late NIMV failure" and possible associated predictive factors; secondary aims of the study were evaluation of the best ventilatory strategy in this subset of patients and their outcomes in and out of hospital. The study was performed in two respiratory intensive care units (ICUs) on patients with COPD admitted with an episode of hypercapnic respiratory failure (mean (SD) pH 7.23 (0.07), PaCO(2) 85.3 (15.8) mm Hg). RESULTS: One hundred and thirty seven patients initially responded to NIMV in terms of objective (arterial blood gas tensions) and subjective improvement. After 8.4 (2.8) days of NIMV 31 patients (23%; 95% confidence interval (CI) 18 to 33) experienced a new episode of acute respiratory failure while still ventilated. The occurrence of "late NIMV failure" was significantly associated with functional limitations (ADL scale) before admission to the respiratory ICU, the presence of medical complications (particularly hyperglycaemia), and a lower pH on admission. Depending on their willingness or not to be intubated, the patients received invasive ventilation (n=19) or "more aggressive" (more hours/day) NIMV (n=12). Eleven (92%) of those in this latter subgroup died while in the respiratory ICU compared with 10 (53%) of the patients receiving invasive ventilation. The overall 90 day mortality was 21% and, after discharge from hospital, was similar in the "late NIMV failure" group and in patients who did not experience a second episode of acute respiratory failure. CONCLUSIONS: The chance of COPD patients with acute respiratory failure having a second episode of acute respiratory failure after an initial (first 48 hours) successful response to NIMV is about 20%. This event is more likely to occur in patients with more severe functional and clinical disease who have more complications at the time of admission to the ICU. These patients have a very poor in-hospital prognosis, especially if NIMV is continued rather than prompt initiation of invasive ventilation.

The role of the sonologist in a sonographer-based practice.

In many foetal medicine units and private practices, sonographers have gained considerable responsibility and independence. Still, there is a wide divergence of opinion as to their proper role, and to the role of the reporting doctor. The present study examines the role of the sonologist in three sonographer-based obstetric and gynaecological ultrasound practices. During a 25-day period, 14 sonographers filled out a questionnaire for each patient they scanned. Questions included indication for scan, whether or not and why the patient was scanned and/or seen by a sonologist, and abnormalities found. Information regarding 700 patients was obtained. Forty-eight patients were excluded because they were also booked to see a doctor. Of the remaining 652 patients, 74.5% had obstetric indications and 25.5% had gynaecological indications. Ten per cent of all patients scheduled to be scanned only by a sonographer also needed to be scanned by a sonologist, and 34.5% of all patients had contact with a doctor unexpectedly, most commonly to explain findings or arrange treatment and tests. In conclusion, in a sonographer-based practice the sonologist is often required to provide direct patient care beyond simple report writing. Therefore optimal patient management would require an on-site sonologist.

Noninvasive mechanical ventilation in the weaning of patients with respiratory failure due to chronic obstructive pulmonary disease. A randomized, controlled trial.

BACKGROUND: In patients with acute exacerbations of chronic obstructive pulmonary disease, mechanical ventilation is often needed. The rate of weaning failure is high in these patients, and prolonged mechanical ventilation increases intubation-associated complications. OBJECTIVE: To determine whether noninvasive ventilation improves the outcome of weaning from invasive mechanical ventilation. DESIGN: Multicenter, randomized trial. SETTING: Three respiratory intensive care units. PATIENTS: Intubated patients with chronic obstructive pulmonary disease and acute hypercapnic respiratory failure. INTERVENTION: A T-piece weaning trial was attempted 48 hours after intubation. If this failed, two methods of weaning were compared: 1) extubation and application of noninvasive pressure support ventilation by face mask and 2) invasive pressure support ventilation by an endotracheal tube. MEASUREMENTS: Arterial blood gases, duration of mechanical ventilation, time in the intensive care unit, occurrence of nosocomial pneumonia, and survival at 60 days. RESULTS: At admission, all patients had severe hypercapnic respiratory failure (mean pH, 7.18+/-0.06; mean PaCO2, 94.2+/-24.2 mm Hg), sensory impairment, and similar clinical characteristics. At 60 days, 22 of 25 patients (88%) who were ventilated noninvasively were successfully weaned compared with 17 of 25 patients (68%) who were ventilated invasively. The mean duration of mechanical ventilation was 16.6+/-11.8 days for the invasive ventilation group and 10.2+/-6.8 days for the noninvasive ventilation group (P = 0.021). Among patients who received noninvasive ventilation, the probability of survival and weaning during ventilation was higher (P = 0.002) and time in the intensive care unit was shorter (15.1+/-5.4 days compared with 24.0+/-13.7 days for patients who received invasive ventilation; P = 0.005). Survival rates at 60 days differed (92% for patients who received noninvasive ventilation and 72% for patients who received invasive ventilation; P = 0.009). None of the patients weaned noninvasively developed nosocomial pneumonia, whereas 7 patients weaned invasively did. CONCLUSIONS: Noninvasive pressure support ventilation during weaning reduces weaning time, shortens the time in the intensive care unit, decreases the incidence of nosocomial pneumonia, and improves 60-day survival rates.

Risk factors for early death in patients awaiting heart-lung or lung transplantation: experience at a single European center.

BACKGROUND: Our purpose was to establish whether patients on the waiting list for heart-lung or lung transplantation had different survival rates according to diagnosis and to determine the specific variables responsible for early death. METHODS: Between 1988 and 1996, 278 patients were placed on the waiting list for organ transplant. Diagnoses were pulmonary vascular disease in 128, parenchymal disease in 141, and retransplantation in 9 patients. Eighty patients received transplants, 100 patients died awaiting transplantation, and 98 patients are still awaiting transplantation. Univariate and multivariate analyses of risk factors for early death on the waiting list were performed. Patients still listed < or =6 months (n=24), transplanted < or =6 months (n=37), or in the retransplantation group (n=9) were excluded. Of the remaining 208 patients, 52 died < or =6 months and 156 survived >6 months. RESULTS: Patients with primary pulmonary hypertension, pulmonary fibrosis, or cystic fibrosis had statistically significantly lower survival rates at 6, 12, and 24 months (31%, 36% and 26%, respectively, at 24 months) than patients with Eisenmenger's syndrome and chronic obstructive pulmonary disease (76% and 71%). Patients with Eisenmenger's syndrome who died < or =6 months had significantly higher systolic pulmonary artery pressure (134+/-39 vs. 108+/-25 mmHg) and pulmonary vascular resistance (1928+/-1686 vs. 1191+/-730 dyn/sec/cm(-5)) than those who survived longer. Patients with pulmonary fibrosis who died < or =6 months had significantly lower forced vital capacity (36+/-15 vs. 47+/-13% predicted), forced expiratory volume (37+/-14 vs. 48+/-14% predicted), room air PO2 (42+/-11 vs. 50+/-11 mmHg), and room air O2-saturation (78+/-10 vs. 84+/-8%) than those who survived longer. In the multivariate analysis, only the type of pathology was a significant risk factor for death after being on the waiting list < or =6 months. CONCLUSIONS: Certain pathologies and variables are risk factors for early death in patients on the waiting list. This information may be used to allocate specific donor organs to patients in greater need.

Lung retransplantation 3 yrs after heart-lung transplantation.

The main long-term complication after lung transplantation is chronic rejection in terms of obliterative bronchiolitis; when therapy does not arrest the progression of the airflow obstruction, lung retransplantation seems to be. at present, the only strategy in the management of chronic rejection. We report the 12 month follow-up of a single lung retransplantation in a 21 yr old female who had received a heart-lung transplantation 35 months previously for Eisenmenger syndrome. The patient had excellent first allograft function and quality of life for 26 months, then progressively deteriorated due to the occurrence of obliterative bronchiolitis, and further worsened in the following 9 months. At that time, she underwent left lung retransplantation, based on her negative history of infection, low rate of acute rejection, ambulatory status, and young age. She is now doing well at 12 months after retransplantation and her forced expiratory volume in one second is still improving, p thus justifying both retransplantation and hopeful expectation.

Human and financial costs of noninvasive mechanical ventilation in patients affected by COPD and acute respiratory failure.

STUDY OBJECTIVES: It has been suggested that noninvasive mechanical ventilation (NIMV) may be a time-consuming procedure for medical and paramedical personnel. We carried out a prospective trial in 10 consecutive COPD patients aimed at assessing the human and economic resources needed to ventilate patients by NIMV and we compared these with those needed by a group of six patients receiving invasive mechanical ventilation (InMV). DESIGN: The daily cost and the minutes spent by medical doctors (MDs), respiratory therapists (RTs), and nurses (Ns) were recorded during the first 48 h of ventilation in 10 patients during NIMV (group A) and in six who received InMV (group B) after an initial unsuccessful attempt with NIMV. In two subgroups of patients (five for group A and four for group B), the analysis was also performed, except for RTs, for the total length of mechanical ventilation. SETTING: A respiratory ICU. PATIENTS: At hospital admission, the two groups of COPD patients did not differ for blood gas values (PaCO2 = 88.2+/-9.8 mm Hg for group A vs 90.5+/-12.8 mm Hg for group B, and pH = 7.21+0.08 vs 7.20+0.08, respectively) or for clinical and neurologic status, but patients of group B had not tolerated NIMV. MEASUREMENTS AND RESULTS: The total time spent at the bedside in the first 6 h did not differ between group A and B (group A = 72.3 min [MD], 87.2 min [RT], and 178.8 min [N] vs 98.8 min [MD], 12.5 min [RT], and 197.6 min [N] for group B). In the following 42 h, a plateau was reached so that there was a significant reduction for both groups in the time of assistance given by Ns (p<0.001) but not by MDs or RTs. The total costs were also not different between the two groups ($806+/-73 [US dollars per day] vs $864+/-44 for group A and B, respectively). In the subgroups monitored for the entire period of ventilation, a significant reduction in the time of assistance, for both MDs and Ns, was observed after approximately the first half. CONCLUSIONS: We conclude that in the first 48 h of ventilation, daily NIMV is neither more expensive nor time-consuming and staff demanding than InMV. After the first few days of ventilation, NIMV was significantly less time-consuming than InMV, for MDs and Ns, so that medical and paramedical time expenditure seems not to be a major problem during NIMV.

Lung transplantation: the experience of the Thoracic Organ Transplantation Centre of Pavia.

Between January 1991 and September 1995 at the Thoracic Organ Transplantation Centre of Pavia, 193 patients entered the waiting list for heart-lung or lung transplantation. Indications for heart-lung transplantation (HLT) were mainly primary or secondary pulmonary vascular diseases. Parenchymal lung diseases were the most frequent reasons for single- (SLT) or double-lung (DLT) transplantation. During the same period, 21 patients underwent HLT, 16 SLT and 14 DLT. Early deaths (within 30 days of surgery) occurred in 2 (10%) HLT, in 3 (19%) SLT, and in 3 (21%) DLT. Nineteen (90%) patients with HLT, 11 (69%) with SLT, and 10 (71%) with DLT survived up to 3 months; and 11 (52%) patients with HLT, 8 (50%) with SLT, and 5 (36%) with DLT survived up to 12 months. At the time of writing, the following patients are still alive: 10 (48%) with HLT, after a mean +/- SEM follow-up of 37.2 +/- 6 (range 28-46) months, 12 (75%) with SLT, after a mean follow-up of 16 +/- 11 (range 1-35) months, and finally 7 (50%) with DLT, after mean follow-up of 14 +/- 9 (range 1-23) months.

Patient-ventilator interaction and inspiratory effort during pressure support ventilation in patients with different pathologies.

The aim of this study was to evaluate whether pressure support ventilation (PSV) requires different diaphragmatic efforts and patient-ventilator matching, according to the underlying disease. Four groups of patients requiring PSV were studied: Group A, recovering from an episode of acute respiratory failure due to adult respiratory distress syndrome (ARDS); Group B, with postsurgical complications; and two subsets of chronic obstructive pulmonary disease (COPD) patients, with "normal" static compliance of the respiratory system (Cst,rs) (Group C) or elevated Cst,rs (Group D). Ventilatory pattern, transdiaphragmatic pressure (Pdi), the pressure-time product of the diaphragm (PTPdi), static (PEEPi,stat) and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn), Cst,rs and resistance of the total respiratory system (Rrs) were recorded. The matching between patient and ventilator was analysed, recording the number of "ineffective efforts" (inspiratory efforts not efficient enough to trigger a new ventilator cycle, despite a positive deflection in Pdi). A satisfactory blood gas equilibrium arterial oxygen saturation (Sa,O2 > 93%, with a pH > 7.32) was obtained in the various groups with different levels of PSV. Minute ventilation was found to be significantly higher in Groups A and B, due to the longer expiratory time (tE) in the COPD groups. Group A (2 out of 7), Group B (3 out of 7), Group C (3 out of 5) patients showed sporadic "ineffective efforts". All Group D patients manifested continuous mismatching with the ventilator, so that the pressure-time product of the diaphragm per minute (PTPdi/min), reflecting the metabolic work of the diaphragm, was not different in the four groups. Tidal volume and the spontaneous inspiratory efforts were similar in the four groups, but the number of breaths delivered by the ventilator was significantly higher in Groups A and B. The application of different levels of pressure support ventilation in patients with acute respiratory failure due to different pathologies, led them to breathe with comparable pressure time product of the diaphragm. The majority of the patients showed mismatching with the ventilator, although this effect was more pronounced in the groups with chronic obstructive pulmonary disease.

Time course of exercise capacity, skeletal and respiratory muscle performance after heart-lung transplantation.

Recipients of heart-lung transplantation (HLT) show reduced exercise capacity due to several pre- and postsurgical factors. The aim of this study was to evaluate the time course of exercise capacity, and skeletal and respiratory muscle performance in 11 patients (5 females and 6 males; age (mean +/- SD) 38 +/- 13 yrs) undergoing HLT. All of the patients were admitted to our institution for a rehabilitation programme after surgery, and were followed-up for 18 months. On admission, at discharge after an in-patient rehabilitation programme, and every 6 months, patients underwent evaluation of: lung function values; incremental treadmill exercise, 6 min walking distance (6-MWD); maximal inspiratory and expiratory pressures (MIP and MEP, respectively); and peak torque of isokinetic contraction of leg flexor and extensor muscles (IFX and IEX, respectively). On admission, patients had: reduced lung volumes as assessed by vital capacity (VC) (60 +/- 15% of predicted); reduced exercise capacity as assessed by peak oxygen consumption (V'O2,peak) (40 +/- 12% pred); reduced skeletal and respiratory muscle performance as assessed by IEX, IFX (48 +/- 16 and 28 +/- 12 Newton-metres (N x m), respectively) and by MIP and MEP (54 +/- 21 and 58 +/- 19 cmH2O, respectively). Ten patients completed the rehabilitation programme. At discharge, no significant change in dynamic and static lung volumes was observed. However, nonsignificant increases in MIP, MEP, IEX, IFX, 6-MWD and V'O2,peak were recorded. After 6 and 12 months, indices of skeletal and respiratory muscle function and V'O2, peak improved further, but still remained lower than normal values. We conclude that in patients with heart-lung transplantation, skeletal and respiratory muscle function and exercise performance are reduced after surgery, that they may improve with time but are still less than normal after 18 months.