Claudio Bruschi

Survival and prediction of successful ventilator weaning in COPD patients requiring mechanical ventilation for more than 21 days

We studied survival and failure or success of weaning from mechanical ventilation (MV) in 42 consecutive chronic obstructive pulmonary disease (COPD) patients requiring prolonged MV (more than 21 days) after an episode of acute respiratory failure requiring admission to our Intermediate Intensive Care Unit (IICU). Parameters including arterial blood gases, pulmonary function tests, respiratory muscle force, neuromuscular drive, and nutritional status were recorded during a phase of clinical stability, in order to identify the features related to survival and weaning. All the patients were submitted to a comprehensive rehabilitation programme. Successful weaning from MV was defined as complete respiratory autonomy for at least 48 h. Twenty three patients were successfully weaned from MV after an average period of 44 days (Group A), requiring no further MV during their stay in hospital, whilst the remaining 19 patients were not able to be disconnected from the ventilator (Group B). The discriminant analysis showed that weaning from MV was significantly associated with arterial carbon dioxide tension (PaCO2), neuromuscular drive (P0.1), maximal inspiratory pressure (MIP), arterial oxygen tension (PaO2), the ratio of respiratory frequency to tidal volume (f/VT) and the serum protein level. Other pulmonary function tests (forced expiratory volume in one second (FEV1), FEV1/forced vital capacity (FVC), anthropometric data, nutritional status, number of pulmonary exacerbations during MV and evidence of cor pulmonale, were similar in the two groups. The discriminant equation considering PaCO2 and MIP could separate the two groups with an accuracy of 84%. The overall survival at 2 yrs was 40%; in Group B it was significantly lower than in Group A (22 vs 68%). Most of the deaths occurred within the first 120 days after intubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Fat-free mass change after nutritional rehabilitation in weight losing COPD: Role of insulin, C-reactive protein and tissue hypoxia

Background: Fat-free mass (FFM) depletion marks the imbalance between tissue protein synthesis and breakdown in chronic obstructive pulmonary disease (COPD). To date, the role of essential amino acid supplementation (EAAs) in FFM repletion has not been fully acknowledged. A pilot study was undertaken in patients attending pulmonary rehabilitation. Methods: 28 COPD patients with dynamic weight loss > 5% over the last 6 months were randomized to receive EAAs embedded in a 12-week rehabilitation program (EAAs group n = 14), or to the same program without supplementation (C group n = 14). Primary outcome measures were changes in body weight and FFM, using dual X-ray absorptiometry (DEXA). Results: At the 12th week, a body weight increment occurred in 92% and 15% of patients in the EAAs and C group, respectively, with an average increase of 3.8 ± 2.6 kg (P = 0.0002) and −0.1 ± 1.1 kg (P = 0.81), respectively. A FFM increment occurred in 69% and 15% of EAAs and C patients, respectively, with an average increase of 1.5 ± 2.6 kg (P = 0.05) and −0.1 ± 2.3 kg (P = 0.94), respectively. In the EAAs group, FFM change was significantly related to fasting insulin (r2 0.68, P < 0.0005), C-reactive protein (C-RP) (r2 = 0.46, P < 0.01), and oxygen extraction tension (PaO2x) (r2 = 0.46, P < 0.01) at end of treatment. These three variables were highly correlated in both groups (r > 0.7, P < 0.005 in all tests). Conclusions: Changes in FFM promoted by EAAs are related to cellular energy and tissue oxygen availability in depleted COPD. Insulin, C-RP, and PaO2x must be regarded as clinical markers of an amino acid-stimulated signaling to FFM accretion.

Obstructive sleep apnoea syndrome : is the half-night polysomnography an adequate method for evaluating sleep profile and respiratory events?

Recently, to reduce the costs of polysomnography, split-night studies have been introduced into routine practice: the first part of the night is used to make the diagnosis of obstructive sleep apnoea syndrome (OSAS) and the second part to achieve an appropriate level of continuous positive airway pressure. Since this split-night protocol has not yet been validated by the comparison of polysomnographic pictures obtained in the first and second parts of the night, the aim of this study was to evaluate sleep profile and respiratory disturbances in the first part (PSG1) and second (PSG2) portion of a standard full-night polysomnographic examination (PSGtot) in a group of OSAS patients. Twenty nine consecutive OSAS patients, aged 54+/-10 yrs; body mass index (BMI) 40+/-6 kg x m(-2) (mean+/-SD values), were studied by separate analyses of PSG1, PSG2 and PSGtot. PSG1 was found to have a low sensitivity value (66%). A significant difference was found between apnoea-hypopnoea indices (AHI) recorded in PSG1, PSG2 and PSGtot (mean+/-SD, AHI1 33+/-27, AHI2 45+/-28, AHItot 40+/-25 events x h(-1), respectively; p<0.01). A strong correlation was observed between AHItot and AHI1 (r=0.89) and between AHItot and AHI2 (r=0.92), but a weaker correlation between AHI1 and AHI2 (r=0.66). These correlations became weaker when patients were subdivided into two different classes on the basis of disease severity. PSG1 was representative of PSGtot and similar to PSG2 only in those patients with rapid eye movement (REM) phase sleep in the first part of the night. We conclude that split-night protocols are not appropriate for evaluating sleep-disordered breathing in obstructive sleep apnoea syndrome patients when rapid eye movement phase sleep does not occur in the first part of the night.

Breathing patterns and HbSaO2 changes during nocturnal sleep in patients with Duchenne muscular dystrophy

SummaryA night-time polygraphic sleep recording with continuous HbSaO2 monitoring was performed in 11 chair-bound Duchenne muscular dystrophy patients with severe restrictive lung disease but with blood gas values within normal limits when awake. No abnormalities of sleep pattern were detected. Nocturnal sleep did not have significant adverse effects on respiration. However, in 6 patients, infrequent central apnoeas or hypopnoeas occurred which were associated with falls in HbSaO2 greater than those that have been reported to be in normal subjects. The magnitude of HbSaO2 falls appeared to be significantly correlated with functional residual capacity values. Overall, the findings revealed a relatively preserved, although unstable, blood O2 balance during nocturnal NREM and REM sleep in patients with Duchenne muscular dystrophy, even in an advanced stage of their illness.

Are COPD Patients with Nocturnal REM Sleep-Related Desaturations More Prone to Developing Chronic Respiratory Failure Requiring Long-Term Oxygen Therapy?

Background: Nocturnal oxygen desaturations (NOD), especially during REM sleep, have been described in patients with COPD. However, the role of NOD in the evolution of COPD to chronic respiratory failure has not been well studied. Objective: The aim of our study was to evaluate whether NOD is a risk factor for the development of chronic respiratory failure in COPD patients. Methods: We studied 34 consecutive COPD patients with a stable daytime PaO2 >60 mm Hg over a period of 42 months. We classified patients as desaturators (NOD) when episodic desaturations were found mainly during REM sleep, independently of baseline SaO2 values. Results: At enrolment 19 patients (55.8%) had NOD. Over the follow-up period, 10 patients (29.4%) were included in a long-term oxygen therapy (LTOT) programme (9 were desaturators). The LTOT was initiated a median time of 22 ± 6.8 months after enrolment. Patients who were subsequently prescribed LTOT had lower values of FEV1 at enrolment, with a higher degree of NOD and PaCO2. Stable respiratory failure developed earlier in patients with NOD: the two enrolment curves for LTOT differed significantly (log-rank test 2.56, p = 0.005). PaCO2, NOD and FEV1 were statistically significantly associated, both in univariate and multivariate Cox proportional hazards analyses, with an increased risk of entering a LTOT programme. Conclusions: We conclude that NOD may represent an independent risk factor for the development of chronic respiratory failure in COPD patients with daytime PaO2 >60 mm Hg. A larger study is needed to confirm the role of NOD in the natural history of COPD and subsequently to identify the most appropriate therapeutic approach.

Differential impact of body position on the severity of disordered breathing in heart failure patients with obstructive vs. central sleep apnoea.

Obstructive (OSA) and central sleep apnoea (CSA) are a common comorbidity in patients with heart failure. The purpose of this study was to assess and compare the impact of body position on the severity of sleep apnoea in these two groups of patients.

Epidemiological diagnosis of asthma: methodological considerations of prevalence evaluation.

Within an epidemiological survey on Chronic Obstructive Pulmonary Disease, before reporting data on the prevalence of bronchial asthma we checked the group of subjects defined as ≪ pathological ≫ by means of a suitable questionnaire and a group of ≪ normals ≫ as a control.We evaluated the sensitivity and specificity of the questionnaire, in comparison with a clinical evaluation made by two physicians and controlled the relationship among their results, non-specific bronchial hyperreactivity and skin tests. In particular the correspondence between diagnosis made by physicians from a clinical evaluation and that obtained by questionnaire was not satisfactory.We suggest the importance of employing physicians for an epidemiological approach to asthma, in absence of a valid objective criterion.

Respiratory Patterns during Sleep in Mitochondrial Myopathies with Ophthalmoplegia

Nocturnal polygraphic recordings (electroencephalography, electro-oculography, submental and intercostal muscle electromyography, electrocardiography, respiration by thoracic strain gauges and oronasal thermistors) with continuous monitoring of arterial oxyhemoglobin saturation by pulse oximeter were performed in 8 patients with ophthalmoplegia plus. All patients except 1 had normal blood gas values and normal lung volumes associated with a diminished ventilatory response to inhaled CO2 during wakefulness. Four patients showed pathological sleep-related breathing patterns consisting of sleep apneic polygraphic tracings mainly of the central type or of REM-related hypoventilation episodes. It is suggested that these disorders in patients with ophthalmoplegia plus may have a central origin and be related to the underlying metabolic disturbance.

Effects of celiprolol on the bronchial reactivity in asthma

In 10 patients with bronchial asthma but normal ventilatory function, celiprolol, a cardioselective beta-adrenoreceptor antagonist, did not significantly affect forced expiratory volume in 1 second (FEV1) or airways resistance (Raw). In contrast, metoprolol substantially reduced FEV1 and increased Raw. In addition, compared with metoprolol, celiprolol induced a greater recovery of FEV1 and Raw after methacholine-induced bronchoconstriction.

Nocturnal sleep and oxygen balance in Duchenne muscular dystrophy : a clinical and polygraphic 2-year follow-up study

SummaryA long-term, clinical and polygraphic investigation of nocturnal sleep was performed in nine non-ambulatory Duchenne muscular dystrophy patients (mean age 16.2 years, range 10–20) with normal daytime blood gas tensions. The data show that nocturnal sleep has some adverse influence on oxygen balance in these patients as suggested by the occurrence of arterial oxyhaemoglobin desaturation occurring mainly during REM stages. This adverse effect tended to worsen significantly within a 2-year period in the absence of any sleep-related symptoms. A significant correlation between the degree of oxygen imbalance during sleep and the degree of restrictive thoratic syndrome during wakefulness was shown.