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Chronic hypoxaemia can play a pathological role in abnormalities of the autonomic nervous system (ANS). In patients with chronic obstructive pulmonary disease (COPD), chronic hypoxaemia is associated with increased mortality and only long-term oxygen therapy is able to improve their survival. Normoxaemic COPD patients have been shown to suffer from abnormalities in ANS function. The aims of this study were to evaluate ANS function in COPD patients with chronic hypercapnic respiratory insufficiency and to test whether oxygen supplementation could reverse any ANS dysfunction. Eleven stable COPD patients with chronic hypercapnic respiratory insufficiency underwent evaluation of ANS by analysis of variability in cardiac frequency at rest and during both vagal (controlled breathing) and sympathetic (tilting) stimuli breathing with and without oxygen supplementation. Thirteen male, healthy, nonsmoking volunteers served as controls. Evaluation of ANS in COPD patients during hypoxic conditions showed alterations both at rest and in response to vagal and sympathetic stimuli. Oxygen supply reversed hypoxaemia without significant changes in arterial carbon dioxide tension and, therefore, ANS alterations were corrected during sympathetic stimulus only. Breathing room air and oxygen, the resting low-frequency (LF) powers were 45+/-15 and 148+/-55 ms2 x Hz(-1), respectively, and controlled breathing LF were 107+/-41 and 141+/-113 ms2 x Hz(-1), respectively. In stable patients with chronic obstructive pulmonary disease with chronic respiratory insufficiency, hypoxaemia is associated with derangements in the autonomic nervous system which may be partially reversed by oxygen administration.

Chronic obstructive pulmonary disease (COPD) is associated with right heart failure and salt and water retention. The possible roles of haemodynamically active hormones in the early stages of COPD have not previously been described. Adrenaline, noradrenaline, renin activity, aldosterone, vasopressin, cortisol, growth hormone, prolactin and atrial natriuretic peptide (ANP) were measured during right heart catheterization in mixed venous blood and in a peripheral artery, in the supine and standing position, in two groups of patients with COPD: Group A with arterial oxygen tension (Pa,O2) < 8.0 kPa (60 mmHg) and Group B with Pa,O2 > 8.0 kPa (60 mmHg). A group of 15 control subjects was studied to obtain control hormonal measurements with a venous blood sample only. Haemodynamic and blood gas values and hormone levels were measured in the supine and standing positions to record changes in the various parameters in COPD patients, and the relationship between pulmonary haemodynamics and hormone levels. No differences were found in hormonal samples between peripheral artery and mixed venous blood. In comparison with the control group, both groups of COPD patients showed a significant reduction in cortisol (p < 0.0001) and in vasopressin (p < 0.005), and an increase in ANP (p < 0.05) and growth hormone (p < 0.05). A marked, but not significant, increase in renin activity, and aldosterone was also found. After standing the increment of adrenaline was significantly higher in COPD patients (p < 0.02). A significant inverse relationship was recorded between forced expiratory volume in one second (FEV1) and noradrenaline (p < 0.02). There is a complex hormonal response even in the early phase of chronic obstructive pulmonary disease. An increase of plasma levels of atrial natriuretic peptide appears to be the earliest neuroendocrine response in these patients.

Noninvasive measurement of the systolic time intervals is a routine procedure for the determination of myocardial performance, even in subjects without clinical or electrocardiographic signs of cardiopathy. Statistically significant differences in pre-ejection period (PEP) and PEP/left ventricular ejection time (LVET) between days and between observations were demonstrated by Levi et al. A high correlation between systolic time intervals and catecholamines was recorded. The aim of the present study was to evaluate the spontaneous modifications in pulmonary and cardiac parameters during a stressful situation, such as right heart catheterization. Seventeen patients with chronic obstructive lung disease (COLD) underwent right heart catheterization. Heart rate (HR), systemic artery pressure (SAP), pulmonary artery pressure (PAP), cardiac output (Q'c), cardiac index (CI), systolic stroke volume (SV), respiratory rate (RR), minute ventilation (V'E), oxygen consumption (V'O2), carbon dioxide production (V'CO2), their ratio (RQ), arterial and venous O2 and CO2, systolic time intervals (total electromechanical interval (QS2), LVET, PEP, PEP/LVET), total pulmonary resistance (TPR), adrenaline (A), and noradrenaline (NA) were recorded at the beginning of the test and 20, 40, 60 and 80 min thereafter. Analysis of variance (ANOVA) showed significant differences between the observations for systolic pulmonary artery pressure (SPAP), Q'c, V'O2, V'CO2, V'E, PEP/LVET, and NA. In conclusion, it is necessary to take into account spontaneous modifications in pulmonary haemodynamic parameters following a stressful situation, such as a catheterization, when studying the effects of drugs such as vasodilators and vasoactive agents.

The aim of this study was to test the usefulness of hygroscopic condenser humidifiers on secretion and on inspired gas temperature in tracheostomized patients. Forty spontaneously breathing chronically tracheostomized patients were divided into two groups: Group 1 received a hygroscopic condenser humidifier connected to the tracheostomy, 24 h daily for 10 days; Group 2, without any protection system, was chosen as the control group. The daily number of tracheal suctions, quantity of aspirate and thickness and colouring of secretions was evaluated. At baseline, and at days 5 and 10, patients were submitted to blood gas analysis, respiratory function tests and sputum analysis. The temperature of gases breathed was measured at rest and during a hyperventilation test, with and without the hygroscopic condenser humidifier. Statistically significant differences were found in thickness and colouring of secretions between the two groups during the period of 10 days. Group 2 showed a significantly greater trend in number of bacteria than Group 1. The group with the hygroscopic condenser humidifier showed respiratory function improvement over time for forced expiratory volume in one second (FEV1) and tidal volume (VT), maximal inspiratory pressure (MIP), and maximal voluntary ventilation (MVV) in comparison to the control group, who did not. Significant differences in the temperature between rest and hyperventilation, with and without a hygroscopic condenser humidifier were also found. In conclusion, a hygroscopic condenser humidifier may be useful in chronically tracheostomized patients who breathe spontaneously, improving viscosity and colouring of secretions, preventing further bacterial colonization, heating inspiratory flow, and helping to improve the functional outcome.

To evaluate possible autonomic nervous system (ANS) dysfunction in patients with chronic obstructive pulmonary disease (COPD) in the absence of any hypoxic neuronal damage, we studied 31 patients with COPD patients aged 31 to 68 years (55 +/- 10) and 32 age-matched healthy subjects (control). Respiratory function in the patients was as follows: FEV1 = 52 +/- 8 percent; PaO2 = 71 +/- 14 mm Hg; and PaCO2 = 40 +/- 10 mm Hg. The ANS was assessed by heart rate variability (HRV) in the time domain (SD of mean RR interval) and frequency domain (autoregressive spectral analysis recognizing low [LF] and high [HF] frequency components, vagal and sympathetic related, respectively). Patients and controls were evaluated at rest and during vagal (controlled breathing [CB]) and sympathetic (passive head-up tilt) maneuvers. Patients with COPD showed a depressed global HRV (rest SD = 34 +/- 20 ms vs 45 +/- 15 ms, p < 0.05; tilt SD = 28 +/- 14 ms vs 38 +/- 13, p < 0.01) with a predominant respiratory drive (rest HF = 44 +/- 28 vs 28 +/- 18, p < 0.05; tilt HF 42 +/- 28 vs 16 +/- 12, p < 0.01) as compared with normal subjects. In the control group, vagal and sympathetic responses were in opposite directions following a stimulus, whereas there was no significant HRV response in the COPD group. We conclude that patients with COPD have abnormalities of ANS function, with in particular a depressed HRV response to sympathetic and vagal stimuli.

Objective: 1) To compare the clinical usefulness of both non-invasive pressure support ventilation (NPSV) and non-invasive intermittent positive pressure ventilation in assist-control (A/C) mode (NIPPV) in chronic obstructive lung disease (COLD) patients with acute hypercapnic respiratory failure: 2) to compare retrospectively the usefulness of non-invasive mechanical ventilation (NMV) with standard medical therapy alone., Design: Prospective randomized retrospective study., Setting: 2 Respiratory intermediate intensive units., Patients: 29 COLD patients (age: 62 +/- 8 years) with chronic respiratory failure were hospitalized in a department for rehabilitation during acute relapses of their disease. They were transferred to our intermediate intensive care unit (IICU) and submitted randomly to either NPSV (16 patients) or NIPPV (13 patients)., Measurements and Results: Blood gas analysis, dynamic flows, clinical variables, success rate, time of ventilation, side effects and subjective score of compliance to therapy. Therapy was considered successful when endotracheal intubation was avoided and patients were returned to their condition prior to exacerbation. No statistically significant difference was found between NPSV and NIPPV in success rate (NPSV 87.5%; NIPPV 77%) or in time of ventilation (NPSV: 69 +/- 49; NIPPV: 57 +/- 49 h). A better compliance to non-invasive mechanical ventilation (NMV) was found in NPSV patients than in NIPPV patients; side effects were observed less frequently in the NPSV group. Comparison of the success rate of NMV was retrospectively performed with 35 control COLD patients with chronic respiratory insufficiency who had undergone an acute relapse of their disease in the 2 years preceding the institution of the IICU and had been treated with oxygen and medical therapy alone. Patients submitted to NMV showed a greater success rate than control (82 versus 54%) after a period of ventilation ranging from 4-216 h., Conclusion: Non-invasive mechanical ventilation performed either by NPSV or NIPPV may improve the outcome of acute exacerbations of COLD, as compared to medical therapy alone. NPSV seems to be more acceptable to patients in comparison with NIPPV.

Changes in cardiopulmonary function were retrospectively evaluated back to two years before acute exacerbations requiring ICU admission in 16 COLD patients with chronic hypercapnic respiratory insufficiency (age: 61 +/- 6 years, group A). Fifteen hypercapnic COLD patients matched for age, sex, lung function, and blood gas values not requiring an ICU admission in a period of two years, served as control subjects (age: 66 +/- 7, group B). Periodic assessments of spirometry, arterial blood gas values, echocardiography, body weight, and red blood cell count performed in stable state were compared for differences between groups and changes over a period of two years. The results indicated that basal body weight, rate of deterioration over time in FEV1, VC, blood gas values, bicarbonates, and RVD may be related to the necessity of ICU admission in COLD patients with hypercapnic respiratory insufficiency.

We retrospectively evaluated the clinical effectiveness of a treatment schedule with intermittent positive pressure ventilation via nasal mask in 49 patients with acute exacerbations of COLD. According to the ability to successfully tolerate a preliminary trial with NIPPV, patients were submitted either to standard treatment plus NIPPV (25 patients) or to ST alone (24 patients). The ST consisted of medical, oxygen and physical therapy. The NIPPV was delivered by a volume cycled ventilator in control mode at least 4 h a day for five consecutive days a week, for three weeks. Comparison of baseline with measurements performed after 10 and 21 days of treatment respectively showed a significant improvement in PaO2 and in PaCO2 in both groups. After 21 days of treatment, VC, FEV1, inspiratory muscle strength, and dyspnea significantly improved in both groups. No significant difference was found between groups at any time of treatment. We conclude that the treatment schedule of NIPPV used is not more effective than ST alone in acute exacerbations of COLD.

Early detection of diastolic dysfunction in chronic obstructive lung disease (COLD) patients could have great prognostic value. Echocardiography has been shown to be a useful technique in studying left ventricular diastolic function. A noninvasive method of studying right ventricular diastolic function has not yet been reported. Pulsed Doppler echocardiography was used to assess right ventricular diastolic function in three groups of subjects: Group I: 35 COLD patients with pulmonary hypertension; Group II: 32 COLD patients without pulmonary hypertension; and Group III: 18 control subjects. Ratios between peak atrial filling velocity (A) and peak early filling velocity (E) (A/E), deceleration half times of the right ventricular rapid filling wave (DHT), and the interval between pulmonary valve closure and tricuspid valve opening (isovolumic relaxation times) (Pc-To) were significantly different in Group I in comparison to Groups II and III. Sensitivity of A/E ratio and Pc-To were 82 and 77%, respectively, and specificity 90 and 72%, respectively; positive predictive values were 90 and 75%, respectively, and negative predictive value 82 and 74% respectively. The multiple correlation coefficient between A/E, acceleration time (ACT), DHT, Pc-To and mean pulmonary artery pressure was 0.75 for Groups I and II together. In conclusion 2D echo-Doppler proved to be useful in evaluating right ventricular diastolic function in all hypertensive COLD patients, revealing a high correlation between diastolic parameters and mean pulmonary artery pressure in both normotensive and hypertensive COLD patients.