Roberto Porta

Effects of oxygen on autonomic nervous system dysfunction in patients with chronic obstructive pulmonary disease

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.

Outcome of COPD patients performing nocturnal non-invasive mechanical ventilation

The role of non-invasive nocturnal domiciliary ventilation (NNV) in chronic obstructive pulmonary disease (COPD) patients with chronic hypercapnia is still discussed. The aims of this study were to evaluate the long-term survival, the clinical effectiveness and side-effects of NNV in these patients. Forty-nine stable hypercapnic COPD patients on long-term oxygen therapy (LTOT) were assigned to two groups: in Group 1, 28 patients performed NNV by pressure support modality in addition to LTOT; in Group 2, 21 patients continued their usual LTOT regimen. Treatment was assigned according to the compliance to NNV, after an in hospital period. Mortality rate, hospital stay (HS) and ICU admissions (IA) were recorded in the two groups. HS and IA were compared to those recorded in a similar period of follow-back. Lung and respiratory muscle function, dyspnoea, and exercise capacity (by 6-min walk test) were evaluated baseline and every 3-6 months up to 3 yr. Mean follow-up time was 35 +/- 7 months. Mortality rate was not different between the two groups: 16, 33, 46% and 13, 28, 50% at 1, 2 and 3 yr in Groups 1 and 2 respectively. Lung and respiratory muscle function did not significantly change over time. A significant increase in 6-min walk test (from 245 +/- 78 to 250 +/- 88, 291 +/- 75, 284 +/- 89 m after 1, 2 and 3 yr respectively, P < 0.01) was observed only in patients undergoing NNV. In comparison to the follow back HS significantly decreased in both groups (from 37 +/- 29 to 15 +/- 12 and from 32 +/- 18 to 17 +/- 11 days/pt/yr in Groups 1 and 2 respectively, P < 0.001) whereas IA significantly decreased only in patients performing also NNV (from 1.0 +/- 0.7 to 0.2 +/- 0.3/pt/yr, P < 0.0001). Addition of NNV by pressure support modality to LTOT does not improve long term survival but significantly reduces ICU admissions and improves exercise capacity in severe COPD with hypercapnia.

Tele-Assistance in Chronic Respiratory Failure: Patients' Characterization and Staff Workload of 5-Year Activity

BACKGROUND The issue of how to optimize the routine use of tele-assistance (TA) in the clinical care remains to be addressed. Skills and costs of human resources represent the major component to care for chronic patients with TA. METHODS We investigated (1) the change in patient population, mortality, and staff utilization/cost during the first 5-year activity of a TA program (24-h availability of a call center, pulse oxygen device, and second medical opinion) dedicated to chronic respiratory failure patients and (2) the staff time dedicated to each new patient admitted to the service. RESULTS Three-hundred and ninety-six patients (age 64 +/- 17 years; 296 men) were reviewed across 5 years of activity. Patients followed/year increased over time, particularly for amyotrophic lateral sclerosis subjects. Calls/month dramatically increased from 60 to 290, with a 5-year number of calls equal to 12.952. The doctors time dedicated to TA decreased over time, whereas the nurses time increased allowing a cost saving of 39% when compared with budgeted salary costs. The number of home ventilated patients did not change, remaining over 78%. The mortality rate increased over time (from 6% to 11%). Both chronic obstructive pulmonary disease (COPD) and No-COPD patients used the TA service more frequently during the winter, and COPD used it also in the summer. CONCLUSIONS A stable TA service dedicated to chronic respiratory failure may be reached after 4 years. Across years, (1) number of patients increased, with COPD and ventilated subjects being the most representative; (2) calls varied during seasons; (3) doctors workload decreased, saving salary costs; and (4) each new enrolled patient may require 73 and 27 min/month of nurse and doctor, respectively.

Preliminary results on nursing workload in a dedicated weaning center

Objective: To evaluate the nursing time required for difficult-to-wean patients in a dedicated weaning center (WC) and to examine the correlation of the nursing time with nursing workload (NW) scores and with clinical severity and dependency.¶Setting: Four-bed WC of a pulmonary rehabilitation department.¶Intervention: None.¶Design and measurement: Prospective, observational study of 46 consecutive patients admitted to a long-term WC. Time required by items of the Time Oriented Score System (TOSS) and other tasks specific to respiratory intermediate intensive care units were evaluated for all the activities performed on each patient in the first 2 days after admission. Patient dependency and level of nursing care at admission were measured using the Dependence Nursing Scale (DNS) and the Intermediate Therapeutic Intervention Score System (TISS-int). The Acute Physiology and Chronic Health Evaluation (APACHE) II score was also recorded at admission.¶Results: On the first day each patient needed 45 ± 15 % (63 ± 23 %, 45 ± 22 %, and 29 ± 14 % for the three nursing shifts) of allocated single nursing time. On the TOSS on the first day patients required a daily mean 28 ± 10 % of total available nursing time; on the second day the results did not change. Time of care in the first 24 h was only weakly related to DNS, APACHE II score, and TISS-int; only DNS was able (although weakly; r = 0.45) to predict minutes of nursing care.¶Conclusions: In difficult-to-wean patients from mechanical ventilation the nursing time in the first 2 days after admission is high. The use of TOSS may underestimate NW by about 38 %. Although only DNS showed the ability to predict minutes of care, the weak relationship limits its value in clinical practice.

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 (V˙o 2peak) 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 Fenodid 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 andV˙o 2 were significantly (p<0.05) increased at T1 (mean (SE) Wpeak from 89 (5.6) W to 109 (6.9) W);V˙o 2peak 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.

Differences in spontaneous breathing pattern and mechanics in patients with severe COPD recovering from acute excerbation

The aims of this study were to assess spontaneous breathing patterns in patients with chronic obstructive pulmonary disease (COPD) recovering from acute exacerbation and to assess the relationship between different breathing patterns and clinical and functional parameters of respiratory impairment. Thirty-four COPD patients underwent assessment of lung function tests, arterial blood gases, haemodynamics, breathing pattern (respiratory frequency (fR), tidal volume (VT), inspiratory and expiratory time (tI and tE), duty cycle (tI/ttot), VT/tI) and mechanics (oesophageal pressure (Poes), work of breathing (WOB), pressure-time product and index, and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn)). According to the presence (group 1) or absence (group 2) of Poes swings during the expiratory phase (premature inspiration), 20 (59%) patients were included in group 1 and 14 (41%) in group 2. Premature inspirations were observed 4.5+/-6.4 times x min(-1) (range 1-31), i.e. 20+/-21% (3.7-100%) of total fR calculated from VT tracings. In group 1 the coefficient of variation in VT, tE, tI/ttot, PEEPi,dyn, Poes and WOB of the eight consecutive breaths immediately preceding the premature inspiration was greater than that of eight consecutive breaths in group 2. There were no significant differences in the assessed parameters between the two groups in the overall population, whereas patients with chronic hypoxaemia in group 1 showed a more severe impairment in clinical conditions, mechanics and lung function than hypoxaemic patients in group 2. In spontaneously breathing patients with chronic obstructive pulmonary disease recovering from an acute exacerbation, detectable activity of inspiratory muscles during expiration was found in more than half of the cases. This phenomenon was not associated with any significant differences in anthropometric, demographic, physiological or clinical characteristics.

Breathing Pattern and Respiratory Mechanics in Chronically Tracheostomized Patients with Chronic Obstructive Pulmonary Disease Breathing Spontaneously through a Hygroscopic Condenser Humidifier

Hygroscopic condenser humidifiers (HCHs) have been proposed to artificially condition gases breathed by intubated and mechanically ventilated patients. These devices may improve viscosity and coloring of secretions, preventing further bacterial colonization, and heat inspiratory flow in chronically tracheostomized (CT) patients during spontaneous breathing. The aim of this study was to evaluate the effects of HCH on respiratory mechanics and breathing pattern in CT patients with chronic obstructive pulmonary disease (COPD) breathing spontaneously during quiet breathing and maximal voluntary ventilation (MVV). In a prospective, randomized, controlled study on 21 stable spontaneously breathing CT COPD patients, breathing pattern and respiratory mechanics were evaluated by means of a flow sensor and an esophageal pressure (Pes) catheter during quiet breathing in random order either with or without a HCH connected to the tracheostomy. Six of the patients were also studied during maximal voluntary ventilation (MVV). In comparison to without HCH, the application of HCH did not induce changes in the breathing pattern and respiratory mechanics during quiet breathing. As expected, in comparison to quiet breathing, MVV in 6 patients with HCH induced significant changes in respiratory frequency, minute ventilation, mean inspiratory flow, Pes, work of breathing, pressure time product and index. These changes were not significantly different without the application of HCH. In CT COPD patients spontaneously breathing. HCHs have no significant effects on the breathing pattern and respiratory mechanics both during quiet breathing and MVV.

A case of obstructive sleep apnea syndrome associated with floppy eyelid syndrome: positive effect of CPAP therapy

The obstructive sleep apnoea syndrome (OSAS) may be associated with several eyes disorders, among which the most common is the floppy eyelid syndrome (FES). We intended to highlight the association between OSAS and FES and evaluate the effect of FES treatment with Continuous Positive Airway Pressure (CPAP). A 50-year patient with a 10-year history of snoring, sleep fragmentation and daytime sleepiness associated with several comorbidities has been studied. For six months, several ocular symptoms were present, particularly on waking up in the morning. An overnight respiratory polygraphy was performed at baseline and after CPAP titration. The treatment with CPAP corrects apnea/hypopnea events and rapidly improves patients daytime sleepiness and eyes FES-related symptoms. This improvement is already evident after a very short period of treatment.