Expiratory flow-volume curves in mechanically ventilated patients with chronic obstructive pulmonary disease

BACKGROUND: Forced expiratory flow-volume curves are commonly used to assess the degree of airflow obstruction in patients with chronic obstructive pulmonary disease (COPD). In mechanically ventilated subjects, expiratory airways obstruction can only be estimated from relaxed expirations. The aim of this study was to quantify the degree of airways obstruction from relaxed expiratory flow-volume curves in mechanically ventilated patients with COPD. METHODS: As measure of airflow obstruction, the effective time constant during the last 50% of expired volume (tau) was calculated. For bedside monitoring, tau was recalculated as the slope of the flow during the last 50% of expired volume (SF50). In order to study reproducibility, the variables were calculated from consecutive breaths and at different levels of end-expiratory lung volume (EEV). The SF50 and the tau-were correlated with the forced expiratory volume in 1 s (FEV1) measured prior to the start of ventilatory support. RESULTS: Twenty-seven patients were studied with a FEV1 expressed as percentage predicted of 31 +/- 12% (mean +/- SD). The SF50 amounted to 19 +/- 10 degrees. A positive linear correlation was established between SF50 and the FEV1, (%pred), (r = 0.90, P < 0.0001). The tau showed an exponential relationship with FEV1 (%pred), (r2 = 0.78). From 5 consecutive breaths the mean variation coefficient of SF50 was 5 +/- 2%. Changes of delta EEV from 0.05 to 1.00 L did not affect the SF50-values. In 12 patients, mechanically ventilated for respiratory diseases other than COPD, mean tau and SF50 were significantly different from the COPD-patients (P < 0.0001). CONCLUSIONS: This study indicates that relaxed expiratory flow-volume curves can be used to assess airflow obstruction in mechanically ventilated patients with COPD. This information can be used to adapt ventilatory settings.     

Propofol induces bronchodilation in mechanically ventilated chronic obstructive pulmonary disease (COPD) patients

The aim of this study was to evaluate the effects of propofol administration (2 mg · kg^-1 i.v.) on the airways resistances and respiratory mechanics of patients affected by COPD exacerbation, requiring mechanical ventilation. Twenty patients required anaesthesia for diagnostic or therapeutic procedures. Fourteen consecutive patients were divided at random into two groups: Group P received propofol and Group C (control) received only Intralipid 10%; an additional group of six patients received i.v. flunitrazepam (0.03 mg · kg^-1). Lung mechanics (dynamic and static compliance, peak inspiratory pressure, intrinsic positive and expiratory pressure, minimal and maximal resistances of the respiratory system) were evaluated in basal conditions and 3 and 6 min after propofol, Intralipid or flunitrazepam administration. We did not observe significant variations of the evaluated variables after Intralipid or flunitrazepam (Groups C and F), while in patients who received propofol (Group P), we observed the following modifications: dynamic compliance increased from 2.3 ± 0.3 to 2.8 ± 0.4 ml · kPa^-1 (P<0.05), peak inspiratory pressure decreased from 3.3 ± 0.7 to 2.8 ± 0.4 kPa (P <0.05), minimal resistances of the respiratory system (that mainly reflect airways resistances) decreased from 1 ± 0.2 to 0.7 ± 0.2 kPa · 1^-1 · s^-1 (P <0.01). Our results suggest that propofol induces bronchodilation in mechanically ventilated COPD patients, and that this effect is not related specifically to the induction of general anesthesia.     

Exercise in patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) may incur exercise limitation by any one or combination of disturbances in breathing mechanics, oxygen transport, respiratory muscle metabolism or respiratory regulation and sensation. In spite of the increased ventilation demand/capacity ratio in these patients, the relationship between breathing mechanics, respiratory muscle fatigue, the adequacy of alveolar ventilation and the development of exertional dyspnoea is neither clearly defined nor predictable from data obtained with the patient at rest. The issue of oxygen transport during exercise has been complicated by confusion between arterial hypoxia and inadequate volume of oxygen transported to the tissues, which frequently may differ qualitatively and quantitatively. The cardiac output response to exercise in patients with COPD is therefore critical in determining oxygen transport. This response is also impossible to predict from resting lung mechanics, pulmonary arterial blood pressure, arterial oxygen tension or clinical disease profile. Without exercise testing, which includes measurement of all the variables mentioned, it is impossible to define clearly the cause of exercise-induced symptoms in patients with COPD. Exercise training with and without supplemental oxygen has been shown to improve exercise tolerance in these patients, but the precise mechanism of this improvement remains obscure.     

Chronic obstructive pulmonary disease. 4: imaging the lungs in patients with chronic obstructive pulmonary disease

The role of chest radiography and computed tomography in the evaluation of pulmonary emphysema and chronic bronchitis is reviewed.     

Exercise in patients with chronic obstructive pulmonary disease.

Sporadic visits to the local doctor followed sometimes by changes in oral and inhaled bronchodilators and occasionally by the addition of steroids frequently does little to significantly improve symptoms and function in the disabled patient with COPD. As in other chronic diseases, the management of these patients is facilitated by a team approach in conjunction with general rehabilitation principles. The rationale and practical implementation of such a programme has recently been outlined by the American Association of Cardiopulmonary Rehabilitation. These are multifaceted programmes but a key component, as outlined above, is exercise training. In this brief review the various approaches available have been described. Controversy still reigns regarding the optimal modes of training and there are important differences among the several approaches. Two main groups can be delineated. One emphasises the detailed definition of the impaired physiology with therapeutic measures targeted to specific defects. There is good documentation that, conversely, unstructured programmes that use treadmill and free range walking and cycling also improve endurance for walking. Upper extremity training is of additional benefit. Programmes with as little as three sessions per week of 1-2 hours of low intensity activity have achieved success so we know that simple programmes can be helpful. Moreover, without the necessity for complex testing and training methods these programmes can be implemented with relatively low costs. Future investigations to examine the relationship between improved exercise capacity for walking and arm exercise on the one hand, and the ease of performance of activities of daily living on the other, will help to reinforce the effectiveness of exercise programmes.     

Cough threshold in patients with chronic obstructive pulmonary disease

BACKGROUND: Cough is an important symptom of patients with chronic obstructive pulmonary disease (COPD). The cough threshold to citric acid and capsaicin in patients with COPD and in normal volunteers was measured, as well as bronchial hyperresponsiveness to methacholine. METHODS: Nineteen patients with COPD and 22 controls were recruited. Subjects underwent a methacholine bronchoprovocation test and a cough challenge to citric acid and capsaicin. RESULTS: The log citric acid cough threshold D2 (concentration causing two coughs) was significantly lower in patients with COPD (mean 2.17 versus 2.56, mean difference (95% CI) 0.39 (0.04 to 0.74), p = 0.02) but not for capsaicin cough D2 (0.66 versus 0.8, p = 0.41). Sixteen patients with COPD had bronchial hyperresponsiveness which was correlated with baseline FEV1 (r = 0.6, p = 0.01, 95% CI 0.15 to 0.84). CONCLUSIONS: Patients with COPD have a lower cough threshold to citric acid, possibly due to a differential effect of cigarette smoke on citric acid sensitive cough receptors.     

Different CABG methods in patients with chronic obstructive pulmonary disease

BACKGROUND: Pulmonary dysfunction is still a major problem in coronary artery bypass grafting (CABG). The purpose of this randomized study was to determine the effect of different CABG techniques on pulmonary function. METHODS: Fifty eight patients with severe obstructive pulmonary disease had elective isolated coronary surgery. The surgical methods for the patients with chronic obstructive pulmonary disease (COPD) were standard CABG in 18 patients (group 1), beating heart surgery in 19 patients (group 2), and minimally invasive direct coronary artery bypass grafting (MIDCABG) in 21 patients (group 3). RESULTS: The earliest extubation time was from group 3 (p < 0.001). The average stay in the intensive care unit was significantly longer in group 1 (2.6 +/- 1.5 days) than in groups 2 (1.4 +/- 0.8 days) and 3 (1.1 +/- 0.8 days) (p < 0.05). The most prevalent respiratory morbidity was atelectasis that developed in 6 patients from group 1, in 2 patients from group 2, and in 3 patients from group 3. Forced expiratory volumes in 1 second (FEV1) obtained in the second postoperative month were significantly lower than preoperative values only in group 1 (p < 0.05). Forced vital capacity (FVC) values were significantly lower than the preoperative values in all three groups (p < 0.05). CONCLUSIONS: Off-pump bypass surgical procedures are more advantageous than on-pump methods for patients with COPD. These patients can be operated on using the beating heart technique or by using MIDCABG to prevent side effects of CPB on pulmonary function and effects of sternotomy.     

Laparoscopic cholecystectomy for patients with chronic obstructive pulmonary disease

PURPOSE: Laparoscopic cholecystectomy (LC) is accepted as a "gold standard" for treating most gallbladder diseases because it is superior to the open method, causes less postoperative pulmonary dysfunction, and promotes earlier postoperative recovery. The laparoscopically associated adverse effects of a carbon dioxide (CO(2)) pneumoperitoneum, however, such as hypercarbia and arterial acidosis, are more pronounced in patients with chronic obstructive pulmonary disease (COPD). The clinical results of LC for patients with COPD are analyzed in this study. METHODS: Twenty-two patients with COPD (group 1) and undergoing LC were compared with 25 control patients without COPD and also undergoing LC (group 2). Patient demographics, intraoperative end-tidal CO(2) (both before and after CO(2) insufflation), and clinical outcome, including surgical duration, length of postoperative hospital stay, and any associated complications, were analyzed. RESULTS: The procedure of one group 1 patient was converted to the open method, and this patient was excluded from the study. Comprising the COPD group were 20 patients with mild COPD and one patient with moderate COPD. With similar settings of tidal volume and ventilation rate for the two groups, the measured end-tidal CO(2) value was significantly greater for group 1 than for group 2 patients after the creation of a CO(2) pneumoperitoneum (34.2 +/- 2.7 vs. 30.7 +/- 3.6 mm Hg; P =.012). The duration of surgery was similar for groups 1 and 2 (88.9 +/- 36.0 vs. 83.2 +/- 38.3 minutes), as was the duration of the postoperative hospital stay (3.3 +/- 1.6 vs. 3.4 +/- 2.2 days). No pulmonary complications were noted for any of the patients. CONCLUSIONS: LC can be safely performed in COPD patients with mild or even a moderate degree of airway obstruction. Intraoperative CO(2) retention did not complicate the postoperative recovery in terms of the complication rate or the duration of the postoperative hospital stay.     

Preoperative considerations for patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a risk factor for development of intraoperative and postoperative pulmonary complications. Regarding the type and the extent of surgical procedure, patients with COPD are at risk of aggravation of pulmonary function which leads to complicated perioperative course. In order to reduce perioperative complications, preoperative evaluation and preoperative patient preparation are of great importance. Goals of preoperative preparation and anesthesia in patients with COPD are maintaining ventilation-perfusion ratio, preventing development of hipoxemia, intraoperative brochospasm, pneumothorax and disturbances of cardivascular system.     

Psychological distress in chronic obstructive pulmonary disease patients

Stress is defined as the exposure of an individual to a threatening stimulus or overwhelming event. Increased rates of psychological distress have been established in patients with chronic diseases compared to healthy individuals. The objective of the present study is to assess the indicators and correlates of psychological distress in chronic obstructive pulmonary disease (COPD) patients. We evaluated the stress exposure (stressful events that COPD patients and control subjects had been exposed) by a life events checklist and psychological distress by General Health Questionnaire in 74 COPD patients and 30 control subjects. Serum adrenocorticotropic hormone (ACTH) and cortisol levels were measured as biochemical indicators of stress. Distress score was higher in COPD group compared to age‐matched controls, although the stress exposure score were not statistically different; indicating that COPD itself is a source of distress. 92% of COPD patients and 87% of control subjects had varying degrees of distress. Severe distress was more frequent in COPD group. Distress score was further increased in patients with severe COPD and severe hypoxemia.There was no significant difference in serum ACTH and cortisol levels of COPD patients and control subjects and distress scores were not correlated to serum ACTH and cortisol levels. However, serum cortisol was higher in patients with severe hypoxemia. These findings support the importance of screening for psychological distress symptoms in COPD outpatients. Since high degree of distress contributes to impaired quality of life and added morbidity, patients with COPD need a comprehensive care including a psychological evaluation. Copyright © 2008 John Wiley & Sons, Ltd.     

Thermogenic effect of bronchodilators in patients with chronic obstructive pulmonary disease

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) are frequently malnourished and have increased resting energy expenditure (REE). An increase in the work of breathing is generally considered to be the main cause of this hypermetabolism, but other factors may also be implicated. Bronchodilators may decrease the work of breathing by reducing airway obstruction, but beta 2 adrenergic agents have a thermogenic effect. The aim of this study was to determine the effect of salbutamol and ipratropium bromide administration on REE in patients with COPD. METHODS: Thirteen patients (10 men) of mean (SD) age 68.3 (7.3) years and forced expiratory volume in one second (FEV1) 39.0 (17.0)% predicted were studied on three consecutive days. The REE was measured by indirect calorimetry at 30, 60, 120, and 180 minutes after double blind nebulisation of either salbutamol, ipratropium bromide, or placebo in random order. RESULTS: FEV1 increased both after salbutamol and after ipratropium. The difference in the mean response between salbutamol and placebo over 180 minutes was +199 ml (95% CI +104 to +295). The difference in mean response between ipratropium and placebo was +78 ml (95% CI +2 to +160). REE increased after salbutamol but was not changed after ipratropium. The difference in mean response between salbutamol and placebo was +4.8% of baseline REE (95% CI +2.2 to +7.4). Heart rate increased after salbutamol but not after ipratropium. The difference in the mean response between salbutamol and placebo was +5.5 beats/ min (95% CI +2.6 to +8.4). CONCLUSION: Salbutamol, but not ipratropium bromide, induces a sustained increase in the REE of patients with COPD despite a reduction in airway obstruction.


     

Vertebral fractures in patients with chronic obstructive pulmonary disease: the EOLO Study

Summary  This study aimed to evaluate the prevalence of vertebral fractures to investigate the determinants of vertebral fracture risk in patients with COPD. The risk of vertebral fractures is strictly related to the severity of the disease. The use of glucocorticoids and the presence of low values of quantitative ultrasound (QUS) may represent additional risk factors. Introduction  Chronic obstructive pulmonary disease (COPD) appears to be associated with osteoporosis. Our study aimed to evaluate the prevalence of vertebral fractures and to investigate the main determinants of vertebral fracture risk in patients with COPD. Methods  In 3,030 ambulatory COPD patients (1,778 men and 1,262 women) aged 50 years or over, we evaluated: COPD severity, presence of vertebral fractures on lateral chest X-ray and bone status by using a quantitative ultrasound device. Results  In men there was a strong association between COPD severity and fractures (p < 0.001), conversely in women the association between COPD severity and fractures was at limit (p = 0.049). In men, but not in women, glucocorticoid treatment was significantly associated with vertebral fractures. The patients with high or moderate risk of osteoporosis presented an increased risk of vertebral fracture (OR 2.71; 95% CI 2.04–3.60 and OR 1.54; 95% CI 1.26–1.88, respectively). Logistic regression analysis showed that COPD severity and glucocorticoid treatment, both inhaled and oral, were associated with increased risk of vertebral fractures. Conclusion  In COPD patients the risk of vertebral fractures is strictly related to the severity of the disease. The use of glucocorticoids and reduced QUS at calcaneous may represent additional risk factors.     

Exercise capacity after lobectomy in patients with chronic obstructive pulmonary disease

The aim of this study is to clarify whether patients with chronic obstructive pulmonary disease (COPD) lose less exercise capacity after lobectomy than do those without COPD, to the same extent as ventilatory capacity and lobectomy for selected patients with severe emphysema improve exercise capacity like ventilatory capacity. Seventy non-COPD patients (N group), 16 mild COPD patients (M group), and 14 moderate-to-severe COPD patients (S group) participated. Pulmonary function and exercise capacity tests were performed on the same day preoperatively and six months to one year after lobectomy. The S group lost significantly less FEV(1) (forced expiratory volume in 1 s) after lobectomy than did the N or M group (P<0.0001 and P<0.005). However, their loss of exercise capacity was equivalent to that for the N and M groups. For the S group, there was a significant, negative correlation between preoperative FEV(1) % of predicted and percentage change in FEV(1) and maximum oxygen consumption (VO2 max) after lobectomy (r=-0.93, P<0.0001 and r=-0.64, P=0.01). In moderate-to-severe COPD patients, patients with a lower preoperative FEV(1) % of predicted experienced a smaller decrease in FEV(1) and VO2 max after lobectomy.     

慢性阻塞性肺疾病患者失能的研究进展

对慢性阻塞性肺疾病失能模型、影响因素、测评工具及干预措施进行综述,建议提高护理人员对慢性阻塞性肺疾病患者失能的认知,对患者进行综合评估,扩展研究内容,优化测评工具,全面考虑失能影响因素,从提高患者疾病预防和管理能力角度构建护理干预措施。     

Renal functional reserve in patients with severe chronic obstructive pulmonary disease

BACKGROUND: Renal functional reserve is the normal increase in renal blood flow after a protein load, and reduced or absent renal functional reserve is an early index of renal impairment. Renal blood flow is frequently reduced during acute oedematous exacerbations of chronic obstructive pulmonary disease (COPD). It is possible that patients with severe COPD in the stable state may have a reduced or absent renal functional reserve which could be a factor in oedema formation. METHODS: Sixteen stable patients with severe COPD and five normal controls were studied. The mean (SD) arterial oxygen and carbon dioxide tensions (PaO2, PaCO2) and forced expiratory volume in one second (FEV1) of patients with COPD were 8.1 (1.04) kPa, 6.3 (0.69) kPa, and 0.74 (0.27) 1, respectively. The pulsatility index (PI), an index of renovascular resistance, was measured non-invasively by Doppler ultrasonography at baseline and at intervals after a protein load of 250 g steak. RESULTS: The PI fell after the protein load in the normal subjects from 1.04 (0.19) to 0.84 (0.17), mean difference 0.20, 95% confidence interval of difference (CI) 0.14 to 0.27, p < 0.001. In the COPD group there was no change; baseline PI = 1.04 (0.16), PI after protein load = 1.08 (0.19), mean difference = -0.04, 95% CI-0.11 to 0.04, p = NS. Six of the patients with COPD were normocapnic and 10 were hypercapnic (PaCO2 > or = 6.0 kPa). The normocapnic patients had no significant change in PI (baseline PI = 1.07 (0.15), PI after protein load = 1.01 (0.16), mean difference = 0.06, 95% CI -0.03 to 0.15) while in the hypercapnic patients the PI tended to rise (baseline PI = 1.03 (0.17), PI after protein load = 1.12 (0.21), mean difference = -0.09, 95% CI 0.18 to 0.007, p = 0.06). CONCLUSIONS: Renal haemodynamics were unchanged after a protein load in patients with severe COPD, suggesting that they had no renal functional reserve. This may be a factor in the development of oedema frequently seen in patients with severe COPD, particularly in hypercapnic patients.


     

Reduced baroreceptor sensitivity in patients with chronic obstructive pulmonary disease.

Baroreceptor sensitivity, reflected by the slope of the linear regression of the electrocardiographic R-R interval on the rise of systolic blood pressure after injection of phenylephrine, was significantly lower in 27 patients with chronic obstructive pulmonary disease (4.67 +/- 2.67) than in 10 normal subjects (12.07 +/- 3.3) of comparable age (p less than 0.001). In 20 patients in whom right heart catheterisation was performed, pulmonary artery pressure was inversely related to baroreflex sensitivity (r = - 0.603, p less than 0.01). Independent variables such as arterial Po2, Pco2, and mean pulmonary artery pressure were examined in order to assess their ability to predict baroreflex sensitivity. The independent variable that made the most significant contribution was mean pulmonary artery pressure. It seems that the attenuation of baroreflex response in patients with chronic obstructive pulmonary disease is caused mainly by pulmonary hypertension and partly by the central effects of hypoxia and hypercapnia.     

老年慢性阻塞性肺疾病患者的综合家庭肺康复研究

目的 制定适合老年慢性阻塞性肺疾病患者的综合家庭肺康复方案,以提高肺康复效果。方法 将60例病情稳定出院的老年慢性阻塞性肺疾病患者随机分为对照组和干预组各30例。对照组实施常规护理,干预组实施基于证据的综合家庭肺康复方案,干预6个月。采用呼吸困难评分、6 min步行试验、圣乔治呼吸问卷进行效果评价。结果 干预3个月、6个月干预组呼吸困难评分及圣乔治呼吸问卷得分显著低于对照组,6 min步行试验距离显著长于对照组(均P<0.05)。结论 对老年慢性阻塞性肺疾病稳定期患者实施综合家庭肺康复,有助于改善呼吸困难症状、提高机体活动能力、改善生活质量。     

Prone position improves lung mechanical behavior and enhances gas exchange efficiency in mechanically ventilated chronic obstructive pulmonary disease patients

Pronation might favorably affect respiratory system (rs) mechanics and function in volume-controlled, mode-ventilated chronic obstructive pulmonary disease (COPD) patients. We studied 10 COPD patients, initially positioned supine (baseline supine [supine(BAS)]) and then randomly and consecutively changed to protocol supine (supine(PROT)), semirecumbent, and prone positions. Rs mechanics and inspiratory work (W(I)) were assessed at baseline (0.6 L) (all postures) and sigh (1.2 L) (supine(BAS) excluded) tidal volume (V(T)) with rapid airway occlusion during constant-flow inflation. Hemodynamics and gas exchange were assessed in all postures. There were no complications. Prone positioning resulted in (a) increased dynamic-static chest wall (cw) elastance (at both V(Ts)) and improved oxygenation versus supine(BAS), supine(PROT), and semirecumbent, (b) decreased additional lung (L) resistance-elastance versus supine(PROT) and semirecumbent at sigh V(T), (c) decreased L-static elastance (at both V(Ts)) and improved CO(2) elimination versus supine(BAS) and supine(PROT), and (d) improved oxygenation versus all other postures. Semirecumbent positioning increased mainly additional cw-resistance versus supine(BAS) and supine(PROT) at baseline. V(T) W(I)-sub-component changes were consistent with changes in rs, cw, and L mechanical properties. Total rs-W(I) and hemodynamics were unaffected by posture change. After pronation, five patients were repositioned supine (supine(POSTPRO)). In supine(POSTPRO), static rs-L elastance were lower, and oxygenation was still improved versus supine(BAS). Pronation of mechanically ventilated COPD patients exhibits applicability and effectiveness and improves oxygenation and sigh-L mechanics versus semirecumbent ("gold standard") positioning. IMPLICATIONS: By assessing respiratory mechanics, inspiratory work, hemodynamics, and gas exchange, we showed that prone positioning of mechanically ventilated chronic obstructed pulmonary disease patients improves oxygenation and lung mechanics during sigh versus semirecumbent positioning. Furthermore, certain pronation-related benefits versus preprone-supine positioning (reduced lung elastance and improved oxygenation) are maintained in the postprone supine position.