PaO2 increases with coughing in patients with chronic lung disease

We considered if the cyanosis frequently observed during a cough attack in patients with chronic lung disease was due to worsening hypoxemia. To investigate the effects of cough on PaO2, we measured arterial blood gases before and after a voluntary coughing period of 45 sec, in 11 patients with Interstitial Lung Disease (ILD) and 14 patients with Chronic Obstructive Lung Disease (COPD). All patients significantly increased (p less than 0.05) their PaO2 (COPD: from 49 +/- 2 to 60 +/- 2 mmHg; ILD from 44 +/- 2 to 51 +/- 3 mmHg, mean +/- SD) and decreased their PaCO2. We conclude that stable patients with COPD and ILD increase their PaO2 with coughing most likely due to hyperventilation. The cyanosis observed could be due to peripheral circulatory effects of coughing.     

Exercise Endurance in Chronic Obstructive Pulmonary Disease Patients at an Altitude of 2640 meters Breathing Air and Oxygen (FIO2 28% and 35%): A Randomized Crossover Trial

Background: At Bogota's altitude (2640 m), the lower barometric pressure (560 mmHg) causes severe hypoxemia in COPD patients, limiting their exercise capacity. The aim was to compare the effects of breathing oxygen on exercise tolerance. Methods: In a blind, crossover clinical study, 29 COPD patients (FEV₁ 42.9 ± 11.9%) breathed room air (RA) or oxygen (FIO2 28% and 35%) during three treadmill exercise tests at 70% of their maximal capacity in a randomized order. Endurance time (ET), inspiratory capacity (IC), arterial blood gases and lactate were compared. Results: At the end of the exercise breathing RA, the ET was 9.7 ± 4.2 min, the PaO₂ 46.5 ± 8.2 mmHg, the lactate increased and the IC decreased. The oxygen significantly increased the ET (p < 0.001), without differences between 28% (16.4 ± 6.8 min) and 35% (17.6 ± 7.0 min) (p = 0.22). Breathing oxygen, there was an increase in the PaO₂ and SaO₂, higher with FIO₂ 35%, and a decrease in the lactate level. At “isotime” (ET at RA), with oxygen, the SpO₂, the oxygen pulse and the IC were higher and the heart rate lower than breathing RA (p < 0.05). Conclusion: Oxygen administration for COPD patients in Bogotá significantly increased ET by decreased respiratory load, improved cardiovascular performance and oxygen transport. The higher increases of the PaO₂ and SaO₂ with 35% FIO₂ did not represent a significant advantage in the ET. This finding has important logistic and economic implications for oxygen use in rehabilitation programs of COPD patients at the altitude of Bogotá and similar altitudes.     

Exertional hypoxemia is more severe in fibrotic interstitial lung disease than in COPD

Background and objective

Despite its clinical and prognostic significance, few studies have evaluated the severity of exertional oxygen desaturation in fibrotic interstitial lung disease (ILD). Our objectives were to identify clinical and physiological variables that predict the extent of exertional oxygen desaturation in fibrotic ILD and to quantify the severity of desaturation compared to chronic obstructive pulmonary disease (COPD).

Methods

This retrospective study compared the results of 6‐min walk test (6MWT) performed while breathing room air in fibrotic ILD patients and COPD patients eligible for pulmonary rehabilitation. Outcomes included the oxygen saturation (SpO₂) nadir and the change in SpO₂ from rest during a 6MWT. Predictor variables were identified on unadjusted analysis, followed by multivariate analysis to identify independent predictors of desaturation.

Results

The study included 134 patients with fibrotic ILD and 274 patients with COPD. The ILD and COPD cohorts had similar age, sex, frequency of major comorbidities, walk distance, baseline SpO₂ and baseline Borg dyspnoea scores. DL_CO was the strongest predictor of desaturation in both cohorts. Compared to patients with COPD, ILD patients had significantly lower SpO₂ nadir values (88.1 ± 6.4 vs 91.0 ± 4.6) and greater decrease in SpO₂ from baseline (7.4 ± 5.2 vs 4.5 ± 3.7) after adjusting for demographic features and pulmonary physiology (P < 0.0005), with greater between‐group differences at lower DL_CO values.

Conclusion

Patients with fibrotic ILD have greater oxygen desaturation during 6MWT compared to patients with COPD when adjusting for demographic features and pulmonary physiology. These findings suggest the need for disease‐specific studies to evaluate the potential utility of ambulatory oxygen in fibrotic ILD.

     

Sleep quality in chronic obstructive pulmonary disease

Background and objective: Previous reports have shown that patients with chronic obstructive pulmonary disease (COPD) sleep poorly, but the underlying basis remains speculative. The aim of this retrospective study was to determine potential predictors of poor sleep quality in COPD patients. Methods: This is a secondary analysis of two previously published trials investigating the impact of long‐acting bronchodilators on nocturnal oxygen saturation in moderate to severe COPD patients. One hundred and six patients with established COPD were studied. Each patient underwent overnight polysomnography studies in a dedicated university‐affiliated sleep laboratory. Epworth Sleepiness Scores, spirometry and daytime arterial oxygen tension (PaO₂) were also recorded. Univariate and multivariate analysis sought independent predictors of sleep quality from baseline demographic, spirometry and oximetry values. Results: Patients' age was 66.4 ± 7.3 years (mean ± standard deviation), forced expiratory volume in 1 s (FEV₁) 33.4 ± 12.9% predicted and daytime PaO₂ 64 ± 7.5 mm Hg. In comparison with historical normative populations, the cohort demonstrated impaired sleep quality. Sleep efficiency was 66 ± 17% and sleep stage analysis revealed altered architecture with diminished periods of rapid eye movement sleep (12.7 ± 8.3%). In multivariate analysis, daytime PaO₂ correlated independently with sleep efficiency (P = 0.041), whereas FEV₁ positively correlated with arousal index, and age correlated negatively with rapid eye movement sleep duration. Conclusions: Sleep quality is poor in patients with severe COPD compared with normative populations of similar age, and daytime hypoxaemia is independently associated with impaired sleep efficiency.     

Identification of Three Exercise-induced Mortality Risk Factors in Patients with COPD

The survival rate of chronic obstructive pulmonary disease (COPD) patients with severely reduced exercise capacity is extremely low. We recently identified three life-threatening pathophysiological conditions during cardiopulmonary exercise testing (CPET): (1) exercise-induced hypoxemia, (2) sympathetic overactivity, and (3) progressive respiratory acidosis at low-intensity exercise. The present prospective observation study aimed to determine whether these parameters constitute risk factors of mortality in moderate-to-very severe COPD. Ninety-six COPD patients were followed-up, monthly, for >3 years. Subsequently, spirometry and CPET were performed to examine parameters of exercise-induced hypoxemia ([PaO₂ slope, mmHg/L · min^?1] = Decrease in PaO₂/ΔV˙ O₂ (Difference in ΔV˙ O₂ between at rest and at peak exercise)), progression of acidosis ([ΔpH/ΔV˙ O₂,/L · min^?1] = Decrease in pH/ΔV˙ O₂), and sympathetic overactivity ([Δnorepinephrine (NE)/ΔV˙ O₂, ng/mL/L · min^?1] = Increase in NE/ΔV˙ O₂). Univariate analysis revealed a significant association between the three conditions with increased mortality. Kaplan–Meier analysis showed that the quartile combining the steepest PaO₂ slope (≤–55 mmHg/ΔV˙ O₂ [L/min]), steepest decrease in arterial blood pH (≤ –1.72/ΔV˙ O₂ [L/min]), and most rapid increase in plasma NE level (≥ 5.2 ng/VO₂ [L/min]) during incremental exercise was associated with higher all-cause mortality. These conditions showed cumulative effects on COPD patients’ survival. Multivariate analyses revealed that these three life-threatening factors are also independent predictors of mortality based on age, heart rate and PaO₂ at rest, body mass index, and forced expiratory volume in 1 s. Thus, these new exercise-induced mortality risk factors may lead to more efficient pulmonary rehabilitation programs for COPD patients based on patient-specific exercise-induced pathophysiological profiles.     

Explained variance for blood gases in a population with COPD

Introduction: Variation of blood gas levels in chronic obstructive pulmonary disease (COPD) patients has not been extensively reported and there is limited knowledge about predictors of chronic respiratory failure in COPD patients. Objectives: The aim of this study was to identify predictors of hypoxemia, hypercapnia and increased alveolar‐arterial oxygen difference in COPD patients. We hypothesized that prediction of arterial blood gases will be improved in multivariate models including measurements of lung function, anthropometry and systemic inflammation. Methods: A cross‐sectional sample of 382 Norwegian COPD patients, age 40–76, Global Initiative for Chronic Obstructive Lung Disease stage II–IV, with a smoking history of at least 10 pack‐years, underwent extensive measurements, including medical examination, arterial blood gases, systemic inflammatory markers, spirometry, plethysmography, respiratory impedance and bioelectrical impedance. Possible predictors of arterial oxygen (PaO₂), arterial carbon dioxide (PaCO₂) and alveolar‐arterial oxygen difference (AaO₂) were analyzed with both bivariate and multiple regression methods. Results: We found that various lung function measurements were significantly associated with PaO2, PaCO₂ and AaO₂. In addition, heart rate and Fat Mass Index were predictors of PaO₂ and AaO₂, while heart failure and current smoking status were associated with PaCO₂. The explained variance (R²) in the final multivariate regression models was 0.14–0.20. Conclusions: With a wide assortment of possible clinical predictors, we could explain 14–20% of the variation in blood gas measurements in COPD patients. Please cite this paper as: Saure EW, Eagan TML, Jensen RL, Voll‐Aanerud M, Aukrust P, Bakke PS and Hardie JA. Explained variance for blood gases in a population with COPD. Clin Respir J 2012; 6: 72–80.     

Patent Foramen Ovale among Patients with Mild Chronic Obstructive Pulmonary Disease and Unexplained Hypoxia

Purpose: To evaluate whether patent foramen ovale (PFO) is a contributing factor to hypoxia in patients with chronic obstructive pulmonary disease (COPD). Methods: Twenty‐one patients over 40 years of age with mild COPD (Forced expiratory volume (FEV1)/Forced Vital Capacity (FVC): > 50%) who had hypoxia (PO₂ < 80 mmHg, SaO₂ < 95%) that could not be explained by COPD alone were included in this study. Arterial oxygen pressures (PO₂) and arterial oxygen saturations (SaO₂) were recorded from laboratory evaluations of arterial blood gases. Respiratory function tests were performed to analyze the degree of COPD. Standard and contrast echocardiography was used to calculate pulmonary artery pressure (PAP) levels and to determine patients with a PFO. Results: The mean age of the patients was 64 ± 12 years. Four patients (19%) had a PFO. The mean PO₂, mean SaO₂, and mean PAP levels were 57.4 ± 6.8 mmHg, 90 ± 3.2%, and 33.8 ± 5.4 mmHg, respectively, in patients without PFO. The mean PO₂, mean SaO₂, and mean PAP levels were 46.5 ± 13.7 mmHg, 79.3 ± 12.8%, and 42.5 ± 6.5 mmHg, respectively, in patients with PFO. There were no statistically significant differences noted between the two groups in the PO₂ levels (P = 0.172) and SaO₂ levels (P = 0.065). A comparison of the PAP levels revealed a statistically significant difference between the two groups, with values that were more elevated in the PFO group than in the non‐PFO group (P = 0.031). Conclusion: This study demonstrated that PFO is not a contributing factor to deep hypoxia in COPD patients with lower PO₂ and SaO₂ levels; however, higher PAP levels were detected in patients with a PFO. Further studies involving a larger number of patients are needed to be conclusive. (Echocardiography 2010;27:687‐690)     

Physical Activity of Patients with COPD from Regions with Different Climatic Variations

Seasonal changes in physical activity in daily life (PADL) of patients with Chronic Obstructive Pulmonary Disease (COPD) living in regions of the world with contrasting (i.e., mild or marked) weather variations have not been yet investigated. We aimed to quantify PADL and compare its variability caused by seasonality in patients with COPD who live in world regions with different summer-winter climatic variations (i.e. Londrina, Brazil and Leuven, Belgium). In a longitudinal, prospective and observational study, patients with COPD from Brazil and Belgium wore the SenseWear Armband for 7 days in summer and 7 days in winter. Active time (≥2METs) was the primary outcome. PADL data were matched day-by-day with weather information. Regarding the two assessment moments, median (min;max) temperatures were 11 (?5.5;27.2)°C in Leuven and 21 (7;27)°C in Londrina. Patients in Brazil (n = 19, 69 ± 7 years, FEV¹ 47 ± 15%_pred) and Belgium (n = 18, 69 ± 6 years, FEV¹ 50 ± 15%_pred) decreased their active time in winter compared to summer (p < 0.05), and this reduction was more pronounced in Brazil (p = 0.01, between group). Mean, minimum and maximum temperature, daylight duration and relative humidity were significantly related to active time. Patients with COPD decrease their PADL in winter even in a region with milder climatic variation.     

Long-term Recording of Night-Time Respiratory Symptoms in Patients with Stable COPD II–IV

Introduction: Night-time respiratory symptoms have a considerable impact on sleep and life quality in patients with chronic obstructive pulmonary disease (COPD). Lack of awareness of night-time symptoms can lead to worsened COPD control. Automated long-term monitoring of respiratory symptoms with LEOSound enables assessment of nocturnal wheezing and cough. Methods: In this observational study we investigated the prevalence and severity of cough and wheezing in patients with stable COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) II–IV] disease for two consecutive nights with the LEOSound system. 48 patients (30 males, 63%) were eligible for inclusion, median age was 67 years, and body mass index (BMI) was 25.3 kg/m². Results: In 15 out of 48 patients (31%), we found wheezing periods for at least 10-minute duration. Wheezing periods >30 minutes were monitored in seven patients and wheezing periods >60 minutes were monitored in three patients. The maximum duration of wheezing was 470 minutes in one patient with COPD II. The median wheezing rate differed between the COPD stages and between active and non-active smokers. Cough was found in 42 patients (87.5%) with a range of 1–326 events. The cough-period-index in night one was 0.83 n/hour (P25:0.33||P75: 2.04) and night two 0.97 n/hour (P25:0.25||P75: 1.9). Most of the cough events were non-productive with a median of 0.86. Conclusions: Night-time symptoms are common in COPD patients. LEOSound offers an opportunity to evaluate objectively night-time symptoms like wheezing and cough in patients with COPD which remain otherwise unnoticed. We found a high incidence of night-time wheezing in these patients, which was related to persistant smoking.     

Drug therapy of sleep-related hypoxaemia

In patients with chronic obstructive pulmonary disease (COPD) exhibiting daytime hypoxaemia, a worsening of the latter occurs during sleep, particularly during REM sleep. The most efficient therapy of this sleep-related hypoxaemia is the nocturnal administration of O₂ at a flow rate of 1.5–3 l/min. An alternative therapy, when daytime hypoxaemia is not too severe (PaO₂>55 mmHg), is the use of almitrine (100 mg/day), a drug which improves daytime hypoxaemia in most COPD patients. The improvement of sleep hypoxaemia with almitrine is related to the increased daytime PaO₂ and cannot be considered as a specific effect of almitrine on sleep-related respiratory events. It must be emphasized that almitrine is ineffective in about 25% of COPD patients (“nonresponders”) and that almitrine can be used with conventional O₂ therapy in patients with severe hypoxemia (day-time PaO₂<55mmHg).     

Fluorescence optical fibre sensor provides accurate continuous oxygen detection in rabbit model with acute lung injury

Background and objective: Continuous monitoring of PaO₂ in seriously ill patients is an important aspect of clinical management, especially for patients with acute lung injury (ALI) or acute respiratory distress syndrome. We have developed a fibreoptic sensor to detect PaO₂in vivo based on fluorescence quenching technology. In this study we evaluated the sensitivity of this sensor in monitoring PaO₂ in a rabbit model with ALI. Methods: The oxygen sensor is a membrane made of Ru(dpp)₃(PF6)₂, poly‐2‐methacryloyloxyethyl phosphorylcholine and butylmethacylate copolymer p‐(MPC‐co‐BMA) located at the tip of the optical fibre. The sensor was inserted into the carotid artery of the animals and monitored PaO₂ continuously. Oleic acid was intravenously injected to induce lung injury. Simultaneous comparisons were made between PaO₂ measured by blood gas analysis and PaO₂ measured by the fibreoptic sensor, both before and after lung injury. Results: The fluorescence intensity decreased gradually following ALI, reflecting increasing hypoxia. Correlation coefficients between measurements by the oxygen sensor and by the blood gas analysis were 0.995 ± 0.003, 0.994 ± 0.002 and 0.993 ± 0.005 (P < 0.05) for control animals, animals with ALI and animals with electrolyte disturbance, respectively. The bias and precision for normal animals was ?1.5 ± 10.8 mm Hg, for animals with ALI was ?1.2 ± 11.2 mm Hg and for animals with electrolyte disturbance was ?1.4 ± 9.2 mm Hg. Conclusions: The oxygen sensor showed high accuracy and stability for continuous monitoring of PaO₂ in normal animals, in animals with ALI and in animals with electrolyte disturbance, suggesting that it may be clinically useful in the continuous measurement of oxygen partial pressure.     

Statin Therapy is Associated with Decreased Pulmonary Vascular Pressures in Severe COPD

Background: Pulmonary hypertension (PH) in COPD carries a poor prognosis. Statin therapy has been associated with numerous beneficial clinical effects in COPD, including a possible improvement in PH. We examined the association between statin use and pulmonary hemodynamics in a well-characterized cohort of patients undergoing evaluation for lung transplantation. Methods: We conducted a cross-sectional analysis of 112 subjects evaluated for lung transplant with a diagnosis of COPD. Clinical characteristics, pulmonary function, cardiac catheterization findings and medical comorbidities were compared between statins users and non-users. Results: Thirty-four (30%) subjects were receiving statin therapy. Statin users were older and had an increased prevalence of systemic hypertension and coronary artery disease (CAD). Mean pulmonary arterial pressure (mPAP) in the statin group was lower [26 ± 7 vs 29 ± 7 mmHg, p = 0.02], as was pulmonary artery wedge pressure (PAWP) [12 ± 5 vs. 15 ± 6 mmHg, p = 0.02]. Pulmonary vascular resistance did not differ between the groups. In multiple regression analysis, statin use was associated with a 4.2 mmHg (95% CI: 2 to 6.4, p = <0.001) lower PAWP and a 2.6 mmHg (95% CI: 0.3 to 4.9, p = 0.03) reduction in mPAP independent of PAWP. Conclusions: In patients with severe COPD, statin use is associated with significantly lower PAWP and mPAP. These finding should be evaluated prospectively.     

Serum Total Antioxidant Status in Severe Exacerbation of Asthma: Correlation with the Severity of the Disease

Oxidative processes, mediated by oxygen free radicals are recognized to contribute significantly to the inflammatory pathology of bronchial asthma. An imbalance between oxidants and antioxidants has also been proposed in this disease. This study examines the serum total antioxidant status (TAS) in asthmatic patients with severe exacerbation of their disease and the probable correlation with clinical or laboratory findings. The TAS was measured in 20 patients (10 men and 10 women, with a mean age of 41.95 ± 20.75 years), using a colorimetric method. On the days of admission and discharge, the forced expiratory volume in 1 sec (FEV₁), the partial arterial oxygen pressure (PaO₂), and severity criteria were recorded and correlated with TAS at the same time. The TAS was also measured in 10 healthy subjects (8 men and 2 women, mean age of 39 ± 9 years). A statistically significant decrease of TAS was observed on admission day compared to that on discharge day (0.98 ± 0.08 vs. 1.12 ± 0.17 mmol/L, p < 0.001, respectively, paired t‐test) suggesting the presence of oxidative stress during an asthma attack. The TAS on admission was also statistically significantly decreased compared to that of normal subjects (0.98 ± 0.08 vs. 1.19 ± 0.09 mmo/L, p < 0.001, respectively, paired t‐test). A statistically significant correlation was observed between FEV₁change and TAS change, from admission to discharge day (r = 0.58, p = 0.007, Pearson correlation). Finally, a statistically significant correlation was found between FEV₁change and TAS on discharge day (r = 0.65, p = 0.002). Decreased TAS was found during an asthma attack, probably as a consequence of increased oxidative stress. The TAS change was correlated with severity criteria, such as FEV₁. Therefore, it seems that measurement of TAS could be a simple and useful tool in the evaluation of an asthma attack. The supplementary administration of antioxidants in future needs further clarification.     

Long-Term Oxygen Therapy in COPD Patients Who Do Not Meet the Actual Recommendations

Chronic respiratory failure due to chronic obstructive pulmonary disease (COPD) is an increasing problem worldwide. Many patients with severe COPD develop hypoxemic respiratory failure during the natural progression of disease. Long-term oxygen therapy (LTOT) is a well-established supportive treatment for COPD and has been shown to improve survival in patients who develop chronic hypoxemic respiratory failure. The degree of hypoxemia is severe when partial pressure of oxygen in arterial blood (PaO₂) is ≤55 mmHg and moderate if PaO₂ is between 56 and 69 mmHg. Although current guidelines consider LTOT only in patients with severe resting hypoxemia, many COPD patients with moderate to severe disease experience moderate hypoxemia at rest or during special circumstances, such as while sleeping or exercising. The efficacy of LTOT in these patients who do not meet the actual recommendations is still a matter of debate, and extensive research is still ongoing to understand the possible benefits of LTOT for survival and/or functional outcomes such as the sensation of dyspnea, exacerbation frequency, hospitalizations, exercise capacity, and quality of life. Despite its frequent use, the administration of “palliative” oxygen does not seem to improve dyspnea except for delivery with high-flow humidified oxygen. This narrative review will focus on current evidence for the effects of LTOT in the presence of moderate hypoxemia at rest, during sleep, or during exercise in COPD.     

Six‐minute walk test: observed adverse events and oxygen desaturation in a large cohort of patients with chronic lung disease

Background: The 6‐min walk test (6MWT) is widely used to assess patients with chronic lung disease (CLD). Anecdotal reports and studies in small numbers of patients with CLD suggest that complications associated with the 6MWT are rare. This study reports the incidence of observed adverse events during the 6MWT in patients referred to an outpatient pulmonary rehabilitation service. Methods: Seven hundred and forty‐one patients with stable CLD (chronic obstructive pulmonary disease (COPD), n= 572) completed the 6MWT in accordance with a standardized protocol that included continuous monitoring of oxygen saturation (SpO₂) and heart rate (Polar). Results: Adverse events occurred in 43 tests (6%). One 6MWT was terminated by the tester because of chest pain and one patient developed persistent tachycardia and irregular pulse immediately following the test. In 35 tests, the tester instructed the patient to stop walking because of profound oxygen desaturation (SpO₂ < 80%). Six patients prematurely terminated the 6MWT because of symptoms. Forty‐seven per cent (n= 345) of patients exhibited significant oxygen desaturation (≥4% fall in SpO₂ to <90%). Pre‐exercise SpO₂ was a significant predictor of desaturation in the COPD (1.79, 1.54–2.08, adjusted odds ratio (OR), 95% confidence intervals) and ILD (OR 1.40, 1.11–1.77) cohorts with FEV₁ (forced expiratory volume in 1 s) also a predictor in COPD (OR 3.02, 1.77–5.15). Conclusion: Profound oxygen desaturation is the most common adverse event observed during the 6MWT in patients with stable ILD and COPD. We propose that the American Thoracic Society 6MWT guidelines are revised to recommend continuous monitoring of SpO₂ during the 6MWT in patients with ILD and COPD.     

Hypoxia during bronchoalveolar lavage

The aim of this study was to determine the degree and duration of hypoxaemia during bronchoalveolar lavage (BAL) and to examine the effect of supplemental oxygen on this response. Transcutaneous oxygen tension (PO₂) was recorded continuously in 22 patients having bronchoscopy alone (Group 1), and during BAL in patients with a variety of connective tissue disorders. Thirty eight of these patients were breathing room air (Group 2) and 28 were given supplemental oxygen (Group 3). The mean fall in PO₂ in Group 1 was 12 ±3 mmHg and the PO₂ in these subjects rose promptly to the initial value once the bronchoscopy was finished. The mean falls in Groups 2 and 3 were 24±4 and 32±5 mmHg and the mean times taken for the PO₂ values to return to baseline after the procedure were 47±9 and 53±10 minutes respectively. The PO₂ fell to less than 60 mmHg in 76% of the patients in Group 2 but in only 25% of those in Group 3. It is recommended that supplemental oxygen be given to all patients having BAL during and for one hour after the procedure and that oxygenation be monitored continuously throughout the bronchoscopy. Arterial blood gases should be always measured prior to bronchoscopy and BAL. In those cases where it is not possible to maintain the PaO₂ at 70 mmHg or more the procedure should be undertaken with great care and with due consideration of the risk of the hypoxaemia that may occur.     

Non-Invasive Ventilation (NIV) and Homeostatic Model Assessment (HOMA) Index in Stable Chronic Obstructive Pulmonary Disease (COPD) Patients with Chronic Hypercapnic Respiratory Failure: A Pilot Study

The effects of Non-invasive Ventilation (NIV) on Insulin Resistance (IR) in stable Chronic Obstructive Pulmonary Disease (COPD) patients have not been fully explored. The aim of this study was to assess the effects of NIV on IR and adiponectin levels during one year application of NIV in stable COPD patients with Chronic Hypercapnic Respiratory Failure.

Twenty-five (25) stable COPD patients with Chronic Hypercapnic Respiratory Failure and with no self-reported comorbidities completed the study. NIV was administered in the spontaneous/timed mode via a full face mask using a bi-level positive airway pressure system. Spirometry, blood pressure, arterial blood gases, dyspnea, daytime sleepiness, serum fasting glucose and insulin levels were assessed. IR was assessed with the calculation of the Homeostatic Model Assessment (HOMA) index. Adiponectin was measured with radioimmunoassay. Study participants were re-evaluated on the first, third, sixth, ninth and twelfth month after the initial evaluation.

There was a significant improvement in FEV₁ values from the first month (34.1 ± 11.6% vs 37 ± 12.3%, p = 0.05). There was a significant decrease in IR by the ninth month of NIV use (3.4 ± 2.3 vs 2.2 ± 1.4, p < 0.0001), while adiponectin levels significantly improved from the first month of NIV use. Stepwise regression analysis revealed that baseline HOMA index was associated with p_aCO₂ (? = 0.07 ± 0.02, p = 0.001), while baseline adiponectin levels were associated with FVC (? = 0.05 ± 0.02, p = 0.035) and the concentration of serum bicarbonate (HCO_3-) (-? = 0.18 ± 0.06, p = 0.002). Insulin sensitivity and glucose metabolism as well as adiponectin levels improved along with the improvements in respiratory failure.     

Should patients have right heart catheterization prior to long-term oxygen treatment?

The presence of pulmonary hypertension (PH) is not an obligatory prerequisite for prescribing long-term oxygen therapy (LTO) in patients with chronic obstructive pulmonary disease (COPD), at least when PaO₂ is repeatedly < 55 mmHg in a stable state of the disease. It is generally acceted that LTO is indicated in patients whose PaO₂ is in the range 55–59 mmHg, but exhibiting polycythaemia, “cor pulmonale”, and (or) PH. The clinical signs of “cor pulmonale” occur late and the noninvasive diagnosis of PH is not yet satisfactory; it ensues that right heart catheterization is useful in these patients, before prescribing LTO. Pulmonary hypertension is probably the most important consequence of long-standing hypoxaemia and, in our opinion, the presence and the degree of PH should be assessed in every patient before starting such a heavy therapy as LTO.     

Langzeitsauerstofftherapie

Diseases with chronic hypoxemia are associated with decreased quality of life and exercise capacity as well as increased morbidity and mortality which can all be improved by long-term oxygen therapy (LTOT). LTOT is indicated if the arterial oxygen partial pressure under resting conditions during a stable state of the disease is ≤55 mmHg (7,3 kPa) and oxygen therapy leads to an improvement of PaO₂ to ≥60 mmHg (8 kPa) or ≥10 mmHg (1,3 kPa). In patients with normal PaO₂ at rest but exercise-induced hypoxemia (PaO₂ ≤55 mmHg/7,3 kPa) LTOT can be applied if the PaO₂ improves to ≥60 mmHg (8 kPa) or if it leads to an improvement of exercise tolerance. Furthermore LTOT is indicated if a PaO₂ of 55–60 mmHg is measured and there is a coexistence of a cor pulmonale or polycythemia. The oxygen flow as well as the system used for oxygen therapy has to be correctly documented for each individual patient.     

Microalbuminuria in Chronic Obstructive Pulmonary Disease

Abstract

Background: Microalbuminuria is an important risk factor for cardiovascular diseases. Microalbuminuria may be seen due to hypoxemia in patients with chronic obstructive pulmonary disease (COPD). Objectives: In this study, we investigated prevalence and relationship of microalbuminuria with clinical and physiological parameters in patients with COPD. Method: During the research, 66 consecutive patients with COPD and 40 cases smokers with normal spirometry were included. The urinary albumin creatinin ratio (UACR) was calculated according to previously described formula. The presence of microalbuminuria was defined as UACR being ≥20 in men and ≥30 in women. The severity index of chronic diseases was evaluated by using MCIRS. Results: The rate of presence of microalbuminuria and UACR were higher in patients with COPD than smokers with normal spirometry. Pearson correlation analysis showed a significant inverse relationship between UACR and PaO₂, FEV₁%, FVC%. On the other hand, there was a positive relationship between UACR and BODE index. There was a significant relationship between the presence of microalbuminuria with PaO2 and BODE index. In the linear regression model, there was a negative relationship between UARC and PaO₂ yet there was a significantly positive relationship between UARC and MCIRS score, BODE index. In the logistic regression model, the presence of microalbuminuria showed significant associations with PaO₂, BODE index. Conclusion: Microalbuminuria may be seen in patients with COPD, depending on the severity of disease and hypoxemia. Microalbuminuria in patients with severe COPD should be examined in regular periods for risk of cardiovascular morbidity or mortality.