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PubMed2001

[Detection of exhaled CO as a simple non-invasive tool for monitoring acute exacerbations of asthma in the elderly].

Exhaled carbon monoxide (CO) concentrations were measured on a CO monitor by vital capacity maneuvers in asthmatic patients either receiving or not receiving inhaled corticosteroids, and in nonsmoking healthy control subjects. CO was detectable and measured reproducibly in the exhaled air of all subjects. The exhaled CO concentrations were higher in asthmatic patients not receiving inhaled corticosteroids and similar in asthmatic patients receiving inhaled corticosteroids and nonsmoking healthy control subjects (Am J Respir Crit Care Med 1997: 156: 1140-1143). All patients with inhaled corticosteroid treatment had reductions in exhaled CO concentration and eosinophil cell counts in sputum that were accompanied by an amelioration of airway obstruction. These results showed that detection of exhaled CO could be a simple non-invasive tool for monitoring airway inflammation and acute exacerbation of asthma.

Aged↗
PubMed2006

Differential effect of cigarette smoking on hydrogen peroxide and thiobarbituric acid reactive substances exhaled in patients with community acquired pneumonia.

BACKGROUND: This study was designed to investigate the effect of cigarette smoking on hydrogen peroxide (H2O2) and thiobarbituric reactive substances (TBARs) concentrations in exhaled breath condensate (EBC) in patients with community acquired pneumonia (CAP). METHODS: H2O2 and TBARs concentrations in EBC were determined with spectrofluorimetrical assays. RESULTS: Non-smoking CAP patients (n = 24) exhaled 1.4, 1.8 and 1.7 times more H2O2 than the smoking patients with CAP (n = 19) as assessed one (0.73 +/- 0.32 microM v. 0.51 +/- 0.36 microM), three (0.84 +/- 0.31 microM v. 0.47 +/- 0.24 microM) and five (0.66 +/- 0.28 microM v. 0.40 +/- 0.35 microM) days after admission (p < 0.05 in each case). Over 10 days of hospital treatment, mean level of exhaled H2O2 0.45 +/- 0.22 microM in CAP patients with smoking history was decreased if compared with 0.71 +/- 0.19 microM exhaled H2O2 in CAP group (p = 0.005). On the contrary, TBARs concentration evaluated over entire study period was increased in smoking CAP patients (median 0.02 microM, range 0-0.32 microM) compared with non-smoking group (median 0.01 microM, range 0-0.21 microM, p < 0.05). Concurrent, active smoking status was related with the decreased levels of H2O2 exhaled in breath condensate within the course of CAP but it appeared to increase levels of TBARs. CONCLUSIONS: The differential alternations of oxidative parameters in EBC with respect to the smoking status might provide evidence of increased H2O2 decomposition and enhanced generation of reactive species in airways of CAP patients.

Aged↗
PubMed1991

A field method for measuring solvent vapors in exhaled air--application to styrene exposure.

A method is described for measuring solvent vapors in mixed-exhaled air. The subject exhales through a carbon-containing tube connected to a Wright respirometer. Adsorbed vapors are subsequently eluted by carbon disulfide and analyzed by gas chromatography. Twenty-minute exposures to styrene and the corresponding concentrations of styrene in the breath and venous blood were repeatedly measured for two subjects. Regression analyses indicated that the breath measurements were highly correlated with both the exposures and the blood concentrations of styrene. In another study, styrene was measured simultaneously in the mixed-exhaled air by this technique and in the end-exhaled air by a portable gas chromatograph. The mixed-exhaled air obtained with this method contained about half alveolar air. Analysis of the components of the variance obtained from all the data indicated that the error in measurement by this method was about one-fourth of the total variance.

Adult↗
PubMed1989

Wheezing on maximal forced exhalation in the diagnosis of atypical asthma. Lack of sensitivity and specificity.

STUDY OBJECTIVE: To determine whether wheezing on maximal forced exhalation is a predictor of asthma in persons with normal or nearly normal baseline spirometry. DESIGN: Prospective study of patients referred for methacholine challenge testing. SETTING: Pulmonary function laboratory at a hospital. PATIENTS: Forty-four patients referred for methacholine challenge testing because of the clinical suspicion of cough variant or otherwise difficult to diagnose asthma, with normal or nearly normal baseline spirometry and without wheezing on routine lung auscultation during quiet breathing. INTERVENTIONS: We listened for wheezing on maximal forced exhalation. Wheezing was defined as a continuous sound with a musical quality. Methacholine challenge testing was done. The concentration of methacholine required to produce a 20% fall in baseline FEV1 (PC20) of less than 8 mg/mL was considered a positive test for asthma. MEASUREMENTS AND MAIN RESULTS: Wheezing was present on maximal forced exhalation in 8 of 14 patients with a positive methacholine challenge test (sensitivity = 57%) and absent in 11 of 30 patients with a negative test (specificity = 37%). Furthermore, wheezing on maximal forced exhalation was present in 13 of 27 patients with a PC20 greater than 16 mg/mL and absent in 2 of 7 with a PC20 less than 4 mg/mL. CONCLUSIONS: Wheezing on maximal forced exhalation is neither sensitive nor specific for airway hyperreactivity.

Adult↗
PubMed1998

Exhaled nitric oxide and impaired oxygenation in cirrhotic patients before and after liver transplantation.

BACKGROUND: Nitric oxide may be involved in the impaired oxygenation of cirrhotic patients, a condition that improves in most patients after liver transplantation. OBJECTIVE: To compare oxygenation and nitric oxide concentrations before and after liver transplantation. DESIGN: Before-and-after observational study. SETTING: Academic medical center. PATIENTS: 18 patients with cirrhosis and no obvious cardiopulmonary disease who underwent successful orthotopic liver transplantation. INTERVENTION: Orthotopic liver transplantation. MEASUREMENTS: Blood gas analysis, measurement of exhaled nitric oxide, contrast-enhanced echocardiography, and pulmonary function tests. RESULTS: Before transplantation, the mean (+/- SD) exhaled nitric oxide concentration was higher in patients than in normal controls (13 +/- 4.9 parts per billion [ppb] compared with 5.75 +/- 1.9 ppb; P < 0.001). After transplantation, the alveolar-arterial oxygen gradient significantly decreased (from 17.3 +/- 7.1 mm Hg to 9 +/- 5.2 mm Hg; P < 0.001), as did the exhaled nitric oxide concentration (from 13 +/- 4.9 ppb to 6.2 +/- 2.8 ppb; P < 0.001). The decrease in the exhaled nitric oxide concentration was significantly correlated with the decrease in the alveolar-arterial oxygen gradient (r = 0.56; P = 0.014). Five patients met the criteria for the diagnosis of the hepatopulmonary syndrome before transplantation; the syndrome was cured by transplantation. CONCLUSIONS: The correlation between the decrease in exhaled nitric oxide concentration after liver transplantation and the improvement in oxygenation reinforces the hypothesis that nitric oxide is an important mediator of impaired oxygenation in patients with cirrhosis.

Adult↗
PubMedDate not supplied

Exhaling a budesonide inhaler through the nose results in a significant reduction in dose requirement of budesonide nasal spray in patients having asthma with rhinitis.

Budesonide, an inhaled corticosteroid is used routinely in the treatment of bronchial asthma and rhinitis. Although inhaled corticosteroids in therapeutic doses are unlikely to result in systemic side effects, there is as yet skepticism about their routine and prolonged use. The aim of this study was to determine whether budesonide inhalation through a metered dose inhaler, when exhaled through the nose could result in a reduction in the dose requirement of budesonide metered nasal spray in patients having perennial allergic asthma with rhinitis. This study was an open, parallel, comparative, crossover trial in which 49 young patients having perennial allergic asthma with rhinitis were divided into two groups and administered either a combination of budesonide metered dose inhaler with a budesonide nasal spray or a budesonide inhaler alone, which was to be exhaled through the nose. Both groups were later crossed over and weekly symptom scores and peak nasal inspiratory flow rates were monitored during each phase of the study. Finally, patients who volunteered from both groups were instructed to note the reduction in dose requirement of budesonide nasal spray while using a budesonide inhaler and exhaling it through the nose. The results of this study reveal that when a budesonide inhaler is exhaled through the nose, it results in an improvement in symptom scores and peak nasal inspiratory flow rates, which were significantly less than those obtained in the group using both a budesonide nasal spray and a metered dose inhaler. In addition, exhaling budesonide through the nose results in a 40.1% reduction in the dose requirement of a budesonide nasal spray, which is statistically significant (p < 0.001).

Administration, Inhalation↗
PubMed1999

NO in exhaled air is correlated with markers of eosinophilic airway inflammation in corticosteroid-dependent childhood asthma.

The relationship between nitric oxide in exhaled air, levels of sputum eosinophils, sputum eosinophil cationic protein (ECP) and urinary eosinophil protein X (EPX) excretion has not yet been investigated in corticosteroid-dependent childhood asthma. Therefore, taking 25 children with stable asthma (mean age 11.2 yrs) treated with inhaled corticosteroids and nine nonatopic healthy control children (mean age 12.8 yrs) the level of exhaled NO was measured by means of a chemiluminescence analyser before and after sputum induction. This was conducted as a slow vital capacity manoeuvre under standardized conditions with a target flow of 70 mL x s(-1) against a resistance of 100 cm H2O x L(-1) x s. Sputum induction was performed by inhalation of hypertonic saline (3, 4, and 5%) in a standardized manner and a single sample of urine was collected. Exhaled NO (p = 0.01), absolute eosinophil cell counts in sputum (p = 0.02), sputum ECP (p = 0.09) and urinary EPX excretion (p = 0.02) were higher in asthmatics compared to control children. Exhaled NO was positively correlated with sputum ECP (r(s) = 0.59, p = 0.002), urinary EPX (r(s) = 0.42, p = 0.03), and sputum eosinophils (r(s) = 0.30, p = 0.15) in the asthmatic children. These correlations appeared to be pronounced after sputum induction, where NO values had decreased (p = 0.01). None of the correlations were observed in the group of nonatopic control subjects. Additionally there were significant correlations between sputum ECP and sputum eosinophils (r(s) = 0.69, p<0.001) as well as between sputum ECP and urinary EPX excretion (r(s) = 0.58, p = 0.003) in the asthmatics. Exhaled NO provides information about the degree of eosinophilic airway inflammation and thus appears to be a useful and easy-to-perform inflammatory marker in corticosteroid-dependent asthma.

Administration, Inhalation↗
PubMed1999

Analysis of nitric oxide in the exhaled air of patients with chronic glomerulonephritis.

BACKGROUND: Nitric oxide (NO) plays an important role in renal hemodynamics and function. Although production of NO in the glomeruli has been found to be increased in animal models of glomerulonephritis, it remains unclear whether its endogenous production is enhanced in patients with chronic glomerulonephritis (CGN). SUBJECTS AND METHODS: We measured NO output in exhaled air as an indicator of its local production in the lungs and plasma and urinary nitrite plus nitrate (NO2-/NO3-) levels as indicators of its production in the whole body in 21 patients with CGN in 31 healthy controls. RESULTS: The patients exhaled higher concentrations of NO (29.5 +/- 1.4 vs. 18.7 +/- 1.0 parts per billion (ppb), mean +/- SEM, p < 0.0001) and exhaled NO output was also higher than in controls (166.6 +/- 6.8 vs. 95.5 +/- 5.6 nl/min/m2, p < 0.0001). Plasma NO2-/NO3- concentrations were also significantly greater in the patients than in the controls (81.6 +/- 7.2 vs. 41.1 +/- 4.3 micromol/l, p < 0.001). In patients with CGN, exhaled NO output correlated negatively with creatinine clearance (r = -0.62, p < 0.05). Oral administration of prednisolone (60 mg/day) for two weeks did not significantly affect the exhaled NO output in the patients (160 +/- 7 vs. 200 +/- 30 nl/min/m2, p = NS) despite a decrease in urinary protein excretion (12.0 +/- 2.9 vs. 1.4 +/- 0.6 g/day, p < 0.01). CONCLUSION: These findings suggested that endogenous NO production is increased in patients with CGN. Increased endogenous NO production may play some pathophysiological role in these patients.

Administration, Oral↗
PubMed2003

The effect of montelukast on bronchial provocation tests and exhaled nitric oxide levels in asthmatic patients.

BACKGROUND: Leukotriene antagonist therapy in asthmatic patients alleviates symptoms and improves exercise tolerance, however the effect of these drugs on bronchial provocation tests and exhaled nitric oxide levels are less clearly established. OBJECTIVE: To determine the effect of montelukast treatment on airway hyperresponsiveness to exercise, methacholine and adenosine-5'-monophosphate and on exhaled nitric oxide levels in steroid-naive asthmatics. METHODS: Following a 2 week run-in period, 20 mild to moderate asthmatics were enrolled in an open label 6 week trial of oral montelukast-sodium therapy. Bronchial hyperreactivity (exercise, methacholine and adenosine-5'-monophosphate challenges) and exhaled nitric oxide levels were measured before and after the 6 week period. RESULTS: Montelukast treatment resulted in a significant improvement in exercise tolerance: median delta FEV1 20.0% (range 0-50) prior to treatment vs. 15.0% (range 0-50) post-treatment (P = 0.029). A significant difference was also observed for exhaled NO following therapy: median NO 16.0 ppb (range 7-41) vs. 13.0 (range 4.8-26) (P = 0.016). No change was seen in baseline lung function tests (FEV1, MEF50) or in the bronchial responsiveness (PC20) for methacholine and adenosine-5'-monophosphate. CONCLUSIONS: This study demonstrates that the leukotriene antagonist montelukast-sodium reduces bronchial hyperreactivity in response to exercise and reduces exhaled nitric oxide levels but has little effect on bronchial responsiveness to methacholine and adenosine challenges.

Acetates↗
PubMed2004

[Complex assessment of nicotine dependence using questionnaires and measurement of carbon oxide concentration in exhaled air].

AIM: To study nicotine dependence (ND) basing on special questionnaires and measurement of CO concentrations in the exhaled air. MATERIAL AND METHODS: 350 smokers (318 males and 32 females) aged 20-57 years (mean age 37.1 +/- 7.3 years) were studied. ND was assessed by Fagerstrom test (FT), motivation to smoke and to quit tests, smoking history and exhaled CO measurement. In addition, respiratory complaints and ventilation parameters such as peak expiratory flow (PEF) and forced expiratory volume per 1 sec (FEV1) were measured. RESULTS: Mean daily cigarette number was 14.2 +/- 7.3; smoking duration 16.3 +/- 7.8 years and smokers index 170.9 +/- 87.8. Smoking women differed from smoking men in ND, PEF% and FEV1% decline as well as CO level. Exhaled CO was 21.1 +/- 9.5 ppm, on the average, corresponding to moderate dependence. ND and daily cigarette number produced a direct impact on the exhaled CO level. FT findings directly correlated with the number of daily cigarettes and CO level (mean 3.2 +/- 2.3). Among motivation to smoke factors was the demand to release tension. CONCLUSION: ND varies considerably among smokers by severity. Smoking men and women differ considerably by ND. Along with dependence tests, exhaled CO measurement provides objective verification of ND.

Adult↗
PubMed1991

Exhalation of metallic mercury by acatalasemic, hypocatalasemic and normal mice exposed to metallic mercury vapor.

In order to elucidate the amounts of metallic mercury exhaled from mice having different amounts of catalase activity, normal, homozygous hypocatalasemic and acatalasemic mice were exposed to radioactive metallic mercury vapor at three levels of concentrations (0.072, 0.144, and 0.297 mg/m3). The timed and cumulative amounts of metallic mercury exhaled from the mice were used to classify them, in the descending order, as being acatalasemic, hypocatalasemic, and normal at the three environmental mercury concentrations. The statistical differences in the mean values among the acatalasemic, hypocatalasemic, and normal mice were calculated by the use of one-way ANOVA and multiple comparison of the mean values by Tukey's method. The mean values of the timed amounts of exhaled metallic mercury were found to be significantly different (P less than 0.05) among the three kinds of mice several hours after exposure, and those of the cumulative amounts of exhaled metallic mercury were in the descending order of acatalasemic, hypocatalasemic and normal mice, and were significantly different among the three types of mice almost over the entire time course. Thus, negative correlation coefficients were obtained between the logarithms of the catalase activity in the lungs and the blood, and the logarithms of the cumulative amounts of exhaled metallic mercury.

Acatalasia↗
PubMed1984

Quantitative measurement of the exhalation rate of volatile N-nitrosamines in inhalation experiments with anaesthetized Sprague-Dawley rats.

Volatile N-nitrosamines have been detected in the human environment--in work places, such as the rubber, leather and chemical industries, in tobacco smoke and also inside new cars. In order to make risk assessments on the basis of inhalation experiments with animals at dose levels relevant to the human situation, it is important to know the actual absorption rate in the respiratory tract. In this study, 63 female Sprague-Dawley rats were exposed to four nitrosamines (N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosopyrrolidine and N-nitrosomorpholine) in air. Respiratory parameters were monitored by pneumotachography. After 10 min of inhalation, the exhaled air was collected for 10 min in steps of 2 min intervals and analysed for its content of nitrosamines with a Thermal Energy Analyzer. Inhalation and exhalation were maintained by endotracheal intubation under narcosis with Thalamonal. The influence of this anaesthetic on the urinary excretion of N-nitrosodimethylamine after gavage and inhalation was tested: in comparison with unanaesthetized animals and with a group under ether narcosis, the excretion of the nitrosamine by the Thalamonal-anaesthetized animals was drastically reduced (factor of 20 to 60). Independent of the concentration of inhaled nitrosamine, ranging from 1-450 micrograms/L in air, the relative amounts of exhaled substance 10 min after inhalation were 0.9% N-nitrosodimethylamine, 0.4% N-nitrosodiethylamine, 6% N-nitrosopyrrolidine and 5% N-nitrosomorpholine. Extrapolation of these data back to the first exhalation (i.e., following the last inhalation) revealed that a remarkable amount of substance may be exhaled (up to 30% N-nitrosodimethylamine).

Air Pollutants↗
PubMed1997

Pentoxifylline attenuates LPS-induced bronchial hyperresponsiveness but not the increase in exhaled nitric oxide.

BACKGROUND: Inhaled endotoxin (LPS) may cause a transient increase in airway responsiveness, possibly through a cytokine-mediated airway inflammation, which is associated with an increase in nitric oxide synthesis and release. OBJECTIVE: We wondered whether pentoxifylline (PTX), which may attenuate cytokine release induced by LPS, could inhibit LPS-induced increase in airway responsiveness. METHODS: Methacholine (Mch) bronchial responsiveness was assessed 2 and 24 h after saline or LPS inhalation in eight subjects with bronchial hyperresponsiveness (PD20FEV1 610 +/- 53 micrograms), treated with iv saline or PTX, in a double-blind crossover design. Nitric oxide (NO) in the exhaled air, which was expected to increase after LPS inhalation, and PEFR values were also measured at baseline, hourly for 6 h and 24 h later. RESULTS: After LPS inhalation PEFR decreased significantly compared with placebo inhalation, reaching a maximum decrease of 11.25 +/- 1.05 and 4.5 +/- 0.84% of baseline, at 2 h, respectively during saline and PTX infusion, P < 0.001. Exhaled NO were elevated after LPS compared with placebo inhalation at 1 h (35.6 +/- 4.8 vs 18 +/- 2.8 ppb, P < 0.001), with no difference during saline or PTX infusion. Exhaled NO remained elevated until the 6th hour. PD20FEV1 2h after LPS inhalation was significantly lower than after placebo inhalation both during saline infusion (234 +/- 29 vs 625 +/- 62 micrograms, P < 0.001) and during PTX infusion (441 +/- 47 vs 616 +/- 48 micrograms, P < 0.001), the difference between saline and PTX being significant (P < 0.01). At 24 h no difference in PEFR, PD20FEV1 and exhaled NO was observed in comparison with pre-study values. CONCLUSION: PTX attenuates both the decrease in airway patency and the increase in bronchial responsiveness induced by LPS inhalation, without any significant change in exhaled NO, which is increased by LPS inhalation.

Adult↗
PubMed1997

Increased nitric oxide in exhaled air of patients with systemic lupus erythematosus.

OBJECTIVE: In experimental animals, elevated nitric oxide (NO) production has been implicated in the pathogenesis of a lupus-like syndrome. Abnormalities of lung function tests are reported in a high proportion of patients with systemic lupus erythematosus (SLE). We investigated whether NO output in exhaled air might be increased in patients with SLE and whether it is related to disease activity and to respiratory function abnormalities. METHODS: Lung volume, maximal expiratory flow at 50 and 25% of vital capacity (MEF50 and MEF25), diffusion coefficient for carbon monoxide (KCO), and NO in the exhaled air were measured in 27 outpatients with SLE (23 women, age 39.2 +/- 16.3). NO in exhaled air was also measured in 30 healthy control subjects. Disease activity was assessed by the European Consensus Lupus Activity Measurement (ECLAM) scoring system. RESULTS: Mean values of peak concentrations of NO exhaled air were 64.8 +/- 27.9 parts per billion (ppb) in patients and 31.6 +/- 7.7 ppb in controls, p < 0.001. Peak NO concentration was directly related to ECLAM activity score (p < 0.05) and inversely related to MEF25 (p < 0.05). CONCLUSION: NO in exhaled air is significantly increased and correlated with disease activity in patients with SLE. Whether increased NO output depends on respiratory tract inflammation, as the relationship with MEF25 may suggest, or on circulating cytokines produced elsewhere remains to be investigated.

Adolescent↗
PubMed1999

Increased excretion of nitric oxide in exhaled air of patients with chronic renal failure.

Nitric oxide exerts multiple effects on renal function. It remains unclear whether endogenous nitric oxide production is increased or decreased in patients with chronic renal failure. To evaluate endogenous nitric oxide production in these patients we studied exhaled nitric oxide output by an ozone chemiluminescence method and plasma NO2(-)/NO3(-) levels by the Griess method in 40 patients with end-stage chronic renal failure who underwent regular continuous ambulatory peritoneal dialysis (n=30) or haemodialysis (n=10), and in 28 healthy subjects. Patients with chronic renal failure had a higher exhaled nitric oxide concentration [39+/-3 versus 19+/-1 parts per billion, (mean+/-S.E.M.), P<0.0001], a greater nitric oxide output (177+/-11 versus 96+/-7 nl.min-1.m-2, P<0.001) and a higher plasma NO2(-)/NO3(-) concentration (96+/-14 versus 33+/-4 micromol, P<0.01) than controls. These values did not differ between patients on haemodialysis and those on continuous ambulatory peritoneal dialysis. Patients with chronic renal failure had significantly higher plasma concentrations of both interleukin-1beta and interferon-gamma than controls. The exhaled nitric oxide output did not correlate with plasma NO2(-)/NO3(-) or with peritoneal dialysate NO2(-)/NO3(-), but plasma NO2(-)/NO3(-) correlated with dialysate NO2(-)/NO3(-) in patients who underwent continuous ambulatory peritoneal dialysis (r=0.77, P<0.01). Haemodialysis for 4 h acutely decreased plasma NO2(-)/NO3(-) (92+/-17 versus 50+/-8 micromol, P<0.05) and cGMP concentration (16.5+/-4.3 versus 5.1+/-1. 7 pmol/ml, P<0.01), but did not decrease exhaled nitric oxide output. The increase in exhaled nitric oxide with the simultaneous increase in circulating cytokines suggests that nitric oxide synthase seems to be induced significantly in patients with chronic renal failure. Increased endogenous nitric oxide production may have a pathophysiological role in patients with uraemia.

Analysis of Variance↗
PubMed2004

Ion trap liquid chromatography/tandem mass spectrometry analysis of leukotriene B4 in exhaled breath condensate.

The objective of this study is the measurement of leukotriene B7 (LTB4), a potent inflammatory mediator, in exhaled breath condensate by using liquid chromatography/mass spectrometry (LC/MS and LC/MS/MS). Condensation of exhaled breath is a non-invasive method to collect airway secretions. Deuterated (d4)-LTB4 was used as internal standard. The MS and MS/MS behavior of LTB4 and LTB4-d4 was studied by electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in both positive and negative ion polarity mode. Preliminary results show that monitoring negative ions in ESI mode has the best sensitivity for both LTB4 and LTB4-d4. Therefore, negative ESI was chosen, and the [M-H]- ions at m/z 335 and 339 were selected for quantification. The lower limit of quantification for LTB4, expressed as the lowest point of the calibration curve, was 100 pg/mL. Using this technique, we measured LTB4 in exhaled breath condensate in two healthy subjects, four asthmatic patients on anti-inflammatory treatment, and four asthmatic patients who were not on anti-inflammatory drugs. Exhaled LTB4 concentrations were detected only in asthmatic patients who were not on anti-inflammatory therapy. This method is potentially useful for non-invasive assessment of airway inflammation, but the sensitivity of the technique needs to be improved.

Adolescent↗
PubMed2006

Carbon dioxide exhalation temporarily increases during electroconvulsive therapy.

Electroconvulsive therapy induces hypermetabolism and elevates oxygen and energy demands, while more carbon dioxide is produced than usual. The purpose of the present study was to determine the elevated carbon dioxide exhalation and the adequate ventilation volume during electroconvulsive therapy. Carbon dioxide exhalation during an electrically induced seizure was continuously monitored by capnography and spirography in 15 patients with endogenous depression. A laryngeal mask airway was used to measure the airway gas flow. Data were collected during a total of 80 electroconvulsive therapy trials. The carbon dioxide exhalation at 1 min after electrical stimulation was higher than the control value (2.8 +/- 0.4 versus 2.3 +/- 0.3 ml.min(-1).kg(-1), mean +/- SD; P < 0.05). The ventilation volume was increased for 3 min after the electrical stimulation to maintain the end-tidal carbon dioxide partial pressure at 35-40 mmHg. The results showed that increasing the ventilation volume by approximately 20% may be necessary to compensate for the increased carbon dioxide exhalation during electroconvulsive therapy.

Adult↗
PubMed2006

A comparison of exhaled nitric oxide measurements performed using three different analysers.

INTRODUCTION: Exhaled nitric oxide (NO) is an established technique for monitoring airway inflammation. We have compared exhaled NO measurements from 3 different analysers; Ecomedics (E), Niox (N) and Logan (L). METHODS: Thirty subjects (10 non-smoking healthy subjects, 10 non-smoking patients with asthma and 10 ex-smoking COPD patients) performed 3 repeated measurements of exhaled NO at a flow rate of 50 ml/s on each of the 3 analysers. Within analyser variability was determined by calculating the repeatability coefficient for each analyser. Differences between analysers were assessed by (1) the differences between group means and (2) the Bland Altman method to estimate the variability expected for an individual using the 3 analysers. RESULTS: The repeatability coefficients (expressed as ratios) were 1.12, 1.19 and 1.19 for N, E and L, respectively. There were significant differences (P<0.05) between analysers; the Logan analyser gave the highest group mean values and Ecomedics gave the lowest group mean values. Differences between analysers were observed in all subject groups (healthy, asthma, COPD). Similar results were obtained in the 3 groups when analysed separately. Bland Altman analysis gave the following ratios [data are mean ratio (95% limits of agreement)]; N:E 1.59 (1.02-2.50), L:N 1.23 (0.72-2.13), L:E 1.96 (1.09-3.57). CONCLUSION: Our findings indicate that exhaled NO measurements in healthy subjects and patients with airways disease differ according to the type of analyser used.

Adult↗