Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Exhalation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources
PubMed1996

Oxidation of D(-)3-hydroxybutyrate administered to rats with extensive burns.

Although the suppressive effect of 3-hydroxybutyrate (3-OHB) on post-traumatic protein catabolism in traumatized patients is well documented, the oxidation of exogenously administered 3-OHB during catabolic stress has not been investigated. The present study was designed to evaluate, using radioactive isotopes, total body oxidation in rats with and without burn stress to which 3-OHB had been exogenously administered, in comparison with total body oxidation in such rats that had received glucose. The rats were divided into four groups, based on whether or not a 30% full-thickness burn was inflicted, and the type of infusate they received after the burn, namely, 3-OHB or glucose. The total exhaled CO2 was collected for 6h after the infusion was commenced, and 14CO2 was assayed in a liquid scintillation spectrometer. Oxidation of the infusate was calculated from the percentage of exhaled 14CO2 derived from the infused substrates. The plasma concentration of 3-OHB was significantly increased after the infusion in both the burned and non-burned rats. The total exhaled 14CO2 from the rats infused with glucose decreased from 48.2 +/- 2.4% to 40.8 +/- 3.7% (means +/- SD, P < 0.001) after thermal injury. However, the total exhaled 14CO2 from the rats infused with 3-OHB appeared sooner, and there was no difference in the total expired 14CO2 derived from 3-OHB between the burned and non-burned rats, at 68.1 +/- 2.7% vs 66.4 +/- 3.4%, respectively. These findings suggest that even under conditions of burn stress, 3-OHB can be oxidized normally if the plasma concentration of 3-OHB is elevated by exogenous administration.

3-Hydroxybutyric Acid↗
PubMed1983

Quantitative evaluation of ethane and n-pentane as indicators of lipid peroxidation in vivo.

The use of exhalation of ethane and n-pentane in experimental animals as parameters of lipid peroxidation led to an examination of pharmacokinetics of both compounds in rats. When rats were exposed, in a closed desiccator jar chamber, to a wide range of ethane concentrations, linear elimination pharmacokinetics were observed. n-Pentane, when concentrations higher than 100 ppm were applied, displayed saturation kinetics. These were formally explained by action of two competing metabolizing pathways or enzymes. Application of preexisting models could describe exhalation of both ethane and n-pentane by untreated control rats. Stimulation of lipid peroxidation by ferrous ions or by carbon tetrachloride resulted in dissimilar quantitative behaviours of ethane and n-pentane. Ethane production rates were enhanced after application of both compounds. Because of relatively slow metabolic eliminations this led to markedly elevated concentrations of ethane in the gas phase of the system. Pentane production rates were simultaneously enhanced. However, difficulties in interpretation arise because of rapid metabolic elimination of n-pentane. Compounds that diminish pentane metabolism are shown to evoke higher pentane concentrations in the system than compounds which only enhance the pentane production rate. Determinations of ethane exhalation should provide a more favourable parameter of lipid peroxidation than exhalation of pentane.

Animals↗
PubMed1984

Metabolism of methylazoxymethanol acetate in the F344 rat and strain-2 guinea pig and its inhibition by pyrazole and disulfiram.

The basic parameters of the metabolism of methylazoxymethanol-(N,N'-methyl-14C) acetate, in terms of exhaled 14CO2, urinary metabolites, and inhibition by pyrazole and disulfiram, were examined in F344 rats and strain-2 guinea pigs. After a 18.7 mg/kg SC dose, 45% (6 h) and 49.5% (24 h) was exhaled as 14CO2, and 6.6% (24 h) of the radioactivity was excreted in the urine by the rats. After identical treatment, 36.5% (6 h) and 39.5% (24 h) was exhaled as 14CO2 and 3.5% (24 h) was excreted in the urine by the guinea pigs. Urea-14C and methylazoxymethanol(-14C) were the major urinary metabolites. In both species, pretreatment with pyrazole (40 or 360 mg/kg, IP) caused a significant reduction of exhaled 14CO2 and an increase in the amount of urinary methylazoxymethanol(-14C). Similar but less pronounced effects were observed after pretreatment of rats with disulfiram (1 g/kg, PO). These results are discussed with respect to possible enzyme systems involved in the metabolic activation of methylazoxymethanol in vivo.

Alcohol Dehydrogenase↗
PubMed1994

[No inhibition of intestinal motility following ketamine-midazolam anesthesia. A comparison of anesthesia with enflurane and fentanyl/midazolam].

Postoperative intestinal atonia is a complication which is likely to occur in patients predisposed for constipation and in patients after intra-abdominal operations. The postoperative delay of bowel movement, however, is often also related to the type of anaesthesia being used. In order to evaluate the magnitude of an anaesthetic-induced postoperative delay of bowel movement, two types of intravenous-based anaesthesia using fentanyl/midazolam (1 mg/25 mg; dosage 0.1 ml/kg/h), and ketamine/midazolam (250 mg/25 mg; dosage 0.1 ml/kg/h) respectively were compared with a volatile anaesthetic technique (enflurane; mean concentration 1.5 vol%). METHODS. In three groups of patients (each n = 15) undergoing elective surgery of the lower extremities, induction of anaesthesia was accomplished with methohexital (1-1.5 mg/kg) to facilitate intubation. For the maintenance of muscle relaxation vecuronium bromide was used. All patients were given droperidol to prevent postoperative emesis, and they were artificially ventilated with N2O/O2 (60:40) to normal end-expiratory CO2 concentrations. No anticholinergic agents were used at the end of operation since they are known to interfere with bowel motility. In order to determine gastro-intestinal motility, the H2 exhalation test was used. For this purpose 40 g lactulose in 100 ml of water was given to all patients via a gastral tube shortly before extubation. Lactulose is broken down by bacteria once it enters the colon, and H2 is released, taken up by the vascular system and exhaled. Postoperatively, patients were asked to exhale into a 20-ml syringe every 10 min. The content was analysed for hydrogen (ppm), using an electrochemical sensor (GMI exhaled hydrogen monitor). From the time of lactulose instillation to a threefold increase in end-expiratory hydrogen concentration (compared to the preoperative value), gastro-coecal transit time was computed. RESULTS. All three groups of patients were comparable in age, height and body weight. Also, the duration of operation was comparable in all three groups. Mean gastro-coecal transit time was 204 (+/- 19.6, SD) min following enflurane, 302 (+/- 32.8 SD) min following fentanyl/-midazolam and 210 (+/- 28.8 SD) min following ketamine/midazolam anaesthesia. The gastro-intestinal inhibition after the opioid-based anaesthetic technique was significantly prolonged (p < 0.001, Kruskal-Wallis test). There was no significance between patients after ketamine-based anaesthesia and those who had the volatile anaesthetic. DISCUSSION AND CONCLUSION. When using intravenous anaesthesia with an opioid, gastro-intestinal inhibition, especially in patients prone to have constipation, is likely to develop postoperatively. In classical neuroleptanaesthesia and in analgosedation in the ICU, the simultaneous use of the butyrophenone droperidol seems to counteract the inhibition of opioid-related gastrointestinal motility. In cases of opioid-related gastrointestinal atonia a gastrokinetic compound may be necessary to overcome this effect on intestinal motility.

Adult↗
PubMed1999

Biokinetics and radiation doses for carbon-14 urea in adults and children undergoing the Helicobacter pylori breath test.

The long-term biokinetics and dosimetry of carbon-14 were studied in nine adults and eight children undergoing carbon-14 urea breath test for Helicobacter pylori (HP) infection. The elimination of 14C via exhaled air and urine was measured with the liquid scintillation counting technique and with accelerator mass spectrometry. After the subjects had been given 110 kBq 14C-urea (children: 55 kBq) orally, samples of exhaled air were taken up to 180 days after administration and samples of urine were collected up to 40 days. Sixteen of the subjects were found to be HP-negative. In these subjects a total of 91.1%+/-3.9% (mean of adults and children +/- standard error of the mean) of the administered 14C activity was recovered. The majority of the administered activity, 88.3%+/-6.2% in adults and 87.7%+/-5.0% in children, was excreted via the urine within 72 h after administration. A smaller fraction was exhaled. In adults 4.6%+/-0.6% of the activity was exhaled within 20 days and in children 2.6%+/-0.3%. Uncertainties in the biokinetic results are mainly due to assumptions concerning endogenous CO2 production and urinary excretion rate and are estimated to be less than 30%. The absorbed dose to various organs and the effective dose were calculated using the ICRP model for urea and CO2. The urinary bladder received the highest absorbed dose: in adults, 0.15+/-0.01 mGy/MBq and in children of various ages (7-14 years), 0.14-0.36 mGy/MBq. The findings indicate that an investigation with 14C-urea gives an effective dose to adults of 2.1+/-0.1 microSv (for 110 kBq) and to children of 0.9-2.5 microSv (for 55 kBq). From a radiation protection point of view, there is thus no reason for restrictions on even repeated screening investigations with 14C-urea in whole families, including children.

Adolescent↗
PubMed2001

High levels of nitric oxide in individuals with pulmonary hypertension receiving epoprostenol therapy.

Lack of vasodilator substances, such as nitric oxide (NO), has been implicated in the development of pulmonary hypertension, but the pathogenesis of the disease remains speculative. We hypothesized that NO plays a role in the pathogenesis of primary pulmonary hypertension (PPH), and may serve as a sensitive and specific marker of disease progression and/or severity. To test this, exhaled NO and pulmonary artery pressure were measured in individuals with PPH and secondary pulmonary hypertension (SPH) on various therapies, including the potent vasodilator epoprostenol (prostacyclin), compared with healthy controls. NO in exhaled breath of individuals with PPH was lower than SPH or control (p<0.05). In contrast, exhaled NO of individuals with PPH or SPH receiving epoprostenol was strikingly higher than PPH or SPH individuals not receiving epoprostenol, or controls. Concomitant with higher NO levels, right ventricular systolic pressure of individuals significantly decreased with epoprostenol. Importantly, in paired measures of exhaled NO before and after epoprostenol, NO increased in all pulmonary hypertensive individuals 24 h after initiation of epoprostenol therapy (p<0.05). NO may be a useful noninvasive marker of pulmonary hypertension severity and response to prostacyclin therapy.

Adolescent↗
PubMed1999

Acute symptoms during non-inhalation exposure to combinations of toluene, trichloroethylene, and n-hexane.

OBJECTIVES: To study the acute effect of exposure to a mixture of three commonly used solvents in humans using a route of exposure not involving the nose and lungs, in this case a gastrointestinal application. METHODS: In a 2(3)-factorial experiment eight healthy male volunteers were exposed to the eight combinations of toluene (1. 5 and 4 mg. min(-1)) trichloroethylene (1.5 and 4 mg. min(-1)), and n-hexane (0.3 and 1.0 mg. min(-1)) for 60 min given into the stomach via a feeding tube. The body burden was measured by the exhaled solvent concentrations and the urinary excretion of metabolites during and after exposure. The subjective ratings of tiredness, sleepiness, headache, nausea, feeling of intoxication, and dizziness were estimated by continuous linear analogue rating scales before and 30, 90, and 240 min after the start of exposure. RESULTS: Concentrations of the three solvents in the end exhaled air varied between 0 and 46 mg. min(-3). The ratings of symptoms were generally low and there was no difference between the high and low doses. Neither was there any correlation between the concentration of solvents in the exhaled air and the ratings. CONCLUSIONS: The study show no effects at levels in end exhaled air of mixtures of solvents which in inhalation studies have given signs of a possible neurotoxic effect. The lack of symptoms using this alternative route supports the hypothesis that "neurotoxic" symptoms in relation to exposure to very low air concentrations of solvents are mainly indirect, mediated by irritation or smell.

Adult↗
PubMed2001

Effects of age, gender, bolus volume, and trial on swallowing apnea duration and swallow/respiratory phase relationships of normal adults.

The effects of age, gender, bolus volume, and trial on swallowing apnea duration (SAD) and swallow/respiratory phase relationships were examined. Sixty adults, composed of ten males and ten females in each of three age groups (i.e., 20-39, 40-59, and 60-83 years), participated. SAD was assessed via nasal airflow during saliva swallows and 10-, 15-, 20-, 25-mL bolus volumes across three trials. Results revealed SAD is consistent across trial (p > 0.05). Significant main effects of age, gender, and bolus volume were found (p < 0.05), i.e., elderly adults had longer SAD than young and middle-aged adults; women had longer SAD than men; and SAD increased as bolus volume increased. With respect to saliva swallows, a significant interaction of age by gender was found (p < 0.05), i.e., males exhibited a decrease in SAD with increasing age while females exhibited an increase in SAD with increasing age. Concerning swallow/respiratory phase relationships, the pattern of exhale-swallow-exhale was evident during 62% of participants' swallows. Furthermore, age, gender, or bolus volume did not predict the pattern of exhale-swallow-exhale (p > 0.05).

Age Factors↗
PubMed1981

Panting in dogs: paths of air flow in response to heat and exercise.

Panting is the major avenue of evaporative cooling in dogs exposed to heat and/or exercise. We found modulation of evaporation was achieved by varying the paths of airflow during inhalation and exhalation. The direction of airflow through the nose and mouth was determined by measuring pressure changes and temperature at the openings of one nostril and the mouth in three dogs (av. weight 22 kg). Rates of oxygen consumption and respiratory evaporation were measured simultaneously. Three patterns of panting were observed as the demand for respiratory evaporation increased: (I), inhalation and exhalation through nose; (II), inhalation through nose, exhalation through nose and mouth; and (III), inhalation through nose and mouth, exhalation through nose and mouth. Pattern I was observed in resting dogs when ambient temperature was below 26 degrees C and when animals ran at slow speeds in the cold (e.g. 0.8 m . s(-1) at 10 degrees C). Patterns II and III were observed when dogs rested quietly at ambient temperatures above 30 degrees C and during exercise except when dogs ran slowly at very low temperatures. Patterns II and III rarely occurred independently for long periods of time. Instead, there was normally a continual oscillation between the two. The proportion of the time that the dog used Pattern III instead of Pattern II increased as temperature and/or speed were increased; but the correlation between rate of respiratory evaporation and the percentage of time Pattern III was utilized was weak (r2=0.63).

Animals↗
PubMed1985

Nasal heat exchange in a northern ungulate, the reindeer (Rangifer tarandus).

When reindeer were exposed to low ambient temperatures, heat and water were recovered from the exhaled air by a nasal counter-current heat exchanger. Measurements of respiratory frequency, minute volume, exhaled air temperature and metabolic rate were made over a range of ambient air temperatures extending from -5.5 degrees C to 27.2 degrees C. At ambient air temperatures less than 10 degrees C the exhaled air temperatures were an average of 21 degrees C less than body temperature. The reduction of the exhaled air temperature at the lowest ambient air temperatures used in this study resulted in the recovery of 75% of the heat added and 80% of the water added to the inspired air on its way to the lungs. The heat and water recovered by the nasal temporal counter-current heat exchanger in reindeer significantly reduced the metabolic cost of survival during cold exposure.

Animals↗
PubMed1986

Influence of lung volume on the mixing defect for an inert gas.

UNLABELLED: For quantitative assessment of how gas mixing in the lung compares to the ideal of perfect mixing, it is necessary to measure pre-inspiratory lung volume as well as to study the inhaled and exhaled gas. Normal young-adult persons in the seated position assumed various lung volumes and then took 1-L test breaths (11% Ar, 22% O2 in N2). Integration of concentration at the mouth against volume yielded amounts of Ar inhaled, exhaled and retained; un-exhaled concentration in the lung after the single breath was calculated from amount retained divided by lung volume (measured by rebreathing). Retention was 60% of the inhaled amount when pre-inspiratory volume was above FRC and less when it was below. Series dead space increased with lung volume. End-tidal Ar was the same as, or slightly above, the concentration predicted for perfect mixing and un-exhaled Ar was slightly below the perfect-mix concentration. INTERPRETATION: three separable influences decrease the transfer of inspirate to the resident gas. A dilution effect, predictable from the volumes involved, decreases retention at low lung volumes. An enlarged series dead space decreases retention at high volumes. In normal persons, a mixing defect that is attributable to poor distribution or incomplete gas-phase diffusion is small and can be ascribed almost completely to the part of the expirate that gives rise to the slope of the alveolar plateau, except when breaths are taken at very low lung volumes.

Adult↗
PubMed1992

Thermodilution cardiac output: comparison between automated and manual injection of indicator.

In clinical practice, cardiac output (CO) is usually reported as the average of thermodilution determinations with injection of the thermal indicator performed at end-exhalation. However, an average of multiple determinations with injections equally dispersed throughout the respiratory cycle has been shown to provide the best estimate of mean CO. This study sought to determine the reproducibility of CO determinations obtained with manual injections of indicator solution performed at end-exhalation, compared with those determined by computer-controlled injections equally dispersed throughout the breathing cycle of 27 patients undergoing cardiac operations. Mean CO was calculated by averaging the four determinations obtained with each technique before induction of anesthesia, after induction of anesthesia, after sternotomy, after cardiopulmonary bypass, and after sternal closure. A total of 130 pairs of mean CO estimations were obtained with manual and automated injections. Mean CO values obtained with manual injections were significantly lower than those obtained with the dispersed injection technique (5.0 +/- 1.4 L/min vs 5.3 +/- 1.6 L/min, P = 0.002). The bias between CO values measured with the manual technique was -0.25 +/- 0.47 L/min lower than those obtained with the dispersed technique. The mean relative bias for the group was 7 +/- 18% with 95% confidence intervals of +/- 26%. During mechanical ventilation, the thermodilution technique with manual injection of indicator solution significantly underestimated CO. Variability in the manual injection technique and inappropriate representation of the mean CO by injections timed to occur at end-exhalation contributed to the disparity. These results indicate that the manual technique of determining CO at end-exhalation may not accurately reflect the average CO.

Anesthesia, General↗
PubMed2004

Diagnostic potential of breath analysis--focus on volatile organic compounds.

Breath analysis has attracted a considerable amount of scientific and clinical interest during the last decade. In contrast to NO, which is predominantly generated in the bronchial system, volatile organic compounds (VOCs) are mainly blood borne and therefore enable monitoring of different processes in the body. Exhaled ethane and pentane concentrations were elevated in inflammatory diseases. Acetone was linked to dextrose metabolism and lipolysis. Exhaled isoprene concentrations showed correlations with cholesterol biosynthesis. Exhaled levels of sulphur-containing compounds were elevated in liver failure and allograft rejection. Looking at a set of volatile markers may enable recognition and diagnosis of complex diseases such as lung or breast cancer. Due to technical problems of sampling and analysis and a lack of normalization and standardization, huge variations exist between results of different studies. This is among the main reasons why breath analysis could not yet been introduced into clinical practice. This review addresses the basic principles of breath analysis and the diagnostic potential of different volatile breath markers. Analytical procedures, issues concerning biochemistry and exhalation mechanisms of volatile substances, and future developments will be discussed.

Air↗
PubMed2006

Airway inflammation assessed by invasive and noninvasive means in severe asthma: eosinophilic and noneosinophilic phenotypes.

BACKGROUND: Airway inflammation assessed by bronchial biopsies demonstrates distinct eosinophilic and noneosinophilic phenotypes in severe asthma, but their relationship to other biomarkers of disease (induced sputum and nitric oxide [NO]) is not clear. OBJECTIVES: We sought to compare airway inflammation using noninvasive (induced sputum, exhaled NO), and invasive (bronchial biopsies) methods in moderate and severe asthma and to assess whether induced sputum and exhaled NO would allow the identification of eosinophilic and noneosinophilic phenotypes in severe asthma. METHODS: We performed a cross-sectional study of 32 subjects with severe asthma and 35 subjects with moderate asthma, from whom we obtained bronchial biopsies, induced sputum, and exhaled NO measurements. RESULTS: Among subjects with severe asthma, we identified eosinophilic and noneosinophilic phenotypes using both bronchial biopsies and sputum cell counts. However, the vast majority of subjects with high sputum eosinophil counts did not have high mucosal eosinophil counts. Exhaled NO was increased in the eosinophilic phenotype as judged from bronchial biopsy findings, but not on the basis of induced sputum. Subjects with high sputum eosinophil counts experienced more asthma exacerbations than the subjects with low sputum eosinophil counts. In contrast, we did not find any differences in the clinical characteristics between eosinophilic and noneosinophilic phenotypes that were identified by bronchial biopsies. CONCLUSION: The use of sputum cell counts allowed the identification of a subgroup of subjects with severe asthma who were at risk of more frequent asthma exacerbations. CLINICAL IMPLICATIONS: Monitoring sputum eosinophil counts in subjects with severe asthma may allow identifying the subjects with the greatest disease activity.

Asthma↗
PubMed2004

Nitric oxide formation in the oropharyngeal tract: possible influence of cigarette smoking.

Cigarette smoking reduces the level of nitric oxide (NO) in exhaled air by an unknown mechanism. The view that part of the effect of cigarette smoking on NO production should occur in the oropharyngeal tract is supported by several studies. We have therefore compared smokers and non-smokers regarding non-enzymatic formation of NO from nitrite in the oral cavity since this is a primary candidate target for cigarette smoke. We have also looked at NO synthase-dependent NO formation in the mucosa of the oropharyngeal tract as an alternative target for the inhibitory effect induced by cigarette smoke. Smokers exhaled 67% lower levels of NO than controls (p<0.01, n=15 each group). We could not detect any significant difference in salivary nitrite, nitrate or ascorbate between smokers and non-smokers. Mouthwash with the antibacterial agent chlorhexidine reduced salivary nitrite (-65%) and exhaled NO levels (-10%) similarly in the two groups. Immunohistochemical techniques revealed dense expression of inducible (but not endothelial or neuronal) NO synthase in the squamous epithelium of non-inflamed tonsillar and gingival tissue biopsies. In the same biopsies, significant Ca2+ -independent citrulline-forming activity was detected. We found no difference between smoking and non-smoking subjects regarding NO-synthase expression and in vitro activity. In another group of non-smoking subjects (n=10), spraying the oropharyngeal tract with the NO-synthase inhibitor NG-monomethyl-L-arginine (250 mg) significantly reduced exhaled NO levels for at least 30 min (-18%, p<0.01). Our data suggest that cigarette smoking does not affect non-enzymatic NO formation from nitrite in saliva. However, NO is also formed by inducible NO synthase in the squamous epithelium of the normal oropharyngeal tract. We suggest that cigarette smoking may down-regulate enzymatic NO formation in the oropharyngeal compartment as well as in the bronchial compartment.

Adult↗
PubMed2005

Non-invasive biomarkers of pulmonary damage and inflammation: Application to children exposed to ozone and trichloramine.

To date, airways injury or inflammation caused by air pollutants has been evaluated mainly by analysis of bronchoalveolar lavage, an invasive technique totally unsuitable to children. The assessment of respiratory risks in this particularly vulnerable population has thus for a long time relied on spirometric tests and self-reported symptoms which are relatively late and inaccurate indicators of lung damage. Research in the field of biomarkers is now opening new perspectives with the development of non-invasive tests allowing to monitor inflammation and damage in the deep lung. Blood tests measuring lung-specific proteins (pneumoproteins) such as Clara cell protein (CC16) and surfactant-associated proteins (A, B or D) are now available to evaluate the permeability and/or the cellular integrity of the pulmonary epithelium. The application of these tests to children has recently led to the discovery of a lung epithelium hyperpermeability caused by trichloramine (nitrogen trichloride), an irritant gas contaminating the air of indoor-chlorinated pools. Serum CC16 can also serve to detect increases of airway permeability during short-term exposures to ambient ozone. Indicators measurable in exhaled air such as nitric oxide (NO) appear more useful to detect airway inflammation. By applying the exhaled NO test to children attending summer camps, we recently found that ambient ozone produces an acute inflammatory response in children from levels slightly lower than current air quality guidelines. In a study exploring the links between atopy, asthma, and exposure to chlorination products in indoor pools, we also found that the exhaled NO test can serve to detect the chronic airway inflammation associated with excessive exposure to trichloramine. Lung-specific proteins measurable in serum and markers in exhaled air represent sensitive tools that can be used to assess non-invasively the effects of air pollutants on the respiratory tract of children.

Biomarkers↗
PubMed1997

Nitric oxide production during exercise in chronic heart failure.

In chronic heart failure (CHF), the ventilatory response is increased compared with normal. This response is, in part, caused by reduced perfusion to ventilated lung. Nitric oxide (NO) is a potent vasodilator and may have an important role in pulmonary vasodilatation during exercise. NO is present in exhaled air. The amount of NO in exhaled air, when breathing NO-free compressed air, is known to increase in normal subjects during exercise. In this study, we quantified NO output in exhaled air in patients with CHF during exercise. Six patients with CHF (New York Heart Association Class II and III; two with dilated cardiomyopathy, three with ischemic heart disease, and one with hypertensive heart disease) and six normal subjects were studied with a symptom-limited incremental exercise test on a cycle ergometer. Oxygen uptake (VO2), carbon dioxide output (VCO2), and minute ventilation (VE) were measured breath by breath with a mass spectrometer, flow meter, and computer. The NO concentration was continuously measured in mixed expired air by chemiluminescence. Peak exercise work rate was lower in patients with CHF than in normal subjects (71.3 +/- 41.6 W vs 257.0 +/- 49.7 W; p < 0.01). Patients with CHF showed a higher VE/VCO2 level at peak exercise than normal subjects (CHF, 47.0 +/- 10.7; normal subjects, 35.6 +/- 5.2; p < 0.01). NO concentration of exhaled air at rest was lower in CHF patients than in normal subjects (4.0 +/- 2.2 ppb vs 10.5 +/- 6.2 ppb, respectively; p < 0.05). NO output from the respiratory tract (VNO) was significantly lower in patients with CHF compared with normal subjects at rest (45.3 +/- 24.3 nl/min, 117.5 +/- 60.1 nl/min, respectively, p < 0.05), and although it increased during exercise, it did not increase in patients with CHF as much as in normal subjects (75.3 +/- 43.4 nl/min vs 512.9 +/- 253.6 nl/min, respectively; p < 0.01). The increase above rest (exercise/rest) was smaller in patients with CHF than in normal subjects (2.10 +/- 1.92 vs 4.81 +/- 2.67, p < 0.05). These data support the concept that the smaller increase in NO production (VNO) during exercise may be responsible for a blunted vasodilation in patients with CHF, resulting in a smaller reduction in dead space/tidal volume and VE/VCO2 at the lactic acidosis threshold than normal. This finding may play a role in the abnormally high ventilatory response to exercise in patients with CHF.

Adult↗
PubMed2001

Basal production of pentane in expired gas from healthy humans.

BACKGROUND: Pentane in exhaled gas is often used as an index of lipoperoxidation, but today, there is no standardization for its measurement. In this study, with our technical experience, we determined basal production of pentane in healthy subjects, and we evaluated variability of pentane flow 1 month later. METHODS: 18 subjects inhaled hydrocarbon-free air (HCFA) in order to realize a lung washout. Ambient air and three samples (at T0, T10, T30 min) of expired gas were concentrated using a "trap-and-purge" procedure. For the analysis of pentane, an Al(2)O(3)/KCl plot column contained in a gas chromatograph equipped with a flame ionization detector was used. RESULTS: After 10 min of washout, mean (+/-SD) exhalation rate of pentane was 1+/-0.6 pmol min(-1) kg(-1). After 30 min of washout, mean (+/-SD) exhalation rate of pentane was 0.7+/-0.5 pmol min(-1) kg(-1). No significant difference in pentane flow was shown 1 month later for eight subjects who repeated the protocol. CONCLUSION: With our results and data of the literature, exhalation rates of pentane from healthy adults appear to range between 0.3 and 2 pmol min(-1) kg(-1). The variability of pentane flow 1 month later seems not very important.

Adult↗