Open air carbon monoxide poisoning

The J = 1-0 to 4-3 spectral lines of SD+3 were measured in the 152-610 GHz region using a source-modulated microwave spectrometer. The SD+3 ion was generated in a free space absorption cell by a hollow-cathode discharge in a gas mixture of D2S and D2. The rotational constant B0 and the centrifugal distortion constants DJ and DJK were determined from the measured frequencies. A vibration-rotation analysis was carried out and the rz structures of SH+3 and SD+3 were derived from their zero point averaged rotational constants, expressed as SH+3: rz = 1.36512(22) ? and thetaz = 94.098(26) degrees, and SD+3: rz = 1.36086(16) ? and thetaz = 94.1211(195) degrees, where the difference between thetaz(HSH) and thetaz(DSD) was assumed to be the same as that between thetaz(HPH) of PH3 and thetaz(DPD) of PD3. From the shift between the rz structures of SH+3 and SD+3, the re structure of SH+3 was estimated to be re = 1.35001(113) ?, thetae = 94.181(135) degrees. Copyright 1998 Academic Press.     

A randomized, controlled trial of adding expired carbon monoxide feedback to brief stop smoking advice: Evaluation of cognitive and behavioral effects.

Objective: To determine the effect of adding biomarker feedback (expired air carbon monoxide) to standard quit advice on cognitive antecedents of behavior change and smoking cessation and to identify potential effect moderators and mediators. Design: Smokers (N = 160) were randomized to a control (quit advice plus leaflet) or an intervention condition (as control group plus carbon-monoxide level feedback). Cognitive measures were assessed immediately after the intervention and behavioral measures at 6 months' follow-up. Main Outcome Measures: Primary outcome measures were threat and efficacy appraisal, fear arousal, and intention to stop smoking. Secondary outcome measures were quit attempts within the last 6 months and 7-day point prevalence abstinence. Results: Threat appraisal was significantly enhanced in the intervention compared with the control group, t(158) = 2.29, p = .023, as was intention to stop smoking in the next month, t(151) = 2.9, p = .004. However, this effect on intention to stop smoking was short-lived. Groups did not differ in terms of quit attempts or abstinence at follow-up, but the intervention increased the likelihood of cessation in smokers with higher self-efficacy, χ2(1) = 5.82, p = .016. Conclusions: Carbon-monoxide level feedback enhances the effect of brief quit advice on cognitive antecedents of behavior change and smoking cessation rates but further research is required to confirm the longevity of this effect and its applicability to smokers with low self-efficacy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Isoprene from expired air inside a private car

In a rat model of postoperative ileus, induced by abdominal surgery, we investigated the effect of mu- and kappa-opioid receptors. Different degrees of inhibition of the gastrointestinal transit, measured by the migration of Evans blue, were achieved by skin incision, laparotomy or laparotomy plus manipulation of the gut. Morphine (1 mg/kg), a preferential mu-opioid receptor agonist, significantly inhibited the transit after skin incision, while the transit after the laparotomy with or without manipulation was not significantly affected. Fedotozine (5 mg/kg), a peripheral kappa-opioid receptor agonist, enhanced the transit after laparotomy plus manipulation, while naloxone (1 mg/kg), a non-specific opioid receptor antagonist, further inhibited the transit after laparotomy plus manipulation. Naloxone and fedotozine alone had no effect on the transit after skin incision or laparotomy without manipulation. However, naloxone prevented the effect of morphine on the transit after skin incision and of fedotozine on the laparotomy plus manipulation. These results support a role for peripheral kappa-opioid receptors in the pathogenesis of postoperative ileus induced by abdominal surgery.     

Chronic carbon monoxide poisoning: from smoking to accidental poisoning

The authors describe a case of furosemide possibly inhibiting the hypoprothrombinemic effect of warfarin. The initiation of furosemide dosing in a patient receiving a stable dose of warfarin was associated with an 28% decrease in the international normalized ration (INR). Using normal volunteers, two previous controlled studies of an interaction between warfarin and chlorthalidone, and between warfarin and spironolactone, assert that volume depletion produced by forced diuresis results in the inhibition of warfarin's hypoprothrombinemia. Consistent with this hypothesis, the authors found that their patient's hematocrit (believed to reflect hydration status) correlated with the INR: r2 = 0.78, p < 0.05. This case provides further evidence suggesting that acute diuresis can decrease the hypoprothrombinemic effect of warfarin.     

Usefulness of CO measurement in expired air in the study of tobacco consumption by youths and adolescents]

The objective of our work was to know the relationship between carbon monoxide (CO) levels in expired air and smoking habits among school youths and the relationships that can be established between CO level and some peculiar attitudes regarding consume by youths, such as the number of cigarettes, inhaling technique and time elapsed since the last cigarette was smoked. The study, of cross-sectional design, was performed in two high school centres and a total of 777 students who answered a questionnaire and had an expired air CO sample in their own schoolroom tested were enrolled. CO determination in the schoolroom was a simple and attainable technique for the pupils, as only 32 cases (4.1%) had to be excluded due to poor collaboration or poor technique. The mean (mean and SD) CO level in the control group (n = 247), made up by non-smokers nor tobacco tasters was 4.75 (2.46) ppm, statistically lower than among smokers (p < 0.001), but with no differences compared with non smokers (n = 563), who had a CO level of 5.23 (3.4) ppm. This figure was also lower (p < 0.001) than that obtained in the smokers (12.6 [6.3] ppm), made up of 214 pupils, with a mean consume of 2.7 (1.69) cigarettes/day. Among smokers the mean abstinence time since the last cigarette was smoked was 26 (44) minutes and 54% of them admitted to have smoked in the last 10 minutes. CO in expired air correlated significantly with the number of smoked cigarettes (r = 0.58; p < 0.001). Likewise, it correlated significantly with abstinence minutes (r = -0.38; p < 0.001). The time required for CO level to decrease below 10 ppm was 140 minutes in four cases and 120 minutes in 33 cases.     

Relationship of Type A behavior pattern in smokers to carbon monoxide exposure and smoking topography.

Compared exposure to cigarette smoke in 42 graduate and undergraduate student smokers assessed for the Type A behavior pattern. After controlling for smoking rate and cigarette carbon monoxide yield, Type As' alveolar carbon monoxide (COa) levels were higher than Type Bs', and Jenkins Activity Survey scores were correlated with COa. To determine the source of this difference, smoking topography was measured in 10 Type As and 10 Type Bs. Results suggest that consummatory behaviors of Type As may help account for the Type A–coronary heart disease relationship for smokers. Due to increased smoke exposure, Type A smokers may also be at greater risk for cancer and lung disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection and estimation of azomethane in expired air of 1,2-dimethylhydrazine-treated rats

Azomethane (AM) gas was identified as a major metabolite of 1,2-dimethylhydrazine (1,2-DMH) in the expired air of F344 rats. The compound was characterized by high-pressure liquid chromatography, gas chromatography, and mass spectrometry, in comparison to a synthetic standard. At a dose of 21 mg 1,2-DMH/kg sc, approximately 14 and 11% of the dose were exhaled as AM and CO2, respectively, in 24 hours. At 200 mg 1,2-DMH/kg, 23 and 4% of the dose appeared as AM and CO2, respectively, in the respired air within the same period. Most AM was seen in the first 6 hours, but the CO2 evolution was more progressive, especially after the higher dose of 1,2-DMH.     

Nitric oxide in expired air from rats with experimental bronchitis

Bronchitis was evoked in 20 rats by SO2 inhalation. Ten rats were exposed to SO2 only, 10 others were exposed to SO2 and treated with heparin simultaneously. The control group consisted of other 10 rats. NO concentration in the air exhaled by all animals was determined. The experiment was carried out in a specially constructed chamber. It lasted 15 weeks. In the group of animals exposed to SO2 only, NO concentration was found beginning from the %th week, with the maximum concentration in the 10th week. In the group of animals exposed to SO2 and treated with heparin NO concentration was much lower than in the above group. NO was not found in the control group. The conclusion is that NO concentration in the exhaled air is a result of bronchial inflammation, and can be decreased during treatment with heparin.     

Screening for carbon monoxide in children

We present the use of risperidone as a potentiation strategy of the serotonergic antidepressants in four patients suffering from refractory obsessive-compulsive disorder. There were an important improvement in three patients. Adding risperidone to serotonergic antidepressants causes complex interactions between serotonergic, dopaminergic and noradrenergic systems, that could lay to the clinical improvement. These and other similar cases make necessary controlled studies. Adding risperidone to serotonergic antidepressants in patients suffering from refractory obsessive-compulsive disorder might be an effective strategy with low risk for secondary effects and without the presence of tics or psychotic symptoms.     

Detection of isoprene in expired air from human subjects using proton-transfer-reaction mass spectrometry

A new analytical method using proton-transfer-reaction mass spectrometry (PTRMS) is described for the determination of trace constituents in human breath. PTRMS is sufficiently sensitive and specific that it does not require preconcentration or separation. At its present stage of development it is capable of detecting trace constituents present in air at the part-per-billion level. These capabilities are illustrated for isoprene, one of the most abundant endogenous hydrocarbons. Our results confirm recent observations of a diurnal level variation associated with sleep or wakefulness; a new finding is that young children have much lower levels of isoprene in breath than adults. To address the metabolic origin of human isoprene, we used PTRMS to analyze expired air for allylic C5 alcohols that have been proposed to be non-enzymatic precursors of isoprene. The lack of correlation between peak breath isoprene and these alcohols suggests that the hydrocarbon is formed by some other mechanism.     

Endogenous carbon monoxide in control of respiration

CASE REPORT: A patient with recurrent breast cancer was reirradiated twice on adjacent fields with a time interval of 9 months. The first time she was treated with reirradiation alone, the second time with reirradiation plus hyperthermia. The reirradiation schedule for both fields was 8 x 4 Gy in 4 weeks. Both fields overlapped partly with the field of postoperative radiotherapy, which was applied 57 and 66 months earlier to a total dose of 40.5 Gy. RESULTS: During the 52 to 61 months follow-up, a remarkable difference in telangiectasia development, between the parts of the reirradiation fields overlapping with the primary radiotherapy field, became apparent. Telangiectasia was observed 9 months after treatment with reirradiation alone and progressed to confluent in 47 months after treatment. In the reirradiation plus hyperthermia area, the maximum observed telangiectasia was slight until 52 months after treatment. DISCUSSION: The difference in the development of telangiectasia between these fields cannot be explained by differences in any of the known radiation treatment related prognostic factors. A protective effect by hyperthermia has been suggested by Haveman and coworkers, who have shown experimentally that heat treatment leads to enhanced proliferation of endothelial cells, thereby inducing a fast repopulation and replacement of X-ray damaged cells. CONCLUSION: This difference in telangiectasia formation is an interesting observation. Whether such a protective effect of hyperthermia is of general relevance has to become clear from more extensive clinical studies.     

Estimation of blood gas contents from expired air under normal and pathologic conditions

Methods of estimating arterial-venous O2 content difference, mixed venous CO2 content and tension, and average arterial CO2 content are presented. They are based on the continuous gas analysis of expired air during a prolonged expiration. The influence of CO2 storage in lung tissue and certain pathophysiologic conditions on the accuracy of these methods was systematically investigated with a comprehensive multi-chamber computer simulation of the lung. For normal levels of CO2 storage capacity, satisfactory estimates of arterial-venous O2 content difference are feasible for differences less than 8 volumes percent; with high levels of CO2 storage capacity, large errors can occur. Storage of CO2 in lung tissue causes large errors in the estimates of mixed venous CO2 content and tension, and average arterial CO2 content; reliable estimates do not appear to be feasible from analysis of expired gas. Simulated pathophysiologic conditions of interstitial pulmonary edema or atelectasis also introduce large errors. This analysis delineates the theoretic limitations of an estimation technique in clinical applications where acute respiratory dysfunctions occur.     

Successful treatment of habitual smokers with warm, smoky air and rapid smoking.

Presented either warm smoky air or warm mentholated air to 28 undergraduate habituated smokers and required them to smoke until they could tolerate no further cigarettes. Both groups smoked at a rapid rate, received considerable social reinforcement, and were given comparable expectation of success. All Ss were abstinent at termination after an average of 8 sessions, and 16 of 25 Ss followed up for 6 mo. remained abstinent. The warm smoky air and menthol air groups did not differ, but paradoxically, Ss followed up at 4-wk intervals were more successful than Ss contacted every 2 wk. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oxytocin release is inhibited by the generation of carbon monoxide from the rat hypothalamus--further evidence for carbon monoxide as a neuromodulator

Recent evidence suggests that the gas nitric oxide can modulate the secretion of a number of hypothalamic hormones, and may be co-localized particularly to oxytocin-containing neurons. Another gas, carbon monoxide (CO), has also been suggested to play a role in neural signaling in the brain, and the synthetic enzyme responsible for the generation of carbon monoxide has been reported to be present in the rat hypothalamus. In this study, we have therefore investigated whether CO has the ability to modify the release of oxytocin from acute rat hypothalamic explants. Hemin, a specific CO precursor through the enzyme heme oxygenase (the enzymatic pathway synthesizing endogenous CO, was found to inhibit KCl-stimulated oxytocin release, with a maximal effect at 10(-5) M, while showing no effect on basal oxytocin secretion. The stimulation of oxytocin by serotonin 10 ng/ml was also significantly antagonized by hemin 10(-7) M. An inhibitor of heme oxygenase, zinc-protoporphyrin-9, had no effect on basal or stimulated oxytocin release. When hemin and zinc-protoporphyrin-9 were given together, the hemin-induced inhibition of oxytocin was completely antagonized by the enzyme inhibitor. Ferrous hemoglobin A0, a substance known to bind CO with high affinity, had no effect on either basal or stimulated oxytocin release, but when hemin and ferrous hemoglobin A0 were given together the hemin-induced inhibition of oxytocin was completely blocked. These findings provide evidence that endogenous CO may play a role in the control of oxytocin release and that, by analogy with nitric oxide, CO may represent a major new neuroendocrine modulator.     

Pulse oximetry in severe carbon monoxide poisoning

STUDY OBJECTIVES: To evaluate the accuracy and quantitate the error of pulse oximetry measurements of arterial oxygenation in patients with severe carbon monoxide (CO) poisoning. DESIGN: Retrospective review of patient clinical records. SETTING: Regional referral center for hyperbaric oxygen therapy. PATIENTS: Thirty patients referred for treatment of acute severe CO poisoning who demonstrated carboxyhemoglobin (COHb) levels >25%, with simultaneous determinations of arterial hemoglobin oxygen saturation by pulse oximetry (SpO2) and arterial blood gas (ABG) techniques. MEASUREMENTS AND RESULTS: COHb levels and measurements of arterial oxygenation from pulse oximetry, ABG analysis, and laboratory CO oximetry were compared. SpO2 did not correlate with COHb levels. SpO2 consistently overestimated the fractional arterial oxygen saturation. The difference between arterial hemoglobin oxygen saturation (SaO2) calculated from ABG analysis and SpO2 increased with increasing COHb level. CONCLUSIONS: Presently available pulse oximeters overestimate arterial oxygenation in patients with severe CO poisoning. An elevated COHb level falsely elevates the SaO2 measurements from pulse oximetry, usually by an amount less than the COHb level, confirming a prior observation in an animal model. Accurate assessment of arterial oxygen content in patients with CO poisoning can currently be performed only by analysis of arterial blood with a laboratory CO-oximetry.