Increase In Carboxyhemoglobin Research Articles

Chronic household air pollution and exposure patterns among Himalayan nomads.

Household air pollution (HAP) is a major risk factor of non-communicable diseases, causing millions of premature deaths each year in developing nations. Populations living at high altitudes are particularly vulnerable to HAP and associated health outcomes. This study aims to explore the relationships between activity patterns, HAP, and an HAP biomarker among 100 Himalayan nomadic households during both cooking and heating-only periods. Household CO was monitored in 100 rural homes in Qinghai, China, at 3500 m on the Himalayan Plateau among Himalayan nomads. Carboxyhemoglobin (COHb) was used as a biomarker to assess exposure among 100 male and 100 female heads of household. Linear mixed-effects models were used to explore the relationship between COHb and activity patterns. Cooking periods were associated with 7 times higher household CO concentrations compared with heating periods (94 ± 56 ppm and 13 ± 11 ppm, respectively). Over the three-day biomarker-monitoring period in each house, 99% of subjects had at least one COHb measurement exceeding the WHO safety level of 2%. Cooking was associated with a 32% increase in COHb (p < 0.001). This study on household air pollution (HAP) in high-altitude regions provides important insights into the exposure patterns of nomadic households in Qinghai, China. The study found that cooking is the primary factor influencing acute carbon monoxide (CO) exposure among women, while heating alone is sufficient to elevate CO exposure above WHO guidelines. The results suggest that cooking-only interventions have the potential to reduce HAP exposure among women, but solutions for both cooking and heating may be required to reduce COHb to below WHO guidelines. This study's findings may inform future interventions for fuel and stove selection to reduce HAP and exposure among other populations.

Study on the Mechanism of the Pink Tooth Phenomenon Using Bovine Teeth: A Pilot Study.

The pink teeth phenomenon has occasionally been observed in forensic autopsies. This study aimed to establish an experimental pink tooth model and an objective color tone evaluation method in order to clarify changes in the color tone of teeth and the relationship with hemoglobin monoxide and its decomposition products and with red pigment-producing bacteria, under various external environmental factors. It was confirmed that the color tone evaluation with ΔE and the L*C*h color space was useful. The results of various examinations using this model showed that color development was suppressed under aerobic conditions, faded early under light, became bright red under a low temperature and showed a tendency to be reddish at 3 days under high humidity and in the presence of soft tissue. The biochemical analysis revealed a significant increase in carboxyhemoglobin at 7 days and a tendency toward increasing the total heme pigment and bilirubin levels over time. The bacteriological analysis revealed that red pigment-producing bacteria increased over time but that the color faded after 7 days. These results suggest that putrefaction greatly affects the pink teeth phenomenon, whereas red pigment-producing bacteria have little effect on the occurrence of pink teeth. However, further studies are needed to clarify bacteriological involvement.

Working Period and CO Exposure Relationship with Changes Levels COHb of Bus Station Officer

Carbon monoxide inhaled into the lungs will enter the blood circulation and inhibit the entry of oxygen needed by the body. This gas combines with hemoglobin to form carboxyhemoglobin (COHb). The increase in COHb in the blood will inhibit the function of oxygen transportation and will affect the health of workers. This study aims to determine the risk factors for increasing COHb in Tirtonadi Bus Station Surakarta officers. The research method used analytic observational with a cross-sectional design. The research population was 110 respondents with a purposive sampling technique to get a research sample of 43 respondents. CO levels in the environment were measured by a CO meter, while COHb levels were measured by a spectrophotometer. The research data were analyzed using Spearman rank. Statistical correlation test showed a significant relationship between CO levels in the environment and COHb levels, p-value = 0.000 and r-value = 0.897, and no significant relationship between length of work and COHb levels with p-value = 0.285 and r-value = - 0.167. CO in the environment is related to the COHb level of traffic security officers at Tirtonadi Bus Station Surakarta, and the length of work is not related to the COHb level of traffic security officers at Tirtonadi Bus Station Surakarta.

Pulse Oximetry Is Unreliable in Patients on Veno-Venous Extracorporeal Membrane Oxygenation Caused by Unrecognized Carboxyhemoglobinemia.

Continuous bedside pulse oximetry (SpO2) is universally used to monitor oxygenation for patients supported on veno-venous extracorporeal membrane oxygenation (VV-ECMO). Yet, elevated carboxyhemoglobin (COHb), a known event in VV-ECMO, diminishes the reliability of SpO2. This retrospective cohort study aims to assess the accuracy of SpO2 compared with oxyhemoglobin (SaO2) and quantify COHb levels by co-oximetry in the VV-ECMO population. Forty patients on VV_ECMO from 2012 to 2017 underwent 1,119 simultaneous SaO2 and SpO2 measurements. Most patients were male (60%) with average age of 46 years. SpO2 overestimated SaO2 values by 2.35% at time of cannulation and 0.0061% for each additional hour on VV-ECMO (p < 0.0001). Twenty-nine (72.5%) patients developed elevated COHb (>3% of hemoglobin saturation) at least once during VV-ECMO support and 602 (40.2%) arterial blood gases yielded elevated COHb levels. Mean duration for ECMO with elevated COHb was 244 hours compared with 98 hours in patients without (p < 0.0048). Patients who developed COHb were younger (mean age 40 vs. 55 years, p < 0.024) and had single-site double-lumen cannulation (odds ratio = 4.5, p = 0.23). At time of cannulation, mean COHb was 2.18% and increased by 0.0054% for each additional hour (p < 0.0001). For every 1% increase in COHb, SaO2 decreased by 1.1% (p < 0.0001). During VV-ECMO, SpO2 often overestimates SaO2 by substantial margins. This is attributable to rising COHb levels proportional to duration on VV-ECMO. In this population where adequate oxygen delivery is often marginal, clinicians should be wary of the reliability of continuous pulse oximetry to assess oxygenation.

Urgentno zbrinjavanje trovanja ugljen monoksidom kod radnika naftne industrije

Introduction/Aim Carbon monoxide (CO) is a gas produced by incomplete combustion of carbon compounds and is a leading cause of poising throughout the world. The objective of this paper is to analyze 5 cases of acute carbon monoxide poisoning in petroleum industry workers, occupying a shared accommodation and to present diagnostic, therapeutic and preventive measures. Case report the workers had to be treated by the emergency medical service during the night for health problems arising from carbon monoxide inhalation from a faulty installation. Venous blood samples were collected to measure the concentration of carboxyhemoglobin (COHb) and gas analyses were done upon admission and 120 minutes later. They were treated with parenteral therapy and oxygen by mask, and they made a complete recovery. Conclusion Faulty installation of a gas-powered heating system caused acute carbon monoxide poisoning in 5 people occupying the space. After 120 minutes in a closed environment, the carbon monoxide concentration was high enough to cause a significant increase of COHb in the venous blood. Prompt diagnosis and adequate therapy are crucial to ensure a favorable treatment outcome. Preventive measures, such as educating workers and introducing health and safety measures into the work environment are extremely important in preventing accidents such as these.

Trends and characteristics of cases when serial carboxyhemoglobins are obtained

Carboxyhemoglobin (COHb) levels are obtained when there is suspicion for carbon monoxide (CO) exposure. Serial COHb levels are sometimes obtained despite the well-established half-life of COHb with oxygen supplementation. We sought to evaluate the trends and characteristics associated with obtaining serial carboxyhemoglobin levels. A retrospective review was performed at an academic medical center for all inpatient and emergency department cases with either single COHb or serial COHb levels from 1 April 2010 through 31 March 2015. Data collected included age, gender, pregnancy status, smoking history, encounter month, admission status, oxygen administration, fire or burn history, vital signs, presenting symptoms, hyperbaric oxygen (HBO2) therapy use, initial pH, troponin, lactate, and COHb levels. The time and change in values between serial levels were also obtained. 624 cases were identified, with 106 (17%) having multiple carboxyhemoglobin levels. A mean of 2.6 (range 2 - 9) serial COHb levels were obtained. The average initial COHb was 8.9%. Subsequent serial levels were obtained on average at 353, 663 and 1,095 minutes and averaged 2.8%, 1.8% and 1.1% respectively. Serial COHb levels were obtained more commonly in burn patients, those admitted to the ICU and those who had HBO2 therapy. Four patients had an increase in COHb level on serial testing. The largest increase of these was from 2.0% to 3.9%. Serial COHb levels were not infrequent in this study. No clinically significant increase in COHb was identified by serial testing. Further studies should examine the clinical utility of such practices.

The Effect of a 30-Min Water-Pipe Smoking Session on Cognitive Measures and Cardio-Pulmonary Parameters.

One session of water-pipe tobacco smoking (WPS) can increase carboxyhemoglobin (COHb) to levels comparable to those reported in carbon monoxide poisoning, which may cause memory impairment and confusion. A prospective study evaluating healthy volunteers pre- and post-30 min of WPS session. Primary outcome parameters were executive cognitive measures [digit span test and Paced Auditory Serial Addition Test (PASAT)]. The effect of repeated cognitive testing 30 min apart without WPS was evaluated in age- and sex-matched healthy volunteers. Secondary outcome parameters included cardio-pulmonary, COHb, serum nicotine, and cytokine changes. Thirty-five subjects aged 25.6 ± 4.5 years smoked water-pipe for a 30-min session. Control group included 20 subjects aged 25.2 ± 5.1 years. Digit span test median score decreased after WPS (16 and 15, respectively, p = .003), insignificant decrease in controls. Median PASAT score increased after WPS (49 and 52, respectively, p = .009); however, a much larger significant increase was observed in controls (p ≤ .001). One WPS session resulted in significant increases in heart and respiratory rates and significant decrease in FEF25-75%. Post WPS, median COHb levels increased (from 2.2% to 10.7%, p < .0001) as did median serum nicotine levels (from 1.2 to 26.8 ng/mL, p < .0001). Serum cytokines levels: IL-2 and IL-6 increased (p < .0001 for each), and IL-10 and IL-5 decreased (p < .0001 and p = .04, respectively). One session of WPS resulted in significant negative effects on cognitive executive measures, significant increases in COHb and serum nicotine levels, and significant changes in serum cytokines. Our findings call for increasing awareness towards the possible consequences of cognitive alterations following a 30-min session of WPS. One 30-min session of water-pipe smoking resulted in negative effects on executive cognitive measures, increased carboxyhemoglobin and serum nicotine, and significant changes in serum cytokine levels. This study adds to the accumulating evidence on the harmful effects of water-pipe smoking, a growing epidemic, and calls for awareness of its possible consequences of acute cognitive alterations.

Carbon Monoxide Exposure in Youth Ice Hockey.

To examine the effect of ice resurfacer type on carboxyhemoglobin levels in youth hockey players. We hypothesized that players in arenas with electric resurfacers would have normal, stable carboxyhemoglobin levels during games, whereas those in arenas with internal combustion engine (IC) resurfacers would have an increase in carboxyhemoglobin levels. Prospective cohort study. Enclosed ice arenas in the northeastern United States. Convenience sample of players aged 8 to 18 years old in 16 games at different arenas. Eight arenas (37 players) used an IC ice resurfacer and 8 arenas (36 players) an electric resurfacer. Carboxyhemoglobin levels (SpCO) were measured using a pulse CO-oximeter before and after the game. Arena air was tested for carbon monoxide (CO) using a metered gas detector. Players completed symptom questionnaires. The change in SpCO from pregame to postgame was compared between players at arenas with electric versus IC resurfacers. Carbon monoxide was present at 6 of 8 arenas using IC resurfacers, levels ranged from 4 to 42 parts per million. Carbon monoxide was not found at arenas with electric resurfacers. Players at arenas with IC resurfacers had higher median pregame SpCO levels compared with those at electric arenas (4.3% vs 1%, P < 0.01). Players in the IC group also had a significant increase in their SpCO level during a hockey game compared with those in the electric group (2.8% vs 1%, P = 0.01). There were no significant differences in symptom scores. Players at arenas operating IC resurfacers had significantly higher SpCO levels. Youth hockey players in arenas with IC resurfacers have an increase in carboxyhemoglobin during games and have elevated baseline carboxyhemoglobin levels compared with players at arenas with electric resurfacers. Electric resurfacers decrease the risk of CO exposure.

Évolution de la carboxyhémoglobinémie et de la méthémoglobinémie lors de résections endoscopiques : une étude observationnelle

Combustion of organic tissues due to endoscopic resection could induce methemoglobin (MetHb) and carboxyhemoglobin (COHb) formation. The aim of this study is to evaluate MetHb and COHb formation in patients undergoing prostatic or bladder endoscopic procedures. COHb and MetHb measurements were performed in 44patients at the beginning and end of the procedure. A third measurement was done in patients who stayed more than one hour in the recovery room. Means were compared using Student t-test, simple regressions were used for quantitative variables and ANOVA for categorical variables. Multiple linear regressions were used for multivariate analysis. COHb increased by 0.5±0.9% (95% CI: 0.2to 0.7% P=0.001). MetHb increase was 0.0±0.4% (95% CI: -0.1to 0.2% P=0.552). In univariate analysis, the variables associated with COHb increase are the length of surgery, the amount of irrigation fluid and location (prostate or bladder) of the procedure. In the multivariate model, COHb increase is associated with the amount of liquid and the location. MetHb did not increase during endoscopic surgery. In contrast, COHb increases, and can, in some patients, exceed 2-4%. This could be responsible for a decreased angina threshold in patients with ischemic heart disease. 4.

Hemodynamic Implications of Carbon Monoxide (CO) and Nitrogen Oxide (NO) during Living Donor Liver Transplantation.

Carbon monoxide (CO) and nitrogen oxide (NO) affect vasodilation and cause hemodynamic change. Hemodynamic instability due to liver transplantation may result in poor prognosis of graft. This study investigated the hemodynamic implications of CO and NO levels measured using carboxyhemoglobin (COHb) and methemoglobin (MetHb) during living donor liver transplantation (LDLT). The hemodynamic instability with a pressor dose (norepinephrine equivalent) was estimated 1 hour after graft reperfusion. COHb and MetHb were used as indexes of CO and NO, and were measured using an arterial blood gas analyzer. One hundred and ten recipients who underwent LDLT from May 2011 to July 2013 were selected. Recipients were divided into high (≥ 1.9%) and low (< 1.9%) COHb groups with COHb concentrations at 5 minutes after reperfusion. Recipients were also divided into high (≥ 0.4%) and low (< 0.4%) MetHb groups with MetHb concentrations at 30 minutes after reperfusion. Data are presented as mean ± standard deviation or number (percentage). Model for End-stage Liver Disease (MELD) scores were different for the two COHb groups (low: 13.4 ± 9.0 vs. high: 19.7 ± 10.6, p < 0.001), and pressor doses adjusted by MELD scores were also different between the two COHb groups (low: 0.09 ± 0.01 μg/kg/min vs. high: 0.14 ± 0.01 μg/kg/min, p = 0.029). By contrast, pressor doses and MELD scores were not different between the two MetHb groups. In conclusion, CO rather than NO has hemodynamic implications during LDLT. Therefore, the increase in COHb during LDLT is predictive of hemodynamic instability.

Carboxyhaemoglobin formation and ECG changes during hysteroscopic surgery, transurethral prostatectomy and tonsillectomy using bipolar diathermy.

Diathermy is known to produce a mixture of waste products including carbon monoxide. During transcervical hysteroscopic surgery, carbon monoxide might enter the circulation leading to the formation of carboxyhaemoglobin. In 20 patients scheduled for transcervical hysteroscopic resection of myoma or endometrium, carboxyhaemoglobin was measured before and at the end of the surgical procedure, and compared with levels measured in 20 patients during transurethral prostatectomy, and in 20 patients during tonsillectomy. Haemodynamic data, including ST-segment changes, were recorded. Levels of carboxyhaemoglobin increased significantly during hysteroscopic surgery from median (IQR [range]) 1.0% (0.7-1.4 [0.5-4.9])% to 3.5% (2.0-6.1 [1.3-10.3]%, p<0.001), compared with levels during prostatectomy or tonsillectomy. Significant ST-segment changes were observed in 50% of the patients during hysteroscopic surgery. Significant correlations were observed between the increase in carboxyhaemoglobin and the maximum ST-segment change (ρ = -0.707, p<0.01), between the increase in carboxyhaemoglobin and intravasation (ρ = 0.625; p<0.01), and between intravasation and the maximum ST-segment change (ρ = -0.761; p<0.01). The increased carboxyhaemoglobin levels during hysteroscopic surgery appear to be related to the amount of intravasation and this could potentially be a contributing factor to the observed ST-segment changes.

Laboratory and Clinical Acute Effects of Active and Passive Indoor Group Water-Pipe (Narghile) Smoking

Indoor group water-pipe tobacco smoking, commonly referred to as water-pipe smoking (WPS), especially in coffee shops, has gained worldwide popularity. We performed a comprehensive laboratory and clinical evaluation of the acute effects of active and passive indoor group WPS. This comparative study evaluated pre- and post-30-min active and passive indoor group WPS. The outcome parameters were carboxyhemoglobin (COHb), nicotine, and cotinine levels; CBC count; and cardiorespiratory parameters. Exhaled breath condensate (EBC) cytokines and endothelial function (using the EndoPat device [Itamar Medical Ltd]) were measured only in active smokers. Statistical methods used were Student t test, Wilcoxon signed rank test, Fisher exact test, analysis of variance, and Newman-Keuls post hoc test where relevant. Sixty-two volunteers aged 24.9±6.2 years were included; 47 were active smokers, and 15 were passive smokers. COHb level increased postactive WPS (active smokers, 2.0%±2.9% vs 17.6%±8.8%; P<.00001); six subjects (12.7%) had a >25% increase, and two subjects (4.2%) had a >40% increase. Plasma nicotine level increased postactive WPS (active smokers, 1.2±4.3 ng/mL vs 18.8±13.9 ng/mL; P<.0001); plasma cotinine and urinary nicotine and cotinine levels also increased significantly. EBC IL-4, IL-5, IL-10, IL-17, and γ-interferon decreased significantly with postactive smoking; endothelial function did not change. WPS was associated with adverse cardiorespiratory changes. In passive smokers, COHb level increased (0.8%±0.25% vs 1.2%±0.8%, respectively, P=.003) as did respiratory rate. One session of active indoor group WPS resulted in significant increases in COHb and serum nicotine levels (eightfold and 18-fold, respectively) and was associated with adverse cardiorespiratory health effects. The minor effects found in passive smokers suggest that they too may be affected adversely by exposure to WPS. The results call for action to limit the continuing global spread of WPS in coffee shops. ClinicalTrials.gov; No.: NCT1237548; URL: www.clinicaltrials.gov.

The effect of induction of endogenous CO by heme-oxygenase inducer, hemin versus heme-oxygenase blocker, zinc mesoporphyrin on gastric secretion and ulceration under different conditions in adult male albino rats.

Although its role and importance is less well studied, carbon monoxide (CO) has been identified as the second gasotransmitter in the GI tract. This study was performed to investigate the effect of modifying the endogenous CO production by altering heme oxygenase (HO) activity either by induction through hemin administration or inhibition by zinc mesoporphyrin administration on gastric secretion and ulceration induced by either cold restraint stress (CRS) or indomethacin (IND) treatment in adult male albino rats. Our results revealed that hemin significantly increased HO-1 levels with an increase in carboxyhemoglobin (COHb) level while zinc mesoporphyrin significantly decreased HO-1 levels with a decrease in COHb level in all groups. Hemin pretreatment significantly attenuated the gastric mucosal lesions induced by CRS and IND administration, which was accompanied by significant reduction in free and total acidity of gastric secretion, decreased proteolytic activity and marked attenuation of lipid peroxidation inspite of decreased NO and PGE2 levels. On the other hand, Inhibition of HO-1 activity by zinc mesoporphyrin prevented most of the effects caused by hemin administration except for its similar reduction in gastric mucosal NO and PGE2 levels. On conclusion, Hemin exerts a protective effect against CRS and IND-induced gastric ulcers possibly via inducing HO-1 and increasing endogenous production of CO (Tab. 2, Fig. 4, Ref. 75).

Acute Effects of Passive Smoking on Endothelial Function

Impairment of endothelial functions has been shown to occur after acute and chronic exposure to passive smoking (PS), as assessed by flow-mediated dilatation (FMD) of the brachial artery. A total of 61 participants, 30 male and 31 female, mean ages 26 (18-36) were enrolled in the study. All were clinically well and nonsmokers. All participants stayed for 30 minutes in the smoking room. Carbon monoxide (CO) level was 7.42 ± 0.98 ppm (4.71-10.50). Mean carboxyhemoglobin (COHb) levels of participants were significantly elevated after PS. Mean FMD was 18.6% ± 9% and decreased to 12.4% ± 7% after PS (P < .001). In the current study, with more number of participants at lower CO concentrations (7.42 ppm) and with smaller increase in COHb (51%) significant reduction (33%, P < .001) in FMD was observed.

Simulations of exercise and brain effects of acute exposure to carbon monoxide in normal and vascular-diseased persons

At some level, carboxyhemoglobin (COHb) due to inhalation of carbon monoxide (CO) reduces maximum exercise duration in both normal and ischemic heart patients. At high COHb levels in normal subjects, brain function is also affected and behavioral performance is impaired.These are findings from published experiments that are, due to ethical or practical considerations, incomplete in that higher or lower ranges of COHb, and exercise have not been well studied. To fill in this knowledge base, a whole-body human physiological model was used to make estimates of physiological functioning by the simulation of parametric exposures to CO and various exercise levels. Ischemic heart disease was simulated by introducing a stenosis in the left heart arterial supply. Brain blood flow was also limited by such a stenosis. To lend credibility to such estimation, the model was tested by simulating experiments from the published literature. Simulations permitted several new conclusions. Increases in COHb produced the largest decreases in exercise duration when exercise was least strenuous and when COHb was smallest. For ischemic heart disease subjects, the greatest change in exercise duration produced by COHb increase was when ischemia and COHb was smallest. Brain aerobic metabolism was unaffected until COHb exceeded 25%, unless the maximum brain blood supply was limited by a stenosis greater than 50% of normal. For higher levels of stenosis, aerobic brain metabolism was reduced for any increase in COHb level, implying that behavior would be impaired with no “threshold” for COHb.

Exogenous carbon monoxide does not affect cell membrane energy availability assessed by sarcolemmal calcium fluxes during myocardial ischaemia–reperfusion in the pig

Carbon monoxide is thought to be cytoprotective and may hold therapeutic promise for mitigating ischaemic injury. The purpose of this study was to test low-dose carbon monoxide for protective effects in a porcine model of acute myocardial ischaemia and reperfusion. In acute open-thorax experiments in anaesthetised pigs, pretreatment with low-dose carbon monoxide (5% increase in carboxyhaemoglobin) was conducted for 120 min before localised ischaemia (45 min) and reperfusion (60 min) was performed using a coronary snare. Metabolic and injury markers were collected by microdialysis sampling in the ventricular wall. Recovery of radio-marked calcium delivered locally by microperfusate was measured to assess carbon monoxide treatment effects during ischaemia/reperfusion on the intracellular calcium pool. Coronary occlusion and ischaemia/reperfusion were analysed for 16 animals (eight in each group). Changes in glucose, lactate and pyruvate from the ischaemic area were observed during ischaemia and reperfusion interventions, though there was no difference between carbon monoxide-treated and control groups during ischaemia or reperfusion. Similar results were observed for glycerol and microdialysate ⁴⁵Ca(2+) recovery. These findings show that a relatively low and clinically relevant dose of carbon monoxide did not seem to provide acute protection as indicated by metabolic, energy-related and injury markers in a porcine myocardial ischaemia/reperfusion experimental model. We conclude that protective effects of carbon monoxide related to ischaemia/reperfusion either require higher doses of carbon monoxide or occur later after reperfusion than the immediate time frame studied here. More study is needed to characterise the mechanism and time frame of carbon monoxide-related cytoprotection.

The Effects of Acute Passive Smoke Exposure on Endothelium-Dependent Brachial Artery Dilation in Healthy Individuals

Passive smoking has both short-term and long-term vascular effects. It is not clear whether impairment of endothelial function reflects the acute effects of passive smoke exposure or the chronic effects. The purpose of this study was to assess the hypothesis that short-term exposure to passive smoke impairs endothelium-dependent vasodilation in healthy nonsmokers. Eighteen healthy young never smokers (12 men, 6 women) 21 to 55 years old (mean +/- SD: 34 +/-9 years) underwent ultrasonography measuring baseline brachial-artery diameter and brachial-artery diameter during hyperemia and after sublingual administration of nitroglycerin, twice: in a smoke-free environment, and then in the same environment polluted by 30 to 35 ppm carbon monoxide. Each subject served as his/her control. Carboxyhemoglobin was measured in blood samples of subjects tested. Mean value of carboxyhemoglobin was 0.6 +/-0.5% in a smoke-free environment and 1.4 +/- 0.5% in a smoking environment (p <0.02). Mean values of flow-mediated dilation (FMD) were 12.6% +/- 7.8% in a smoke-free environment versus 6.8 +/- 7.8% in a smoking environment (p <0.01). On the contrary, nitroglycerin-induced vasodilation did not show any statistical difference (21 +/- 9.8% versus 23 +/-1.4%). Finally, the increase of carboxyhemoglobin was related statistically to the impairment of flow-mediated dilation (r = 0.51; p <0.002). Passive smoking impaired flow-mediated vasodilation in healthy never smokers in a smoking environment. The impairment was strongly related to carboxyhemoglobin level.

Inhaled carbon monoxide inhibits intimal hyperplasia and provides added benefit with nitric oxide

Carbon monoxide (CO) and nitric oxide (NO) have both been shown to possess vasoprotective properties. NO has successfully inhibited intimal hyperplasia in both small-animal and large-animal experimental models, whereas CO has only been studied in rodents. Evidence suggests that these two molecules may exert their vascular effects through common as well as unique signaling pathways. The purpose of this study was to determine the effect of a low concentration of inhaled CO on intimal hyperplasia in a large-animal model and if CO and NO treatment could exert a synergistic effect to inhibit this process. Balloon angioplasty was performed in a porcine model. Animals received inhaled CO (250 ppm) delivered preoperatively for 60 minutes or preoperatively and intraoperatively. Blood was collected for carboxyhemoglobin (COHgb) measurements at the start of the operation and every 30 minutes during the operation. Heart rate, respiratory rate, and oxygen saturation were monitored throughout. To study the effect of combined CO and NO treatment, another group of pigs received inducible NO synthase (iNOS) gene transfer in one iliac artery and control gene transfer (AdlacZ) in the contralateral iliac artery, with or without preoperative and intraoperative inhaled CO. Adenoviral infection was performed immediately after balloon injury. All animals were euthanized at 3 weeks, and iliac arteries were collected for histologic and morphometric analysis. One hour of pretreatment with CO was associated with modest and transient elevations in COHgb levels, resulting in a 25.6% reduction in neointimal area and a 10% reduction in intimal area/medial area ratio (I/M) 3 weeks after injury (NS). In contrast, preoperative followed by intraoperative CO administration increased COHgb in a sustained fashion and inhibited neointima formation by 51.7% and I/M by 31% (P < .001). There was no evidence of toxicity associated with this administration of CO. The treatment of injured iliac arteries with the control adenoviral vector AdlacZ did not further increase the inhibitory effect of CO on intimal hyperplasia. The combination of inhaled CO and iNOS gene transfer resulted in greater protection, however, with a 64% reduction in neointimal area and a 48% reduction in I/M (P < .001). CO is an effective means of reducing intimal hyperplasia in large animals after vascular injury when delivered during the operative procedure. No toxicity was associated with the increase in COHgb. The combination of CO and NO provided additional protection against the vascular injury response, with a greater reduction in neointima formation. These data suggest that these agents may prove to be clinically beneficial in prolonging vascular patency after interventions.

Prenatal cigarette smoke exposure: Pregnancy outcome and gestational changes in plasma nicotine concentration, hematocrit, and carboxyhemoglobin in a newly standardized rat model

Epidemiological studies support an association between perinatal cigarette smoke (CS) exposure and a number of severe pre- and postnatal complications. However, the mechanisms through which CS enhances such risks largely remain unknown. One of the reasons for our inability to discover such mechanisms has been the unavailability of a clinically relevant and physiologically concordant animal model. A number of studies have previously used nicotine (Nic) as surrogate for CS. We sought to (1) establish the amount of CS exposure to achieve plasma Nic concentrations observed among moderate to heavy smokers (20-60 ng/ml), (2) investigate the temporal changes in plasma Nic concentrations, carboxyhemoglobin, and hematocrit with advancing pregnancy, and (3) elucidate the effects of CS exposure on pregnancy outcome. Pregnant Sprague-Dawley rats were exposed to various doses of CS or room air (Sham) from days 6 to 21 of gestation. Exposure to 6000 ml/day of CS led to very high plasma Nic concentrations and increased maternal and fetal mortality (P < 0.001). The plasma Nic concentrations remained higher than those observed in moderate smokers until the CS dose was reduced to 1000 ml/day and showed dose-dependent temporal changes with advancing gestational age. Significant increases in carboxyhemoglobin and hematocrit were observed in the CS group as compared with the Sham group (P < 0.001). In addition, prenatally CS exposed fetuses had lower birth weight as compared with the Sham group (P = 0.04). Our current study establishes a newly standardized and physiologically relevant model to investigate the mechanisms of CS-mediated adverse effects during the critical period of fetal development.

Acute Respiratory Diseases and Carboxyhemoglobin Status in School Children of Quito, Ecuador

Outdoor carbon monoxide comes mainly from vehicular emissions, and high concentrations occur in areas with heavy traffic congestion. CO binds to hemoglobin, forming carboxyhemoglobin (COHb), and reduces oxygen delivery. We investigated the link between the adverse effects of CO on the respiratory system using COHb as a marker for chronic CO exposure. We examined the relationship between acute respiratory infections (ARIs) and COHb concentrations in school-age children living in urban and suburban areas of Quito, Ecuador. We selected three schools located in areas with different traffic intensities and enrolled 960 children. To adjust for potential confounders we conducted a detailed survey. In a random subsample of 295 children, we determined that average COHb concentrations were significantly higher in children attending schools in areas with high and moderate traffic, compared with the low-traffic area. The percentage of children with COHb concentrations above the safe level of 2.5% were 1, 43, and 92% in low-, moderate-, and high-traffic areas, respectively. Children with COHb above the safe level are 3.25 [95% confidence interval (CI), 1.65–6.38] times more likely to have ARI than children with COHb < 2.5%. Furthermore, with each percent increase in COHb above the safety level, children are 1.15 (95% CI, 1.03–1.28) times more likely to have an additional case of ARI. Our findings provide strong evidence of the relation between CO exposure and susceptibility to respiratory infections.