Alveolar carbon monoxide: A comparison of methods of measurement and a study of the effect of change in body posture

1988 ◽  
Vol 74 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Andrew J. T. Kirkham ◽  
Andrew R. Guyatt ◽  
Gordon Cumming
Keyword(s):  
Carbon Monoxide ◽  
Linear Models ◽  
Body Posture ◽  
Breath Hold ◽  
Erect Posture ◽  
Indirect Measures ◽  
The Mean ◽  
The Difference ◽  
End Tidal ◽  
Inspired Oxygen

1. We have compared rebreathing, breath-hold and mean alveolar methods of measuring alveolar carbon monoxide (CO), at levels similar to those found in smokers, as a preliminary to using them as indirect measures of carboxyhaemoglobin levels. In the present study alveolar CO levels were raised by rebreathing a 2% CO mixture. 2. Breath-hold CO was measured after breath-hold times of 0–35 s in 5 s increments. Using generalized linear models, the maximum value for breath-hold CO was estimated to occur at 23 s. Breath-hold CO after a 20 and 25 s breath-hold were similar to and significantly greater than those of less than 20 s or greater than 25 s. 3. As expired CO increased, the difference between breath-hold and mean alveolar CO became proportionally larger. On average, breath-hold CO was 24% larger than mean alveolar CO. 4. Rebreathing, breath-hold and mean alveolar CO were compared at four different inspired oxygen concentrations. Expired CO increased significantly with increasing oxygen for all three methods. At end-tidal oxygen levels of less than 25%, breath-hold and rebreathing CO were similar, however, the overall mean difference between the three methods was significant. 5. While rebreathing CO was unaffected by changes in ventilation/perfusion of the lung, induced by change in body posture, both breath-hold and mean alveolar CO showed a significant fall with change from the supine to erect posture. 6. We conclude that under normoxic conditions, rebreathing and breath-hold CO (20 or 25 s breath-hold) were similar, whereas the mean alveolar method produced significantly lower values, presumably due to lack of equilibration. Altering ventilation/perfusion of the lung caused no mean change in the measurement of rebreathing CO but did affect the other methods.

Study on Association between Height, Weight, Iodine Supplementation and Thyroid Volume

2021 ◽  
pp. 1-25
Author(s):  
Lanchun Liu ◽  
Lixiang Liu ◽  
Ming Li ◽  
Yang Du ◽  
Peng Liu ◽  
...  
Keyword(s):  
Iodine Deficiency ◽  
Linear Models ◽  
Thyroid Volume ◽  
Salt Iodization ◽  
Iodine Supplementation ◽  
Random Pairing ◽  
Level Data ◽  
The Mean ◽  
Salt Iodine ◽  
The Difference

Abstract The policy of Universal Salt Iodization (USI) could reduce population’s thyroid volume (TVOL) in iodine deficiency areas. Conversely, the improved growth and developmental status of children might increase the TVOL accordingly. Whether the decreased TVOL by USI conceals the increase effect of height and weight on TVOL is unclear. The aim of this study was to analyse the association between height, weight, iodine supplementation and TVOL. Five national Iodine Deficiency Disorder surveys were matched into four pairs according to the purpose of analysis. County-level data of both detected by paired surveys were incorporated, 1: 1 random pairing method was used to match counties or individuals. The difference of TVOL between different height, weight, different iodine supplementation measures groups and the association between TVOL and them were studied. The mean height and weight of children aged 8-10 years increased from 129.9cm and 26.9kg in 2002 to 136.2cm and 32.1kg in 2019; while the median TVOL decreased from 3.10ml to 2.61ml. Iodine supplementation measures can affect TVOL; after exclude iodine effects, the median TVOL was increased with the height and weight. On the other side, after excluding the influence of height and weight, the median TVOL remained decreased. Only age, weight and salt iodine were significant associated with TVOL in multiple linear models. Development of height and weight in children is the evidence of improved nutrition. The decreased TVOL caused by iodized salt measures conceals the increase effect of height and weight on TVOL. Age, weight, and salt iodine affect TVOL significantly.

scholarly journals Efficacy of providing free nicotine replacement chewing gum to induce quit attempts in tobacco users- A prospective observational study

2021 ◽  
Vol 7 (4) ◽  
pp. 265-270
Author(s):  
Rohini Sharma ◽  
Umashankar G K ◽  
Shuhaib Rahman ◽  
Somanath Patil
Keyword(s):  
Carbon Monoxide ◽  
Observational Study ◽  
Quantitative Detection ◽  
Chewing Gum ◽  
Nicotine Replacement ◽  
Safety Issues ◽  
Quit Attempt ◽  
Quit Attempts ◽  
The Mean ◽  
The Difference

To assess the effectiveness of providing free NRT to tobacco users in increasing quit attempts and to assess the perception of adherence, side effects and safety issues related to the usage in increasing quit attempt. A observational study was conducted to motivate tobacco users to have a quit attempt with a nicotine replacement sample among patients visiting out-patient department of a dental college. Baseline evaluation (demographic), Modified Fagerstrom test for Nicotine Dependence (MFTND) to assess nicotine addiction level, “breath analyzer” for the quantitative detection of levels of carbon monoxide were assessed. A free NRT sample was given. Telephonic follow up was done at an interval of 2 weeks, 1 month to assess the reduction in the mean MFTND score and to assess the perception of using NRT sample. All data was entered and analysed in SPSS for Windows version 22. Among the 40 subjects 80% were in the age group of 30-50 years and were males. The levels of carbon monoxide using breath analyser showed 80% of the subjects as heavy and chain smokers. Out of 40 subjects, 29 (72.5%) subjects were having high dependence calculated using MFTND which reduced to 2(5%) after using nicotine chewing gum. The mean and standard deviation of pre MFTND was 7.97±2.35 and for post MFTND it was 5.57±2.14 and the difference was highly significant (p< 0.005).: The results of this study confirm the efficacy of providing free nicotine replacement sample a novel strategy in motivating tobacco users to induce quit attempt.

scholarly journals Effect of Immediately-After-Birth Weaning on the Development of Goat Kids Born to Small Ruminant Lentivirus-Positive Dams

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 822 ◽  
Author(s):  
Nalbert ◽  
Czopowicz ◽  
Szaluś-Jordanow ◽  
Moroz ◽  
Mickiewicz ◽  
...  
Keyword(s):  
Body Weight ◽  
Sexual Maturity ◽  
Linear Models ◽  
Small Ruminant ◽  
Negative Impact ◽  
Body Weight Gain ◽  
Mixed Linear Models ◽  
Daily Body Weight ◽  
The Mean ◽  
The Difference

A longitudinal study was carried out to investigate the influence of two different rearing systems of young kids on their development to sexual maturity. Kids born to small ruminant lentiviruses-infected (SRLV) female goats were split into two groups: the immediately-after-birth weaned group and the unweaned group. Kids’ body weight (BWT) was measured before the first consumption of colostrum, and then at the age of one week, and one, two, four, and seven months. The relationship between the rearing system and BWT at each age was investigated using mixed linear models adjusted for potential confounders. The mean BWT of kids of the immediately-after-birth weaned group was significantly lower at the age of one week, one month, and two months, and then the difference became insignificant. The mean daily body weight gain (DWG) was significantly lower in the immediately-after-birth weaned group during the whole first month of life, but then DWG in both groups became equal. Crude mortality rate did not differ significantly between groups. This study shows that weaning kids immediately after birth does not appear to have any negative impact on kids’ development except transient growth retardation, which is fully compensated until they reach sexual maturity.

Is alveolar carbon monoxide an unreliable index of carboxyhaemoglobin changes during smoking in man?

1988 ◽  
Vol 74 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Andrew R. Guyatt ◽  
Andrew J. T. Kirkham ◽  
Derek C. Mariner ◽  
Gordon Cumming
Keyword(s):  
Carbon Monoxide ◽  
Breath Holding ◽  
Gas Mixture ◽  
Transient Change ◽  
Holding Period ◽  
Before And After ◽  
The Subject ◽  
The Mean ◽  
The Difference ◽  
Co Gas

1. We measured alveolar carbon monoxide (CO) after a 20 s breath-holding period and carboxyhaemoglobin both before and after smoking a cigarette on 500 occasions (101 individuals). The two measurements were closely correlated but there was a marked difference in the change or ‘boost’ after smoking one cigarette. The mean relative boosts ([post value—pre value]/[pre + post]/2) for alveolar CO and carboxyhaemoglobin were 7.7% and 20.3%, while negative boosts (fall rather than the expected rise) were seen in 103 of 500 and three of 500 occasions respectively. In 140 studies a third alveolar CO reading taken 5 min later was slightly larger, but the difference was insignificant. 2. In seven subjects where the carboxyhaemoglobin level was raised by breathing a 2% CO gas mixture, the alveolar CO and carboxyhaemglobin boosts were similar (71.7% and 75.2% respectively), and they fell sharply subsequently rather than increasing further as occurred after smoking. 3. We conclude that alveolar CO measurements give a useful estimate of carboxyhaemoglobin level if the subject has not smoked for at least half an hour but that measurements of alveolar CO boost are useless since the act of smoking interferes with alveolar sampling. We postulate that cigarette smoking induces a transient change in pulmonary gas exchange.

scholarly journals Time to adapt in the pandemic era: A prospective randomized non–inferiority  study comparing time to intubate  with and without  the barrier box

2020 ◽  
Author(s):  
Praneeth Madabhushi ◽  
Sudhakar Kinthala ◽  
Abistanand Ankam ◽  
Nitin Chopra ◽  
Burdett Porter
Keyword(s):  
Management Practices ◽  
Controlled Trial ◽  
Peripheral Nerve Stimulator ◽  
Secondary Endpoints ◽  
The Mean ◽  
The Difference ◽  
Clinically Significant ◽  
Induction Times ◽  
End Tidal ◽  
Bag Mask Ventilation

Abstract Background The challenges posed by the spread of COVID-19 disease through aerosols have compelled anesthesiologists to modify their airway management practices. Devices such as barrier boxes are being considered as potential adjuncts to full PPE's to limit the aerosol spread. Usage of the barrier box raises concerns of delay in time to intubate (TTI). We designed our study to determine if using a barrier box with glidescope delays TTI within acceptable parameters to make relevant clinical conclusions.Methods 78 patients were enrolled in this prospective non inferiority controlled trial and were randomly allocated to group C (without the barrier box) or the study group BB (using barrier box). The primary measured endpoint is time to intubate (TTI), which is defined as time taken from loss of twitches confirmed with a peripheral nerve stimulator to confirmation of end-tidal CO 2. 15 seconds was used as non-inferiority margin for the purpose of the study .We used an unpaired two-sample single-sided t-test to test our non- inferiority hypothesis (H 0 : Mean TTI diff ≥ 15 seconds, H A : Mean TTI diff < 15 seconds). Secondary endpoints include the number of attempts at intubation, lowest oxygen saturation during induction, and the need for bag-mask ventilation.Results Mean TTI in group C was 42 (CI 19.2 to 64.8) seconds vs. 52.1 (CI 26.1 to 78) seconds in group BB. The difference in mean TTI was 10.1 seconds (CI -∞ to 14.9). We rejected the null hypothesis and concluded with 95% confidence that the difference of the mean TTI between the groups is less than < 15 seconds (95% CI -∞ to 14.9,p = 0.0461). Our induction times were comparable (67.7 vs. 65.9 seconds).100% of our patients were intubated on the first attempt in both groups. None of our patients needed rescue breaths.Conclusions We conclude that in patients with normal airway exam, scheduled for elective surgeries, our barrier box did not cause any clinically significant delay in TTI when airway manipulation is performed by well-trained providers.The study was retrospectively registered at clinicaltrials.gov (NCT04411056) on May 27, 2020

scholarly journals Elevated End-Tidal Carbon Monoxide Concentration in Children with Sickle Cell Anemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1390-1390
Author(s):  
Ashutosh Lal ◽  
Kristen Yen ◽  
Lasandra Patterson ◽  
Alisa Goldrich ◽  
Anne M Marsh ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Young Children ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Second Hand Smoke ◽  
Control Group ◽  
Exhaled Breath ◽  
Healthy Children ◽  
The Mean ◽  
End Tidal

Abstract Background: Carbon monoxide (CO) produced during oxygen-dependent cleavage of porphyrin ring of heme is excreted in exhaled breath. The catabolism of heme is increased when red blood cells are destroyed at an accelerated rate. Thus, quantifying CO in exhaled breath could serve as an indicator of hemolysis. However, the requirement for forced breath sample has limited the measurement of exhaled CO in young children. Objective: To assess end-tidal CO concentration (ETCOc) in children with sickle cell anemia (SCA). Design/Methods: ETCOc was measured using the CoSense ETCO Monitor (Capnia Inc. Palo Alto, CA). Children between 5-14 years with SCA (Hb SS) who were not on chronic transfusions were eligible. Healthy children served as age-matched controls. Children with exposure to second-hand smoke, acute respiratory infection or symptomatic asthma were excluded. End-tidal breath samples were collected by placing the tip of a nasal cannula 5 mm into the nares. Up to 3 measurements were taken for each subject and the highest ETCOc value was used for analysis. (ClinicalTrials.gov: NCT01848691) Results: The mean (range) age of 16 children with SCA and 16 controls was 9.7 years (5-14 years) and 9.9 years (5-14 years), respectively. The mean (± s.d.) ETCOc for SCA was 4.85 ± 2.24 ppm versus 0.96 ± 0.54 ppm for control group (p<0.001). The ETCOc in the control group ranged from 0.2 to 2.3 ppm, but was ≤1.2 ppm in 14/16, which is suggested as the upper limit of normal for healthy children. In the SCA group, the ETCOc range was 1.8 to 9.7 ppm, with values ≥2.4 ppm in 15/16 subjects. A threshold ETCOc value of >2.1 ppm provided both sensitivity and specificity equal to 93.8% (69.8-99.8%) for distinguishing SCA from healthy children. Children with SCA who had higher absolute reticulocyte count also demonstrated higher ETCOc (r=0.62, p=0.011). Patients with severe anemia (hemoglobin <8 g/dL) had a higher mean ETCOc (5.43 ppm) than the rest (4.40 ppm) but the difference was not significant. ETCOc level tended to increase with age in SCA (r=0.45, p=0.08). Conclusions: Carbon monoxide in exhaled breath can be measured in young children in the clinic using a portable monitor. ETCOc may be a valuable tool for non-invasive monitoring of the severity of hemolysis in SCA. The mean ETCOc was 5-fold higher in SCA compared with controls, with little overlap seen between the groups. This suggests a potential use for ETCOc as a point-of-care screening test for SCA in children. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures Lal: Capnia, Inc: Research Funding. Yen:Capnia, Inc. : Employment. Bhatnagar:Capnia, Inc: Employment.

Deep inspiration breath hold (DIBH) with electromagnetic surface transponder confirmation of chest wall (CW) position during radiation for left breast cancer.

2014 ◽  
Vol 32 (26_suppl) ◽  
pp. 126-126
Author(s):  
Madeera Kathpal ◽  
Kelly Sun ◽  
Cynthia Malmer ◽  
Stephanie Ninneman ◽  
Stacie Wendt ◽  
...  
Keyword(s):  
Free Breathing ◽  
Left Breast ◽  
Breath Hold ◽  
Breast Cancers ◽  
Deep Inspiration Breath Hold ◽  
Heart Dose ◽  
Real Time Tracking ◽  
The Mean ◽  
The Difference ◽  
Ischemic Events

126 Background: DIBH during radiation of left breast cancers reduces heart dose, potentially reducing late cardiac ischemic events, but requires a treatment CW position significantly different from a free-breathing (FB) position. We sought to improve the accuracy of radiation therapy during DIBH by using electromagnetic surface transponders to track the position of the CW during treatment. We examined the benefit of this technique in reducing dose to the heart and consistently reproducing the DIBH position. We also evaluated the difference between FB and DIBH CW position and compared CW movement within the plateau of each DIBH to within beam-on time. Methods: 15 patients participated in this IRB-approved study. Patients were planned and treated using DIBH. We fused treatment-position FB CT scans to DIBH scans to compare mean heart (MH) and left anterior descending coronary artery (LAD) dose. We used surface transponder tracking reports to determine CW motion at the time of daily port films, during FB, the plateau of each DIBH, and beam-on time. We summed anterior and superior motion using the Pythagorean Theorem and report our results in this combined axis. Paired t-test was used to compare heart dose with vs. without DIBH and CW motion during plateau DIBH vs. beam-on. Results: DIBH significantly reduced MH and LAD dose vs. FB plans (MH 1.26 ± 0.51 Gy v 2.84 ± 1.55 Gy, p < 0.01), (LAD 5.49 ± 4.02 Gy v 18.15 ± 8.78 Gy, p < 0.01). DIBH CW position was a mean of 13.9 ± 5.3 mm anterior and superior to FB position. The mean difference in CW position at the time of daily port film vs. beam-on was -1.0 ± 2.5 mm. Plateau DIBH CW motion was 2.8 ± 2.3 mm, significantly increased from CW motion during beam-on (1.1 ± 1.2 mm, p < 0.01). Treatment was paused in 23% of fractions to adjust for suboptimal breath hold or CW position. Conclusions: DIBH reduced the MH and LAD dose by at least 50%. Real-time tracking with electromagnetic transponders allowed us to limit treatment to the most stable portion of the DIBH plateau, significantly reducing intra-fraction motion. Electromagnetic confirmation of CW position allowed verification of breath-hold reproducibility.

scholarly journals Prediction Model for Cigarette Yields Derived from Data Obtained under Two Different Machine Smoking Regimes

2015 ◽  
Vol 26 (7) ◽  
Author(s):  
Stéphane Colard
Keyword(s):  
Carbon Monoxide ◽  
Prediction Model ◽  
Smoking Intensity ◽  
Burning Process ◽  
Testing Scheme ◽  
The Mean ◽  
The Difference ◽  
Burning Model ◽  
Ignition Propensity

Summary“Tar”, nicotine and carbon monoxide (TNCO) cigarette yields determined under different smoking regimes, with and without ventilation blocking, are linearly related to the difference Δt between the smouldering time (cigarette combustion with no puffing) and the smoking time (cigarette combustion with puffing). Δt forms then the basis of yield predictions. The smoulder rate determination used in the calculation of Δt can be difficult for low ignition propensity cigarettes which present some tendency for selfextinguishment. This issue was overcome in a novel testing scheme involving the determination of number of puffs and smoking times under two different smoking regimes and inputting this data into a cigarette burning model. This enabled us to characterise the burning process and provided an extensive set of information such as the mean smoulder rate between puffs or the mass of tobacco burnt during puffs regardless of the smoking regime applied.Good correlations were observed between the mass of tobacco burnt during puffs and TNCO or B[a]P yields. Correlations provide a way to link yields from one smoking regime to another and confirm that yields determined from one regime are sufficient to establish the relationships between yields and smoking intensity. It was concluded that smoke yields for arbitrary smoking regimes can potentially be predicted by determining the puff numbers and smoking times from two different smoking regimes and the smoke yields from only one regime. This testing scheme allows a comprehensive characterisation of a cigarette at reduced cost. [Beitr. Tabakforsch. Int. 26 (2015) 320-333]

Establishing a gradient between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide in patients with acute respiratory distress syndrome

2016 ◽  
Vol 65 (2) ◽  
pp. 338-341 ◽  
Author(s):  
Tariq Yousuf ◽  
Taylor Brinton ◽  
Ghulam Murtaza ◽  
Daniel Wozniczka ◽  
Khansa Ahmad ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Statistical Significance ◽  
End Tidal Carbon Dioxide ◽  
The Mean ◽  
The Difference ◽  
End Tidal

End-tidal carbon dioxide (ETCO2) monitoring is useful in many situations. However, ETCO2 monitoring is unreliable in patients with acute respiratory distress syndrome (ARDS) due to widespread lung inflammation. In our study, we attempt to establish the gradient between the arterial pressure of carbon dioxide (PaCO2) and ETCO2 in patients with ARDS, which we defined as the PaETCO2 gradient. The main objective of the study was to establish a PaETCO2 gradient in each severity of ARDS. We analyzed 35 patients with ARDS and a total of 88 arterial blood gases were included. PaCO2, PaO2/FiO2 and ETCO2 were measured. Patients were stratified into mild, moderate and severe ARDS as classified by the Berlin ARDS criteria. PaCO2 and ETCO2 were compared at each severity stratification. The mean PaCO2 was 50.0, the mean ETCO2 was 26.6 and the gradient among all samples was 23.24 (±12.02). The mean gradient for each severity is as follows: mild: 19.3 (±9.9), moderate: 27.9 (±13.2) and severe: 23.9 (±7.8). The difference between the PaETCO2 gradient of the mild to moderate (p=0.001) and mild to severe groups (p=0.01) reached statistical significance. However, the difference between the moderate to severe groups did not reach statistical significance (p=0.48). We found the gradient between PaCO2 and ETCO2 in patients with ARDS is vast and tends to worsen with increasing severity of ARDS. This indicates that the gradient between the 2 may be used as an indicator of increasing severity of ARDS.

Respiratory dead space and arterial to end-tidal CO2 tension difference in anesthetized man

1960 ◽  
Vol 15 (3) ◽  
pp. 383-389 ◽  
Author(s):  
J. F. Nunn ◽  
D. W. Hill
Keyword(s):  
Tidal Volume ◽  
Dead Space ◽  
Artificial Respiration ◽  
Physiological Dead Space ◽  
Anatomical Dead Space ◽  
The Subject ◽  
The Mean ◽  
The Difference ◽  
End Tidal ◽  
End Tidal Co2

Observations were made during both spontaneous and artificial respiration on 12 fit patients anesthetized for routine surgical procedures. Above a tidal volume of 350 ml (BTPS), the anatomical dead space was close to the predicted normal value for the subject. Below 350 ml, it was reduced in proportion to the tidal volume. The physiological dead space (below the carina) approximated to 0.3 times the tidal volume for tidal volumes between 163 and 652 ml (BTPS). Throughout the range the physiological dead space was considerably in excess of the anatomical dead space measured simultaneously. The difference (alveolar dead space) varied from 15 to 231 ml, being roughly proportional to the tidal volume. The mean arterial to end-tidal CO2 tension difference was 4.6 (S.D. ±2.5) mm Hg and not related to tidal volume or arterial CO2 tension. None of the findings appeared to depend on whether the respiration was spontaneous or artificial. Submitted on September 25, 1959

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