Clamping end-tidal carbon dioxide during graded exercise with control of inspired oxygen

2016 ◽  
Vol 231 ◽  
pp. 28-36 ◽  
Author(s):  
Saro D. Farra ◽  
Cathie Kessler ◽  
James Duffin ◽  
Greg D. Wells ◽  
Ira Jacobs
2006 ◽  
Vol 104 (5) ◽  
pp. 944-949 ◽  
Author(s):  
Edith Fleischmann ◽  
Friedrich Herbst ◽  
André Kugener ◽  
Barbara Kabon ◽  
Monika Niedermayr ◽  
...  

Background Supplemental perioperative oxygen increases tissue oxygen tension and decreases incidence of wound infection in colorectal surgery patients. Mild intraoperative hypercapnia also increases subcutaneous tissue oxygen tension. However, the effect of hypercapnia in patients already receiving supplemental oxygen is unknown, as is the effect of mild hypercapnia on intestinal oxygenation in humans-although the intestines are presumably the tissue of interest for colon surgeries. The authors tested the hypothesis that mild intraoperative hypercapnia increases both subcutaneous tissue and intramural intestinal oxygen tension in patients given supplemental oxygen. Methods Patients undergoing elective colon resection were randomly assigned to normocapnia (n = 15, end-tidal carbon dioxide tension 35 mmHg) or mild hypercapnia (n = 15, end-tidal carbon dioxide tension 50 mmHg). Intraoperative inspired oxygen concentration was 80%. The authors measured subcutaneous tissue oxygen tension in the right upper arm and intramural oxygen tension in the left colon. Measurements were averaged over time within each patient and, subsequently, among patients. Data were compared with chi-square, unpaired t, or Mann-Whitney rank sum tests; P < 0.05 was significant. Results Morphometric characteristics and other possible confounding factors were similar in the groups. Intraoperative tissue oxygen tension in hypercapnic patients was significantly greater in the arm (mean +/- SD: 116 +/- 29 mmHg vs. 84 +/- 25 mmHg; P = 0.006) and colon (median [interquartile range]: 107 [81-129] vs. 53 [41-104] mmHg; P = 0.020). Conclusions During supplemental oxygen administration, mild intraoperative hypercapnia increased tissue oxygen tension in the arm and colon. Previous work suggests that improved tissue oxygenation will reduce infection risk via the proposed pathomechanism, although only an outcome study can confirm this.


2006 ◽  
Vol 105 (6) ◽  
pp. 1081-1086 ◽  
Author(s):  
Frederick W. Cheney ◽  
Karen L. Posner ◽  
Lorri A. Lee ◽  
Robert A. Caplan ◽  
Karen B. Domino

Background The authors used the American Society of Anesthesiologists Closed Claims Project database to determine changes in the proportion of claims for death or permanent brain damage over a 26-yr period and to identify factors associated with the observed changes. Methods The Closed Claims Project is a structured evaluation of adverse outcomes from 6,894 closed anesthesia malpractice claims. Trends in the proportion of claims for death or permanent brain damage between 1975 and 2000 were analyzed. Results Claims for death or brain damage decreased between 1975 and 2000 (odds ratio, 0.95 per year; 95% confidence interval, 0.94-0.96; P < 0.01). The overall downward trend did not seem to be affected by the use of pulse oximetry and end-tidal carbon dioxide monitoring, which began in 1986. The use of these monitors increased from 6% in 1985 to 70% in 1989, and thereafter varied from 63% to 83% through the year 2000. During 1986-2000, respiratory damaging events decreased while cardiovascular damaging events increased, so that by 1992, respiratory and cardiovascular damaging events occurred in approximately the same proportion (28%), a trend that continued through 2000. Conclusion The significant decrease in the proportion of claims for death or permanent brain damage from 1975 through 2000 seems to be unrelated to a marked increase in the proportion of claims where pulse oximetry and end-tidal carbon dioxide monitoring were used. After the introduction and use of these monitors, there was a significant reduction in the proportion of respiratory and an increase in the proportion of cardiovascular damaging events responsible for death or permanent brain damage.


2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
J Ferreira ◽  
P Rio ◽  
A Castelo ◽  
I Cardoso ◽  
S Silva ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: None. Background Although several cardiopulmonary exercise testing (CPET) parameters have already proved to predict prognosis, there is increasing interest in finding variables that do not require maximal effort. End-tidal carbon dioxide pressure (PETCO2), an indirect indicator of cardiac output, is one of such variables. Studies in heart failure populations already suggest its role as a prognostic factor. However, data concerning other populations are still scarce. Purpose To assess the association between exercise PETCO2, cardiac biomarkers and systolic function following acute myocardial infarction (AMI) and to evaluate its potential prognostic role in this population. Methods A retrospective single-centre analysis was conducted including patients who underwent symptom-limited CPET early after AMI. We assessed PETCO2 at baseline (PETCO2-B), at anaerobic threshold (PETCO2-AT) and at peak exercise and calculated the difference between PETCO2-AT and PETCO2-B (PETCO2-difference). We analysed their association with B-natriuretic peptide (BNP), maximal troponin after AMI as well as with left ventricular ejection fraction (LVEF) 1 year after. Results We included 40 patients with a mean age of 56 years (87.5% male), assessed with CPET a median of 3 months after AMI (80% of which were ST-elevation myocardial infarctions). Average respiratory exchange ratio was 1,1 with 48% of patients not reaching maximal effort. Mean PETCO2-AT was 37mmHg, with a mean increase from baseline of 6mmHg (PETCO2-difference). There was a significant positive correlation between all the PETCO2 variables measured and BNP values at time of AMI and on follow-up (best correlation for PETCO2-AT with BNP at AMI hospitalization, r = 0.608, p < 0.001). Maximal troponin was not correlated with PETCO2. Both PETCO2-AT and PETCO2-difference were significantly and positively correlated with LVEF 1-year post-AMI (r = 0.421, p = 0.040 and r = 0.511, p = 0.011, respectively). Conclusion PETCO2-AT and PETCO2-difference are both correlated with BNP, an established prognostic marker, and with medium-term systolic function after AMI, suggesting their potential prognostic role in this population. Further studies with larger samples are required to confirm the results of this pilot study and assess PETCO2 as a definite predictor of prognosis after AMI.


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