Exploratory analysis of nonlinear coupling between EEG global field power and end-tidal carbon dioxide in free breathing and breath-hold tasks

Author(s):  
Maria Sole Morelli ◽  
Gaetano Valenza ◽  
Alberto Greco ◽  
Alberto Giannoni ◽  
Claudio Passino ◽  
...  
Author(s):  
Maria Sole Morelli ◽  
Nicola Vanello ◽  
Alejandro Luis Callara ◽  
Valentina Hartwig ◽  
Michelangelo Maestri ◽  
...  

While the brainstem is in charge of the automatic control of ventilation, the cortex is involved in the voluntary control of breathing but also receives inputs from the brainstem, which influence the perception of breathing and the arousal state and sleep architecture in conditions of hypoxia/hypercapnia. We evaluated in eleven healthy subjects the effects of breath hold (BH: 30 seconds of apneas and 30 seconds of normal breathing) and BH-related CO2/O2 changes on electroencephalogram (EEG) global field power (GFP) and regional field power (RFP) in 9 different areas (3 rostrocaudal sections -anterior, central, posterior- and 3 sagittal sections -left, middle, right) in the δ and α bands, by cross correlation analysis. No significant differences were observed in GFP and RFP when comparing free breathing (FB) with the BH task. Within the BH task, the shift from apnea to normal ventilation was accompanied by an increase in the δ power and a decrease in the α power. The end-tidal pressure of CO2 (PETCO2) was positively correlated with the δ-band and negatively with the α- band with a positive time shift, while an opposite behaviour was found for the end-tidal pressure of O2 (PETO2). Notably, the time shift between PETCO2/PETO2 signals and cortical activity at RFP was heterogenous and seems to follow a hierarchical activation with the δ-band responding earlier than the α band. Overall, these findings suggest that the effect of BH on the cortex may follow specific ascending pathways from the brainstem and be related to chemoreflex stimulation.


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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