A physiological model for predicting carboxyhemoglobin formation from exposure to carbon monoxide in rats

1999 ◽  
Vol 86 (6) ◽  
pp. 1977-1983 ◽  
Author(s):  
Edgar C. Kimmel ◽  
Robert L. Carpenter ◽  
James E. Reboulet ◽  
Kenneth R. Still
Keyword(s):  
General Model ◽  
Minute Ventilation ◽  
Blood Gas Analysis ◽  
Physiological Model ◽  
Specific Model ◽  
Gas Analysis ◽  
Model Parameters ◽  
Total Blood ◽  
Continuous Simulation ◽  
Model Predictions

A time-dependent simulation model, based on the Coburn-Forster-Kane equation, was written in Advanced Continuous Simulation Language to predict carboxyhemoglobin (HbCO) formation and dissociation in F-344 rats during and after exposure to 500 parts/million CO for 1 h. Blood-gas analysis and CO-oximetry were performed on samples collected during exposure and off-gassing of CO. Volume displacement plethysmography was used to measure minute ventilation (V˙e) during exposure. CO diffusing capacity in the lung (Dl CO) was also measured. Other model parameters measured in the animals included blood pH, total blood volume, and Hb concentration. Comparisons between model predictions using values forV˙e, Dl CO, and the Haldane coefficient cited in the literature and predictions using measured V˙e, Dl CO, and calculated Haldane coefficient for individual animals were made. General model predictions using values for model parameters derived from the literature agreed with published HbCO values by a factor of 0.987 but failed to simulate experimental data. On average, the general model overpredicted measured HbCO level by nearly 9%. A specific model using the means of measured variables predicted HbCO concentration within a factor of 0.993. When experimentally observed parameter fluctuations were included, the specific model predictions reflected experimental effects on HbCO formation.

scholarly journals Inverse problems in reduced order models of cardiovascular haemodynamics: aspects of data assimilation and heart rate variability

2017 ◽  
Vol 14 (126) ◽  
pp. 20160513 ◽  
Author(s):  
Sanjay Pant ◽  
Chiara Corsini ◽  
Catriona Baker ◽  
Tain-Yen Hsia ◽  
Giancarlo Pennati ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Inverse Problems ◽  
Unscented Kalman Filter ◽  
Clinical Situation ◽  
Specific Model ◽  
Patient Specific ◽  
Model Parameters ◽  
Heart Rates ◽  
Model Predictions ◽  
Patient State

Inverse problems in cardiovascular modelling have become increasingly important to assess each patient individually. These problems entail estimation of patient-specific model parameters from uncertain measurements acquired in the clinic. In recent years, the method of data assimilation, especially the unscented Kalman filter, has gained popularity to address computational efficiency and uncertainty consideration in such problems. This work highlights and presents solutions to several challenges of this method pertinent to models of cardiovascular haemodynamics. These include methods to (i) avoid ill-conditioning of the covariance matrix, (ii) handle a variety of measurement types, (iii) include a variety of prior knowledge in the method, and (iv) incorporate measurements acquired at different heart rates, a common situation in the clinic where the patient state differs according to the clinical situation. Results are presented for two patient-specific cases of congenital heart disease. To illustrate and validate data assimilation with measurements at different heart rates, the results are presented on a synthetic dataset and on a patient-specific case with heart valve regurgitation. It is shown that the new method significantly improves the agreement between model predictions and measurements. The developed methods can be readily applied to other pathophysiologies and extended to dynamical systems which exhibit different responses under different sets of known parameters or different sets of inputs (such as forcing/excitation frequencies).

Belastungstest bei chronisch-obstruktiver Lungenerkrankung: Wege zur optimalen Trainingssteuerung finden

2020 ◽  
Vol 8 (6) ◽  
pp. 330-331
Author(s):  
Daniela Leitl ◽  
A. Rembert Koczulla
Keyword(s):  
Minute Ventilation ◽  
Chronic Obstructive Lung Disease ◽  
Blood Gas Analysis ◽  
Cardiopulmonary Exercise Test ◽  
Gas Analysis ◽  
Stage I ◽  
Stage Iii ◽  
Chronic Obstructive ◽  
Gold Stage ◽  
Copd Patients

<b>Background:</b> In moderate-to-severe chronic obstructive pulmonary disease (COPD) patients the 6-min walk test (6MWT) is often exhaustive and correlates with the incremental cycle cardiopulmonary exercise test (CPET). <b>Objectives:</b> The aim of this study was to assess the agreement between oxygen uptake (VO<sub>2</sub>) measured during the 6MWT by portable equipment and incremental cycle exercise in COPD patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) I–IV. <b>Methods:</b> A total of 30 patients with COPD GOLD I–IV (14 patients GOLD stage I and II and 16 patients GOLD stage III and IV) underwent a 6MWT and an incremental CPET. Breath-by-breath analysis for VO<sub>2</sub>, carbon dioxide output (VCO<sub>2</sub>), and minute ventilation (VE) were measured during each test. Blood gas analysis and lactate measurements were performed before, during, and after the test. <b>Results:</b> VO<sub>2</sub> in COPD patients GOLD stage I and II was 16.2 ± 4.2 mL/kg/min measured by 6MWT and 20.5 ± 7.0 mL/kg/min measured by CPET as compared to GOLD stage III and IV (11.2 ± 3.7 mL/kg/min measured by 6MWT and 15.5 ± 4.3 mL/kg/min measured by CPET). No significant correlation in VO<sub>2</sub> measurements could be found between both tests in COPD GOLD I and II (<i>r</i> = 0.17), whereas the VO<sub>2</sub> significantly correlated in patients with COPD stage III and IV (<i>r</i> = 0.7). <b>Conclusions:</b> A significant relationship between VO<sub>2</sub> measured by 6MWT and CPET could only be found in patients with more severe COPD but not in milder stages. 6MWT and CPET provide different VO<sub>2</sub> measurements in COPD patients. The two methods cannot be used interchangeably.

Efficacy of Near-Infrared Spectrometry for Monitoring the Cerebral Effects of Severe Dilutional Anemia

2014 ◽  
Vol 17 (3) ◽  
pp. 154 ◽  
Author(s):  
Arıtürk Cem ◽  
Ustalar Serpil ◽  
Toraman Fevzi ◽  
Ökten Murat ◽  
Güllü Ümit ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Surgery ◽  
Blood Lactate ◽  
Near Infrared ◽  
Bypass Graft ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Infrared Spectrometry ◽  
Control Group ◽  
Near Infrared Spectrometry

<p><strong>Introduction:</strong> Clear guidelines for red cell transfusion during cardiac surgery have not yet been established. The current focus on blood conservation during cardiac surgery has increased the urgency to determine the minimum safe hematocrit for these patients. The aim of this study was to determine whether monitoring of cerebral regional oxygen saturation (rSO<sub>2</sub>) via near-infrared spectrometry (NIRS) is effective for assessing the cerebral effects of severe dilutional anemia during elective coronary arterial bypass graft surgery (CABG).</p><p><strong>Methods:</strong> The prospective observational study involved patients who underwent cerebral rSO<sub>2</sub> monitoring by NIRS during elective isolated first-time CABG: an anemic group (<em>N</em>=15) (minimum Hemoglobin (Hb) N=15) (Hb &gt;8 g/dL during CPB). Mean arterial pressure (MAP), pump blood flow, blood lactate level, pCO<sub>2</sub>, pO<sub>2</sub> at five time points and cross-clamp time, extracorporeal circulation time were recorded for each patient. Group results statistically were compared.</p><p><strong>Results:</strong> The anemic group had significantly lower mean preoperative Hb than the control group (10.3 mg/dL versus 14.2 mg/dL; <em>P</em> = .001). The lowest Hb levels were observed in the hypothermic period of CPB in the anemic group. None of the controls exhibited a &gt;20% decrease in cerebral rSO<sub>2</sub>. Eleven (73.3%) of the anemic patients required an increase in pump blood flow to raise their cerebral rSO<sub>2</sub>.</p><p><strong>Conclusions:</strong> In this study, the changes in cerebral rSO<sub>2</sub> in the patients with low Hb were within acceptable limits, and this was in concordance with the blood lactate levels and blood-gas analysis. It can be suggested that NIRS monitoring of cerebral rSO<sub>2</sub> can assist in decision making related to blood transfusion and dilutional anemia during CPB.</p>

Blood gas analysis in newborns with low cardiac output syndrome after cardiac surgery.

2018 ◽  
Vol 19 (5) ◽  
pp. 676-687
Author(s):  
G.G. Khubulava ◽  
A.B. Naumov ◽  
S.P. Marchenko ◽  
O.Yu. Chupaeva ◽  
A.A. Seliverstova ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Cardiac Surgery ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Blood Gas ◽  
Low Cardiac Output Syndrome ◽  
Low Cardiac Output

Prognostic Value of Oxygenated Hemoglobin Assessed during Acute Exacerbations of Chronic Pulmonary Disease

Respiration ◽  
2021 ◽  
pp. 1-8
Author(s):  
Clemens F. Hinke ◽  
Rudolf A. Jörres ◽  
Peter Alter ◽  
Robert Bals ◽  
Florian Bornitz ◽  
...  
Keyword(s):  
Pulmonary Disease ◽  
Predictive Value ◽  
Hemoglobin Concentration ◽  
Blood Gas Analysis ◽  
Study Data ◽  
Gas Analysis ◽  
Chronic Obstructive ◽  
Acute Exacerbations ◽  
All Cause Mortality

<b><i>Background:</i></b> Oxygenated hemoglobin(OxyHem) is a simple-to-measure marker of oxygen content capable of predicting all-cause mortality in stable chronic obstructive pulmonary disease (COPD). <b><i>Objectives:</i></b> We aimed to analyze its predictive value during acute exacerbations of COPD (AECOPD). <b><i>Methods:</i></b> In this retrospective study, data from 227 patients discharged after severe AECOPD at RoMed Clinical Center Rosenheim, Germany, between January 2012 and March 2018, was analyzed. OxyHem (hemoglobin concentration [Hb] × fractional SpO<sub>2</sub>, g/dL) was calculated from oxygen saturation measured by pulse oximetry and hemoglobin assessed within 24 h after admission. The follow-up (1.7 ± 1.5 years) covered all-cause mortality, including readmissions for severe AECOPD. <b><i>Results:</i></b> During the follow-up period, 127 patients died, 56 due to AECOPD and 71 due to other reasons. Survivors and non-survivors showed differences in age, FVC % predicted, C-reactive protein, hemoglobin, Cr, Charlson Comorbidity Index (CCI), and OxyHem (<i>p</i> &#x3c; 0.05 each). Significant independent predictors of survival were BMI, Cr or CCI, FEV<sub>1</sub> % predicted or FVC % predicted, Hb, or OxyHem. The predictive value of OxyHem (<i>p</i> = 0.006) was superior to that of Hb or SpO<sub>2</sub> and independent of oxygen supply during blood gas analysis. OxyHem was also predictive when using a cutoff value of 12.1 g/dL identified via receiver operating characteristic curves in analyses including either the CCI (hazard ratio 1.85; 95% CI 1.20, 2.84; <i>p</i> = 0.005) or Cr (2.04; 95% CI 1.35, 3.10; <i>p</i> = 0.001) as covariates. <b><i>Conclusion:</i></b> The concentration of OxyHem provides independent, easy-to-assess information on long-term mortality risk in COPD, even if measured during acute exacerbations. It therefore seems worth to be considered for broader clinical use.

scholarly journals The effect of clamped and unclamped umbilical cord samples on blood gas analysis

2021 ◽  
Author(s):  
Elisabetta Colciago ◽  
Simona Fumagalli ◽  
Elena Ciarmoli ◽  
Laura Antolini ◽  
Antonella Nespoli ◽  
...  
Keyword(s):  
Blood Gas Analysis ◽  
Cross Sectional Study ◽  
Gas Analysis ◽  
Blood Collection ◽  
Large Sample Size ◽  
Blood Gas ◽  
Delayed Cord Clamping ◽  
Cross Sectional ◽  
High Risk Women ◽  
Significant Difference

Abstract Purpose Delayed cord clamping for at least 60 s is recommended to improve neonatal outcomes. The aim of this study is to evaluate whether there are differences in cord BGA between samples collected after double clamping the cord or without clamping the cord, when blood collection occurs within 60 s from birth in both groups. Methods A cross-sectional study was carried out, collecting data from 6884 high-risk women who were divided into two groups based on the method of cord sampling (clamped vs unclamped). Results There were significant decrease in pH and BE values into unclamped group compared with the clamped group. This difference remained significant when considering pathological blood gas analysis parameters, with a higher percentage of pathological pH or BE values in the unclamped group. Conclusion Samples from the unclamped cord alter the acid–base parameters compared to collection from the clamped cord; however, this difference does not appear to be of clinical relevance. Findings could be due to the large sample size, which allowed to achieve a high power and to investigate very small numerical changes between groups, leading to a statistically significant difference in pH and BE between samples even when we could not appreciate any clinical relevant difference of pH or BE between groups. When blood gas analysis is indicated, the priority should be given to the timing of blood collection to allow reliable results, to assess newborns status at birth and intervene when needed.

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