scholarly journals Estimation of Arterial Carbon Dioxide Based on End-Tidal Gas Pressure and Oxygen Saturation

2018 ◽  
Vol 7 (9) ◽  
pp. 290 ◽  
Author(s):  
Raisa Rentola ◽  
Johanna Hästbacka ◽  
Erkki Heinonen ◽  
Per Rosenberg ◽  
Tom Häggblom ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Saturation ◽  
Partial Pressure ◽  
Traditional Method ◽  
Mean Difference ◽  
Mechanically Ventilated ◽  
Arterial Carbon Dioxide ◽  
Arterial Blood ◽  
The Mean ◽  
End Tidal

Arterial blood gas (ABG) analysis is the traditional method for measuring the partial pressure of carbon dioxide. In mechanically ventilated patients a continuous noninvasive monitoring of carbon dioxide would obviously be attractive. In the current study, we present a novel formula for noninvasive estimation of arterial carbon dioxide. Eighty-one datasets were collected from 19 anesthetized and mechanically ventilated pigs. Eleven animals were mechanically ventilated without interventions. In the remaining eight pigs the partial pressure of carbon dioxide was manipulated. The new formula (Formula 1) is PaCO2 = PETCO2 + k(PETO2 − PaO2) where PaO2 was calculated from the oxygen saturation. We tested the agreements of this novel formula and compared it to a traditional method using the baseline PaCO2 − ETCO2 gap added to subsequently measured, end-tidal carbon dioxide levels (Formula 2). The mean difference between PaCO2 and calculated carbon dioxide (Formula 1) was 0.16 kPa (±SE 1.17). The mean difference between PaCO2 and carbon dioxide with Formula 2 was 0.66 kPa (±SE 0.18). With a mixed linear model excluding cases with cardiorespiratory collapse, there was a significant difference between formulae (p < 0.001), as well as significant interaction between formulae and time (p < 0.001). In this preliminary animal study, this novel formula appears to have a reasonable agreement with PaCO2 values measured with ABG analysis, but needs further validation in human patients.

scholarly journals Recent Insights into the Measurement of Carbon Dioxide Concentrations for Clinical Practice in Respiratory Medicine

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5636
Author(s):  
Akira Umeda ◽  
Masahiro Ishizaka ◽  
Akane Ikeda ◽  
Kazuya Miyagawa ◽  
Atsumi Mochida ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Clinical Practice ◽  
Partial Pressure ◽  
Sleep Apnea Syndrome ◽  
The Body ◽  
Non Invasive ◽  
Arterial Blood ◽  
Co2 Concentrations ◽  
Partial Pressure Of Co2 ◽  
End Tidal

In the field of respiratory clinical practice, the importance of measuring carbon dioxide (CO2) concentrations cannot be overemphasized. Within the body, assessment of the arterial partial pressure of CO2 (PaCO2) has been the gold standard for many decades. Non-invasive assessments are usually predicated on the measurement of CO2 concentrations in the air, usually using an infrared analyzer, and these data are clearly important regarding climate changes as well as regulations of air quality in buildings to ascertain adequate ventilation. Measurements of CO2 production with oxygen consumption yield important indices such as the respiratory quotient and estimates of energy expenditure, which may be used for further investigation in the various fields of metabolism, obesity, sleep disorders, and lifestyle-related issues. Measures of PaCO2 are nowadays performed using the Severinghaus electrode in arterial blood or in arterialized capillary blood, while the same electrode system has been modified to enable relatively accurate non-invasive monitoring of the transcutaneous partial pressure of CO2 (PtcCO2). PtcCO2 monitoring during sleep can be helpful for evaluating sleep apnea syndrome, particularly in children. End-tidal PCO2 is inferior to PtcCO2 as far as accuracy, but it provides breath-by-breath estimates of respiratory gas exchange, while PtcCO2 reflects temporal trends in alveolar ventilation. The frequency of monitoring end-tidal PCO2 has markedly increased in light of its multiple applications (e.g., verify endotracheal intubation, anesthesia or mechanical ventilation, exercise testing, respiratory patterning during sleep, etc.).

Comparing arterial and end-tidal carbon dioxide values in hyperventilated neurosurgical patients

1995 ◽  
Vol 4 (2) ◽  
pp. 116-121 ◽  
Author(s):  
MA Christensen ◽  
J Bloom ◽  
KR Sutton
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Tension ◽  
Blood Gas ◽  
Arterial Blood Gas ◽  
Arterial Carbon Dioxide ◽  
Arterial Blood ◽  
Neurosurgical Patients ◽  
End Tidal Carbon Dioxide ◽  
Carbon Dioxide Monitoring ◽  
End Tidal

BACKGROUND: Hyperventilation is a frequently used method for inducing hypercarbia in neurosurgical patients. This practice requires careful carbon dioxide monitoring that might be replaced by a less expensive and less invasive alternative to arterial blood gas monitoring. OBJECTIVE: To determine the accuracy of end-tidal carbon dioxide monitoring in hyperventilated neurosurgical patients. METHODS: Nineteen adult patients requiring hyperventilation for the reduction of intracranial pressure following head injury or neurosurgery were enrolled from the surgical intensive care unit of a level I trauma center. A correlation design was used to compare arterial carbon dioxide tensions and end-tidal carbon dioxide measurements during specific periods; secondary analysis with bias and precision estimates was performed. Also, changes in arterial carbon dioxide tensions were compared with simultaneous changes in end-tidal carbon dioxide values. RESULTS: End-tidal carbon dioxide values showed a moderately acceptable correlation with arterial blood gas measurements. However, changes in end-tidal carbon dioxide values failed to correlate with simultaneous changes in arterial carbon dioxide tension measures. Bias and precision measures confirmed these findings. CONCLUSION: In this patient sample, changes in end-tidal carbon dioxide values did not accurately reflect changes in arterial carbon dioxide tension levels in the intensive care setting. Further technological advances in noninvasive carbon dioxide monitoring may lead to a significant cost savings over traditional arterial blood gas analysis.

An Evaluation of Transcutaneous Carbon Dioxide Partial Pressure Monitoring during Apnea Testing in Brain-dead Patients

2006 ◽  
Vol 104 (4) ◽  
pp. 701-707 ◽  
Author(s):  
Benoîit Vivien ◽  
Frédéric Marmion ◽  
Sabine Roche ◽  
Catherine Devilliers ◽  
Olivier Langeron ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Partial Pressure ◽  
Test Group ◽  
Carbon Dioxide Partial Pressure ◽  
Arterial Oxygen ◽  
Apnea Test ◽  
Transcutaneous Carbon Dioxide ◽  
Arterial Blood ◽  
The Mean ◽  
Brain Dead

Background Diagnosis of brain death usually requires an arterial carbon dioxide partial pressure (Paco2) of 60 mmHg during the apnea test, but the increase in Paco2 is unpredictable. The authors evaluated whether transcutaneous carbon dioxide partial pressure (Ptcco2) monitoring during apnea test can predict that a Paco2 of 60 mmHg has been reached. Methods The authors compared Ptcco2 measured with a transcutaneous ear sensor (V-Sign Sensor, Sentec Digital Monitoring System; SENTEC-AG, Therwil, Switzerland) and Paco2 obtained from arterial blood gas measurements in 32 clinically brain-dead patients. Results In the first 20 patients, the mean Paco2-Ptcco2 gradient was 0.7 +/- 3.6 mmHg at baseline and 8.7 +/- 7.1 mmHg after 20 min of apnea. Using receiver operating characteristic curve analysis (area under the curve: 0.983 +/- 0.013), the best threshold value of Ptcco2 to predict that a Paco2 of 60 mmHg had been reached was 60 mmHg (positive predictive value: 1.00 [0.93-1.00]). In the following 12 patients investigated with use of this Ptcco2 target value of 60 mmHg, the mean duration of the apnea test (11 +/- 4 vs. 20 +/- 0 min; P &lt; 0.001), hypercapnia (74.0 +/- 4.9 vs. 98.3 +/- 20.0 mmHg; P &lt; 0.001), acidosis (pH: 7.18 +/- 0.06 vs. 7.11 +/- 0.08; P &lt; 0.001), and decrease in arterial oxygen partial pressure (-47 +/- 44 vs. -95 +/- 89; P &lt; 0.05) at the end of the test were reduced as compared with the 20-min apnea test group. Conclusion During the apnea test in brain-dead patients, a Ptcco2 of 60 mmHg accurately predicts that a Paco2 of 60 mmHg has been reached. This may allow a reduction in the duration of the apnea test and consecutively limit occurrence of complications.

Maternal Insufflation during the Second Trimester Equivalent Produces Hypercapnia, Acidosis, and Prolonged Hypoxia in Fetal Sheep

2004 ◽  
Vol 101 (6) ◽  
pp. 1332-1338 ◽  
Author(s):  
Kenichiro Uemura ◽  
Rebecca J. McClaine ◽  
Sebastian G. de la Fuente ◽  
Roberto J. Manson ◽  
Kurt A. Campbell ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Oxygen Saturation ◽  
Partial Pressure ◽  
Uterine Blood Flow ◽  
Second Trimester ◽  
Blood Gas ◽  
Fetal Sheep ◽  
Total N ◽  
Arterial Blood

Background Anecdotal reports suggest that the second trimester is the safest time to conduct a laparoscopic procedure on a pregnant patient, but this supposition has not been tested empirically. Methods Previously instrumented preterm sheep (total n = 8) at gestational day 90 (term, 145 days) were anesthetized and then insufflated with carbon dioxide for 60 min at a pressure of 15 mmHg. Cardiovascular parameters were continuously recorded while blood gas status was determined before and at 15-min intervals during and up to 2 h after insufflation. Results Insufflation produced minimal maternal blood gas or cardiovascular changes except for a significant reduction in uterine blood flow. The decrease in perfusion increased fetal arterial blood partial pressure of carbon dioxide and decreased fetal pH, oxygen saturation, and oxygen content; there was also progressive fetal hypotension and bradycardia. After manually deflating the ewe, uterine blood flow returned to normal, and the fetal partial pressure of carbon dioxide and pH changes resolved within 1 h. However, fetal oxygen saturation and content remained depressed, and fetal cardiovascular status continued to decline during the 2-h postinsufflation monitoring period. Conclusion Previous studies with near-term sheep determined that carbon dioxide pneumoperitoneum produces respiratory acidosis but does not decrease fetal oxygenation. In contrast, the current findings indicate that in the preterm fetus, insufflation-induced hypercapnia and acidosis are accompanied by prolonged fetal hypoxia and cardiovascular depression. This result suggests that additional work should be conducted to confirm the presumed safety of conducting minimally invasive procedures during the second trimester.

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