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.).

Cardiopulmonary and acid–Base effects of desflurane and sevoflurane in spontaneously breathing cats

2005 ◽  
Vol 7 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Almir Pereira Souza ◽  
Piedad Natalia Henao Guerrero ◽  
Celina Tie Nishimori ◽  
Danielli Parrilha Paula ◽  
Paulo Sergio Patto Santos ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Partial Pressure ◽  
Arterial Oxygen Saturation ◽  
Respiratory Acidosis ◽  
Ion Concentration ◽  
Arterial Oxygen ◽  
Normal Limits ◽  
Arterial Blood ◽  
Short Period ◽  
End Tidal

The cardiopulmonary effects of desflurane and sevoflurane anesthesia were compared in cats breathing spontaneously. Heart (HR) and respiratory (RR) rates; systolic (SAP), diastolic (DAP) and mean arterial (MAP) pressures; partial pressure of end tidal carbon dioxide (PETCO2), arterial blood pH (pH), arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2); base deficit (BD), arterial oxygen saturation (SaO2) and bicarbonate ion concentration (HCO3) were measured. Anesthesia was induced with propofol (8±2.3 mg/kg IV) and maintained with desflurane (GD) or sevoflurane (GS), both at 1.3 MAC. Data were analyzed by analysis of variance (ANOVA), followed by the Tukey test ( P<0.05). Both anesthetics showed similar effects. HR and RR decreased when compared to the basal values, but remained constant during inhalant anesthesia and PETCO2 increased with time. Both anesthetics caused acidemia and hypercapnia, but BD stayed within normal limits. Therefore, despite reducing HR and SAP (GD) when compared to the basal values, desflurane and sevoflurane provide good stability of the cardiovascular parameters during a short period of inhalant anesthesia (T20–T60). However, both volatile anesthetics cause acute respiratory acidosis in cats breathing spontaneously.

scholarly journals The Relationship between Oxygenator Exhaust Pco2 and Arterial Pco2 During Hypothermic Cardiopulmonary Bypass

2005 ◽  
Vol 33 (4) ◽  
pp. 457-461 ◽  
Author(s):  
J. M. Graham ◽  
N. M. Gibbs ◽  
W. M. Weightman ◽  
M. R. Sheminant
Keyword(s):  
Carbon Dioxide ◽  
Cardiopulmonary Bypass ◽  
Partial Pressure ◽  
Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Limits Of Agreement ◽  
Hypothermic Cardiopulmonary Bypass ◽  
Arterial Blood ◽  
End Tidal Carbon Dioxide ◽  
End Tidal

During cardiopulmonary bypass the partial pressure of carbon dioxide in oxygenator arterial blood (Paco2) can be estimated from the partial pressure of gas exhausting from the oxygenator (PEco2). Our hypothesis is that PEco2 may be used to estimate Paco2 with limits of agreement within 7 mmHg above and below the bias. (This is the reported relationship between arterial and end-tidal carbon dioxide during positive pressure ventilation in supine patients.) During hypothermic (28-32°C) cardiopulmonary bypass using a Terumo Capiox SX membrane oxygenator, 80 oxygenator arterial blood samples were collected from 32 patients during cooling, stable hypothermia, and rewarming as per our usual clinical care. The Paco2 of oxygenator arterial blood at actual patient blood temperature was estimated by temperature correction of the oxygenator arterial blood sample measured in the laboratory at 37°C. PEco2 was measured by connecting a capnograph end-to-side to the oxygenator exhaust outlet. We used an alpha-stat approach to cardiopulmonary bypass management. The mean difference between PEco2 and Paco2 was 0.6 mmHg, with limits of agreement (±2 SD) between -5 to +6 mmHg. PEco2 tended to underestimate Paco2 at low arterial temperatures, and overestimate at high arterial temperatures. We have demonstrated that PEco2 can be used to estimate Paco2 during hypothermic cardiopulmonary bypass using a Terumo Capiox SX oxygenator with a degree of accuracy similar to that associated with the use of end-tidal carbon dioxide measurement during positive pressure ventilation in anaesthetized, supine patients.

scholarly journals A Persistently High End-Tidal Carbon Dioxide Value: Can This Be Spurious?

2019 ◽  
Vol 07 (02) ◽  
pp. 104-106
Author(s):  
Barkha Bindu ◽  
Gyaninder P. Singh ◽  
Varun Jain ◽  
Arvind Chaturvedi
Keyword(s):  
Carbon Dioxide ◽  
Unusual Case ◽  
Clinical Observation ◽  
Standard Of Care ◽  
Non Invasive ◽  
Correct Placement ◽  
Arterial Blood ◽  
End Tidal Carbon Dioxide ◽  
Carbon Dioxide Co2 ◽  
End Tidal

AbstractEnd-tidal carbon dioxide (EtCO2) monitoring has now become the standard of care not only during anesthesia but also in intensive care units for patients on mechanical ventilation, emergency department, and pre-hospital settings to confirm and monitor the correct placement of endotracheal tube. It is a non-invasive and continuous method of measuring exhaled carbon dioxide (CO2). Continuous waveform capnography measures EtCO2 and monitors ventilation. EtCO2 often correlates with partial pressure of carbon dioxide in arterial blood (PaCO2) and is a reliable indicator of PaCO2. A rise in EtCO2 often implies increased production of CO2 or decreased excretion (rebreathing, decrease ventilation) of CO2. We report an unusual case where the monitor malfunction per se lead to spuriously increased EtCO2 values without any clinical cause and did not correlate with PaCO2, thereby re-emphasizing that various monitors must always be interpreted in correlation with clinical observation.

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 217 The end-tidal and arterial carbon dioxide gradient in serious traumatic brain injury after pre-hospital emergency anaesthesia: a retrospective observational study

2020 ◽  
Vol 37 (12) ◽  
pp. 847.1-847
Author(s):  
James Price ◽  
Daniel Sandbach ◽  
Ari Ercole ◽  
Alastair Wilson ◽  
Ed Barnard
Keyword(s):  
Carbon Dioxide ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Thoracic Injury ◽  
Secondary Brain Injury ◽  
Hospital Emergency ◽  
Hospital Arrival ◽  
Arterial Blood ◽  
End Tidal ◽  
Emergency Anaesthesia

Aims/Objectives/BackgroundIn the United Kingdom (UK), 20% of patients with severe traumatic brain injury (TBI) receive pre-hospital emergency anaesthesia (PHEA). Current guidance recommends an end-tidal carbon dioxide (ETCO2) of 4.0–4.5kPa to achieve a low-normal arterial partial pressure of CO2 (PaCO2), and reduce secondary brain injury. This recommendation assumes a 0.5kPa ETCO2-PaCO2 gradient. However, the gradient in the acute phase of TBI is unknown. Our primary aim was to report the ETCO2-PaCO2 gradient of TBI patients at hospital arrival.Methods/DesignA retrospective cohort study of adult patients with serious TBI, who received a PHEA by a pre-hospital critical care team in the East of England between 1st April 2015 to 31st December 2017. Linear regression was performed to test for correlation and reported as R-squared (R2). A Bland-Altman plot was used to test for paired ETCO2 and PaCO2 agreement and reported with 95% confidence intervals (95%CI). ETCO2-PaCO2 gradient data were compared with a two-tailed, unpaired, t-test.Results/Conclusions107 patients were eligible for inclusion. Sixty-seven patients did not receive a PaCO2 sample within 30 minutes of hospital arrival and were therefore excluded. Forty patients had complete data and were included in the final analysis; per protocol.The mean ETCO2-PaCO2 gradient was 1.7 (±1.0) kPa, with only moderate correlation of ETCO2 and PaCO2 at hospital arrival (R2=0.23, p=0.002). The Bland-Altman bias was 1.7 (95%CI 1.4–2.0) kPa with upper and lower limits of agreement of 3.6 (95%CI 3.0–4.1) kPa and -0.2 (95%CI -0.8–0.3) kPa respectively. There was no significant gradient correlation in patients with a co-existing serious thoracic injury (R2=0.13, p=0.10), and this cohort had a larger ETCO2-PaCO2 gradient, 2.0 (±1.1) kPa, p=0.01. Patients who underwent pre-hospital arterial blood sampling had an arrival PaCO2 of 4.7 (±0.2) kPa.Lower ETCO2 targets than previously recommended may be safe and appropriate. The use of pre-hospital PaCO2 measurement is advocated.

scholarly journals Non-invasive positive pressure ventilation in acute hypercapnic respiratory failure: clinical experience of a respiratory ward

2004 ◽  
Vol 61 (2) ◽  
Author(s):  
R. Scala ◽  
M. Naldi ◽  
I. Archinucci ◽  
G. Coniglio
Keyword(s):  
Clinical Practice ◽  
Respiratory Failure ◽  
Standard Therapy ◽  
Positive Pressure Ventilation ◽  
Controlled Trial ◽  
Positive Pressure ◽  
Hypercapnic Respiratory Failure ◽  
Non Invasive ◽  
Arterial Blood ◽  
Acute Hypercapnic Respiratory Failure

Background: Although a controlled trial demonstrated that non-invasive positive pressure ventilation (NIV) can be successfully applied to a respiratory ward (RW) for selected cases of acute hypercapnic respiratory failure (AHRF), clinical practice data about NIV use in this setting are limited. The aim of this observational study is to assess the feasibility and efficacy of NIV applied to AHRF in a RW in everyday practice. Methods: Twenty-two percent (216/984) of patients consecutively admitted for AHRF to our RW in Arezzo (years: 1996-2003) received NIV in addition to standard therapy, according to pre-defined routinely used criteria. Tolerance, effects upon arterial blood gases (ABG), success rate (avoidance a priori criteria for intubation) and predictors of failure of NIV were analysed. Results: Nine patients (4.2%) were found to be intolerant to NIV, while the remaining 207 (M: 157, F: 50; mean (SD) age: 73.2 (8.9) yrs; COPD: 71.5%) were ventilated for &gt;1 hour. ABG significantly improved after two hours of NIV (pH: 7.32 (0.06) versus median (Interquartiles) 7.28 (7.24-7.31), p&lt;0.0001; PaCO2: 71.9 (13.5) mmHg versus 80.0 (15.2) mmHg, p&lt;0.0001; PaO2/FiO2: 212 (66) versus 184 (150-221), p&lt;0.0001). NIV succeeded in avoiding intubation in 169/207 patients (81.6%) with hospital mortality of 15.5%. NIV failure was independently predicted by Activity of Daily Living score, pneumonia as cause of AHRF and Acute Physiology and Chronic Health Evaluation III score. Conclusions: In clinical practice NIV is feasible, effective in improving ABG and useful in avoiding intubation in most AHRF episodes that do not respond to the standard therapy managed in an RW adequately trained in NIV.

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