Measuring carbon dioxide tension in saline and alternative solutions: Quantification of bias and precision in two blood gas analyzers

1994 ◽  
Vol 22 (1) ◽  
pp. 96-100 ◽  
Author(s):  
David Riddington ◽  
Keith Balasubramanian Venkatesh ◽  
Thomas Clutton-Brock ◽  
Julian Bion
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Tension ◽  
Blood Gas ◽  
Alternative Solutions

Clinical evaluation of an instrument to measure carbon dioxide tension at the oxygenator gas outlet in cardiopulmonary bypass

Perfusion ◽  
2006 ◽  
Vol 21 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Frode Kristiansen ◽  
Jan Olav Høgetveit ◽  
Thore H Pedersen
Keyword(s):  
Carbon Dioxide ◽  
Cardiopulmonary Bypass ◽  
Venous Blood ◽  
Carbon Dioxide Tension ◽  
Circuit Board ◽  
Separate Analysis ◽  
Blood Gas ◽  
Arterial Blood ◽  
Gas Measurement ◽  
Venous Blood Gas

This paper presents the clinical testing of a new capno-graph designed to measure the carbon dioxide tension at the oxygenator exhaust outlet in cardiopulmonary bypass (CPB). During CPB, there is a need for reliable, accurate and instant estimates of the arterial blood CO2 tension (PaCO2) in the patient. Currently, the standard practice for measuring PaCO2 involves the manual collection of intermittent blood samples, followed by a separate analysis performed by a blood gas analyser. Probes for inline blood gas measurement exist, but they are expensive and, thus, unsuitable for routine use. A well-known method is to measure PexCO2, ie, the partial pressure of CO2 in the exhaust gas output from the oxygenator and use this as an indirect estimate for PaCO2. Based on a commercially available CO2 sensor circuit board, a laminar flow capnograph was developed. A standard sample line with integrated water trap was connected to the oxygenator exhaust port. Fifty patients were divided into six different groups with respect to oxygenator type and temperature range. Both arterial and venous blood gas samples were drawn from the CPB circuit at various temperatures. Alfa-stat corrected pCO2 values were obtained by running a linear regression for each group based on the arterial temperature and then correcting the PexCO2 accordingly. The accuracy of the six groups was found to be (±SD): ±4.3, ±4.8, ±5.7, ±1.0, ±3.7 and ±2.1%. These results suggest that oxygenator exhaust capnography is a simple, inexpensive and reliable method of estimating the PaCO2 in both adult and pediatric patients at all relevant temperatures.

СIRCADIAN RHYTHMS OF BLOOD GAS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

2016 ◽  
Vol 1 (60) ◽  
pp. 34-38
Author(s):  
Горячева ◽  
Svetlana Goryacheva ◽  
Приходько ◽  
Olga Prikhodko ◽  
Кострова ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Circadian Rhythm ◽  
Respiratory System ◽  
Carbon Dioxide Tension ◽  
Capillary Blood ◽  
Chronic Obstructive ◽  
Gas Composition ◽  
Blood Gas ◽  
Healthy Individuals ◽  
Partial Oxygen

Chronobiological aspects of blood gas composition in 24 patients with COPD were studied. To achieve this goal, the gas composition of the arterialized capillary blood simultaneously with the investigation of respiratory function was studied with an interval of 6 hours over 2 days. In healthy individuals and patients with mild COPD two types of gas composition of blood biorhythm – daytime and nighttime – were found. In patients with moderate, severe and very severe disease 3 types of biorhythm of partial oxygen and carbon dioxide tension – morning time, noontime and evening time were registered. In healthy individuals and patients with mild COPD gas composition of blood was characterized by significant degrees of freedom in relation to functioning of the respiratory system, which indicated the stored processes of adaptation to changing conditions of the external and internal environment. In patients with moderate, severe and very severe COPD at the moment of acrophase of circadian rhythm of lung function maximum partial oxygen pressure in the arterialized capillary blood was observed. During the batiphaze of circadian rhythm of the respiratory system the highest values of the partial carbon dioxide tension were revealed. Thus, it was found out that with the growth of the severity of the disease in patients with COPD abnormal rhythms of blood gas composition are registered; the dependence of circadian rhythm of blood gas composition on the functioning of the respiratory apparatus increases.

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.

Development of an instrument to indirectly monitor arterial pCO2 during cardiopulmonary bypass

Perfusion ◽  
2006 ◽  
Vol 21 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Jan Olav Høgetveit ◽  
Frode Kristiansen ◽  
Thore H Pedersen
Keyword(s):  
Carbon Dioxide ◽  
Cardiopulmonary Bypass ◽  
Temperature Sensor ◽  
Carbon Dioxide Tension ◽  
Temperature Correction ◽  
Blood Gas ◽  
Sensor Module ◽  
New Instrument ◽  
Heart Lung Machine ◽  
Lung Machine

Arterial blood carbon dioxide tension (PaCO2) during cardiopulmonary bypass (CBP) is important to the conduct of perfusion with alpha-stat or pH-stat strategy. Temperature changes during CBP complicate any attempts to monitor carbon dioxide tension in the exhaust outlet of an oxygenator (PexCO2) because CO2 becomes more soluble with decreasing temperatures. Normally, this would have been the obvious and easy choice of method to indirectly measure the patient’s PaCO2. Several tests have been performed with ordinary capnographs modified to measure pCO2 at the oxygenator exhaust gas port. These tests have shown varying degrees of precision ( Br J Anaesth 1999; 82(6): 843-46; J Extra-Corpor Technol 2003; 35(3): 218-23; Br J Anaesth 2000; 84: 536; J Extra-Corpor Technol 1994; 26: 64-67). Some of the best results have been achieved by Potger et al. ( J Extra-Corpor Technol 2003; 35(3): 218-23), who found a strong correlation between the arterial temperature-corrected PexCO2 when using a standard capnograph monitoring the PaCO2 measured from a blood gas analyser (PbCO2). Our group has developed a new instrument, especially designed for oxygenator gas exhaust monitoring. The new instrument has automatic temperature correction, enabling it to show both original and corrected pCO2 values, simultaneously. Ordinary capnograph functions, such as zeroing, flow control and calibration routines, are included. The solution consists of a pCO2 sensor module, a temperature sensor, a water trap and a dedicated PC mounted on a heart-lung machine. Since the heart-lung machine was already equipped with a computer for data logging and a temperature sensor, only a box containing the pCO2 sensor module and the water trap had to be added. The PC uses a specially written program designed to collect data, make the necessary calculations and display the results on the computer screen. A temperature correction was developed based on a linear regression analysis for a data-set of 15 patients, assuming that the deviation between the measured PexCO2 from the oxygenator exhaust outlet and the PbCO2 from the blood gas analyser was linearly dependent on arterial temperature alone. Eighty-six blood gas samples were compared to the corrected PexCO2 values. The final product displayed good qualities of stability and was accurate when temperature fluctuated from 32 to 388C, even during rewarming, which has been reported to be a problem for other PexCO2 investigations ( J Extra-Corpor Technol 2003; 35(3): 218-23).

Validation of transcutaneous carbon dioxide monitoring using an artificial lung during adult pulsatile cardiopulmonary bypass

2021 ◽  
pp. 039139882098785
Author(s):  
Lawrence Garrison ◽  
Jeffrey B Riley ◽  
Steve Wysocki ◽  
Jennifer Souai ◽  
Hali Julick
Keyword(s):  
Carbon Dioxide ◽  
Cardiopulmonary Bypass ◽  
Gold Standard ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Artificial Lung ◽  
Blood Gas ◽  
Median Difference ◽  
Transcutaneous Carbon Dioxide ◽  
Arterial Blood

Measurements of transcutaneous carbon dioxide (tcCO2) have been used in multiple venues, such as during procedures utilizing jet ventilation, hyperbaric oxygen therapy, as well as both the adult and neo-natal ICUs. However, tcCO2 measurements have not been validated under conditions which utilize an artificial lung, such cardiopulmonary bypass (CPB). The purpose of this study was to (1) validate the use of tcCO2 using an artificial lung during CPB and (2) identify a location for the sensor that would optimize estimation of PaCO2 when compared to the gold standard of blood gas analysis. tcCO2 measurements ( N = 185) were collected every 30 min during 54 pulsatile CPB procedures. The agreement/differences between the tcCO2 and the PaCO2 were compared by three sensor locations. Compared to the earlobe or the forehead, the submandibular PtcCO2 values agreed best with the PaCO2 and with a median difference of –.03 mmHg (IQR = 5.4, p < 0.001). The small median difference and acceptable IQR support the validity of the tcCO2 measurement. The multiple linear regression model for predicting the agreement between the submandibular tcCO2 and PaCO2 included the SvO2, the oxygenator gas to blood flow ratio, and the native perfusion index ( R2 = 0.699, df = 1, 60; F = 19.1, p < 0.001). Our experience in utilizing tcCO2 during CPB has demonstrated accuracy in estimating PaCO2 when compared to the gold standard arterial blood gas analysis, even during CO2 flooding of the surgical field.

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