Accuracy of Transcutaneous Carbon Dioxide Tension Measurements during Cardiopulmonary Exercise Testing

Abstract

Background: Measurements of transcutaneous carbon dioxide tension (PtcCO₂) with current devices are proven to provide clinically acceptable agreement with measurements of partial arterial carbon dioxide tension (PaCO₂) in several settings but not during cardiopulmonary exercise testing (CPET). Objectives: The primary objective of this study was to investigate the agreement between PaCO₂ and PtcCO₂ measurements (using a Tosca 500 with a Tosca sensor 92) during CPET. A secondary objective was to investigate the agreement between arterial and transcutaneous oxygen saturation (SaO₂, SpO₂) as measured with this sensor during CPET. Methods: In patients with various pulmonary diseases, PtcCO₂ and SpO₂ were continuously measured and compared with arterial blood gas samples during CPET. A maximum bias of 0.5 kPa and 95% limits of agreement (LOA) of 1 kPa between carbon dioxide pressure (PCO₂) measurements were determined as clinically acceptable. Results: In total 101 ‘paired’ arterial and transcutaneous measurements were obtained from 21 patients. Bias between PaCO₂ and PtcCO₂ was –0.03 kPa with LOA from –0.78 to 0.71 kPa. Bias between SaO₂ and SpO₂ was –1.0% with LOA from –2.83 to 0.83%. Conclusions: Transcutaneous estimations of PCO₂ and SpO₂ are accurate and can be used in CPET, circumvening the need for arterial cannulation.

Validation of a Transcutaneous CO₂ Monitor in Adult Patients with Chronic Respiratory Failure

“…Earlier studies have also assessed the TOSCA system in different settings, but none have done this in a non-supervised continual measurement, while asleep, as in our study [3,7,8,9,10,11,12,13,14,15,18]. All referred studies performed measurements with a reported mean difference (bias) between PaCO 2 and PtcCO 2 ranging from 0.4 to 1.0 kPa (3 to 7.5 mm Hg).…”

“…A maximum bias of <2 and 95% LOA of 4% were determined as clinically acceptable between arterial oxygen and transcutaneous saturation. To determine whether transcutaneous measurements differ significantly from the arterial values at the same time point we performed a Student’s paired t test [10]. Analysis of variance for repeated measurements was used to determine changes from one time point to the next.…”

“…While Storre et al [7] used the SenTec digital monitor, Janssens et al [8] showed that transcutaneous carbon dioxide (PtcCO 2 ) can be measured with the Radiometer TCM-3 capnograph during 8 h and a sensor temperature of 43°C without recalibration. The TOSCA® monitor was used in both the acute setting of non-invasive ventilation for exacerbations of COPD [9] and during cardiopulmonary exercise testing [10]. Transcutaneous monitors have been evaluated in many settings like anesthetised children [11], critically ill adults [12], during major surgery [13], in newborns [14] and in sleep studies [15].…”

Propofol Safety in Bronchoscopy: Prospective Randomized Trial Using Transcutaneous Carbon Dioxide Tension Monitoring

“…Studies report a good correlation of PcCO 2 values with arterial blood gas measurements [16,17,18,19]. Similar to medical thoracoscopy and colonoscopy, bronchoscopy is also associated with an increase in PcCO 2 [17,19,20].…”

Evaluation of a System for Transcutaneous Long-Term Capnometry

“…The system has been used in neonatological intensive care and in adult patients with acute respiratory or cardiac failure or during cardiopulmonary exercise testing [8,22,23,24]. The examinations consistently show a good correlation between Pa CO 2 and tcP CO 2 with a mean difference of 3 mm Hg.…”