Year: 2021
Type: conference-abstract
Abstract: RATIONALE: Arterial PCO 2 (P a CO 2 ) has been accurately estimated from end-tidal PCO 2 (P ET CO 2 ) during exercise in healthy young adults by using a correction equation developed by Jones and colleagues (i.e., P J CO 2 =5.5+0.9xP ET CO 2 -2.1xtidal volume). The validity of the Jones correction equation has not been investigated in patients with heart failure with preserved ejection fraction (HFpEF); however, patients with HFpEF exhibit changes in pulmonary function and gas exchange that could impact the predictability of P a CO 2 from P J CO 2 . We evaluated the accuracy of P a CO 2 estimations from P ET CO 2 and P J CO 2 at rest and during exercise in a cohort of patients with HFpEF. METHODS: P ET CO 2 , P J CO 2 , and P a CO 2 values were evaluated from the first 8 patients with HFpEF admitted to the study (age: 694y; BMI: 37.46.1kg/m 2 ; V̇O 2peak : 1.100.41L/min; ejection fraction: 542%; peak PCWP: 32.86.1mmHg; five women/three men). P ET CO 2 was measured from expired gases simultaneously with temperature-corrected arterial blood gases collected from a radial artery catheter at rest, constant-load exercise (at 20W), and peak exercise. Mean differences were analyzed with paired t-tests and relationships between the estimated P a CO 2 values (i.e., P ET CO 2 and P J CO 2 ) and measured P a CO 2 were analyzed using Pearson correlation coefficients. RESULTS: P ET CO 2 was not significantly different from P a CO 2 at rest (0.12.2 Torr, p=0.965), 20W (0.41.4 Torr, p=0.503), and peak exercise (1.41.9 Torr, p=0.101), and P ET CO 2 and P a CO 2 were significantly correlated (all p<0.001) at rest (r 2 =0.56), 20 W (r 2 =0.78), and peak exercise (r 2 =0.56). While P J CO 2 was not significantly different from P a CO 2 at rest (0.22.1 Torr, p=0.879) and 20 W (-0.41.4 Torr, p=0.499), P J CO 2 was significantly different (p=0.013) from P a CO 2 at peak exercise (2.52.0 Torr). Also, P J CO 2 and P a CO 2 were significantly correlated (all p<0.001) at rest (r 2 =0.56), 20W (r 2 =0.81), and peak exercise (r 2 =0.91). CONCLUSIONS: Our findings demonstrate that both P ET CO 2 and P J CO 2 provide reasonable estimates of P a CO 2 at rest and during submaximal constant-load exercise whereas P ET CO 2 may provide a better estimate of P a CO 2 than P J CO 2 does at peak exercise in patients with HFpEF. Our findings also support the notion that clinicians and physiologists can obtain reasonable non-invasive estimations of P a CO 2 in patients with HFpEF by using P ET CO 2 , which permits the use of repeated measures during cardiopulmonary exercise testing wherein the risks associated with arterial puncture are negated.
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Funder: National Institutes of Health
OpenAlex ID: W4256369232