TY - JOUR
T1 - Local temperature control improves the accuracy of cardiac output estimation using lung-to-finger circulation time after breath holding
AU - Tobushi, Tomoyuki
AU - Matsushita, Kazuyuki
AU - Funakoshi, Kouta
AU - Sakai, Kazuhiro
AU - Akamatsu, Manabu
AU - Yoshioka, Yasuko
AU - Tohyama, Takeshi
AU - Hirose, Masayuki
AU - Nakamura, Ryo
AU - Kadokami, Toshiaki
AU - Ando, Shin ichi
N1 - Funding Information:
SA is receiving unrestricted funding from Philips‐Respironics Inc. and Teijin Home Healthcare.
Publisher Copyright:
© 2020 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society
PY - 2020/11
Y1 - 2020/11
N2 - As timely measurement of the cardiac index (CI) is one of the key elements in heart failure management, a noninvasive, simple, and inexpensive method of estimating CI is keenly needed. We attempted to develop a new device that can estimate CI from the data of lung-to-finger circulation time (LFCT) obtained after a brief breath hold in the awake state. First, we attempted to estimate CI from the LFCT value by utilizing the correlation between 1/LFCT and CI estimated with MRI. Although we could obtain LFCT from 45 of 53 patients with cardiovascular diseases, we could not find the anticipated relation between 1/LFCT and CI. However, we realized that when we adopted only LFCT from patients with a finger temperature of ≥31°C, we could obtain a consistent and clear correlation with CI (correlation coefficient, r =.81). Thus, we next measured LFCT before and after warming the forearm. We found that LFCT decreased after the local temperature increased (from 27.5 ± 13.6 to 18.4 ± 5.3 s, p < 0.01). The correlation between the inverse of LFCT and CI improved after warming (1/LFCT vs. CI, from r =.69 to r =.82). The final Bland–Altman analysis between the measured and estimated CI values revealed that the bias and precision were −0.05 and 0.37 L min−1 m−2, respectively, and the percentage error was 34.3%. This study clarified that estimating CI using a simple measurement of LFCT is feasible in most patients and a low fingertip temperature strongly affects the CI-1/LFCT relationship, causing an error that can be corrected by proper local warming.
AB - As timely measurement of the cardiac index (CI) is one of the key elements in heart failure management, a noninvasive, simple, and inexpensive method of estimating CI is keenly needed. We attempted to develop a new device that can estimate CI from the data of lung-to-finger circulation time (LFCT) obtained after a brief breath hold in the awake state. First, we attempted to estimate CI from the LFCT value by utilizing the correlation between 1/LFCT and CI estimated with MRI. Although we could obtain LFCT from 45 of 53 patients with cardiovascular diseases, we could not find the anticipated relation between 1/LFCT and CI. However, we realized that when we adopted only LFCT from patients with a finger temperature of ≥31°C, we could obtain a consistent and clear correlation with CI (correlation coefficient, r =.81). Thus, we next measured LFCT before and after warming the forearm. We found that LFCT decreased after the local temperature increased (from 27.5 ± 13.6 to 18.4 ± 5.3 s, p < 0.01). The correlation between the inverse of LFCT and CI improved after warming (1/LFCT vs. CI, from r =.69 to r =.82). The final Bland–Altman analysis between the measured and estimated CI values revealed that the bias and precision were −0.05 and 0.37 L min−1 m−2, respectively, and the percentage error was 34.3%. This study clarified that estimating CI using a simple measurement of LFCT is feasible in most patients and a low fingertip temperature strongly affects the CI-1/LFCT relationship, causing an error that can be corrected by proper local warming.
UR - http://www.scopus.com/inward/record.url?scp=85095802606&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85095802606&partnerID=8YFLogxK
U2 - 10.14814/phy2.14632
DO - 10.14814/phy2.14632
M3 - Article
C2 - 33159838
AN - SCOPUS:85095802606
VL - 8
JO - Physiological Reports
JF - Physiological Reports
SN - 2051-817X
IS - 21
M1 - e14632
ER -