• Tomoyuki Tobushi, Kazuyuki Matsushita, Kouta Funakoshi, Kazuhiro Sakai, Manabu Akamatsu, Yasuko Yoshioka, Takeshi Tohyama, Masayuki Hirose, Ryo Nakamura, Toshiaki Kadokami, and AndoShin-IchiSI0000-0002-2796-0621Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan..
• Department of Cardiovascular Medicine, Saiseikai Futsukaichi Hospital, Chikushino, Japan.
• Physiol Rep. 2020 Nov 1; 8 (21): e14632.

AbstractAs 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.© 2020 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.

23 keywords...

hide…