Akira Mukai1, Koichi Suehiro2, Aya Kimura1, Katsuaki Tanaka1, Tokuhiro Yamada1, Takashi Mori1, Kiyonobu Nishikawa1. 1. Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka City, Osaka, Japan. 2. Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka City, Osaka, Japan. Electronic address: suehirokoichi@yahoo.co.jp.
Abstract
OBJECTIVE: To assess the effect of systemic vascular resistance (SVR) on the reliability of the ClearSight system (Edwards Lifesciences, Irvine, CA) for measuring blood pressure (BP) and cardiac output (CO). DESIGN: Observational study. SETTING: University hospital. PARTICIPANTS: Twenty-five patients undergoing cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: BP, measured using ClearSight and an arterial line, and CO, measured using ClearSight and a pulmonary artery catheter, were recorded before (T1) and two minutes after phenylephrine or ephedrine administration. Bland-Altman analysis was used to compare BP and CO measurements at T1. A polar plot was used to assess trending abilities. Patients were divided into the following three groups according to the SVR index (SVRI) at T1: low (<1,200 dyne s/cm5/m2), normal (1,200-25,00 dyne s/cm5/m2), and high (>2,500 dyne s/cm5/m2). The bias in BP and CO was -4.8 ± 8.9 mmHg and 0.10 ± 0.81 L/min, respectively, which was correlated significantly with SVRI (p < 0.05). The percentage error in CO was 40.6%, which was lower in the normal SVRI group (33.3%) than the low and high groups (46.3% and 47.7%, respectively). The angular concordance rate was 96.3% and 95.4% for BP and 87.0% and 92.5% for CO after phenylephrine and ephedrine administration, respectively. There was a low tracking ability for CO changes after phenylephrine administration in the low-SVRI group (angular concordance rate 33.3%). CONCLUSION: The ClearSight system showed an acceptable accuracy in measuring BP and tracking BP changes in various SVR states; however, the accuracy of CO measurement and its trending ability in various SVR states was poor.
OBJECTIVE: To assess the effect of systemic vascular resistance (SVR) on the reliability of the ClearSight system (Edwards Lifesciences, Irvine, CA) for measuring blood pressure (BP) and cardiac output (CO). DESIGN: Observational study. SETTING: University hospital. PARTICIPANTS: Twenty-five patients undergoing cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: BP, measured using ClearSight and an arterial line, and CO, measured using ClearSight and a pulmonary artery catheter, were recorded before (T1) and two minutes after phenylephrine or ephedrine administration. Bland-Altman analysis was used to compare BP and CO measurements at T1. A polar plot was used to assess trending abilities. Patients were divided into the following three groups according to the SVR index (SVRI) at T1: low (<1,200 dyne s/cm5/m2), normal (1,200-25,00 dyne s/cm5/m2), and high (>2,500 dyne s/cm5/m2). The bias in BP and CO was -4.8 ± 8.9 mmHg and 0.10 ± 0.81 L/min, respectively, which was correlated significantly with SVRI (p < 0.05). The percentage error in CO was 40.6%, which was lower in the normal SVRI group (33.3%) than the low and high groups (46.3% and 47.7%, respectively). The angular concordance rate was 96.3% and 95.4% for BP and 87.0% and 92.5% for CO after phenylephrine and ephedrine administration, respectively. There was a low tracking ability for CO changes after phenylephrine administration in the low-SVRI group (angular concordance rate 33.3%). CONCLUSION: The ClearSight system showed an acceptable accuracy in measuring BP and tracking BP changes in various SVR states; however, the accuracy of CO measurement and its trending ability in various SVR states was poor.