Non-Invasive Estimation of Cardiac Index in Healthy Volunteers

Abstract

The primary objective was to non-invasively measure the cardiac index (CI) and associated haemodynamic parameters of healthy volunteers and their changes with age. This was a single centre, prospective, observational study of healthy volunteers aged between 20 and 59 years, using the ClearSight™ (Edwards Life Sciences, Irvine, CA, USA) device. We recorded 514 observations in 97 participants. The mean CI was 3.5 l/min/m 2 (95% confidence interval [95% CI] 3.4 to 3.7 l/min/m 2 ). The mean stroke volume index (SVI) was 47 ml/m 2 (95% CI 45 to 49 ml/m 2 ) and the mean systemic vascular resistance index was 2,242 dyne . s/cm 5 /m 2 (95% CI 2,124 to 2,365 dyne . s/cm 5 /m 2 ). There was an inverse linear relationship between increasing age and CI (P <0.0001), which decreased by 0.044 l/min/m 2 (95% CI -0.032 to -0.056 l/min/m 2 ) per year. This change was mostly due to a decrease in SVI of 0.45 ml/m 2 (95% CI 0.32 to 0.57 ml/m 2 ) per year (P <0.0001). The mean CI of young healthy humans is approximately 3.5 l/min/m 2 and declines by approximately 40 ml/min/m 2 per year, mostly due to a decline in stroke volume (SV). These findings have significant implications regarding the clinical interpretation of haemodynamic parameters and the application of these results to individual patients.

COMBED: Rapid non‐invasive Cardiac Output Monitoring Baseline assessment in adult Emergency Department patients with haemodynamic instability

“…[21][22][23] The CI, SVI and SVRI measured in 50-59-year-old healthy volunteers using the same device were 2.8 L/ min/m 2 , 39.2 mL/m 2 , and 2916 dynes s/cm 5 /m 2 , respectively. 24 In our study, the measured CI was elevated (3.5 L/ min/m 2 ) despite a lower SVI (33.5 mL/m 2 ) and was associated with a reduced SVRI. A previous study using the ClearSight™ device assessed 47 hospital-ward patients who triggered a rapid response team review for HI.…”

“…Several studies, however, have highlighted declines in CI with age 21–23 . The CI, SVI and SVRI measured in 50–59‐year‐old healthy volunteers using the same device were 2.8 L/min/m 2 , 39.2 mL/m 2 , and 2916 dynes s/cm 5 /m 2 , respectively 24 . In our study, the measured CI was elevated (3.5 L/min/m 2 ) despite a lower SVI (33.5 mL/m 2 ) and was associated with a reduced SVRI.…”

Haemodynamic monitoring during noncardiac surgery: past, present, and future

“…Therefore, there is no “normal CO”. Resting CO varies substantially among individuals – but generally decreases with age [ 136 ]. Although arterial pressure and CO are physiologically coupled, there is no clinically meaningful correlation between arterial pressure and CO in patients having surgery [ 137 ].…”

Cardiac index-guided therapy to maintain optimised postinduction cardiac index in high-risk patients having major open abdominal surgery: the multicentre randomised iPEGASUS trial

“…Cardiac output is highly variable, both within and between individuals. 9 , 10 We thus assumed that intraoperative cardiac output targets can best be individually defined after the induction of general anaesthesia. 11 As cardiac output depends on intravascular fluid status, we further assumed that postinduction cardiac output is optimal when patients are unlikely to be fluid responsive.…”