Ultrasound dilution

Abstract

Background Cardiac output (CO) is a useful measure of myocardial performance. CO monitoring is frequently performed in critically ill adults in order to guide physicians’ treatment strategies. However, standard methods of determining CO in children are not without risk and can be problematic secondary to their invasive nature and other technical problems. COstatus® system (Transonic Systems Inc, NY, USA), which is based on ultrasound dilution technology, works off in situ catheters and uses an innocuous indicator to allow for routine measurements of cardiac output and blood volumes in pediatric patients. The purpose of this study was to validate CO measured by COstatus® with those obtained by the clinical standard technique of pulmonary artery (PAC) thermodilution. Methods This was a prospective evaluation performed at a single institution. Any child with a structurally normal heart undergoing hemodynamic evaluation in the cardiac catheterization laboratory was included. A prograde right heart catheterization was performed, and CO was first determined by using the PAC thermodilution technique. Thermodilution results were then compared with CO measurements obtained using the COstatus system. The results were analyzed by standard correlation, Bland-Altman, and Crichtley and Critchley analyses. Results Twenty-eight patients were evaluated with a median age of 8 yrs and a median weight of 31 kg. The mean thermodilution cardiac index = 3.18 L/min (+/− 1.35 L/min), and the mean COstatus® cardiac index = 3.17 L/min (+/− 1.31 L/min). Standard Pearson correlation tests revealed an excellent correlation coefficient of 0.95 (p<0.0001). Bland-Altman analysis revealed good clinical agreement with a mean difference of −0.004 L/min with a precision of 0.8 L/min/ at 2 SD. A percentage error of 25.4% was noticed in this study which is less than the clinically acceptable limit. Conclusion The ultrasound dilution technique of determining CO using the COstatus® system provides a less invasive method than the traditional pulmonary artery thermodilution for accurately determining cardiac output in children. This is the first validation of the COstatus® system in pediatric patients. Further studies are required to establish its accuracy in pediatric patients with cardiac shunts and other hemodynamically unstable conditions.

Neonatal Hemodynamics: From Developmental Physiology to Comprehensive Monitoring

“…A possible limitation could be the risk of fluid overload after multiple injections of indicator. The method is feasible in infants and children ( 87 – 89 ). Clinical studies in neonates are in progress and reports in newborns/infants seem promising ( 90 , 91 ).…”

Cardiac output measurements via echocardiography versus thermodilution: A systematic review and meta-analysis

“…Of these studies, the number of patients ranged from 6 to 89. CO measurements were performed using TTE in 19 studies[2, 13, 23, 26, 27, 41, 44–46, 49–51, 58, 64, 68, 70, 73, 75], TEE in 24 [6–8, 18, 20, 30–32, 34, 42, 47, 48, 52–57, 59–63, 77], USCOM in 14 [4, 19, 22, 25, 28, 39, 40, 43, 65–67, 69, 72, 74], UD in 4 [29, 33, 36, 71], and other types of echocardiography in 7 [10, 21, 24, 35, 37, 38, 61]. CO measurements were performed in the AA in 13 studies [2, 4, 19, 24, 27, 28, 32, 35, 37, 41, 45, 47,…”

Ultrasound dilution cardiac output and echocardiography findings in anesthetized mature alpacas (Vicugna pacos) during normotension, hypotension and hypertension

“…The sensor on the arterial side measured a dilution curve. The dilution curve was created by a change in protein concentration of blood after injection of an isotonic saline indicator bolus as it circulates through the cardiovascular system [ 9 ]. The bolus consisted of 30 ml of warmed isotonic saline rapidly injected into the venous side of the AV loop.…”

“…It utilizes peripherally placed catheters, does not involve blood loss, and uses a physiologic non-cumulative signal (isotonic fluid) [ 7 , 8 ]. The technique follows the theory of ultrasound velocity dilution, which is based on changes in blood ultrasound velocity through transient changes in blood protein concentration [ 9 ].…”