Comparison of cardiac output and blood volumes in intrathoracic compartments measured by ultrasound dilution and transpulmonary thermodilution methods

Abstract

CO measured by COstatus was found to be equivalent and hence interchangeable with PiCCO in this study population. COstatus blood volumes were found to be within the expected physiological range whilst PiCCO blood volumes were significantly higher, which was also observed in other studies. Future studies using 3D echo/MRI are required to validate these blood volumes.

Comparison of Transpulmonary Thermodilution and Ultrasound Dilution Technique: Novel Insights into Volumetric Parameters from an Animal Model

“…The Bland-Altman approach [1] and percentage error for each set of data [31] confirmed this disagreement by exceeding 30%. These findings are in line with a study in adults that documented nearly 2.5 times greater thoracic and end-diastolic blood volumes measured with TPTD than with UDT [13]. There are two explanations for the discrepancies in the volumetric parameters between both indicator dilution methods.…”

“…According to Critchley and Critchley [5], limits of agreement up to ± 30% should be accepted for equivalence of two methods; thus, we used Bland-Altman analysis [1] for comparison of CO. Over a wide range of CO values (1.22-3.18 l/min) specific for infants and small children, we found the limits of agreement to be far lower than the requested 30% with a percentage error of 17.3% and 13.0 ± 8.9%, respectively, for each set of data. This is consistent with a previous study comparing CO between TPTD and UDT in adults over a range of 3.65-16.3 l/min, where a percentage error of 20% was found [13]. The excellent agreement between CO measurements might be due to the fact that both methods are based on indicator dilution methods, and both use the Stewart-Hamilton equation for CO calculation.…”

“…CO measurements using UDT have been compared with ultrasound flow probes in a pediatric animal model [9] and with thermodilution by pulmonary artery catheter in children [6], adults [37], and piglets [7]. These studies showed an excellent correlation and a small bias for CO determined by UDT compared with reference techniques [6,7,13,16,37]. Furthermore, volumetric parameters for the neonatal and pediatric range have been validated in an in vitro simulation [16].…”

“…Furthermore, volumetric parameters for the neonatal and pediatric range have been validated in an in vitro simulation [16]. Recently, a comparative study between TPTD and UDT in adults showed equivalent results for CO measurements, but volumetric parameters differed significantly between both methods [13].…”

“…Today this technique is limited by existing catheter sizes [24] and the risk of thrombotic occlusion after insertion of the femoral artery thermodilution catheter [12], particularly in small children weighing \15 kg. Recently introduced minimally invasive ultrasound dilution technology (UDT) offers a promising alternative because it can be used in patients of any age and weight with already existing peripheral arterial and central venous catheters [6,8,13,16]. Body-temperature isotonic saline is used as the indicator, and changes of blood ultrasound velocity caused by isotonic saline are measured [16].…”