A preliminary study evaluating cardiac output measurement using Pressure Recording Analytical Method (PRAM) in anaesthetized dogs

Abstract

BackgroundHaemodynamic variations normally occur in anaesthetized animals, in relation to the animal status, administered drugs, sympathetic and parasympathetic tone, fluid therapy and surgical stimulus. The possibility to measure some cardiovascular parameters, such as cardiac output (CO), during anaesthesia would be beneficial for both the anaesthesia management and its outcome. New techniques for the monitoring of CO are aimed at finding methods which are non invasive, accurate and with good trending ability, which can be used in a clinical setting. The aim of this study was to compare the Pressure Recording Analytical Method (PRAM) with the pulmonary artery thermodilution (TD) for the measurement of cardiac output in 6 anaesthetized critically ill dogs.ResultsFifty-four pairs of CO measurements were obtained with a median (range) of 3.33 L/min (0.81–7.21) for PRAM-CO and 3.48 L/min (1.41–6.56) for TD-CO. The Bland-Altman analysis showed a mean bias of 0.17 L/min with limits of agreement (LoA) of − 0.46 to 0.81 L/min. The percentage error resulted 18.2%. The 4-quadrant plot analysis showed an acceptable concordance (93%) between the 2 methods. The polar plot showed a good trending ability with the mean angular bias of 3.9° and radial LoA ± 12.1°.ConclusionsThe PRAM resulted in good precision, acceptable concordance and good trending ability for the measure of CO in the anaesthetized dog, representing a promising alternative to thermodilution for the measurement of CO. Among all the pulse contour methods available on the market it is the only one that does not require any calibration or adjustment of the measurement. Further studies are required to verify the ability of this method to accurately measure cardiac output even during unstable hemodynamic conditions.

Intraoperative Assessment of Fluid Responsiveness in Normotensive Dogs under Isoflurane Anaesthesia

“…The PRAM is an uncalibrated pulse contour technique that has been recently validated in dogs [ 30 ] and proved to have the best trending ability among the other uncalibrated pulse contour techniques in this species, under stable haemodynamic conditions. The PRAM estimates SV and other haemodynamic parameters based on arterial pulse waveform analysis [ 47 ].…”

“…SV (mL) is estimated by measuring the area under the systolic portion of an arterial pressure curve and the variable Z. The variable Z represents all of the possible factors responsible for the dynamic impedance of the cardiovascular system, which oppose pressure wave propagation in arterial beds, and is computed from the pressure curve through a proprietary algorithm applied to each beat [ 30 , 47 ]. The PRAM technique has been reported in the literature for the assessment of the FC in infants undergoing ventricular septal defect [ 48 ].…”

“…Relevant haemodynamic monitoring was performed using the pressure recording analytical method (PRAM; Most Care; Vytech) [ 30 ]. Heart rate, SAP, DAP, MAP, SPV (%), CO (L/min), PPV (%), and SVV (%) were continuously monitored based on the following formulas: PPV (%) = 100 × (PPmax − PPmin)/(PPmax + PPmin)/2) SPV (%) = 100 × (SPmax − SPmin)/(SPmax + SPmin)/2 SVV (%) = 100 × (SV max − Svmin)/(SVmax + SVmin)/2 CO (L·min − 1) = SV × HR …”

“…Relevant haemodynamic monitoring was performed using the pressure recording analytical method (PRAM; Most Care; Vytech) [30]. Heart rate, SAP, DAP, MAP, SPV (%), CO (L/min), PPV (%), and SVV (%) were continuously monitored based on the following formulas:…”

Pulse Pressure Variation Can Predict the Hemodynamic Response to Pneumoperitoneum in Dogs: A Retrospective Study

“…The hemodynamic parameters were collected with a monitoring system based on the pressure recording analytical method technology (PRAM). This uncalibrated pulse contour technique estimates SV and other hemodynamic parameters from the analysis of the arterial pulse waveform, and has been recently validated in dogs [16]. In all cases of the study, PP was created via a Veress needle with a CO 2 insufflator (Endoflator; Karl-Storz, Tuttlingen, Germany) at an IAP of 10–11 mmHg.…”