A Performance Evaluation of Eight Geometrically Different 10 Fr Pediatric Arterial Cannulae Under Pulsatile and Nonpulsatile Perfusion Conditions in an Infant Cardiopulmonary Bypass Model

Abstract

This investigation compared pressure drops and surplus hemodynamic energy (SHE) levels in eight commercially available pediatric aortic cannulae (10 Fr) with different geometries during pulsatile and nonpulsatile perfusion conditions in an in vitro infant model of cardiopulmonary bypass. For each trial, the cannula was placed at the distal end of the arterial line, and the insertion tip was fixed to the inlet of the simulated patient. The pseudo patient was subjected to seven pump flow rates ranging from 400 to 1000 ml/min (at 100 ml/min increments), and the mean arterial pressure was set at a constant 40 mm Hg via Hoffman clamp. Of the eight cannulae, the Surgimedics and THI models had significantly larger pressure drops (48.8 +/- 0.3 mm Hg and 48.3 +/- 1.4 mm Hg, respectively; 600 ml/min pulsatile) compared with the RMI cannula (27.6 +/- 1.2 mm Hg; 600 ml/min pulsatile), which created, on average, half of the pressure drop seen in the poorest performing cannulae. When perfusion mode was switched from nonpulsatile to pulsatile, there was a 7-9 fold increase in delivery of SHE recorded at both the pre- and postcannulae sites, regardless of which cannula was being tested. Despite being classified under the same size (10 Fr), these eight cannulae were found to vary considerably in length, inner diameter, and geometrical design. The results suggest that these differences can have a significant impact on pressure drops, as well as generation and delivery of SHE. Furthermore, it was found that pulsatile perfusion produced more "extra" hemodynamic energy when compared with nonpulsatile perfusion, regardless of cannula model.

Improved Cerebral Oxygen Saturation and Blood Flow Pulsatility With Pulsatile Perfusion During Pediatric Cardiopulmonary Bypass

“…TCD was used to record cerebral blood flow waveforms generated by pulsatile and nonpulsatile flow settings, which were analyzed computationally to yield Gosling's PI values for subsequent statistical analysis. Previous research has shown the challenges of generating pulsatile flow with small diameter aortic cannulae (16); PI data presented below enables quantitative assessment of the quality of pulsatile perfusion attained.…”

Measurement of Hemodynamic Energy at Different Vessels in an Adult Swine Model

“…Thus, an aortic cannula that produces favorable results in terms of pressure drops and delivery of pulsatile energy must be carefully chosen to achieve physiologic pulsatile flow. 13 Even when a proper circuit is chosen, it is inevitable that most of the hemodynamic energy is damped by the circuit. In this study, we focused on the actual amount of hemodynamic energy delivered to end organ vessels in an in vivo model.…”

“…Investigators have been using different extracorporeal circuits including different oxygenators, filters, venous and arterial cannulas, and coating material. [12][13][14][15] The use of suboptimal extracorporeal circuits has confused results as well. Most of the hemodynamic energy is lost by extracorporeal circuit components, including the hollow fiber membrane oxygenator, arterial filter, arterial cannula, purge line of the arterial filter, and the length of the arterial tubing.…”

“…16 -18 Thus, a number of studies have been performed to determine the optimal extracorporeal circuit, minimizing the loss of hemodynamic energy. 12,13,19,20 However, these studies have mostly used in vitro pediatric cardiopulmonary bypass (CPB) models. According to our knowledge, there have been no studies that have measured hemodynamic energy at different vessels separately in an in vivo adult model.…”

Computational Fluid Dynamics Analysis of Thrombosis Potential in Left Ventricular Assist Device Drainage Cannulae

“…In the past, cannulae have been studied experimentally, to determine pressure drops and hemodynamic energy 21 and in vivo , to investigate biocompatibility and blood damage 12,13. There have also been several numerical studies: parameterized models have been used to investigate the influence of side holes on peak shear rates and flow distribution 22,23; models of specific hemodialysis cannulae have been used to validate hemolysis calculations 24 and study flow fields in a more complicated cannula design 25; a study on a new design for a cardiopulmonary bypass cannula predicted higher flow rates and exit velocities compared with a control cannula 26; and, in a new design for an artificial lung access cannula 27, the influence of the novel geometry on shear stress distribution and hemolysis production was assessed 28.…”