Mathematical, numerical and in-vitro investigation of cooling performance of an intra-carotid catheter for selective brain hypothermia

Abstract

Therapeutic hypothermia (TH) has become an established neuroprotective therapy for patients after cardiac arrest [1, 2]. Selective brain cooling represents a promising way to shorten the time to reach the target brain temperature and additionally spare other organs from damage caused by temperature decrease. We present the investigation of the cooling performance of a single-balloon catheter dimensioned for the placement within the common carotid artery (CCA) by means of three different approaches: mathematical, numerical and in-vitro testing.

Review of selective brain hypothermia in acute ischemic stroke therapy using an intracarotid, closed-loop cooling catheter

“…Mathematical models showed that while the balloon wall thickness plays a minor role, contributing to around 5% to 10% of heat exchange resistance, depending on balloon configuration. [6] In contrast, flow-dependent convective processes strongly influence the heat exchange processes. Numerical simulation, as well as in vitro test in a mock loop of intracarotid circulation with a blood substitute with different catheter designs, revealed a higher heat exchange for a higher number of shorter balloons, while keeping the exchange surface constant, which is attributable to boundary layer disruption and thus increase of convection.…”

“…[5] The increase of balloon diameter led to an improvement of heat exchange surface and at the same time influences convective exchange processes at both coolant and blood side. [6] Since the nonocclusive nature within the carotid artery is a main requisite, diameter was chosen in a size of around 4 mm, which causes a minor flow resistance according to fluid dynamical calculations.…”

Quantification of the temperature gradient through a catheter in continuous infusion thermodilution for coronary flow measurements

“…Theoretically, the temperature of a moving fluid in a catheter is governed by the convection-diffusion equation (Patankar 1980). Although some research has been carried out on numerically modelling the temperature inside a catheter (Meckel et al 2015, González-Suárez and Berjano 2016, there are no existing results on gaining insight into the temperature in a catheter using partial differential equations for the purpose of continuous infusion thermodilution, as far as the authors know. A few studies reported the results from in vitro and in vivo continuous thermodilution measurements in which the infusion rate was varied (Dumas and Barozzi 1984, Aarnoudse et al 2007, Van 't Veer et al 2016, Xaplanteris et al 2018.…”