Background Commercially available near infrared spectroscopy devices for continuous free
flap tissue oxygenation (StO 2) monitoring can only be used on flaps with a cutaneous
component. Additionally, differences in skin quality and pigmentation may alter StO 2
measurements. Here, we present a novel implantable heat convection probe that measures
microvascular blood flow for peripheral monitoring of free flaps, and is not subject to the
same issues that limit the clinical utility of near-infrared spectroscopy. Methods The …

Purpose: Cutaneous devices employing near infrared spectroscopy (NIRS) for continuous
free flap tissue oxygenation (StO2) monitoring have several limitations. Confounding factors
like skin pigmentation and thickness, ambient light incursion, and inconsistency at the skin-
sensor interface can alter StO2 measurements. Additionally, commercially available NIRS
sensors can only be used on flaps with a cutaneous component. We present a novel thermal
diffusivity probe for measuring microvascular blood flow as an alternative means for …