Effect of forced-air heaters on perfusion and temperature distribution during and after open-heart surgery

Abstract

Forced-air blankets reduce afterdrop. However, they do not lead to clinical relevant changes in deep thigh temperature. LDF measurements show that forced-air heating does not improve toe perfusion. The extra heat especially favours core temperature. This is underlined by the decrease in postoperative leg blood flow, suggesting that the majority of the warmed blood leaving the heart flows to core organs and not to the periphery.

Increased systolic blood pressure after mild cold and rewarming: relation to cold-induced thermogenesis and age

“…Nevertheless, other studies reported a persistent thermal gradient of approx. 3°C between muscle and skin tissue (Pennes 1948, Severens et al 2007. Given these previous observations, in combination with an observed 3.5°C drop in mean skin temperature in this study, it is plausible that peripheral muscle temperature dropped approx.…”

“…Human NST can be mediated by mitochondrial uncoupling in BAT and skeletal muscle (Astrup 1986, van Marken Lichtenbelt et al 2009, Wijers et al 2010. 3°C between muscle and skin tissue (Pennes 1948, Severens et al 2007. Indeed, age is associated with reduced amount of mitochondria in muscle cells (Conley et al 2007).…”

Thermal sensation: a mathematical model based on neurophysiology

“…However, during rewarming, the afterdrop in core temperature is clearly visible in the core warm thermoreception. An afterdrop in core temperature is caused by the return of cooled blood from the peripheral tissues (Severens et al., 2007). Although the range of the discharge rate change for core warm thermoreceptors is not as large as for skin warm thermoreceptors ( H warm : 3.4–3.5 pulse/s and P warm : 1.9–3.1 pulse/s), the associated weight (β) is considerably larger for core thermoreception than for skin thermoreception ( = −14.3 and = 2.3), which evens out the difference in discharge rate.…”

A model to predict patient temperature during cardiac surgery

“…During cardiac surgery a mixture of anesthetic drugs is administered to the patient. For the development of a vasoconstriction model, we used the anesthetic protocol of our prior measurement series (Severens et al 2007), with propofol as the main anesthetic agent. A linear relationship was derived between the anesthesia concentration and the vasoconstriction threshold.…”