title: Core body temperature control by total liquid ventilation using a virtual lung temperature sensor.
abstract: In total liquid ventilation (TLV), the lungs are filled with a breathable liquid perfluorocarbon (PFC) while a liquid ventilator ensures proper gas exchange by renewal of a tidal volume of oxygenated and temperature-controlled PFC. Given the rapid changes in core body temperature generated by TLV using the lung has a heat exchanger, it is crucial to have accurate and reliable core body temperature monitoring and control. This study presents the design of a virtual lung temperature sensor to control core temperature. In the first step, the virtual sensor, using expired PFC to estimate lung temperature noninvasively, was validated both in vitro and in vivo. The virtual lung temperature was then used to rapidly and automatically control core temperature. Experimentations were performed using the Inolivent-5.0 liquid ventilator with a feedback controller to modulate inspired PFC temperature thereby controlling lung temperature. The in vivo experimental protocol was conducted on seven newborn lambs instrumented with temperature sensors at the femoral artery, pulmonary artery, oesophagus, right ear drum, and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with fast hypothermia induction, followed by slow posthypothermic rewarming for 1 h, then by fast rewarming to normothermia and finally a second fast hypothermia induction phase. Results showed that the virtual lung temperature was able to provide an accurate estimation of systemic arterial temperature. Results also demonstrate that TLV can precisely control core body temperature and can be favorably compared to extracorporeal circulation in terms of speed.
authors: Mathieu
authors: M
authors: Nadeau
authors: Philippe
authors: P
authors: Micheau
authors: Raymond
authors: R
authors: Robert
authors: Olivier
authors: O
authors: Avoine
authors: Renaud
authors: R
authors: Tissier
authors: Pamela Samanta
authors: PS
authors: Germim
authors: Jonathan
authors: J
authors: Vandamme
authors: Jean-Paul
authors: JP
authors: Praud
authors: Herve
authors: H
authors: Walti
mesh_terms: D000389:Air Conditioning / Q000295:instrumentation / Q000379:methods; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005246:Feedback; D025461:Feedback, Physiological / Q000502:physiology; D006361:Heating / Q000295:instrumentation / Q000379:methods; D021061:Liquid Ventilation / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012756:Sheep; D013813:Therapy, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D013817:Thermography / Q000295:instrumentation* / Q000379:methods*; D014584:User-Computer Interface