Abstract: An apparatus for monitoring whether or not a distal end of a tube is positioned inside a blood vessel includes a heating element configured to heat the tube distal end, and a sensor arrangement configured to generate a measurement signal indicative for heat transferred by exterior of the distal end. The apparatus further includes a comparator configured to compare the measurement signal with a reference level. The reference level equals a value attained by the measurement signal in response to a minimum flow velocity in the blood vessel. Further, a system is configured to exchange a liquid with a mammal via a blood vessel. The system includes the apparatus having the tube.

Abstract: The invention relates to an apparatus (102) capable of accurately monitoring whether or not a distal end of a tube is positioned inside a blood vessel. The apparatus comprises a heating element (106) configured for heating the distal end and a sensor arrangement (110) for generating a measurement signal (114) indicative for heat transferred by an exterior of the distal end. For the purpose of comparing the measurement signal (114) with a reference level, the apparatus furthermore comprises a comparator arrangement (116). Herein the reference level equals a value attained by the measurement signal (114) in response to a minimum flow velocity in the blood vessel. The invention furthermore relates to a system (102) for exchanging a liquid with a mammal via a blood vessel. The system comprises a tube provided with the apparatus according to the invention.