Patent ID: 11957890
Assignee: GAMBRO LUNDIA AB
Field: Medical technology (Instruments)
Classification: CPC A  H | IPC A

Claim 0:
1. A medical device for introduction of a fluid into a blood circulation system of a patient, the medical device comprising:
at least one fluid circuit configured to be coupled to a vascular access of the patient to introduce the fluid into the patient, wherein the at least one fluid circuit comprises a heated portion; and
a warming unit coupled to the heated portion, the warming unit configured to warm the fluid before the fluid passes to the blood circulation system of the patient;
wherein the warming unit comprises:
at least one electrical heater element connected to a main electrical source providing a mains voltage,
at least one heat transfer element in contact with the heated portion,
an electrical safety insulation interposed between the at least one electrical heater element and the at least one heat transfer element,
a ground connection connected to the at least one heat transfer element, and
a leakage current reduction circuit operatively interposed between the at least one heat transfer element and the ground connection;

wherein the leakage current reduction circuit comprises:
a resistance element placed between the at least one heat transfer element and the ground connection, and
a current sense circuitry configured to sense a current through the ground connection;

wherein the leakage current reduction circuit is configured to:
monitor a current in the resistance element through the current sense circuitry, and when the monitored current is greater than a threshold current indicating that the patient is connected to the mains voltage, disconnect the ground connection from the at least one heat transfer element while keeping the at least one electrical heater element connected to the main electrical source to continue warming the fluid,
attempt to connect the ground connection to the at least one heat transfer element at a selected time interval after disconnecting the ground connection from the at least one heat transfer element while continuing to warm the fluid, and when the monitored current is lower than the threshold current, reconnect the ground connection to the at least one heat transfer element, and
return to monitoring the current in the resistance element through the current sense circuitry after reconnecting the ground connection to the at least one heat transfer element.