Thermal disinfection system for a medical apparatus
A thermal disinfection system and a method to perform a thermal disinfection procedure of fluid lines of a medical apparatus are disclosed herein. In an example, the thermal disinfection procedure comprises at least the steps of receiving a temperature signal from a temperature sensor, determining a measured temperature value of a fluid within a hydraulic circuit, receiving a pressure signal from a pressure sensor, determining a measured local atmospheric pressure value, and driving a heating unit to heat the fluid based on the measured temperature value and the measured local atmospheric pressure value.
1 . A thermal disinfection system including a blood treatment apparatus comprising a hydraulic circuit for fluid transit, the hydraulic circuit including:
a dialysis supply line extending from a fluid inlet to a dialysis fluid supply outlet connectable to an inlet of a dialyzer;
a dialysis effluent line extending from a dialysate fluid return inlet to a drain exit, the dialysate fluid return inlet being configured to connect to an outlet of the dialyzer;
a heating unit configured to heat a fluid within the hydraulic circuit;
at least one temperature sensor configured to provide a signal representative of a fluid temperature within the hydraulic circuit; and
a pressure sensor configured to provide a signal representative of a local atmospheric pressure at a physical location of the thermal disinfection system,
wherein the blood treatment apparatus includes a control unit configured to perform a thermal disinfection procedure of the hydraulic circuit by:
receiving the signal representative of the fluid temperature from the at least one temperature sensor and determining a measured temperature value of the fluid within the hydraulic circuit,
receiving the signal representative of the local atmospheric pressure from the pressure sensor and determining a measured local atmospheric pressure value, and
driving the heating unit to heat the fluid based on the measured temperature value and the measured local atmospheric pressure value,
wherein the measured local atmospheric pressure value is related to a set temperature of the fluid by a predefined relationship that defines a boiling point temperature (“BPT”) as a function of the measured local atmospheric pressure value,
wherein 0.9·BPT<T fluid_set <0.99·BPT.
2 . The thermal disinfection system of claim 1 , wherein the control unit, when driving the heating unit to heat the fluid based on the measured temperature value and the measured local atmospheric pressure value, is configured to:
determine the set temperature of the fluid based on the measured local atmospheric pressure value, the set temperature including a temperature between 50° C. and 105° C.; and
control the heating unit, based on the measured temperature value, to heat the fluid up to, and not beyond, the set temperature,
wherein the control unit is configured to maximize the set temperature based on the measured local atmospheric pressure value to avoid boiling of the fluid within the hydraulic circuit.
3 . The thermal disinfection system of claim 2 , wherein the control unit is further configured to either:
update the measured local atmospheric pressure value after receiving subsequent pressure signals from the pressure sensor during the thermal disinfection procedure continuously, periodically, or randomly according to a predetermined sample rate that is between 0.01 Hz and 1000 Hz, the control unit being further configured to update the set temperature during the thermal disinfection procedure based on an updated measured local atmospheric pressure value; or
measure the local atmospheric pressure using the pressure sensor at an initial stage of the thermal disinfection procedure or just before starting the thermal disinfection procedure, and set the set temperature at the initial stage of the thermal disinfection procedure according to the updated measured local atmospheric pressure, the set temperature being kept constant during the thermal disinfection procedure.
4 . The thermal disinfection system of claim 1 , wherein the control unit is further configured to:
receive a set disinfection dose representative of a required disinfection grade, wherein the set disinfection dose is a thermal disinfection dose value expressed in seconds;
calculate, during the thermal disinfection procedure, an achieved disinfection dose; and
compare the achieved disinfection dose to the set disinfection dose and, based on the comparison, discontinue the thermal disinfection procedure when the achieved disinfection dose equals or exceeds the set disinfection dose,
wherein the set disinfection dose includes a value between 500 and 1000 seconds.
5 . The thermal disinfection system of claim 4 , wherein the achieved disinfection dose is calculated based on a reference fluid temperature measured by the at least one temperature sensor at a location in the hydraulic circuit that consistently experiences substantially a lowest fluid temperature during the thermal disinfection procedure, the reference fluid temperature being, at each point in time, substantially the lowest fluid temperature within the hydraulic circuit, and
wherein the achieved disinfection dose is calculated as a function of elapsed time.
6 . The thermal disinfection system of claim 4 , wherein the achieved disinfection dose is calculated based on a predetermined z-value defining a relationship between the fluid temperature and a thermal disinfection procedure effectiveness, the z-value including a value between 5° C. and 30° C., and
wherein the z-value corresponds to an increase in fluid temperature required to reduce a D-value of a microorganism by about 90%, the D-value being a time required at a given temperature to kill about 90% of a population of the microorganism.
7 . The thermal disinfection system of claim 4 , wherein the achieved disinfection dose is calculated by the following disinfection dose formula:
A 0_achieved =Σ10 (T(t)-80)/z ·Δt
wherein z=10° C., Δt is a time interval in seconds between measurements by the at least one temperature sensor as controlled by the control unit, and T=Tref is a reference fluid temperature measured by the at least one temperature sensor within the time interval Δt.
8 . The thermal disinfection system of claim 7 , wherein the at least one temperature sensor comprises:
a low temperature sensor arranged upstream from the heating unit, the low temperature sensor being arranged close to an inlet of the heating unit on the dialysis supply line;
a return fluid temperature sensor arranged on the dialysis effluent line, the return fluid temperature sensor being arranged close to a drain exit downstream from a return fluid pump arranged on the dialysis effluent line, wherein the fluid flows from the inlet, through the dialysis supply line and the dialysis effluent line, and towards the drain exit; and
a high temperature sensor arranged downstream from the heating unit, the high temperature sensor being arranged close to an outlet of the heating unit on the dialysis supply line, wherein the high temperature sensor is configured to detect a fluid temperature value of the fluid, the control unit being configured to control the heating unit so that T fluid_mes =T fluid_set .
9 . The thermal disinfection system of claim 7 , wherein the set disinfection dose is equal to A 0_set , the control unit being configured to end the thermal disinfection procedure when A 0_achieved ≥A 0_set corresponding to a disinfection procedure time period, the control unit being further configured to store in a memory the time period relative to the thermal disinfection procedure, wherein the control unit is configured to determine a starting time of a subsequent thermal disinfection procedure based on a time period of a preceding thermal disinfection procedure.
10 . The thermal disinfection system of claim 4 , wherein the control unit is configured to receive a threshold temperature value and to determine if a measured temperature of a heated fluid equals or exceeds the threshold temperature value, wherein the control unit is configured to calculate the achieved disinfection dose after determining that the measured temperature of the heated fluid equals or exceeds the threshold temperature value, the measured temperature of the heated fluid being a fluid reference temperature, and
wherein the control unit is configured to compute the achieved disinfection dose based on time periods when the fluid measured temperature of the fluid exceeds the threshold temperature value.
11 . The thermal disinfection system of claim 1 , wherein the hydraulic circuit comprises a pump and a shunt tube connecting the dialysis fluid supply outlet to the dialysate fluid return inlet for bypassing the dialyzer, the control unit being further configured to activate, during the thermal disinfection procedure, the pump to flow a heated fluid within the hydraulic circuit.
12 . The thermal disinfection system of claim 11 , wherein, during the thermal disinfection procedure, the hydraulic circuit is configurable in a loop circuit for recirculation of the heated fluid, the loop circuit comprising:
the heating unit;
the pump;
the at least one temperature sensor;
a part of the dialysis supply line;
a part of the dialysis effluent line;
one or more valves located on the hydraulic circuit and commandable between an open and a closed position by the control unit to allow or prevent, respectively, fluid passage; and
one or more bypass lines fluidly connecting the dialysis supply line to the dialysis effluent line, and
wherein the control unit is further configured to define the loop circuit by actuating the one or more valves located on the hydraulic circuit to allow recirculation of the heated fluid.
13 . A thermal disinfection system including a water purification apparatus comprising a hydraulic circuit connectable to medical apparatus, the hydraulic circuit comprising:
an inlet port for receiving water from a water source;
a filtration unit comprising one or more water filters configured to remove impurities from the water at least during a treatment session performed by the medical apparatus;
a heating unit configured to heat the water within the hydraulic circuit;
a temperature sensor configured to provide a signal representative of a water temperature; and
a pressure sensor configured to provide a signal representative of a local atmospheric pressure at a physical location of the thermal disinfection system;
wherein the water purification apparatus includes a control unit configured to perform a thermal disinfection procedure of the hydraulic circuit by:
receiving the signal representative of the water temperature from the temperature sensor and determining a measured temperature value of the water within the hydraulic circuit,
receiving the signal representative of the local atmospheric pressure from the pressure sensor and determining a measured local atmospheric pressure value, and
driving the heating unit to heat the water based on the measured temperature value and the measured local atmospheric pressure value,
wherein the measured local atmospheric pressure value is related to a set temperature by a predefined relationship that defines a boiling point temperature (“BPT”) as a function of the measured local atmospheric pressure value,
wherein 0.9·BPT<T fluid_set <0.99·BPT.
14 . A thermal disinfection system including a peritoneal dialysis apparatus comprising a hydraulic circuit for fluid transit, the hydraulic circuit including:
a dialysis fluid supply line extending from a dialysis fluid inlet to a dialysis fluid supply outlet configured to directly or indirectly transfer fresh peritoneal dialysis fluid to a patient's catheter;
a dialysis effluent line extending from a spent peritoneal dialysis fluid inlet to a drain exit, the spent peritoneal dialysis fluid inlet being configured to directly or indirectly receive spent peritoneal dialysis fluid from the patient's catheter;
a heating unit configured to heat a fluid within the hydraulic circuit;
a temperature sensor configured to provide a signal representative of a fluid temperature within the hydraulic circuit; and
a pressure sensor configured to provide a signal representative of a local atmospheric pressure at a physical location of the thermal disinfection system,
wherein the peritoneal dialysis apparatus includes a control unit configured to perform a thermal disinfection procedure of the hydraulic circuit by:
receiving the signal representative of the fluid temperature from the temperature sensor and determining a measured temperature value of the fluid within the hydraulic circuit,
receiving the signal representative of the local atmospheric pressure from the pressure sensor and determining a measured local atmospheric pressure value, and
driving the heating unit to heat the fluid based on the measured temperature value and the measured local atmospheric pressure value,
wherein the measured local atmospheric pressure value is related to a set temperature by a predefined relationship that defines a boiling point temperature (“BPT”) as a function of the measured local atmospheric pressure value,
wherein 0.9·BPT<T fluid_set <0.99·BPT.
15 . A thermal disinfection system including a blood treatment apparatus comprising a hydraulic circuit for fluid transit, the hydraulic circuit including:
a dialysis supply line extending from a fluid inlet to a dialysis fluid supply outlet connectable to an inlet of a dialyzer;
a dialysis effluent line extending from a dialysate fluid return inlet to a drain exit, the dialysate fluid return inlet being configured to connect to an outlet of the dialyzer;
a heating unit configured to heat a fluid within the hydraulic circuit;
a temperature sensor configured to provide a signal representative of a fluid temperature within the hydraulic circuit; and
a pressure sensor configured to provide a signal representative of a local atmospheric pressure at a physical location of the thermal disinfection system,
wherein the blood treatment apparatus includes a control unit configured to perform a thermal disinfection procedure of the hydraulic circuit by:
receiving the signal representative of the fluid temperature from the temperature sensor and determining a measured temperature value of the fluid within the hydraulic circuit,
receiving the signal representative of the local atmospheric pressure from the pressure sensor and determining a measured local atmospheric pressure value,
determining a set temperature of the fluid based on the measured local atmospheric pressure value to avoid boiling the fluid within the hydraulic circuit, the set temperature including a temperature between 70° C. and 105° C., based on the set temperature, calculating an estimated time to complete the thermal disinfection procedure,
comparing the estimated time to complete the thermal disinfection procedure to a reference time, and
based on the comparison, continuing with the thermal disinfection procedure or providing a recommendation to start a different disinfection procedure.
16 . The thermal disinfection system of claim 15 , wherein the measured local atmospheric pressure value is related to the set temperature by a predefined relationship that defines a boiling point temperature (“BPT”) as a function of the measured local atmospheric pressure value,
wherein 0.9·BPT<T fluid_set <0.99·BPT.
17 . The thermal disinfection system of claim 15 , wherein the control unit is configured to execute the different disinfection procedure that is a chemical disinfection that uses a chemical disinfection agent and requires less time for disinfection than the thermal disinfection procedure.
18 . The thermal disinfection system of claim 15 , wherein the blood treatment apparatus further comprises a user interface, wherein the control unit is further configured to:
provide on the user interface of the blood treatment apparatus an indication that the different disinfection procedure is recommended; and
enable a user to accept or reject performing the different disinfection procedure.
19 . A thermal disinfection system including a blood treatment apparatus comprising a hydraulic circuit for fluid transit, the hydraulic circuit including:
a dialysis supply line extending from a fluid inlet to a dialysis fluid supply outlet connectable to an inlet of a dialyzer;
a dialysis effluent line extending from a dialysate fluid return inlet to a drain exit, the dialysate fluid return inlet being configured to connect to an outlet of the dialyzer;
a heating unit configured to heat a fluid within the hydraulic circuit;
a temperature sensor configured to provide a signal representative of a fluid temperature within the hydraulic circuit; and
a pressure sensor configured to provide a signal representative of a local atmospheric pressure at a physical location of the thermal disinfection system,
wherein the blood treatment apparatus includes a control unit configured to perform a thermal disinfection procedure of the hydraulic circuit by:
receiving the signal representative of the fluid temperature from the temperature sensor and determining a measured temperature value of the fluid within the hydraulic circuit,
receiving the signal representative of the local atmospheric pressure from the pressure sensor and determining a measured local atmospheric pressure value Patm,
determining a set temperature of the fluid based on the measured local atmospheric pressure value Patm to avoid boiling the fluid within the hydraulic circuit, the set temperature including a temperature between 70° C. and 105° C.,
driving the heating unit to heat the fluid to the set temperature,
receiving a set disinfection dose representative of a required disinfection grade,
receiving a threshold temperature value,
calculating, during the thermal disinfection procedure, an achieved disinfection dose based on an elapsed time and a reference fluid temperature measured by the temperature sensor, the reference fluid temperature being substantially a lowest fluid temperature within the hydraulic circuit during the thermal disinfection procedure, wherein calculation of the achieved disinfection dose starts when a reference temperature of the heated fluid equals or exceeds the threshold temperature value, and
comparing the achieved disinfection dose to the set disinfection dose and, based on the comparison, discontinuing the disinfection procedure when the achieved disinfection dose equals or exceeds the set disinfection dose.
20 . The thermal disinfection system of claim 19 , wherein the the signal representative of the local atmospheric pressure is related to the set temperature by a predefined relationship that defines a boiling point temperature (“BPT”) as a function of the measured local atmospheric pressure value, wherein 0.9·BPT<T_(fluid_set)<0.96·BPT.
21 . The thermal disinfection system of claim 19 , wherein the control unit is configured to compute the achieved disinfection dose based on time periods when the measured temperature of the fluid exceeds the threshold temperature value.
22 . The thermal disinfection system of claim 19 , wherein the control unit is further configured to update the measured local atmospheric pressure value during the thermal disinfection procedure continuously, during a time period of the disinfection procedure, wherein the control unit is configured to update the measured local atmospheric pressure value according to a predetermined sample rate included between 0.1 Hz and 500 Hz.
23 . The thermal disinfection system of claim 22 , wherein the control unit is further configured to update the set temperature during the disinfection procedure based on updated measured local atmospheric pressure values.
24 . A thermal disinfection system including a blood treatment apparatus comprising a hydraulic circuit for fluid transit, the hydraulic circuit including:
a dialysis supply line extending from a fluid inlet to a dialysis fluid supply outlet connectable to an inlet of a dialyzer;
a dialysis effluent line extending from a dialysate fluid return inlet to a drain exit, the dialysate fluid return inlet being configured to connect to an outlet of the dialyzer;
a heating unit configured to heat a fluid within the hydraulic circuit;
a temperature sensor configured to provide a signal representative of a fluid temperature within the hydraulic circuit; and
a pressure sensor configured to provide a signal representative of a local atmospheric pressure at a physical location of the thermal disinfection system,
wherein the blood treatment apparatus includes a control unit configured to perform a thermal disinfection procedure of the hydraulic circuit by:
receiving the signal representative of the fluid temperature from the temperature sensor and determining a measured temperature value of the fluid within the hydraulic circuit,
receiving the signal representative of the local atmospheric pressure from the pressure sensor and determining a measured local atmospheric pressure value, and
driving the heating unit to heat the fluid based on the measured temperature value and the measured local atmospheric pressure value,
wherein the control unit is further configured to either:
update the measured local atmospheric pressure value after receiving subsequent pressure signals from the pressure sensor during the thermal disinfection procedure continuously, periodically, or randomly according to a predetermined sample rate that is between 0.01 Hz and 1000 Hz, the control unit being further configured to update a set temperature during the thermal disinfection procedure based on the updated measured local atmospheric pressure value; or
measure the local atmospheric pressure using the pressure sensor at an initial stage of the thermal disinfection procedure or just before starting the thermal disinfection procedure, and set the set temperature at the initial stage of the thermal disinfection procedure according to the measured local atmospheric pressure, the set temperature being kept constant during the thermal disinfection procedure.
25 . A thermal disinfection system including a blood treatment apparatus comprising a hydraulic circuit for fluid transit, the hydraulic circuit including:
a dialysis supply line extending from a fluid inlet to a dialysis fluid supply outlet connectable to an inlet of a dialyzer;
a dialysis effluent line extending from a dialysate fluid return inlet to a drain exit, the dialysate fluid return inlet being configured to connect to an outlet of the dialyzer;
a heating unit configured to heat a fluid within the hydraulic circuit;
a temperature sensor configured to provide a signal representative of a fluid temperature within the hydraulic circuit; and
a pressure sensor configured to provide a signal representative of a local atmospheric pressure at a physical location of the thermal disinfection system,
wherein the blood treatment apparatus includes a control unit configured to perform a thermal disinfection procedure of the hydraulic circuit by:
receiving the signal representative of the fluid temperature from the temperature sensor and determining a measured temperature value of the fluid within the hydraulic circuit,
receiving the signal representative of the local atmospheric pressure from the pressure sensor and determining a measured local atmospheric pressure value, and
driving the heating unit to heat the fluid based on the measured temperature value and the measured local atmospheric pressure value,
wherein the control unit is further configured to:
receive a set disinfection dose representative of a required disinfection grade, wherein the set disinfection dose is a thermal disinfection dose value expressed in seconds;
calculate, during the thermal disinfection procedure, an achieved disinfection dose; and
compare the achieved disinfection dose to the set disinfection dose and, based on the comparison, discontinue the thermal disinfection procedure when the achieved disinfection dose equals or exceeds the set disinfection dose,
wherein the set disinfection dose includes a value between 500 and 1000 seconds.