Wireless medical monitoring system

An electrocardiogram (ECG) monitor subunit employed in association with a patient companion assembly (PCA) in wireless communication with at least one medical monitor unit, said ECG monitor subunit comprising a processor processing ECG data received from the PCA,

• said ECG data including one or more measurements for each ECG lead,
• said ECG monitor subunit being operative:
• to provide said ECG data to a digital to analogue (D/A) converter, said D/A converter providing an analog date output,
• to filter the analog data output using a low pass filter, said low pass filter providing a low pass filter output signal, and
• to attenuate said low pass filter output signal thereby adapting said low pass filter output signal to a desired intensity level acceptable for input to the at least one medical monitor unit.

An electrocardiogram (ECG) subunit employed in a patient companion assembly (PCA) wirelessly communicating with at least one medical monitor unit, said ECG subunit processing input arriving from at least two ECG leads, said ECG subunit comprising:

• a medical sensor interface subunit having at least two ECG channel routes, each of said at least two ECG channel routes incorporating an ECG channel interface;
• an analogue to digital converter;
• a multiplexer for multiplexing output signals from said at least two ECG channel routes to said analogue to digital converter;
• a digital wireless communications subsystem (WSS) wirelessly communicating with a monitor wireless transceiver unit (MWT);
• and
• a processor for adapting a digital output from said analogue to digital converter to digital wireless communications for supplying to said digital wireless communications subsystem,
• said multiplexer multiplexing said output signals in at least two different sequences to compensate for a phase shift between said at least two ECG channel routes.

An emulator of a medical thermistor for use in a wireless transceiver unit connected to at least one medical monitor unit, said at least one medical monitor unit having at least one temperature socket, said emulator being a programmable device having a digital potentiometer working as a ratiometric divider, said emulator determining a function between entrance voltage and entrance current according to a resistance ratio between R3 and R2 as given by the equation:

• Vin=Iin(R1(R3/R2))
• where Vin is a voltage across an input of said emulator of a medical thermistor,
• R1 is a precision resistor determining thermistor emulation accuracy, and
• R3/R2 is a digital potentiometer ratio used in a divider mode defining a multiplication coefficient (R3/R2) and thereby determining a variable thermistor resistance value.

A wireless medical monitor comprising:

• a wireless monitor transceiver unit;
• and
• a medical monitor unit,
• said wireless monitor transceiver unit including a plurality of subunits selected from an ECG subunit, a SpO2 subunit, a temperature subunit, a pressure subunit, a respiratory subunit and a blood chemistry sub unit,
• each said plurality of subunits sharing, with at least one other of said plurality of subunits, at least one of a wireless communication subsystem, a processor, a digital to analogue (D/A) converter, an analogue to digital (A/D) converter, an opto-coupler, a power supply and a multiplexer.