Method and apparatus for zeroing and calibrating an invasive blood pressure monitoring system

A transducer support structure for providing protective support for the transducer and other apparatus of an invasive type blood pressure monitoring system incorporating a calibration chamber and bacteria filter, said support structure comprising:

• a transducer support body adapted for positionable interconnection with the upright pole of an I.V. stand;
• leveling means being interconnected with said transducer support body and adapted to be positioned for substantial contact with a point defining the mid-thoracic line of the patient, said leveling means defining a level reference;
• insert receiver means being provided on said transducer support body;
• transducer support insert means being receivable by said insert receiver means, said transducer support insert means defining at least one protective receptacle for a blood pressure monitoring transducer of a particular design;
• and
• a calibration chamber support being interconnected with said transducer support and adapted to position and securely hold a bacteria filter and a calibration chamber with the liquid level mark of the calibration chamber in level registry with said level reference.

Apparatus for zeroing and calibrating an invasive cardiovascular hemodynamic monitoring system, said apparatus including:

• a calibration chamber interconnected with a bacteria filter, said bacteria filter ensuring that no bacteria or other contaminants are allowed to pass into the calibration chamber from the external environment during the process of zeroing and calibrating the blood pressure monitoring system, thereby protecting the cardiovascular system of the patient from bacterial contamination from the blood pressure monitoring system;
• a selector valve having a first connector assembled to the pressure receiver inlet connector of a blood pressure transducer, a second connector interconnected with a cannula tube located in the patient's cardiovascular system and a third connector being interconnected with said calibration chamber, said selector valve being positionable at a monitoring position communicating the blood pressure of the patient to the diaphragm chamber of the blood pressure transducer and blocking communication between the patient and said calibration chamber, said valve being positionable at a calibration position communicating said calibration chamber with said diaphragm chamber and blocking communication between the patient and both said calibration chamber and said diaphragm chamber, the patient thus being protected by said valve against inadvertent injection of air emboli or loss of blood both during zeroing and calibration of the blood pressure monitoring system, said valve being positionable at a purging position communicating said calibration chamber with a source of sterile fluid for filling the calibration chamber to the proper level mark.

A method of zeroing and calibrating an invasive blood pressure monitoring system with a display device of which an oscilloscope waveform readout is typical and wherein said blood pressure monitoring system incorporates a calibration chamber and a plurality of blood pressure transducers each having a diaphragm chamber adapted for selective communication with a calibration chamber, said method comprising:

• purging air from said blood pressure monitoring system and filling the system with sterile fluid including filling the calibration chamber to a predetermined level;
• interconnecting the blood pressure transducers with the cardiovascular system of the patient through fluid filled tubing and a cannula inserted into the patient's cardiovascular system;
• locating the fluid-air interface in the calibration chamber at the level of the right atrium to the patient's heart;
• exposing the diaphragm of said transducer to zero reference pressure while maintaining the closed sterile integrity of said blood pressure monitoring system and setting the oscilloscope such that a read-out is indicated;
• applying a known desired pressure above the zero reference pressure to said diaphragm and inspecting proper calibration of the pressure monitoring system by inspecting the oscilloscope readout of said known pressure, said known desired pressure above the zero reference pressure being applied to said diaphragm while maintaining the closed sterile integrity of said blood pressure monitoring system;
• removing said known desired pressure above the zero reference pressure from said diaphragm after inspection of calibration of the pressure monitoring system is completed;
• and thereafter applying the cardiovascular pressure of the patient to said diaphragms by communicating said cannula with said diaphragms, thus causing said transducer to transmit an electrical waveform signal to said oscilloscope that is displayed on the screen of said oscilloscope.

Apparatus for zeroing and calibrating an invasive cardiovascular hemodynamic monitoring system, said apparatus including:

• a calibration chamber interconnected with a bacteria filter, said bacteria filter ensuring that no bacteria or other contaminants are allowed to pass into the calibration chamber from the external environment during the process of zeroing and calibrating the blood pressure monitoring system, thereby protecting the cardiovascular system of the patient from bacterial contamination from the blood pressure monitoring system;
• a plurality of selector valves having a first connector assembled to the pressure receiver inlet connector of a blood pressure transducer, a second connector interconnected with a cannula tube located in the patient's cardiovascular system and a third connector being interconnected with said calibration chamber, each said selector valves being positionable at a monitoring position communicating the blood pressure of the patient to the diaphragm chamber of the blood pressure transducer and blocking communication between the patient and said calibration chamber, said valves being positionable at a calibration position communicating said calibration chamber with said diaphragm chamber and blocking communication between the patient and both said calibration chamber and said diaphragm chamber, the patient thus being protected by said valve against inadvertent injection of air emboli or loss of blood both during zeroing and calibration of the blood pressure monitoring system, said valves being positionable at a purging position communicating said calibration chamber with a source of sterile fluid for filling the calibration chamber to the proper level mark, each said selector valve being independently positionable for monitoring, calibrating, and purging.