Monitoring system for cardiac surgical operations with cardiopulmonary bypass

Abstract

A monitoring system for cardiac operations with cardiopulmonary bypass comprising: a processor operatively connected to a heart-lung machine; a pump flow detecting device connected to a pump of the heart-lung machine to continuously measure the pump flow value and send it to the processor; a hematocrit reading device inserted inside the arterial or venous line of the heart-lung machine to continuously measure the blood hematocrit value and to send it to the processor; a data input device to allow the operator to manually input data regarding the arterial oxygen saturation and the arterial oxygen tension; computing means integrated in the processor to compute the oxygen delivery value on the basis of the measured pump flow, the measured hematocrit value, the preset value of arterial oxygen saturation, and the preset value of arterial oxygen tension; and a display connected to the processor to display in real-time the computed oxygen delivery value.

I claim: 
     
         1 . A method of continuously monitoring a patient's parameters in real-time during a surgical operation including cardiopulmonary bypass using a heart-lung machine having a controller, the method comprising:
 continuously detecting a pump flow rate value from a pump of the heart-lung machine during the surgical operation;   continuously detecting a hematocrit value of the patient during the surgical operation;   continuously obtaining an arterial oxygen saturation value of the patient during the surgical operation;   calculating in real-time during the surgical operation, with the controller, an indexed oxygen delivery value based on the continuous arterial oxygen saturation value of the patient, the continuous hematocrit value of the patient, and the continuous measure of the pump flow rate value; and   continually displaying in real-time on a display the calculated indexed oxygen delivery value calculated by the controller.   
     
     
         2 . The method of  claim 1 , further comprising:
 setting an indexed oxygen delivery threshold value;   continuously comparing the calculated indexed oxygen delivery value with the threshold value during the surgical operation; and   triggering an alarm in real-time if the calculated indexed oxygen delivery value breaches the threshold value.   
     
     
         3 . The method of  claim 2 , wherein the alarm is triggered when the calculated indexed oxygen delivery value falls below the threshold value. 
     
     
         4 . The method of  claim 2 , further comprising:
 showing the alarm in real-time on the display; and   displaying in real-time on the display during the surgical operation, the continuous measure of the pump flow rate value and the continuous measure of the hematocrit value.   
     
     
         5 . The method of  claim 2 , further comprising calculating in real-time an accumulated amount of time that the threshold value has been breached. 
     
     
         6 . The method of  claim 5 , wherein the alarm is not triggered when the accumulated amount of time is less than a time threshold. 
     
     
         7 . The method of  claim 6 , wherein the time threshold is 5 minutes. 
     
     
         8 . The method of  claim 5 , wherein the accumulated amount of time is a consecutive amount of time in a given time window. 
     
     
         9 . The method of  claim 5 , wherein the accumulated amount of time is a nonconsecutive amount of time in a given time window. 
     
     
         10 . The method of  claim 1 , further comprising continuously measuring and displaying the patient's body temperature. 
     
     
         11 . The method of  claim 10 , wherein setting the indexed oxygen delivery threshold value includes calculating the indexed oxygen delivery threshold value from the measured patient's body temperature. 
     
     
         12 . The method of  claim 1 , further comprising calculating in real-time during the surgical operation, with the controller, a hemoglobin value based on the continuous measure of the hematocrit value. 
     
     
         13 . The method of  claim 12 , wherein the display is configured to display a plurality of windows, wherein continually displaying includes displaying graphically the indexed oxygen delivery value as a function of time in a first window of the plurality of windows, the continuous measure of the pump flow rate in a second window of the plurality of windows, and displaying the hemoglobin value in a third window of the plurality of windows. 
     
     
         14 . The method of  claim 13 , wherein continually displaying further includes displaying at least one of the indexed oxygen delivery value, an elapsed time from start of cardiopulmonary bypass, a body surface area, and a body temperature, each in an additional individual window. 
     
     
         15 . The method of  claim 14 , wherein the first window is larger than the second window, the third window, and the additional individual widow. 
     
     
         16 . The method of  claim 1 , further comprising determining a body surface area of the patient, wherein calculating the indexed oxygen delivery value is further based on the body surface area of the patient. 
     
     
         17 . The method of  claim 1 , further comprising continuously detecting exhaled carbon dioxide at the heart-lung machine, providing a preset gas flow value, and calculating indexed carbon dioxide production based on the preset gas flow value and measured exhaled carbon dioxide. 
     
     
         18 . A method of continuously monitoring a patient's parameters in real-time during a surgical operation including cardiopulmonary bypass using a heart-lung machine having a controller, the method comprising:
 continuously detecting a pump flow rate from a pump of the heart-lung machine during the surgical operation;   continuously measuring and displaying the patient's body temperature;   continuously detecting a hematocrit value of the patient during the surgical operation;   continuously obtaining an arterial oxygen saturation value of the patient during the surgical operation;   calculating in real-time during the surgical operation, with the controller, an indexed oxygen delivery value based on the continuous arterial oxygen saturation value of the patient, the continuous hematocrit value of the patient, and the continuous measure of the pump flow rate value;   continually displaying in real-time on a display the calculated indexed oxygen delivery value calculated by the controller;   setting an indexed oxygen delivery threshold value by calculating the indexed oxygen delivery threshold value from the measured patient's body temperature;   continuously comparing the calculated indexed oxygen delivery value with the threshold value during the surgical operation; and   triggering an alarm in real-time if the calculated indexed oxygen delivery value breaches the threshold value.   
     
     
         19 . The method of  claim 18 , further comprising:
 showing the alarm in real-time on the display; and   displaying in real-time on the display during the surgical operation, the continuous measure of the pump flow rate value and the continuous measure.   
     
     
         20 . The method of  claim 19 , further comprising calculating in real-time an accumulated amount of time that the threshold value has been breached, wherein the alarm is not triggered when the accumulated amount of time is less than a time threshold.