Method and apparatus for detection of right to left shunting in the cardiopulmonary vasculature

Abstract

The present invention provides a rapid, economical test for the detection of a right to left shunt applicable to the population at large due to its safety and noninvasiveness. The intended procedure involves gaining access to the circulatory system, injecting a measurable substance, ideally during prolonged and/or repeated Valsalva maneuvers, and then rapidly and repeatedly, ideally continuously, assaying for the substance. Through the determination of the appearance of a small amount of the substance prior to the subsequent high concentrations generated by the remainder of the bolus, one may safely diagnose a meaningful communication between the right and left heart, or other right to left shunt bypassing the lungs.

1 . A method providing for the detection of cardiovascular shunting and/or bypassing of the pulmonary capillary bed comprising: 
 Intravascular injection of a measurable substance, and    Assaying for said measurable substance, and    Interpreting the appearance and/or disappearance of the measurable substance to determine if said shunting or bypassing is present    
   
   
       2 . The method of  claim 1  in which the measurable substance may be ethanol, indocyanine green, lithium, radiolabled plasma, ammonia or any other indicator capable of being injected and rapidly detected  
   
   
       3 . The method of  claim 1  in which said injection is accomplished by an automated mechanism to provide reliability of infusion  
   
   
       4 . The method of  claim 1  in which said assaying may be conducted repeatedly or on a continuous basis  
   
   
       5 . The method of  claim 4  in which the curve associated with said appearance of the substance is use to conduct said interpretation of the presence of shunting or bypassing  
   
   
       6 . The method of  claim 5  in which abnormal shape of the curve or appearance of measurable substance earlier than anticipated is interpreted as a the presence of shunting or bypassing  
   
   
       7 . The method of  claim 1  in which said assaying for said measurable substance occurs intravascularly  
   
   
       8 . The method of  claim 7  in which said intravascular measurement is accomplished at the site of injection of the measurable substance  
   
   
       9 . The method of  claim 8  in which a single multi-function catheter is used to inject the measurable substance and to assay for said measurable substance  
   
   
       10 . The method of  claim 1  in which said assaying for said measurable substance occurs external to the patient  
   
   
       11 . The method of  claim 1  in which injecting the measurable substance, assaying for said measurable substance and interpreting the acquired data may be fully automated  
   
   
       12 . A method providing for the detection of cardiovascular shunting and/or bypassing of the pulmonary capillary bed comprising: 
 Varying concentrations of inhaled oxygen, and    Measurement of blood oxygen content    
   
   
       13 . The method of  claim 12  in which inhaled oxygen and blood oxygen are used to directly measure cardiovascular shunting and/or bypassing of the pulmonary capillary bed  
   
   
       14 . The method of  claim 12  in which inhaled oxygen and blood gas measurements may be coordinated via a single instrument