Apparatus and method for measuring extravascular lung water

Apparatus for providing a measure of extravascular lung water of a subject including means for providing an injection of a thermal indicator into the bloodstream of the subject at a position proximal to or in the right heart, including

• means for detecting the time-temperature concentration curve of the bloodstream at a position in a systemic artery,
• first means responsive to the time-temperature concentration curve detected in the systemic artery for calculating a characteristic time for the time-temperature curve,
• second means responsive to the time-temperature concentration curve detected in the systemic artery for calculating the cardiac output in accordance with the reciprocal of the area under the time-temperature curve, and
• means for calculating a measure of extravascular lung water including the product of the cardiac output times the characteristic time.

Apparatus for providing a measure of extravascular lung water of a subject using a single thermal indicator, including

• means for providing an injection of the thermal indicator into the bloodstream of the subject at a position proximal to or in the right heart,
• means for detecting a first temperature dilution curve of the bloodstream at a position in the pulmonary artery,
• means responsive to the first temperature dilution curve detected in the pulmonary artery for calculating a characteristic time for the first temperature dilution curve,
• means for detecting a second temperature dilution curve of the bloodstream at a position in a systemic artery, p1 means responsive to the second temperature dilution curve detected in the systemic artery for calculating a characteristic time for the second temperature dilution curve,
• means responsive to a temperature dilution curve of the bloodstream for calculating the flow of blood through the heart and lungs, in accordance with characteristics of the temperature dilution curve, and
• means for calculating a measure of extravascular lung water in accordance with the difference between the product of the flow times the characteristic time for the first temperature dilution curve and the product of the flow times the characteristic time for the second temperature dilution curve.

A method of measuring the extravascular lung water of a subject using a single thermal indicator, including the following steps

• providing an injection of the thermal indicator into the bloodstream of the subject at a position proximal to or in the right heart,
• detecting a first time-temperature concentration curve of the blood stream at a position in the pulmonary artery,
• calculating a characteristic time for the first time-temperature concentration curve,
• detecting a second time-temperature concentration curve of the bloodstream at a position in a systemic artery,
• calculating a characteristic time for the second time-temperature concentration curve,
• providing a calculation for the flow of blood through the heart and lungs, and
• calculating a measure of extravascular lung water in accordance with the product of the blood flow times the difference between the characteristic times for the first and second time-temperature concentration curves.

A method for measuring the extravascular lung water of a subject using a single thermal indicator and with the measure of extravascular lung water calculated from the product of the cardiac output times the difference between characteristic times determined from thermal dilution curves detected in systemic and pulmonary arteries, and with the method including the following steps

• providing a first catheter having an opening for injecting the thermal indicator and including a temperature sensitive device,
• providing a second catheter including a temperature sensitive device,
• inserting the first catheter through the right heart and into the pulmonary artery,
• inserting the second catheter into a systemic artery,
• injecting the thermal indicator proximal to or in the right heart,
• detecting the temperature dilution curve of the bloodstream within the pulmonary artery, and
• detecting the temperature dilution curve of the bloodstream within the systemic artery.

A method for measuring the extravascular lung water of a subject wherein an injection of a thermal indicator is provided into the bloodstream of the subject at a position proximal to or in the right heart, including the following steps

• detecting the time-temperature concentration curve of the bloodstream at a position in a systemic artery,
• calculating a characteristic time for the time-temperature curve,
• calculating the cardiac output in accordance with the characteristics of the time-temperature curve, and
• calculating the measure of extravascular lung water including the product of the cardiac output times the characteristic time.

A method for measuring the extravascular lung water of a subject using a single thermal indicator, including

• injecting the thermal indicator into the bloodstream of the subject at a position proximal to or in the right heart,
• detecting a first temperature dilution curve of the bloodstream at a position in the pulmonary artery,
• calculating a characteristic time for the first temperature dilution curve,
• detecting a second temperature dilution curve of the bloodstream at a position in a systemic artery,
• calculating a characteristic time for the second temperature dilution curve,
• calculating the flow of blood through the heart and lungs in accordance with characteristics of a temperature dilution curve, and
• calculating a measure of extravascular lung water in accordance with the difference between the product of the blood flow times the characteristic time for the first curve and the product of the blood flow times the characteristic time for the second curve.