plethysmography
Plethysmography is used to measure changes in volume in different parts of the body. This can help check blood. The test may be done to check for blood clots in the arms and legs, or to measure how much air you can hold in your lungs.
Lung plethysmography:
You will breathe or pant against a mouthpiece. Clips will be put on your nose to shut off your nostrils. Depending on the information your doctor is looking for, the mouthpiece may be open at first, and then closed.
You will be breathing against the mouthpiece in both the open and closed positions - they give different information to the doctors. As your chest moves while you breathe or pant, it changes the pressure and amount of air in the room and against the mouthpiece. From these changes, the doctor can get an accurate measure of the amount of air in your lungs.
Plethysmograph:
A plethysmograph is an instrument for measuring changes in volume within an organ or whole body (usually resulting from fluctuations in the amount of blood or air it contains).
Organs studied:
1) Lungs[edit]
Pulmonary plethysmographs are commonly used to measure the functional residual capacity
(FRC) of the lungs—the volume in the lungs when the muscles of respiration are relaxed—and total lung capacity.
In a traditional plethysmograph, the test subject is placed inside a sealed chamber the size of a small telephone booth with a single mouthpiece. At the end of normal expiration, the mouthpiece is closed. The patient is then asked to make an inspiratory effort. As the patient tries to inhale (a maneuver which looks and feels like panting), the lungs expand, decreasing pressure within the lungs and increasing lung volume. This, in turn, increases the pressure within the box since it is a closed system and the volume of the box compartment has decreased to accommodate the new volume of the subject.
Boyle's Law is used to calculate the unknown volume within the lungs. First, the change in volume of the chest
Lung plethysmography:
You will breathe or pant against a mouthpiece. Clips will be put on your nose to shut off your nostrils. Depending on the information your doctor is looking for, the mouthpiece may be open at first, and then closed.
You will be breathing against the mouthpiece in both the open and closed positions - they give different information to the doctors. As your chest moves while you breathe or pant, it changes the pressure and amount of air in the room and against the mouthpiece. From these changes, the doctor can get an accurate measure of the amount of air in your lungs.
Plethysmograph:
A plethysmograph is an instrument for measuring changes in volume within an organ or whole body (usually resulting from fluctuations in the amount of blood or air it contains).
Organs studied:
1) Lungs[edit]
Pulmonary plethysmographs are commonly used to measure the functional residual capacity
(FRC) of the lungs—the volume in the lungs when the muscles of respiration are relaxed—and total lung capacity.
In a traditional plethysmograph, the test subject is placed inside a sealed chamber the size of a small telephone booth with a single mouthpiece. At the end of normal expiration, the mouthpiece is closed. The patient is then asked to make an inspiratory effort. As the patient tries to inhale (a maneuver which looks and feels like panting), the lungs expand, decreasing pressure within the lungs and increasing lung volume. This, in turn, increases the pressure within the box since it is a closed system and the volume of the box compartment has decreased to accommodate the new volume of the subject.
Boyle's Law is used to calculate the unknown volume within the lungs. First, the change in volume of the chest