Measurement of diffusing capacity (DLCO)
One of the most clinically lung function test is diffusing capacity of the lung for carbon monoxide (DLCO). In addition it's known as the transfer factor of the lung for CO (TLCO). This test measures the capability of the lungs to transmit gas from inhaled air to the pulmonary capillaries in the red blood cells and to determine the efficiency of the lungs to exchange gases. The indication of using this test is to recognize the cause of hypoxemia and Dyspnea, identify pulmonary hypertension in patient at risk, to diagnosis of obstructive and restrictive disease, and to monitor the development of interstitial lung disease. There are no adverse effects or contraindication for this test. The DLCO is an …show more content…
This equation expresses the relationship between these values; DLCO= VCO/PASO where a volume of gas must be at standard temperature (0.0oC), 0.0% saturated with water vapor and pressure (760mm Hg). The three methods used to measuring DLCO and acquiring the two values are, single breath method (DLCO-SB), steady-state, and rebreathing method (DLCO-RB). Approximately a single- breath method is the mostly uses by all pulmonary function laboratories because it is quicker to perform than other techniques such as rebreathing technique. In the single-breath technique, a technologist will instruct you on how to perform the test and encourage you to do your best. In this test, the patient will seated, has a nose clip and mouthpiece in place. Firstly, the patient will instruct to exhales to residual volume (limited to 6 seconds) and then inspires the test gas mixture (10% helium, 0.3% CO, 21% oxygen, and balance nitrogen) rapidly to total lung capacity. After that the patient should try to hold the breath at total lung capacity level for a period of time approximately 10 seconds (9-11 seconds). Then the subject has to exhale quickly and completely as possible to return in the residual volume level (shouldn't go above 4 second). The better the diffusing capacity, the more carbon monoxide will be absorbed from a single 10 second holding. …show more content…
This may be as a result of lung diseases such as: pulmonary embolism, Asthma (slightly increased), pulmonary hypertension, interstitial fibrosis, and Emphysema. The loss of alveolar membrane surface area like in emphysema and Thickening of the alveolar-capillary membrane in interstitial lung disease are the main causes of a low DLCO. Vise versa the DLCO and the volume of blood in the pulmonary capillaries are increased in these conditions; when there is recruited in pulmonary capillaries, as occurs through exercise, when the patient is lying in the supine position, and when a left-to-right cardiac shunt is
One of the most clinically lung function test is diffusing capacity of the lung for carbon monoxide (DLCO). In addition it's known as the transfer factor of the lung for CO (TLCO). This test measures the capability of the lungs to transmit gas from inhaled air to the pulmonary capillaries in the red blood cells and to determine the efficiency of the lungs to exchange gases. The indication of using this test is to recognize the cause of hypoxemia and Dyspnea, identify pulmonary hypertension in patient at risk, to diagnosis of obstructive and restrictive disease, and to monitor the development of interstitial lung disease. There are no adverse effects or contraindication for this test. The DLCO is an …show more content…
This equation expresses the relationship between these values; DLCO= VCO/PASO where a volume of gas must be at standard temperature (0.0oC), 0.0% saturated with water vapor and pressure (760mm Hg). The three methods used to measuring DLCO and acquiring the two values are, single breath method (DLCO-SB), steady-state, and rebreathing method (DLCO-RB). Approximately a single- breath method is the mostly uses by all pulmonary function laboratories because it is quicker to perform than other techniques such as rebreathing technique. In the single-breath technique, a technologist will instruct you on how to perform the test and encourage you to do your best. In this test, the patient will seated, has a nose clip and mouthpiece in place. Firstly, the patient will instruct to exhales to residual volume (limited to 6 seconds) and then inspires the test gas mixture (10% helium, 0.3% CO, 21% oxygen, and balance nitrogen) rapidly to total lung capacity. After that the patient should try to hold the breath at total lung capacity level for a period of time approximately 10 seconds (9-11 seconds). Then the subject has to exhale quickly and completely as possible to return in the residual volume level (shouldn't go above 4 second). The better the diffusing capacity, the more carbon monoxide will be absorbed from a single 10 second holding. …show more content…
This may be as a result of lung diseases such as: pulmonary embolism, Asthma (slightly increased), pulmonary hypertension, interstitial fibrosis, and Emphysema. The loss of alveolar membrane surface area like in emphysema and Thickening of the alveolar-capillary membrane in interstitial lung disease are the main causes of a low DLCO. Vise versa the DLCO and the volume of blood in the pulmonary capillaries are increased in these conditions; when there is recruited in pulmonary capillaries, as occurs through exercise, when the patient is lying in the supine position, and when a left-to-right cardiac shunt is