University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

489

Pages:

2
Author:

Mariam A. A.

DLCO Concept Questions 1. a. b. c. Answer the following questions about DLCO What is the importance of DLCO (1 mark) Write the DLCO formula and explain what each part means (4 marks) How do each of the following affect DLCO i. Supplemental O2 (1.5 mark) ii. Haemorrhage (1.5 mark) iii. Exercise (1.5 mark) iv. Anaemia (1.5 mark) v. Smoking (1.5mark) d. Explain why KCO increases with smaller lung volumes. (2 marks) Answer: a. DLCO helps us determine extent of diffusion (diffusion of O2 into the capillary and CO2 into the alveoli). It also gives us an idea about surface area and membrane thickness b. DLCO formula c. Factors affecting DLCO i. Oxygen competes with CO for Hb, which may lead to kicking out CO, thus this will decrease DLCO, due to less CO being able to diffuse, because there will be lots of CO in the capillary blood, which will quickly reach equilibrium within CO in the alveolar ii. Haemorrhage -> decreases alveolar wall -> decrease thickness -> easy leakage of CO from alveolar into capillary blood -> increase DLCO iii. In exercise there is increased cardiac output -> increase blood delivery to the alveolar -> more RBCs -> more Hb for CO carrying. There is also increased vessel perfusion and thus increasing SA -> these factors lead to increased DLCO iv. In anaemia there is decreased number of functional RBCs -> decreased Hb -> decreased CO carrying -> decreased CO diffusion, as equilibrium between the alveolar and the capillary -> decreased CO diffusion from the alveolar to capillary -> decreased DLCO v. Smoking decrease DLCO because it has CO which competes with the test CO and also smoking damages the alveolar sacs -> decreases SA -> decrease DLCO d. KCO refers to the transfer co-efficient of CO. If the lung volume decreases for any reason, the cardiac output remains the same, as the heart is not affected. This means that lung is receiving more blood compared to its’ volume and its’ alveolar volume. This means each alveolar will be exposed to more blood hence more RBCs and Hbs and more binding sites for CO, so more CO will diffuse from the alveolar into the blood.