What will be the effect on spirometry in case of lobectomy done for bronchogenic carcinoma?
## **Core Concept**
Lobectomy, the surgical removal of a lung lobe, is a treatment option for bronchogenic carcinoma. Spirometry is a common pulmonary function test that measures lung volumes and capacities, including forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). The impact of lobectomy on spirometry results depends on the lung's compensatory mechanisms and the extent of lung tissue removed.
## **Why the Correct Answer is Right**
The correct answer, , indicates a decrease in FEV1 and FVC. After a lobectomy, the total lung volume decreases because one lobe of the lung is removed. However, the lung's compensatory mechanisms, such as the diaphragm's increased movement and the rib cage's expansion, can partially offset this loss. FEV1, which measures the volume of air that can be forcibly exhaled in one second, and FVC, which measures the total volume of air that can be forcibly exhaled after maximal inspiration, both decrease. However, the ratio of FEV1 to FVC (FEV1/FVC) often remains normal or near-normal because both values decrease proportionally.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option would imply an increase in lung volumes, which is not possible after a lobectomy since lung tissue is being removed.
- **Option B:** This option suggests that only FVC decreases while FEV1 remains the same, which does not accurately reflect the proportional decrease in both parameters post-lobectomy.
- **Option D:** This option implies no change in spirometry results, which is incorrect given that removing lung tissue would necessarily decrease lung volumes and capacities.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while lobectomy does decrease lung function as measured by spirometry, the extent of the decrease can vary based on the patient's preoperative lung function, the lobe removed, and the presence of any underlying lung disease. Patients with better preoperative lung function tend to tolerate lobectomy better.
## **Correct Answer:** . Decrease in FEV1 and FVC.