Prediction of postoperative pulmonary reserve in lung resection patients

We performed Ventilation/Perfusion scans for patients planned for thoracotomy with resection of the primary or metastatic lung tumors. We predicted the post-operative FEV1 (Forced Expiratory Volume in first second) using Differential Lung Analysis software.

34 patients were evaluated with Ventilation/Perfusion (V/Q) scans. Ventilation scan was performed with Tc-99m DTPA Aerosol and Perfusion Scan with Tc99m MAA, on 2 different days. The numbers of counts in anterior and posterior views of V/Q scans were calculated individually. Anterior and posterior arithmetical mean was calculated and post-operative FEV1 was predicted with the use of Differential Lung Analysis software. In most of the patients, the counts in the ventilation scan were lower and they were related to preoperative FEV1. Depending on the volume of lung resection, i.e. Upper, Middle and Lower zones or Total Pneumonectomy, FEV1 was calculated. Whenever FEV1 was >0.8 (L), the patient was taken up for resection (and if there were no other risk factors, such as cardiac complications, chronic obstructive pulmonary diseases, and any other pathological conditions involving the contralateral lung).

Most of the 34 patients were taken up for lung resection based on our FEV1 predictions. In 7 patients, repeat spirometry (i.e. pulmonary function test) was done at varying intervals after surgical procedures and the variation between preoperative FEV(1) and postoperative FEV(1) was only ±15%, at the most.

Postoperative FEV(1) based on V/Q scan and pulmonary function tests helped us to proceed with lung resection after assessment of the pulmonary reserve.