What is included in pulmonary function testing for lung surgery assessment?

Updated: May 14, 2020
  • Author: Kevin McCarthy, RPFT; Chief Editor: Nader Kamangar, MD, FACP, FCCP, FCCM  more...
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Answer

Answer

Assessment for lung surgery typically involves prediction of a postoperative FEV1 by using the preoperative FEV1. In a borderline case, consideration of the contribution of the remaining portions can be assessed by a perfusion scan. The relative percentage of perfusion (Q) of the remaining lung or lung segments usually is proportional to its contribution to ventilation and can be used to estimate postoperative function as shown in the following equation:

Postoperative FEV1 = Preoperative FEV1 × Q% of the remaining lung

For example, if the preoperative FEV1 is 1.6 L and the lung to be resected demonstrates 40% perfusion, the postoperative FEV1 would be 1.6 × 0.6 = 0.96 L. An estimated postoperative FEV1 of less than 0.8 L often is associated with chronic respiratory failure and may indicate an unacceptable degree of operative risk. Arterial blood gases (ABGs) and cardiopulmonary exercise testing may help evaluate operative risk in patients who have a preoperative FEV1 below 2 L or 50% of predicted.

The algorithm for clearance of candidates for lung resection proposed by Bolinger and Perruchoud [5] has been successfully evaluated in 137 consecutive patients who were referred for resection by Wyser et al [6] with an overall mortality of 1.5% and is detailed in Cardiopulmonary Stress Testing. Patients with a negative cardiac history and ECG that demonstrate an FEV1 and a diffusing capacity of lung for carbon monoxide (DLCO) that are greater than 80% of predicted are judged to be able to undergo pneumonectomy safely.


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