Role of CO diffusing capacity during exercise in the preoperative evaluation for lung resection

Area of Science:

• Pulmonary Medicine
• Cardiopulmonary Physiology
• Surgical Risk Assessment

Background:

• Lung resection surgery carries significant postoperative risks.
• Assessing preoperative pulmonary function is crucial for predicting patient outcomes.
• Diffusing capacity for carbon monoxide (DL(CO)) is a key measure of gas exchange efficiency.

Purpose of the Study:

• To investigate the association between inadequate increase in DL(CO) during exercise and postoperative complications after lung resection.
• To identify DL(CO) response during exercise as a potential predictor of surgical risk.

Main Methods:

• Prospective study involving 57 patients undergoing lung resection.
• Utilized the three-equation method (3EQ-DL(CO)) to measure DL(CO) during exercise at 35% and 70% of maximal workload.
• Compared resting DL(CO), exercise-induced DL(CO) increase, and maximal oxygen uptake (VO(2)max) with postoperative complication rates.

Main Results:

• Patients with postoperative complications exhibited lower resting DL(CO) (R-DL(CO)), a smaller DL(CO) increase from rest to 70% maximal workload ([70% - R]-DL(CO)%), and lower VO(2)max.
• The [70% - R]-DL(CO)% was the strongest preoperative predictor of complications.
• A threshold of 10% for [70% - R]-DL(CO)% demonstrated high sensitivity (78%) and specificity (100%), identifying patients with a 100% complication rate if below this threshold.

Conclusions:

• An insufficient increase in DL(CO) during exercise ([70% - R]-DL(CO)% < 10%) is significantly associated with increased postoperative complications following lung resection.
• Preoperative assessment of exercise-induced DL(CO) response can aid in identifying high-risk patients for lung resection.