Figure 2From: Pulmonary perfusion with oxygenated blood or custodiol HTK solution during cardiac surgery for postoperative pulmonary function in COPD patients: a trial protocol for the randomized, clinical, parallel group, assessor and data analyst blinded Pulmonary Protection Trial Classification of COPD. The limit is set out in international recommendations [15, 16]. COPD, chronic obstructive pulmonary disease.Back to article page