The effect of pentoxifylline on the lung during cardiopulmonary bypass

Cardiopulmonary bypass (CPB) produces an inflammatory response due tothe interaction of blood with a foreign body surface. The lungs are mostaffected by this inflammatory response. Pentoxifylline (PTX), aphosphodiesterase inhibitor and an inhibitor of leukocyte activation, isused to minimize damage in lungs where leukocytes play an important role.Twenty patients with mitral valve stenosis with planned mitral valvesurgery were included in the study. The ten patients receivingpentoxifylline (PTX group) were administered 400 mg PTX orally TID for 3days preoperatively and, following anesthetic induction, a 300 mg PTXinfusion was given. The ten patients receiving no PTX were the controlgroup (CT). Platelet and leukocyte counts, mean pulmonary arterial pressure(mPAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI),pulmonary vascular resistance (PVR), alveolar-arterial PO2 gradient (AaDO2)were measured just before and after CPB, and 2 h postoperatively. Thenumber of the leukocytes increased in the blood samples drawn 15 min afterCPB in both groups and 2 h postoperatively showed no statistical change.The number of platelets had decreased significantly at the end of the CPBin both groups and, 2 h postoperatively, there was a further decrease inthe blood count in the control group (P < 0.05). There was nosignificant difference in either the preoperative or postoperative PAP,PAWP, and CI. Pulmonary vascular resistance increased in both groupsfollowing the CPB (CT, before: 136 +/- 44, after: 177 +/- 94 dyne.sec.cm-5; PTX, before: 151 +/- 82, after 182 +/- 43 dynes.sec.cm-5). Twohours postoperatively, a considerable increase continued in the controlgroup (CT 219 +/- 170 dynes.sec. cm-5), while there was an insignificantincrease in the PTX group (PTX 193 +/- 51 dynes.sec.cm-5) (P < 0.05).The alveolar-arterial PO2 gradient increased after the CPB in both groupsbut a moderate decrease was observed 2 h postoperatively. In lung biopsyspecimens taken before and after the CPB, there was marked leukocytesequestration in the control group, whereas the number of leukocytes wasseen to be insignificant in the PTX group (P < 0.005). This dosageregimen of PTX inhibits the postoperative increase in PVR and greatlyminimized leukocyte sequestration in the lung due to CPB.