[Perioperative lung injury in ventricular septal defect with severe pulmonary hypertension, a clinical study of 31 cases].

OBJECTIVE

To investigate the mechanism of perioperative lung injury in patients of ventricular septal defect (VSD) with severe pulmonary hypertension.

METHOD

The thromboxane B(2) (TXB(2)), 6-keto-prostagladin F(1 alpha) (6-keto-PGF(1 alpha)), malonyldiadehyde (MDA), interleukin-6 (IL-6), and IL-8, and blood pressure, pulmonary arterial pressure (PAP) and total pulmonary pressure (TPR) in thirty-one patients of VSD, 16 cases without pulmonary hypertension and 15 cases with severe pulmonary hypertension, were examined after anesthesia (AA), over extracorporeal circulation (OEC), and 1 hour (PEC1), 6 hours (PEC6), 24 hours (PEC24), 48 hours (PEC48), and 72 hours (PEC72) post extracorporeal circulation. The respiratory index (RI) and ratio of 6-keto-PGF(1alpha) and TXB(2) (P/T) were calculated. Before and after extracorporeal circulation, pulmonary tissues were taken to be examined by light microscopy and electron microscopy.

RESULT

In the cases with severe pulmonary hypertension the P/T was 0.81 +/- 0.26 after anesthesia, then decreased 0.65 +/- 0.28 over extracorporeal circulation, and reached its lowest value (0.51 +/- 0.32) 1 hour post extracorporeal circulation. MDA was 2.4 micromol/L +/- 0.6 micromol/L after anesthesia, then increased, was 7.0 micromol/L +/- 1.7 micromol/L OEC, and reached its peak value (7.3 micromol/L +/- 0.9 micromol/L) PEC1. IL-6 was 0.27 ng/L +/- 0.12 ng/L after anesthesia, then increased, and reached its peak value (0.50 ng/L +/- 0.19 ng/L) PEC1. IL-8 was 7.5 ng/L +/- 1.5 ng/L after anesthesia, then increased, was 152 ng/L +/- 50 ng/L PEC1, and reached its peak (183 ng/L +/- 63 ng/L) PEC6. TXB(2) was 251 ng/L +/- 44 ng/L after anesthesia, then increased, and reached its peak (967 ng/L +/- 145 ng/L) at PEC1. The PAP was 72.1 +/- 18.8 mm Hg after anesthesia, 55 mm Hg +/- 15.3 mm Hg OPC, and 7.4 +/- 2.1 at PEC1, then decreased, and was 53 mm Hg +/- 15 mm Hg at PEC72. The total pulmonary resistance (TPR) was 10.6 +/- 2.9 mm Hg x min(-1) x L(-1) after anesthesia, then increased, and reached its peak (15.0 +/- 3.9 mm Hg x min(-1) x L(-1) at PEC6. Respiratory index (RI) was 0.88 +/- 0.23, then increased, and reached its peak (2.35 +/- 0.72) at PEC6. TXB(2) and RI were positively correlated with pulmonary vascular resistance (gamma = 0.283, P < 0.05; gamma = 0.403, P < 0.05). RI was positively correlated with MDA (gamma = 0.403, P < 0.05). Morphologic studies revealed discontinuities in the endothelial cell lining of pulmonary capillaries, infiltration of inflammatory cells, plugging of pulmonary capillaries with neutrophils, and intraalveolar hemorrhage.

CONCLUSION

During the perioperative period, the pulmonary damage, which leads to pulmonary hypertensive crisis, is more severe among the cases of VSD with severe pulmonary hypertension than among the case without pulmonary hypertension.