Objective To improve the Heron’s technique for heterotopic cardiac transplantation in rats by cuff vessel anastomosis in some aspectsand successfully establish the simplified model of cervical cardiac xenotransplantation from guinea pigs donor to SD rats recipients. Methods The donors were 64 male guinea pigs, whose weight ranged from 250 to 350 g； the recipients were 64 male SD rats, whose weight ranged from 300 to 350 g.The guinea pigs donor’s ascending aorta and pulmonary artery were anastomosed to SD rats recipient’s right common carotid artery and external jugular vein respectively with a self-made “sleeve” anastomosis. The modified cuff technique of heterotopic grafting is described in detail. Results 64 consecutive successful transplantations have been performed by single surgeon were done with negligible operative risk. No anastomosis leakage nor vessel obstruction. The total time of surgical procedure were 45 to 60 minutes. The new technique allowed vascular anastomoses to be completed in 2 to 5 minutes. The total cold ischemia time for donor heart was 14 minutes in average. Conclusion This modified Heron’s technique was a simple, economical, practicable,reliable and high reproducible model can be operated by surgeons with minimal training in microvascular surgery, and be applied to various transplantation immunological studies.
Objective To analyze the risk factors for ventilator-associated pneumonia( VAP) in adult patients undergoing cardiac surgery with cardiopulmonary bypass ( CPB) . Methods A total of 127 consecutive adult patients who received postoperative ventilation for more than 48 hours between January 2002 and June 2008 in the cardiac surgical intensive care unit( CSICU) were included in this study. The patients were assigned into a VAPgroup( n =64) and a control group( n = 63) . Pre-, intra-, and postoperative factors were collected and analyzed between two groups, and the multivariate analysis( logistic regression)were used to identify the risk factors of VAP. Results The overall incidence of VAP was 5.1%. The mortality of VAP was 28. 1% . Compared to the control group, the patients in the VAP group had longer duration of cardiopulmonary bypass time, ventilation time, more blood products usage and the duration of stay in CSICU( P lt; 0. 001) , higher morbidity of low cardiac output syndrome and tracheotomy( P lt; 0. 01) and higher rate of aortic surgery and mortality( P lt; 0. 05) . The preoperative left ventricular ejection fraction ( LVEF) and postoperative oxygenation index( PaO2 /FiO2 ) were lower in the VAP group than those of the control group( P lt; 0. 001) . Five variables were found to be significantly related to the development of VAP by multivariate analysis: CPB time gt; 120 min( OR = 6. 352, P = 0. 000) ; PaO2 /FiO2 lt; 300 mm Hg( OR =3. 642, P = 0. 017) , transfusion of blood products ≥1500 mL( OR = 5. 083, P = 0. 039) , ventilation time≥5 days( OR = 9. 074, P = 0. 047) and tracheotomy( OR = 19. 899, P = 0. 021) . A total of 102 pathogens were obtained by sputum culture in 64 VAP patients. There were 62( 60. 8% ) cases of gram negative bacilli, 19 cases( 18. 6% ) of gram positive cocci and 21( 20. 6% ) cases of eumycetes. Conclusion This study shows that the cardiopulmonary bypass time, ventilation time, hypoxemia, blood products transfusion and tracheotomy are risk factors most likely associated with VAP development.