Page 49 - ANZCP Gazette MAY 2014

CAN DONATION AFTER CARDIAC DEATH ADDRESS
THE INCREASING DEMAND FOR DONOR HEARTS?
Mr Joshua Byrne MSc (Cardiovascular Perfusion) CCP, F.L. Rosenfeldt, R.F.Salamonsen, R. Ou, D.S. Esmore The Alfred, Commercial Rd, Melbourne, Victoria, 3004
Heart/Lung transplant recipients are traditionally transplanted with organs from a brain dead donor, where native circulation continues in the absence of any brain stem function. Globally, the demand for transplant organs has out grown supply, particularly in Australia which has some of the lowest donation rates in the world of 15.6 donors per million population. Increase in demand for organs, has led the medical profession to find a new avenue for organ donation. In the past decade, transplant centres have turned to donation after cardiac death (cessation of the native circulation) to address the organ supply/demand shortfall. Transplantation using DCD donor organs has been very successful in both renal and lung transplantation patients. Recently there has been a renewed interest in the possibility of cardiac transplantation from DCD donors. The question is can the DCD heart be re animated and successfully used in cardiac transplantation.
A canine model was used to examine the viability of DCD hearts in cardiac transplantation. Using a DCD protocol 12 dogs were euthanized, 4 were assigned to traditional cold storage preservation (4°C), 8 to continuous reinfusion of cold crystalloid myocardial preservation solution for a period of 4 hours. A further 12 dogs were euthanized and received the preserved DCD hearts. Myocardial function and metabolites were measured for a period of 4 hours post-transplant.
It was shown that DCD hearts that underwent continuous cold crystalloid preservation had superior right and left ventricular function post heart transplant when compared to traditional preservation methods.
CEREBRAL OXIMETRY: EVALUATION OF PERFUSION INTERVENTIONS DURING BYPASS
Jessica Ozdirik & Andrew Lahanas
Department of Clinical Perfusion, Prince of Wales Hospital, Level 3, Campus Building, Barker Street, Randwick, NSW 2031, Australia
Near-Infrared Spectroscopy (NIRS) is a non-invasive method frequently used for evaluating and optimising cerebral oxygenation during cardiac surgery. The regional oxygen saturation (rSO2%) within the microvasculature of the frontal cortex is an indication of the adequacy of perfusion to the brain and permits the Perfusionist to respond to desaturations with rapid interventions. Our objective was to evaluate the need for NIRS during routine coronary artery bypass graft (CABG) surgery by applying NIRS to 44 patients by collecting data during cardiopulmonary bypass (CPB), assessing the efficacy of specific interventions previously reported to augment rSO2%. There were 20 (45.5%) patients that required an intervention to be made in an attempt to raise their rSO2 above the minimum recommended threshold of 60%, 17 (85%) of which were successfully treated with at least one intervention. All interventions were found to have a positive
effect on cerebral oxygenation; however, there was no single intervention found to be superior to another, with an average increase in rSO2of 2%. Of the 17 patients successfully treated, an average of 2.5 interventions were required, demonstrating that multiple actions on perfusion parameters were necessary to return rSO2 levels within normal limits. When compared to the intervention-responders, the non-responders had a higher mean age (81 vs. 66 years, p = 0.019) and lower baseline rSO2 values (64% vs. 81%, p = 0.002), although the minimum rSO2 values on CPB were not significantly different. The non-responders displayed lower average baselines with a higher average age and lower preoperative haematocrit (HCT). In conclusion, the use of NIRS in routine CABGs has demonstrated to be beneficial in diagnosing perioperative cerebral desaturations, often requiring multiple interventions to treat successfully.
MAY 2014 | www.anzcp.org
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