NEW YORK (Reuters Health) – After brain death in potential lung donors, a “lung protective” strategy can increase the odds that the lungs will be viable for transplant, according to preliminary research released today by the Journal of the American Medical Association.
In the randomized controlled trial, the protective ventilation strategy nearly doubled the number of lungs eligible for transplant at 6 hours.
“We believe that results of this study will change guidelines for treatment of heart beating donors and will therefore change clinical practice worldwide,” Dr. V. Marco Ranieri of University of Turin in Italy noted in an e-mail to Reuters Health.
In an editorial, Dr. Mark S. Roberts of the University of Pittsburgh in Pennsylvania called the results “profound.”
The lung protective strategy, relative to the conventional strategy, includes maintaining lower tidal volumes (6-8 vs. 10-12 mL/kg of predicted body weight) and higher positive end-expiratory pressure (8-10 vs. 3-5 cm H2O); and using continuous positive airway pressure during apnea tests and closed circuit airway suction (as opposed to apnea tests performed by disconnecting the ventilator and open circuit airway suction).
Dr. Ranieri and colleagues compared the two strategies in a study conducted at 12 European intensive care units. Due to termination of funding, the trial was stopped after 118 donors were enrolled (59 in the conventional ventilation strategy and 59 in the protective ventilation strategy). The surgeons evaluating the organs for transplant suitability were blinded to the ventilation strategy.
After a six-hour observation period, 56 donors (95%) from the protective strategy group met lung donor eligibility criteria, compared with only 32 donors (54%) in the conventional strategy group (P < 0.001). Ultimately, lungs were harvested from 32 patients in the protective strategy group (54%) and from 16 (27%) in the conventional strategy group (P = 0.004). Donor eligibility at the end of six hours was associated with use of the protective strategy (odds ratio, 25.4) and with use of vasoactive drugs at randomization (odds ratio, 4.3). Although the numbers are small, there didn’t appear to be any harmful effect of the protective strategy on lung transplant outcomes. Twenty-four of the 32 patients (75%) who received lungs from donors in the protective strategy were alive at six months, compared to 11 of 16 patients (69%) who received lungs from donors in the conventional strategy group. The ventilation strategy also had no impact on the harvesting of other organs (hearts, livers and kidneys). Secondary analyses hint that the protective lung strategy may guard against inflammation. Dr. Ranieri and colleagues note in their report that currently, only 15% to 20% of lungs from donors with relatively normal lung function at the time of brain death maintain their suitability for transplantation. This may be partly due to an inadequate ventilation strategy used after brain death. In his editorial, Dr. Roberts calculates that adopting the lung protective strategy has the potential to double the number of lungs suitable for transplantation. This study, he writes, “provides sobering evidence that conventional lung preservation practices, which have been used for many years, are remarkably inefficient in their task and that improved lung preservation strategies can markedly increase the proportion of donated lungs that are transplanted.” He concludes, “This article should provide encouragement to continue to apply such rigorous methods to improve the viability of potential donor organs and to take better care of the gift of life.” JAMA 2010;304:26420-2627,2643-2644.
