约翰霍普金斯大学-led research finds larger lungs associated with 30 percent increase in survival at one year

Transplant teams have long tried to match the size of donor lungs to the size of the recipient as closely as possible, concerned that lungs of the wrong size could lead to poor lung function and poor outcomes. But new 约翰霍普金斯大学-led research suggests that oversized donor lungs may instead be the best option for patients, finding they are associated with a 30 percent increased chance of survival one year after the operation.

The issue of lung size was brought into the spotlight recently with the case of a 10-year-old Pennsylvania girl in need of a lung transplant. Regulations have made children under the age of 12 ineligible to receive adult lungs, 主要是因为潜在的大小不匹配. Her situation sparked a national debate on organ allocation procedures, and her family successfully petitioned the courts to enable her to receive lungs from an adult.

“Despite what we thought, bigger lungs turn out to be better,” says 基督教的一个. 梅洛,米.D., M.P.H., a lung transplant expert at the 约翰霍普金斯大学 University 医学院 and senior author of a study published in the August issue of the The Annals of Thoracic Surgery. “肺移植的存活率, 不幸的是, are not as good as with other solid organ transplants like liver, 肾脏和心脏. But our study tells us that if we were to routinely transplant larger lungs into patients, 我们可能会对生存产生真正的影响. 这就是研究的目的.”

Lung size can be estimated from the height and sex of the patients and is termed the “predicted total lung capacity.” Taller people have bigger lungs and a man’s lungs are larger than a woman’s of the same height. The researchers defined lung size mismatch as the ratio of the predicted lung capacity of the donor relative to the recipient. 例如，比率为1.0是一个完美的大小匹配，而比率为1.3 indicates that the transplanted lung is significantly larger than the predicted total lung capacity for the recipient. Merlo’s research found that double lung transplant recipients who received lungs with an average ratio of 1.其中3人在第一年死亡的可能性降低了30%.

这项研究由Michael Eberlein博士领导.D., Ph.D., 约翰·霍普金斯大学的前住院医生和研究员, 是通过分析4,520个双肺移植和2个,477 single lung transplants performed between May 2005 and April 2010 in the United States. The findings were clearer about the benefits of larger lungs in double lung transplants than in single ones, though oversized lungs did convey some survival benefit in those cases as well, 他们发现.

“Size is a more powerful predictor of survival than we ever thought,” says Ashish S. 沙,M.D., surgical director of lung transplantation at The 约翰霍普金斯大学 Hospital and another of the study’s authors. “对超大肺的恐惧似乎是没有根据的. 我们希望这项研究能消除一些误解.”

In lung transplant, the sickest patients move to the top of the list. 一旦一个成年推荐十大正规网赌平台在名单上, height and gender (along with blood type) are used to determine whether those lungs are suitable for that patient. Merlo and 沙阿 say it might be better to build in a calculation for predicted lung capacity. 这种方式, oversized lungs could be offered to patients instead of smaller lungs that may not work as well.

他们警告说，肺可能太大了. 如果肺超过了一定的大小, 外科医生可能很难关闭胸腔, the lungs could be too compressed and collapse or could weigh too heavily on the heart, 导致低血压和其他问题.

目前, children under 12 cannot receive adult lungs and adults cannot receive lungs from pediatric donors. 沙阿, 约翰霍普金斯大学的外科副教授, says the findings suggest that there may be some benefit to removing age from the equation altogether when allocating lungs, putting children and adult donors and recipients into the same pool. 然后, doctors could make decisions based on each individual case and the size of the donor organs that become available.

“This study tells us that rather than looking at things like age or height, you have to look at each patient very carefully and determine what their lung capacity is,沙阿说。. “There may be children who could take adult lungs that would be oversized for them with a good result. And there may be small adults who would do well with pediatric lungs.”

仍然, 沙阿指出, 而更大的肺可能是理想的, transplant candidates who don’t get new organs are more likely to die, 所以小一点的肺总比没有好. 目前有超过1个,600 people listed for lung transplants in the United States and many die before getting new lungs. One-year survival after lung transplantation is 80 percent.

The research was supported in part by the 健康 资源 and Services Administration (contract 234-2005-370011C).

Other 约翰霍普金斯大学 researchers contributing to the study include George Arnaoutakis, M.D.; Jonathan B. 奥伦,M.D.; and Roy G. 布劳尔,M.D.