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High Blood Ammonia Levels Are Associated with Poor Outcome after Lung Transplantation
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What is the problem and what is known about it so far?
Small amounts of ammonia are normally in the bloodstream. Many serious illnesses, including liver damage, can cause blood ammonia levels to rise. High levels of ammonia can cause patients to become confused and die, if left untreated. Massively increased ammonia levels have been found in a few patients after lung transplantation, but it is unknown how often this occurs or who will develop this condition. It has been demonstrated previously that two of these patients lacked a liver enzyme that helps to metabolize ammonia.
Why did the researchers do this particular study?
The researchers studied how often high blood ammonia levels occur in patients after lung transplantation. They also wanted to know which factors would help to identify those patients who will develop this potentially fatal complication.
Who was studied?
One hundred forty-five patients who had undergone lung transplant surgery at the University of Pennsylvania Medical Center between November 1991 and November 1996.
How was the study done?
After lung transplantation, patients had routine blood tests to measure ammonia levels. The researchers also collected other essential medical information about the patients over the course of their hospital stay and after their discharge.
What did the researchers find?
Six of the 145 patients developed high ammonia levels within the first 26 days after transplantation. Within 1 month after surgery, 4 (67%) of the 6 patients with high ammonia levels died compared with 24 (17%) of the 139 patients whose ammonia levels did not increase. Patients with major intestinal complications (such as bleeding or perforation) or infections, who required intravenous feeding, or who developed high blood pressure in the arteries of the lungs were more likely to develop high blood ammonia levels than patients without those conditions. A high blood ammonia level was recognized early and treated in one of the two patients who survived.
What were the limitations of the study?
This study cannot tell us whether high ammonia levels develop before or after other complications of lung transplantation. It also does not tell us whether treatment for high ammonia levels in these patients would result in better outcomes.
What are the implications of the study?
A high blood ammonia level is a potentially fatal condition that develops in a small percentage of patients after lung transplantation, but more needs to be learned about the causes, meanings, and possible treatment of this condition. Doctors should be aware of this potential complication.
Article and Author Information
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The summary below is from the full report titled “Fatal Hyperammonemia after Orthotopic Lung Transplantation.” It is in the 15 February 2000 issue of Annals of Internal Medicine (volume 132, pages 283-287). The authors are G.R. Lichtenstein, Y.-X. Yang, F.A. Nunes, J.D. Lewis, M. Tuchman, G. Tino, L.R. Kaiser, H.I. Palevsky, R.M. Kotloff, E.E. Furth, J.E. Bavaria, M.M. Stecker, P. Kaplan, and G.T. Berry.
- Copyright ©2004 by the American College of Physicians
