Evaluation of postinjury hepatocyte function by central amino acid clearance.
It has been demonstrated by other investigators that central plasma clearance of amino acids accurately predicts hepatocyte function in patients with liver disease and correlates with clinical outcome. This methodology has not heretofore been studied in the trauma patient. It is our hypothesis that central amino acid clearance in trauma patients is more reflective of hepatocyte function than traditional liver function tests. We examined the plasma amino acid clearance rates using L-[1-13C]phenylalanine. Clearance rates were compared to standard liver function tests (LFTs) and the sensitivity and predictability of the technique were determined. The study was conducted on uninjured control subjects and in seriously injured patients, both with and without significant liver injuries. Compared to baseline values in the control group, initial phenylalanine breath scores were reduced in the injured, but exceeded control levels at 7 days postinjury. These changes were statistically significant. There was no difference between those with and without liver trauma. LFTs showed inconsistent and conflicting results. Thus, central amino acid clearance measured by L-[1-13C]phenylalanine oxidation is depressed immediately following injury but reaches supranormal levels at 7 days postinjury. Compared to LFTs, amino acid clearance suggests initial hepatocyte suppression followed by hyperactivity and is a more accurate determinant of hepatocyte function.
Maull
Kimball I
KI
Carraway Methodist Medical Center, Birmingham, Alabama 35234, USA. maullk@carraway.com
Long
Calvin L
CL
Wagner
David A
DA
Hunt
Charles A
CA
Scanlon
Patrick H
PH
Laws
Henry L
HL
D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000596:Amino Acids / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood; D001663:Bilirubin / Q000097:blood; D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis; D002247:Carbon Isotopes; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008099:Liver / Q000293:injuries* / Q000378:metabolism; D008111:Liver Function Tests / Q000379:methods*; D008657:Metabolic Clearance Rate; D010649:Phenylalanine / Q000493:pharmacokinetics; D012709:Serum Albumin / Q000032:analysis; D012720:Severity of Illness Index
D000596:Amino Acids; D002247:Carbon Isotopes; D012709:Serum Albumin; D002245:Carbon Dioxide; D010649:Phenylalanine; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D001663:Bilirubin