PLASMA α-AMINO ACID NITROGEN AND SERUM LIPIDS OF SURGICAL PATIENTS

Abstract

In plasma of patients who had acute infections or had had injuries or operations, the concn. of [alpha]-amino acid N was usually within or below the normal range. Such a reduction of amino acids might be a general reaction to injury, and associated with N losses usually encountered in disease and after trauma. [alpha]-Amino acid N of plasma of 30 patients was measured post-absorptively prior to operation, the following morning, and on some subsequent morning during recovery. In 10 other patients, plasma [alpha]-amino acid N was measured the morning after operation and during convalescence. Serum lipids of 9 patients were measured on the morning of operation, and on 2 succeeding mornings. Plasma a-amino. acid N falls abruptly after injury, and remains low until recovery is well advanced, even while N catabolism is greatly increased by admn. of high protein diets. The extent of the abrupt fall is directly proportional to the severity of the operative procedure, and roughly inversely proportional to the initial amino acid concn. The latter reflects the patient''s pre-operative condition. If this is normal, the plasma [alpha]-amino acid N is greater than 4.0 mg. %. If the patient is seriously ill before operation, the a-amino acid N is less than 4.0 mg. % before operation. If it is already greatly reduced it may fall no further after operation. After injury, serum, total and free cholesterol, lipid phosphorus and fatty acids diminish by small but unequivocal decrements. The lipid components are proportionally affected without distortion such as occurs in liver disease.