The effect of short term postoperative intravenous feeding upon cell-mediated immunity and serum suppressive activity in well nourished patients.

Thirty-four patients undergoing elective abdominal aortic aneurysmectomy were studied, and they were randomly allocated to a "fed group receiving amino acid dextrose solutions intravenously and fat emulsions or an "unfed" group receiving standard postoperative care. Cell-mediated immunity was measured by lymphocyte count, the in vitro response to the T-cell mitogen PHA and determination of T-cell subsets using monoclonal antibodies. Serum suppressive activity was measured by the ability of the sera of the patient to suppress the response of normal lymphocytes to PHA. Feeding was continued for three to five days postoperatively until satisfactory oral intake was achieved. There was no significant improvement in lymphocyte count or blastogenesis postoperatively in the "fed" group, and operation did not lead to any alteration in the ratio of T-cell subsets, although there was a fall in T-cell count (OKT3 positive cells). We conclude that short term parenteral nutrition in well nourished patients, postoperatively, does not abrogate the depression of cell-mediated immunity which occurs after extensive operative procedures.