Glutamine (Gln)-supplemented perioperative total parenteral nutrition
(TPN) hai; been reported to reduce the loss of intramuscular glutamine
following routine surgery. This study investigates whether glutamine
supplemented TPN can alter muscle biochemistry acutely in the very sev
erely ill patient. Thirty-eight patients (age 19-77 yr; mean 55 yr), c
ritically ill (APACHE II range 8-31; median 17) admitted to the intens
ive care unit (ICU) were recruited to receive either conventional TPN
(CTPN) or an isonitrogenous, isoenergetic feed:supplemented with 25 g
crystalline L-glutamine per 24 h (GTPN) in a prospective. double blind
, bIock-randomized study. In a representative sample of these patients
, relatives consented to a paired muscle biopsy taken before feeding (
10 GTPN/9 CTPN patients; ICU Day 2-4) and repeated 5 days later (16 pa
tients; ICU Day 7-9). Muscle biopsies and matching plasma samples were
analyzed using a coupled glutaminase-glutamate dehydrogenase enzymati
c assay. A correction was made using sodium to account for the massive
changes in extracellular fluid volume. The average muscle Gin content
before feeding was very low. Between biopsies no consistent pattern o
f change was seen with or without exogenous Gln. It also proved diffic
ult in these very sick patients to correct a low plasma Gin with L-Gln
-TPN during the initial phase of the severe illness. TPN supplementati
on with 25 g/24 h, L-glutamine appears inadequate in the acute period
to counteract the muscle and plasma biochemical changes seen in these
patients. It is unknown whether ang larger dose could alter this state
.