Concurrent clinical and metabolic derangements in the newborn rat: a late phase sepsis model

Gram negative sepsis is a leading cause of human newborn morbidity and mortality. The clinical signs and glucose and lactate concentration during the late phase of newborn rat endotoxicosis has not been well characterized. In order to define a late phase model of sepsis, simultaneous clinical signs (loss of response to pain [RP] and/or righting reflex [RR]), and metabolic (glucose, lactate) concentrations were studied in the 10 day old Sprague-Dawley rat. The rats were fasted for four hours and then injected with either saline (control) or 0.1 mg per kg Salmonella enteritidis (LD90 @ 24) endotoxin intraperitoneally. Rats were then examined every 15 minutes beginning two hours post injection for the presence or absence of loss of RR and/or loss of RP. Central blood samples were collected for determination of glucose and lactate at the moment of loss of the predetermined clinical parameter. Metabolic parameters were also determined on saline treated controls time matched to the experimental groups. Rats were grouped as follows: GrI, (n = 10), saline three hours post injection; GrIII, (n = 10), saline five hours post injection; GrII, (n = 45), endotoxin at the moment of loss of RR; GrVI, (n = 14), endotoxin at 8.5 hrs post injection (termination of experiment, all with loss of RR); GrIV, (n = 11) endotoxin at loss of RP; and GrV, (n = 10) saline at 8.5 hr post injection.(ABSTRACT TRUNCATED AT 250 WORDS)