Abstract
OBJECTIVE: To investigate whether brief fasting before the induction of hypotension by non-lethal haemorrhage may induce translocation of enteric bacteria to mesenteric lymph nodes or blood in rats. DESIGN: Laboratory experiment. SETTING: University departments of surgery and microbiology, Sweden. MATERIAL: 39 Male Sprague-Dawley rats. INTERVENTIONS: 20 animals were fasted for 24 hours, all 39 then underwent controlled haemorrhage for 60 minutes that reduced the blood pressure to 55 mm Hg. MAIN OUTCOME MEASURES: Differences in blood loss, blood glucose concentrations, and packed cell volume; and aerobic cultures of mesenteric lymph nodes and blood. RESULTS: Fasted rats (n = 20) lost 2.3% of blood volume compared with 2.8% in fed rats (p less than 0.001). Packed cell volume dropped by 11.3% in fasted rats and 16.5% in fed rats (p less than 0.001). Glucose concentrations rose by 7.0 mmol/l in fasted rats compared with 21.0 mmol/l in fed rats (p less than 0.001). Mesenteric lymph nodes contained enteric bacteria in 14/20 fasted rats compared with 6/19 fed rats (p less than 0.05). In 4 fasted rats blood cultures grew pathogenic bacteria compared with no fed rats (p = 0.11). The number of bacteria found in mesenteric lymph nodes was significantly greater in fasted than in fed rats (p = 0.01). CONCLUSIONS: Brief fasting before hypotension caused by non-lethal haemorrhage was associated with significantly increased bacterial translocation compared with fed animals. Increases in blood glucose concentrations and plasma refill may have had a protective effect in fed rats. These experiments may be of clinical relevance as elective operations are usually preceded by overnight fasting.