FOOD-DEPRIVATION INCREASES BACTERIAL TRANSLOCATION AFTER NONLETHAL HEMORRHAGE IN RATS

Objective. To investigate whether brief fasting before the induction o f hypotension by non-lethal haemorrhage may induce translocation of en teric bacteria to mesenteric lymph nodes or blood in rats. Design: Lab oratory experiment. Setting: University departments of surgery and mic robiology, Sweden. Material: 39 Male Sprague-Dawley rats. Intervention s: 20 animals were fasted for 24 hours, all 39 then underwent controll ed haemorrhage for 60 minutes that reduced the blood pressure to 55 mm Hg.Main outcome measures: Differences in blood loss, blood glucose co ncentrations, and packed cell volume; and aerobic cultures of mesenter ic lymph nodes and blood. Results: Fasted rats (n = 20) lost 2.3% of b lood volume compared with 2.8% in fed rats (p < 0.001). Packed cell vo lume dropped by 11.3% in fasted rats and 16.5% in fed rats (p < 0.001) . Glucose concentrations rose by 7.0 mmol/l in fasted rats compared wi th 21.0 mmol/l in fed rats (p < 0.001). Mesenteric lymph nodes contain ed enteric bacteria in 14/20 fasted rats compared with 6/19 fed rats ( p < 0.05). In 4 fasted rats blood cultures grew pathogenic bacteria co mpared with no fed rats (p = 0.11). The number of bacteria found in me senteric lymph nodes was significantly greater in fasted than in fed r ats (p = 0.01). Conclusions: Brief fasting before hypotension caused b y non-lethal haemorrhage was associated with significantly increased b acterial translocation compared with fed animals. Increases in blood g lucose concentrations and plasma refill may have had a protective effe ct in fed rats. These experiments may be of clinical relevance as elec tive operations are usually preceded by overnight fasting.