INCREASED INTESTINAL PERMEABILITY FOLLOWING BLUNT AND PENETRATING TRAUMA

Objectives: To determine changes in the absorption of lactulose and ma nnitol in patients undergoing laparotomy following blunt or penetratin g trauma and to correlate any changes in permeability with the severit y of injury. Design: Nonrandomized study within patient control. Patie nts: Consecutive patients admitted to the trauma unit following blunt or penetrating trauma with intra-abdominal injuries warranting emergen t celiotomy and jejunal access. Interventions: Intestinal permeability was measured in 18 patients within 48 hrs posttrauma by the bolus inf usion into the jejunum of nonmetabolized probe molecules, lactulose (m olecular weight of 342) and mannitol (molecular weight of 182). Becaus e several patients did not tolerate the bolus infusion, a 3-hr continu ous infusion of the probe molecules was used in the last eight patient s entered into the study, Intestinal permeability was reassessed befor e discharge or on days 10 to 12. Measurements and Main Results: There was a decrease in urinary lactulose excretion and the lactulose/mannit ol ratio between the initial posttrauma measurement and the follow-up permeability measurement using both the bolus infusion (lactulose: ini tial 0.13 +/- 0.032 vs. follow-up 0.047 +/- 0.012 mmol/6 hrs, p less t han or equal to .05; lactulose/mannitol: initial 0.067 +/- 0.012 vs. f ollow-up 0.044 +/- 0.012, p = .11) and the continuous infusion (lactul ose: initial 0.044 +/- 0.013 vs, follow-up 0.014 +/- 0.002 mmol/2 hrs, p less than or equal to .05; lactulose/mannitol: initial. 0.055 +/- 0 .020 vs. follow-up 0.015 +/- 0.007, p less than or equal to .05). Urin e excretion of mannitol was not significantly different between posttr auma and follow-up measurements of intestinal permeability, regardless of the technique used to infuse the lactulose and mannitol, Although the decrease in lactulose and the lactulose/mannitol ratio was signifi cant, only one third of the patients had dramatically increased permea bility at the initial measure. Abdominal Trauma Index and Injury Sever ity Score did not correlate with urinary lactulose excretion or the la ctulose/mannitol ratio. Patient tolerance of jejunal administration of lactulose and mannitol was better, using a 3-hr continuous infusion o f a dilute solution compared with bolus infusion. Conclusions: Intesti nal permeability is increased in the first 48 hrs posttrauma and decre ases with recovery. Although one third of the patients had highly incr eased lactulose/mannitol ratios posttrauma, severity of injury, assess ed by common scoring techniques, did not correlate with the degree of permeability. Tolerance to jejunal administration of lactulose and man nitol is improved with a slow infusion of a dilute solution over a 3-h r period compared with bolus administration.