Increased colorectal permeability in patients with severe sepsis and septic shock

Objective To develop a method for the assessment of colorectal permeability in septic patients.Design and setting Observational study in ICUs at two university hospitals.Participants Nine patients with septic shock and abdominal focus of infection, 7 with severe sepsis and pulmonary focus and 8 healthy subjects.Measurements and results Colorectal permeability was assessed as the initial appearance rate of ^99mTc-DTPA in plasma after instillation into the rectal lumen and as the cumulative systemic recovery at 1 h. To calculate the latter, volume of distribution and renal clearance of ^99mTc-DTPA was estimated by an i. v. bolus of ⁵¹Cr-EDTA. The initial rate of permeability was increased in patients with septic shock and severe sepsis compared with controls [29.0 (3.7–83.3), 20.6 (3.6–65.5) and 6.0 (2.2–9.6) cpm ml⁻¹ min⁻¹, respectively, p < 0.05)] with a positive linear trend (r ² = 0.27, p = 0.01) and correlated to L-lactate concentrations in the rectal lumen (r ² = 0.39, p < 0.05). The cumulative permeability was also increased in patients with septic shock and severe sepsis compared with controls [2.07 (0.05–15.7), 0.32 (0.01–1.2) and 0.03 (0.01–0.06)‰, respectively, p < 0.01] and correlated to the initial permeability rate (r ² = 0.26, p = 0.01).Conclusions In septic patients, the systemic recovery of a luminally applied marker of paracellular permeability was increased and related to the luminal concentrations of L-lactate and possibly to disease severity. This suggests that the assessment of colorectal permeability by systemic recovery of ^99mTc-DTPA is valid and that metabolic dysfunction of the mucosa contributes to increased permeability of the large bowel in patients with severe sepsis and septic shock.