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 (99m)Tc-DTPA in plasma after instillation into the rectal lumen and as the cumulative systemic recovery at 1h. To calculate the latter, volume of distribution and renal clearance of (99m)Tc-DTPA was estimated by an i.v. bolus of (51)Cr-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) per thousand, 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 (99m)Tc-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.