Tezosentan normalizes hepatomesenteric perfusion in a porcine model of cardiac tamponade

Splanchnic Circulation and Intraabdominal Metabolism in Two Porcine Models of Low Cardiac Output

The impact of acute cardiac dysfunction on the gastrointestinal tract was investigated in anesthetized and instrumented pigs by sequential reductions of cardiac output (CO). Using a cardiac tamponade (n = 6) or partial inferior caval vein balloon inflation (n = 6), CO was controllably reduced for 1 h each to 75% (CO_75%), 50% (CO_50%), and 35% (CO_35%) of the baseline value. Cardiac output in controls (n = 6) was not manipulated and maintained. Mean arterial pressure, superior mesenteric arterial blood flow, and intestinal mucosal perfusion started to decrease at CO_50% in the intervention groups. The decrease in superior mesenteric arterial blood flow was non-linear and exaggerated at CO_35%. Systemic, venous mesenteric, and intraperitoneal lactate concentrations increased in the intervention groups from CO_50%. Global and mesenteric oxygen uptake decreased at CO_35%. In conclusion, gastrointestinal metabolism became increasingly anaerobic when CO was reduced by 50%. Anaerobic gastrointestinal metabolism in low CO can be detected using intraperitoneal microdialysis.

Consecutive Daily Measurements of Luminal Concentrations of Lactate in the Rectum in Septic Shock Patients

In a recent study we found no difference in the concentrations of luminal lactate in the rectum between nonsurvivors and survivors in early septic shock (<24 h). This study was initiated to investigate if there are any changes in the concentrations of luminal lactate in the rectum during the first 3 days of septic shock and possible differences between nonsurvivors and survivors. Methods. We studied 22 patients with septic shock in this observational study. Six to 24 h after the onset of septic shock the concentration of lactate in the rectal lumen was estimated by 4 h equilibrium dialysis (day 1). The rectal dialysis was repeated on day 2 and day 3. Results. The concentration of lactate in the rectal lumen did not change over the 3 days in neither nonsurvivors nor survivors. Rectal luminal and arterial lactate concentrations were not different. Conclusion. There was no change in the concentration of lactate in the rectal lumen over time in patients with septic shock. Also, there was no difference between nonsurvivors and survivors.

Lactate concentrations in the rectal lumen in patients in early septic shock

BACKGROUND

Previously, we observed that rectal luminal lactate was higher in non-survivors compared with survivors of severe sepsis or septic shock persisting >24 h. The present study was initiated to further investigate this tentative association between rectal luminal lactate and mortality in a larger population of patients in early septic shock.

METHODS

A prospective observational multicentre study of 130 patients with septic shock at six general ICU's of university hospitals. Six to 24 h after the onset of septic shock, the concentration of lactate in the rectal lumen was estimated by a 4-h equilibrium dialysis. Dialysate concentrations of lactate were determined using an auto-analyser.

RESULTS

The overall 30-day mortality was 32%, with age and Simplified acute physiology scores II and sequential organ failure assessment scores being significantly higher in non-survivors. In contrast, there were no differences in concentrations of lactate in the rectal lumen [2.2 (1.4-4.1) and 2.8 (1.6-5.1) mmol/l (P=0.34)] (medians and 25th-75th percentiles) or arterial blood [2.1 (1.4-4.2) and 2.0 (1.3-3.2) mmol/l (P=0.15)] between non-survivors and survivors. The rectal-arterial difference of the lactate concentration was higher in survivors. There were no differences in blood pressure, noradrenaline dose or central venous oxygen saturation between the groups.

CONCLUSION

In this prospective, observational study of unselected patients with early septic shock, there was no difference in the concentration of lactate in the rectal lumen between non-survivors and survivors.

TRIAL REGISTRATION

Clinicaltrials.gov (no: NCT00197938).