Effects of corlopam infusion on pHi and ΔO₂: a randomized controlled clinical trial. Preliminary data

Introduction

The hepatosplanchnic region is quite important in the physiopathology of shock, trauma, SIRS and sepsis [1]. The intestinal mucosa is one of the first parenchimis that are influenced by the alterations of the perfusion and/or splanchnic oxygenation [2]. Particularly, a pHi < 7.1 for a period greater than 2 hours, defined as sigmoid ischemia of low degree, is predictive for major complications and death [3].

Fenoldopam has been demonstrated to improve glomerular perfusion through D₁ receptors, which are present also in the mesenteric region.

The purpose of our study is to verify whether fenoldopam infusion during abdominal aortic surgery can prevent gut ischemia.

Materials and methods

It is a prospective, controlled, randomized clinical trial on a preliminary series of 14 patients operated for abdominal aortic aneurysm. These patients were monitored with a sigmoid tonometer and with a NiCO system to measure cardiac index (CI). Patients just after anesthesia induction were randomized, allocated in two groups: one receiving corlopam at the dosage of 0.05 μg/kg per min (Group A) and the other receiving placebo (Group B). ΔO₂, pHi and CO were detected at the following times: just after the anesthesia inducion (t0), before aortic clamping (t1), 30 min after aortic clamping (t2), and just after the operation (t3). At these times an arterial sample was taken to detect arterial blood lactate, tumor necrosis factor alpha (TNF-α), and interleukin-1B, interleukin-6 and interleukin-8 (IL-1β, IL-6, IL-8). At T1 and T2 a portal blood sample was taken to detect portal blood lactate, TNF-α, IL-1β, IL-6, IL-8. At each time point medians of pHi, ΔO₂, systemic and portal lactate, and hemoglobin (Hb) were calculated for both groups of patients. The trend of pHi was determined with the Friedman test and Dunn's post-test. Median comparison was performed using the two-tailed non-parametric Mann–Whitney test. The Fischer exact test was used to compare a possible abnormal distribution of pHi and/or ΔO₂ within groups of patients.

Results

Phi decreased significantly at T2 in both groups (P < 0.01), but at T3 was significantly higher, compared with T0, only in Group B (P < 0.05). ΔO₂ did not increase significantly during aortic clamping in Group A, while in Group B at T2 it increased significantly (P < 0.01). CI decreased significantly in both groups at T2 (P < 0.05). Portal lactates were significantly higher in group B at T1 (P < 0.05), but at T2 there was not any significant difference. The arterial lactates trend was similar in the two groups. Any significant difference could be found for cytokines between the two groups.

Conclusions

From these preliminary data it seems that corlopam can ameliorate gut perfusion, as suggested by the increase of pHi and ΔO₂, even if these data have to be confirmed on a larger number of patients. After that other work must be done to investigate whether corlopam infusion can increase the outcome, that is morbidity and mortality, of patients undergoing abdominal aorta aneurysm.