Comparing the effects of dopexamine and dobutamine on splanchnic parameters in patients with severe sepsis

Introduction

This prospective randomized study was designed to assess the effect of low dose dopexamine Hcl (dp) and dobutamine Hcl (db) on splanchnic blood flow as measured by gastric intramucosal pH (pHi), hepatic metabolism of lidocain to monoethylglicinexylidide (MEGX), and plasma disappearance rate of indocyanine green (PDR/ICG).

Methods

16 critically ill patients, meeting the criteria for the diagnosis of severe sepsis, were assigned either to receive dopexamine (1 μg/kg/min) or dobutamine (5 μg/kg/min). Baseline measurements of pHi, MEGX, PDR/ICG as well as hemodynamic, respiratory parameters, oxygen derived variables and arterial lactate were measured. At the end of a 2 h infusion of an appropriate drug, a repeated set of the measurements were taken.

Results

Both drugs produced significant increases in cardiac index, apparently due to a significant increase in heart rate. SVI (stroke volume index) remained unchanged with dopexamine, however some increase was observed with dobutamine. DO₂I (oxygen supply) increased similarly in both groups (16% dp, 19% db) with VO₂I (oxygen consumption) increasing more with db compared to dp. Lactate values after each drug administration appeared to be significantly lower than baseline values (dp 2.08 ± 0.53, db 2.50 ± 1.99 ± 0.99).

No significant improvement in the splanchnic parameters was observed with dopexamine. PHi increased significantly with db (7.26 ± 0.04 to 7.33 ± 0.07 P < 0.05). PDR/IICG and MEGX values showed significant increases with db (PDR/ICG from 15.5 ± 9.1 to 21.3 ± 10.3%; MEGX from 19.8 ± 11.2 to 28.8 ± 18.4 P < 0.05), and stayed constant with dp, however both parameters measured atbaseline were higher in dp group than in db group.

Conclusion

This study demonstrated the expected effects of each drug as mentioned in the previous studies. Our data showed that in severely septic patients, dobutamine leads to greater effectiveness in improving these accepted splanchnic parameters than dopexamine. However, how well and accurate these parameters reflect the abnormalities of splanchnic organ blood supply and their metabolism needs to be investigated by further studies.