Effects of three different resuscitation regimens on jejunal tissue oxygen supply after hemorrhagic shock

Introduction

In this study we evaluated effects of blood (B; n = 7), gelatine (G; n = 8) and Ringer's lactate (R; n = 8) resuscitation on jejunal microvascular blood flow (PU), tissue microvascular hemoglobin oxygen saturation (HbO₂t) and jejunal mucosal tissue oxygen tension (PO₂muc) after severe haemorrhage (50% of estimated blood volume) in pigs.

Methods

Animals were anaesthetised, paralysed, and normoventilated. A small segment of the jejunal mucosa was exposed by midline laparotomy and antimesenteric incision. PO₂muc was measured using Clark-type surface oxygen electrodes. HbO₂t and PU were determined by tissue reflectance spectrophotometry and laser doppler velocimetry. Systemic hemodynamics, mesentericvenous acid base and blood gas variables as well as systemic acid base and blood gas variables were recorded. Measurements were performed after a resting period, after a 50 min period of haemorrhage (H) and after resuscitation with B, G and R to achieve baseline pulmonary capillary wedge pressures at 70, 90, 110 and 130 min, respectively. ANOVA was performed to analyse differences in mean values between and within groups. Multiple comparisons were done by two tailed Dunnett's t-test followed by Bonferoni correction. P ≤ 0.05 was considered significant. Data are presented as means ± SD.

Results

H resulted in significant hypotension and decreased systemic blood flow which was reversed after resuscitation in all groups. At baseline we observed no differences in PO₂muc (B: 29± 5.9 mmHg), HbO₂t (B: 48.5 ± 6.7%) and microvascular blood flow (B: 253 ± 66 PU) between groups. H equally and significantly decreased PU, PO₂muc and HbO₂t in B, G, R animals. However, after resuscitation R animals had significantly lower HbO₂t (time point 130 min; R: 25 ± 9%) when compared with B and G animals (time point 130 min; B: 39 ± 9%; G: 33 ± 10%). PO₂muc decreased similar in B and R animals after resuscitation (time point 130 min; B: 15 ± 6 mmHg; R 14 ± 7 mmHg). However, in G animals a trend towards higher PO₂muc values (time point 130 min; G: 20 ± 9 mmHg) was observed during resuscitation. There were no differences concerning microvascular blood flow during resuscitation.

Conclusion

Resuscitation after severe haemorrhage using whole blood, Ringer's lactate or gelatine results in distinct changes of jejunal tissue oxygen supply. Whole blood resuscitation favourably preserved HbO₂t without affecting PO₂muc while use of gelatine only, demonstrated a trend towards higher PO₂muc values when compared with R and B animals. Therefore type of resuscitation fluid seems to have some impact on tissue oxygen supply within the gastrointestinal tract.

Supported by a Lorenz Böhler Fonds 2000