Hypertonic/hyperoncotic resuscitation after intestinal superior mesentericartery occlusion: Early effects on circulation and intestinal reperfusion

The objective of the study was to determine the early effects of hypertonic /hyperoncotic starch resuscitation after 2 h occlusion of the superior mese nteric artery (SMA) in comparison to animals reperfused without treatment a nd isotonic resuscitation. SMA was clamped (18 pigs, 19-23 kg) for 2 h foll owed by a 2-h reperfusion period, which was initiated with isotonic (ISO) ( 35 mL/kg 0.9% NaCl and 5 mL/kg 10% hydroxyethyl starch within 30 min) or hy pertonic/hyperoncotic resuscitation (HHES) (7.5% NaCl/10% hydroxyethyl star ch within 5 min). Cardiac output (CO), mean arterial blood pressure (MAP), serum lactate, antimesenteric serosal Laser-Doppler values (LD), and intram ural pi-ii (tonometry) were measured. Without resuscitation at the onset of reperfusion MAP (70 +/- 3 mmHg) decreased to 40 +/- 3 mmHg and CO to 31% o f baseline values after 30 min. Serum lactate increased to 5.1 +/- 1.6 mmol /L without improvement. The decrease of CO was attenuated only during the i nitial 30 min of reperfusion in the ISO group, but significantly better cou nteracted by hypertonic/hyperoncotic resuscitation. Without treatment, LD f low of the ileum (baseline 23-27 LD units) recovered but intramural pH (pHi ) remained significantly decreased (7.26 +/- 0.05). With isotonic resuscita tion LD Values (21.8 +/- 2.1 LD units) and intramural pHi (7.09 +/- 0.14) d ecreased even more (P < 0.05) whereas the HHES group showed a significant h yperemic reaction and a normalization of the intramural pHi and serum lacta te within 30 min. Hypertonic/hyperoncotic resuscitation significantly impro ves MAP and CO during reperfusion shock and induces an immediate hyperemic reperfusion reaction of the intestinal microcirculation. Adequate isotonic fluid replacement in order to restore the postischemic plasma volume loss m ay cause a pronounced deterioration of intestinal perfusion.