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Erschienen in:
01.11.2004 | Experimental
Effects of thoracic epidural anaesthesia on intestinal microvascular perfusion in a rodent model of normotensive endotoxaemia
Erschienen in: Intensive Care Medicine | Ausgabe 11/2004
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Objective
To investigate whether sympathetic blockade by means of thoracic epidural anaesthesia (TEA) increases intestinal perfusion during normotensive endotoxaemia.
Design
A prospective, randomised and controlled animal study.
Setting
Animal laboratory in a university hospital.
Subjects
Sprague-Dawley male rats.
Interventions
The rats were anaesthetised with urethane and ketamine, mechanically ventilated and haemodynamically monitored. Lidocaine or saline were infused continuously via thoracic epidural catheters followed by a continuous intravenous infusion of Escherichia coli lipopolysaccharide (1.5 mg/kg per h). Densities of perfused and non-perfused capillaries (i.e., with and without erythrocyte perfusion, respectively) as well as erythrocyte velocity in both the mucosa and the muscularis of the terminal ileum were determined using intravital microscopy.
Measurements and results
Measurements were performed at baseline, after 30 min of epidural infusion as well as after 60 and 120 min of lipopolysaccharide infusion. In animals receiving TEA, mean arterial pressure and heart rate were significantly reduced throughout the experiment. In the muscularis the endotoxaemia-induced increase in non-perfused capillaries was absent with epidural lidocaine (0 [0/0] versus 39 [36/137] cm-1, median [25th/75th percentile]), whereas in the mucosa perfused capillary density declined to a greater extent than in controls (−47 [−53/−23]%) versus −19 [−34/+10]%, p<0.05). Erythrocyte velocity decreased with endotoxaemia and was not influenced by epidural lidocaine.
Conclusions
Microvascular perfusion data during endotoxaemia show a redistribution of blood flow towards the mucosa. TEA seems to impede this redistribution resulting in improved muscularis and worsened mucosal microvascular perfusion.