Despite marked systemic hypotension, epidural anaesthesia did not affect intestinal oxygenation. There was no benefit obtained from volume loading.

Perioperative liver injury due to decreased perfusion may be an underlying mechanism behind the development of systemic inflammatory response syndrome. We designed this animal study to assess whether thoracic epidural anesthesia (TEA) impairs liver oxygenation due to induced hypotension. After ethical approval, 19 anesthetized and acutely instrumented pigs were randomly assigned to 3 groups (control and TEA alone versus TEA plus volume loading). Bupivacaine 0.5% 0.75 mL per segment was injected into the epidural space, aiming for a T5 to T12 block. After baseline values were obtained, measurements were repeated 60 and 120 min after epidural injection. TEA was associated with decreased mean arterial blood pressure but no change in total hepatic blood flow. Oxygen delivery to the liver and oxygen uptake remained unchanged. Liver tissue oxygen partial pressure did not decrease. The plasma indocyanine green disappearance rate remained stable. Volume loading before TEA did not relevantly affect total hepatic blood flow; it even decreased oxygen supply to the liver by hemodilution. We conclude that, despite decreased mean arterial blood pressure, TEA did not affect liver oxygenation. There was no clinically relevant effect of volume loading on total hepatic perfusion.

IntroductionAcute lung injury (ALI) is an inflammatory disorder of pulmonary or extrapulmonary origin. We have previously demonstrated that netrin-1 dampens murine ALI, and in an attempt to advance this finding into future clinical practice we evaluated whether netrin-1 would reduce alveolar inflammation during porcine ALI.MethodsThis was a controlled in vivo experimental study in pigs. We induced ALI through lipoploysaccharide (LPS) infusion (50 μg/kg) for 2 hours. Following this, we exposed animals to either vehicle, intravenous netrin-1 (netrin-1 i.v.) or inhaled netrin-1 (netrin-1 inh.). Serum samples and bronchoalveolar lavage (BAL) were obtained to determine levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, interleukin-6 and interleukin-8 at baseline and 6 hours following treatment. Myeloperoxidase activity (MPO) and protein levels were determined in the BAL, and tissue samples were obtained for histological evaluation. Finally, animals were scanned with spiral CT.ResultsFollowing LPS infusion, animals developed acute pulmonary injury. Serum levels of TNF-α and IL-6 were significantly reduced in the netrin-1 i.v. group. BAL demonstrated significantly reduced cytokine levels 6 hours post-netrin-1 treatment (TNF-α: vehicle 633 ± 172 pg/ml, netrin-1 i.v. 84 ± 5 pg/ml, netrin-1 inh. 168 ± 74 pg/ml; both P < 0.05). MPO activity and protein content were significantly reduced in BAL samples from netrin-1-treated animals. Histological sections confirmed reduced inflammatory changes in the netrin-1-treated animals. Computed tomography corroborated reduced pulmonary damage in both netrin-1-treated groups.ConclusionsWe conclude that treatment with the endogenous anti-inflammatory protein netrin-1 reduces pulmonary inflammation during the initial stages of ALI and should be pursued as a future therapeutic option.