Research

Liver dysfunction after lung recruitment manoeuvres during pressure-controlled ventilation in experimental acute respiratory distress

Markus Kredel^{* 1} , Ralf M Muellenbach^{* 1} , Robert W Brock² , Hans-Hinrich Wilckens¹ , Joerg Brederlau¹ , Norbert Roewer¹ and Christian Wunder¹

¹University of Würzburg, Department of Anaesthesiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany

²University of Arkansas for Medical Sciences, Department of Pharmacology and Toxicology, 4301 Markham St., Little Rock, AR, USA

author email corresponding author email* Contributed equally

Critical Care 2007, 11:R13doi:10.1186/cc5674

Published:	29 January 2007

See related letter by Eisenhut, http://ccforum.com/content/11/2/412

Abstract

Introduction

Consequences of lung recruitment with prolonged high positive end-expiratory pressure (PEEP) ventilation for liver function are unclear. We therefore investigated liver dysfunction during two different ventilation treatment regimens of experimental acute respiratory distress syndrome.

Methods

Sixteen anaesthetised juvenile pietrain pigs were ventilated in the pressure-controlled mode (PCV) with an inspiratory fraction of oxygen (FiO₂) of 1.0, a respiratory frequency of 30 per minute, a tidal volume of 6 ml/kg, and a PEEP of 5 cm H₂O. After lung injury was induced by repeated pulmonary lavage with normal saline, animals were randomly assigned into two groups (n = 8 each) for a 24-hour trial: PCV (unchanged ventilation) and PCV with recruitment (PCV+R) (starting with a sustained inflation of 50 cm H₂O for 1 minute, the ventilation was continued while increasing PEEP in increments of 3 cm H₂O every 15 minutes as long as arterial oxygen tension [PaO₂] improved). After recruitment, FiO₂ was reduced to 0.4 and the PEEP was lowered every 15 minutes until PaO₂ decreased to 12.0 to 14.7 kPa (90 to 110 torr). Serum levels of hyaluronic acid (HA), routine liver serum markers, and plasma disappearance rate of indocyanine green (ICG) were tested before and after lung injury, and 6 and 18 hours after randomisation. Liver serum markers were also tested at 24 hours. Paraffin sections of liver tissue stained by haematoxylin and eosin were made after euthanisation.

Results

The PCV+R group exhibited more polymorphonuclear neutrophils and lymphocytes in the liver sinusoids: median score (interquartile range) of 1.5 (1.4 to 1.5) compared to 0.9 (0.7 to 1.1) (p = 0.01). Elevation of bilirubin, aspartate aminotransferase, and lactate dehydrogenase was more prominent in the PCV+R group. Plasma disappearance rate of ICG indicated no liver dysfunction. HA levels in the PCV+R group gradually increased and were significantly higher (p < 0.001) at 6 and 18 hours with 59 (57 to 64) and 75 (66 to 84) ng/ml, respectively, than in the PCV group with 34 (32 to 48) and 41 (38 to 42) ng/ml, respectively.

Conclusion

The PCV+R group showed a more prominent inflammatory reaction in their liver sinusoids accompanied by increased serum levels of liver enzymes and HA. Therefore, recruitment with higher PEEP levels for treatment of respiratory failure might lead to liver dysfunction.