Abstract
Lung mechanics are affected by acute haemorrhage and consecutive replacement with autologous blood (Bayat, S. et al. J Appl Physiol 2011; 111:458-64). We aimed at comparing the respiratory mechanical changes following fluid resuscitation with autologous blood (n=8, Group B), colloid (HES 6% 130/0.4, n=8, Group CO) or crystalloid solution (0.9% NaCl, n=9, Group CR) after acute haemorrhage.
Anaesthetised, ventilated rats were bled in 6 sequential steps, each manoeuvre targeting a loss of 5% of total blood volume, which was then replaced stepwise by one of the three solutions above. After each step, airway resistance (Raw), tissue damping (G) and elastance (H) were determined by forced oscillations. Perivascular oedema area was assessed from lung histology.
Raw decreased in all groups following blood loss (-20.3±1.9[SE]% vs. control, p<0.05) and was normalized only by colloid (5.5±3.8% vs. control, NS), but was not affected by blood (-21.7±2.9%). Crystalloid had an intermediate reversal effect (-8.4±4.9%, NS). G and H increased following both blood loss and replacement, with significantly higher elevations of H in groups CO (37±6.6%) and CR (40±4.4%) vs. Group B (23±3.5%, p<0.001). More severe perivascular oedema was observed by the histological analysis in groups CR and CO than in group B (p<0.05).
We conclude that fluid resuscitation with colloid solution normalizes the airway properties, while persistent airway dilation remains after blood replacement with crystalloid solution. Conversely, both fluid replacement strategies deteriorate respiratory tissue mechanics due to the development of perivascular oedema.
Grants: OTKA K81169, TÁMOP 4.2.2.A-11/1/KONV-2012-0052.
- © 2014 ERS
