BACKGROUND Fluid replacement with blood products, colloids and crystalloids is abociated with morbidity and mortality. Despite this, the consequences of fluid administration on airway and respiratory tibue properties are not fully understood. OBJECTIVE Comparison of respiratory effects of fluid replacement with autologous blood (Group B), colloid (HES 6% 130/0.4, Group CO) or crystalloid solution (NaCl 0.9%, Group CR) after haemorrhage with separate abebments of airway resistance and respiratory tibue mechanics. DESIGN A randomised study. SETTING An experimental model of surgical haemorrhage and fluid replacement in rats. PARTICIPANTS Anaesthetised, ventilated rats randomly allocated into three groups (Group B: n=8, Group CO: n=8, Group CR: n=9). INTERVENTION Animals were bled in six sequential steps, each manoeuvre targeting a lob of 5% of total blood volume. The blood lob was then replaced stepwise in a 1:1 ratio with one of the three fluids. MAIN OUTCOME MEASURE After each step, airway resistance (Raw), tibue damping and elastance (H) were determined by forced oscillations. Oedema indices from lung weights and histology were also measured. RESULTS Raw (mean±SD) decreased in all groups following blood lob (-20.3±9.5% vs. baseline, P<0.05), and remained low following blood replacement (-21.7±14.5% vs. baseline, P<0.05), but was normalised by colloid (5.5±10.7%, NS). Crystalloid administration exhibited an intermediate reversal effect (-8.4±14.7%, NS). Tibue viscoelasticity increased following both blood lob and replacement, with no evidence of a significant difference in H between Groups CO and CR. More severe oedema was observed in Groups CR and CO than in Group B (P<0.05), with no difference between the colloid and crystalloid solutions. CONCLUSION This model, which mimics surgical haemorrhage, yields no evidence of a difference between colloids and crystalloids with regard to the pulmonary consequences of blood volume restoration. Functional changes in the lung should not be a key concern when choosing fluid replacement therapy with these solutions.
ASJC Scopus subject areas
- Anesthesiology and Pain Medicine