Critical Care and Shock

Prediction of colloid osmotic pressure from albumin and/or hemodynamics in pigs undergoing hemorrhagic shock

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Background and purpose: Colloid osmotic pressure (COP) is strongly affected during by hemorrhagic shock (HS) and imbalances may result in pulmonary and systematic oedema. Measurement of COP is therefore crucial in order to monitor changes and to react to critical levels. The aims of this study were to examine the time-course effects on COP and albumin in pigs undergoing controlled HS, and to investigate whether albumin and/or hemodynamic parameters are relevant predictors of COP during HS.
Methods: 18 pigs randomly assigned in a blinded manner to one of three groups. Group 1: sham (n=4); group 2: hemorrhage control (n=7) and group 3: hemorrhage + adenosine, lidocaine and Mg2+/adenosine, lidocaine (ALM/AL) (n=7). COP was measured using a commercially available oncometer.
Results: Group 2 experienced the greatest change in absolute and relative COP-values during the experiment, while group 1, as expected, experienced the smallest change. Strong correlations were seen between COP and albumin for group 2 (0.84, p<0.001) and for group 3 (0.82, p<0.001), whereas moderate to negligible correlations were seen between COP and the hemodynamic parameters.
Conclusion: Pigs subjected to HS compensated unexpectedly well compared to pigs not exposed to HS (sham). It is possible to predict COP from albumin, which may be clinically relevant in situations where an oncometer is not accessible. Further studies are needed if these findings are to be transferred to humans.