Peripheral postcapillary venous pressure: A new, more sensitive monitor of effective blood volume during hemorrhagic shock and resuscitation

Peripheral postcapillary venous pressure (PCVP) and mixed venous oxygen saturation (Sv̄O₂ or PASO₂) have been shown to be sensitive indicators of volume status and appear to reflect the adequacy of peripheral perfusion during controlled bleeding. This study demonstrates that in an open-chest dog model with controlled venous return, PCVP is closely and linearly (r² = 0.6) correlated with cardiac output (CO). Furthermore, oxygen saturation as measured in the central venous system (CVSO₂) and peripheral vein (PVSO₂) were found to be closely and linearly related to PASO₂ (r = 0.72 to 0.99 and 0.91 to 0.98, respectively). Thus PCVP, CVSO₂, and PVSO₂ represent easily and safely obtainable parameters that closely reflect major physiologic variables. During resuscitation after controlled hemorrhage, the PCVP and PVSO₂ accurately reflected the restoration of blood volume and were as good as CO and central saturations. Central venous and pulmonary wedge pressures both poorly reflected the return to full volume repletion (P<0.01). Thus, PCVP and PVSO₂ seem to be reliable indices of volume status and perfusion and do not require invasive, central monitoring.