Physicochemical changes during haemorrhage and following infusion

Area of Science:

• Physiology
• Hemodynamics
• Fluid Resuscitation

Background:

• Interstitial fluid pressure (IFP) and plasma colloid osmotic pressure (plasma COP) are crucial determinants of fluid exchange.
• Understanding their behavior during hemorrhage and resuscitation is vital for effective clinical management.

Purpose of the Study:

• To investigate the effects of acute hemorrhage and various fluid resuscitation strategies on IFP and plasma COP in a canine model.

Main Methods:

• Measurements of IFP and plasma COP in dogs subjected to acute hemorrhage.
• Assessment following infusions of physiological saline, 10% dextran 40 in saline, and 3% dextran 40 in lactated Ringer's solution.

Main Results:

• Hemorrhage decreased IFP, plasma COP, total protein, and albumin, while increasing glucose and osmotic pressure.
• Saline infusion elevated IFP and decreased plasma COP and protein concentrations, with a correlation between saline volume and IFP increase.
• Dextran 40 in saline markedly increased plasma COP and decreased IFP; dextran 40 in Ringer's solution had minimal early effect on IFP but increased plasma COP.

Conclusions:

• Different fluid resuscitation strategies exert distinct effects on interstitial and plasma osmotic pressures.
• Dextran-containing solutions appear more effective at restoring plasma COP compared to saline alone.
• These findings have implications for optimizing fluid therapy in hypovolemic states.