Systemic and microcirculatory effects of autologous whole blood resuscitation in severe hemorrhagic shock

Systemic and microcirculatory effects of autologous whole blood resuscitati on in severe hemorrhagic shock. Am. J. Physiol. 276 (Heart Circ. Physiol. 4 5): H2035-H2043, 1999. - Systemic and microcirculatory effects of autologou s whole blood resuscitation after 4-h hemorrhagic shock with a mean arteria l pressure (MAP) level of 40 mmHg were investigated in 63 conscious Syrian golden hamsters. Microcirculation of skeletal skin muscle and subcutaneous connective tissue was visualized in a dorsal skinfold. Shed blood was retra nsfused within 30 min after 4 h. Animals were grouped into survivors in goo d (SG) and poor condition (SP) and nonsurvivors (NS) according to 24-h outc ome after resuscitation and studied before shock, during shock (60, 120, an d 240 min), and 30 min and 24 h after resuscitation. Microvascular and inte rstitial Po-2 values were determined by phosphorescence decay. Shock caused a significant increase of arterial Po-2 and decrease of Pco(2), pH, and ba se excess. In the microcirculation, there was a significant decrease in blo od flow ((Q) over dot(B)), functional capillary density (FCD; capillaries w ith red blood cell flow), and interstitial Po-2 [1.8 +/- 0.8 mmHg (SG), 1-. 3 +/- 1.3 mmHg (SP), and 0.9 +/-. 1.1 mmHg (NS) vs. 23.0 +/- 6.1 mmHg at co ntrol]. Blood resuscitation caused immediate MAP recompensation in all anim als, whereas metabolic acidosis, hyperventilation, and a significant inters titial Po-2 decrease (40-60% of control) persisted. In NS (44.4% of the ani mals), systemic and microcirculatory alterations were significantly more se vere both in shock and after resuscitation than in survivors. Whereas in SG (31.8% of the animals) there was only a slight (15-30%) but still signific ant impairment of microscopic tissue perfusion ((Q) over dot(B), FCD) and o xygenation at 24 h, SP (23.8% of the animals) showed severe metabolic acido sis and substantial decreases (greater than or equal to 50%) of FCD and int erstitial Po-2. FCD, interstitial Po-2, and metabolic state were the main d eterminants of shock outcome.