Bleeding in the surgical patient

This article has been reviewed by the NeuroWiki Editorial Board

1. Classes of hemorrhage (Note: blood volume in adults is 75 cc/kg)
   1. I – 0-15% blood volume loss – tachycardia
   2. II – 15-30% blood volume loss – tachycardia, prolonged capillary refill (>2 seconds), narrow pulse pressure (increased diastolic pressure), decreased urine output (20-30 ml/h, splanchnic hypoperfusion (intestinal the first to occur)
   3. III – 30-40% blood volume loss – decompensated hypovolemic shock- hypotension and decreased urinary output (5-15 ml/h)
      1. Note: in children normal systolic BP = 70 + (2*age in years) and proper endotracheal tube size = age in years/4 + 4 (in mm)
   4. IV - > 40% blood volume loss - hypotension, urinary output < 5 ml/h, irreversibble changes are possible; coma, confusion
2. Invasive hemodynamic measures: central venous catheter allows measurement of central venous oxyhemoglobin saturation (ScvO2), central venous pressure (CVP)which can provide qualitative information about the cardiac filling pressure only at extreme values: very high (CVP>15 mmHg) or very low (CVP=0-1 mmHg); intermediate -range measurements are not interpretable because of the influence of ventricular compliance.
3. Two acid-base parameters are useful: arterial base deficit and arterial lactate
4. Resuscitation
   1. Trendelenburg position- - not proven effective
   2. Cannulation of peripheral veins with short, large bore catheters is more effcient than cannulation of large centaral veins with long, thin catheters
   3. Goals: cardiac output (CO) and hemoglobin (Hb) concentration augmentaton, in order to improve tissue oxygenation
      1. cardiac output augmentation: colloid fluids ( add to the plsama volume) and cristalloid fluids (add to the interstitial space; the volume of the cristalloid shoud be three times greater than the volume of colloid fluids infused for equivalent effects on the CO.
      2. Hb augmentation- transfusion- triggered rather by the O2 extraction % (OE= SaO2- ScvO2)than hematocrit
   4. 100 cc oxygenated blood carries 20 cc oxygen
   5. for children: 20 cc/kg LR then 10 cc/kg PRBCs
5. In the immediate post-operative period, causes of bleeding
   1. ineffective local hemostasis
   2. complications of blood transfusion (depletion of platelets)
   3. previously undetected hemostatic defect (GI loss)
   4. consumptive coagulopathy (DIC, trauma, sepsis, fat emboli)
      1. in DIC see thrombocytopenia, positive protamine test for fibrin monomers, low fibrinogen levels, elevated fibrin degradation products (FDP)