Regional and local brain oxygenation during hemorrhagic shock: a prospective experimental study on the effects of small-volume resuscitation with norepinephrine.
BACKGROUND
Patients with uncontrolled hemorrhage may benefit if resuscitation with large amounts of fluids is replaced by a small volume or vasopressor until surgery. Norepinephrine (NE) is commonly used as a vasopressor to control hypotension. The purpose of this study was to compare the effects of hypertonic-hyperoncotic saline starch solution (HHS) either alone or combined with NE on brain tissue oxygen pressure (PbtO2) and brain oxygen saturation (rSO2) in a model of uncontrolled hemorrhage.


METHODS
After approval of the animal investigation committee, 22 anesthetized pigs underwent simulated penetrating liver trauma. At hemodynamic decompensation, animals were randomly assigned to receive HHS (Hyperhaes; 4 mL/kg; n = 8) with normal saline placebo, low-dose NE (low NE; 500 microg, and 1 microg/kg/min; n = 7), or high-dose NE (high NE; 1,000 microg, and 1 microg/kg/min; n = 7). Bleeding was controlled manually 30 minutes after drug administration.


RESULTS
Cerebral perfusion pressure (CePP), PbtO2, and rSO2 decreased with hemorrhage in all groups (baseline vs. decompensation, CePP-HHS, 83 +/- 5 mm Hg vs. 9 +/- 1 mm Hg; low NE, 67 +/- 6 mm Hg vs. 16 +/- 2 mm Hg; high NE, 77 +/- 7 mm Hg vs. 15 +/- 1 mm Hg. PbtO2-HHS, 100% vs. 29%; low NE, 100% vs. 33%; high NE, 100% vs. 27%. rSO2-HHS, 100% vs. 70%; low NE, 100% vs. 76%; high NE, 100% vs. 63%). Therapy with HHS, low NE, and high NE resulted in a comparable increase of CePP, PbtO2, and rSO2, respectively (5 minutes after therapy, CePP-HHS, 29 +/- 3 mm Hg; low NE, 27 +/- 3 mm Hg; high NE, 28 +/- 3 mm Hg. PbtO2-HHS, 207%; low NE, 129%; high NE, 170%. rSO2-HHS, 94%; low NE, 83%; high NE, 87%). Overall survival was six of eight, four of seven, and six of seven, respectively.


CONCLUSIONS
After uncontrolled hemorrhagic shock, addition of different dosages of NE to HHS, compared with HHS alone, showed no beneficial effect on CePP, rSO2, or PbtO2.
Cavus
Erol
E
Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany. e.cavus@t-online.de
Meybohm
Patrick
P
Dörges
Volker
V
Stadlbauer
Karl-Heinz
KH
Wenzel
Volker
V
Weiss
Heiko
H
Scholz
Jens
J
Bein
Berthold
B
D000704:Analysis of Variance; D000818:Animals; D001784:Blood Gas Analysis; D001921:Brain / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology*; D008099:Liver / Q000293:injuries; D009638:Norepinephrine / Q000494:pharmacology*; D010100:Oxygen / Q000378:metabolism*; D010952:Plasma Substitutes / Q000494:pharmacology*; D011446:Prospective Studies; D012151:Resuscitation / Q000379:methods*; D012771:Shock, Hemorrhagic / Q000188:drug therapy* / Q000378:metabolism; D018709:Statistics, Nonparametric; D015996:Survival Rate; D013552:Swine
D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D010100:Oxygen; D009638:Norepinephrine