Noninvasive muscle oxygenation to guide fluid resuscitation after traumatic shock.
BACKGROUND
Three different protocols tested the hypothesis that hind limb muscle tissue O(2) saturation (StO(2)), measured noninvasively with near-infrared spectroscopy (NIRS), is as reliable as invasive systemic oxygenation indices to guide fluid resuscitation.


METHODS
In series 1, swine (n=30) were hemorrhaged, then received either no fluid, a fixed volume of colloid (15 mL/kg), or shed blood plus lactated Ringer's (LR) titrated to MAP >60 mm Hg. In series 2, swine (n=16) received a penetrating femur injury, a 47% to 55% hemorrhage to determine a median lethal dose (LD(50)) then shed blood plus LR titrated to MAP >60 mm Hg. In series 3, swine (n=5) received the femur injury plus LD(50) hemorrhage, and were resuscitated with LR titrated to StO(2) >50%.


RESULTS
In series 1, StO(2) tracked mixed venous O(2) saturation (SvO(2)), but discriminated between 3 survivor groups better than SvO(2), arterial lactate, or arterial base excess. In series 2, StO(2) tracked SvO(2) but discriminated between 2 survivor groups better than SvO(2), arterial lactate, or arterial base excess. In series 3, animals survived to extubation when resuscitated to an StO(2) target.


CONCLUSIONS
Noninvasive muscle StO(2) determined by NIRS was more reliable than invasive oxygenation variables as an index of shock. Because muscle StO(2) can be easily monitored in emergency situations, it may represent an improved method to gauge the severity of shock or the adequacy of fluid resuscitation after trauma.
Crookes
Bruce A
BA
Daughtry Family Department of Surgery, University of Miami School of Medicine, FL 33136, USA.
Cohn
Stephen M
SM
Burton
Elizabeth A
EA
Nelson
Jacob
J
Proctor
Kenneth G
KG
D000818:Animals; D001158:Arteries / Q000378:metabolism; D005260:Female; D005269:Femur / Q000293:injuries; D005440:Fluid Therapy / Q000592:standards; D006614:Hindlimb; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D012151:Resuscitation / Q000592:standards; D012774:Shock, Traumatic / Q000175:diagnosis / Q000628:therapy*; D019265:Spectroscopy, Near-Infrared; D015996:Survival Rate; D013552:Swine
D019344:Lactic Acid; D010100:Oxygen