Objective: To review the available endpoints of shock resuscitation, including traditional perfusion parameters, oxygen-transport variables, lactate, base deficit (BD), venous oxygen saturation, and gastric mucosal pH, and to discuss the currently accepted methods of assessing successful reversal of oxygen (O2) debt in shock patients.
Human-based studies: Early goal-directed therapy has unequivocally been shown to positively affect outcome in human patients experiencing cardiovascular shock. However, specific endpoints of resuscitation to target in critically ill patients remain controversial. Reliance on traditional endpoints of resuscitation (heart rate [HR], blood pressure [BP]) appears insufficient in detection of ongoing tissue hypoxia in shock states. A multitude of publications exist suggesting that indirect indices of global (lactate, base deficit, mixed/central venous oxygen saturation), regional (gastric intramucosal pH [pHi]) and cellular (transcutaneous oxygen) oxygenation are more successful in outcome prediction and in assessing adequacy of resuscitative efforts in this patient population.
Veterinary-based studies: While there are several large studies evaluating endpoints of resuscitation in experimental canine shock models, this author was unable to find similar research pertaining to small animal veterinary patients. The few articles in which blood lactate is evaluated for prognostic purposes in canine patients are included in this review.
Data sources: Veterinary and human literature review.
Conclusions: Optimization of early resuscitative efforts has proven to have a survival benefit in human shock patients, and major strides have been made in determining which endpoints of resuscitation to target in this patient population. Similar clinical trials designed to evaluate indices of ongoing global and regional tissue hypoxia in small animal veterinary shock patients are warranted.