Normal versus supranormal oxygen delivery goals in shock resuscitation: The response is the same

Background. Shock resuscitation is integral to early management of severely injured patients. Our standardized shock resuscitation protocol, developed in 1997 and implemented as a computerized intensive care unit (ICU) bedside decision support tool in 2000, used oxygen delivery index (Do(2)I) greater than or equal to 600 mL/min/m(2) as the intervention endpoint. In a recent publication, Shoemaker et al. refuted positive outcome effect of early supranormal Do(2) (i.e., Do(2)I greater than or equal to 600) resuscitation. In response to and because of ongoing concern for excessive volume loading, we decreased our Do(2)I endpoint from 600 to 500. Our hypothesis was that by decreasing the Do(2)I endpoint, less crystalloid would be administered. We compare resuscitation responses to the protocol with goals of Do(2)I greater than or equal to 600 versus 500 in two patient cohorts. Methods. A standardized protocol was used to direct bedside decisions for resuscitation of patients with major injury (Injury Severity Score > 15), blood loss (greater than or equal to 6 units of packed red blood cells), metabolic stress (base deficit greater than or equal to 6 mEq/L), and no severe brain injury. The protocol logic is to attain and maintain Do(2)I greater than or equal to a specified goal for the first 24 ICU hours using primarily blood and volume loading. Two cohorts were compared: Do(2)I greater than or equal to 500 (18 patients admitted February-August 2001) versus Do(2)I greater than or equal to 600 (18 patients admitted during 2000 age and gender matched with the Do(2)I greater than or equal to 500 group). Data were analyzed using analysis of variance, chi(2), and t tests (p < 0.05). Results: Both groups had similar demographics (age 30 +/- 3 years; 78% men; Injury Severity Score 27 +/- 3), hemodynamics, and severity of shock at start of resuscitation in the ICU. Resuscitation response was Do(2)I increase to greater than or equal to 600 for both cohorts within similar to12 hours. Throughout the 24-hour ICU process, the Do(2)I greater than or equal to 500 cohort received less lactated Ringer's volume than the Do(2)I 2: 600 cohort (total of 8 +/- 1 vs. 12 +/- 2 L; p < 0.05) and tended to receive less blood transfusion (total of 3 -t 1 vs. 5 :L 1 units of packed red blood cells). Conclusion: Shock resuscitation using Do(2)I greater than or equal to 500 was indistinguishable from D021 2: 600 mL/min/m(2). Less volume loading was required to attain and maintain Do(2)I greater than or equal to 500 than 600 using computerized protocol technology to standardize resuscitation during the first 24 ICU hours.