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

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 I) > or = 600 mL/min/m as the intervention endpoint. In a recent publication, Shoemaker et al. refuted positive outcome effect of early supranormal Do (i.e., Do I > or = 600) resuscitation. In response to and because of ongoing concern for excessive volume loading, we decreased our Do I endpoint from 600 to 500. Our hypothesis was that by decreasing the Do I endpoint, less crystalloid would be administered. We compare resuscitation responses to the protocol with goals of Do I > or = 600 versus 500 in two patient cohorts.

A standardized protocol was used to direct bedside decisions for resuscitation of patients with major injury (Injury Severity Score > 15), blood loss (> or = 6 units of packed red blood cells), metabolic stress (base deficit > or = 6 mEq/L), and no severe brain injury. The protocol logic is to attain and maintain Do I > or = a specified goal for the first 24 ICU hours using primarily blood and volume loading. Two cohorts were compared: Do I > or = 500 (18 patients admitted February-August 2001) versus Do I > or = 600 (18 patients admitted during 2000 age and gender matched with the Do I > or = 500 group). Data were analyzed using analysis of variance, chi, and t tests (p < 0.05).

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 I increase to > or = 600 for both cohorts within approximately 12 hours. Throughout the 24-hour ICU process, the Do I > or = 500 cohort received less lactated Ringer's volume than the Do I > or = 600 cohort (total of 8 +/- 1 vs. 12 +/- 2 L; p < 0.05) and tended to receive less blood transfusion (total of 3 +/- 1 vs. 5 +/- 1 units of packed red blood cells).

Shock resuscitation using Do I > or = 500 was indistinguishable from Do I > or = 600 mL/min/m. Less volume loading was required to attain and maintain Do I > or = 500 than 600 using computerized protocol technology to standardize resuscitation during the first 24 ICU hours.