Maintaining survivors' values of left ventricular power output during shock resuscitation: a prospective pilot study.

OBJECTIVE: Maintaining left ventricular power output (LVP) > 320 mm Hg x L/min/m2 during resuscitation has been retrospectively associated with faster resolution of acidosis and survival after posttraumatic shock. The purpose of this prospective study was to evaluate the effects of maintaining LVP above this threshold during resuscitation on base deficit clearance, organ failure, and survival.

METHODS: This was a study of a consecutive series of critically injured patients (PWR) monitored with a pulmonary artery catheter during initial resuscitation. LVP, calculated as cardiac index-(mean arterial pressure-central venous pressure), was maintained >320 mm Hg x L/min/m2 via a predefined protocol by using ventricular pressure-volume diagrams. Outcome was assessed by base deficit clearance (<6 mEq/L) in <24 hours, lowest base deficit in the first 24 hours after admission (24-hr base deficit), organ dysfunctions/patient, and survival. Results were compared with 39 control patients (OXY) with identical enrollment criteria from a previous prospective study who were resuscitated based on oxygen transport criteria.

RESULTS: Twenty patients were studied over a 6-month period. Mean LVP during resuscitation in the PWR group was 360 +/- 100 mm Hg x L/min/m2. Admission base deficit was similar between the two groups (PWR 11 +/- 4.2 vs. OXY 11 +/- 5.8 mEq/L;p = 0.66). More PWR patients cleared base deficit in < 24 hours than OXY patients (16 of 20 vs. 17 of 39, p = 0.009, Fisher's exact test), and the PWR patients had a significantly lower 24-hr base deficit (3.9 +/- 3.7 vs. 7.1 +/- 4.6 mEq/L, p = 0.01). Organ dysfunction rate was lower in the PWR group (2.1 +/- 1.5 vs. 3.2 +/- 1.4 organ dysfunctions/patient, p = 0.007). Survival in the PWR group was 15 of 20, versus 21 of 39 in the OXY group (p = 0.10).

CONCLUSION: Prospectively maintaining LVP above 320 mm Hg x L/min/m2 during resuscitation is an achievable goal. It is associated with improved base deficit clearance and a lower rate of organ dysfunction after resuscitation from traumatic shock.