Relationship of mortality to increasing oxygen delivery in patients > or = 50 years of age: a prospective, randomized trial.

OBJECTIVE

To investigate the relationship of mortality to early resuscitation using two levels of oxygen delivery (DO2) in critically ill surgical patients > or =50 yrs of age who were stratified into groups: age < or =75 yrs (age 50 to 75 yrs group); and age >75 yrs (age >75 yrs group).

DESIGN

A prospective, randomized trial, continued from a previous project.

SETTING

Surgical intensive care unit, university affiliated.

PATIENTS

Consecutive patients, >50 yrs of age, unable to generate a DO2 of > or =600 mL/min/m2 with fluid resuscitation alone, with a diagnosis of systemic inflammatory response syndrome, sepsis, severe sepsis, septic shock, and/or acute respiratory distress syndrome.

INTERVENTIONS

During the first 24 hrs of resuscitation, patients were randomized to receive fluids, blood transfusions, and vasoactive agents in order to achieve DO2 treatment goals of > or =600 mL/ min/m2 in the protocol group and 450 to 550 mL/min/m2 in the control group.

MEASUREMENTS AND MAIN RESULTS

One hundred five patients completed the study. In patients aged 50 to 75 yrs, the mortality rate was 21% (9/43) in the protocol group and 52% (12/23) in the control group (p=.01, 95% confidence interval of -58% to -4%). In patients >75 yrs of age, the mortality rate was 57% (12/21) in the protocol group and 61% (11/18) in the control group. Oxygen extraction ratios (O2ER) and oxygen consumption values were significantly (p=.02) lower in the age >75 yrs group compared with the age 50 to 75 yrs group.

CONCLUSIONS

Patients 50 to 75 yrs of age receiving a DO2 of > or =600 mL/min/m2 demonstrated a statistically significant (p=.01) improved survival rate over patients in the control group. Patients >75 yrs of age demonstrated no benefit from attempts to increase DO2 to >600 mL/min/m2, and they may have been overtreated as reflected by the lower O2ER values in this age group. Treating to an O2ER that reflects a balance between oxygen consumption and DO2 may be an alternative goal that allows individual titration.