Response of critically ill patients to treatment aimed at achieving supranormal oxygen delivery and consumption. Relationship to outcome.
OBJECTIVE
To evaluate the response to therapy aimed at achieving supranormal cardiac and oxygen transport variables (cardiac index [CI] > 4.5 L/min/m2, oxygen delivery [DO2] > 600 ml/min/m2, and oxygen consumption [VO2] > 170 ml/min/m2) in a heterogenous group of critically ill patients and to assess its relationship to outcome.


METHODS
Patients were divided retrospectively into two groups. Group 1 (n = 15) achieved supranormal values for CI, DO2 and VO2 simultaneously during the first 24 h. Group 2 (n = 17) failed to achieve these goals simultaneously at any time point.


METHODS
General intensive care units in a teaching and a district general hospital.


METHODS
Thirty-two patients at risk of developing multiple organ failure were studied prospectively.


METHODS
Patients received volume expansion and then, if necessary, dobutamine (5 to 200 micrograms/kg/min) to increase CI and DO2 until all three goals were achieved simultaneously.


RESULTS
In group 2, target VO2 could never be reached despite the fact that 11 (65 percent) patients achieved target CI and DO2 simultaneously. In this group, lactate levels did not fall and 16 patients died. In contrast, in group 1, attainment of all goals was associated with a significant reduction (p < 0.05) in blood lactate levels, and all but one of these patients survived. The persistently raised lactate levels in group 2 were associated with significantly higher venous oxygen saturation (SvO2) and lower oxygen extraction ratio (OER); in these patients, SvO2 rose and OER fell in response to increases in DO2.


CONCLUSIONS
These results suggest that failure to increase VO2 was related predominantly to an inability of the tissues to extract or utilize oxygen rather than a failure to increase DO2. These findings support the hypothesis that in order to survive a critical illness, patients must achieve a high level of VO2. An inability to do so is reflected in persistently elevated blood lactate levels and an extremely poor prognosis.
Hayes
M A
MA
Department of Anaesthesia, St. Bartholomew's Hospital, London, England.
Yau
E H
EH
Timmins
A C
AC
Hinds
C J
CJ
Watson
D
D
D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy; D003422:Critical Care / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D010102:Oxygen Inhalation Therapy; D012128:Respiratory Distress Syndrome / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012772:Shock, Septic / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy; D016896:Treatment Outcome
D010100:Oxygen