Relationships of oxygen uptake and oxygen delivery in respiratory failure not due to the adult respiratory distress syndrome
Dorinsky, P.M.; Costello, J.L.; Gadek, J.E.
Chest 93(5): 1013-1019
ISSN/ISBN: 0012-3692 PMID: 3282813 DOI: 10.1016/0883-9441(88)90137-2
Previous studies have suggested that oxygen uptake ($D+VO2) may be dependent on oxygen delivery (QO2) at most levels of QO2 in patients with the adult respiratory distress syndrome (ARDS); however, the adequacy of substrate delivery in patients with non-ARDS respiratory failure is unclear. The purpose of the present study was to examine the relationship between .ovrhdot.VO2 and QO2 in a group of critically ill patients (n = 10) with non-ARDS respiratory failure (ie, cardiac pulmonary edema, chronic obstructive pulmonary disease [COPD], or pneumonia). For comparison, these relationships were also examined in a group of patients (n = 6) with ARDS. The data indicate that .ovrhdot.VO2 is dependent on QO2 in both patients with ARDS and non-ARDS respiratory failure. In contrast, regional venuos oxygen tension differences varied considerably between the two groups of patients, indicating difference in local adaptations to critical reductions in QO2. Finally, over a similar range of QO2, oxygen extraction was greater in patients with ARDS compared to patients with non-ARDS respiratory failure (r = -0.67 and slope = -0.62 vs r = -0.45 and slope = -0.35; p < 0.05). These data suggest that a linear relationship between .ovrhdot.VO2 and QO2 is not unique to patients with ARDS and may not predict regional adaptations to critical reductions in substrate availability.