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Relationships of Oxygen Uptake and Oxygen Delivery in Respiratory Failure Not Due to the Adult Respiratory Distress Syndrome

1988; Elsevier BV; Volume: 93; Issue: 5 Linguagem: Inglês

10.1378/chest.93.5.1013

1931-3543

Paul Dorinsky, Julie L. Costello, James E. Gadek,

Sepsis Diagnosis and Treatment

Previous studies have suggested that oxygen uptake ( V ˙ o 2 ) 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 V ˙ o 2 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 V ˙ o 2 is dependent on QO2 in both patients with ARDS and non-ARDS respiratory failure. In contrast, regional venous oxygen tension differences varied considerably between the two groups of patients, indicating differences 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 V ˙ o 2 and QO2 is not unique to patients with ARDS and may not predict regional adaptations to critical reductions in substrate availability. Previous studies have suggested that oxygen uptake ( V ˙ o 2 ) 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 V ˙ o 2 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 V ˙ o 2 is dependent on QO2 in both patients with ARDS and non-ARDS respiratory failure. In contrast, regional venous oxygen tension differences varied considerably between the two groups of patients, indicating differences 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 V ˙ o 2 and QO2 is not unique to patients with ARDS and may not predict regional adaptations to critical reductions in substrate availability.