Patient selection
peripheral hypoperfusion
HEMOGLOBINOPATHIES
The inclusion criteria were 1) being 18 years or older, 2) receiving mechanical ventilator support, and 3) undergoing invasive arterial monitoring. The exclusion criteria were 1) requiring high doses of vasopressors (≥1 µg/kg/min norepinephrine or all vasopressors calculated equivalent to this dose); 2) having peripheral hypoperfusion; 3) being hemodynamically unstable; 4) having hemoglobinopathies; 5) being pregnant; 6) having a body mass index greater than 40 kg/m