A Patient Breathing 40% O₂ at Sea Level Has a PaO₂

question 68

Multiple Choice

A patient breathing 40% O₂ at sea level has a PaO₂ of 50 mm Hg, a PCO₂ of 30 mm Hg, and a PAO₂ - PaO₂ of 250 mm Hg. When the FiO₂ is raised to 0.7, the PaO₂ rises to only 58 mm Hg. Hypoxemia is primarily due to which of the following?

• A) Hypoventilation
• B) Impaired diffusion
• C) Right-to-left shunt
• D) imbalance

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Definitions:

ABAB Design

Another name for Reversal Design, illustrating the sequence of observational and intervention phases: A (baseline) followed by B (intervention), another A (withdrawal of intervention), and final B (re-introduction of intervention).

ABAB Designs

A type of experimental design used in behavioral research involving sequential phases to compare the effect of a variable.

Multiple-Baseline Designs

Multiple-baseline designs are experimental methods used to demonstrate the effect of an intervention across different settings, behaviors, or individuals by introducing the intervention at different times.

Internal Validity

The extent to which a study can demonstrate that a causal relationship exists between the variables tested, free from the influence of extraneous variables.