Final answer:
D. A 50-year patient with respiratory disorder and vital capacity <1 liter
Aquatic therapy is contraindicated for a patient with severe respiratory compromise, as a vital capacity below 1 liter presents a high risk of breathing difficulties or drowning during the therapy session.
Step-by-step explanation:
The patient who would be absolutely contraindicated for an aquatic therapy session with a physical therapist is the 50-year-old patient with a respiratory disorder and vital capacity <1 liter. Aquatic therapy involves exercises in water, typically in a pool, and requires adequate respiratory function to ensure safety.
A vital capacity of less than 1 liter indicates severe respiratory compromise, which can lead to difficulties in breathing, especially while in water, and thus poses a significant risk during aquatic therapy. The risk of drowning or exacerbating respiratory distress is too high to permit safe participation in aquatic therapy for this patient.