Final answer:
Patients with high airway resistance, high expiratory flow resistance, and those supported by spontaneous breath modes are all at the greatest risk for auto-PEEP, which leads to breath stacking and increased lung volumes due to insufficient expiratory time.
Step-by-step explanation:
The patients at greatest risk for auto-positive end-expiratory pressure (PEEP) are those who fit into all three categories: those supported by spontaneous breath modes, those with high airway resistance, and those with high expiratory flow resistance. Auto-PEEP can occur when a patient's expiratory time is insufficient to allow the lungs to fully deflate before the next breath, leading to 'breath stacking' and increased lung volumes.
Patients with conditions like pulmonary fibrosis or respiratory distress syndrome have reduced lung compliance and might experience air trapping, hence they might be at risk. Similarly, conditions with high airway or expiratory flow resistance can also contribute to the risk of auto-PEEP, as they can further impede proper exhalation.