Surgery Generally accepted indications for mechanical ventilatory support include A PaO2 of less than 70 kPa and PaCO2 of greater than 50 kPa while breathing room air B Alveolar-arterial oxygen tension difference of 150 kPa while breathing 100% O2 C Vital capacity of 40-60 mL/kg D Respiratory rate greater than 35 breaths/min 💡 Explanation Generally accepted indications for mechanical ventilatory support include ✓ Correct Answer: D. Respiratory rate greater than 35 breaths/min