If there are no physical findings suggesting tension pneumothorax, and if ventilation-related causes of hypotension are a possible etiology, pending a portable chest x-ray, the patient may be disconnected from the ventilator and gently bagged manually at 2 to 3 breaths / minute with 100% oxygen while fluids are infused (eg, 500 to 1000 mL of 0.9% saline in adults, 20 mL / kg in children).