Spontaneous ventilation:

• Airway noise
• Tracheal tug
• See-saw respiratory pattern

Controlled ventilation:

• It may not be possible to hand ventilate the patient adequately (there may be a leak around the cuff due to a poor seal)
• The patient may have noisy or obstructed breathing
• Poor chest expansion
• High airway pressures
• It just doesn’t ‘feel’ right
• Poor, absent or obstructed looking capnography trace