ENT was consulted immediately, direct laryngoscopy revealed Unilateral Vocal cord paralysis. We got a CT soft tissue of neck to evaluate any pathology related to recurrent laryngeal nerve that might explain the vocal cord paralysis. CT was unremarkable for any mass lesion / compressive etiology. Eventually, patient was managed with speech therapy and ENT follow up on discharge.
This patient also got a Pulmonary function test incidentally for evaluation of his restrictive lung disease that showed the following :
This is a classic flow volume loop for vocal cord paralysis (variable extra thoracic obstruction) where the inspiratory loop is flattened. Please compare it to the text book picture below.
1. How common is vocal cord palsy post extubation?
- No one knows, but there are ample number of case reports that we must know about it.
- Unilateral vocal cord paralysis typically manifests as hoarseness immediately after extubation.
- Caused by compression of the anterior branch of the recurrent laryngeal nerve between the ETT cuff and the thyroid cartilage in the subglottic larynx.
- The paralyzed cord becomes fixed in the adducted position.
- Bilateral vocal cord injury is less common, but its clinical manifestations are more severe (eg: extubation failure).
3. What are the risk factors?
- Prolonged intubation (variably defined as ≥36 hours to ≥3 days)
- Traumatic intubation
- Not using a myorelaxant drug during intubation.
- Large ETT (>8 mm in men, >7 mm in women)
- Presence of a nasogastric tube
4. How to treat ?
- Early ENT referral is important in these patients to rule out potentially serious causes such as malignancy.
- Once bad stuff is ruled out, there is no magic treatment for ETT trauma related vocal cord paralysis !!
- Speech therapy is key for functional improvement.
5. Is the damage permanent?
- Usually resolves over days to months. Only time will tell :)
6. Can we prevent it?
- We can definitely try!
- Avoiding the following:
- An oversized ETT
- Overinflated ETT cuff [As a general guideline, cuff pressure should be maintained between 18 and 25mm Hg. Above 18 mmHg to prevent an air leak (air escaping around the ETT cuff) and reduce aspiration around the cuff. Below 25 mmHg to reduce the risk of pressure necrosis]
- Excessive ETT movement
- Prolonged intubation if possible.