Question 2

College Answer

This is not an uncommon question in long-stay ICU patients. Is eating possible? The two parts to be covered are:

(a)        How does a tracheostomy interfere with swallowing?

Normal swallowing requires timing and coordination of many muscles and several cranial nerves, which are under voluntary and involuntary nervous control. The phases are; (1) oral preparatory –mastication and creation of a bolus, (2) oral transit –delivering the bolus to the back of the tongue, soft palate is elevated to allow passage, (3) pharyngeal – is most complex with pharyngeal constriction to create a dynamic pressure gradient, breath-holding, elevation of  arytenoids,  cord  adduction  and  epiglottic  inversion,  (4)  oesophageal  stage  –with coordinated  contraction  and  relaxation  of  oesophageal  sphincters  and  peristaltic  waves carrying the bolus.

A list of therefore could have included: Placement of a tracheostomy -

-           impedes laryngeal elevation

-           impairs hypopharyngeal and laryngeal sensation by desensitisation

-           leads to disuse atrophy of laryngeal and pharyngeal muscles

-           impairs glottic reflex closure

-           reduces subglottic pressure

 (b)      How will you assess her ability to swallow safely?

A tracheostomy cuff does not guarantee prevention of aspiration. Assessment is best achieved by:

- assessment of (1) general condition and (2) specific ability to handle a test swallow.

A breathless and weak patient, who is unwell with sepsis etc., is unable to coordinate swallowing.

- motor movements of the lips face tongue jaw and palate are evaluated for strength, symmetry, speed, accuracy and range of motion for specific nerve deficits. Elevation of the larynx with attempted swallowing should be observed. Strength of cough and timing and fullness of laryngeal excursion give clues to general laryngeal protection.

-test of swallowing and airway protection: this is commonly performed with blue dye mixed with a variety of food consistencies. A bolus of thick liquid is more easily maintained in a bolus and more safely swallowed. After swallowing the tracheostomy is suctioned at intervals to detect leak of dye into the airway. Unfortunately, false negative tests are common (confirmed by video fluoroscopic imaging) so vigilance should be maintained even if the test is passed.

Discussion

A good paper from 1971 discusses this question in some detail.

In summary, the swallowing defects due to tracheostomy are as follows:

• It prevents the larynx from elevating normally
  • thus, hypopharyngeal sphincter fails to open
  • thus, food spills into the larynx
• It desensitises the sensation of the larynx, preventing normal cough in response to aspiration. The effect is likened to stroke-related bulbar dysfunction
• Long periods of being NG-fed result in the deconditioning of muscles involved in swallowing

Assessment of swallowing is a fine art. See this detailed proforma to help speech pathologists. Others are even more extensive.

To summarise,

• Physical assessment:
  • intact cough reflex
  • intact gag reflex
  • adequate laryngeal elevation
  • absence of obvious cranial nerve signs
• Investigations
  • videolaryngoscopy
• Test swallow
  • blue food dye in the swallow
  • sequential tracheal aspirates to demonstrate that no blue dye is in the lung
  • alternatively, barium swallow
• The gold standard is a videofluoroscopic swallowing study, AKA the modified barium swallow.

LITFL have a good page on this (they have a good page on everything).

 

Bonanno, P. C. "Swallowing dysfunction after tracheostomy." Annals of surgery174.1 (1971): 29.

 

Mann, Giselle. MASA, the mann assessment of swallowing ability. Vol. 1. Cengage Learning, 2002.

 

Goldsmith, Tessa. "Evaluation and treatment of swallowing disorders following endotracheal intubation and tracheostomy." International anesthesiology clinics38.3 (2000): 219-242.

 

Prigent, Hélène, et al. "Effect of a tracheostomy speaking valve on breathing–swallowing interaction." Intensive care medicine 38.1 (2012): 85-90.

 

Macht, Madison, et al. "ICU-Acquired Swallowing Disorders." Critical care medicine 41.10 (2013): 2396-2405.