Passy-Muir Valve

This is very simply a one-way valve which is fitted on to the end of a cuff-down tracheostomy tube, in order to allow speech. This item has its origin detailed, and its virtues extolled, in a comprehensive tribute website which is owned by the manufacturer of the valve.

Anatomy of the item

This thing is a simple one way valve.

the passy-muir valve

One end plugs into the patient's tracheostomy via a standard connector; the other end can plug into a ventilator, or remain open.

Details of function

Having one of these on a tracheostomy enables the wearer to speak. Instead of exhaling through the tracheostomy, the closed valve causes air to travel around the tracheal tube and into the vocal cords.

The fact that the valve remains closed until inspiration begins is helpful, because it keeps a column of air in the trachea, which is under positive pressure while the lungs recoil in expiration. This prevents the aspiration of upper airway secretions and swallowed food or liquids.

Indications for use

  • Enabling speech in a tracheostomy patient
  • Enabling forceful expectoration of upper airway secretions in a tracheostomy patient
  • Decreasing the risk of aspiration in a patient with a cuff-down tracheostomy

This device prevents the need to finger-block one's tracheostomy each time one is inclined to speak or spit.

Contraindications for use

  • Inflated (or foam filled) tracheostomy cuff (you wont be able to exhale)
  • Absence of a cuff leak with tracheostomy cuff deflated (you wont be able to exhale)
  • Thick uncontrolled tracheal secretions (you will clog the valve)
  • Thick uncontrolled oral secretions (you need to swallow those, or they will get inhaled)
  • Severe respiratory weakness (you will not be able to overcome the valve resistance to inspiration)
  • Unconsciousness (You cant deflate the cuff in these people)
  • Gas trapping with autoPEEP (the valve will increase PEEP)

Methods of use/insertion

Pretty simple. With the tracheostomy cuff deflated, one attaches the appropriate end of this valve.

Safety features

The standard connectors make it impossible to reverse the valve (which would have ridiculous consequences)

Complications of use

  • The valve may block
  • If the upper airway fails, you wont be able to exhale
  • A good cough can dislodge the valve, sending it across the room
  • Work of breathing may increase
  • A small amount of apparatus dead space is added

References

A detailed autopsy of these devices can be found in the 5th edition of "Understanding Anaesthesia Equipment" By Dorsch and Dorsch. Section III, chapter 20. This chapter seems to be available for free.

Another outstanding resource, which I have shamelessly plundered, can be found online - in an online medical library belonging to the Sultan Qaboos University, in the Sultanate of Oman; therein I have discovered a treasure of anaesthetic and critical care literature.

Russell, Walter John, and T. S. Strong. "Dimensions of double-lumen tracheobronchial tubes." Anaesthesia and intensive care 31.1 (2003): 50-53.

Hannallah MS, Benumof JL, Ruttimann E. The relationship between left mainstem bronchial diameter and patient size. J Cardiothor Vasc Anesth 1995; 9:119-121.

Dyer RA, Heijke SAM, Russell WJ, Bloch MB, James MF. Can insertion length for a double-lumen endobronchial tube be predicted? Anaesth Intensive Care 2000; 28:666-668.

Hampton T, Armstrong S, Russell WJ. Estimating the diameter of the left main bronchus. Anaesth Intensive Care 2000; 28:540-542.

International Standards Organization. Tracheobronchial tubes—recommendations for size designation and labeling (ISO/TS 16628). Geneva, Switzerland: Author, 2003. - warining, the ISO make you pay for this!

Brodsky, J. B. "Lung separation and the difficult airway." British journal of anaesthesia 103.suppl 1 (2009): i66-i75.

Cheong, K. F., and K. F. Koh. "Placement of left-sided double-lumen endobronchial tubes: comparison of clinical and fibreoptic-guided placement."British journal of anaesthesia 82.6 (1999): 920-921.

CARLENS, Eric. "A new flexible double-lumen catheter for bronchospirometry."The Journal of thoracic surgery 18.5 (1949): 742.

Brodsky, J. B., and H. J. M. Lemmens. "The history of anesthesia for thoracic surgery." Minerva anestesiologica 73.10 (2007): 513.