Mini-tracheostomy

Inserting a mini-tracheostomy
Minitracheostomy (cricothyroidotomy) is for the treatment or prevention of sputum retention after thoracotomy, laparotomy or neurological insult. It is an alternative to naso-laryngeal suction or regular flexible bronchoscopy.

Timing
It is better to insert it before the patient is distressed and agitated with dropping oxygen saturations. Move on clinical grounds rather than waiting for radiological changes which will follow the clinical by about 24 hours. If the patient is severely hypoxic and non-cooperative it may be wiser to intubate, ventilate and opt for an early tracheostomy rather than a minitrach.

The risk of sputum can be predicted on the basis of:


 * Smoking within 6 m of surgery
 * Ischaemic heart disease
 * COPD
 * Failure of regional analgesia
 * Recurrent laryngeal or phrenic nerve injury are also risk factors

In the presence of one of these risk factors a prophylactic minitrach inserted in recovery will reduce the incidence of predictable sputum retention.

Preparation
No sedation is usually needed as the patient is likely to be hypoxic and sedation is contra-indicated.

Minitrach insertion is a clean rather than sterile.

An assistant is virtually mandatory to hold the head and help with tying in the device and administering suction.

Make sure all the necessary items are present before you start as you may only get one clear chance to get it right.


 * Local anaesthetic: Lignocaine 1% with Adrenaline (the Adrenaline is to reduce bleeding in this very vascular part of the body). Marcaine is slower to act.
 * Suction – number 10 cannula
 * Minitrach kit
 * A mosquito forceps is useful particularly in elderly men with calcified crico-thyroid membrane.

Set out the kit in order where you can pick the components up with one hand while keeping the introducer needle steady.


 * Knife
 * Modified Tuohy needle with syringe: attach syringe and make sure needle is patent by injecting air. Some people put saline in it to see air bubble form trachea.
 * Guidewire – I remove it from the sheath so that I can manipulate it easily with one hand
 * Dilator
 * Introducer/minitrach apparatus- make sure the device can slip off the introducer easily.
 * Tapes

Positioning patient
Have the patient slightly inclined head up in the bed

Place the pillow under the shoulders with the head stretched over the back of the pillow. This places the trachea on a stretch keeping it in the midline and reducing lateral deviation. Hugo Matthews (who developed the device) encouraged us to stand at the head of the bed like a rigid bronchoscopy to keep it all in line.

The oxygen tubing will be in your way. Put the mask on upside down - it is uncomfortable for the patient but it is only for a minute or two.

Procedure
Find the thyroid cartilage – always easier on a male than a female - and the cricoid just below it. If in doubt it is safer to go low into the trachea than high above the cords. This does run the risk of injuring the isthmus of the thyroid (usually not too much of a problem if it is the guidewire and dilator as opposed to the knife). The device is designed to penetrate the crico-thyroid membrane in such a way that the tip does not angle forward and irritate the anterior tracheal wall. If placed into the trachea it will angle forward. This is a theoretical problem if in place for a protracted period.

Fix the cartilage between two fingers and keep them in that position till the device has been inserted.

Inject some local anaesthetic under the skin in the line of the vertical incision. Use this opportunity to pass the needle through the membrane to determine if you are in the right place (the patient will cough++) and to inject some local into the trachea and deeper tissues.

Make a vertical incision in the skin – long enough so there is no resistance at the skin level which will interfere with your feel of the trachea. The partially sheathed knife is designed to cut through skin, fat and crico-thyroid membrane (as in the dissection technique) but this is not usually necessary with the Seldinger technique.

Insert the Tuohy needle (with syringe attached) through the skin incision at right angle to the anterior wall of the trachea. There is often a tendency to angle too high in the direction of the larynx. You will feel a “pop” as you go through the anterior wall.

Keeping the needle still, aspirate air to ensure you are in trachea. If you have gone tangentially down the tracheal wall you can block the needle with a sliver of cartilage. Remove the needle, test again with   the syringe, and replace needle in trachea. Do not proceed unless you are sure you are in the trachea with free aspiration of air. If you are unsure, it may be best to formally dissect down to the membrane,     incise it, dilate it with the mosquito forceps and then pass the introducer through the hole you have made.

Remove the syringe but keep one hand on the needle in situ.

Pass the guidewire (flexible end first) down the needle into the trachea. It usually helps to angle the needle down in the direction of the carina. It should not be forced – there are no points for passing it through a pneumonectomy stump!

Pass the dilator over the wire – again angling it down rather than up to the larynx. Make sure you do not dislodge the guidewire at any stage. The dilator can be passed in and out a few times to achieve good dilation. The dilator is not as wide as it ought to be (as you will discover when you insert the device).

Pass the introducer/minitrach assembly over the guidewire. The introducer will pass easily into the trachea but the minitrach will get caught on the crico-thyroid membrane. Do not try to pass it off the introducer but rather pass it and the introducer together. A slight twist and gentle pressure will aid this step.

Once satisfied the device is in the trachea, remove the introducer. The cap should be pointing inferiorly.

Keeping one hand on the minitrach pass a tape through the loop on each side of the  minitrach (as for a tracheostomy – double the tape so there is one long and one short tail, pass the doubled tape through the loop on the device and bring the two tails through the loop you have created, pass the long one from each side round the back of the neck and tie to the short end one on each side)

Aspirate the minitrach - if the cannula does not pass easily it is probable that the position is not satisfactory. A Chest X-ray will usually confirm the position.

If there is bleeding it will usually be controlled by the pressure of the minitrach. Finger pressure may be needed to supplement the tamponading effect of the tube itself.

Make sure the cap is on the minitrach and that the patient is receiving humidified oxygen. Leaving the cap off allows non-humidified air to be entrained causing caking of secretions.

Followup
The patient should have immediate physiotherapy with suction of the minitrach. This is a good opportunity to obtain a trap sputum specimen prior to starting the antibiotics which will almost routinely be started at this time.

Thereafter it should routinely be aspirated twice a day and at other times when required (particularly with regular physiotherapy).

Removal
Once the physiotherapist is convinced the patient can cough past the minitrach regularly the device can be removed. It is best removed early in the day so that it can be re-inserted during working hours if required.

The incision can be covered with a standard waterproof dressing.

Additional Resources

 * Mc Manus, Kieran, Mini-tracheostomy, How do I do it menu.