Fonte: James W Bonz, MD, Medicina d’urgenza, Yale School of Medicine, New Haven, Connecticut, USA
La cricotirotomia aperta è una procedura chirurgica emergente. Viene eseguito per stabilire un accesso alle vie aeree mediante il passaggio di un tubo attraverso un’incisione nella membrana cricotiroidea. Questa è una procedura di scelta nel temuto scenario “non può intubare, non può ventilare” – quando tutte le altre forme di intubazione endotracheale hanno fallito e la ventilazione spontanea sta peggiorando o è diventata impossibile.
L’accesso alle vie aeree è stabilito tramite il tubo tracheostomico. Il tubo tracheostomico è costituito da tre parti: una cannula esterna (o il tubo tracheostomico stesso), una cannula interna e un otturatore. Durante la procedura, l’otturatore viene posizionato all’interno del tubo tracheostomico per guidare l’inserimento, mentre la cannula interna viene rimossa. L’estremità distale dell’otturatore è arrotondata e sporge attraverso l’estremità del tubo tracheostomico, consentendo al praticante di guidare facilmente il tubo in posizione senza che venga catturato sulle strutture circostanti. Inoltre, l’otturatore impedisce l’intasamento del tubo con il tessuto o i fluidi durante un inserimento. Una volta posizionato il tubo, l’otturatore viene rimosso e la cannula interna viene posizionata all’interno del tubo tracheostomico. In alternativa, la procedura può essere eseguita utilizzando il tubo endotracheale modificato, che sarà dimostrato in questo video.
La cricotirotomia è associata a complicazioni significative e viene eseguita solo quando le misure meno invasive hanno fallito. Tuttavia, è preferito alla tracheotomia (una procedura in cui viene creata un’apertura tra due anelli tracheali), a causa del minor rischio di complicanze associate, della relativa rapidità con cui può essere eseguita e dell’anatomia prevedibile della regione.
La giovane età è considerata una controindicazione alla cricotirotomia aperta, poiché questa procedura è associata ad un aumentato rischio di sviluppare stenosi sottoglottica nei bambini. Tuttavia, c’è disaccordo tra gli esperti su quale età questa procedura diventa accettabile. Le opinioni variano dai 5 anni ai 12 anni di età, e molti considerano questa una controindicazione relativa. Nei bambini piccoli, la tracheotomia è preferita e i pazienti possono essere temporizzato con ventilazione a getto transtracheale attraverso una cricotirotomia ad ago abbastanza a lungo da eseguire questa procedura più coinvolta. Altre controindicazioni includono laringe fratturata o gravi lesioni alla cartilagine cricoide.
A surgical cricothyrotomy is truly an emergency procedure. The procedure itself is straightforward and uncomplicated. Surgical cricothyrotomy is a lifesaving procedure in a patient who would otherwise suffer great morbidity or death from prolonged hypoxia.
Complications from a failed cricothyrotomy can be disastrous, as the loss of airway is loss of life. Most significant complications arise when an artery is lacerated, and the bleeding obscures the surgical field. The superior thyroid arteries run laterally on both sides of the midline and anastomose superficial to the inferior portion of the laryngeal prominence. With anatomic variance, it is not all that infrequent that these vessels may be encountered in the superior portion of the cricothyroid membrane, increasing the risk of laceration during the procedure.
Misplacement of the tracheostomy tube might occur even if the field is not obscured. The tube can be placed in the soft tissue when the opening is not well stabilized with the tracheal hook, or if the Trousseau dilator is not positioned within the incision in the cricothyroid membrane. Several seconds may pass before the complication is recognized, increasing the likelihood that each delivered breath distorts the recognizable anatomy. Therefore, a successful cricothyrotomy requires good knowledge of the surface anatomy, dexterity, and confidence.
Open cricothyrotomy is an emergent surgical procedure of choice in the feared “can’t intubate, can’t ventilate” scenario, which means that all other forms of endotracheal intubation have failed and the spontaneous ventilation is worsening or becoming impossible. It is performed to establish an airway access by passage of a tube through an incision in the cricothyroid membrane, which is located between the thyroid and the cricoid cartilage.
In this presentation, we will review the method for open cricothyrotomy, which includes the prepping steps and the technique for tube insertion. Following that, we will review the contraindications and complications associated with this emergency medicine procedure.
Start by positioning the patient supine with the neck extended. Next, gather all the necessary supplies. This includes: chlorhexidine, number-11 scalpel, tracheal hook, Trousseau dilator, 10cc syringe for inflating the cuff, and a tracheostomy tube.
This tube consists of an outer cannula, which is the tracheostomy tube itself, an inner cannula, and an obturator. Note that the distal end of the obturator is rounded and when it is placed inside the tube the distal tip protrudes through the open end. This allows, one, easy insertion of the tube into place without it being caught in the neighboring structures, and two, prevention of tube clogging with the surrounding tissue or fluids. If the tracheostomy tube is not available, one can use a modified endotracheal tube. To prepare this, remove the Bag Valve Mask adapter at the distal end. Next, cut the tube just distal to the site where the cuff insufflator would enter. Then reattach the adapter.
If the situation calls for local anesthesia such as when rapid sequence intubation medications have not been administrated, and the patient is awake and alert, then gather 5cc syringe with a 25G needle and 1% lidocaine with epinephrine.
If full sterile technique is observed then one should also have sterile towels, facemask, bonnet, sterile gown and sterile gloves. As with all truly emergent procedures, complete sterile technique is optional based on the time pressure of the situation.
Now let’s review the procedural steps. Clean the anterior neck with chlorhexidine by vigorous scrubbing. Full barrier precautions should be undertaken if clinically possible. This includes donning a mask, bonnet, sterile gown and gloves. To optimize the access to the site, stand on the patient’s side that matches your dominant hand, which in this case is “left” , and place sterile towels around the cleaned site to create a complete sterile field.
To locate the insertion site, first palpate the laryngeal prominence or the “Adam’s Apple”, and then move your fingers inferiorly into the depression below to find the cricothyroid membrane. If the palpation is difficult due to body habitus or pathology, the location of the cricothyroid membrane may be estimated as being four fingerbreadths above the sternal notch.
If the patient is awake, administer local anesthesia by inserting the 25-gauge needle just into the skin and creating a wheal in the midline of the expected cricothyroid membrane location. Extend the wheal by 3 cm in both superior and inferior directions.
To start, using the number 11-scalpel, make a 3-5 cm vertical incision in the midline through the skin and subcutaneous tissues. Next, with your non-dominant finger, attempt to feel the cricothyroid membrane through the incision, and then extend the incision superiorly or inferiorly to fully expose the cricothyroid membrane. Now make a 1cm horizontal incision across the cricothyroid membrane at its inferior aspect.
Next, take the tracheal hook and pull the superior portion of the incision upwards. Then using your non-dominant hand, insert the Trousseau dilator through the opening in the cricothyroid membrane, placing the bills on the superior and inferior portions of the incision. Note that the dilator handle would be on the same side as yours. Next, open the bills and rotate the handle to 90° so that it is vertical in relation to the patient. Notice that the dilator bills are now spreading away from the midline. Now, with your dominant hand place the tracheostomy tube with the obturator through the cricothyroid membrane…and remove the Trousseau dilator. Once the tube is in place, remove the obturator, insert the inner cannula of the tube and inflate the cuff using a 10 cc syringe. Next, attach a bag valve unit and ventilate the patient. Lastly, secure the tube in place using the neckties.
If using a modified endotracheal tube, the procedure is the similar. Following incision, place the tube through the cricothyroid membrane…remove the dilator…inflate the cuff… attach the bag valve unit…and secure the tube in place with an endotracheal tube holder.
“Young age is considered a contraindication to open cricothyrotomy as this procedure is associated with an increased risk of developing subglottic stenosis in children. The alternative is temporizing with transtracheal jet ventilation through a needle cricothyrotomy for long enough to perform the more involved tracheotomy procedure. Other contraindications include fractured larynx or severe injury to the cricoid cartilage.”
“Most significant complications related to this procedure arise when an artery is lacerated, and the bleeding obscures surgical field. Note that the superior thyroid arteries run laterally on both sides of the midline, and anastomose superficial to the inferior portion of the laryngeal prominence.”
“With anatomic variance, it is not all that infrequent that these vessels may be encountered in the superior portion of the cricothyroid membrane, increasing the risk of laceration during the procedure.”
“Misplacement of the tracheostomy tube might occur even if the field is not obscured. The tube can be placed in the soft tissue when the opening is not well stabilized with the tracheal hook, or if the Trousseau dilator is not positioned within the incision in the cricothyroid membrane. Several seconds may pass before the complication is recognized, increasing the likelihood that each delivered breath distorts the recognizable anatomy.”
You’ve just watched JoVE’s illustration of surgical or open cricothyrotomy. This is a lifesaving emergency procedure, but the complications from a failed cricothyrotomy can be disastrous, as loss of airway is loss of life. Although the steps are straightforward and uncomplicated, a successful procedure requires good knowledge of the surface anatomy, dexterity, and confidence. As always, thanks for watching!
