Fonte: James W Bonz, MD, Emergency Medicine, Yale School of Medicine, New Haven, Connecticut, EUA
Um procedimento cirúrgico das vias aéreas é indicado quando outras formas de intubação endotraqueal falharam e a ventilação está piorando ou não possível. Este é o temido cenário de “não pode entubar, não pode ventilar” e, no cenário de emergência, a cricothyrotomia é o procedimento cirúrgico de escolha.
A cricothytomia é preferida em vez da traqueotomia devido ao menor risco de complicações, à anatomia previsível da membrana cricothiroide e à rapidez comparativa com que o procedimento pode ser realizado — mesmo por praticantes menos experientes. Cricothyrotomia tradicionalmente tem sido feita de forma “aberta”; no entanto, a cricothitomia percutânea usando a técnica padrão seldinger tem sido avançada como uma abordagem mais bem sucedida quando a identificação dos marcos anatômicos relevantes é mais difícil. A técnica de seldinger envolve a introdução de um dispositivo no corpo através do uso de uma agulha introdutor e um fio guia. A agulha é usada para localizar o alvo; um fio-guia é então alimentado através da agulha de parede fina no alvo, agindo como um “espaço reservado” para o dispositivo, que é alimentado sobre o fio guia e para dentro do alvo.
No caso da cricothitomia percutânea, o praticante identifica pela primeira vez a membrana cricothyroide por marcos físicos e faz uma pequena incisão vertical da pele. Uma agulha de 18 bitolas fina (presa a uma seringa) perfura a membrana, e as vias aéreas são identificadas positivamente quando o ar é aspirado na seringa. Um fio-guia é então alimentado através da agulha. Os conjuntos de cricotiretomia padrão incluem um cateter de vias aéreas (semelhante a um tubo de traqueostomia) com um dilatador rígido dentro de seu lúmen. A combinação cateter/dilatador é alimentada no fio guia e o cateter/dilador é colocado dentro das vias aéreas. O dilador e o fio-guia são posteriormente removidos, e o cateter é anexado a um dispositivo de válvula de saco para ventilação.
Percutaneous cricothyrotomy using Seldinger technique is a critical and life saving procedure. It was first described by Melker and is also referred to as “Melker technique.” The decision to place a surgical airway must be made quickly. The procedure itself should be completed in less than a minute. Percutaneous cricothyrotomy with needle and guide wire has been advocated over open cricothyrotomy because the potential complications in an open cricothyrotomy can prove disastrous for the patient.
The benefit of Seldinger technique in performing cricothyrotomy is that the airway is located with a needle, and its access is “held” with the guide wire until the airway catheter is in place. If the cricothyroid membrane is not encountered with the first needle insertion, the location may be re-adjusted and there is less likely to be a life-threatening complication than if the location were misidentified with a scalpel blade. An open cricothyrotomy, by contrast, relies on identification of the cricothyroid membrane and airway by visual inspection after a vertical incision is made with a scalpel. In the event of hemorrhage, visualization can become impossible. Additionally, in obese patients and those with otherwise poor anatomic landmarks, identifying the midline can be a challenge.
Although there are a variety of commercially available percutaneous cricothyrotomy kits, this technique can be done easily with supplies commonly found in the emergency department. There are many procedures that rely on Seldinger technique. A central venous catheter kit could be utilized, for example. It should be noted that other versions of this technique have been described. Some feel that identification of the airway using a needle without the subsequent use of Seldinger technique is the best strategy, combining elements of open cricothyrotomy and needle identification of the airway.
Cricothyrotomy is a surgical airway procedure indicated when other forms of endotracheal intubation have failed and patient ventilation is declining or not possible.
The two forms of this procedure are open or surgical cricothyrotomy – discussed in a different video – and percutaneous cricothyrotomy, which will be discussed here. The latter is the method of choice for many practitioners especially when identification of the relevant anatomic landmarks is more difficult, such as in the patients with short neck and excessive soft tissue.
In this presentation, we will outline how to conduct the percutaneous cricothyrotomy procedure using a pre-packaged kit and when kit is not available.
Start by gathering the necessary supplies for the procedure including: chlorhexadine, a bag valve mask device, suction and oxygen supply equipment, and the pre-packaged percutaneous cricothyrotomy kit. A standard pre-packaged kit should include: a 18 gauge introducer needle, a 5 milliliter syringe, scalpel, guide wire, a dilator, an airway catheter and a neck-tie.
After opening the kit, attach the introducer needle to the syringe, make sure that the catheter and dilator are assembled, and lay out the guidewire and scalpel for easy access. The patient in this situation has likely undergone attempted endotracheal intubation and should already be lying supine. Stand at the patient’s head, extend the neck (2.4.2) and palpate to locate the cricothyroid membrane. This membrane is located below the laryngeal prominence — the “Adam’s Apple”. After locating the membrane, grab the paratracheal structures and move them around. They will move as a unit and create a depression. The needle insertion landmark is in the midline of this depression. If time allows, the area should be cleaned with chlorhexadine, and ideally, the exam gloves should be traded for sterile gloves. However, as with all emergent procedures, true sterile technique may be sacrificed for rapidity.
Make a small 5-millimeter vertical incision with the scalpel at the identified midline. Then, advance the introducer needle at a 45° angle into the incision and through the cricothyroid membrane toward the patient’s feet. Withdraw on the plunger while advancing the needle. When the needle enters into the airway, you will be able to aspirate air easily. Next, brace your hand against the patient’s neck and remove the syringe from the needle. Be sure to keep the needle opening within the air filled lumen.
Now, advance the guidewire through the needle approximately 15 centimeters to assure the wire is well within the airway. Then, remove the needle, keeping the guidewire in place. Next, thread the catheter-dilator assembly over the wire and push it through the patient’s skin. While doing so, anatomically orient the device with the airway such the curve of the catheter matches the curve needed from its entry point into the trachea. Keep pushing until the catheter is fully in place — that is till the plastic flange is against the patient’s neck. Next, remove the dilator and the wire from the assembly and attach the catheter to the bag-valve manual resuscitator. Confirm correct placement by auscultating for breath sounds, and monitoring the end tidal CO2 — the normal range for which is 35-45 mmHg.
Finally, secure the airway catheter with appropriate necktie.
Now let’s review how to conduct the percutaneous cricothyrotomy procedure without a kit, which is not ideal, but may be the most preferable option in an emergency situation.
For supplies, open the central venous catheter tray and remove the following items : a 5-milliliter syringe, an introducer needle, a guidewire, and a scalpel. In addition, obtain a tracheostomy tube .
Attach the introducer needle to the empty 5-milliliter syringe. Then, prepare the guidewire by retracting it in its sheath and straightening out the J tip. Locate the cricothyroid membrane by palpating as shown previously and prep the neck with chlorhexadine if time allows. Grab the laryngeal structures as a unit to be certain that the midline is identified. Next, while applying gentle pressure to the plunger, advance the introducer needle at a 45° angle in caudal direction. Once the needle tip reaches the trachea, air can be easily aspirated into the syringe. Now, with your non-dominant hand, hold the needle steady and remove the syringe with your dominant hand. Then advance the guide wire 15 centimeters through the introducer needle. Next, with a number 11-scalpel blade make a horizontal incision at the level of the needle — approximately 2 centimeter in length and 2 cm deep –, cutting through the skin and cricothyroid membrane. Now, remove the needle and leave the guidewire in place and load the tracheostomy tube onto the guidewire.
Next, to dilate the incision open, retract the scalpel blade and advance the handle of the scalpel through the incision. With the handle is firmly inside the incision, rotate it by 90° so that it is oriented parallel with the patient’s neck and perpendicular to the horizontal incision. This will hold the aperture open and allow for easier passage of the tracheostomy tube. Advance the tube over the guidewire and through the opening created by the scalpel handle. This will assure that the tube follows the correct tract into the airway. After the tube is in position, remove the guide wire, attach the tube to the ventilator device and secure it in place with neckties.
Cricothyrotomy is a critical and life saving procedure. The decision to place a surgical airway must be made quickly, and the procedure itself should be completed in less than a minute. The procedure shown in this video on percutaneous cricothyrotomy using the Seldinger technique has been advocated over open cricothyrotomy, because of the potential for bleeding with open cricothyrotomy.
A major advantage of using a needle to locate the airway is that if the cricothyroid membrane is not encountered with the first needle insertion, the location may be re-adjusted and there is less likely to be a life threatening complication.
On the contrary, the open cricothyrotomy procedure relies on identification of the cricothyroid membrane and airway by visual inspection after a vertical incision is made with a scalpel. If there is a hemorrhage, visualization can become impossible. Furthermore, in the obese and in those with otherwise poor anatomic landmarks, identifying midline can be a challenge.
You have just watched a JoVE video demonstrating the percutaneous cricothyrotomy procedure, with and without a pre-packaged kit. As always, thanks for watching!
