Overview
Definition:
Emergency Front-of-Neck Access (EFONA) refers to a set of surgical techniques employed to establish an emergency airway when less invasive methods of airway management, such as endotracheal intubation or bag-valve-mask ventilation, have failed or are not immediately feasible
The scalpel-bougie-tube technique is a rapid, surgical approach to achieving a secure airway in life-threatening situations
It involves incising the cricothyroid membrane, introducing a bougie to guide a small endotracheal tube into the trachea
This method is a last resort for securing the airway in cases of failed intubation (Can't Intubate, Can't Oxygenate - CICO scenario).
Epidemiology:
The incidence of situations requiring emergency front-of-neck access is relatively low but critical
It is estimated to occur in 0.1% to 1% of all intubation attempts
Factors contributing to the need for EFONA include severe facial trauma, upper airway obstruction from foreign bodies or edema, anatomical distortion, and in rare instances, failed endotracheal intubation attempts in critically ill patients
Studies indicate a higher incidence in emergency departments and pre-hospital settings.
Clinical Significance:
EFONA is of paramount clinical importance as it represents the final pathway to providing oxygenation and ventilation in a life-or-death scenario where conventional airway management has failed
Failure to establish an airway in a CICO situation leads to rapid and irreversible hypoxic brain injury and death
Proficiency in EFONA techniques, particularly the scalpel-bougie-tube method, can significantly improve patient survival rates and reduce morbidity associated with prolonged hypoxia
It is a critical skill for surgeons, emergency physicians, and anesthesiologists.
Indications
Absolute Indications:
Absolute indications for emergency front-of-neck access are limited to the "Can't Intubate, Can't Oxygenate" (CICO) scenario
This includes failed attempts at direct laryngoscopy and intubation, failure to maintain oxygen saturation above 90% despite adequate ventilation attempts with a bag-valve-mask, and the inability to insert a supraglottic airway device
Severe maxillofacial trauma compromising the airway and acute upper airway obstruction (e.g., anaphylaxis with laryngeal edema, foreign body) are also strong indications if less invasive methods are not viable.
Relative Indications:
Relative indications might include inability to visualize the vocal cords (Grade III or IV laryngoscopy views) after multiple attempts, need for prolonged ventilation when endotracheal intubation is not possible or contraindicated (e.g., severe cervical spine injury with difficult intubation), and in patients with suspected cervical spine injury where airway control is paramount but intubation is challenging.
Contraindications:
There are virtually no absolute contraindications to emergency front-of-neck access in a true CICO situation, as the risk of death from hypoxia outweighs any potential risks of the procedure
However, relative contraindications may include a healthy trachea that can be intubated readily, a completely transected trachea, or severe coagulopathy where bleeding might obscure the anatomy
In pediatric patients, needle cricothyrotomy is often preferred over surgical cricothyrotomy due to the smaller anatomical structures and risk of damage to the cricoid cartilage, which is the narrowest part of the pediatric airway.
Scalpel Bougie Tube Technique
Procedure Overview:
The scalpel-bougie-tube technique is a rapid surgical airway procedure designed for use in CICO scenarios
It prioritizes speed and effectiveness
The steps generally involve palpating the cricothyroid membrane, making a stab incision through the skin and membrane, inserting a bougie into the trachea, and then threading a small endotracheal tube (commonly 6.0 mm ID) over the bougie into the trachea
The bougie acts as a reliable guide to ensure correct placement of the tube.
Anatomical Landmarks:
Accurate identification of anatomical landmarks is crucial
The thyroid cartilage (Adam's apple) is palpated, and the finger slides inferiorly into the depression formed by the cricoid cartilage
The cricothyroid membrane lies as a soft, palpable depression between the inferior border of the thyroid cartilage and the superior border of the cricoid cartilage
This membrane is the target for incision.
Step By Step Guide:
1
**Patient Positioning:** Supine position with neck extended (if no suspected cervical spine injury)
2
**Landmark Identification:** Palpate thyroid cartilage, then cricoid cartilage
identify the cricothyroid membrane
3
**Skin Incision:** Make a vertical midline skin incision (approximately 3-4 cm) overlying the cricothyroid membrane to improve visualization and access, or a horizontal stab incision directly over the membrane
4
**Membrane Puncture:** Puncture the cricothyroid membrane with a scalpel (e.g., #11 or #15 blade) in a horizontal direction
A slight rotation of the scalpel can widen the opening
5
**Bougie Insertion:** Introduce a flexible bougie (e.g., 60 cm, angled tip) through the incision into the trachea, aiming caudally
Ensure tactile feedback of tracheal rings or the characteristic "hold-up" of the bougie tip as it passes the carina
6
**Tube Advancement:** Advance a small endotracheal tube (typically 6.0 mm ID) over the bougie into the trachea until the cuff is just past the membrane
7
**Bougie Withdrawal:** Withdraw the bougie
8
**Tube Securing and Ventilation:** Inflate the tube cuff, secure the tube, and confirm placement with capnography and auscultation
Begin ventilation
9
**Definitive Airway:** This is a temporizing measure
conversion to a surgical tracheostomy or definitive endotracheal intubation should be performed when the patient is stable.
Equipment Required:
A pre-prepared airway kit is essential
This typically includes a scalpel (e.g., #11 or #15 blade), a flexible bougie (e.g., 60 cm), a small endotracheal tube (e.g., 6.0 mm ID with cuff), a syringe for cuff inflation, gloves, antiseptic solution, sterile gauze, and a source of oxygen and ventilation
Some kits may include a specialized cricothyrotomy device.
Complications
Early Complications:
Immediate complications can include significant hemorrhage from vascular injury (e.g., anterior jugular veins, thyroid vessels), creation of a false passage, esophageal perforation, tracheal injury (e.g., posterior wall perforation), subcutaneous or mediastinal emphysema, and failure to establish an airway
Damage to surrounding structures like the recurrent laryngeal nerve can lead to vocal cord paralysis
Injury to the cricoid cartilage in children can lead to subglottic stenosis
Infection is also a risk.
Late Complications:
Late complications may include subglottic stenosis, which can manifest as stridor and dyspnea
vocal cord paralysis
tracheal stenosis
persistent tracheocutaneous fistula
and cosmetic deformity at the neck incision site
Chronic hoarseness or voice changes can also occur.
Prevention Strategies:
Preventing complications relies on precise anatomical landmark identification, meticulous technique, and appropriate use of equipment
Adequate training and simulation are vital
In pediatric patients, needle cricothyrotomy is often preferred to avoid damage to the cricoid cartilage
Prompt conversion to a definitive airway once the patient is stabilized can minimize prolonged use of the emergency airway and associated risks.
Prognosis
Factors Affecting Prognosis:
The prognosis is primarily dependent on the speed of intervention and the underlying reason for the CICO situation
Rapid establishment of an airway in a CICO scenario significantly improves the likelihood of survival and reduces the severity of hypoxic brain injury
Comorbidities, the duration of hypoxia prior to intervention, and the occurrence of complications during the procedure also impact the outcome.
Outcomes:
When performed successfully and rapidly in a CICO situation, EFONA can be life-saving
Survival rates can be high if the procedure is timely
However, morbidity can be significant due to the severity of the initial condition and potential procedural complications
Neurological outcome is heavily influenced by the duration and severity of hypoxia
Long-term sequelae such as subglottic stenosis can affect quality of life.
Follow Up:
Patients who have undergone emergency front-of-neck access require close monitoring and follow-up
This includes assessment for airway patency, signs of infection, and evaluation for long-term complications such as stenosis
Depending on the urgency and invasiveness, conversion to a surgical tracheostomy may be planned once the patient is stable and the need for airway support is established
Specialist otolaryngology or thoracic surgery consultation is often required for long-term management and potential reconstructive procedures.
Key Points
Exam Focus:
Focus on the CICO algorithm: "Can't Intubate, Can't Oxygenate." Understand the indications for EFONA, especially the scalpel-bougie-tube technique
Be able to identify anatomical landmarks precisely
Recognize immediate and late complications
Differentiate between needle and surgical cricothyrotomy, and know when each is appropriate, particularly in pediatric patients
Understand the temporizing nature of EFONA and the need for definitive airway management.
Clinical Pearls:
Always have a pre-prepared airway kit readily accessible
Practice the procedure on manikins regularly to maintain proficiency
In a CICO scenario, do not hesitate
act decisively
Verbalize anatomical landmarks clearly during the procedure
Confirm tube placement with both capnography and auscultation
Remember that EFONA is a bridge to a definitive airway.
Common Mistakes:
Failure to identify landmarks correctly, leading to an incorrect incision site
Inadequate incision size or depth
Failure to secure the airway after incision due to anatomical distortion or bleeding
Advancing instruments blindly without confirmation of tracheal entry
Misinterpreting bougie feedback
Delaying the procedure due to indecision or lack of equipment
Not converting to a definitive airway when appropriate.