Overview
Definition:
Failed intubation refers to the inability to secure an airway via endotracheal intubation after multiple attempts
Laryngeal Mask Airway (LMA) rescue in this context involves utilizing an LMA as a supraglottic airway device as a temporizing or definitive measure when endotracheal intubation is not achievable, particularly in emergency surgical settings
It can serve as a bridge to definitive surgical airway or provide ventilation if endotracheal intubation is persistently unsuccessful.
Epidemiology:
The incidence of failed intubation is estimated to be between 1 in 200 to 1 in 2000 anesthetics, with higher rates in emergency situations
Factors contributing to failed intubation include anatomical abnormalities, obesity, cervical spine pathology, airway trauma, and limited surgical experience
The "cannot intubate, cannot ventilate" (CICV) scenario is a critical emergency with high morbidity and mortality.
Clinical Significance:
Failed intubation is a life-threatening emergency requiring rapid, decisive action
The surgical perspective is crucial as it often involves the consideration and performance of surgical airways (e.g., cricothyrotomy, tracheostomy) when less invasive methods fail
Effective LMA rescue can prevent progression to a CICV situation, buying vital time for definitive airway management and improving patient outcomes
Understanding LMA placement as a rescue tool is essential for surgical residents managing airway emergencies.
Indications For Lma Rescue
Primary Indication:
Inability to visualize the vocal cords or pass an endotracheal tube despite optimal attempts using standard and alternative techniques (e.g., videolaryngoscopy, bougie).
Secondary Indications:
As a temporizing measure in a suspected difficult airway scenario where intubation is likely to be challenging
To facilitate oxygenation and ventilation while preparing for or awaiting surgical airway placement.
Contraindications Relative:
Intact gag reflex (may cause gagging, vomiting, or aspiration)
known esophageal pathology
complete airway obstruction distal to the larynx
recent pharyngeal or laryngeal surgery or trauma
severe gastroesophageal reflux disease
morbid obesity (can make placement difficult).
Contraindications Absolute:
None, in the context of a true cannot intubate, cannot ventilate scenario, where the risks of not securing an airway far outweigh the risks of LMA insertion.
Surgical Approach To Failed Intubation
Algorithm Based Management:
Adherence to established difficult airway algorithms (e.g., DAS guidelines) is paramount
these algorithms often recommend trying an LMA after failed intubation attempts before proceeding to surgical airway.
Recognizing Failure:
Failure to pass the ETT after 3 attempts, or failure to achieve adequate oxygenation (SpO2 < 90%) or ventilation within 30-60 seconds despite attempts.
Transition To Surgical Airway:
If LMA insertion fails or is inadequate, immediate consideration of emergency front-of-neck access (eFNA), typically cricothyrotomy, is required
This is a surgical procedure and a critical step in managing the CICV situation.
Role Of Cricothyrotomy:
Cricothyrotomy is the preferred initial surgical airway in adults for the CICV scenario due to its speed and relative ease of performance compared to tracheostomy
It provides a direct pathway to the trachea below the level of potential upper airway obstruction.
Role Of Tracheostomy:
Tracheostomy is generally reserved for anticipated prolonged ventilation or as a definitive airway in elective settings
In the acute emergency of failed intubation and failed LMA, cricothyrotomy is the go-to surgical rescue.
Laryngeal Mask Airway Insertion Technique Rescue
Preparation:
Ensure appropriate size LMA is available
Lubricate the posterior aspect of the LMA cuff and the anterior slot
Deflate the cuff fully
Position the patient with the head in a neutral or slightly extended position (sniffing position if possible, but not at the expense of spinal stability).
Insertion Steps:
Hold the LMA like a pen, with the tube passing through the fingers
Advance the LMA against the palate with the index finger, pushing it towards the pharynx
Once resistance is met, continue advancing while rotating the LMA 180 degrees towards the patient's feet until a slight springy resistance is felt, indicating the LMA is seated in the pyriform fossa.
Cuff Inflation:
Inflate the cuff with the recommended volume of air
A properly inflated cuff creates a seal around the laryngeal inlet
Avoid overinflation, which can cause tissue damage or block the epiglottic opening.
Confirmation Of Placement:
Connect the breathing circuit and ventilate
Auscultate for bilateral breath sounds and absence of gastric sounds
Observe for chest rise
Use capnography to confirm end-tidal CO2 detection, which is the gold standard for confirming endotracheal or supraglottic airway placement.
Troubleshooting:
If LMA cannot be inserted, re-lubricate, reposition the head, or try a different size
If placement is confirmed but ventilation is poor, check cuff inflation, LMA position, and potential airway obstruction distal to the LMA
Consider removing and re-inserting.
Surgical Airway Placement Technique
Indication For Surgical Airway:
Failure to achieve adequate ventilation/oxygenation with LMA rescue, or if LMA is contraindicated or impossible to insert in a CICV scenario.
Technique Of Cricothyrotomy:
Identify the cricothyroid membrane between the thyroid and cricoid cartilages
Stabilize the larynx with the non-dominant hand
Make a horizontal or vertical incision through the skin and subcutaneous tissue over the membrane
Puncture the membrane with a scalpel or a dedicated cricothyrotomy device
Insert a small endotracheal tube (e.g., 6.0) or the LMA introducer/cannula through the opening
Secure the tube and connect to the ventilation circuit
Confirm placement with capnography and auscultation.
Technique Of Needle Cricothyrotomy:
A less invasive option, primarily for pediatric patients or as a temporary measure
Insert a large bore IV catheter (e.g., 14-16G) through the cricothyroid membrane
Connect to a high-pressure oxygen source via a modified Y-connector for jet ventilation
Note limitations in ventilation efficiency and risk of barotrauma.
Postoperative Care Surgical Airway:
Continuous monitoring of ventilation and oxygenation
Regular suctioning of secretions
Chest X-ray to confirm position and rule out pneumothorax
Transition to tracheostomy if prolonged airway support is anticipated.
Complications Of Surgical Airway:
Bleeding, infection, subcutaneous emphysema, pneumothorax, injury to surrounding structures (esophagus, recurrent laryngeal nerve), tracheal stenosis, vocal cord paralysis.
Complications Of Lma Rescue
Early Complications:
Sore throat, dysphagia, laryngospasm, bronchospasm, aspiration of gastric contents, pharyngeal or esophageal trauma, nerve injury (lingual, recurrent laryngeal).
Late Complications:
Hoarseness, persistent dysphagia, vocal cord dysfunction, tracheal stenosis (rare from LMA itself, more common with prolonged intubation or aggressive cricothyrotomy).
Prevention Strategies:
Careful patient selection, correct LMA size and technique, adequate lubrication, proper cuff inflation, prompt removal after procedure, prompt transition to definitive airway if LMA is insufficient, adherence to difficult airway algorithms.
Key Points
Exam Focus:
Understanding the sequence of airway management in failed intubation scenarios is critical for DNB/NEET SS
Recall the "cannot intubate, cannot ventilate" (CICV) emergency and the roles of LMA versus surgical airways.
Clinical Pearls:
Always have a difficult airway cart readily accessible
Practice LMA insertion on manikins
Recognize that LMA is a rescue device, not a primary intubation tool
Prioritize oxygenation and ventilation above all else
Be prepared to perform cricothyrotomy
it is a life-saving skill for surgeons.
Common Mistakes:
Delaying recognition of failed intubation
Excessive attempts at intubation without reassessment
Inadequate preparation for difficult airway management
Failure to recognize the need for surgical airway promptly
Inexperience with LMA insertion or cricothyrotomy technique
Over-reliance on LMA without backup plan for surgical airway.