Management of the failed airway during anesthesia

INTRODUCTION — A failed airway occurs when the clinician is unable to oxygenate or ventilate the patient during attempts at airway management. Promptly recognizing a failed airway and rapidly restoring airway access in this critical scenario is imperative for reducing the risk of potentially serious airway-related morbidity and mortality. This topic reviews the approach to management of the failed airway and techniques for invasive airway access during anesthesia.

Other aspects of airway management for anesthesia are discussed separately.

●(See "Airway management for induction of general anesthesia".)

●(See "Management of the difficult airway for general anesthesia in adults".)

●(See "Complications of airway management in adults".)

Emergency cricothyrotomy in other care settings is typically approached differently and is discussed separately.

●(See "Emergency cricothyrotomy (cricothyroidotomy) in adults".)

●(See "Needle cricothyroidotomy with percutaneous transtracheal ventilation".).

DEFINITION OF THE FAILED AIRWAY — A failed airway in the operating room occurs when there is a failure to maintain adequate alveolar oxygenation in a patient by facemask, supraglottic airway (SGA), or endotracheal intubation despite optimal attempts at these techniques. This is also referred to as a "cannot intubate/cannot oxygenate" (CICO) or "cannot intubate/cannot ventilate" scenario.

Difficult airway guidelines recommend a maximum of three best attempts at oxygenation with each noninvasive airway management techniques [1-3]. The 2021 American Society of Anesthesiologists Difficult Airway guidelines recommend a maximum of three attempts, plus one by a more experienced clinician (algorithm 1 and figure 1) [4]. Repeated attempts without changing the technique are not likely to be effective [5]. Multiple attempts also increase the risk of airway trauma and obstruction, and may decrease the effectiveness of subsequent attempts and other techniques [6].

●Facemask oxygenation is considered unsuccessful after additional maneuvers have been attempted including a two-handed, two-person technique and insertion of oropharyngeal or nasopharyngeal airways.

●Oxygenation via SGA is considered unsuccessful after attempts with different types or sizes of devices.

●Endotracheal intubation is considered unsuccessful when a maximum of three optimized intubation attempts have failed in securing airway access, plus one more by a more experienced clinician. Each attempt should have a significant variation in the technique by using a different clinician, a different laryngoscope blade, video-assisted laryngoscopy, or flexible scope intubation through an SGA.

When best attempts at noninvasive SGA techniques have failed, a failed airway or CICO emergency must be declared and a prompt transition to an invasive technique must be initiated.

INCIDENCE AND CONSEQUENCES OF FAILED AIRWAY IN THE OPERATING ROOM — The reported incidence of a failed airway in the operating room as defined above ranges from 1 in 50,000 to 1 in 2803 general anesthetics [7-9]. Examples of relevant studies include the following:

●The Fourth National Audit Project (NAP4) in the United Kingdom found that serious airway events requiring emergency invasive airway access occurred in 1 in 50,000 general anesthetics. Seventy four percent of cases of cannot intubate/cannot oxygenate (CICO) occurred in patients who were undergoing head and neck surgery [7].

●In a retrospective multicenter study of approximately 98,000 general anesthetics performed from 2010 to 2012 in Japan, CICO occurred in three patients (1 in 32,000 cases) [8].

●In a registry-based study of 452,461 patients from the Danish Anaesthesia Database, emergency surgical airways were performed in approximately 1 in 17,000 cases of adults undergoing general anesthesia in the operating room [10].

●In a prospective single institution study of airway events during 2803 anesthetics over an eight-week period in the Netherlands, one case of CICO occurred; it was in a patient with head and neck cancer [9].

The failed airway is a rare adverse event but can result in life-threatening outcomes. CICO can result in hypoxia, brain damage, cardiac arrest, and death, and has been reported to cause up to 25 percent of anesthesia-related deaths [11]. In a review of malpractice claims related to difficult endotracheal intubation from the Anesthesia Closed Claims Project database from 2000 to 2012, CICO occurred in 80 percent of claims [6].

TRAINING AND PREPAREDNESS FOR MANAGEMENT OF THE FAILED AIRWAY — Good crisis management principles must be utilized to optimize the chances of success in managing a difficult or failed airway [12]. Clinicians involved in airway management should ideally participate in regular training exercises or simulations. Human factor failures contribute to unsuccessful emergency airway management [1,6]. These factors must be considered when developing airway management strategies at an individual, team, and institutional level [13].

Help should be requested at the earliest opportunity when a difficult airway is encountered to mobilize additional skilled personnel and equipment [4]. Guidelines for difficult airway management emphasize the importance of limiting repeated procedural attempts, promptly recognizing failure, and transitioning to the next step in airway management to minimize delays and avoid task fixation [1,3,14]. With respect to cannot intubate/cannot oxygenate (CICO), this means making an immediate decision to proceed to a surgical airway.

The failed airway is a high-acuity scenario in which clinicians and teams can become cognitively overloaded, leading to suboptimal management. Cognitive aids can be helpful in providing a shared mental model to facilitate decision making and communication, and avoid fixation errors [5]. One such aid is called the Vortex approach, a circular or cone shaped visual aid that divides airway management into a green zone of safety (ie, adequate oxygenation) at the outer edge, surrounding a vortex that culminates in emergency front of neck access [2]. For the Vortex approach, face mask ventilation, placement of an SGA, and intubation are called lifelines. If a best attempt using any one of the three lifelines is unsuccessful (≤3 attempts at each), management circles through the other two lifelines, and if unsuccessful, proceeds to the center of the vortex, which requires emergency surgical access.

Difficult airway management equipment should be standardized at an institutional level, and should be readily available in every anesthetizing location. Some authors have suggested that invasive airway equipment should be packaged as a kit that is easily identifiable and contains all of the necessary equipment [15]. Clinicians and teams involved in airway management should be familiar with the location and use of this equipment.

We agree with guidelines from the Difficult Airway Society in the UK, which state that anesthesiologists should be trained in both the technical procedure for performing scalpel cricothyrotomy and decision making aspects of the failed airway, with regular reinforcement and practice [1].

DECISION TO PERFORM EMERGENCY AIRWAY ACCESS — When airway difficulty is encountered, help should immediately be summoned, and the emergency pathway of a difficult airway algorithm should be followed (algorithm 1 and figure 1) [4]. If a failed airway occurs, emergency invasive airway access must be attempted immediately. (See 'Definition of the failed airway' above and 'Return to spontaneous ventilation' below.)

●In a number of cases of airway complications related to failed airways reported to the Fourth National Audit Project (NAP4), problems with fixation error (eg, repeated attempts at intubation) and related delay in performance of an emergency surgical airway were identified [16].

●In a review of closed malpractice claims related to difficult airway management, in 40 percent of cases that involved cannot intubate/cannot oxygenate (CICO), there was a delay in obtaining a surgical airway; approximately two-thirds were related to a delay in the anesthesiologist calling for a surgical airway [6].

Return to spontaneous ventilation — f Rescue of the failed airway should be directed towards emergency invasive airway access techniques, rather than attempts at awakening the patient. In a failed airway scenario, recovery of airway patency and spontaneous ventilation by awakening the patient after the induction of general anesthesia represents a potential rescue pathway [1,4,17,18]. However, there are practical limitations to safely achieving this in a timely manner that must be considered before choosing this route [19]. The primary limitation to awakening the patient with a failed airway is the time required to reverse neuromuscular block and/or the respiratory depression caused by induction agents.

●Reversal of neuromuscular block – Reversal of neuromuscular block after an intubating dose of a neuromuscular blocking agent cannot be relied upon to restore spontaneous ventilation in time to prevent hypoxic injury in a CICO scenario. In one trial, recovery from neuromuscular block was assessed in 115 surgical patients were randomly assigned to receive succinylcholine 1 mg/kg intravenous (IV) followed by spontaneous recovery, versus rocuronium 1.2 mg/kg IV, followed three minutes later by reversal with sugammadex 16 mg/kg IV [20]. Recovery of the first train-of-four twitch to 10 percent occurred at over four minutes for rocuronium/sugammadex, and at over seven minutes after succinylcholine. Full recovery of the first twitch to 90 percent occurred at over six minutes after rocuronium/sugammadex, and at 11 minutes for succinylcholine. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Reversal of neuromuscular block' and "Monitoring neuromuscular blockade", section on 'Train-of-four'.)

In addition, deep neuromuscular block is required for emergency airway access; reversing block can delay emergency access if spontaneous ventilation is not restored [1,3].

●Reversal of respiratory depression – The respiratory depression caused by other induction agents (eg, hypnotics, sedatives, opioids) can delay the return of spontaneous ventilation and patient responsiveness even after reversal of neuromuscular blockade [19].

CHOICE OF INVASIVE AIRWAY TECHNIQUE — Options for invasive airway access include surgical (scalpel) cricothyrotomy, percutaneous (needle) cricothyrotomy with a narrow-bore or wide-bore catheter, or surgical tracheostomy. The choice of technique depends on the expertise of the operator, availability of equipment, and technical patient factors. For invasive airway access performed by anesthesiologists when cannot intubate/cannot oxygenate (CICO) occurs in the operating room, we suggest using a scalpel cricothyrotomy for most patients. We use the scalpel-bougie-tube technique described below, an approach that is consistent with recommendations from the Difficult Airway Society in the United Kingdom [1]. Other authors feel that with appropriate training and immediate availability of the necessary equipment, anesthesiologists can safely perform percutaneous techniques as first line techniques for rescue from CICO [21,22].

When a surgeon who can perform a surgical tracheostomy and necessary equipment are readily available, a surgical tracheostomy can be performed as effectively and safely as a scalpel cricothyroidotomy [7,10]. Advantages and disadvantages of these techniques are discussed in the sections here.

Needle cricothyrotomy is preferred rather than scalpel cricothyrotomy in children younger than 10 to 12 years of age due to anatomic differences of the airway. (See "Emergency cricothyrotomy (cricothyroidotomy) in adults", section on 'Relative contraindications' and "Needle cricothyroidotomy with percutaneous transtracheal ventilation".)

Scalpel cricothyrotomy — There are several methods for performing a scalpel cricothyrotomy with insufficient evidence to support the superiority of a particular approach. A systematic review of the literature on techniques for emergency cricothyrotomy found four small studies that compared surgical techniques in human cadavers or anesthetized sheep [23]. Success rates were similar across techniques; the quality of data was judged to be low to very low.

The advantages of a scalpel cricothyrotomy include the following:

●It requires minimal equipment, and that equipment is already available in an operating room (ie, a number 10 scalpel blade, a tracheal tube introducer [bougie], and a 6 mm internal diameter cuffed tracheal tube)

●It allows use of standard low pressure ventilation with the anesthesia machine breathing circuit or bag valve mask

●Capnography can be used to confirm correct tube placement

●It protects against aspiration

●High first-attempt success rate ranging from 80 to 100 percent [7,24]

Percutaneous narrow bore catheter cricothyrotomy with transtracheal ventilation — This technique involves placing a narrow-bore catheter (<4 mm) through the cricothyroid membrane into the trachea, using an over-the-needle technique. A disadvantage is that this technique requires a high-pressure ventilation device and catheter connection equipment to allow transtracheal jet ventilation, equipment that is not readily available in many anesthetizing locations (see "Needle cricothyroidotomy with percutaneous transtracheal ventilation"). In addition, a narrow-bore cannula is not a secure airway and does not protect against aspiration.

This technique may be attractive to anesthesiologists given their familiarity with over-the-needle techniques. However, needle cricothyrotomy is associated with high incidences of complications and failure.

●In the Fourth National Audit Project (NAP4) in the United Kingdom, in 19 cases in which a narrow-bore cannula was used for the first attempt at an emergency surgical airway, 12 failed and were rescued with alternative techniques [7]. Common problems were catheter kinking, misplacement, and disconnection from the ventilation source.

●In a systematic review of the literature regarding complications of transtracheal jet ventilation in CICO emergencies, the incidence of complications was 51 percent, including device failure in 42 percent and barotrauma in 32 percent [25]. Several studies reported subcutaneous emphysema that hindered further attempts at airway management.

Percutaneous wide bore catheter cricothyrotomy — This technique involves placing a wide-bore catheter (≥4 mm) in the trachea, using a Seldinger technique (catheter over a guidewire) and dilator, or by using a rigid cannula-over-needle device. The wide-bore catheters used for this technique have standard endotracheal tube connectors and can be connected to the anesthesia breathing circuit or bag-valve-mask to allow low pressure ventilation and capnography. Some catheters have cuffs and protect from aspiration (picture 1). (See "Emergency cricothyrotomy (cricothyroidotomy) in adults", section on 'Seldinger technique'.)

Percutaneous wide-bore catheter cricothyrotomy may have a high failure rate, similar to narrow-bore catheter cricothyrotomy. NAP4 found a failure rate of 43 percent when this technique was used, with subsequent rescue with scalpel techniques [1,7].

Surgical tracheostomy — Surgical tracheostomy is typically performed between the first and second or second and third tracheal rings, lower in the trachea than cricothyrotomy (see "Tracheostomy in adults: Techniques and intraoperative complications", section on 'Anatomic location'). Thus, in cases where there is an obstruction or anatomic disruption in the infraglottic larynx (eg, tumor, laryngeal fracture, or laryngotracheal disruption), a tracheostomy is preferred over a cricothyrotomy. Tracheostomy is more familiar to surgeons and is a reasonable option when a surgeon with expertise and the necessary equipment are immediately available during a CICO event. However, tracheostomy is not an appropriate approach for anesthesiologists, who typically lack the necessary training [26,27].

Surgical tracheostomy may be a rescue technique when other approaches have failed [1].

●All rescue attempts using a surgical tracheostomy were successful in eight failed percutaneous cricothyrotomies in anesthesia-related cases from NAP4 [7].

●A systematic review of 342 emergency surgical tracheostomies reported a 100 percent success rate in accessing the airway [28]. The majority of these procedures were performed by trauma, general, and ENT surgeons in a trauma setting.

INVASIVE AIRWAY TECHNIQUES — Here we describe the scalpel-bougie-tube technique for surgical cricothyrotomy. Other techniques for surgical cricothyrotomy (ie, scalpel-finger-bougie, rapid and modified four-step techniques) and percutaneous narrow bore and wide bore catheter cricothyrotomy are described separately. (See "Needle cricothyroidotomy with percutaneous transtracheal ventilation" and "Emergency cricothyrotomy (cricothyroidotomy) in adults", section on 'Preferred technique: Scalpel-finger-bougie'.)

Preparation — Before performing an invasive airway procedure, administer 100% oxygen into the upper airway via nasal cannula, position the patient with the neck extended (for patients without cervical spine injury), and ensure full neuromuscular blockade.

Identify the cricothyroid membrane — The cricothyroid membrane (CTM) may be difficult to identify by palpation, particularly in patients with obesity, and in females compared with males [29]. We use the technique called the laryngeal handshake to identify the CTM, consistent with recommendations from the Difficult Airway Society (figure 2) [1].

The laryngeal handshake is described here. The anatomy of the neck surrounding the CTM and identification using simple palpation are discussed in detail separately (figure 3). (See "Emergency cricothyrotomy (cricothyroidotomy) in adults", section on 'Clinical anatomy'.)

Perform the laryngeal handshake as follows: (figure 2)

●With the nondominant hand, grasp the greater horns of the hyoid bone using the thumb and index finger.

●Move the hand from side-to-side to appreciate the three-dimensional anatomy of the laryngeal structures. The larynx is suspended from the hyoid and moves as a unit.

●Slide the fingers and thumb caudally to the thyroid laminae.

●Move the hand from side-to-side and adjust the grip if necessary to evenly grasp the larynx around the midline.

●Slide the hand caudally to grasp the cricoid cartilage with the middle finger and thumb, palpating the CTM with the index finger.

The limited literature comparing the laryngeal handshake with simple palpation suggests that the laryngeal handshake is at least as accurate for identification of the CTM [30,31], and may be more accurate for identifying the midline [30,32].

If the CTM is not easily identified or is misidentified during the procedure, the CTM should be identified by dissection as follows:

●Make an 8 to 10 cm sagittal incision in the midline of the neck, from caudal to cephalad.

●Use blunt dissection with fingers of both hands to separate tissues and identify the CTM.

●Proceed with scalpel cricothyrotomy as described below [1].

Scalpel-bougie-tube cricothyrotomy — (figure 4)

●Lubricate the distal tip of a size 6 mm internal diameter endotracheal tube.

●Stabilize the larynx using the thumb and middle finger of the nondominant hand.

●Using the dominant hand, make a stab incision through the CTM with a number 10 scalpel blade, with the blade oriented perpendicular to the axis of the trachea and the sharp edge of the blade towards the clinician.

●With the blade still in the incision, rotate the blade to turn the sharp edge caudally.

●Insert a bougie through the incision into the trachea by sliding the tip along the scalpel blade. Advance the bougie 10 to 15 cm. No resistance should be felt while advancing the introducer, though the clinician may feel "clicks," as the tip of the introducer passes over tracheal rings. Remove the scalpel.

●Insert the endotracheal tube (ETT) in a rotating motion over the bougie and into the airway. Stop advancing the tube once the cuff enters the trachea to minimize the risk of endobronchial intubation.

●Inflate the ETT cuff. Remove the bougie, and ventilate.

●Confirm correct ETT placement with capnography, auscultation of breath sounds, and chest rise.

●Secure the ETT.

MANAGEMENT AFTER AIRWAY RESCUE — After adequate oxygenation is achieved, the team must decide whether to proceed with surgery or awaken the patient.

●If the surgery is not urgent or an emergency, in most cases the safest option is to defer the procedure, and awaken the patient from anesthesia after reversal of neuromuscular block [1].

●For urgent or emergency surgery, a secure airway must be established before the procedure. If a cuffed tracheal tube was used for airway rescue, surgery can proceed with that tube in place. Otherwise, a surgeon should be consulted to establish a definitive airway.

Prolonged use of a cricothyrotomy may lead to higher incidence of subglottic stenosis, voice change, and dysphagia [33]. There is insufficient evidence to conclude that tracheal tubes placed for emergency cricothyrotomy can be safely used beyond the acute event [34,35]. Thus, some authors recommend conversion to tracheostomy if prolonged use of the airway is expected.

COMPLICATIONS OF CRICOTHYROTOMY — The reported rates of complications of emergency cricothyrotomy ranges from 0 to 50 percent, depending on the specific technique, the clinical setting, and clinician experience [28,35]. Most of the available data is from pre-hospital, emergency department, and intensive care unit settings. Venous bleeding occurs commonly, arising from venous plexuses that run across the cricothyroid membrane (CTM) [36,37]. Arterial bleeding occurs less often [38], and may be due to injury of the cricothyroid artery at the level of the superior CTM [39] or the superior thyroid artery as a result of misplacing the incision too laterally [36]. Other early complications include tracheal perforation, damage to the larynx, and creating a false tract. Ventilation into a false tract can result in subcutaneous emphysema, which can distort airway anatomy and make subsequent attempts at airway management more challenging.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Airway management in adults".)

SUMMARY AND RECOMMENDATIONS

●Definition – A failed airway (or "cannot intubate/cannot oxygenate" [CICO] scenario) occurs when oxygenation is not possible despite optimal attempts at facemask ventilation, ventilation with a supraglottic airway (SGA), and endotracheal intubation. Guidelines recommend a maximum of three attempts at each of these techniques plus one more by a more experienced clinician before declaring a failed airway and performing an emergency surgical airway (algorithm 1 and figure 1). (See 'Definition of the failed airway' above.)

●Training and preparedness – Clinicians involved in airway management should ideally participate in regular training exercises or simulations. Equipment for performing an emergency invasive airway should be standardized at an institutional level, and should be readily available in every anesthetizing location. (See 'Training and preparedness for management of the failed airway' above.)

●Decision to perform emergency invasive airway access – If a failed airway occurs, emergency invasive airway access must be attempted immediately. Delay in performing an invasive airway can result in hypoxic injury. Return to spontaneous ventilation is not feasible in most cases of failed airway in the operating room. (See 'Decision to perform emergency airway access' above.)

●Invasive airway techniques

•Choice of technique – For invasive airway access performed by anesthesiologists, we suggest using a scalpel cricothyrotomy for most patients (Grade 2C). Scalpel cricothyrotomy has a high success rate (80 to 100 percent), and requires only equipment that is readily available in the operating room. Because a standard endotracheal tube (ETT) is used, it allows ventilation with the anesthesia machine breathing circuit and use of capnography and protects against aspiration. (See 'Scalpel cricothyrotomy' above.)

Other invasive airway options include percutaneous needle cricothyrotomy with narrow or wide bore catheters, or surgical tracheostomy. (See 'Choice of invasive airway technique' above.)

•Scalpel cricothyrotomy technique – We use a scalpel-bougie-tube technique as follows, with further detail above (figure 4). (See 'Scalpel-bougie-tube cricothyrotomy' above.)

-Identify the cricothyroid membrane (CTM). We use the laryngeal handshake, which is shown in a figure (figure 2). (See 'Identify the cricothyroid membrane' above.)

-Make a stab incision in the CTM, perpendicular to the axis of the trachea.

-Rotate the scalpel blade 90 degrees.

-Insert a bougie through the incision into the trachea.

-Insert an ETT over the bougie, inflate the cuff, and remove the bougie.

●Management after airway rescue – Whether to proceed with surgery after airway rescue depends on the urgency of the planned procedure. (See 'Management after airway rescue' above.)

•For most elective surgery, the patient should be awakened and surgery deferred.

•For surgery that must proceed, a secure airway is required; if a cuffed tracheal tube was not placed for airway rescue, a surgeon should establish a definitive airway.