Residency · Residency · Anesthesiology

Emergency Surgical Airway and Cannot-Intubate-Cannot-Oxygenate (CICO)

Definition and Significance of CICO

What is CICO?

Cannot Intubate, Cannot Oxygenate (CICO) describes the failure to secure the airway by conventional means (intubation) combined with the failure to maintain oxygenation by non-invasive means (mask ventilation, SGA). It represents the most critical airway emergency, carrying imminent risk of hypoxic brain injury and death. The incidence is approximately 1 in 50,000 general anesthetics — rare but catastrophic. NAP4 (the UK National Audit Project 4) identified CICO as a major contributor to airway-related deaths and brain injuries.

Why CICO Occurs

CICO arises from unanticipated difficult airways after induction of general anesthesia, progressive airway edema from repeated intubation attempts, laryngospasm unresponsive to treatment, airway pathology (tumor, infection, trauma) rendering all non-surgical techniques impossible, and failure to execute the difficult airway algorithm efficiently due to human factors and fixation errors.

NAP4 Key Findings

Overview

The Fourth National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society (2011) reviewed all major airway complications across the UK over one year. Of 184 major airway events reported, 46% occurred at induction, 33% during maintenance or emergence, and 21% in the ICU or ED.

Critical Lessons

Failure to plan for difficulty was the most common contributing factor. Obesity was the single most common patient risk factor. Aspiration was the leading cause of airway-related death. When emergency surgical airway was needed, delay in the decision to perform it was the primary problem — not technical failure. SGAs were often used inappropriately as definitive airways in high-risk patients, and poor capnography use contributed to unrecognized esophageal intubation.

Recommendations from NAP4

Capnography should be used for every intubated or sedated patient throughout anesthesia. A surgical airway plan should exist for every general anesthetic. All anesthesiologists should receive regular training in emergency cricothyrotomy. Airway assessment and planning must be improved. Second-generation SGAs should be preferred for rescue.

Emergency Cricothyrotomy

Anatomy of the Cricothyroid Membrane

The cricothyroid membrane lies between the inferior border of the thyroid cartilage and the superior border of the cricoid cartilage. Its average dimensions are 9-10 mm in height and 22-30 mm in width. In the midline, it is covered only by skin, subcutaneous tissue, and the membrane itself — no major vessels cross. It is located approximately 2-3 cm below the laryngeal prominence. Identification is performed by palpating the thyroid notch and sliding the finger inferiorly to the first depression below the thyroid cartilage prominence. Palpation is difficult in obese patients, short thick necks, female patients, those with edema, and those with previous neck surgery.

Techniques for Emergency Cricothyrotomy

Scalpel-Bougie-Tube Technique (Recommended)

This is the recommended first-line approach endorsed by DAS and most current guidelines. The steps are: stabilize the larynx with the non-dominant hand (laryngeal handshake), make a transverse stab incision through both skin and cricothyroid membrane simultaneously with a scalpel (#10 or #20 blade), rotate the scalpel blade 90 degrees (cutting edge caudally) to keep the incision open, insert a bougie through the incision alongside the scalpel blade into the trachea, railroad a 6.0 mm cuffed ETT over the bougie into the trachea, inflate the cuff, attach the circuit, and confirm with capnography. This technique uses familiar equipment, has a high success rate in simulation and clinical use, and can be completed in under 60 seconds with training. The key principle is a single stab through both skin and membrane simultaneously — no layered dissection.

Surgical Cricothyrotomy (Scalpel-Finger-Tube)

This alternative uses a vertical skin incision (some prefer it for identifying anatomy in obese patients), followed by blunt dissection to the cricothyroid membrane, a transverse incision through the membrane, finger insertion to confirm tracheal entry and maintain the opening, and insertion of a 6.0 cuffed tube. It is more time-consuming.

Needle Cricothyrotomy with Jet Ventilation

This approach is less recommended in adults due to higher complication rates. A large-bore (14G) IV cannula is inserted through the cricothyroid membrane and connected to a high-pressure oxygen source for jet ventilation. It provides oxygenation but not effective ventilation (CO2 removal is limited). Risks include barotrauma (especially with complete upper airway obstruction where gas cannot escape), subcutaneous emphysema, pneumothorax, pneumomediastinum, cannula kinking, displacement, and posterior tracheal wall perforation. Its primary indication is in pediatric patients under 8-10 years, where surgical cricothyrotomy carries higher risk of subglottic stenosis. Duration is limited and a definitive airway must be established urgently.

Commercial Cricothyrotomy Kits

Devices from Melker, Portex, QuickTrach, and others are available, using either Seldinger-based or direct insertion techniques. Familiarity with the locally available kit is essential. Evidence does not show superiority over the scalpel-bougie-tube technique, and these kits may increase time to completion in trained hands.

Identifying the Cricothyroid Membrane

Palpation Technique (Laryngeal Handshake)

The operator palpates the thyroid cartilage with the dominant hand and slides inferiorly to locate the cricothyroid membrane depression. This is difficult in 30-50% of females and obese patients.

Ultrasound-Assisted Identification

Pre-procedure ultrasound with a linear probe placed transversely over the anterior neck can identify the thyroid and cricoid cartilage, with the cricothyroid membrane appearing as a hypoechoic gap between them. This is increasingly recommended for pre-assessment in patients with difficult neck anatomy but is not practical during acute CICO due to time constraints.

Decision-Making in CICO

When to Declare CICO

CICO should be declared after failed intubation attempts (maximum 3+1 per DAS guidelines), failed SGA rescue (maximum 3 attempts, at least 1 with a second-generation device), and declining SpO2 despite all non-surgical oxygenation efforts. The most common error is hesitation and continued attempts at conventional airway management while hypoxia worsens.

Cognitive Factors Contributing to Delay

Fixation error leads to continuing intubation or mask ventilation attempts despite repeated failure. Anchoring bias produces the thought "this can't be happening; one more attempt will work." Authority gradient makes junior staff reluctant to declare CICO or suggest a surgical airway. Task fixation causes focus on one technique at the expense of the algorithm. Lack of practice with surgical airway leads to avoidance.

Team Communication

The CICO declaration should be verbal and clear: "This is a CICO situation. I need to perform an emergency cricothyrotomy." A cognitive aid (checklist or poster) should guide the algorithm. Roles should be assigned: one person performs the cricothyrotomy, one administers drugs, and one monitors. Closed-loop communication confirms actions and responses.

Post-Cricothyrotomy Management

Immediate

Tracheal placement must be confirmed with end-tidal CO2. The tube should be secured and the neck stabilized. Ventilation with 100% oxygen is initiated, and an arterial blood gas obtained. Sedation and paralysis should be considered to prevent movement and dislodgement.

Definitive Airway

Conversion to formal tracheostomy should be planned within 24-72 hours, since cricothyrotomy tubes should not remain long-term due to the risk of subglottic stenosis. ENT or surgical consultation for tracheostomy is needed. Oral or nasal intubation through the swollen airway should not be attempted immediately after CICO.

Documentation and Follow-Up

Detailed documentation of the event, techniques used, and timing is essential. The patient and family should be notified. Formal airway assessment and follow-up should be arranged. An incident report for quality improvement should be filed. An airway alert should be placed in the medical record (and a MedicAlert bracelet considered). A team debrief with psychological support for team members should be conducted.

Simulation and Training

Evidence for Simulation

Emergency cricothyrotomy is rarely performed (perhaps once in a career for most anesthesiologists), and skills degrade without practice. Regular simulation maintains competency, and high-fidelity simulation improves performance in CICO scenarios. Practice on cadavers, animal models, or high-fidelity simulators at least annually is recommended.

Training Focus Areas

Training should focus on cricothyroid membrane identification (palpation and ultrasound), the scalpel-bougie-tube technique under time pressure, decision-making and declaration of CICO (overcoming hesitation), team communication and use of cognitive aids, and integration into broader difficult airway algorithm practice.

<image>A detailed anatomical illustration of the anterior neck showing the thyroid cartilage, cricothyroid membrane, cricoid cartilage, and tracheal rings in sagittal and anterior views. The cricothyroid membrane is highlighted in red with dimensions labeled (9-10 mm height, 22-30 mm width). The relationship to the thyroid gland, cricothyroid artery (usually superior, running transversely), and overlying structures (skin, subcutaneous tissue) is shown. A cross-sectional view through the CTM shows the target plane for the scalpel incision.</image>

<image>A step-by-step illustrated guide for the scalpel-bougie-tube emergency cricothyrotomy technique: (1) laryngeal handshake identifying the CTM, (2) transverse stab incision through skin and CTM with a #10 blade, (3) scalpel rotated 90 degrees to maintain the opening, (4) bougie insertion through the incision directed caudally into the trachea, (5) railroading a 6.0 cuffed ETT over the bougie, (6) cuff inflation and circuit connection with capnography confirmation. Time stamps at each step showing the procedure should be completed in under 60 seconds. Warning inset showing common errors: incision too high, incision too deep (posterior wall injury), failure to stabilize the larynx.</image>

<image>A cognitive aid poster for the CICO emergency showing the DAS difficult airway algorithm with the final CICO pathway emphasized: declaration of CICO, call for help, position patient (extend neck if possible), perform scalpel-bougie-tube cricothyrotomy. A timeline from recognition to action shows the critical window before irreversible hypoxic injury (approximately 3-5 minutes of complete apnea in pre-oxygenated adult). Sidebar lists the essential equipment that should be immediately available: #10 scalpel, bougie, 6.0 cuffed ETT, syringe, capnography.</image>

Clinical Pearls

The single greatest error in CICO management is delay: the decision to perform a surgical airway is almost always made too late, not too early. The scalpel-bougie-tube technique is recommended because it uses equipment familiar to every anesthesiologist and has the highest success rate. A transverse stab incision through both skin and membrane simultaneously is faster and more reliable than layered dissection — anatomy should not be overthought during a CICO crisis. Pre-procedure ultrasound marking of the cricothyroid membrane should be considered for any patient with difficult neck anatomy before induction. Needle cricothyrotomy with jet ventilation has a high complication rate in adults (barotrauma, insufficient ventilation) and should not be the primary plan for adult CICO. Regular simulation training is essential because this procedure is too rare to maintain competency through clinical experience alone. After every difficult airway event, a thorough debrief should be conducted, airway findings documented, and the patient given a documented airway alert for future encounters.

References

• Cook TM, et al. Major complications of airway management in the UK: results of NAP4. Br J Anaesth. 2011;106(5):617-631.
• Frerk C, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth. 2015;115(6):827-848.
• Heard A, et al. Cricothyrotomy in the emergency surgical airway. Anaesth Intensive Care. 2021;49(3):186-198.
• Duggan LV, et al. The front of neck access: a systematic review. Can J Anaesth. 2021;68(2):200-217.
• Kristensen MS. Ultrasonography in the management of the airway. Acta Anaesthesiol Scand. 2011;55(10):1155-1173.

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