Guidelines for Evaluating the Airway Prior to Extubation in the ICU.
Background
The incidence of acute upper airway obstruction (UAO), and particularly stridor associated
with laryngeal/subglottic edema following extubation is in the range of 2-16%.1 Approximately
1% of all extubated patients will require re-intubation specifically for stridor.2 Stirdor usually
occurs within several minutes3 to 1 hour4 following extubation, but also has been reported to
occur up to 8 hours.2
There are several risk factors associated with the development of acute UAO following
extubation. Prominent risk factors include difficult/traumatic intubation,2 prolonged requirement
for mechanical ventilation,2 prior incidence of traumatic self-extubation (i.e.: decannualtion with
an inflated cuff),5 neurotrauma,6 female gender7 and obesity.8
Analysis of data from the SFGH quality-assurance weaning data base revealed that in 318
medical/surgical/trauma patients who required more than 48hrs of mechanical ventilation, and
who underwent an initial trial of extubation, 9 patients required re-intubation for some form of
upper airway obstruction within 96 hours (2.8%). Of these 9 cases, stridor was specifically cited
in 3 cases (0.9%). The majority of patients (67%) required re-intubation within 24 hrs (mean
time to re-intubation = 7.7 hrs). These patients were characterized as having a prolonged course
of mechanical ventilation (mean = 6 days), having neurological disease/trauma (67%), female
(56%) and older (mean age = 55 years).
To reduce the probability of acute upper airway obstruction following extubation at SFGH,
the following guidelines were created to standardize evaluation of the airway in order to improve
identification of patients at increased risk. In addition, we have made recommendations for the
approach to extubating patients at high-risk for acute upper airway obstruction, as well as
therapeutic interventions that should be implemented when airway obstruction occurs.
Identification of patients who are at high risk for developing acute upper airway obstruction
following extubation can be analyzed according to 3 categories that address anatomic
considerations, patient history and diagnostic tests. It is particularly important that the risk
assessment include standard anatomic features likely to make re-intubation difficult in the event
of acute UAO (Table 1). From this we have devised a tool to guide the clinician in utilizing the
anesthesia service for an airway consultation (Table 2).
Approved 3/1/2010; Revised 6/7/2012
Process for Airway Evaluation
1. Formal Airway History is gathered by members of the ICU team (physicians, nurses and
respiratory therapists) upon admission to the ICU/at the time of intubation. The
respiratory therapists will be primarily responsible for maintaining the airway history
data for determination of the Extubation Risk Assessment Score (Appendix).
2. The primary document of interest is the record of intubation (anesthesia record,
intubation record or emergency department record). In addition, as part of their report,
respiratory care practitioners assisting with intubation should also document this
information in their notes. The following information should be gathered:
a. The degree of difficulty (defined as greater than 3 attempts (by an experienced
anesthesiologist or emergency department physician (e.g.: failed attempts at
intubation by an intern or subintern does not constitute a difficult intubation).
b. The ease of manipulating the head into a sniff position
c. The ability to visualize the vocal cords during intubation.
d.
Evidence of airway trauma as a result of intubation attempts (suctioning of blood
from the hypopharynx or the trachea following intubation).
3. Mandated Cuff Leak Tests: Prior to initiating the SBT/DSI protocol, respiratory
therapists will perform a cuff leak test in patients determined to have High Risk for
developing acute UAO. These being:
a. Presence > 3 “Moderate” Risk Factors
b. Factors that carry a very significant for UAO (e.g. high cervical cord damage,
upper airway infection, trauma or surgery, inhalation injury, etc (see Airway Risk
Assessment Tool).
c. Cuff leak test can be performed in non-high risk patients at the discretion of The
ICU team.
4. Cuff Leak Test Methodology: In adult patients all cuff leak tests are performed using
the volume-based measurement described by Miller.5 Analysis of SFGH qualityassurance data using the volume cuff leak test in over 160 patients reveals a positive
predictive value of 55% and negative predictive value of 97% using the cutoff value of
110 mL. An appropriate volume-based measurement is not currently available for
pediatric patients. Therefore alternative pressure-based reclusion-based tests may be
used to evaluate airway patency in pediatric patients ventilated with small tidal volumes.
5. Anesthesia Consult required in high risk patients with a poor or absent cuff leak, in
whom extubation is contemplated. A formal airway evaluation may be performed by an
anesthesia resident or fellow in consultation with and anesthesia attending. Part of this
evaluation may include direct laryngoscopic visualization to examine the vocal cords and
upper airway. An anesthesia consult can be requested in any patient in whom the ICU
team has airway concerns.
6. Interservice Communication: Extubation should be deferred temporarily in patients
with direct visual evidence of airway edema. Decisions regarding subsequent airway
management should be reached by consensus between the anesthesia, primary and critical
care services. These decisions include whether to defer extubation pending re-evaluation
at a further time point, short course [24 hr] of steroid therapy, extubation in the OR, or
conversion to a tracheostomy).
Approved 3/1/2010; Revised 6/7/2012
7. Patients who undergo steroid therapy should be re-evaluated either by cuff leak test and
laryngoscopic exam after 24 hrs of steroid therapy and prior to an extubation trial.
8. Extubation of High Risk Patients: Extubation of high risk patients with an insufficient
cuff leak test should be undertaken only at a time when an attending anesthesiologist or
his/her designee is readily available to perform reintubation if necessary during the periextubation period (i.e.: 30 minutes). In addition, it should only occur at a time when a
respiratory therapist can be readily available to initiate emergency therapy. Extubation of
the patient with a diagnosis of “difficult airway” should only occur during the day. Easy
availability of emergency respiratory therapy interventions (such as the ability to deliver
aerosolized racemic epinephrine along with non-invasive ventilation or heliox) should be
in place prior to extubation.
Therapeutic Options:
Prophylaxis
In patients with direct visual evidence of airway edema, a short course [24 hr] of steroid therapy
may reduce airway inflammation sufficiently to allow successful extubation. A recent metaanalysis9of 7 prospective, double-blinded, randomized-controlled trials concluded that
corticosteroids administered prior to a planned extubation reduces the risk of post-extubation
stridor and subsequent need for re-intubation.
Steroids are more likely to be effective if administration begins at least 4 hours prior to
extubation, and are most appropriate when targeted to patients at high-risk for developing postextubation. In the experimental studies reviewed, a variety of dosages were studied. Typically
either 40 mg methylpredisolone or 5 mg dexamathasone is administered intravenously every six
hours for 24 hours prior to extubation. A cuff leak test and or direct laryngoscopy should be
repeated after steroid therapy and prior to the extubation trial.
Treatments
Patients who are at high-risk for developing acute UAO should have at least one the following
therapies readily available at/near the bedside prior to extubation. All patients who develop signs
of UAO should have therapy initiated rapidly. The following are guidelines for escalating
therapy in response to acute UAO post-extubation.
Stridor
1. All at-risk patients should receive prophylactic therapy using warm humidified oxygen
immediately following extubation. This is the most basic treatment for mild stridor and
should be instituted for at least 4-8 hrs following extubation.
2. For patients who develop post-extubation stridor, aerosolized racemic epinephrine
(Vaponefrin, Micronefrin) should be administered. Approximately 2-5 mg (1-2 mL
of a 2.25% solution) diluted in 3-5 mL of NS should be aerosolized preferably using a
small-volume mask nebulizer. An additional treatment can be given at approximately 15
min. Onset of action is approximately 5 min with a duration of approximately 1 ½ to 3
hrs. Repeated use of racemic epinephrine should be done with caution as tachyphylaxis
and paradoxical bronchospasm, therefore alternative adjunctive therapies should be
considered (see #3). Racemic epinephrine should be used with caution in patients with
hypertension or recent myocardial infarction.
Approved 3/1/2010; Revised 6/7/2012
3. Patients in whom stridor worsens or does not improve after 1-2 aerosolized racemic
epinephrine treatments should be re-intubated promptly.
4. If aerosolized racemic epinephrine appears to ameliorate stridor, consideration should be
given to incorporating other therapy options such as non-invasive ventilation or heliox
therapy. Heliox has been reported in the pediatric literature to reduce severe croup scores
as effectively as racemic epinephrine.10 Therefore heliox can be used as a temporizing
measure to limit dosing requirements with racemic epinephrine. Effective heliox therapy
requires an FiO2 of < 0.40 and therefore is not an option in patients with severe
hypoxemia.
5. At the discretion of the respiratory therapist/ ICU physician, aerosolized racemic
epinephrine can be delivered in conjunction with either non-invasive ventilation or heliox
depending upon the level of respiratory distress.
6. Close hemodynamic and Q-30 min to Q-1 hour arterial blood gas monitoring should be
implemented in those patients who appear to be responding to therapy.
Anatomic Obstruction ( poor upper airway muscle tone)
The choice of interventions or order of escalation is left to the discretion of the clinician basedupon the severity of symptoms (e.g.: snoring vs. sustained complete obstruction of the upper
airway)
1. Placement of nasal airway
2. Initiation of high-humidity, high-flow nasal oxygen therapy
3. Initiation of non-invasive ventilation either as nasal CPAP titrated between 5-15 cm H2O
or BiPAP (inspiratory presures of 10-20 cm H2O with expiratory pressures of 5-10 cm
H2O).
Post-Obstructive Pulmonary Edema
Following the relief of acute UAO, the development of post-obstructive pulmonary edema is a
distinct possibility. Clinicians should be prepared to institute aggressive supportive therapy. The
primary therapy for post-obstructive pulmonary edema is positive pressure ventilation (either
invasive or non-invasive) with moderate-to high levels of PEEP (10-15 cm H2O) high FiO2, and
lung-protective ventilation (VT 6-8 mL/kg). Ancillary therapies such as use of diuretics and/or
aerosolized beta-agonists may accelerate the re-absorption of pulmonary edema and hasten
recovery. Post-obstructive pulmonary edema, although sometimes dramatic, is a self-limiting
phenomenon that generally resolves within 24 hours.11
Initial Quality Assurance Monitoring Plan
A pilot monitoring project will be launched in both the MICU and SICU to evaluate all patients
who either are intubated for > 48 hrs, or have an obvious risk factor for developing acute UAO
(e.g.: morbid obesity, traumatic intubation, facial trauma, etc). The pilot project will assess the
feasibility of the process and to detect deficiencies in the monitoring or treatment regimen,
All completed ERAS worksheets will be collected and maintained by the critical care QA director
and maintained in a database.
Approved 3/1/2010; Revised 6/7/2012
References
1. Jaber S, Chanques G, Matecki S, et al. Post-extubation stridor in intensive care unit
patients. Risk factors, evaluation and importance of the cuff-leak test. Intensive Care
Med. 2003; 29:69-74.
2. Darmon JY, Rauss A, Dreyfuss D, et al. Evaluation of risk factors for laryngeal edema
after tracheal extubation in adults and its prevention by dexamethasone: A placebocontrolled, double-blind multi-centered study. Anesthesiology 1992; 77(2): 245-251.
3. Wang C-L, Tsai Y-H, Huang C-C, et al. The role of the cuff leak test in predicting the
effects of corticosteriod treatment on postextubation stridor. Chang Gung Med J. 2007;
30: 53-61.
4. Maury E, Guglielminotti J, Alzieu M, et al. How to identify patients with no risk for
postextubation stridor? J Crit Care 2004; 19(1): 23-28.
5. Miller RL, Cole RP. Association between reduced cuff leak volume and postextubation
stridor. Chest 1996; 110: 1035-1040
6. Sandhu RS, Pasquale MD, Miller K, et al. Measurement of endo tracheal tube cuff leak
to predict postextubation stridor and need for reintubation. J Am Coll Surg. 2000; 190:
682-687.
7. Jaber S, Jung B, Chanques G, et al. Effects of steroids on reintubation and postextubation stridor in adults: meta-analysis of randomized controlled trials. Crit Care
2009; 13:R49: 1-11.
8. Erginel S, Ucgun I, Yildrim H, et al. High body mass index and long duration of
intubation increase post-extubation stridor in patients with mechanical ventilation.
Tohoku J Exp Med. 2005; 207: 125-132.
9. Jabir S, Jung B, Chanques G, Bonnet F, Marret E. Effects of steroids on reintubation and
post-extubation stridor in adults: mata-analysis of randomized controlled trials. Crit Care
2009; 13: R49: 1-11.
10. Weber JE, Chudnofsky CR, Younger JG, et al. A randomized comparison of heliumoxygen mixture (heliox) and racemic epinephrine for the treatment of moderate to severe
croup. Pediatrics 2001; 107(6): 1-4.
11. Kallet RH, Daniel BM, Gropper M, et al. Acute pulmonary edema following upper
airway obstruction: case reports and brief review. Respir Care 1998; 43(6): 476-480.
Approved 3/1/2010; Revised 6/7/2012
Table 1. Anatomic Features Associated with Difficult Translaryngeal Cannulation
Short Neck
Small Chin
↑ Neck Circumference
Large Tongue
Facial Hair
↑ Body Mass Index
Facial/Neck Trauma
Protruding Maxillary Incisors
Table 2 Airway Risk-Assessment Tool (Modified Version)
Risk
Stratification
High Risk:
Moderate Risk:
Intervention
Leak Test Required
Leak Test: Clinician’s Discretion
Risk Factors
3 or More Moderate Risk Factors
Traumatic or Difficult Intubation

Documented trauma, or

4 attempts, or

Fiberoptic scope required
Inhalation Injury or Major Burns
(> 30% TBS)
Traumatic Extubation
Upper Airway, Infection, Mass,
Trauma or Surgery
Morbid Obesity BMI > 35)
Cervical Spine Fracture C1-C5
Neurologic Disease /Injury
Anterior Spinal Surgery
Mechanical Ventilation > 6 days
(i.e: unplanned ETT removal with inflated cuff)
(e.g.: prolonged prone position)
Facial Trauma or Surgery
Female
*Anesthesia consult is indicated whenever an extubation trial is contemplated in a patient with High-Risk
Factors AND
a poor leak test (< 110 mL). The initial evaluation may be performed by an anesthesia resident in
consultation with an anesthesia attending.
Approved 3/1/2010; Revised 6/7/2012