AIRWAY MANAGEMENT
| SUPRAGLOTTIC AIRWAY DEVICES —Terrence L. Trentman, MD, Assistant Professor of Anesthesiology, Mayo Clinic
College Of Medicine, and Staff Anesthesiologist, Mayo Clinic, Scottsdale, AZ
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| Portex laryngeal mask airway (Portex Soft Seal): translucent; single use; no aperture bars; cuff less permeable to
nitrous oxide; sized for adults (3, 4, and 5) like LMA (pediatric sizes also available); blue line in midline for straight
alignment; “just-seal” pressure (≈60 cm H2 O); gauze bite block may be used; intubate through bougie or over fiberoptic
bronchoscope (FOB), if necessary
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| Ambu laryngeal mask (AuraOnce and Aura40): AuraOnce single use and Aura40 autoclavable (≤40 times); no
aperture bars; available in 8 sizes (neonate through adult); integrated inflation line (part of airway tube); unique
features—reinforced tip does not fold over; anatomic curve (preformed); proximal area reinforced as bite block; Hagberg
study—observational; looked at Ambu in nonparalyzed anesthetized patients; found all adequately ventilated; concluded
it produces “safe and efficient seal; easy to insert”; insertion—similar to LMA; hold airway like flute; head
extension beneficial; push mask against hard palate and curve it around into airway; inflate cuff with just-seal pressure
(≈60 cm H2 O)
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| Intubating laryngeal airway (ILA): can be used as routine airway; also allows for intubation using standard oral endotracheal
tube (ETT; ≤8.5 mm); reusable form only (autoclave ≤40 times); adult sizes only; intubate over FOB or through
bougie; once ETT inserted, stylet placed on end of ETT to stabilize removal of ILA; unique features—oval-shaped breathing
tube; keyhole-shaped airway outlet; auxiliary airway hole; ridges in mask bowl; insertion tips—elevate tongue and
provide jaw lift (get tip underneath epiglottis to avoid obstructing airway outlet)
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| Chou adjustable airway device (ChouAirway): modified oral airway; rigid outer tube (like oral airway); flexible
inner tube; insert then attempt mask ventilation; for obstruction, slowly advance flexible inner tube in 1-cm increments
until patent airway established; adult sizes only
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| Cobra perilaryngeal airway (CobraPLA and CobraPLUS): uses high-volume low-pressure cuff to seal hypopharynx
(eg, adult size 4, 65 to 70 mL of air); CobraPLA has preformed anatomic curve; CobraPLUS has temperature
probe and distal CO2 monitor; positive-pressure ventilation (PPV) possible at ≤20 cm H2 O; can intubate via aperture
bars; large-diameter breathing tube fairly short, so easy to remove over ETT; 8 sizes (neonate to adult); cuff in upper hypopharynx;
Cook and Lowe—randomized crossover comparison of LMA vs CobraPLA; study stopped after 2 of 29 patients
in Cobra group aspirated; perhaps large proximal cuff blocked egress of regurgitant fluid; manufacturer aware of
>1000 cases without problems; insertion—insert with head extension until firm pressure felt (tip at upper esophageal
sphincter); pull back slightly, then inflate cuff
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| King laryngeal tube (King LT, LT-D, and LTS-D): known as laryngeal tube airway in Europe; available in reusable
or disposable (LT-D) form; both oropharyngeal and esophageal low-pressure high-volume cuffs; air pressure ≤80
mL; ventilation pressure ≤30 cm H2 O; appropriate for PPV; 3 sizes based on height of patient (4-5 ft, size 3; 5-6 ft, size
4; >6 ft, size 5); “looks a lot like a shortened single-lumen Combitube”; 2 ventilation outlets anteriorly; not marketed for
insertion of ETT; Hagberg study—prospectively evaluated insertion and function of King LT during spontaneous ventilation
in 50 patients; 86% first-attempt success; insertion time <5 sec in 90% of patients; easy to use and dependable;
ventilation outlets—original device had only anterior ventilation outlets; these can become obstructed and prevent ventilation;
in newer versions, lateral outlets added; King LTS-D—has second lumen for suction catheter; insert ≤18 F suction
catheter; PPV ≥30 cm H2 O; insert by entering from side, then rotate toward middle; inflation pressure ≈60 cm H2 O
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| Streamlined liner of pharynx airway (SLIPA Airway): shaped like boot; hollow chamber may decrease aspiration
risk; composed of heel, toe, and bridge; toe sits in entrance to esophagus, bridge at pyriform fossa, and heel snaps into
nasopharyngeal opening to hold device in place; adult sizes only; match size to dimension across thyroid cartilage (cornu to
cornu); insert with head extension and jaw lift; used during spontaneous ventilation or PPV; dislodge heel for removal by
pulling caudal and anterior; use ≤3 hr; remove while patient asleep; Miller study—used airway model; looked at ProSeal,
SLIPA, and LMA; both ProSeal and SLIPA provided protection against simulated regurgitation; also looked at SLIPA vs
LMA in 120 patients; both functioned adequately and equally easy to insert
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| Intersurgical supraglottic airway (i-gel): currently available only in United Kingdom (UK); single-use, disposable
airway; noninflatable cuff matches perilaryngeal anatomy; includes bite block and gastric channel
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| Comparative studies: criteria—ease of insertion; first-attempt success rate; quality of seal; position as judged by
FOB; hemodynamic response to insertion; airway trauma (as evidenced by blood on device or sore throat after removal);
spontaneous ventilation vs PPV; controversies—use of aperture bars; ideal insertion technique; indications for use (eg,
laparoscopic surgery, cesarean delivery); and single-use vs reusable devices (studies indicate residual proteins do survive
sterilization process)
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| OBSTRUCTIVE SLEEP APNEA —Bhargavi Gali, MD, Assistant Professor of Anesthesiology, Mayo Clinic College of
Medicine, and Staff Anesthesiologist, Mayo Clinic, Rochester, MN
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| Incidence: in 1990s, ≈4% of men and 2% of women estimated to have obstructive sleep apnea (OSA); ≤80% undiagnosed;
≤24% of men and 9% of women diagnosed with sleep disordered breathing
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| Pathophysiology: obstruction thought due to narrowing of airway caused by muscle relaxation during induction of
sleep; central sleep apnea due to lack of central drive
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| Definitions: apnea—cessation of breathing for ≥10 sec; hypopnea—reduction in airflow ≥10 sec (usually reduction
≥30%, and desaturation ≥3%); apnea-hypopnea index—number of apneic and hypopneic episodes during hours of
sleep (by itself, index ≥10 considered significant)
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| Classification of OSA: includes patient with apnea-hypopnea index of 5, who also has daytime sleepiness and somnolence
thought related to OSA; apnea-hypopnea index of 5 to 15 considered mild, 15 to 30 considered moderate, and >30
considered severe
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| Diagnosis and treatment: polysomnography gold standard for OSA; requires overnight stay in sleep laboratory; patient
usually monitored by video; also includes electroencephalography (EEG), electrooculography (EOG), electromyography
(EMG; focuses on limb and pharyngeal activity), pulse oximetry, blood pressure measurement, and
electrocardiography (ECG); monitor for episodes of OSA, desaturation (pulse oximetry drop ≥4%), and arousals; calculate
frequency based on events per hour to determine apnea-hypopnea index; continuous positive airway pressure
(CPAP) mainstay of treatment
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| Perioperative issues: difficult to get polysomnography on every patient (limited availability); important to identify patients
at higher risk; data suggest sleep reduced and highly fragmented on first postoperative day; no rapid eye movement
(REM) sleep during first postoperative night; REM rebound on second and third days postoperatively; increased intensity
and duration of REM rebound may be associated with increased hypoxemia (compared to preoperative sleep); effect of
medications—many agents used during perioperative period can worsen symptoms; may contribute to decreased pharyngeal
tone, increased airway resistance, and some attenuation of ventilatory and arousal responses to hypoxemia and
hypercarbia; may have worsening of underlying OSA; issues associated with OSA—perioperative hemodynamic instability;
myocardial ischemia; increased risk for stroke; electrolyte abnormalities; gut immobility and distention; study
data—patients having total hip or knee arthroplasty; those with OSA had increased perioperative morbidity and mortality;
complication rate 39% with OSA, 18% without OSA but with similar body mass index (BMI); OSA patients not using
CPAP had increased rate of serious complications, admission to intensive care unit (ICU), and hospital length of stay;
many patients on CPAP at home not given CPAP on first postoperative night
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| Recommendations: American Society of Anesthesiologists’ (ASA) guidelines; preoperative—institution or hospital
should develop protocol to screen for OSA; close review of medical records (especially with BMI >35, large neck, or
airway anatomic abnormalities); talk with family and patient together; if available, obtain sleep study results before surgery;
difficult to delay surgery, but if serious concern about OSA, consider initiating CPAP before surgery; if time
available, consider helping patient lose weight; assume patient having (or who has had) corrective surgery still at risk;
physical examination not shown to be highly effective in identifying patient with sleep disordered breathing;
screening—speaker’s institution uses simple screening questionnaire based on Flemons criteria; sensitivity, specificity,
and positive predictive value similar to other screening methods; questions relate to high blood pressure, snoring,
gasping, choking, or snorting, and neck measurement; score ≤15 considered low risk for OSA; >15, high risk for OSA;
intraoperative—ASA recommends consideration of local or regional anesthesia, if possible; also recommends continuous
monitoring of all patients having moderate sedation; use CPAP if evidence of obstruction occurs during sedation;
ensure all patients fully reversed at end of general anesthesia; extubate in fully awake state; ensure anesthesia provider
knows whether patient considered high-risk or low-risk before seeing or evaluating patient; postoperative—for pain
management, ASA recommends regional techniques, if feasible; avoid continuous opioid infusions (may decrease ability
to respond to hypoxia or hypercarbia); nonsupine positioning, if possible, depending on type of surgery; if significant
concern, patient should go to telemetry area or ICU; continuous oximetry without observer not same level of safety
as having patient on floor with pulse oximetry; postanesthesia care unit (PACU)—patients most likely to receive
high doses of narcotics; favorable nurse-patient ratio; staff interested and skilled in respiratory issues; staff asked to
look for and document hypoventilation, apnea, desaturations, and pain-sedation mismatch (visual analog score >5 and
high sedation score on Ramsey scale); patients initially evaluated 30 min after extubation or on arrival in PACU, whichever
occurs later; evaluated again at 60 min and 90 min; level 1 —patients with none of criteria documented throughout
PACU stay; level 2—includes patients who have criteria documented, but who “didn’t have it at the end” (also
includes patients on CPAP at home); level 3—includes patients who have criteria at >1 evaluation point, higher dose of
neuraxial opioid, or who required airway intervention in PACU (eg, application of CPAP)
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 | Outpatient surgery: lack of data prevents ASA from making “good recommendations” for outpatients; if local or regional
anesthesia used for outpatient procedure, same level of care anywhere; if general anesthesia planned and other risk factors
present, “other factors need to be considered” (eg, previous diagnosis of OSA, high risk, coexisting morbidities,
older age, need for postoperative opioids upon leaving hospital, nature of surgery and anesthesia, positioning at home,
adequacy of postdischarge observation, eg, vigilant family members, and facility capabilities)
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| AIRWAY MANAGEMENT IN THE ACUTE TRAUMA SETTING —D. John Doyle, MD, PhD, Professor of Anesthesiology,
Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, and Staff Anesthesiologist, Department
of General Anesthesiology, Cleveland Clinic, Cleveland, OH
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| Suggested contents of difficult airway portable storage unit: exhaled CO2 detector (eg, capnograph); esophageal
detector device (self-inflating bulb placed at end of ETT; reexpands quickly if in trachea, slowly in esophagus)
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| ASA airway examination: in trauma patient with unstable cervical spine, may be difficult to evaluate range of motion;
alternative techniques may be necessary; otherwise, 11-step airway examination process helpful
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| ASA difficult-airway algorithm in trauma setting: emphasizes importance of assessing likelihood of problems
with intubation, ventilation, and cooperation; other issues, including oxygenation and awake intubation vs induction of
general anesthesia “more or less the same”; if failure occurs with awake intubation, classic option of cancelling case not
possible in trauma patient; may be forced into invasive airway approach (eg, cricothyroidotomy); if attempting intubation
after induction of general anesthesia, option of awakening patient may not be available in emergency case
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| Closed head injury: important to know Glasgow Coma Scale (GCS; eye opening, verbal response, and motor response);
general principles—if difficult airway, perform awake fiberoptic intubation (provided patient cooperative, stable, maintains
spontaneous ventilation, and has GCS score >9); key issues—severity of injury and degree of cooperation; for GCS
score <9, rapid sequence induction (RSI; may require modification, eg, cricoid pressure; PPV, depending on clinical particulars);
if GCS score >9, and if patient cooperative, awake option preferred; key management points—avoid hypoxemia;
keep cerebral perfusion pressure >70 mm Hg; may need to temporarily hyperventilate if intracranial pressure increased
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| Cervical spine injury: general considerations—if difficult airway, perform awake intubation (provided patient cooperative,
stable, and maintains spontaneous breathing), especially if patient has neurologic symptoms from spinal cord injury (eg,
inability to move arms and legs); key issues—if neurologic deficit present, awake technique preferred; if airway examination
predicts difficult airway (eg, Mallampati class IV, small mouth), awake intubation also preferred; key management
points—maintain in-line immobilization (not traction); for RSI, maintain cricoid pressure with one hand supporting neck
from behind
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| Airway disruption: can occur at level of larynx and upper trachea (15% of cases), carina (80% of cases), and more distally
(≈5% of cases); laryngeal injury—may occur in sports activities (eg, hockey puck to larynx) or motor vehicle accidents
(eg, traumatic contact with steering wheel); airway may be at risk due to bleeding into airway and resulting
hematoma formation or edema; neck may be edematous, distorted, or exhibit crepitus with palpation; subcutaneous air
may be palpable in neck; voice may become hoarse; in severe cases stridor may be present; radiographic examination
may demonstrate air in neck soft tissue; deformity of air column in lateral neck x-ray may be present; key issues—for
major laryngeal or tracheal tear, perform awake technique; if lesions small or supralaryngeal, modified RSI may be appropriate;
key management points—maintain spontaneous ventilation, even with modified RSI technique; avoid PPV
proximal to tear; place ETT below tear (likelihood of forcing air into subcutaneous and mediastinal tissues reduced);
avoid transtracheal jet ventilation and LMA; maintain spontaneous breathing when possible; consider double-lumen tube,
depending on level of lesion (eg, carina or distal); consider cardiopulmonary bypass
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Suggested Reading
Cook TM et al: An evaluation of the Cobra Perilaryngeal Airway: study halted after two cases of pulmonary aspiration.
Anaesthesia 60:791, 2005; Dorges V: Airway management in emergency situations. Best Pract Res Clin Anaesthesiol
19:699, 2005; Flemons WW et al: Home diagnosis of sleep apnea: a systematic review of the literature. An evidence review
cosponsored by the American Academy of Sleep Medicine, the American College of Chest Physicians, and the American
Thoracic Society. Chest 124:1543, 2003; Gaitini L et al: A comparison between the PLA Cobra and the Laryngeal Mask
Airway Unique during spontaneous ventilation: a randomized prospective study. Anesth Analg 102:631, 2006; Gross JB et
al: Practice guidelines for the perioperative management of patients with obstructive sleep apnea: a report by the American
Society of Anesthesiologists Task Force on Perioperative Management of patients with obstructive sleep apnea. Anesthesiology
104:1081, 2006; Gupta RM et al: Postoperative complications in patients with obstructive sleep apnea syndrome undergoing
hip or knee replacement: a case-control study. Mayo Clin Proc 76:897, 2001; Hagberg C et al: An evaluation of
the insertion and function of a new supraglottic airway device, the King LT, during spontaneous ventilation. Anesth Analg
102:621, 2006; Hagberg CA et al: A multicenter study of the Ambu laryngeal mask in nonparalyzed, anesthetized patients.
Anesth Analg 101:1862, 2005; Han TH et al: The laryngeal mask airway is effective (and probably safe) in selected
healthy parturients for elective Cesarean section: a prospective study of 1067 cases. Can J Anaesth 48:1117, 2001; Harrison
MM et al: Incidence of undiagnosed sleep apnea in patients scheduled for elective total joint arthroplasty. J Arthroplasty
18:1044, 2003; Levitan RM et al: Initial anatomic investigations of the I-gel airway: a novel supraglottic airway
without inflatable cuff. Anaesthesia 60:1022, 2005; Miller DM et al: A streamlined pharynx airway liner: a pilot study in
22 patients in controlled and spontaneous ventilation. Anesth Analg 94:759, 2002; Miller DM et al: Advantages of ProSeal
and SLIPA airways over tracheal tubes for gynecological laparoscopies. Can J Anaesth 53:188, 2006; Miller DM et
al: Laboratory and clinical comparisons of the Streamlined Liner of the Pharynx Airway (SLIPA) with the laryngeal mask airway.
Anaesthesia 58:136, 2003; Rodricks MB et al: Emergent airway management. Indications and methods in the face
of confounding conditions. Crit Care Clin 16:389, 2000; van Zundert A et al: Comparison of three disposable extraglottic
airway devices in spontaneously breathing adults: the LMA-Unique, the Soft Seal laryngeal mask, and the Cobra perilaryngeal
airway. Anesthesiology 104:1165, 2006; van Zundert A et al: The anatomical position of three extraglottic airway
devices in patients with clear airways. Anaesthesia 61:891, 2006; Van Zundert AA et al: Comparison of the LMA-classic
with the new disposable soft seal laryngeal mask in spontaneously breathing adult patients. Anesthesiology 99:1066, 2003.
Educational Objectives
| The goal of this program is to familiarize anesthesia providers with new airway devices and ensure appropriate airway management
in patients with obstructive sleep apnea and in acute trauma situations. After hearing and assimilating this program,
the participant will be better able to:
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| 1. Identify the basic structure and function of new supraglottic airways.
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| 2. Properly insert the new supraglottic airways.
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| 3. Determine if the new supraglottic airways will function as conduits for intubation.
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| 4. Review the preoperative, intraoperative, and postoperative management of patients with obstructive sleep apnea.
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| 5. Describe airway management in the acute trauma setting, focusing on closed head injury, cervical spine injury, and
airway disruption.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty members to disclose relevant
financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts
were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial
interest. For this program, the faculty reported nothing to disclose.
Acknowledgements
Drs. Trentman and Gali spoke at the Mayo Clinic Symposium on Anesthesia and Perioperative Medicine, held February
21-24, 2007, in Scottsdale, AZ, and sponsored by Mayo Clinic College of Medicine; Dr. Doyle, at Survey of Current Issues
in Surgical Anesthesia, held November 11-15, 2006, in Naples, FL, and sponsored by the Cleveland Clinic, Division
of Anesthesiology, Critical Care Medicine, and Comprehensive Pain Management. The Audio-Digest Foundation thanks
the speakers and the sponsors for their cooperation in the production of this program.
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