awake blind nasoendotracheal intubation: a comprehensive review

J Oral Maxillofac Surg

52:1303-1311,1994

Awake Blind A

Nasoendo tracheal In tuba tion: Comprehensive Review

JACKSON P. MORGAN III, DDS,* RICHARD H. HAUG, DDS,t AND W. C0RBEl-T HOLMGREEN, DDS, MD*

Awake blind nasoendotracheal intubation remains the first technique of choice in securing an emergent airway for various compromising circumstances before the performance of surgical access. Although the procedure may seem straightforward, numerous technical modifications can make this method more effective for the patient and easier for the clinician. A comprehensive discussion is presented in this article, including a historical perspective, indications, contraindications, anatomic considerations, technical modifications, and alternatives to awake blind nasoendotracheal intubation. It is designed as a thorough review for the surgeon in clinical practice who may at some time be called on to emergently secure a compromised airway.

History

The history of endotracheal intubation for airway management and control precedes the discovery of anesthesia. In 1543, Andreas Versalius, the renowned anatomist of Brussels, first described endotracheal intubation.’ In Human Corporis Fabrica Libri Septem, he reported the successful artificial ventilation of a pig through a tube inserted into its trachea.2 Two hundred forty-two years later, Kite designed an endotracheal tube for use in the resuscitation of drowning victims.’ In 1796, Herholdt and Rafin developed lifesaving pro- tocols for drowning victims that featured endotracheal intubation and mouth-to-mouth resuscitation.*

* Assistant Professor of Surgery, MetroHealth Medical Center and the Case Western Reserve University of Medicine, Cleveland, OH.

t Director, Division of Oral and Maxillofacial Surgery, Met- roHealth Medical Center; and Associate Professor of Surgery, Case Western Reserve University School of Medicine, Cleveland, OH.

$ Assistant Professor of Anesthesiology, The University of Texas Health Sciences, Center at San Antonio, TX.

Address correspondence and reprint requests to Dr Morgan: Met- roHealth Medical Center, Division of OMFS, 2500 MetroHealth Dr, Cleveland, OH 44109-1998.

0 1994 American Association of Oral and Maxillofacial Surgeons

0278-2391/94/5212-0013$3.00/O

McEwen in 1880 administered chloroform through an endotracheal tube, a technique that was slow to gain acceptance until World War II.3

Blind nasotracheal intubation was first described by Desault in 18 144 and later by Kuhn in 1902.5 Rowbo- tham in 19206 recognized that blindly passed nasal catheters frequently entered the trachea, but it was not until 1930 that Magill’s paper in the British Medical Journal led to an expanded use of the awake intubation technique.7 Intubation of a patient’s trachea with the individual in possession of his or her protective upper airway reflexes was, and continues to be, regarded as the safest airway management approach in many clinical situations.‘,8-‘5

Indications for Awake lntubation

In general, awake intubation is indicated when problems are anticipated in managing the patient’s airway during induction of anesthesia.‘4.‘6,‘7 For awake intubation to be successful, the patient should be able to follow simple commands such as “open your mouth” and “take a deep breath.” Additionally, adequate spontaneous ventilatory exchange and an intact cough reflex should normally be present. With these clinical parameters met, the following are situations in which awake intubation is recommended:

FULL STOMACH

An 8- to 12-hour delay in gastric emptying may occur secondary to trauma, severe gastric pain, duode- nal disorders, fear, and the onset of labor.15.‘8,‘9 It has been estimated that 18% of all anesthetic deaths are caused by regurgitation and aspiration of vomitus.*’ As an alternative to rapid sequence induction, patients with full stomachs may be managed safely with awake intubation.

LIMITED MOBILITY

Individuals with limited opening of the mouth secondary to trauma, developmental or anatomic anoma-

1303

1304 BLIND NASOENDOTRACHEAL INTUBATION

lies, musculoskeletal deformities, or destructive pro- cesses of the mandible or vertebrae are candidates for awake intubation.‘“.2’-26 When mobility of the cervico- thoracic region is restricted, the endoscopist cannot align the axis of the mouth and pharynx to properly visualize the glottis.

FACIALTRAUMA

For patients who have facial trauma and who are developing difficulty in maintaining a patent airway, awake intubation should be performed as early as possible to avoid the consequences of subsequent edema that may necessitate tracheostomy. Cervical spine injury must always be considered as a possibility in this group of individuals.

Orofacial infections such as Ludwig’s angina may pose significant hazards during conventional intubation and awake intubation may be indicated.‘,” Direct laryngoscopy in these patients may lead to rupture of pharyngeal abscesses, with subsequent aspiration of the contents into the lungs. The awake intubation technique is also recommended for management of emergency tonsillectomy and adenoidectomy when compli- cated by infection.28*29

CONTRAINDICATIONTO MUSCLE RELAXATION

Patients in whom airway assistance through an endotracheal tube is needed but muscle relaxants are contraindicated may be managed with awake intubation. These include individuals who are semiconscious or conscious after trauma, cardiovascular accidents, or poisoning.3 Using a muscle relaxant in these patients also may complicate or prevent successful intubation when undergoing general anesthesia. Relaxation of the pharyngeal and laryngeal muscles from the use of muscle relaxants may lead to collapse of the pharynx and supraglottic larynx.3G32 Supraglottic masses, if unde- tected, may lead to airway obstruction secondary to soft tissue collapse on paralysis of the patient.4*33 Din- nick3 reported that in most of his cases the patients were able to exchange air satisfactorily in the resting state; however, with the assumption of a supine position, along with the administration of muscle relaxants and other drugs that reduce muscle tone, an upper airway obstruction was precipitated.34

FAILED INTUBATION

Manipulation required for exposure of the larynx and placement of the endotracheal tube may produce

tissue edema, hematoma, bleeding, and increased secretions. The potential for complete airway obstruction becomes real if intubation is prolonged and repeated attempts at intubation are made.“‘.”

DIFFICULT AIRWAY

Misevaluation of the airway is one of the leading causes of anesthetic deaths described in the literature.‘.34.3” Obese, short-necked individuals with or without mandibular retrognathia are often difficult to intubate by direct laryngoscopy because of minimal visibility and accessibility of laryngeal structures despite profound muscular relaxation.9.36 Awake intubation is often needed to maintain a patent airway because these patients may become obstructed easily once anesthesia is induced.

PULMONARY COMPLICATIONS

Awake intubation may be useful in patients with inspiratory sttidor at rest.“““37 This may be of particu- lar significance in pediatric patients. In infants and children, the closing volume is higher than the func- tional residual capacity, permitting airway closure during quiet breathing. Collateral airway ventilation does not appear until 8 years of age, predisposing the infant and young child to a greater risk of distal alveolar collapse.37 Airway resistance is approximately four times greater in infants than in adolescents, with the small airways contributing the greatest degree of resistance in children younger than 5 years of age. Superim- posed inflammation of the airway, such as bronchio- litis, or a reactive process such as asthma, compromises the pediatric respiratory system to an even greater degree, with the higher airway resistance and closing volume.37.38 Hypoxia further depresses the level of con- sciousness, which in turn relaxes the pharyngeal structures with potential loss of the patient’s natural airway.

DEPRESSED PROTECTIVE REFLEXES

Individuals of extreme age and with a precarious cardiovascular status are particularly likely to regurgi- tate and aspirate during induction of general anesthesia, because their protective reflexes are often depressed.2~22~39 Pontoppidan and Beeche?9 claimed that the elderly have relatively obtunded laryngeal and pharyngeal reflexes. Awake intubation may be considered in some of these patients before induction of general anesthesia.

ADDITIONAL INDICATIONS

Other indications for awake intubation include un- stable cervical fractures in which flexion or extension

MORGAN, HAUG. AND HOLMGREEN 1305

of the neck is contraindicated, a patient with a history of previous difficulty with intubation, and when airway difficulties such as tracheal deviation, laryngeal polyps, or hemorrhagic epiglottitis are anticipated.‘,2,9.36.40 Fi- nally, awake intubation should be considered in patients with delicate fixed dental appliances or with se- verely protruding and unsupported anterior teeth. Difficult or improper laryngoscopy in these patients may result in damage to the dental prosthesis or avul- sion of a tooth, with the inherent danger of aspiration.‘,13

Contraindications to Awake lntubation

Contraindications to awake nasal intubation include cases of nasal obstruction secondary to congenital mal- formation, the presence of neoplasms or foreign bod- ies, acute sinusitis or mastoiditis. severe nasal bone fractures, serious bleeding disorders, or the risk of bac- terial endocarditis 2.‘.7~36*4’-61 . . Additionally, basilar skull, cribriform plate, or orbitoethmoidal complex fractures with resultant herniation of the brain or with cerebro- spinal rhinorrhea should be managed with alternative techniques of intubation.“-48

Anatomic Considerations

Anatomic considerations are especially important for successful anesthesia of the larynx. The larynx re- ceives its innervation through two branches of the va- gus nerve, the superior and inferior laryngeal nerves?9 The superior laryngeal nerve, after leaving the vagal trunk at the level of its inferior ganglion, passes toward the larynx, where it divides into a small external and a larger internal branch. The external branch moves forward on the thyrohyoid membrane in company with the superior laryngeal nerve, courses along the lateral aspect of the superior constrictor, and ends in the cricothyroid muscle. The internal branch curves forward on the thyrohyoid membrane accompanied by the superior laryngeal artery, penetrates this membrane, and breaks up into a number of branches that are distributed to a small portion of the posterior aspect of the root of the tongue and a large portion of the laryngeal mucosa.50.5’

The laryngeal muscles are voluntary and striated.52 The 15 intrinsic muscles lie entirely within the larynx, and the extrinsic muscles (six pairs) connect the larynx to the surrounding structures and elevate it toward the hyoid bone. The cricothyroid muscle, a vocal cord ten- sor, is innervated by the external branch of the superior laryngeal nerve. All other intrinsic muscles of the larynx are innervated by the recurrent laryngeal nerve.

Local Anesthetic Techniques

Various local anesthetic techniques have been developed to facilitate awake intubation. In addition to the

topical application of local anesthetics by swab, spray, nebulization, or gargling, the superior laryngeal nerve block and the transtracheal block may be used.

SUPERIOR LARYNGEAL NERVE BLOCK

The superior laryngeal nerve block combined with topical application of a local anesthetic to the nose and oral cavity was first described by Zuck for tracheobronchial toilet in the conscious patient.” The superior laryngeal nerve is blocked at the point where it penetrates the thyrohyoid membrane.‘“.5’.54 The needle is inserted caudal to the hyoid bone, and 2 to 3 mL 2% lidocaine is deposited just below the greater comu of the hyoid bone. The block also can be achieved by applying cotton swabs soaked in 4% lidocaine to the left and right piriform sinuses with a curved Jackson forceps.” Anesthesia of this nerve provides sensory blockade of the larynx superior to the vocal cords. Risk of laryngeal dysfunction is not present because only the cricothyroid and inferior pharyngeal constrictor muscles are supplied by the superior laryngeal nerve. More im- portantly, the recurrent laryngeal nerve is not in the immediate vicinity of the block, and thus the risk of vocal adduction with subsequent airway compromise does not exist. Because of the partial loss of sensation, however, the potential risk of aspiration remains.

Gotta and Sullivar? reported a 92% success rate in a series of 140 blocks of the superior laryngeal nerve, and described only two minor complications: formation of a small hematoma that resolved by applying pressure and penetration of an already inserted endotracheal tube, necessitating reintubation.

TRANSTRACHEAL BLOCK

An additional local anesthetic technique known as the transtracheal (or translaryngeal) block is often used as an adjunct along with the superior laryngeal nerve block to anesthetize the airway inferior to the vocal cords. The cricothyroid space is the most accessible portion of the respiratory tract inferior to the glottis and is defined as the concavity lying between the con- vex border of the inferior portion of the thyroid cartilage and the superior portion of the cricoid cartilage.57 Canuyt and Rozier, in 1920, described their experience with cocainization of the larynx by means of a needle introduced through the cricothyroid membrane for thyroid, laryngeal, or tracheal surgery.5R.“9 By 1940, the technique was widely used for instilling a local anesthetic before bronchoscopy.6”6” Despite the use of a syringe and needle, the technique is a form of topical anesthesia.“‘.““.” Analgesia produced by this technique not only contributes to the smoothness of intubation but also allows the patient to be maintained in a lighter


plane of general anesthesia without excessive use of muscle relaxants.68

Light sedation of the patient may facilitate administration of the transtracheal block. Palpation of the thyroid notch, laryngeal prominence, and cricoid cartilage is performed in the midline. The cricothyroid space is the first depression noted. The larynx and trachea lie’ in close proximity to the skin in this region. The skin is made taut over these structures. With the index finger pointing to the cricothyroid membrane, the syringe containing the local anesthetic solution is held in the other hand and driven like a dart through the skin and underlying membrane.6~60*62~” After verification of needle placement by aspiration of air in the syringe, the injection is performed rapidly and the needle is withdrawn as fast as possible.69 During the injection, the patient should be advised not to move, swallow, or talk.” Local anesthetic agents used with the technique have included tetracaine (20 to 40 mg),63.66,67*70 lidocaine (2 to 3 mL 2% to 4% solution),10*71 and cocaine 100 to 200 mg.60,67 Epinephrine may be used with tetracaine or lidocaine to prolong their action but should be avoided when using cocaine. Firm pressure is applied over the site of injection to prevent subcuta- neous emphysema formation and possible hematoma development.”

Transtracheal anesthesia has the advantage of re- laxing the vocal cords so that the endotracheal tube may be inserted without hazard of spasm.62,73 The inci- dence of reflex cardiac arrhythmias during intubation is also reduced.66*67

Although relatively easily performed, certain pre- cautions should be followed when administering transtracheal anesthesia. First, the angle of needle insertion should be perpendicular to the skin surface. Angulation superiorly may cause vocal cord injury. Second, insertion of the needle should be restricted to protect the posterior tracheal mucosa if the patient coughs. Third, the recurrent laryngeal nerve and its entrance into the larynx at the level of articulation of the inferior comu of the thyroid and the cricoid cartilage must be appreci- ated.

OTHER LCMZAL ANESTHETIC TECHNIQUES

Other local anesthetic techniques to facilitate awake nasal intubation have been described. Perhaps the sim- plest method of anesthetizing the mouth is for the patient to gargle with a solution of lidocaine.75 Addi- tionally, Cooper and Watson“j used bilateral glossopharyngeal nerve and superior laryngeal nerve blocks for both bronchoscopy and awake intubations. The glossopharyngeal nerve block was done by using an angled tonsillar needle to administer 3 mL 4% lido- Caine or 0.75% bupivacaine solution.76 Bilateral in-

traoral glossopharyngeal nerve blocks have the advantage of obliterating the gag reflex.”

Baddour et al” used a second division maxillary nerve block to reduce patient discomfort before the passage of nasal endotracheal tubes. Starzl and Cru- zat” used a nasal catheter through which a topical anesthetic was sprayed in the upper airway before blind nasal intubation. Tilting the patient’s head from side to side after spraying the topical anesthetic through the catheter was found to assist in the spread of the solution.56

COMPLICATIONS OF LOCAL ANESTHETICS

Potential complications with the transtracheal block include penetration of the trachea posteriorly with subsequent mediastinitis or mediastinal emphysema, sys- temic reaction to the local anesthetic from rapid drug absorption, damage to the vocal cords, and injection of solution beneath the laryngeal mucosa with consequent airway obstruction.62~68~72~79

Aspiration of blood after using transtracheal or superior laryngeal blocks has been reported by several au- thors.20.80.81 Gold and BuechelF2 after reviewing the transtracheal technique, reported that the superior surface of the cords are not thoroughly anesthetized. This statement has been used to support the thesis that the transtracheal injection is the method of choice in patients with a full stomach because protective sphincter reflexes remain undisturbed. Waits” tested this assumption in 100 patients using a transtracheal block with a local anesthetic mixed with methylene blue. Protective sphincteric abduction at the aryepiglottic fold or at the false or true cords was lost in 85% of these patients. These complications are rarely reported, however, as is evident from a review of 17,500 transtracheal blocks.61 .6X66.68.70,82 Nevertheless, in the patient with a full stomach, the use of transtracheal and superior laryngeal blocks, as well as the topical application of anesthetics to the larynx and vocal cords, is to be discouraged.

Contraindications to transtracheal anesthesia include the presence of a tumor or enlarged thyroid gland over- lying the thyroid or cricoid cartilages, infection or car- cinoma of the tracheobronchial tract, or a history of bleeding disorders or bleeding high in the trachea.68

Other Measures to Facilitate Awake lntubation

Various drugs, either alone or in combination, have been used during awake intubation to minimize discomfort, to minimize the chance of aspiration or damage to the airway, and for providing amnesia of the procedure.

MORGAN, HAUG, AND HOLMGREEN 1307

Cocaine in doses of 1 to 2 ml_ of a 4% to 5% solution has been used to ensure nasal airway patency and to minimize epistaxis.’ The maximum safe clinical dose of cocaine is 3 to 5 mg/kg.83 Other factors, such as the method and rate of administration, should be considered in dose selection. The analgesic effect of cocaine lasts approximately 90 minutes.% Of greater importance are that cocaine has a 5- to lo-minute latency period after administration and that the analgesic effect precedes the vasoconstrictive effect by an additional 5 minutesz4 Mille?4 recommends using small doses of 4% cocaine rather than a single, large, concentrated dose to reduce the chance of exceeding the maximum recommended dose.24

The toxicity of cocaine and its interactions with epinephrine are two major factors that must be considered when deciding to use cocaine. Reports have shown that cocaine placed topically in the piriform fossa is absorbed as if given intravenously.24 Cocaine blocks the uptake of catecholamine at adrenergic nerve end- ings and thus enhances the effects of both sympathetic nervous system stimulation and the administration of catecholamine.84 Therefore, extreme caution should be exercised when using cocaine in patients who have received epinephrine for fear of producing excessive cardiovascular stimulation.32

The effect of cocaine on the central nervous system is biphasic, with an initial sympathetic stimulation followed by general central nervous system (CNS) depression as inhibitory synapses are stimulated. Toxicity is manifested by excitement, anxiety, headaches, rest- lessness, tachycardia, and hypertension. Late effects include delirium, irregular respiration, mydriasis, con- vulsions and coma.85-87 In the event of cocaine toxicity, treatment consists of 100% oxygen by mask, intravenous propanalol titrated no faster than 1 mg intravenously (IV) per minute up to 5 mg, and diazepam 0.1 to 0.2 mg/kg IV.**

Reflex bradycardia resulting from intubation may be prevented by the IV administration of atropine or glycopyrrolate before intubation.89 Glycopyrrolate pro- duces less stimulatory effects on the CNS and heart rate than does atropine; the latter effect is of more importance in elderly individuals with decreased cardiac reserve.2.24 However, both drugs share the disad- vantage of decreasing the resting tone of the lower esophageal sphincter and therefore increasing the possibility of regurgitation.‘O

Cimetidine, a histamine Hz-receptor antagonist, has been shown to decrease gastric fluid volume and increase gastric fluid pH when 300 mg is administered IV 1 hour before intubation.7’ Ranitidine (100 mg IV), another HZ-receptor antagonist, has also been found effective when given 1 to 2 hours before induction.” If there is sufficient time, the routine inclusion of Hz-

receptor antagonists before intubation has been encour- aged, especially in emergency patients.24.92 The use of H2 antihistamines is preferred over antacids because they do not increase the gastric fluid vo1ume.9’ Also, particulate antacids may have adverse effects on the tracheobronchial tree if aspirated.93’94 When use of an antacid is desired, 30 mL 0.3 mol/L sodium citrate or two tablets Alka Seltzer (Miles, Inc, Elkhart, IN) in 30 mL water is recommended.28,95,9”

Metoclopramide acts both centrally and peripherally to stimulate gastric emptying and increase lower esophageal sphincter pressure, thus acting as an anti- emetic. This agent also should be considered when there is a concern with potential aspiration.97.98

The use of doxapram or 5% carbon dioxide as ventilatory stimulants has been advocated.24,36 The primary reasons for using these agents are to maintain deep spontaneous ventilation and to enhance abduction of the vocal cords to facilitate the passage of the endotracheal tube through the airway.

Finally, benzodiazepines such as diazepam (2 to 20 mg) or midazolam (2.5 to 10 mg) may be given intravenously before awake intubation to produce anterograde amnesia, thereby blocking the memory of any discomfort from the experience.72.88.99-‘“’

Nasotracheal lntubation

During nasotracheal intubation, the tube may theo- retically pass through six different routes as it is advanced. Submucosal dissection into the mucous membrane of the nose may occur. This can be recognized by increased resistance to the advancement of the tube, the inability to see the tube passing through the posterior oropharynx, and the loss of breath sounds coming through the nasotracheal tube. Bleeding from the mouth is another possible indication of submucosal dissection. Treatment in these cases may involve as little as spraying the nares with 1% phenylephrine or it may require a posterior nasopharyngeal pack.’ A change to the opposite naris is also advisable for reintubation. In addition, the patient must be protected from aspiration of blood by placing the table in the Trende- lenburg position and by suctioning blood from the oropharynx.’

Direction of the endotracheal tube into the epiglottic vallecula or the anterior commissure of the glottic opening also may occur. Clinical examination of the neck shows a bulge in the midline just superior to the thyroid cartilage. To correct this problem, additional llexion of the neck is performed, which directs the tube posteriorly.

Passage of the tube into the esophagus is manifested by the unimpeded advancement of the tube to its full length with an accompanied loss of breath sounds pre-


FIGURE 1. A, “Endotrol” endotracheal tube in passive position. B, Endotracheal tube tip angulation is determined by pulling on the ring

connected to the tip by an internally enclosed plastic line.

viously heard through the tube. In an awake person, phonation will be possible. Redirecting the tube more anteriorly while increasing neck extension corrects the situation.24 Use of an Endotrol (Mallinckrodt, Inc., Glens Falls, NY) endotracheal tube can facilitate this maneuver (Fig lA, 1B).

Lateral displacement into the piriform recess and sinus is manifested by loss of breath sounds and resistance to further tube advancement, with an accompa- nying bulge in the neck lateral to the laryngeal prominence.“’ Withdrawing the tube 2 to 3 cm while rotating it 45” to 90” helps to orient the tube to the midline. Manipulation of the thyroid cartilage externally also may be attempted to align the glottic opening with the tUbe.24

Obstruction to further advancement of the tube may occur at the entrance to the larynx, an occasional result of using a nasotracheal tube with an excessive curva- ture. Advancement of the tube beyond the level of the vocal cords may be impossible in this case because the tip is caught against the anterior wall of the larynx. Flexion of the head may resolve this problem by redirecting the tube further posteriorly and past the obstruction at the anterior laryngeal wall.

Finally, successful passage into the trachea may occur. Maximal abduction of the vocal cords occurs during the latter phase of inspiration, and at this phase of the respiratory cycle the tube is quickly passed through the glottis into the trachea, thereby minimizing vocal cord trauma.24 The technique of passing the tube at the moment of an explosive cough is also helpful, because the laryngeal aperture is again at its greatest diameter during this time.24 Successful intubation may be verified by one or more of the following: continued passage of air through the endotracheal tube as evidenced by excursions of the anesthesia bag; direct laryngoscopy; fiberoptic laryngoscopy; and by capnography showing an end tidal carbon dioxide tension of approximately 5% (esophageal reading should be 0%).

Awake intubation should be accomplished without the application of excessive force. Occasionally, a nasal endotracheal tube fails to make the bend as contact is made with the posterior wall of the nasopharynx. On laryngoscopy, the tube is not seen in the oropharynx. In this event, inspection for submucosal dissection into the nose or posterior nasopharynx should be done. If negative, a useful maneuver may be to insert a stylet, which has had a 90” bend placed in its distal 1.5 cm, into the nasotracheal tube.2 The tube then is reinserted until the bend in the tube passes the posterior nasopharynx, at which time the stylet is withdrawn and the tube is advanced.’ Additionally, awake intubation is best achieved when the patient is breathing spontaneously. Breath sounds heard through the end of the nasotracheal tube indicate the proximity of the tip of the tube to the laryngeal opening. The anesthetist should have his or her ear in close proximity to the tube connector to detect changes in breath sounds.24 An endotracheal tube whistle enhances auditory discrimination of breath sounds (Fig 2).

Although the aforementioned techniques have fo- cused on blind awake intubation, two other techniques are available that permit direct and indirect visualization of endotracheal tube placement. The fiberoptic laryngoscope or bronchoscope allows direct visualization of airway anatomy.‘03 It has become an important tool for the anesthetist when blind intubation fails, or when a difficult intubation is anticipated. Although use of the fiberoptic bronchoscope is simple conceptually, there is a significant learning curve that must be over- come before becoming proficient.‘2,‘04 In addition, blood and secretions can obliterate the field of vision. The reader is referred elsewhere for a detailed descrip- tion of fiberoptic-assisted intubation.‘0”,‘04

A method that allows indirect visualization of the airway is the “light wand” intubation technique. This approach was first described by Ducrow and later mod- ified by Raybum. ‘05~‘06 Raybum generally performed

MORGAN. HAUG, AND HOLMGREEN 1309

FIGURE 2. An endotracheal tube whistle facilitates hearing breath sounds.

this technique with sedation and regional anesthesia.‘” A flexible surgical light is lightly lubricated and inserted into an endotracheal tube until the light is just short of the distal tip. The operating room lights are dimmed and the light wand is turned on. The light wand and endotracheal tube are then inserted orally. This apparatus oftentimes first enters the esophagus, but as it is withdrawn it “pops” anteriorly. At this point a red glow is seen under the cutaneous surface in the anterior neck at a level just above the vocal cords. The endotracheal tube is then advanced into the trachea.

Once intubation is achieved and verified through the auscultation for equal breath sounds bilaterally in all lung fields, the endotracheal tube is well secured to prevent its displacement. Induction of general anesthesia through IV or inhalational routes is then performed as expeditiously as possible.

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