Chapter 16. Digital (Tactile) Orotracheal Intubation

For patients who require orotracheal intubation, digital (tactile) intubation is an alternative technique to traditional direct laryngoscopy.1–12 This procedure involves using the index and middle fingers as a guide to blindly place the endotracheal tube into the patient's larynx. Digital tracheal intubation has been demonstrated to be a safe, simple, and rapid method.1 It should be considered as a secondary method of intubation when other methods prove difficult or impossible.1 It is particularly suited for prehospital and aeromedical use, where equipment and alternate intubation techniques are limited or unavailable. One study demonstrated an 88% success rate among paramedics who intubated with this technique.2

For this procedure, the only two significant anatomic structures that the intubator will encounter are the patient's tongue and the epiglottis. The epiglottis is the cartilaginous structure that is located at the root of the tongue and serves as a valve over the superior aperture of the larynx during the act of swallowing.3

Digital orotracheal intubation is an ideal alternative technique for intubating the comatose or chemically paralyzed patient when other more conventional methods for intubation have failed. In particular, this procedure is useful when oral secretions or blood inhibit the direct visualization of the upper airway.1 Since this technique involves minimal movement of the head and neck, it may be a suitable method for intubating patients with known or suspected cervical spine injuries. Digital intubation may be a useful procedure for paramedics and aeromedical personnel in the out-of-hospital setting, when trapped patients require intubation but are not in a position for more conventional methods.2 It is an alternative technique for out-of-hospital intubation where other techniques and equipment are unavailable or limited.

This procedure has also been performed successfully in intubating neonates.4,11,12 One study comparing neonatal digital intubation with direct laryngoscopy demonstrated digital intubation to be more rapid and more successful on the first attempt.5

There are no absolute contraindications to digital intubation. The main danger of this procedure is to the healthcare worker performing the intubation, who is at risk for having his or her fingers bitten by the patient. This technique should not be performed on any patient who is awake or semiconscious. It should be performed only on patients who are paralyzed or unconscious. Relative contraindications would be performing this procedure on a patient with multiple fractured teeth that may abrade or cut the intubator's fingers, or a patient whose ingestion may present a biochemical hazard to the intubator.

• Endotracheal tubes, various sizes
• Wire stylet, malleable (optional)
• 10 mL syringe
• Water-soluble lubricant or anesthetic jelly
• Bag-valve device
• Oxygen source and tubing
• Gauze, 4 × 4 squares

Endotracheal intubation in the Emergency Department is commonly performed on an emergent or urgent basis. If there is time, explain the risks, benefits, and complications of the procedure to the patient and/or the patient's representative.

The use of gloves, a bite block, and gauze over the teeth as guards are recommended when performing this procedure. The patient should be lying supine. If the patient has sustained a concerning mechanism of injury, the cervical spine should be immobilized. An assistant can help hold the patient's head to maintain in-line immobilization. Place the patient on continuous cardiac monitoring, pulse oximetry, and supplemental oxygen.

Prepare the endotracheal tube. Attach a 10 mL syringe to the cuff's inflation port. Inflate the cuff and inspect it for any air leaks. Deflate the cuff and leave the syringe attached to the inflation port. The use of a stylet is optional, but commonly used by most practitioners in this procedure.6 It may be used if the patient's larynx is anterior, the intubator has short fingers, or it is the physician's preference. Lubricate and insert the stylet until it is 1 cm proximal to the distal end of the endotracheal tube. Bend the malleable stylet just as it enters the endotracheal tube. This will prevent it from migrating distally and injuring the patient. Gently bend the distal end of the endotracheal tube into a “J.”1 Liberally lubricate the distal end of the endotracheal tube. Induce anesthesia (Chapters 8 and 10) if the patient is conscious.

The intubator should stand at the patient's right side and be facing the patient. Insert the index and middle fingers of the right hand into the right angle of the patient's mouth (Figure 16-1).1,5 Slide the fingers along the surface of the tongue until the epiglottis is palpated. The metacarpophalangeal joints of the index and middle fingers will usually be at the level of the patient's incisors in an adult. The tip of the epiglottis is approximately 8 to 10 cm from the incisors. Elevate the epiglottis with the index finger (Figure 16-2). The thumb of the left hand may be used to provide cricoid pressure if needed.7

With the left hand, insert the endotracheal tube along the left side of the patient's mouth and between the two fingers (Figures 16-1 & 16-2).1,5 Alternatively, the endotracheal tube can be advanced between the two fingers and the tongue. Gently advance the tip of the endotracheal tube into the patient's trachea (Figure 16-2). Do not advance the endotracheal tube if any resistance is encountered. Partially withdraw the endotracheal tube and reattempt to insert it into the patient's trachea. Alternatively, withdraw the endotracheal tube completely, bend it more sharply, and then attempt to insert it into the trachea. Have an assistant withdraw the stylet if one was used. Advance the endotracheal tube approximately 3 to 4 cm.1,8 While securely holding the endotracheal tube with the left hand, gently withdraw the right hand from the patient's mouth. Inflate the cuff of the endotracheal tube. Begin ventilating the patient while securely holding the endotracheal tube and confirming proper placement.

The technique of digital orotracheal intubation is not as simple as some may think. A patient's mouth may appear too small to allow an endotracheal tube and two fingers of the intubator. Use the fingers in the patient's mouth to push their jaw and tongue forward. If the patient's mouth still appears small, apply gauze squares over their mandibular incisors and push their mouth open further with the bases of the fingers in their mouth.

It may be difficult to blindly identify the patient's epiglottis. Insert your fingers in the midline of the patient's mouth and slowly push them posteriorly. The fingers will roll off the posterior portion of the tongue and allow you to palpate the epiglottis. Be careful to not push the epiglottis posteriorly. Once identified, move your fingers to the right side of the patient's mouth while the fingertips are in constant contact with the epiglottis. Continue the procedure as described above.

Some may be concerned their fingers are not long enough to palpate the epiglottis. Push the soft tissue in the right angle of the patient's mouth posteriorly while inserting your fingers posteriorly in their mouth. This will allow your fingers to reach more posteriorly.

This technique can be used in patients of all ages, including neonates.11,12 Use only the index finger of little finger when performing this procedure in young children. Use the appropriate size suction catheter or endotracheal tube as would be used to orally intubate the child. Do not insert the catheter or endotracheal tube if the child is breathing using this technique or their vocal cords can be damaged.

The placement of an endotracheal tube should be followed by an assessment to ensure its proper positioning (Chapter 12). This includes visual inspection of chest rise and lack of abdominal movement with ventilation, fogging in the endotracheal tube for at least six breaths, auscultation, and end-tidal CO2 monitoring. This should be followed by a chest X-ray to confirm proper positioning of the endotracheal tube within the trachea.

The steps of ensuring proper placement of the endotracheal tube and securing the tube are the same as for any patient who has undergone orotracheal intubation (Chapter 11).

No significant complications to the patient have been identified with digital intubation. One study involving a small number of cadavers found that digital intubation predisposes to left mainstem intubation.9 The investigators concluded that decreased right-sided breath sounds after tactile intubation may represent an easily corrected left mainstem intubation rather than other pathology. An awake or semiconscious patient may gag, with subsequent vomiting and aspiration and injury to the intubator's fingers. For added safety, insert a bite block between the patient's molars if its placement still allows enough space in the patient's mouth for two fingers and the endotracheal tube. The possibility of esophageal intubation is significant, especially if the intubator has small fingers or the airway is anterior. Hypoxemia can result from numerous attempts at intubation without any intervening ventilations. The endotracheal tube should be inserted gently to prevent traumatic injury to the patient's hypopharynx, vocal cords, or trachea.6

Digital (tactile) intubation remains a viable alternative technique for management of the airway. Every Emergency Physician should become familiar with this technique. It is a rapid and safe method to intubate a patient. It is an ideal method for intubating a comatose or paralyzed patient if the upper airway cannot be visualized because of trauma, secretions, or blood. Digital intubation should also be considered when intubating the patient with a known or suspected cervical spine fracture, since this technique requires minimal head and neck movement. It is also a viable method for out-of-hospital intubation.