Blind Placement of an ET Tube
The technique of blind nasotracheal intubation was first described by Magill in 1930. The technique essentially remains the same with some modifications to increase the success rate and limit complications. This technique is technically more difficult than the placement under direct vision described below. Its major advantages are that the patient's mouth does not have to be opened and minimal to no cervical spine movement is required. This procedure may be performed while the patient is sitting or supine. Prepare the patient as mentioned previously.
Stand to the right side of the patient's bed and facing them. Insert the ET tube into the nostril with the bevel facing the septum (Figures 22-1 and 22-2A). If the patient's right nostril is being used, insert the ET tube concave side down (Figure 22-1A). If the patient's left nostril is being used, insert the ET tube concave side up (Figure 22-1B). Advance the ET tube with gentle pressure along the nasal floor to pass it through the nasal cavity (Figure 22-2B). If any resistance is felt, slightly withdraw the ET tube. Readvance the tube with a slight twisting motion to bypass the obstruction. If resistance is still met, withdraw the ET tube, prepare the other nostril, and insert the tube into the other nostril.
Insertion of the nasotracheal tube. The bevel of the ET tube should face the septum. A. Placement in the right nostril with the concave side of the tube downward. B. Placement in the left nostril with the concave side upward. When the tip of the tube enters the nasopharynx, rotate it 180°.
Blind nasotracheal placement. A. The nasotracheal tube is placed within the nasal cavity. B. The tube is advanced along the floor of the nasal cavity and into the nasopharynx. C. The tube is advanced into the laryngopharynx. D. At the start of inspiration, the tube is advanced through the vocal cords and into the trachea.
When the ET tube is inserted approximately 5 to 7 cm, the tip will be past the choana and in the nasopharynx (Figure 22-2B). Continue advancing the ET tube as resistance is met while the tube makes a 90° change of direction into the oropharynx. A slight twisting motion may be required to advance the ET tube. A loss of resistance signifies that the ET tube has made the curve. Stop advancing the ET tube and rotate it so that the tube's natural curve is concave upward and in the same curvature of the airway. If the ET tube will not curve from the nasopharynx into the oropharynx, several options are available. These include trying the other nostril, using an ET tube 0.5 mm smaller and reattempting intubation through the original nostril, or using an Endotrol tube (described in the next section).
Advance the ET tube through the oropharynx and into the laryngopharynx (Figure 22-2C). Listen for breath sounds through the proximal end of the ET tube while advancing it. The breath sounds and air movement will be maximal when the tip of the ET tube is just above the glottis. As soon as an exhalation is heard, the patient will take a breath and advance the ET tube. The vocal cords are opened their widest during inspiration, and this will facilitate passage of the ET tube.
The patient will often cough or gag as the ET tube traverses the vocal cords. At this point, breath sounds should be audible from the proximal end of the ET tube and it should fog with each breath. If the patient is able to groan or speak, the esophagus has been intubated. Withdraw the ET tube and reinsert it during inspiration. The application of posteriorly applied pressure on the trachea (Sellick's maneuver) will occlude the esophagus and may allow easier ET intubation.
If resistance to the advancement of the ET tube is felt, it may be caught in the hypopharynx. Common sites for the tip of the ET tube to get caught are the arytenoid cartilage, piriform sinus, vallecula, and the vocal cords. Withdraw the ET tube 3 to 4 cm, slightly rotate the ET tube, and readvance it.
Inflate the ET tube cuff. Confirmation of ET tube placement should be assessed by auscultating both lungs while ventilating the patient with a bag-valve device through the nasotracheal tube. Adjust the position of the tube until both lungs are being ventilated equally and secure the tube (Figure 22-2D). Continue to ventilate the patient.
Blind Placement of the Endotrol Tube
The indications, contraindications, and patient preparation are the same as described above. The Endotrol tube is an ET tube whose tip can be controlled. It looks like a cuffed ET tube but has a plastic ligature along the inner side that is connected to a ring on the proximal end of the ET tube (Figure 22-3). Pulling of the ring exerts tension on the plastic ligature, leading to an increase in the curvature of the tip of the ET tube. This will project the tip anteriorly and inferiorly (Figure 22-4). The procedure for inserting the Endotrol tube is the same as that for inserting an ET tube. Changing the curvature of the tip will aid in passage of the tube from the nasopharynx to the oropharynx and from the hypopharynx into the trachea. If the ring is sitting firmly against the nares after intubation, the tip of the tube may be exerting continuous pressure on the anterior tracheal mucosa. Cut the ligature and remove the ring.
The Endotrol endotracheal tube. The curvature can be changed by pulling on the ring to facilitate intubation.
Blind nasotracheal placement of an Endotrol tube. Tension exerted on the ring of the tube causes the curvature of the tube to increase (arrow).
Placement under Direct Vision
The technique begins with nasotracheal intubation, followed by direct laryngoscopy. The placement of a nasotracheal tube using direct visualization must be performed with the patient supine. The indications and precautions are similar to those for orotracheal intubation (Chapter 11). This method should be considered in the event of an oral injury that renders an orotracheal tube a nuisance or if blind nasal intubation is unsuccessful.
This procedure is initially performed as previously described. Once the tube is inserted into the hypopharynx, direct laryngoscopy is performed. Using the left hand, grasp the laryngoscope and insert the blade. Visualize the patient's epiglottis and vocal cords as well as the ET tube. Using a Magill forceps with the right hand, grasp the ET tube just above the cuff (Figure 22-5). Never grasp the cuff, as it is delicate and can easily be damaged by the Magill forceps. Have an assistant grasp the proximal end of the ET tube and gently advance it while the physician simultaneously guides the tip through the vocal cords (Figure 22-5). Remove the Magill forceps and the laryngoscope. Inflate the cuff, secure the tube, and ventilate the patient.
Nasotracheal intubation under direct visualization.
Blind Digital Nasotracheal Intubation
A technique was developed that combines blind nasotracheal intubation and digital orotracheal intubation.12 This technique starts with the procedure of blind nasotracheal intubation. If not successful, insert the index and middle fingers of the nondominant hand into the patient's mouth. Slide these fingers posteriorly over the tongue to palpate the epiglottis. Grasp the tip of the ET tube between the two fingers (Figure 22-6A). Pull the ET tube anteriorly and behind the epiglottis (Figure 22-6A). Use the nondominant hand to advance the ET tube further into the patient's nose, thus advancing the tip into the trachea (Figure 22-6B).
Blind digital nasotracheal intubation. A. The ET tube is grasped with the fingertips and pulled anteriorly (arrow) behind the epiglottis. B. The ET tube is advanced into the trachea.