John E. Fiadjoe, MD
Assistant Professor of Anesthesiology and Critical Care
Hospital of the University of Pennsylvania
The Children’s Hospital of Philadelphia
Madhankumar Sathyamoorthy, MBBS, MS
Department of Anesthesiology
University of Mississippi Medical Center
Vikram Patel, MD
Assistant Professor of Clinical Anesthesiology
Division of Pediatric Anesthesiology
Vanderbilt University Medical Center
Difficult tracheal intubation (TI) in children presents unique challenges for anesthesiologists. These children have limited pulmonary reserve and are prone to laryngospasm and airway activation.
Small children are uncooperative with awake intubation and so usually require deep sedation or general anesthesia. Given this background, a thorough knowledge of pediatric airway management techniques is critical in order to minimize complications and encourage successful TI outcomes.
This article highlights “secret” techniques for first-pass success with TI. These techniques are not secrets in the traditional sense of the word, however, but many of these techniques are not ubiquitously practiced and may help achieve first-pass TI in an efficient and safe way. First-pass TI is important because multiple intubation attempts have been associated with complications in adult tracheal intubations, pediatric intubations in the ICU, and in children with difficult TI.1,2
Secret #1 The Modified Nasopharyngeal Airway
The modified nasopharyngeal airway (MNA) is simply an airway with a 15-mm adapter inserted into the flared end (Figure 1). It is easily put together in the operating room but is also commercially available. The appropriate length of the MNA should extend from the lateral nostril to the tragus of the ear.
Administering oxygen and inhaled anesthetic through the MNA is a useful technique to minimize hypoxemia and maintain anesthetic depth. After induction of anesthesia, a 5-second jaw thrust is a good way to assess anesthetic depth. A lack of response (ie, movement, tachycardia, tachypnea, or cough) indicates that conditions are optimal for airway manipulation. The MNA is inserted after applying oxymetazoline into the nose.
The adapter at the end of the MNA is connected to the anesthesia circuit, allowing the patient to receive inhaled anesthetic and oxygen throughout the intubation. The MNA is particularly advantageous for fiber-optic intubation through the contralateral nostril.3 The tip of an appropriately sized nasopharyngeal airway often sits directly above the glottic opening. If the MNA is visualized during fiber-optic intubation, it can be followed as a guide to the glottis, even when soft tissue obstruction occurs.
Secret #2 Continuous Ventilation Through The Supraglottic Airway
The supraglottic airway (SGA) is an indispensible adjunct in airway management. It is often an effective rescue ventilation technique when face mask ventilation is difficult. Learning to intubate the trachea through an SGA is a basic skill for all anesthesiologists; it requires several discrete steps and can be complicated by the inability to fit the pilot balloon cuff of the selected tracheal tube into the SGA or dislodged tracheal tube when the SGA is removed.
Adding continuous oxygenation or ventilation during SGA intubation provides the operator with more time to secure the airway and manage any technical difficulties that may occur. The laryngoscopist should confirm that the selected tracheal tube and its pilot balloon pass completely through the SGA.
The air-Q (Mercury Medical) SGA accommodates cuffed pediatric tubes with little resistance (Figure 2). The 15-mm tracheal tube adapter should be removed and then reinserted loosely (Figure 3) so it can be readily removed when the SGA is withdrawn out of the pharynx. The tracheal tube is then inserted into the airway tube of the SGA, and the tracheal tube cuff is inflated to create a tight seal. Liberal lubrication of the airway tube of the SGA and outer aspect of the tracheal tube is helpful in passing the tracheal tube through the SGA. A perforated swivel adapter is placed on the end of the tracheal tube (Figure 4).
The SGA, tracheal tube, and swivel adapter unit is inserted after the child is anesthetized and connected to the anesthesia circuit. This technique allows the delivery of oxygen and inhaled agent during fiber-optic intubation through the swivel adapter. The fiber-optic bronchoscope is passed through the swivel adapter and in situ tracheal tube into the trachea.
Once the fiber-optic bronchoscope is placed in the trachea, the tracheal tube cuff is then deflated and the tube advanced gently into the trachea. Tracheal location is confirmed while the fiber-optic bronchoscope is being withdrawn from the SGA. After confirming successful TI, removing the SGA while maintaining the tube in the trachea is a delicate step. The ideal approach is to use laryngeal/long alligator forceps or a commercially available tube stabilizer to maintain the tracheal tube position while removing the SGA (Figures 5 and 6).
A second tube loaded on the bronchoscope can be used as a stabilizer during removal of the SGA. The SGA can be left in situ in precarious clinical situations.
Secret #3 How To Deal With the Tracheal Tube Pilot Balloon Cuff That Will Not Fit Through the SGA
In many smaller-sized SGAs, the pilot balloon cuff of cuffed tracheal tubes may not pass through the SGA airway tube. If this occurs, the pilot balloon can be cut to allow intubation through the SGA (Figure 7). It can then be reconstructed post-intubation by inserting an angiocatheter into the cut end and applying a one-way valve on the end of the angiocatheter (Figure 8). This allows for both the reinflation of the cuff and measurement of the cuff pressure. An epidural clamp connector applied to the cut end of the inflation line is equally as effective as the angiocatheter technique (Figure 9).4
Secret #4 How To Deal With a Hung Tracheal Tube During Fiber-Optic Intubation
Hang-up of the tracheal tube during fiber-optic intubation is a common problem during pediatric intubations. It is more likely when there is a large discrepancy between the tube size and the fiber-optic scope size (Figure 10). Every anesthesiologist should develop a series of routine steps to address this problem. There are at least 5 common steps that may help.
- Rotate the tube
A tracheal tube loaded on a bronchoscope has a natural position usually with the Murphy eye to the right of the operator when standing at the head of the bed (Figure 11). This may cause the tracheal tube to hang-up on the patient’s right arytenoid when advanced. If this occurs, the tube should be withdrawn and rotated 90 degrees counterclockwise to reduce the chance of hang-up. Routinely advancing the tube with the bevel facing posteriorly will reduce the incidence of hang-up (Figure 12).
- External laryngeal manipulation
Manipulating the glottis externally can allow the tube to pass into the trachea if hang-up occurs. Routinely palpating the larynx during tracheal tube placement provides tactile feedback as to whether the tube hangs up or enters the trachea, and this maneuver also provides a solution (laryngeal manipulation) when hang-up does occur. This is one of the most effective methods for addressing a hung tube during advancement over a fiber-optic bronchoscope.
- Direct laryngoscopy or video laryngoscopy
Direct laryngoscopy or video laryngoscopy (VL) performed during advancement of the tracheal tube off the fiber-optic bronchoscope may reduce hang-up by reducing soft tissue obstruction.
- Fiber-optic bronchoscope withdrawal
A key limitation of fiber-optic intubation is that passage of the breathing tube is blind. A technique unique to pediatric intubations with small tubes is the ability to withdraw the scope into the distal end of the tracheal tube in order to manipulate the tip of the tracheal tube around the cause of obstruction. The bronchoscope is withdrawn until it sits just inside the breathing tube. Manipulation of the bronchoscope directs the tube and allows the operator to visualize and circumnavigate the cause of the obstruction.
- Parker tube
The Parker tube (Parker Hannifin) has a curved tip that hugs the fiber-optic bronchoscope more effectively than standard tracheal tubes and readily slides into the trachea. If a large discrepancy exists between the scope size and tracheal tube size, using the Parker tube may reduce the chance of hang-up.
Secret #5 Combine Video Laryngoscopy With Fiber-Optic Bronchoscopy
Video laryngoscopy is becoming routine in airway management. Although glottic exposure is usually adequate with VL, placement of the tracheal tube may remain challenging. Fiber-optic intubation requires good kinesthetic skill to manipulate the scope into the trachea. Combining VL with fiber-optic bronchoscopy may facilitate placement of the bronchoscope into the trachea, since the relative location of the bronchoscope to the glottic opening is visualized with VL, while the view from the distal tip is seen through the bronchoscope. Placing the fiber-optic bronchoscope into the trachea and then advancing the tracheal tube under visualization with the VL converts the blind insertion of the tracheal tube to a visualized technique. In this way, hang-up of the tube is immediately recognized and appropriate corrective maneuvers can be performed under continuous visual guidance.
Secret #6 Use Apneic Oxygenation Techniques
Apneic oxygenation has been shown to delay desaturation in adults and older children. Apneic oxygenation can be achieved with a standard laryngoscope or VL with an integrated oxygen delivery side port or through a MNA, as described earlier. The airway should be kept open in order for effective bulk flow of oxygen to occur.
One study showed that after adequate preoxygenation, apneic oxygenation could maintain adequate saturation in children for 10 minutes and in infants for 2 minutes.5 Another report describes using a nasal cannula with 6 to 8 L/min oxygen flow in infants with pyloric stenosis to delay desaturation during rapid sequence intubation.6
Although these techniques are advantageous in apneic children, they are likely more efficacious in spontaneously ventilating patients. Advantages of spontaneous ventilation in difficult pediatric TI include better airway tone and less obstruction, delayed hypoxemia, and easier fiber-optic intubation. Fiber-optic intubation may be easier because spontaneously ventilating children often have visible bubbles in their airway from exhaled gases. When the visualized anatomy is poor, following these bubbles leads the bronchoscopist directly to the glottic opening.
Secret #7 How To Rescue a Failed Nasal VL Intubation With a Nasogastric Tube
Nasal intubation with VL can be challenging because, although the glottis is readily visualized, it may be difficult to direct the breathing tube into the glottis with Magill forceps. There is also a risk for rupturing the tracheal tube cuff if it is handled with Magill forceps. Even when the tube is successfully placed between the vocal cords, it may still hang up on the anterior tracheal wall and fail to pass into the mid-trachea.
A simple technique in support of nasal intubation is to place a small lubricated nasogastric tube through the tracheal tube, which is then inserted through the patient’s nose into the posterior pharynx. The nasogastric tube serves as a guide for the breathing tube through the nose and can be carefully inserted into the trachea using the forceps. The tube is then advanced over the nasogastric tube into the trachea. Although the tip of the nasogastric tube is blunt, it should not be inserted distally into the lung to avoid potential airway injury.
Difficult intubation remains a cause of significant morbidity and mortality in children. The above techniques can facilitate airway management in children. These skills can only be mastered with deliberate practice in patients with normal airways.
Aristotle is noted to have said, “Excellence is an art won by training and habituation. We do not act rightly because we have virtue or excellence, but we rather have those because we have acted rightly. We are what we repeatedly do. Excellence, then, is not an act, but a habit.”
- Graciano AL, Tamburro R, Thompson AE, et al. Incidence and associated factors of difficult tracheal intubations in pediatric ICUs: a report from National Emergency Airway Registry for Children: NEAR4KIDS.Intensive Care Med. 2014;40(11):1659-1669.
- Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts.Anesth Analg. 2004;99(2):607-613.
- Holm-Knudsen R, Eriksen K, Rasmussen LS. Using a nasopharyngeal airway during fiberoptic intubation in small children with a difficult airway.Paediatr Anaesth. 2005;15(10):839-845.
- Kovatsis PG, Fiadjoe JE, Stricker PA. Simple, reliable replacement of pilot balloons for a variety of clinical situations.Paediatr Anaesth. 2010;20(6):490-494.
- Cook TM, Wolf AR, Henderson Changes in blood-gas tensions during apnoeic oxygenation in paediatric patients.Br J Anaesth. 1998;81(3):338-342.
- Bhagwan SD. Levitan’s no desat with nasal cannula for infants with pyloric stenosis requiring intubation.Paediatr Anaesth. 2013;23(3):297-298.