29: Endotracheal Intubation and Extubation

1. Provide mechanical respiratory support.

2. Obtain aspirates for culture.

3. Assist in bronchopulmonary hygiene (“pulmonary toilet”).

4. Alleviate upper airway obstruction (subglottic stenosis).

5. Clear the trachea of meconium.

6. Perform selective bronchial ventilation.

7. Assist in the management of congenital diaphragmatic hernia (to avoid bowel distention).

8. Administer medications (“NEAL” or “LANE” see Section III.O) in the emergency setting while intravenous access is established.

9. Administration of surfactant.

10. Management of apnea.

Correct endotracheal tube (ETT) and suction catheter (Table 29–1), a pediatric laryngoscope handle with a Miller blade (“00” blade for extremely preterm infants, “0” blade for preterm infants, “1” blade for full-term infants; straight blades [Miller blades] are preferred over curved blades [Macintosh blade] because of better visualization), an ETT adapter, a suction apparatus, suction catheters, tape, scissors, tincture of benzoin, a malleable stylet (optional), personal protection equipment, bag-and-mask apparatus with 100% oxygen, and pressure manometer should be available at the bedside. The mechanical ventilator should be checked and ready. Monitoring with electrocardiogram and pulse oximetry is essential if time permits. A colorimetric device or capnograph to confirm the position of the tube. Suctioning equipment and catheters.

1. Orotracheal versus nasotracheal intubation

   1. Orotracheal intubation. More commonly performed emergently and is described here. It is easier and quicker than nasotracheal intubation. The orotracheal tube should be precut to eliminate dead space (cut to 15 cm).

   2. Nasotracheal intubation. More commonly performed in the elective setting or if anatomy precludes the oral route. Nasotracheal intubation can be used in overly active infants or in those infants who have copious secretions. It offers tube stability but can be associated with an increase in postextubation atelectasis and a risk of nasal damage. In nasotracheal intubation the procedure is the same except the lubricated nasotracheal tube is passed into the nostril, then pharynx and into cords following to the back of the throat. Small doses of 2% lidocaine gel can be used.

   3. Cochrane review. Did not find any differences in the effect of nasal versus oral intubation.

2. Pain/premedication

   1. Premedication is not necessary in the case of an emergency intubation in the delivery room or after an acute deterioration in a neonatal intensive care unit (NICU). It is also not necessary in some cases of infants with upper airway anomalies (such as Pierre Robin sequence).

   2. If IV access is not available, the IM route should be considered.

   3. Premedication. Many intubations require more than one attempt and take longer than the recommended time frame; therefore, premedication can improve intubation and also alleviate the pain associated with it. Premedication for nonemergency intubation in the neonate is safer and more effective than when awake, but the ideal combination of premedication has not been established. Preferred medications are with a rapid onset and short duration of action. One preferred sequence is as follows:

      1. Administer oxygen.

      2. Vagolytic agent to prevent bradycardia. Atropine preferred.

      3. Analgesic (fentanyl preferred) and/or sedative/hypnotic. None preferred.

      4. Muscle relaxant. Vecuronium or rocuronium preferred.

   4. Because optimal protocols and medications have not been established, each unit should adopt its own pain and premedication protocols. See Table 29–2 for a listing of elective intubation medications reviewed by the American Academy of Pediatrics (AAP). Key premedication points:

      1. Do not use a sedative without an analgesic agent.

      2. Do not use a muscle relaxant without an analgesic agent.

      3. Analgesic or anesthetic dose of a hypnotic drug should be given.

      4. Vagolytic and muscle relaxants (rapid onset) should also be considered.

   5. Rapid sequence intubation (RSI). Involves premedication prior to intubation with atropine, a sedative, and a neuromuscular blocker. It is commonly used in the emergency department for rapid intubation. When RSI is used in neonates, there is better visualization of the airway, no movement from the infant, and intubation is quicker with lesser attempts. One recommendation: atropine IV push (0.01–0.03 mg/kg, minimum dose 0.1 mg), fentanyl (2–3 mcg/kg per dose), and lastly vercuronium (0.1 mg/kg per dose). Further research is needed before definite recommendations can be made on using RSI in the neonate.

3. Confirm that the laryngoscope light source is working before beginning the procedure. Place the stylet (if used) in the endotracheal tube (ETT). Malleable stylets are optional but may help guide the tube into position more efficiently. Be sure the tip of the stylet does not protrude out of the end of the ETT. The stylet should be 1–2 cm proximal to the distal end of the ETT.

4. Place the infant in the “sniffing position” (with the neck slightly extended); a small roll behind the neck may help with positioning. Hyperextension of the neck in infants may cause the trachea to collapse. It displaces the cords anteriorly and makes it difficult to pass the ETT. The infant's head should be at the same level as the operator.

5. Cautiously suction the oropharynx as needed to make the landmarks clearly visible.

6. Preoxygenate the infant with a bag-and-mask device, and monitor the heart rate, color, and pulse oximeter. To limit hypoxia, limit each intubation attempt to <20 seconds before reoxygenation. Infants frequently deteriorate during an intubation attempt.

7. Hold the laryngoscope with your left hand. Insert the scope into the right side of the mouth, and sweep the tongue to the left side. Some practitioners move the tongue to the left by using the index finger of the right hand placed alongside the head. To perform this maneuver, stabilize the head and hold the mouth open.

8. Advance the blade a few millimetres, passing it beneath the epiglottis.

9. Lift the blade vertically to elevate the epiglottis and visualize the glottis (Figure 29–1). Note: The purpose of the laryngoscope is to lift the epiglottis vertically, not to pry it open. To better visualize the vocal cords, an assistant may place gentle external pressure on the thyroid cartilage. If the cords are together, wait for them to open (never force a tube between closed cords). Do not touch the closed cords as this may cause spasm.

10. Pass the ETT along the right side of the mouth and down past the vocal cords during inspiration. Advance the tube only 2–2.5 cm into the trachea to avoid placement in the right main stem bronchus (no more than 1–2 cm below the vocal cords). If a stylet was used it should be removed gently while the tube is held in position. If the tube is needed for suction (as in meconium aspiration), connect to a meconium aspirator.

11. Multiple ETT depths of insertion methods are described:

    1. 7-8-9 rule (Tochen rule). The depth of ETT insertion in centimeters (“tip to lip”) is estimated as 6 plus the weight in kilograms. Tape the ETT at the lip when the tube has been advanced 7 cm in a 1-kg infant, 8 cm in a 2-kg infant, 9 cm in a 3-kg infant, or 10 cm in a 4-kg infant (“1, 2, 3, 4, 7, 8, 9, 10”). Do not use this in infants <750 g (overestimates the depth of insertion) or in infants with severe neck or orofacial deformities. Infants weighing <750 g may only require a 6-cm insertion (see Table 29–1).

    2. ETT length based on gestation-based guidelines. ETT length is more related to gestation in a linear manner than to birthweight. Using gestation-based guidelines are associated with a decrease in uneven lung expansion and a decrease in the number of tubes that need to be repositioned. See Table 29–3.

    3. Nasal tragus length (NTL) and sternal length (STL). One method that allows length assessment in ∽10 seconds and does not require weight is the NTL (base of the nasal septum to the tragus of the ear); the other method is the STL (suprasternal notch to the tip of the xiphoid process).

       1. Orotracheal route. NTL or STL plus 1.

       2. Nasotracheal route. NTL or STL plus 2.

12. Confirm the position of the tube immediately after insertion. Detection of exhaled carbon dioxide plus clinical assessment are the most reliable initial methods to confirm placement of a tracheal tube in a neonate.

    1. Auscultation. The resuscitation bag is attached to the tube using the adapter, and an assistant provides mechanical breaths while the operator listens for equal breath sounds on both sides of the chest. Some recommend the stethoscope laterally and high on the axilla of the chest. Auscultate the stomach to be certain that the esophagus was not intubated. Caution is necessary as breath sounds heard over the anterior part of the chest can come from the stomach or esophagus. If correctly intubated there should be an increase in heart rate and color. Breath sounds are audible over lung fields and are absent in the stomach. There should be no gastric distension and vapor condensing on the inside of the tube during exhalation.

    2. CO₂ detectors. To confirm ETT position.

       1. Colorimetric device. Changes color in the presence of CO₂ and is the most commonly used device. End tidal carbon dioxide detectors connected to the ETT are commercially available that rapidly confirm proper endotracheal placement. One such device (Pedi-Cap CO₂ detector, Nellcor) displays violet in the absence of CO₂ and yellow means presence of CO₂ (tube in trachea).

       2. Capnographs. These have a special electrode at the ETT connector, and a waveform shows oscillation with each breath if the tube is in the correct place.

       3. Limitations of ETT CO₂ detectors. With some cyanotic congenital heart disease, they may underestimate the true arterial CO₂ level. If the cardiac output is low or absent and there is no heartbeat, the CO₂ monitor may not change color because not enough CO₂ is exhaled to detect. Any acidic substance (gastric acid, endotracheal epinephrine) can contaminate the colorimetric device and cause a false-positive result.

13. Paint the skin with tincture of benzoin and tape the tube securely in place. A Neofit tube grip (Ackrad Laboratories, Cranford, NJ) eliminates the need for tape use and provides stabilization. It fits tube sizes 2.5–4.0 mm. A Neobar (Valencia, CA) can also be used.

14. After the ETT is secured, obtain a chest radiograph to confirm proper placement of the tube. Figure 11–7 shows proper placement of a neonatal ETT. Some sources indicate that the ETT tip should be placed at the level of the body of the first thoracic vertebra, and to not use the medial end of the clavicles (most common reference point) as their position may be variable. Others state that the ETT tip should be placed 2 cm above carina.

15. Certain emergency medications can be given through the ETT. These medications are lidocaine, atropine, naloxone, and epinephrine. These can be remembered by the mnemonic “LANE” or “NEAL.” Epinephrine given by intravascular route is recommended as the most effective route, since absorption by the lungs is slow and unpredictable; however, it can be given by the ETT route while the IV is being started. A higher dose of epinephrine (0.5–1 mL/kg of 1:10,000) is necessary even though studies do not validate the safety of this. There are no studies confirming that endotracheal naloxone is effective.

1. The decision to remove an endotracheal tube is a complex clinical decision. Issues surrounding ventilatory support are discussed in Chapter 8. When adequate ventilation is maintained with minimal settings, extubation is attempted. Manage postextubation atelectasis intensively with chest physiotherapy.

2. Use of medications prior to extubation

   1. Dexamethasone use is controversial

      1. Stridor. Some advocate systemic dexamethasone given before and after extubation to reduce the incidence of stridor. A Cochrane review states that using corticosteroids in neonates to prevent or treat stridor after extubation is not effective.

      2. Reintubation risk. Dexamethasone IV given prior to extubation reduces the need for reintubation in high-risk neonates. A Cochrane review states that it is best to use in infants at risk (repeated and prolonged intubations) for airway edema and obstruction.

      3. Systemic corticosteroids. Early corticosteroid therapy (first 2 weeks after birth) reduced the risk of BPD/CLD and shortened the time to extubation. Steroid therapy after 3 weeks promoted earlier extubation. Because of long-term studies showing poor neurodevelopment, use is not recommended routinely. Cochrane review states steroid therapy should be limited until further studies are done.

   2. Methylxanthines used prophylactically (eg, caffeine) increases the chance of successful extubation of preterm infants within 1 week of life. The caffeine group had lower rates of patent ductus arteriosus ligation, cerebral palsy, death, bronchopulmonary dysplasia/chronic lung disease (BPD/CLD), or major disability at 18–21 months. The majority of preterm infants are given caffeine before extubation and are maintained on this medication while on nasal continuous positive airway pressure (NCPAP) or nasal ventilation.

   3. Other medications. Cochrane review states there is not enough evidence to support the routine use of prophylactic doxapram and there is no evidence for or against the use of nebulized racemic epinephrine.

3. Extubation procedure

   1. Perform chest physiotherapy and suction.

   2. Remove tape and any devices that are holding the ETT in place.

   3. Remove the tube. Best to use your own unit's recommendation on how and when to remove the tube. Recommendations vary:

      1. Give positive pressure inspiration while slowly removing the tube.

      2. Suction, give positive pressure breaths, remove the ETT.

      3. Using manual ventilation, give the infant a sigh breath, and withdraw the tube during exhalation.

   4. Chest physiotherapy. Cochrane review found that fewer babies had to go back on ventilator support when chest physiotherapy postextubation was used.

4. Other postextubation procedures. Level of respiratory support varies and depends on the clinical status of the patient. (See also Chapter 8.) Possibilities include:

   1. Supplemental oxygen by hood or high-flow nasal cannula (HFNC) >3–6 L/min. Limit flows in extremely low birthweight (ELBW) infants to less than 6 L/min (controversial). High-flow nasal cannula may be associated with a higher rate of reintubation than NCPAP in preterm infants. Cochrane review states that there is not enough evidence to use HFNC as a form of respiratory support in preterm infants.

   2. Nasal continuous positive airway pressure (NCPAP). Cochrane review found that NCPAP reduced the incidence of apnea, respiratory acidosis, and increased oxygen requirements after extubation in preterm infants. Cochrane review states that binasal prongs are more effective than single prongs after weaning in reducing reintubation. NCPAP is used with a nasal interface such as nasal prongs (eg, Hudson type). Other forms of postextubation support are bubble CPAP, and N-BiPAP (nasal biphasic positive airway pressure).

   3. Nasal ventilation. Nasal intermittent positive pressure (NIPPV) is better than NCPAP in preventing reintubation on extubated infants. Both NIPPV and synchronized nasal intermittent positive pressure ventilation (SNIPPV) seem to be equally effective.

5. Observe for atelectasis. If the infant has an increasing oxygen requirement and signs of respiratory distress a chest radiograph should be obtained.

1. Hypoxia, apnea, hypoventilation, and bradycardia can all occur during the intubation process. This can be secondary to a prolonged attempt or vagal reflex.

2. Hypopharyngeal or tracheal perforation/rupture and trauma. Tracheal perforation is a rare complication requiring surgical intervention and is prevented by careful use of the laryngoscope and the ETT. Hemorrhage, edema of the larynx, and injury to the vocal cord can all occur. Tracheal injury usually presents with rapid occurrence of subcutaneous emphysema, pneumomediastinum, and respiratory failure. Contusions of the gums, tongue, and airway can occur.

3. Esophageal perforation. Usually caused by traumatic intubation, and treatment depends on the degree of perforation. Most injuries can be managed conservatively by use of parenteral nutrition until the leak seals, use of broad-spectrum antibiotics, and observation for signs of infection. A barium swallow contrast study may be necessary after several weeks to evaluate healing or rule out stricture formation.

4. Laryngeal edema. Usually seen after extubation and may cause respiratory distress. A short course of steroids (eg, dexamethasone) can be given intravenously before and just after extubation. However, systemic dexamethasone has no effect in reducing acute postextubation stridor in neonates.

5. Improper tube positioning (esophageal intubation, right main stem bronchus). Signs of esophageal intubation include poor chest movement, no breath sounds heard, zero mist in the tube, continued cyanosis, gastric distension, and air heard over the stomach. Signs of right main stem bronchus intubation include breath sounds heard over the right chest and none heard over the left, and no improvement in color. ETT in right main stem bronchus causes overventilation of the right lung and hypoventilation or atelectasis of the left lung. If the tube is in the right main stem bronchus, it needs to be pulled back to the position where the breath sounds on both sides of the chest become equal.

6. Tube obstruction or kinking. Try suctioning or possibly reintubation.

7. Infection. Pneumonia and trachea-bronchitis can occur.

8. Palatal/alveolar grooves. Palatal and alveolar grooves are usually seen in cases of long-term intubation and typically resolve with time.

9. Subglottic stenosis. Subglottic stenosis is most often associated with long-term (>3–4 weeks') endotracheal intubation. It is the most serious long-term complication and is secondary to posttraumatic fibrosis of the infant larynx. Surgical correction is usually necessary. With prolonged intubation, consideration may be given to surgical tracheostomy to help prevent stenosis.

10. Other complications. Aspiration, atelectasis, pneumothorax, increased intracranial pressure, and hypertension can all occur.