Chapter 29. Airway Management of a Patient in a Halo Jacket Who Has Developed a Tracheal Tube Cuff Leak

A 52-year-old worker of normal body habitus was injured in a fall from approximately 15 ft (5 m) of height. He sustained fractures to the vertebral bodies of C3 and C4, as well as a C5 transverse process fracture. He was retrieved by an ambulance team and admitted to the hospital in a hemodynamically stable condition. His breathing on admission was noted to be normal, albeit with decreased air entry to the right side. An infiltrate on chest x-ray was consistent with aspiration. Neurologically, the patient was awake and alert. He had evidence of a Brown-Sequard syndrome with an almost complete paralysis of his left limbs and a sensory deficit on his right.

The patient's neck had been placed in a rigid cervical collar at the scene and he was given oxygen via a face mask. Tracheal intubation was performed uneventfully by elective bronchoscopic intubation in the operating room (OR) for dorsal fixation of his C-spine. Completion of internal fixation by ventral stabilization was planned at a later date and in the interim the patient was placed in a halo frame for external fixation (Figure 29-1). He was then transferred to the intensive care unit (ICU) intubated and ventilated, as his oxygen requirements had increased to 60%. An aspiration pneumonia was suspected and he was sedated and ventilated according to a lung protective ventilation strategy.

Past medical history included hypertension, GERD, and a question of significant alcohol consumption.

By day 3 of his ICU admission, the pulmonary situation had improved marginally. He still required a FiO2 of 0.45 and was breathing spontaneously with a pressure support of 12 cm H2O and positive end-expiratory pressure (PEEP) of 10 cm H2O. Attempts to wean the pressure support had failed at that point, resulting in tachypnea and oxygen desaturation. Thick purulent sputum was being suctioned from his endotracheal tube (ETT) twice per shift, and he was receiving empiric antibiotics to treat his presumed pneumonia.

Agitation had become a major issue, thought to be delirium tremens secondary to alcohol withdrawal. A cranial CT had ruled out posttraumatic intracerebral hemorrhage as the underlying cause. The patient was difficult to manage, often requiring more than one nurse at the bedside, and he had tried to remove lines and ETT with his functioning hand. For this reason he required passive restraints and sedation.

On day 4, the bedside nurse called urgently to report that the patient in his agitation had bitten off the pilot line to the ETT cuff. The cuff was leaking and the patient was being inadequately oxygenated, with a drop of SpO2 to 87%.

29.2.1. Medical Considerations

29.2.1.1. Is the Patient at Acute Risk of Suffering Harm?

Hemodynamics and gas exchange must be included in the assessment of the acute need for emergency treatment. While an SpO2 of 87% is certainly abnormally low, it might not impose an acute danger to the patient on the short term. Two factors are important: whether the patient has organs at risk of hypoperfusion (and thus cellular hypoxia) and if sufficient oxygen carrying capacity exists to compensate for lower oxygen saturation.

Oxygen-carrying capacity (or oxygen delivery) depends on cardiac output, hemoglobin concentration, and hemoglobin oxygen saturation. The patient was slightly anemic (Hgb 110 g/dL), although with an increase in heart rate from 81 to 105 beats per minute following development of the cuff leak, some compensation had occurred by increasing cardiac output to maintain oxygen delivery.

The patient was not known to have coronary artery or cerebrovascular disease; he had no specific risk factors and was thus unlikely to have hypoperfusion of vital organs. As such, a borderline SpO2 could be tolerated for a short period of time.

It was concluded that this patient needed urgent troubleshooting, but not necessarily an emergency ETT exchange, allowing a carefully planned procedure to prevent further harm.

29.2.1.2. Which Are the Management Options for Treatment?

In a prospective multicenter study involving 426 patients, Boulain1 reported that self-extubation occurred in 46 patients (11%), and 18 of these patients did not require reintubation. Therefore, it is necessary to assess the patient's ability to breathe unassisted and determine the need for further ventilatory assistance. While it is possible that a subgroup of self-extubated patients not yet capable of completely breathing on their own may be amenable to noninvasive ventilaton (NIV), this patient's halo frame precluded NIV due to technical constraints.

Indicators for the ability to ventilate include respiratory rate, the patient's work of breathing, and gas exchange. In this patient, an increase in heart and respiratory rate and the decrease in SpO2, combined with clearly visible usage of accessory muscles of respiration indicate the need for further ventilatory support. His respiratory failure was likely multifactorial, including the aspiration pneumonia as well as compromised intercostal and diaphragmatic muscular function due to his high spinal cord injury. As the patient needed further ventilatory assistance, an ETT exchange was indicated.

29.2.2. Airway Considerations

29.2.2.1. What Should Be the Initial Management?

First, the patient should be placed on FiO2 of 1.0 to improve oxygenation. This increased the SpO2 to 91%, which helped to buy some time to adequately prepare for the procedure. Also, even though the leak prevailed, some degree of minute ventilation remained, as not all of the delivered tidal volume escaped and the patient continued spontaneous breathing efforts.

An attempt can be made to reestablish ventilation by fixing the pilot line. However, in this case, the line had multiple tears and could not be fixed.

Alternative approaches in the case of life-threatening hypoxemia should aim to temporarily restore oxygenation until a definitive airway can be placed. The existing tube, if ineffective, can be removed and the patient's respiratory efforts assisted with bag-mask-ventilation. Ventilation can be improved by use of an oropharyngeal airway. However, in most cases, even with a leaky cuff, some ventilation can be maintained by hyperventilating with high flows and respiratory rate (>30 breaths per minute), mimicking high-frequency ventilation.

The high-frequency oscillation (HFO) mode of ventilation can provide sufficient oxygenation even with a cuff leak. Indeed, during routine use of HFO, a cuff leak is sometimes purposefully used to improve ventilation. It is an ideal rescue maneuver in a situation where a patient desaturates and cannot be ventilated by other means. This option could be considered before a leaky tube was removed. HFO would be the preferred technique in this situation if a patient had profound gas exchange impairment, such as ARDS, to be used until arrangements for safe ETT exchange were made.

There should always be alternatives at hand in case the first attempt to reintubate the patient fails following removal of the faulty ETT. These can follow the ASA algorithm for the difficult airway and might include, but are not confined to, smaller ETTs, alternatives to DL, an appropriately sized EGD, and cricothyrotomy equipment. More help should be obtained as a difficult situation such as this can always be better managed with additional medical and nursing staff. Calling for additional expertise is not a sign of incompetence, but of professionalism!

29.2.2.2. How Might the Presence of a Halo Jacket Impact Airway Management?

The presence of a halo jacket can impact all facets of airway management. In this case, the trachea of the patient was first intubated by awake bronchoscopic intubation, and a direct laryngoscopic view had not been assessed thereafter. The halo jacket fixes the head in a neutral position, and prevents any flexion or extension of the neck (Figure 29-1). With direct laryngoscopy (DL), it is likely that at best a Cormack/Lehane (C/L) Grade 3 view will be achieved. Tracheal intubation is more likely to succeed with alternatives to DL, such as flexible or rigid fiber- or video-optic devices (see Chapters 9 and 10). Should intubation fail and the patient require oxygenation by positive pressure ventilation between attempts, BMV could also prove challenging due to decreased head extension, and for the same reason, EGD insertion may be difficult. Finally, cricothyrotomy is usually performed with the head extended, so this can also be expected to be somewhat more difficult in the patient with a halo jacket.

In this agitated and uncooperative patient, it is unlikely that an awake look DL assessment under topical airway anesthesia and light sedation will be an option. Alternative approaches must be considered.

29.2.2.3. What Other Risks Are Inherent in This Situation?

Enteral nutrition imposes an additional risk for aspiration while the airway is unprotected. Enteral feeds should be stopped immediately and the feeding tube suctioned to clear as much gastric content as possible.

An already agitated patient may well get more delirious if ventilatory support suddenly stops and hypoxemia develops. Sedation will also be needed to allow the patient tolerate the tube exchange procedure. On the other hand, should reintubation fail during tube exchange, preservation of spontaneous ventilation will add a margin of safety. When practical, nonpharmacological ways of calming the patient (talk-down and reassurance with the help of additional staff) cannot be overestimated. If needed, short-acting drugs such as propofol are preferred.

The reasons for the patient's continuing need for mechanical ventilation are weakness and pneumonia. Weakness alone as a cause of respiratory failure could be treated by noninvasive ventilation (NIV). However, in this case, severe agitation is a contraindication to NIV and as previously suggested the halo jacket will cause difficulty with its application. Pneumonia on the other hand causes edema, atelectasis, and ventilation-perfusion mismatch, resulting in hypoxemic respiratory failure. To aggravate the situation, the loss of PEEP due to the cuff leak will lead to even more atelectasis formation in unstable regions. Furthermore, functional residual capacity (FRC) will be reduced, increasing the patient's susceptibility to hypoxemia. As the combination of these factors increases the risk of hypoxemia within minutes, tube exchange should not be deferred for long.

Although a leak is clearly audible, other significant alterations of the airway should be anticipated. Mucosal swelling from inflammation and general edema, as well as displacement of tissue from the previous trauma may cause physical impediment to the placement of a new ETT or total obscuring of laryngeal inlet anatomy after the defective tube is removed.

29.3.1. Which Is the Best Strategy to Secure the Airway and Avoid Complications?

In evaluating the different options one has to consider the following key points:

• How much time is there to act?
• What equipment is available?
• Which technical skills are available?
• For the tube change, should spontaneous ventilation be maintained or ablated?

The first question has already been answered, as the patient is temporarily stable and should tolerate at least several minutes in the present situation. This will enable the necessary equipment to be obtained, as well as additional expertise. It may also allow the option of transferring the patient to the OR for the tube change, if great difficulty is anticipated.

In an ICU airway emergency, the needed equipment is rarely immediately available at the bedside. Contents and location of the airway equipment cart within the ICU should be well known. If the patient is stable and a difficult airway is anticipated, there may be time to obtain additional equipment from the OR.

Which procedure to choose will depend partially on the skills and experience of the attending practitioner. While there is much to be said for using familiar techniques and equipment, if time permits, additional expertise can be obtained to perform a less familiar technique (eg, tracheotomy), if indicated.

Preservation of spontaneous respiration during the tube change will provide the advantage of maintaining oxygenation for a short period of time should placement of the new ETT prove problematic after removal of the defective one. However, this patient is agitated, and will likely have to be deeply sedated for the procedure, putting him at risk of apnea. The downside of having an apneic patient would then occur without the upside of conditions optimized by a skeletal muscle relaxant. On the other hand, choosing to deliberately ablate spontaneous respirations with an induction dose of sedative/hypnotic and use of a skeletal muscle relaxant will provide for optimal conditions for the tube change but should occur only with an appreciation of (and preparations for) the difficulty that may be encountered during the procedure.

29.3.2. What Options Exist for Exchanging the ETT?

As pointed out earlier, obstruction of the upper airway imposes a significant risk for the placement of a new endotracheal tube. Whenever tracheal extubation is required prior to reintubation with a new ETT, there is a chance that the new tube might not pass into the trachea. This could be caused by displaced, collapsed, or edematous tissue, which was previously held open by the ETT.

For the tube exchange, a number of options exist. With appropriate preparation, the defective tube can either simply be removed and a new one placed, or the procedure can occur over an airway exchange catheter. For the former option, as discussed earlier in Section 29.2.2.2, it must be appreciated that intubation by DL will most likely not succeed. Other options such as the lightwand, intubating laryngeal mask airway, or video laryngoscope, such as the Glidescope, are more likely to succeed, but (a) the equipment must be available and (b) the practitioner must be experienced in its use. Use of an airway exchange catheter would be judged preferable by many practitioners in this context, as following removal of the defective tube, a fairly rigid conduit remains in the trachea to guide the new tube to the appropriate location. In contrast to the Eschmann tracheal introducer (gum elastic bougie), the exchanger catheter has a hollow lumen with a connector, so that oxygenation can be provided should passage of the new tube fail. This might happen if the tip of the endotracheal tube impinges on soft tissue of the laryngeal inlet during blind advancement. Other complications are esophageal displacement2 or pneumothorax, if used for jet ventilation.3 Use of airway exchange catheters has been discussed in detail in Chapter 28.

If an experienced surgeon is immediately available, a surgical airway (cricothyrotomy or tracheotomy) will result in an almost 100% success rate, although it is the most invasive option. The complication rate, including risk of significant bleeding, false cannula passage, pneumothorax, and infection, has been quoted to be as high as 12.5% in elective tracheotomy4 and even higher in emergencies. However, surgical airway in this setting would help avoid the risks inherent in a difficult tube change, and might be considered if time permits and there is a high probability that the patient will go on to tracheotomy anyway in the coming days or weeks. Otherwise, it will be a fallback option should other procedures fail for technical or time-critical reasons.

29.3.3. What Medications Can Be Used to Facilitate the Procedure?

The use of sedation in the ICU has decreased to much lower levels in recent years. Very few patients will tolerate a tube exchange without increasing their sedation, unless awake, cooperative, and topically well anesthetized. Compared to elective intubation in the operating room, the emergency intubation of critically ill patients carries a much higher risk of complications, for example, postintubation hemodynamic instability, which is associated with a significant mortality.5 Vasomotor insufficiency, impaired organ perfusion and microcirculation, an increased sympathetic tone, and lower oxygen delivery (a combination of anemia, hypoxemia, and low cardiac output) place these patients at high risk for profound hypotension, arrhythmia, and myocardial hypoperfusion, to name just the most vital consequences of short-term instability. Careful planning and the choice of drugs have a great impact on preventing hemodynamic instability. Although difficult to predict whether a patient will develop hemodynamic instability, it is important to have a plan in place to treat this early, before it becomes life threatening. Generally, it is not the particular combination of drugs, but the way they are administered that has the greatest effect on preserving hemodynamic stability.

The choice of drugs should reflect the level of sedation desired, anticipated effects on hemodynamics, and their interactions with patient physiology. The ideal drug has a short duration of drug effect, is metabolized independently from liver and kidney function, has minimal cardiodepressant or vasodilating effects, and can be easily titrated to the desired degree of sedation. Often, no single drug has all these attributes, so a combination of drugs may be necessary.

Propofol is a readily titratable agent, increasingly used for long-term sedation in the ICU. It has dose-dependent cardiodepressant and vasodilating effects.

Benzodiazepines have classically been used for sedation in the ICU but tend to have a very long half-life, a dependency on liver metabolism, and the risk of creating delirium. Short-acting benzodiazepines, such as midazolam, are preferred for procedural sedation.

Etomidate is an ultra short-acting sedative with little effect on hemodynamics. Unfortunately, even a single dose can induce adreno-cortical depression, although the clinical significance of this remains uncertain.

Ketamine has sedative and analgesic properties, while respiratory function and hemodynamic stability are preserved. In contrast to other hypnotic drugs, it causes a dissociative state in which patients tolerate uncomfortable or painful stimuli. Ketamine can cause hallucinations, which has led to substantially decreased use for many years. However, due to the increasingly recognized importance of hemodynamic stability, ketamine has experienced a revival in recent years.

Opioids are standard analgesics often used as adjuncts for procedures such as tracheal intubation. While cardioprotective (by preventing tachycardia), in the context of a critically ill patient they can cause hypotension by suppressing sympathetic drive.

Muscle relaxants may be used in conjunction with a sedative/hypnotic agent to optimize intubating conditions provided an airway assessment has been performed that suggests tracheal intubation will succeed, or fallback options such as ventilation using a bag-mask or EGD will be possible should intubation fail. With a hemiparesis of 72 hours' duration, succinylcholine should be avoided in this patient.

29.4.1. What Preparations Were Made for the Tube Exchange?

Tube exchange using an airway exchange catheter was the chosen technique, as the procedure is the least invasive combined with a good success rate. To help prevent soft tissue impingement during advancement of the new tube, a decision was made to do the exchange under indirect visualization of the glottis by videolaryngoscopy.6 A Glidescope® was obtained from the operating room for the purpose. The plan was determined as follows:

1. A second person skilled in airway management (ie, respiratory therapist, physician) was called to the bedside.

2. At least one more nurse was called to assist with calming the patient, administering drugs, charting, or calling for additional help if needed.

3. Tube feeds were confirmed off, and the stomach suctioned through the nasogastric tube. A rigid suction catheter connected to the wall suction was placed close to the patient's head.

4. The bed was moved away from the wall to increase working space. The patient was placed in 30 degrees of head elevation.

5. A call was made to the OR to ensure that a surgeon would be immediately available if needed.

6. The following airway management supplies were gathered at the bedside: An adult-sized, 19 Fr Cook Airway Exchange Catheter with Rapi-Fit ventilation adapter; a complete conventional intubation kit with laryngoscopes and Macintosh 3 and 4 blades (lights checked); a Glidescope®; ETTs sizes 7 to 9 mm ID; oropharyngeal and nasopharyngeal airways; Ambu® bag with oxygen reservoir and face masks of appropriate size; a # 4 and # 5 LMA-Classic and LMA-Fastrach (intubating LMA); Xylocaine spray and gel; an emergency cricothyrotomy kit. An 8.5 mm ID ETT was opened and the outside lubricated with Xylocaine gel.

7. The following drugs were prepared: propofol infusion, fentanyl, midazolam, and rocuronium. An additional vasopressor was not deemed necessary as a norepinephrine infusion of 0.05 μg.kg–1.min–1 was running to maintain an adequate mean arterial pressure.

8. It was confirmed that the patient's FiO2 had already been increased to 1.0. The patient was informed about the upcoming procedure.

29.4.2. Describe the Airway Exchange Procedure

After all equipment and additional staff were present at the bedside, the propofol infusion was increased to 2.5 mg.kg–1.h–1 and a bolus of 100 μg of fentanyl was given IV. The patient went to sleep, dropping his MAP by 12 mm Hg, but continued to breathe. The norepinephrine infusion was increased to 0.07 μg.kg–1.min–1.

After hemodynamic stabilization, the tube change procedure began. The patient's 8.5 mm ID ETT was loosened from the fixation and held in position by the respiratory therapist. The oropharynx was then suctioned to remove secretions. The patient was disconnected from the ventilator and manually ventilated with a manual resuscitator.

Standing behind the patient's head, the second practitioner introduced the Glidescope® into the oropharynx without resistance and the glottis was easily visualized on the screen. Importantly, no direct force or jaw thrust had to be applied, which enabled the patient to tolerate the procedure without the need to further deepen sedation. The glottis was sprayed with two sprays of 10% Xylocaine. Then, without interrupting ventilation, the airway exchange catheter was introduced into the trachea via a suction port adapter. The centimeter markings on the ETT and airway exchange catheter were lined up, then the exchange catheter was advanced a further 5 cm (Figure 29-2). Too deep an insertion should be avoided to prevent bronchial injury. The defective ETT was then withdrawn while holding the airway exchange catheter in place. The new 8.5 mm ID ETT was then advanced over the exchange catheter under videoscopic vision. With minor manipulations of the ETT, tube passage through the glottis without impingement on soft tissue was accomplished, thus minimizing patient's discomfort and coughing. One practitioner held the Glidescope® in place, while the other advanced the ETT over the exchange catheter. The ETT cuff was inflated, and the exchange catheter and Glidescope® removed. The manual resuscitator was connected and ventilation resumed. Correct ETT placement was confirmed by ETCO2 and auscultation. The procedural time without ventilation was less than 20 seconds, and the patient's SpO2 dropped from 91% to 88%. The patient was then reconnected to the ventilator, which caused the SpO2 to increase to 98%. Chest x-ray confirmed correct placement of the ETT tip 4 cm above the carina, and excluded pneumothorax or atelectasis.

An ETT cuff leak is not necessarily an indication for immediate tube exchange, since sufficient ventilation to prevent acute hypoxemia can be maintained in most situations. A careful plan is important to safely restore mechanical ventilation without causing additional harm to the patient.

In a difficult airway situation, such as fixation of the neck in a halo frame, an exit strategy, for example, emergency surgical airway, should be in place. Additional staff and all equipment needed should be at the bedside before starting the procedure.

The procedure can be completed with or without sedative/hypnotic and paralysis. If sedation alone is selected, it should be titrated to achieve just the level needed to tolerate the procedure. Oversedation is associated with the risk of hemodynamic instability and complications. Topical anesthesia of the vocal cords helps to prevent coughing and decreases the need for sedation.

Use of an airway exchange catheter is a safe procedure with low risk of complications. Its success rate can be increased by additional use of videolaryngoscopy. The ETT is exchanged over the exchange catheter under indirect vision, helping avoid impingement of the tube's tip on laryngeal structures. After the exchange, correct tube placement should be confirmed and intrathoracic complications excluded by chest x-ray.