What the Anesthesiologist Should Know before the Operative Procedure
The functional impairment of air movement will be proportional to the amount of tracheal stenosis, which will determine preoperative care, time for preoperative work-up, and timing of surgery. The normal adult trachea is about 2 cm in diameter, and flow will be reduced to one-third normal when the diameter falls below 6 mm. The most common cause of tracheal stenosis is fibrosis/injury from a prior intubation, but cancer and inflammatory diseases, like sarcoid, amyloid, and Wegener’s granulomatosis, are also seen.
1. What is the urgency of the surgery?
What is the risk of delay in order to obtain additional preoperative information?
The risk of delay depends on the amount of airflow impairment. At a minimum, these patients will need to have a CT 3-D reconstruction of the trachea and bronchoscopy to define the length and degree of impairment and determine if the stenosis is from trauma, cancer, etc. While there is risk of profound intraoperative hypoxemia and hypercarbia, there is minimal blood loss or fluid shifts, so preoperative work-up can be focused (see below), with attention paid to right heart function and pulmonary hypertension.
Tracheal stenosis is typically considered an urgent surgery, as the patients will not undergo surgery until they are symptomatic.
Emergent: Tracheal surgery becomes emergent in an adult when the minimal airway diameter falls to the point where oxygenation and ventilation are impaired. These patients may be admitted for helium/oxygen therapy or may need a tracheostomy, if their anatomy allows.
Urgent: Most tracheal resections are considered urgent, since the patients are symptomatic from impaired air movement. However, they are typically scheduled a week or more in advance, so a few days’ delay (such as for the patient to get over a cold) is appropriate.
Elective: These patients have stable and nonprogressing lesions. They may be symptomatic only with exertion.
2. Preoperative evaluation
Medically unstable conditions warranting further evaluation include unstable angina, new/worsening CHF, TIA/stroke, uncontrolled diabetes, uncontrolled hypertension, and current airway or pulmonary infection.
Delaying surgery may be indicated if there is any acute exacerbation of baseline disease that is amenable to amelioration. The disease process should make intraoperative or postoperative care more risky if significant delay is sought.
3. What are the implications of co-existing disease on perioperative care?
Preoperative evaluation is based on patient presentation. Unique to tracheal stenosis is that the majority of adults seek resection due to an injury from a prior intubation. The reason for the operation and injury (difficult intubation, stylette injury, prolonged intubation, high ETT cuff pressures, etc.) needs to be clarified. Patients presenting with stenosis from inflammatory disease (amyloid, Wegener’s granulomatosis, and sarcoid) need to have their disease status clarified.
Perioperative risk reduction strategies
Improvement of airflow is critical for risk reduction. Often a stenotic lesion can be dilated for a temporary improvement in preoperative airflow in the days before surgery. This dramatically improves a patient’s ability to perform pulmonary toilet and allows normalization of carbon dioxide and eliminates hypoxemia. Other pulmonary therapy is elimination of any other bronchoconstriction and pulmonary infection through aggressive preoperative pulmonary rehabilitation (there are no strong data to support pulmonary rehabilitation, but most comes from lung volume reduction). Helium/oxygen gas mixture can be employed for patients with critical stenoses where preoperative dilatation is not possible. This lower density gas will help improve ventilation and oxygenation.
b. Cardiovascular system
Unstable angina: needs to be addressed as a medical emergency. Cardiology consult will determine if medical versus interventional therapy is necessary. The cardiologist should also be consulted for management of platelet inhibitors or other anticoagulants.
New/worsening CHF: Valvular function needs to be ascertained to determine need for repair or uncover an ischemic cause for dysfunction. Ventricular function can be examined at the same time. Inotropic support and volume status can then be adjusted as necessary.
Baseline coronary artery disease or cardiac dysfunction – Goals of management
AHA/ACC guidelines should be followed. Stable conditions typically do not interfere with surgery.
Amyloid effects on the heart need to be followed
Any pulmonary hypertension and/or right heart failure needs to be ruled out (or minimized if present) due to obligate intraoperative hypercarbia.
Many patients with tracheal stenosis will have smoking-related disease. Tracheal stenosis can interfere with pulmonary toilet, so patients are at greater risk for retained secretions and pneumonia. Reduced airflow can make a multidose inhaler far less effective and the patient may need nebulized delivery of bronchoactive medications.
Reactive airway disease (Asthma)
Reduced airflow can make a multidose inhaler far less effective and the patient may need nebulized delivery of bronchoactive medications.
Arterial carbon dioxide: Severe airflow constriction can lead to such a reduction in minute ventilation that CO2 can accumulate. This can be tracked as a marker of severity of compromise. Preoperative airway dilatation can help to temporarily relieve the obstruction to allow normalization.
Sarcoid’s effect on the lung needs to be followed and treated
There are no specific renal and gastrointestinal issues unless the tracheal injury was from an intubation due to renal and GI disease. Patient’s with Wegener’s are at risk of severe renal disease.
Potential complications of Wegener’s and sarcoid need to be followed.
Chronic disease: Pulmonary hypertension and right heart failure are potential profound contraindications to surgery due to the obligate intraoperative hypercarbia.
Steroid therapy for Wegener’s, sarcoid, and amyloid needs to be continued into the perioperative period. It is unclear if “stress dose” steroids are needed compared to the usual daily dose of steroids. Regardless, steroid supplementation needs to be continued.
g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
4. What are the patient's medications and how should they be managed in the perioperative period?
h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
i. What should be recommended with regard to continuation of medications taken chronically?
Cardiac: Continue all blood pressure medications and antiarrhythmics.
Pulmonary: Continue all medications. Consider nebulized medications rather than MDI.
Antiplatelet: Aspirin can be continued. IIb/IIIa inhibitors (Plavix) will probably need to be discontinued 1 week in advance, but this issue should be discussed with the cardiologist, especially if the patient has a drug eluting stent.
Steroids should be continued.
Diabetic medications are handled in the usual manner.
j. How To modify care for patients with known allergies –
Patients with specific allergies can be handled in the usual fashion.
k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
Latex allergy poses no additional issues (above normal) assuming a latex-free operating room/airway equipment.
l. Does the patient have any antibiotic allergies- – Common antibiotic allergies and alternative antibiotics]
First-generation cephalosporins are typically used. Clindamycin and vancomycin can be substituted. Ampicillin-sulbactam can also be used.
m. Does the patient have a history of allergy to anesthesia?
A total intravenous anesthetic, typically with propofol and remifentanil, is a necessary part of intraoperative management and can be used for the entire procedure.
Local anesthetics/muscle relaxants
Neither local anesthetics nor muscle relaxants are a necessary part of the anesthetic. Avoidance of muscle relaxants may necessitate a more profound depth of general anesthesia to ensure immobility. This increase in depth typically causes more hypotension and a vasopressor (typically phenylephrine) infusion is added.
5. What laboratory tests should be obtained and has everything been reviewed?
Patients for tracheal resection will have had serial PFTs and chest CT scans. Other laboratory tests are based on concomitant disease, comorbidities, and age.
Common laboratory normal values will be same for all procedures, with a difference by age and gender.
Hemoglobin levels: Anemia can be seen as part of Wegener’s granulomatosis, sarcoid, and amyloid. Patients can have anemia from multiple blood draws with prolonged hospitalizations. Smokers may have polycythemia.
Imaging: All patients will have chest/airway CT with 3-D reconstruction. Imaging/testing for cardiac ischemia is based on AHA/ACC guidelines. Wegener’s patients require renal imaging for routine follow-up, but not specifically for tracheal surgery. Patients with amyloid should have an echocardiogram. Pulmonary hypertension and right heart failure need to be measured/ruled out.
Other tests: Arterial blood gas may be indicated if there are signs of CO2 retention.
Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
Tracheal resection is managed with general anesthesia. An in-depth airway management plan needs to be formally discussed with the surgeon as the airway will be shared for much of the procedure. Total intravenous anesthesia (TIVA) will be needed at least intermittently, and it may be easier to use it for the entire operation. An arterial line is placed for blood gas analysis.
The degree and position of the stenosis will determine initial airway management. A proximal and narrow stenosis that is too tight to be bridged by a 4.0-mm endotracheal tube (~6-mm stenosis) can potentially be managed by using an LMA. Another option is use of jet ventilation by placing a catheter through the stenosis. A transtracheal catheter can be placed for jet ventilation. Finally, an awake tracheostomy in the area of the distal tracheal incision can be made. With a distal stenosis, the ETT can be placed proximal to the stenosis.
Regardless of the approach, careful attention needs to made to prevent barotrauma due to obstruction of exhalation. Rising CO2 is expected and tolerated quite well by most patients.
Once the initial airway management has been accomplished, the surgeon will dissect down to the trachea. The surgeon will make a distal tracheal incision. At this point, a sterile ETT can be inserted into the distal trachea and sterile ventilator tubing handed across the field. Normal tidal ventilation is maintained until the surgeon completes the posterior tracheal anastomosis. The distal ETT is removed and a jet ventilation catheter is passed through an ETT placed through the vocal cords. The jet catheter is positioned by the surgeon distal to the anastomosis.
Once the tracheal anastomosis is complete, the ETT can be positioned with a bronchoscope either proximal or distal to the anastomosis. The cuff should not be inflated across the anastomosis. If the ETT is proximal to the anastomosis, the peak inspiratory pressures should be minimized to minimize the impact on capillary blood flow.
There is no typical role for regional anesthesia. Theoretically, airway surgery can be accomplished with an awake patient and bilateral cervical plexus blocks.
Benefits: This is the only way to accomplish the surgery.
Drawbacks: Inhalational anesthesia cannot be used throughout the case due to long periods of an open trachea.
Other issues: TIVA is optimal.
6. What is the author's preferred method of anesthesia technique and why?
What do I need to know about the surgical technique to optimize my anesthetic care?
A detailed discussion of airway management needs to occur preoperatively (see section on Intraoperative Management)
What can I do intraoperatively to assist the surgeon and optimize patient care?
The patient needs to be positioned supine with a shoulder roll to extend the neck. The arms are tucked and padded.
What are the most common intraoperative complications and how can they be avoided/treated?
Prioritize them by urgency. Hypoxemia and hypercarbia are very common. Hypercarbia is essentially unavoidable.
Cardiac: Hypoxemia can lead to myocardia ischemia. Hypercarbia can lead to right heart strain/failure due to pulmonary hypertension.
Pulmonary: Debris in the airway can move distally and block segments or bronchi. A bronchoscopic examination of the airway prior to extubation is required.
b. If the patient is intubated, are there any special criteria for extubation?
At the end of the procedure, the patient should not extend the head as this puts tension on the tracheal anastomosis. The surgeon will often place a suture from the base of the chin into the anterior neck to prevent the patient from extending the neck. The patient’s head should be propped forward with a pillow.
c. Postoperative management
Patients are typically managed with intravenous opioids and nonsteroidal anti-inflammatory drugs or acetaminophen. Respiratory rate monitoring and pulse oximetry are paramount. New transcutaneous CO2 monitors may offer a real benefit in terms of highlighting when a patient is hypoventilating, but they have not entered wide service.
The patient should ideally be cared for by nurses who are specifically trained in caring for post-thoracic surgery patients. These patients need a specific focus on pulmonary toilet and airway integrity.
These patients are at risk for vocal cord malfunction, airway swelling, and hypoventilation. Usually the postoperative swelling is far less than the initial stenosis. Dehiscence of the anastomosis is possible if the patient is hypotensive or has prolonged postoperative positive pressure ventilation.
What's the Evidence?
Gaissert, HA, Burns, J. “The compromised airway: tumors, strictures, and tracheomalacia”. Surg Clin North Am. vol. 90. 2010. pp. 1065-89.
Daumerie, G, Su, S, Ochroch, EA. “Anesthesia for the patient with tracheal stenosis”. Anesthesiol Clin. vol. 28. 2010. pp. 157-74.
Wain, JC. “Postintubation tracheal stenosis”. Semin Thorac Cardiovasc Surg. vol. 21. 2009. pp. 284-9.
Pinsonneault, C, Fortier, J, Donati, F. “Tracheal resection and reconstruction”. Can J Anaesth. vol. 46. 1999. pp. 439-55.
Remy, J, Remy-Jardin, M, Artaud, D, Fribourg, M. “Multiplanar and three-dimensional reconstruction techniques in CT: impact on chest diseases”. Eur Radiol. vol. 8. 1998. pp. 335-51.
Brandom, BW. “Postoperative management of laryngotracheal reconstruction”. Int Anesthesiol Clin. vol. 35. 1997. pp. 127-44.
Wanamaker, JR, Eliachar, I. “An overview of treatment options for lower airway obstruction”. Otolaryngol Clin North Am. vol. 2. 1995. pp. 751-70.
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- What the Anesthesiologist Should Know before the Operative Procedure
- 1. What is the urgency of the surgery?
- What is the risk of delay in order to obtain additional preoperative information?
- 2. Preoperative evaluation
- 3. What are the implications of co-existing disease on perioperative care?
- b. Cardiovascular system
- c. Pulmonary
- d. Renal-GI:
- e. Neurologic:
- f. Endocrine:
- 4. What are the patient's medications and how should they be managed in the perioperative period?
- i. What should be recommended with regard to continuation of medications taken chronically?
- j. How To modify care for patients with known allergies -
- l. Does the patient have any antibiotic allergies- - Common antibiotic allergies and alternative antibiotics]
- m. Does the patient have a history of allergy to anesthesia?
- 5. What laboratory tests should be obtained and has everything been reviewed?
- 6. What is the author's preferred method of anesthesia technique and why?
- a. Neurologic:
- b. If the patient is intubated, are there any special criteria for extubation?
- c. Postoperative management