Endoscopic sinus approach has become one of the most common surgical techniques for endoscopic sinus and skull base surgery. Anesthetic management has an important impact on the overall patient management, from the preoperative assessment and management to the quality of the surgical field and the postoperative recovery. Hemostasis is critical for adequate anatomical endoscopic visualization. Mild controlled hypotension seems to improve the visibility of the surgical field. Reduction of intraoperative bleeding should be considered during the treatment planning. Preoperative preparations include the optimization of comorbidities and cessation of drugs that may inhibit coagulation.
Key learning points
At the end of this article, the reader will:
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Understand specific areas of concern involved in preoperative evaluation for these surgeries.
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Become familiar the anesthetic goals for endoscopic sinus and skull base surgery.
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Understand the steps that can be performed preoperatively to prepare the patient for the surgery and to facilitate anesthesia and recovery.
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Recognize important considerations during and immediately after induction of anesthesia.
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Be able to discuss the effects of maintenance anesthesia techniques on blood loss and surgical field.
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Become familiar with some specific challenges during emergence of anesthesia for these surgeries.
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Describe some postoperative problems that can affect recovery after surgery and how to best treat them.
Introduction
Role of the Anesthesiologist in Endoscopic Sinus and Skull Base Surgery
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Preoperative assessment
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Perioperative management
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Anesthetic management
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Quality of the surgical field
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Postoperative recovery
Endoscopic approach to the sinuses has become one of the most common surgical techniques not just for sinus surgery but also for skull base surgery ( Table 1 ). The anesthesiologist has a vital role in the overall management of the patient, from the preoperative assessment and management to the quality of the surgical field and the postoperative recovery. Most of the principles of anesthetic care discussed in this review come from studies done in endoscopic sinus surgery. Mild controlled hypotension, with remifentanil and either propofol or an inhaled anesthetic, can improve the visibility of the surgical field. However, if there is concern regarding intracranial pressure and cerebral perfusion, it would be more appropriate to manage the patient following the basic principles of neuroanesthesia. Some patients may be at increased risk for postoperative respiratory depression, given comorbidities such as obstructive sleep apnea (OSA), obesity, acromegaly, and nasal packing. Pain and control of postoperative nausea and vomiting (PONV) are crucial, and their management starts in the preoperative period.
| Sinonasal surgery | Sinusitis, nasal polyposis, epistaxis, sinus mucoceles, tumors, turbinate reduction, septoplasty |
| Skull base surgery | CSF leak closure, pituitary surgery, encephaloceles/meningoceles, tumors |
| Orbital surgery | Orbital decompression, dacryocystorhinostomy, optic nerve decompression |
Introduction
Role of the Anesthesiologist in Endoscopic Sinus and Skull Base Surgery
- •
Preoperative assessment
- •
Perioperative management
- •
Anesthetic management
- •
Quality of the surgical field
- •
Postoperative recovery
Endoscopic approach to the sinuses has become one of the most common surgical techniques not just for sinus surgery but also for skull base surgery ( Table 1 ). The anesthesiologist has a vital role in the overall management of the patient, from the preoperative assessment and management to the quality of the surgical field and the postoperative recovery. Most of the principles of anesthetic care discussed in this review come from studies done in endoscopic sinus surgery. Mild controlled hypotension, with remifentanil and either propofol or an inhaled anesthetic, can improve the visibility of the surgical field. However, if there is concern regarding intracranial pressure and cerebral perfusion, it would be more appropriate to manage the patient following the basic principles of neuroanesthesia. Some patients may be at increased risk for postoperative respiratory depression, given comorbidities such as obstructive sleep apnea (OSA), obesity, acromegaly, and nasal packing. Pain and control of postoperative nausea and vomiting (PONV) are crucial, and their management starts in the preoperative period.
| Sinonasal surgery | Sinusitis, nasal polyposis, epistaxis, sinus mucoceles, tumors, turbinate reduction, septoplasty |
| Skull base surgery | CSF leak closure, pituitary surgery, encephaloceles/meningoceles, tumors |
| Orbital surgery | Orbital decompression, dacryocystorhinostomy, optic nerve decompression |
Preoperative evaluation of pituitary and skull base surgical patients
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Coexisting medical manifestations of operative disease
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Staged surgery
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Risk of excessive intraoperative blood loss and transfusion
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Risk of prolonged intubation
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Risk of perioperative respiratory depression
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Cardiovascular status
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Evaluate neurologic deficits and endocrine function
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Adenomas secreting adrenocorticotrophic hormone (ACTH): obesity, hypertension, osteopenia, fluid retention, and hyperglycemia
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Growth hormone (GH) secreting adenomas: careful evaluation of the airway
Endoscopic skull base surgery
Patients undergoing endoscopic pituitary resection can present with manifestations of the disease for which they are having surgery. It is necessary to assess and document any neurologic deficits and to evaluate the endocrine function. Perioperative testing should include measurement of glucose and electrolytes. Prolactin-secreting adenomas are the most common lesions, but for the anesthesiologist, ACTH and GH are cause for greater concern.
GH excess causes acromegaly. Careful evaluation of the airway is important for these patients. They can have an enlarged tongue causing difficult intubation, and cartilaginous hypertrophy of the arytenoids and narrowing of the tracheal rings require the use of small size endotracheal tubes (ETTs). ACTH excess causes Cushing disease, leading to obesity, hypertension, osteopenia, fluid retention, and hyperglycemia. Patients with pituitary hypofunction are usually receiving hormone replacement therapy that must be continued perioperatively.
For patients with vascular tumors, preoperative embolization of the tumor reduces bleeding and the need for transfusion as well as improves the visualization of intraoperative surgical field.
Local versus general anesthesia in sinus and skull base surgery
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Patient able to signal pain should minimize surgical complications
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Less blood loss with better surgical field has been described for local anesthesia
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Better recovery profile with fewer incidences of nausea and faster discharge
Advantages of general anesthesia
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Less anxiety and discomfort
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Total immobility should provide a better surgical field and minimize surgical complications
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Improved control of airway with increased safety for the patient
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Decreased fire risk
When endoscopic sinus surgery was introduced, patients were often operated totally under local anesthesia with combined sedation. However, surgical techniques have evolved, and many of the currently performed surgical procedures require general anesthesia. Surgery under local anesthesia alone is still considered appropriate for minor sinus procedures in selected patients. However, presently, local anesthesia is used to complement general anesthesia.
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Provide a still and bloodless surgical field to minimize surgical complications
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Prevent cerebral ischemia
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Protect the patient’s airway during and after surgery from contamination by blood and gastric fluid and from respiratory depression and obstruction
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Facilitate early recovery, by optimizing pain and nausea control
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Acromegaly
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Moderate to severe OSA
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STOPBANG 5 or greater
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Body mass index (BMI) of 45 or greater
STOPBANG is an acronym for a series of questions that can be asked to patients to screen for OSA, which increases a patient’s risk for postoperative respiratory depression. STOPBANG stands for: S noring? T ired? O bserved (observed apnea during sleep)? P ressure (high blood pressure)? B MI (>35 kg/m 2 ), A ge (>50 years old), N eck circumference (>16 inches), G ender (male). If the patient answers “yes” to 5 to 8 of the questions, there is a high risk of having OSA.
There is an increased risk of respiratory complications during the perioperative period for patients undergoing endoscopic surgery. Patients should be routinely screened for OSA and obesity. The severity of previously diagnosed OSA should be documented as well as the home use of continuous positive airway pressure (CPAP) devices. Patients without a formal diagnosis of OSA should be screened with instruments such as the STOPBANG scale, and scores of 5 or more should be noted, because they correlate with a likelihood of moderate to severe OSA. Patient’s height and weight should be documented and their BMI calculated, because obese patients are at higher risk for respiratory depression ( Table 2 ).
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Formulate a perioperative plan for antiplatelet and anticoagulant therapy, in consultation with cardiologist and primary care physician
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Evaluate patient’s ability to tolerate local vasoconstrictors
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Evaluate patient’s ability to tolerate hypotension
| Preoperative | Use nonopioid analgesics: acetaminophen, COX-2 inhibitors |
| Induction of anesthesia | Careful positioning and prolonged preoxygenation of obese patients; use muscle relaxants to facilitate intubation; availability of additional tools for intubation such as videoscopes; consider use of ETT over LMA |
| Maintenance of anesthesia | Consider use of desflurane, remifentanil, dexmedetomidine; try to avoid long-acting medications such as isoflurane, morphine, hydromorphone |
| Emergence of anesthesia | Verify complete reversal of muscle relaxation; consider awake extubation |
Patients should be evaluated for a history of coronary artery disease (CAD) and arrhythmias. Cessation of anticoagulants and antiplatelet agents is ideal, but at the same time, the risks of stopping these medications must be considered. If the patient has CAD, has a history of cardiac stents, or is chronically on anticoagulants, care should be coordinated with the cardiologist and the primary care physician in order to prevent perioperative cardiac ischemia, pulmonary embolism, or ischemic strokes.
The ability to tolerate locally applied vasoconstrictors should be evaluated, because there is a risk of these medications producing cardiac arrhythmias or cardiac ischemia. However, if used appropriately, the risk is significantly reduced (see Pant H: Hemostasis in Endoscopic Sinus Surgery , in this issue). Relative hypotension with controlled heart rate provides a better surgical field for endoscopic surgery. A cardiovascular evaluation should also take into consideration the ability of the patient to tolerate mild hypotension. Acromegaly is associated with increased risk of cardiovascular disease ranging from cardiomyopathy to CAD and arrhythmias; proper evaluation of these potential complications should be made preoperatively.
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Glucocorticosteroids (steroids)
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Antibiotics
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Topical vasoconstrictors and local anesthesia
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Pain medications: acetaminophen and cyclooxygenase-2 (COX-2) selective inhibitors
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Inhaled bronchodilators if indicated
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Invasive monitoring, such as arterial line, if required
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For cerebrospinal fluid (CSF) leak repair: intrathecal fluorescein injection; consider lumbar drain
Many patients undergoing endoscopic sinus and skull base surgery may be on steroids chronically. These patients do not routinely need a stress dose of steroids as long as they receive their usual daily maintenance steroid dose, orally preoperatively or the equivalent intravenous dose intraoperatively.
A short course of antibiotics is used preoperatively in some patients where indicated, to decrease inflammation and risk of infection. However, there is no good evidence for their routine use in prevention of infections or improving the surgical field. Most surgeons request one dose of intravenous antibiotics for infection prophylaxis before surgical incision.
Many patients undergoing sinus surgery have concomitant asthma; preoperative use of inhaled bronchodilators is indicated in these patients. Concerns exist about the probability of life-threatening bronchospasm with the triad of nonsteroidal anti-inflammatory drugs (NSAIDs), asthma, and nasal polyps.
Local vasoconstrictors and local anesthesia are typically applied topically and via mucosal injections to improve the surgical field by providing mucosal decongestion, and perioperative pain management. Longer-acting local anesthetics such as ropivacaine should be considered for their longer lasting benefit.
Pain management can start in the preoperative period. Acetaminophen and COX-2 inhibitors can improve pain management and reduce narcotic requirements.
In patients undergoing skull base surgery, depending on the approach and the operative lesion, the anesthesiologist should be prepared to resuscitate the patient in the rare event of a vascular injury. The anesthesiologist may choose to have blood products readily available and to place additional monitors, such as an arterial line, depending on the patient and the surgical plan.
In some patients undergoing repair of a CSF leak, fluorescein administration through a lumbar spinal puncture may be needed. Anesthesiologists usually assist the surgeon by performing the procedure in the preoperative area under sterile technique. The fluorescein helps localize the site of the CSF leak during surgery. The surgeon may also request a lumbar drain to be placed to drain CSF in cases where increases in intracerebral pressure (ICP) are expected.
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Anxiolytics: midazolam, lorazepam
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Analgesics: fentanyl, remifentanil
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Hypnotics: inhaled anesthetics, propofol, etomidate
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Muscle relaxants: succinylcholine, nondepolarizing muscle relaxants (NMBDs)
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Other medications
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Dexamethasone
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Tranexemic acid
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