Journal of Otology & RhinologyISSN: 2324-8785

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Case Report, J Otol Rhinol Vol: 3 Issue: 5

Management of Obstructive Sleep Apnea Following Endoscopic Skull Base Surgery

Kevin A Peng1*, Ashley E Kita1, Barbara M Van de Wiele2, Jeffrey D Suh1, Marvin Bergsneider3, and Marilene B Wang1
1Departments of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
2Departments of Anesthesiology, David Geffen School of Medicine at UCLA,Los Angeles, California, USA
3Departments of Neurosurgery, David Geffen School of Medicine at UCLA,Los Angeles, California, USA
*Corresponding author : Kevin A. Peng
10833 Le Conte Ave, CHS 62-132, Los Angeles, CA 90095, USA
Tel: 310-206-6766; FAX: 310-206-1393
E-mail: [email protected]
Received: July 16, 2012 Accepted: August 02, 2012 Published: August 05, 2012
Citation: Peng KA, Kita AE, de Wiele BMV, Suh JD, Bergsneider M, et al. (2014) Management of Obstructive Sleep Apnea Following Endoscopic Skull Base Surgery. J Otol Rhinol 3:5. doi:10.4172/2324-8785.1000187

Abstract

Management of Obstructive Sleep Apnea Following Endoscopic Skull Base Surgery

Objective: Obstructive sleep apnea (OSA) is associated with an increased risk for post-operative complications following general anesthesia. In this study, we examine our experience with OSA patients undergoing endoscopic skull base surgery and provide recommendations for management.

Methods: Medical records of patients undergoing endoscopic skull base surgery at a tertiary care center between 2009 and 2013 were reviewed.

Results: Forty-three patients were either previously diagnosed with or were suspected of having OSA. A nasopharyngeal airway was placed under direct endoscopic visualization prior to emergence in 42 patients (98%), and the airway was removed the first postoperative day. One patient experienced apnea and desaturation following transfer to the postanesthesia care unit, but was successfully re-intubated and re-extubated the same day.

Conclusion: The nasal airway of patients with OSA undergoing endoscopic skull base surgery may be compromised by the presence of edema, blood, and surgical packing. In addition, acromegaly and macroglossia in these patients further impacts pharyngeal patency negatively. A careful history and examination can identify patients at risk for OSA. The use of a nasopharyngeal airway in patients with OSA undergoing endoscopic skull base surgery is well-tolerated and safe, and may decrease the incidence of perioperative OSA-related complications.

Keywords: Obstructive sleep apnea; Skull base surgery; Management

Introduction

Obstructive sleep apnea (OSA) is the most common breathing disorder, with prevalence variably reported between 2 and 20% of all individuals [1-3]. It is characterized by partial or full collapse of the upper airway during sleep, resulting in episodes of breathing cessation lasting 10 seconds or greater. OSA has been associated with numerous medical morbidities, including hypertension, coronary artery disease, arrhythmias, and stroke, as well as a frank increase in mortality [4]. In the postoperative period, OSA is associated with complications such as hypoxemia, pulmonary edema, respiratory failure, reintubation, unplanned ICU admission, and longer postoperative hospitalization [5-7].
Risk factors for OSA include obesity, craniofacial abnormalities, alcohol use, and other diagnoses conferring either reduced airway size or a tendency for upper airway collapse [1,8,9]. Patients presenting with OSA commonly complain of daytime sleepiness, restless sleep, and snoring. The gold standard for diagnosis of OSA is polysomnography (PSG). More recently, due to availability and low expense, questionnaires and checklists have gained increasing use in the screening and diagnosis of OSA. Examples include the Berlin questionnaire, the American Society of Anesthesiologists (ASA) checklist, and the STOP-BANG questionnaire. Despite these diagnostic attempts, though, many individuals with OSA remain undiagnosed until evaluation for unrelated elective surgery.
Anesthesiologists have thus developed strategies to accommodate OSA patients during surgery as well as in the postoperative period. Such recommendations include: regional anesthesia where possible, advance preparation for a difficult airway, extubation only after full emergence and reversal of neuromuscular blockade, and avoidance of short-acting opioids or analgesics [2,8,9]. Systemic steroids may also be administered to help reduce soft tissue edema and subsequent respiratory events [10].
Postoperatively, continuous positive airway pressure may be applied to help prevent airway compromise and provide adequate oxygenation. Nasal packing, used in a variety of otolaryngologic procedures and surgeries to provide hemostasis as well as physical support, may become dislodged with positive pressure at the nasal cavities, thus increasing the risk of foreign body aspiration. Furthermore, nasal packing uniformly diminishes the patency of the nasal airway. Because of these considerations, it has been suggested that surgeons should consider packing around a nasopharyngeal airway [11].
Over the past two decades, endoscopic transnasaltranssphenoidal skull base surgery has emerged as the primary surgical intervention for pituitary adenomas and other anterior skull base lesions. The sequelae related to the sinonasal aspects of the procedure include nasal congestion, sinusitis, septal perforation, and epistaxis [12,13]. More immediately threatening, though, are the unique difficulties associated with airway management. It has been reported that patients with acromegaly are three times more likely to have difficult airway management during endoscopic skull base procedures than individuals with non-functioning tumors [13], a fact likely partially explained by the higher incidence of macroglossia among these patients. Furthermore, the use of continuous airway pressure may heighten the risk of tension pneumocephalus, a known complication of endoscopic skull base surgery [14,15]. In this context, a nasopharyngeal airway may provide a low-resistance channel through which respiratory support may be given.
The aim of the current study was to describe the protocol for immediate postoperative management of patients with OSA undergoing endoscopic skull base surgery at our institution.

Methods

All patients undergoing endoscopic skull base surgery performed between November 2009 and May 2013 were considered. Inclusion criteria included either a preoperative diagnosis of OSA or suspicion of OSA based on history, body habitus, and airway evaluation. Specifically, for patients with documented preoperative polysomnography, an apnea-hypopnea index (AHI) exceeding 5 was considered diagnostic for OSA. In addition, a suspicion of OSA was raised if any of the following criteria were met: subjective report of snoring, body mass index (BMI) exceeding 25.0, or Mallampati score of III or IV [16]. Forty-three patients met these inclusion criteria, and retrospective chart review was performed on this population.

Results

Patient characteristics of the cohort are shown in Table 1. Of the 43 patients, 32 were male (74%) and 11 were female (26%). Mean age was 50 years (range, 17 to 80 years). Mean body mass index (BMI) was 35.9 kg/m2 (range, 21.6 to 56.0 kg/m2). Of these individuals, two (5%) had BMI within normal (18.5 – 25 kg/m2), nine (21%) were overweight (BMI 25 – 30 kg/m2), and 32 (74%) were obese (BMI > 30 kg/m2). Mean surgical time was 3.2 hours (range, 1.8 to 8.9 hours). An ASA score of 3 was most commonly reported (29 patients, 67%), followed by ASA 2 (13 patients, 30%) and ASA 4 (1 patient, 2%). Mean duration of postoperative hospitalization was 3.3 days (range, 1 to 25 days).
Table 1: Patient characteristics.
Pathological diagnoses included pituitary adenoma alone (30 patients, 70%), Rathke’s cleft cyst alone (6 patients, 14%), concurrent pituitary adenoma and Rathke’s cleft cyst (2 patients, 5%), and craniopharyngioma, fibrous dysplasia of the clivus, cavernous sinus hemangioma, melanoma, and hypothalamic ganglioglioma (1 patient each, 2%). Seven patients (16%) presented preoperatively with acromegaly secondary to a growth-hormone (GH) secreting tumor.
In all patients but one (98%), a nasopharyngeal airway was placed intraoperatively, immediately prior to placement of nasal packing. In all but two of these patients, the nasopharyngeal airway was removed on postoperative day (POD) 1; one patient’s nasopharyngeal airway was removed on POD 0 secondary to significant patient discomfort immediately after emergence. Finally, one patient experienced apnea and desaturation following transfer to the postanesthesia care unit. Emergent re-intubation was successful, and the patient was maintained on positive pressure ventilation for approximately four hours prior to re-extubation. Her hospital course was otherwise uneventful.

Discussion

OSA is a prevalent public health concern. In addition to significant long-term medical morbidity, OSA confers immediate morbidity in the postoperative period. The mainstay of treatment for uncomplicated OSA is continuous positive airway pressure (CPAP), which has gained widespread acceptance since its advent in 1981 [17]. While CPAP is appropriate for outpatient nocturnal therapy, its role is limited in the postoperative period.
OSA has repeatedly been demonstrated to confer increased anesthetic risks, including postoperative hypoxemia, respiratory failure, atrial fibrillation, delirium, and admission to the intensive care unit [7]. Estimates of the incidence of these postoperative complications in the OSA population range from 14 to 44% [7,18,19]. Patients with OSA undergoing endoscopic skull base surgery present unique challenges. An increased incidence of acromegaly and macroglossia is seen in patients with GH-secreting pituitary adenomas. Furthermore, positive pressure applied to the oral and nasal cavities may lead to air trapping within the surgical bed, potentially leading to life-threatening pneumocephalus. Finally, nasal packing, used for hemostasis as well as buttressing local flaps obliterating the surgical bed, further compromises the nasal airway.
The anesthesia literature has suggested the use of a nasopharyngeal airway to improve upper airway patency in patients with OSA. Risks of nasopharyngeal airway placement are low, and are primarily related to the relatively infrequent occurrence of intracranial placement [20-22]. Intraoperative placement of a nasopharyngeal airway under continuous endoscopic visualization (Figure 1) greatly reduces the risk of unintentional intracranial placement, and provides a conduit for air passage even with the use of nasal packing. By increasing the patency of the upper airway, potential perioperative complications related to sleep apnea, including hypoxemia, pulmonary edema, respiratory failure, and reintubation may be minimized.
Figure 1: Intraoperative placement of a nasopharyngeal airway following resection of pituitary adenoma. S = septum, NA = nasopharyngeal airway, IT = inferior turbinate.
In our series, 42 of 43 patients diagnosed with OSA or suspected of having OSA based on symptomatology or airway examination underwent intraoperative placement of a nasopharyngeal airway following endoscopic skull base surgery. Only one patient experienced a complication attributable to OSA in the perioperative period—specifically, apnea in the postanesthesia care unit requiring intubation. Patient-specific factors likely contributing to the need for reintubation in this patient included avoidance of acetaminophen resulting in a likely higher dose of narcotic than otherwise would have been administered, transport of the patient in a supine position, and a history of pulmonary fibrosis and intrinsic lung disease secondary to an underlying autoimmune disorder. Still, our incidence of complications 2% remains favorable compared to the literature.
Based on our experience with this population, our protocol for management has evolved to encompass the following: preoperatively, we aggressively pursue diagnosis of obstructive sleep apnea via a sleep study, with documentation of quantitative parameters (apneahypopnea index [AHI] and minimum oxygen saturation in the absence of CPAP). Formal briefing and debriefing are performed with the anesthesia providers and the surgical team before and at the end of the case, respectively. All patients with demonstrated OSA undergo intraoperative placement of a nasopharyngeal airway, under direct endoscopic visualization, prior to placement of nasal packing. Acetaminophen is administered toward the end of surgery to reduce the need for narcotics.
Higher-risk patients, defined as an AHI > 40 and/or a minimum oxygen of saturation of 70%, are more closely monitored in the postanesthesia care unit (PACU) and are transferred to the intensive care unit (ICU) for the first postoperative night. Patients with mild or moderate OSA are monitored for at least two hours in the PACU prior to transfer to the floor. Use of the nasopharyngeal airway is continued until the first postoperative day, with a laminated sign displayed prominently at the patient’s bedside dictating that the nasal trumpet not be removed or replaced.
In summary, strict preoperative stratification of patients for OSA maximizes patient safety in a resource-effective manner. Recognition of at-risk patients is of paramount importance, and once the diagnosis of OSA is made, intraoperative placement of a nasopharyngeal airway allows for a low-resistance conduit for postoperative respiration. Monitoring following general anesthesia is stratified by patient risk, and the nasopharyngeal airway is removed on the first postoperative day. By adhering to this protocol, we have experienced few OSArelated perioperative complications, and advocate implementation of this protocol for patients undergoing endoscopic skull base surgery.

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