Chapter 57 The postoperative management of OSA patients after uvulopalatopharyngoplasty. Inpatient or outpatient?
Obstructive sleep apnea (OSA) is a condition that is estimated to affect up to 4% of the adult population.1 The OSA syndrome can be defined as the periodic cessation of airflow during sleep. The most common symptoms of this syndrome include loud snoring, daytime sleepiness and cognitive impairment. A variety of surgical procedures, which include tracheotomy, nasal surgery, and uvulopalato-pharyngoplasty (UPPP) with or without tonsillectomy, may be performed to alleviate symptoms and improve the patient’s quality of life.
Out of the available procedures, UPPP is the most common surgery performed for adult patients with OSA. It was originally introduced by Fujita in 1981.2 Despite the frequency of this procedure, the appropriate level of postoperative monitoring for complications has become a controversial issue. Initially all UPPP patients were monitored postoperatively in the intensive care unit. It is the opinion of the authors of this chapter that there is no unique danger to uvulopalatopharyngoplasty for obstructive sleep apnea that would require such intensive postoperative observation. Nonetheless, otolaryngology textbooks typically recommend close observation in the recovery area and subsequent transfer to the intensive care unit for the first 24 hours post UPPP.3 Currently, some surgeons still advocate a 24-hour observation period as a routine part of postoperative management.
On the other hand, others may prefer close monitoring but do not recommend it as a routine practice. Instead they base the need for extended observation on the severity of a patient’s OSA, the extent of the operation and the presence of pre-existing medical conditions. In fact, many recent reports have concluded that routine postoperative ICU monitoring is not necessary, stating that intensive care or step-down unit monitoring should not be required for most patients after upper airway surgery for OSA since most complications occur within a few hours of the procedure.4–6
While it is clear that a variety of factors may influence a surgeon’s decision to prolong postoperative care, studies have shown that most overnight admissions for UPPP are uneventful and in most cases, same-day discharge is advisable.7 Based on this fact, this chapter seeks to clarify and outline appropriate postoperative management strategies of OSA patients undergoing UPPP.
Inherently, there is no greater risk of postoperative complications with UPPP surgery than with tonsillectomy, which is commonly conducted on an outpatient basis. While complications do occur after UPPP, researchers have shown that they are most common in the immediate, postoperative care period and overnight stay may not be a necessary part of postoperative management of OSA patients undergoing UPPP.8
Although the overall incidence of serious postoperative complications after UPPP is low,9 it is important to review which complications may occur in order to understand how they affect a surgeon’s approach to managing patients. In the case of UPPP, complications may be categorized as either early or late events. Early complications can be defined as those that occur either intraoperatively, immediately postoperatively or in the recovery room. Late complications may be observed over the course of the inpatient stay. The most commonly reported early postoperative complications are either respiratory in origin or involve bleeding from the surgical site.8 Other early complications include arrhythmia, hypertension, pain, dehydration and poor oral intake. All of these possibilities should be addressed before determining the most appropriate postoperative management plan for UPPP patients.
The most common serious respiratory complications after UPPP are airway obstruction and oxygen desaturation. Complete and untreated airway obstruction may lead to respiratory arrest, and reintubation or emergency tracheo-tomy could become necessary and lifesaving.
Although airway obstruction may be considered a common postoperative complication after UPPP, the actual incidence of such an event is quite low. Additionally, there has been a change in the number of serious respiratory complications reported over time, with more recent studies reporting lower rates. For example, in 1989 Esclamado et al.10conducted a retrospective chart review of 135 patients surgically treated for OSA and found the incidence of respiratory complications to be 10.3%. Half of these complications were airway obstructions that occurred at extubation, and half were due to failed intubation. It is important in a discussion of postoperative management to note that the onset of all respiratory events occurred in the early phase. That is, all respiratory complications occurred during or immediately after intubation. A review in 1994 by Haavisto and Suonpaa11 of 101 patients undergoing UPPP for OSA showed an incidence of airway complications of 11%. Again all cases occurred in the early phase.
In a 1998 review of 109 patients undergoing UPPP for OSA, Terris et al. reported a 5.5% incidence or early respiratory complications.6 This rate included one case of airway compromise, and the patient required naloxone, oxygen and suctioning of his airway. This single episode of airway obstruction occurred only 15 minutes after the patient was transferred out of the operating room.
An additional 1998 study by Mickelson and Hakim of 347 patients undergoing UPPP for OSA reported only five patients who had experienced airway-related complications, or 1.4% of all patients.5 Three of the five suffered shortness of breath either at extubation or immediately after in the recovery room. Two of the five patients experienced complications in the surgical ward. These included one case of pulmonary edema and one case of shortness of breath of unclear origin. No actual cases of airway obstructions were reported.
Spiegel and Raval reviewed 117 patients in 2005 for complications associated with UPPP.8 Ten patients were discharged the same day as the surgery. The remainder of the patients experienced a 4.3% incidence rate of respiratory complications. While most cases were due to oxygen desaturation, two patients developed airway obstruction from presumed laryngospasm at the time of extubation. Both of these patients developed postobstructive pulmonary edema within minutes of the obstruction.
Overall, the rate of airway obstruction appears to be in the range of 1.4–11%. Most importantly, obstruction events appear to occur immediately after surgery in the early phase of recovery, so it is not likely that an extended period of observation would be a useful way to prevent this type of complication.
Oxygen desaturation is also often cited as a common complication in OSA patients undergoing UPPP. A value of less than 85–93% is typically considered significant desaturation. In the past, some surgeons have advocated postoperative ICU monitoring for fear of serious desaturation events. However, such monitoring may not be reasonable since most desaturations occur in the early phase of recovery. Additionally, more mild nocturnal desaturations may continue for weeks, since UPPP does not correct OSA immediately.12
The fact that most occurrences of desaturations happen relatively early in the recovery process further supports same-day patient discharge for the majority of patients. For example, in a 2006 study by Hathaway and Johnson of 110 patients undergoing UPPP, desaturations in three patients all occurred in the recovery room.7 In the review by Spiegel and Raval, three desaturations below 90% were reported.8 The first desaturation occurred in the recovery room, the second on the first postoperative night and the third on the first postoperative day. The third patient likely desaturated on the first postoperative day because he was given narcotic patient-controlled analgesia (morphine) for pain, and narcotic analgesia tends to impede respiratory function.
Advocates of extended postoperative stays after UPPP also claim the need for post-surgical oxygen supplementation on the floor as an important argument for hospitalization. However, there is some evidence that there may not be a direct relationship between oxygen supplementation and lower desaturation rates. For example, Riley et al.13 found no significant difference in the postoperative low oxyhemoglobin saturation (LSAT) between patients receiving continuous positive airway pressure (CPAP) and the non-CPAP group.
A patient’s preoperative Respiratory Distress Index (RDI) may also be a poor predictor of whether or not they may desaturate, as was the case in the review by Hathaway and Johnson.7 While two of the admitted patients had RDIs over 50 (indicating severe OSA) one patient had an RDI of 22 and still desaturated. Desaturations occurred in the recovery room, and all patients were admitted into the hospital, but none required the ICU. The authors concluded that preoperative polysomnography data such as the RDI may not predict which patients will experience desaturation in the early postoperative period.
Overall, research shows that desaturation, particularly nocturnal desaturation, is a very common complication of UPPP surgery for OSA. In fact, it should be considered more of an expectation than a complication. Giving oxygen postoperatively may or may not make a difference, so admitting all UPPP patients in order to give them oxygen would not be reasonable. Also, preoperative sleep indices may not be an accurate indicator for identifying patients who may desaturate, so it would not be practical to hospitalize all patients due to fear of this complication. The most likely scenario is that if a serious desaturation occurs, it would be in the early phase of recovery, at which point the patient should be admitted to the hospital. Otherwise, minor nocturnal desaturations are to be expected since it may take a few weeks to note improvement in a patient’s OSA.
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