Discussion
OSA is a common disorder caused by disruption to breathing during sleep
due to recurrent collapse of the pharyngeal airway leading to hypopnoea
or apnoea events which has both short term and long term health effects
(17). Studies of patients with OSA have demonstrated an increased risk
of post-operative complications including respiratory and cardiac events
such as myocardial infarction or cardiac arrhythmias and patients are
more likely to require intensive care input (2, 18, 19). A sensitivity
to narcotics resulting in respiratory depression and desaturations is
also a recognised complication among this cohort of patients which
usually results in increased post-operative monitoring in at least a
high-dependency setting (20).
However, with progress in day surgery, the Association of Anaesthetists
and the British Association of Day Surgery have published a consensus
document recognising that not all OSA patients need overnight monitoring
and selected patients can be safely discharged the same day (1). These
guidelines do advise certain considerations such as avoiding
postoperative opioid medications, use of regional anaesthesia if
possible, optimising comorbid conditions, the post-operative use of a
CPAP device if patients were already utilising one and a postoperative
review prior to discharging the same day. Some of these considerations
are difficult to achieve in upper airway surgeries and the risk of
airway complications or respiratory events are higher than in other
surgeries.
Our review indicates that despite the majority of the patients falling
into the moderate or severe OSA category and having upper airway
surgery, almost half of the patients were discharged on the same day
with minimal respiratory events either in the immediate post-operative
period or during follow-up in the form of readmissions. Oxygen
desaturations were the most commonly reported respiratory event and
these were often managed with oxygen supplementation with no further
complications observed during the remainder of the inpatient stay. This
would suggest that this group of patients can be safely monitored in an
area with continuous monitoring and increased nurse to patient ratio,
but not necessarily needing intensive care or high dependency input.
Major airway complications such as laryngospasms were almost always
picked up immediately post-extubation and this would prompt
post-operative care in a more appropriate setting. There was no
mortality reported among the 1836 patients in this review.
Major respiratory events following nasal and palatopharyngeal surgery
for OSA are rare. Concurrent tongue base surgery however, can be
associated with more serious respiratory events and in these patients,
overnight observation would be prudent.
One large study evaluated a North American database for morbidity and
mortality following uvulopalatopharyngoplasty (UPPP) (n = 1096) and
multilevel sleep surgery (n = 1578) for OSA (3). The multilevel sleep
surgery included patients who had UPPP in addition to other procedures
(including tonsillectomy and adenoidectomy, tongue and mouth surgery,
epiglottidectomy, glossectomy, limited pharyngectomy, hyoid myotomy and
suspension, excision of lingual tonsil, neurostimulators (intracranial)
procedures, reconstruction of lower jaw, other unspecified procedure).
They reported a total of four (0.15%) deaths within 30 days of surgery:
one death in the UPPP only group (0.09%), and three deaths following
UPPP with concomitant procedures (0.19%). There were no reported
details of the cause and timing of deaths. It is therefore not clear if
the risk of death is an issue in performing such cases as a daycase
surgery.
The findings from the systematic review was limited by a lack of
well-designed prospective studies with pre-defined discharge criteria
and a comprehensive assessment of complications such as continuous pulse
oximetry monitoring among all patients. Given patients were not all
systematically followed-up on discharge, it is unclear if there were any
significant respiratory events out of hospital or if patients presented
to other hospitals with complications. There was limited data on the
post-operative use of CPAP which is important given issues around nasal
packing and CPAP compliance. There was also significant heterogeneity in
the methodology of the studies and thus no inferential statistics could
be performed. None of the included studies were conducted in the United
Kingdom and this may limit the applicability of the results to a UK
population.
The included studies have shown that it is feasible to perform upper
airway surgeries in carefully selected patients with OSA as day cases.
Table 4 is a summary of the characteristics of daycase patients from
studies that have specified them. Patients with mild to moderate OSA and
no cardiopulmonary comorbidities were performed as day cases if there
were no concurrent tongue surgery. However, most had a post-operative
review prior to final discharge decision. Those that had episodes of
desaturations (<94% on room air) in recovery, had inadequate
oral intake or needed strong opioids for pain relief were admitted for
further observation.
There is a need for further well-designed prospective studies with clear
criteria for daycase patients and those needing an overnight admission.
Such studies should capture information on perioperative CPAP use, have
a comprehensive assessment of postoperative complications including
readmissions to other hospitals.