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(Gupta et al, 2001 Level III‐3). However, after outpatient surgery, a preoperative diagnosis of OSA
was not associated with an increase in adverse events or unplanned hospital admission (Sabers
et al, 2003 Level III‐3).
Differences in the incidence of oxygen desaturation have also been reported. A study of 2467
patients used three different screening tools to determine if patients were at risk of OSA and
reported an incidence of patients at high risk of OSA of between 28% and 33%, depending on
the tool used; of the 416 patients consenting to the study, those identified as high risk were
also more likely to develop postoperative complications (Chung, Yegneswaran et al, 2008
Level III‐2). Similarly, screening of 2206 patients reported that 11% were at high risk of having
OSA; data from 115 of these OSA‐risk patients showed that they had a higher incidence of
episodes of oxygen desaturation (Gali et al, 2007 Level III‐2).
One of the main concerns in patients with OSA is that administration of opioids for the
treatment of acute pain may lead to an increase in the number and severity of obstructive
episodes and oxygen desaturation.
Opioid administration in the postoperative period is known to lead to episodes of pronounced
oxygen desaturation while the patient is asleep, which are much more commonly a result of
obstructive and central apnoea than a decrease in respiratory rate (Catley et al, 1985 Level III‐2;
Clyburn et al, 1990 Level III‐3).
However, there remains a paucity of information regarding the effects of analgesics, including
opioids, in the acute pain setting in patients with OSA, and therefore limited data on which to
base recommendations for their postoperative care (Blake et al, 2008; Gross et al, 2006; Chung,
Yuan et al, 2008).
A comparison of patients assessed (by history, body mass index and physical examination) to
be at risk of having OSA (n = 33) with control patients (n = 30) has shown that patients
classified as OSA risk have more obstructive events in the postoperative period (Blake et al,
2008 Level III‐2). All patients were continuously monitored for 12 hours during the first
postoperative night. Those classified as OSA risk had significantly more episodes of obstructive
apnoea than control patients (39±22 vs 14±10 events/ hour) and spent more time with oxygen
saturation levels lower than 90% (Blake et al, 2008 Level III‐2). There was no difference between
the groups in the cumulative morphine dose over that time or frequency of central and mixed
apnoeas (Blake et al, 2008 Level III‐2). The correlation between a classification of high risk for
OSA and a high number of oxygen desaturation each hour was also reported in patients
monitored for 48 hours after surgery (Gali et al, 2009) Level III‐3).
CHAPTER 11 reports, the use of opioid medications in patients with OSA appeared to be a common factor
Evidence of the risks associated with analgesia and OSA is very limited. In a number of case
in most of the cases where complications, including death, have been reported following
intermittent IM, patient‐controlled IV and epidural analgesia (Reeder et al, 1991; VanDercar et al,
1991; Etches, 1994; Ostermeier et al, 1997; Cullen, 2001; Lofsky, 2002; Parikh et al, 2002). However,
caution is required when interpreting these reports. Most of the cases involved what appear
to be excessive opioid doses (eg excessive bolus dose or a background infusion with PCA)
and/or inadequate monitoring for respiratory depression (eg it appeared here was an over‐
reliance on respiratory rate; sedation levels were not checked and/or increasing sedation was
not recognised as an early indicator of respiratory depression) and/or protocol failures and/or
concurrent administration of sedatives (Macintyre, 2005).
A report by an American Society of Anesthesiologists task force looking at the perioperative
management of patients with OSA concluded that there was no good evidence that can be
used to evaluate the effects of various postoperative analgesia techniques in patients with
OSA (Gross et al, 2006) and no good comparisons between pure agonist opioids such as
412 Acute Pain Management: Scientific Evidence
