Patient Safety Tip of the Week
August 18, 2015 Missing
Obstructive Sleep Apnea
Our numerous columns
on obstructive sleep apnea (OSA) have focused heavily on patients undergoing
surgery (see the list of columns at the end of todays column). But we know
that OSA is highly prevalent in the general population and even more so in
hospital inpatients. In our July 2010 Whats New in the Patient Safety
World column Obstructive
Sleep Apnea in the General Inpatient Population we noted a study using the STOP and Berlin questionnaires
found a potential 60% prevalence of obstructive sleep apnea in patients
admitted to general medicine units in an urban academic hospital, most of whom
had never been diagnosed with OSA. Many of the patients were obese and most had
comorbidities. A high percentage of these patients received intravenous
narcotics or were prescribed benzodiazepines or both and none of these received
any supplemental respiratory monitoring. The study highlights the risk of using
such medications in potentially high risk patients and also highlights the
potential benefits of using simple tools like STOP in identifying potential OSA
candidates.
Now another study in
a general medical (nonsurgical) inpatient population has confirmed a very high
prevalence of OSA (Sharma 2015).
Sharma and colleagues evaluated 754 consecutive medical inpatients who had a
BMI ≥ 30 with the STOP
questionnaire and overnight pulse oximetry. Of these, 636 were deemed to be at
high risk for OSA. Subsequent polysomnography was performed on 149 patients and
87% of these had confirmation of OSA. They suggest that the use of the STOP
questionnaire plus the overnight pulse oximetry may be a useful strategy to
identify at-risk patients, a strategy similar to one previously suggested by
Chung and colleagues (see our May 22, 2012 Patient Safety Tip of the Week Update
on Preoperative Screening for Sleep Apnea).
Another recent study in nonsurgical patients looked at sleep disordered breathing (SDB) in heart
failure patients (Khayat 2015).
The researchers found in over 1000 patients admitted with acute heart failure
and LVEF ≤ 45% and not already
diagnosed with SDB that 47% had obstructive sleep apnea (OSA) and 31% had central
sleep apnea. They then followed those who survived to discharge to assess
long-term mortality. They found that both central sleep apnea and obstructive
sleep apnea were independently associated with post-discharge mortality. The
same researchers had previously found sleep disordered breathing to be a risk
factor for rehospitalization in patients with heart
failure (Khayat
2012). Exploratory analysis
in the 2015 study suggested that treatment of SDB leads to survival similar to
those without SDB.
Litigation related
to perioperative complications in patients with OSA seems to be increasing (Fouladpour
2015). Those researchers found most cases reaching verdicts in
malpractice cases were relatively young (average age 41.7 years) and male
(63%). Complications occurred intraoperatively in 21%, in the PACU in 33%, and
on surgical floors in 46%. The most common complications were respiratory
arrest in an unmonitored setting and difficulty in airway management. Opioids
were felt to play a role in 38% of cases and general anesthetics in 58%. Death
occurred in 71% of the cases reviewed. Most cases were elective and some were
relatively minor procedures (eg. dental extraction,
revision of a pacemaker lead). The average financial penalty was $2.5 million
in cases where the plaintiff prevailed. The authors discuss the importance of
postoperative monitoring in patients with OSA. They also, however, note that problems
related to airway management and premature extubations
were frequent. They note that ASA guidelines recommend tracheal extubation while the patient is awake and only once
neuromuscular blockade has completely resolved, and in the semiupright
or lateral position. They conclude that perioperative complications related to
OSA are increasingly being reported as the central contention of malpractice
suits. These cases can be associated with severe financial penalties.
Another recent study (Weingarten
2015) looked at patients who needed naloxone to reverse opioid-induced
respiratory depression or sedation within 48 hours after discharge from
anesthetic care (transfer from the postanesthesia
care unit or transfer from the operating room to postoperative areas). While
they found that a respiratory event in the PACU increased the risk of needing
naloxone rescue 5-fold, they also found that obstructive sleep apnea (OSA)
increased the risk 2.45 fold. Their findings suggest that these patients may
benefit from more careful monitoring after being discharged from anesthesia
care.
Long at the top of our list of hospital-based patient safety
issues is opioid-induced respiratory depression (see the list below of our
previous columns on opioid-related respiratory depression). Opioid use in the
hospital setting is substantial and its not just surgical patients who are
receiving opioids. In our May 6, 2014
Patient Safety Tip of the Week Monitoring
for Opioid-induced Sedation and Respiratory Depression we noted that over
half (51%) of medical inpatients receive opioids, often in high doses (Herzig 2014).
And while parenteral opioids have received the most attention, opioids
delivered via any route may contribute to respiratory depression, particularly
in at-risk patients.
So knowing that a patient has OSA is extremely important in
preventing disastrous outcomes. We keep coming back to a study by Lynn and
Curry (Lynn
2011) that we discussed in our February 22, 2011 Patient Safety Tip of the
Week Rethinking
Alarms. That article cited 3 patterns of unexplained inpatient deaths, one
of which is characteristic of patients with OSA.
But to complicate things even more, a new study from Frances
Chung and her colleagues in Toronto shows that a substantial number of patients
without preoperative sleep apnea develop moderate-to-severe sleep disordered
breathing (SDB) after surgery (Chung
2015). Patients were invited to undergo sleep studies with a portable
device preoperatively at home and postoperatively on the first and third night
after surgery in the hospital or at home. Of 120 patients who did not have
sleep apnea on the preoperative study, 31 (25.8%) were found to have AHI >
15 events/h on postoperative night 1 and/or postoperative night 3. These were
mostly driven by obstructive apneas and hypopneas rather than central apneas. Age
and preoperative respiratory disturbance index (RDI) were significantly
associated with the occurrence of postoperative moderate-to-severe SDB.
The Chung study basically warns us that even patients who have previously tested negative for OSA may still be
at risk for OSA when undergoing surgery. The authors note that fluid shifts
or medications (opioids or sedatives) may increase the apnea-hypopnea index.
They noted that patients in the post-op SDB group were more prone to upper
airway collapse in the supine position, which is common after surgery. They
note that many may have had undetected upper airway resistance syndrome. They
also suggested that the preoperative respiratory disturbance index (RDI) might
be of value in predicting which patients will develop post-op SDB but note that
further validation is necessary.
In our May 13, 2014
Patient Safety Tip of the Week Perioperative
Sleep Apnea: Human and Financial Impact we noted a study (Roggenbach 2014) that looked at breathing patterns in 37
patients undergoing major surgery who had not already been diagnosed with OSA. While
59% of the patients had abnormal nocturnal breathing patterns (AHI = 5
or higher) on the pre-op night, they found increases on the third through sixth
nights being significant. Previous observations had demonstrated a delayed
increase in OSA after surgery, usually in conjunction with the return of REM
sleep on the second or third post-op day. But this appears to be the first
study to monitor for a longer duration and it shows a substantial increase in
the risk of OSA in the late post-op period. Those authors speculate that the
surgery itself may have a modulating effect on nocturnal breathing patterns.
Their patients underwent major prostate or abdominal surgeries. They note that
such surgeries are regularly associated with substantial fluid accumulation and
speculate that peripharyngeal soft tissue edema might
contribute to reduced airway patency.
Conventional wisdom has been that about 90% of patients with
OSA have not yet been diagnosed as having OSA. While the screening methods
noted above to identify patients with OSA make sense, inpatients would have
already spent at least one night at risk while getting their pulse oximetry. We
still think doing the STOP or STOP-Bang questionnaire is advisable but its
obvious we will still miss some cases of
OSA. And, given the new findings from Chung and colleagues, we cant even
be sure that patients with a previous sleep study negative for OSA wont have
OSA while an inpatient.
The bottom line is that appropriate monitoring is needed for
any inpatient you intend to treat with opioids or sedative agents. And, as per
our multiple columns on opioid-induced respiratory depression (see list below),
assessing the patients level of arousal before and after doses of such drugs
is important but obviously cant be done on a continuous basis. Weve also
noted numerous times that patients with OSA, when wakened, likely have a normal
level of arousal and normal oxygen saturation. Monitoring with only pulse
oximetry in inadequate and leads to a false sense of security. So you really
need to monitor such patients with capnography or
apnea monitoring.
Just about every hospital weve been to can recall a patient
who died suddenly and unexpectedly (found dead in a bed). And when such cases
are analyzed we usually find they had risk factors for OSA and were receiving
opioids or sedative agents without monitoring. So dont just consider
opioid-induced respiratory depression a problem on surgical services. You
probably have just as many patients on medical services that are at risk.
Some of our prior
columns on obstructive sleep apnea:
June 10, 2008 Monitoring
the Postoperative COPD Patient
August 18, 2009 Obstructive
Sleep Apnea in the Perioperative Period
August 17, 2010 Preoperative
Consultation Time to Change
July 2010 Obstructive
Sleep Apnea in the General Inpatient Population
July 13, 2010 Postoperative
Opioid-Induced Respiratory Depression
November 2010 More
on Preoperative Screening for Obstructive Sleep Apnea
February 22, 2011 Rethinking
Alarms
November 22, 2011 Perioperative
Management of Sleep Apnea Disappointing
March 2012
Postoperative
Complications with Obstructive Sleep Apnea
May 22, 2012 Update
on Preoperative Screening for Sleep Apnea
February 12, 2013 CDPH:
Lessons Learned from PCA Incident
February 19, 2013 Practical
Postoperative Pain Management
March 26, 2013 Failure
to Recognize Sleep Apnea Before Surgery
June 2013 Anesthesia
Choice for TJR in Sleep Apnea Patients
September 24, 2013 Perioperative
Use of CPAP in OSA
May 13, 2014 Perioperative
Sleep Apnea: Human and Financial Impact
March 3, 2015 Factors
Related to Postoperative Respiratory Depression
Our other columns
pertaining to opioid-induced respiratory depression:
- January
4, 2011 Safer
Use of PCA
- July
13, 2010 Postoperative
Opioid-Induced Respiratory Depression
- May
12, 2009 Errors
With PCA Pumps
- September
21, 2010 Dilaudid
Dangers
- November
2010 More
on Preoperative Screening for Obstructive Sleep Apnea
- February 22, 2011 Rethinking
Alarms
- May 17, 2011 Opioid-Induced
Respiratory Depression Again!
- September 6, 2011 More
Tips on PCA Safety
- December 6, 2011 Why
You Need to Beware of Oxygen Therapy
- February
21, 2012 Improving
PCA Safety with Capnography
- September 2012 Joint
Commission Sentinel Event Alert on Opioids
- September 2012 FDA
Warning on Codeine Use in Children Following Tonsillectomy
- July 3, 2012 Recycling
an Old Column: Dilaudid Dangers
- February 12, 2013 CDPH:
Lessons Learned from PCA Incident
- February 19, 2013 Practical
Postoperative Pain Management
- May 6, 2014 Monitoring
for Opioid-induced Sedation and Respiratory Depression
- March 3, 2015 Factors
Related to Postoperative Respiratory Depression
- June 2, 2015 Reminders
of Dilaudid Dangers
- August 11, 2015 New
Oxygen Guidelines: Thoracic Society of Australia and NZ
- Tools:
PCA
Pump Audit Tool and the PCA
Pump Criteria
References:
Sharma S, Mather PJ, Efird JT, et
al. Obstructive sleep apnea in obese hospitalized patients: a single center
experience. J Clin Sleep Med 2015; 11(7): 717723
http://www.aasmnet.org/jcsm/ViewAbstract.aspx?pid=30090
Khayat R, Jarjoura
D, Porter K, et al. Sleep disordered breathing and post-discharge mortality in
patients with acute heart failure. Eur Heart J 2015;
36(23): 1463-1469 First published online: 30
January 2015
http://eurheartj.oxfordjournals.org/content/36/23/1463
Khayat R, Abraham W, Patt B, et al. Central sleep apnea is a predictor of
cardiac readmission in hospitalized patients with systolic heart failure. J Card Fail 2012; 18: 534-540
http://www.onlinejcf.com/article/S1071-9164%2812%2900154-6/abstract
Fouladpour N, Jesudoss
R, Bolden N. et al. Perioperative Complications in Obstructive Sleep Apnea
Patients Undergoing Surgery: A Review of the Legal Literature. Anesthesia &
Analgesia 2015; Published ahead of print June 23, 2015
Weingarten TN, Herasevich V, McGlinch MC, et al. Predictors of Delayed Postoperative
Respiratory Depression Assessed from Naloxone Administration. Anesth Analg 2015; 121(2):
422-429
Herzig SJ, Rothberg MB, Chekung M, et al. Opioid utilization and opioid-related
adverse events in nonsurgical patients in US hospitals. Journal of Hospital
Medicine 2014; 9(2): 73-81
http://onlinelibrary.wiley.com/doi/10.1002/jhm.2102/abstract
Lynn LA, Curry JP. Patterns of unexpected in-hospital
deaths: a root cause analysis. Patient Safety in Surgery 2011, 5:3
(11 February 2011)
http://www.pssjournal.com/content/pdf/1754-9493-5-3.pdf
Chung F, Liao P, Yang Y, et al. Postoperative
Sleep-Disordered Breathing in Patients Without Preoperative Sleep Apnea. Anesth Analg 2015; 120(6): 1214-1224
Roggenbach
J, Saur P, Hofer S, et al. Incidence of
perioperative sleep-disordered breathing in patients undergoing major surgery:
a prospective cohort study. Patient Safety in Surgery 2014; 8: 13
http://www.pssjournal.com/content/8/1/13
Print PDF
version
http://www.patientsafetysolutions.com/