Two of our most
frequent topics have been opioid-induced postoperative respiratory depression
and perioperative obstructive sleep apnea (OSA). See the extensive list of our
prior columns at the end of todays column. This past month there have been a
number of significant articles pertinent to both conditions.
Well start with a
review of closed claims with postoperative opioid-induced respiratory
depression (Lee
2015). The authors searched the Anesthesia Closed Claims Project database
between 1990 and 2009 for cases likely to include postoperative opioid-induced
respiratory depression. They found 92 probable, possible or definite claims,
77% of which resulted in death or severe brain damage.
Most of the patients
were middle aged, obese and had low ASA scores. 16% had OSA diagnosed
preoperatively and another 9% were at high risk. Lower extremity orthopedic procedures
were overrepresented (41%).
Nearly half received
opioids via more than one modality and nearly half were on a continuous
opioid infusion at the time of the event. Morphine and fentanyl were the
two most commonly administered opioids. A third were also receiving non-opioid
sedating medications. Significantly, a third had more than one physician
prescribing opioids or other sedating agents. Just as significantly, only
16% were on doses of opioids that the reviewers thought were excessive.
Most events (88%)
occurred within 24 hours of the surgical procedure, 13% occurring within 2
hours of transfer from the postoperative recovery room. In 12 of the cases
nursing assessments had been done within 15 minutes prior to the event.
Importantly, 60% of patients had been described as somnolent, with or
without snoring, prior to the event. And reviewers felt that nursing checks
were inadequate in at least one respect in 31% of cases. Respiratory
monitors and pulse oximetry were in use in less than half, and none of
those were on telemetric pulse oximetry. Reviewers felt that 97% of the
events were possibly or probably preventable by better monitoring.
Their findings
suggest a substantial gap in understanding the signs and symptoms of this
opioid-related postoperative phenomenon. In particular, somnolence and
snoring were often underappreciated as critical signs of impending
respiratory depression. That was a point we noted in our February 12, 2013
Patient Safety Tip of the Week CDPH:
Lessons Learned from PCA Incident.
Its hoped that
reporting of incidents and near misses of such cases may improve our
understanding of all the factors involved in enabling these unfortunate events.
The most recent APSF Newsletter discusses the Obstructive Sleep Apnea (OSA)
Death and Near Miss Registry, which now accepts case reports (Posner 2015). That
article describes what is required in case reports and notes that case report
forms and instructions can be downloaded from the registry
website.
Following reports on
serious complications following tonsillectomy in children (Goldman
2013, Cote
2014) that implicated postoperative respiratory depression and obstructive
sleep apnea worsened by opioid therapy, there have been a number of editorials
about the elephant in the room. Brown and Brouillette (Brown
2014), commenting on the Goldman and Cote and other studies, discussed many
of the physiological aspects of respiratory depression and OSA and opioid
therapy in children. They note that not only do opioids blunt the ventilator
response to hypercarbia and hypoxemia and blunt the
arousal responses to OSA but they also note that hypoxemia reduces the dose of
narcotics required to alleviate pain in children.
While the Goldman,
Cote, and Brown papers dealt with pediatric patients, Benumof
(Benumof
2015) noted the bigger problem (the elephant in the room) involves
all patients undergoing all surgeries. He notes the prototypical dead in a
bed patient is an obese adult patient with severe OSA receiving opioids
postoperatively without continuous electronic monitoring, oxygen
supplementation or CPAP. He further calls attention to the creation of the
Obstructive Sleep Apnea (OSA) Death and Near Miss Registry mentioned above.
Brown and Brouillette, responding to Benumofs letter, again note that not all cases of OSA are
diagnosed before surgery and again mention the McGill Oximetry Score as a
potential tool that might be of use in screening (Benumof
2015). That system supplements a careful clinical assessment with
home nocturnal pulse oximetry. They acknowledge, however, that the tool needs
to be validated in a number of populations.
And, speaking of children, dont forget that the recent
warnings about use of codeine in children first originated after deaths of
pediatric patients receiving codeine after adenotonsillectomy
for OSA (see our Whats New in the
Patient Safety World columns for September 2012 FDA
Warning on Codeine Use in Children Following Tonsillectomy and March 2013 Further
Warning on Codeine in Children Following Tonsillectomy and our May 2014 Pediatric
Codeine Prescriptions in the ER). These highlighted the fact that those
patients with CYP2D6 ultrarapid metabolism
were especially prone to post-tonsillectomy respiratory depression and
suggested that codeine not be used in children undergoing adenotonsillectomy
for OSA.
Undoubtedly, the use of codeine after adenotonsillectomy
for OSA has diminished significantly after these reports and warnings. However,
that does not mean that there has been a switch to safer alternatives. Two
recent reports illustrate safety issues that have occurred with use of morphine
and tramadol, respectively, in children after adenotonsillectomy
for OSA. Kelly and colleagues conducted a prospective randomized clinical trial
in children who had sleep disordered breathing who were scheduled for
tonsillectomy with or without adenoid removal (Kelly
2015). Children were randomized to receive acetaminophen with either
oral morphine or oral ibuprofen. On the first postoperative night oxygen
desaturations were improved in 68% of the ibuprofen group vs. only 14% in the
morphine group. In fact, the number of desaturation events increased
substantially in the morphine group. There were no differences seen in
analgesic effectiveness, tonsillar bleeding, or adverse drug reactions. The
study was actually terminated early after the interim analysis demonstrated the
increased risks with morphine. The authors conclude that ibuprofen in
combination with acetaminophen provides safe and effective analgesia in children
undergoing tonsillectomy and that post-tonsillectomy morphine use may be unsafe
and its use should be limited.
The second paper (Orliaguet
2015) described a 5-year old boy who underwent adenotonsillectomy who received one oral 20 mg dose of tramadol and was brought back to the ED
the day after surgery with unresponsiveness, pin-point pupils, poor
respiration, and oxygen desaturation. He responded dramatically to noninvasive
ventilation and intravenous naloxone and fully recovered. CYP2D6 genotyping confirmed the
pattern associated with ultrarapid metabolism. Like
those in the first paper, the authors suggest use of NSAIDs as an alternative
to opioids in children with OSA undergoing tonsillectomy.
Unlike the case in
adults, where tools like STOP-BANG are often used to predict OSA, there is no
consensus on tools to predict OSA in children. In their study focusing on death
and neurological injuries following tonsillectomy Cote et al. concluded that at
least 16 children could have been rescued had respiratory monitoring been
continued throughout first- and second-stage recovery, as well as on the ward
during the first postoperative night (Cote
2014). Those authors stressed the need for a validated pediatric-specific
risk assessment scoring system to assist with identifying children at risk for
OSA. That might help determine which children are not appropriate to be cared
for on an outpatient basis. In our May
13, 2014 Patient Safety Tip of the Week Perioperative
Sleep Apnea: Human and Financial Impact we noted screening tools
for OSA have been of relatively little value in children (Wild
2014). The authors found that, though identifying 85% of children with
moderate to severe OSA, the American Society of Anesthesiologists screening
tool for moderate to severe OSA (MSOSA) had a 78% false positive rate. The
McGill Oximetry Score mentioned above (Brown
2014, Benumof 2015) is promising. It has a 97% positive
predictive value vs. polysomnography in children and may help identify severity
although an inconclusive study does not rule out milder OSA (Brown
2014). But its yet to be tested in a randomized, controlled trial. The
recently reported CHAT (Childhood Adenotonsillectomy)
study (Mitchell
2015) identified a number of clinical parameters that correlate with
severity of OSA. However, information on demographics, physical
findings, and questionnaire responses did not robustly discriminate different
levels of OSAS severity.
While we strongly recommend screening for OSA and
respiratory risk prior to surgery, it is probably not possible to identify all
patients at risk for respiratory depression when exposed to opioids. Therefore,
monitoring becomes critical. Our
Patient Safety Tips of the Week for February 19, 2013 Practical
Postoperative Pain Management and May 6, 2014 Monitoring
for Opioid-induced Sedation and Respiratory Depression discuss many of the
important clinical signs and symptoms and use of tools such as the Pasero Opioid-induced Sedation Scale (POSS) and the
Richmond Agitation and Sedation Scale (RASS). As above, we need to better
educate everyone on recognition of somnolence and snoring as danger signs. But
the Lee study (Lee
2015) and numerous anecdotal reports clearly show that episodic vital sign
monitoring is grossly inadequate in identifying postoperative respiratory
depression. Continuous monitoring is needed. In our March 26, 2013 Patient
Safety Tip of the Week Failure
to Recognize Sleep Apnea Before Surgery we noted
that means continuous monitoring of respiratory rate and pattern, oxygenation
status, and capnography. Capnography
has now become the standard of care for monitoring patients with OSA who are on
opioids. As in our February 12, 2013 Patient Safety Tip of the Week CDPH:
Lessons Learned from PCA Incident sidestream capnography used in unintubated
patients may not be particularly good at detecting hypercarbia
but is useful in monitoring respiratory rate and detecting apnea. And dont
forget that sedative/hypnotic drugs may also be dangerous in patients with OSA,
particularly when used in conjunction with opioids.
Monitoring is probably the most important aspect of care of
the patient with suspected OSA and there remain problems with the
threshold-based alarm systems most often used today. Lynn and Curry (Lynn 2011)
described 3 patterns of unexpected
in-hospital deaths (see our
February 22, 2011 Patient Safety Tip of the Week Rethinking
Alarms). The third pattern
they describe is one that is typically seen in sleep apnea. In this pattern one
sees repetitive reductions in airflow and oxygen saturation during sleep
followed by arousals. The arousals rescue the patient but eventually the
capacity or reserve of the patient to recover with arousals becomes impaired
(often in response to narcotics or sedatives) and the patient may experience sudden
death during sleep. The authors discuss the inability of currently used
oximeters to recognize this pattern. They even imply that this pattern may give
rise to oximeters alarming and being interpreted as false alarms attributed
to motion artifact, etc. because when staff respond to the alarm the patient is
now awake, breathing normally and has a normal oxygen saturation.
The issue of supplemental oxygenation is still much debated.
Weve mentioned on numerous occasions that supplemental use of oxygen may mask
impending respiratory depression, particularly in those patients not being
monitored with capnography, and may provide a false
sense of security.
The issue of perioperative
use of CPAP is also still in debate. If a patient has known OSA and has
been on CPAP at home, they should get CPAP post-operatively (preferably with
their own CPAP equipment brought in from home). But the evidence base for use
of CPAP, NIPPV, BiPAP, or APAP in those not
previously on CPAP at home is not robust. Our Patient Safety Tips of the Week for September 24, 2013 Perioperative
Use of CPAP in OSA and May 13, 2014 Perioperative
Sleep Apnea: Human and Financial Impact suggest that CPAP can be
effective in the perioperative period, though compliance with CPAP is
suboptimal. Meta-analyses of perioperative use of CPAP in OSA have recently
been presented in abstracts at national meetings by the Toronto group that has
done so much OSA research. The first suggests that there is a trend toward
significance in reducing postoperative adverse events in the CPAP-treated group
compared to the non-CPAP group but still acknowledges that further research is
needed on the value of perioperative CPAP (Nagappa 2014a). The
second (Nagappa 2014b) suggests that perioperative CPAP
significantly reduces perioperative AHI (apnea-hypopnea index). Length of stay
was not significantly shortened in OSA patients on CPAP undergoing surgery, but
this may be due to the small number of patients in the analysis.
Postoperative opioid-induced respiratory depression remains
a significant problem and one that is very much preventable. Better recognition
of at-risk patients and careful monitoring strategies are needed to prevent
this adverse event.
Other Patient Safety
Tips of the Week pertaining to opioid-induced respiratory
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
January 4, 2011 Safer
Use of PCA
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
Tools: PCA
Pump Audit Tool and the PCA
Pump Criteria
Our prior columns on
obstructive sleep apnea in the perioperative period:
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
References:
Lee LA, Caplan RA, Stephens LS, et al. Postoperative Opioid-induced
Respiratory Depression: A Closed Claims Analysis. Anesthesiology 2015; 122:
659-665
http://anesthesiology.pubs.asahq.org/Article.aspx?articleid=2087871
Posner KL, Bolden N.
Obstructive Sleep Apnea Death and Near Miss Registry Opens. APSF Newsletter
2015; 29(3): 53, February 2015
http://www.apsf.org/newsletters/pdf/Feb2015.pdf
registry website: http://depts.washington.edu/asaccp/projects/obstructive-sleep-apnea-osa-death-near-miss-registry
Goldman JL, Baugh
RF, Davies L, et al. Mortality and major morbidity after tonsillectomy:
Etiologic factors and strategies for prevention. Laryngoscope 2013; 123(10):
2544-2553
http://onlinelibrary.wiley.com/doi/10.1002/lary.23926/abstract
Cote CJ, Posner KL, Domino KB. Death or Neurologic Injury After Tonsillectomy in Children with a Focus on Obstructive
Sleep Apnea: Houston, We Have a Problem! Anesth Analg 2014; 118(6): 1276-1283, Published Ahead-of-Print 10
July 2013
Brown KA, Brouillette RT. The Elephant in the Room: Lethal Apnea at
Home after Adenotonsillectomy. Anesthesia &
Analgesia 2014; 118(6): 1157-1159
Benumof JL. The Elephant in the Room Is Bigger Than
You Think: Finding Obstructive Sleep Apnea Patients Dead in Bed Postoperatively.
Anesthesia & Analgesia 2015; 120(2): 491, February 2015
Kelly LE, Sommer DD, Ramakrishna J, et al. Morphine or Ibuprofen for
Post-Tonsillectomy Analgesia: A Randomized Trial. Pediatrics 2015; 135(2): 307-313 published ahead of print
January 26, 201
Orliaguet G, Hamza J, Couloigner
V, et al. A Case of Respiratory Depression in a Child with Ultrarapid
CYP2D6 Metabolism After Tramadol. Pediatrics 2014; Published online
February 2, 2015
http://pediatrics.aappublications.org/content/early/2015/01/28/peds.2014-2673.abstract
Wild D. OSA Screener
of Limited Clinical Use in Children, Study Finds. Anesthesiology News 2014;
40:4 April 2014
http://www.anesthesiologynews.com/ViewArticle.aspx?d=PRN&d_id=21&i=April+2014&i_id=1050&a_id=26233
Mitchell RB, Garetz S, Moore RH, et al. The Use of Clinical Parameters
to Predict Obstructive Sleep Apnea Syndrome Severity in ChildrenThe
Childhood Adenotonsillectomy (CHAT) Study Randomized
Clinical Trial. JAMA Otolaryngol Head Neck Surg 2015; 141(2): 130-136
http://archotol.jamanetwork.com/article.aspx?articleid=2020429
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
Nagappa M, Wong D, Wong J, Chung F. Effects Of
Continuous Positive Airway Pressure On Postoperative Adverse Events In
Obstructive Sleep Apnea Patients Undergoing Surgery. A Systematic Review and
Meta-Analysis. IARS 2014 Annual Meeting Sessions
http://conference-cast.com/IARS/common/media-player.aspx/3/16/152/324
Nagappa M, Mokhlesi B,
Wong J, et al. Effects of CPAP on Apnea Hypopnea Index & Length of Hospital
Stay in OSA Patients Undergoing Surgery: A Meta-analysis. ASA Annual Meeting
2014; Abstract A4012; October 14, 2014
Print PDF
version
http://www.patientsafetysolutions.com/