Developing a Perioperative
Obstructive Sleep Apnea Safety
Program
Wm. Charles Sherrill, Jr. M.D.
Medical Director, Novant Health Sleep
Tennessee Sleep Society
October 4, 2013
Making healthcare remarkable
Screening Tools for OSA
Sleep Disordered Breathing
 Simple snoring
 Upper airway resistance syndrome (UARS)
 Obstructive sleep apnea
 Central sleep apnea with or without Cheyne-Stokes
Respirations
 Complex sleep apnea
 Unobstructive hypoventilation
Clinical Scenario
45 year old male, 320 lbs and 5’11” had a rotator cuff repair
under general anesthesia. The intraoperative course was
uneventful. He was admitted to the ward for overnight
pain control.
Four hours after surgery, he received an intramuscular
injection of Meperidine 100 mg with Phenergan 25 mg.
This was repeated 3 hours later when severe pain
prevented him from sleeping.
Two hours later, nurses making a routine check found him
to be in full arrest. He could not be resuscitated. The
internist’s history and physical mentioned his having
been diagnosed with sleep apnea.
Ann Lofsky. M.D. Sleep Apnea and Narcotic Postoperative Pain Medication: A Morbidity and Mortality Risk
OSA and the Surgical Patient
Malpractice cases involving Obstructive Sleep
Apnea in Hospitalized Patients
– Intubation complications (20%)
– Extubation difficulties (10%)
– Post operative catastrophes (70%)
 Drug induced respiratory arrest resulting in death/brain damage
 Patients with OSA with inadequate monitoring
OSA and the Surgical Patient
Postoperative catastrophes (“Dead in bed”)
 Severe OSA
 Morbid obesity
 Isolated ward room
 No monitoring
 Receiving narcotics
 Off O2/PAP
Jonathan L. Benumof, M.D.
The Balance of Forces (Malhotra & White, 2002)
OSA and the Surgical Patient
Obstructive Sleep Apnea
As a consequence of the previous factors patients with
OSA are increasing dependent on the activity of the
pharyngeal dilator muscles for airway patency.
 OSA patients demonstrate increased EMG activity in the
pharyngeal dilator muscles (Genioglossus muscle) during
wakefulness.
 The reduction in EMG activity in these muscles at sleep onset is
greater in OSA patients than normals.
 OSA patients have a reduced ability to compensate for factors
that predispose them for upper airway collapse
– Increased negative pharyngeal pressures during inspiration
– Reductions in upper airway muscle tone
OSA and the Surgical Patient
Impact of sedatives, anesthetics, and analgesics
(opioids) on respiratory function
– Dose dependent depression of muscle activity of the upper airway muscles
 Depression of central respiratory output/upper airway reflexes
– Increased collapsibility of the upper airway
 Direct action (peripheral) on hypoglossal (tongue) and phrenic
(diaphragm) nerves
– Phrenic nerve depression – decreases in lung volume
 Alterations in apneic threshold/sensitivity to hypoxemia
 Alterations in the chemical/metabolic/behavioral control of
breathing
OSA and the Surgical Patient
Sympathetic nervous system activation (catecholamine excess)
 Surgical stress
 Hpoxemia/Hypercarbia
 Arousals
Related to an increased risk of cardiac arrhythmias, cardiac
ischemia and hypertension .
Majority of unexpected and unexplained postoperative deaths
occur at night and within 7 days of surgery. Rosenberg, J. et al British Journal
of Surgery 1992.
OSA and the Surgical Patient
Postoperative factors:
 Pain management: use of opioids
 Positioning: supine position
 Sleep fragmentation with potential REM rebound
 Comorbid conditions
OSA and the Surgical Patient
What is the scope of the problem?
How does the surgical process affect individuals with obstructive
sleep apnea?
Does Obstructive sleep apnea result in postoperative
complications more frequently than the non-OSA surgical
population?
Obesity Trends* Among U.S. Adults
BRFSS, 1990, 1998, 2007
(*BMI 30, or about 30 lbs. overweight for 5’4” person)
1990
1998
2007
No Data
<10%
10%–14%
15%–19%
20%–24%
25%–29%
≥30%
OSA and the Surgical Patient
Critical points of the NHANES data
 Prevalence of clinically severe obesity is increasing much faster than that of
moderate obesity.
Strum, R. Increase in morbid obesity in the USA. Public Health 2007, 121(7), 492496. Data from 2000-2005.
 BMI > 40 kg/m2 has increased fivefold
 1:200 adults to 1:33 adults
 BMI > 50kg/m2 has increased tenfold
 1:2,000 adults to 1:200 adults
OSA and the Surgical Patient
Prevalence of undiagnosed obstructive sleep apnea among adult
surgical patients in an academic medical center. Finkel, K. et. al.
Sleep Medicine. 2009. 10, 753-758.
Prospective, observational study.
ARES screening questionnaire
 661/2877 (23.7%) screened positive high risk for OSA.
 534 /661 (82%) screened positive no previous diagnosis of OSA
 207/661 valid 2 night HST
 73/207 (35%): moderate to severe OSA
OSA and the Surgical Patient
The STOP-BANG Questionnaire Identified the Patients with Significant Exacerbations of
Sleep Disordered Breathing during the Perioperative Period. P. Liao et al.
 67 patients: STOP-BANG + limited channel testing
– 20 low risk : Score < 3; 47 high risk: Score >3
– High Risk patients
 Pre operative AHI 10.2/hr.
 PON 1
AHI 13.2/hr.
 PON 3
AHI 23.2/hr.
 PON 5
AHI 17.9/hr.
 PON 7
AHI 16.0/hr.
– STOP-BANG 6-8 predictive of patients with higher AHI
OSA and the Surgical Patient
Kaw, R. et al. Chest 2012; 141(2); 436-441
 IM preop assessment and PSG databases crossmatched to
identify patients underwent both PSG and non cardiac surgery.
– 1784 pts , 471 pts eligible for study: 269 (57%) had OSA
– Presence of OSA associated with:
 Increased incidence of significant hypoxia (p=0.02)
 Reintubation (p=0.048)
 Unplanned ICU transfer (OR=7.6)
 Overall complications (OR=9.9)
 Longer length of hospital stay (OR=1.9)
OSA and the Surgical Patient
Postoperative complications
 Higher reintubation rates
 Hypoxemia / Hypercarbia
(+)/(-)
(+)
 Arrhythmias
 Myocardial ischemia
 Increased transfers to higher level of care (+)/(-)
 Increased length of hospitalization (+)/(-)
 Delirium
 Reationship to severity of OSA (AHI) (+) / (-)
OSA and the Surgical Patient
Screening Tools for OSA
Prevalence of obstructive sleep apnea appears to be increasing in
association with the increase in obesity. The prevalence of
obstructive sleep apnea in individuals presenting for surgery will be
increasing in the future.
Results would suggest that currently approximately 25%-30% of
indviduals presently for surgery will screen positive for obstructive
sleep apnea. (Based primarily on screening questionnaires).
These patients are at increased risk for complications and death that
may be reduced with appropriate screening, diagnosis and therapy.
**Clinical Management Strategy**
 Preoperative Screening (Identification)
 Flag patients with positive screen
 Monitoring (Keeping the patient safe)
 Decide on a monitoring strategy
 Have an action plan
 Measure outcomes
 Discharge (Longitudinal evaluation and care)
OSA and the Surgical Patient
OSA patients will present for surgery in one of three
ways:
 Known OSA compliant with therapy
 Known OSA
– Mild OSA – therapy not recommended
– Refused therapy or non compliant
– Therapy instituted – weight loss, surgery, dental appliance: status
unknown
 Unrecognized OSA
– Goal: Minimize the number of these patients presenting for surgery
OSA and the Surgical Patient
Screening Tools for OSA
Why do we need a mechanism for screening?
 F. Chung. Proportion of Surgical Patients with Undiagnosed
Obstructive Sleep Apnoea. BJA 2013
– 819 pts (surgical population) underwent a sleep study: 234 pts in lab PSG; 585 pts 10 channel HST
 Surgeons/anesthesiologists not informed of PSG results. Clinical diagnosis of
OSA made by physician noted by record review.
– 138/819 patients had severe OSA (AHI > 30) (17%)
 118/138 (86%) were not identified by surgeons
 65/138 (47.1%) were not identified by anesthesia
OSA and the Surgical Patient
Screening Tools for OSA
Criteria for Screening Tests
 Disease features
– Disease significantly impacts public health
– Intermediate probability of disease
– Detection occurs before a “critical point”
 Critical point occurs before clinical diagnosis
 Critical point occurs in time to affect outcome
 Test features
– High test sensitivity to detect minimal disease
– High test specificity to minimize false positives
– Screening test tolerated by patients
OSA and the Surgical Patient
Screening Tools for OSA
Important features:
 Easy to understand
 Ease of administration/scoring
 Limited time requirements
 Sensitivity/Specificity
 Validated (PSG)
 Generalizable to various patient populations
– Primary care, surgical, medical, sleep clinic
OSA and the Surgical Patient
Screening Tools for OSA
Purpose of OSA Screening (Identification)
 Eliminate or markedly reduce the unrecognized OSA patients present in a given
clinical population
 Stratify patients s relates to OSA risk; those at high risk expedited evaluation and
treatment or higher acuity of monitoring.
 Early identification and treatment may have positive impact on associated comorbid
conditions
 Limitation: Screening does not discriminate between mild and moderate/severe OSA.
Does not identify true “at risk” patients.
OSA and the Surgical Patient
Screening Tools for OSA
Screening Questionnaires
 Berlin Questionnaire
 ASA Checklist
 STOP and STOP-BANG questionnaire
 Sleep Apnea Clinical Score (SACS) (Flemons)
 Perioperative Sleep Apnea Prediction Score (P-SAP)
Sundar, E., Chang, J., Smetana, G. (2011). Perioperative Screening for
and Management of Patients with Obstructive Sleep Apnea. Journal
of Clinical Outcomes Management, 18(9), 399-411
OSA and the Surgical Patient
A Higher Score on STOP-BANG was Associated with a Higher
Incidence of Post-Operative Complications. F. Chung, P.
Liao
 862 pts: STOP-BANG and overnight HST (10 channel)
 STOP-BANG Complications:
All
Exclude SaO2
– 0-2 (25%)
39.9%
4.2%
– 3-5 (62%)
54.3%
14.2%
– 6-8 (13%)
66.1%
18.3%
– Associated with higher AHI post operatively
 Both cardiac and pulmonary complications increased with
increasing score; not neurologic
OSA and the Surgical Patient
Screening Tools for OSA
The STOP-BANG Equivalent Model and Prediction of
Severity of OSA: Relation to PSG Measurements of the
AHI.
Farney, R. et. al. Jr of Clinical Sleep Medicine, 2011, Vol 7, No 5, 459-65.
1426 pts clincal data converted to SB with PSG
This study looked at the probabilities of no, mild, moderate, severe OSA
at each SB score from 0-8.
Progressive increase in probability of severe OSA (4.4% to 81.9%) and
progressive decrease in the probability of no OSA (52.5% to 1.1%)
Results: the greater the single cumulative score on the STOPBANG the greater the probability of more severe sleep apnea.
OSA and the Surgical Patient
Screening Tools for OSA
Stratification using the STOP-BANG (Chung, F.)
 STOP-BANG score 0-2
Low risk of OSA
 STOP-BANG score 3-4
Indeterminate risk of OSA
 STOP-BANG score 5-8
High risk of OSA
OSA and the Surgical Patient
Screening Tools for OSA
Validation of the Berlin Questionnaire and American Anesthesiologists Checklist as
Screening Tools for OSA in Surgical Patients.
Chung, F. et al. Anesthesiology V 108 No 5 May 2008, 822-830.
Preoperative pts 18 yrs or older and without previously diagnosed OSA.
2,467 patients were screened using the three screening tools
Performance of the screening tools evaluated in 177 patients that had PSG.
OSA and the Surgical Patient
Screening Tools for OSA
Classified as high risk of OSA
 Berlin Questionnaire
33%
 ASA Checklist
27%
 STOP Questionnaire
28%
No significant difference in the questionnaires in the ability to
identify patients with OSA.
Approximately 30% of general surgical patients will screen
positive for OSA.
OSA and the Surgical Patient
Screening Tools for OSA
Data suggests that the use of screening
questionnaires can reliably identify patients at
risk for obstructive sleep apnea.
 Sensitivity and negative predictive value good. Specificity fair
 False positive rate is 15%-20%.
 Use of any of the screening tools improves the likelihood of identifying
obstructive sleep apnea.
OSA and the Surgical Patient
Screen positive for Obstructive Sleep Apnea.
Now what?
 Evaluate and institute therapy prior to surgery or postoperatively
 Treat at risk patients empirically postoperatively
Use of algorithms to determine “at risk” patients
 Monitor high risk patients perioperatively
Intervene with therapy for cardiopulmonary difficulties.
Evaluation and definitive therapy after discharge.
OSA and the Surgical Patient
Sleep Consultative Service:
 Sleep physician
 Physician extenders
 “Super nurse”
– Antic, N.A. Am J Respir Crit Care Med vol 179. p 501-508, 2009
 Sleep technician/Respiratory therapist/ Sleep navigator
 Template: symptoms, comorbid conditions, physical exam
OSA and the Surgical Patient
Diagnostic testing:
 In lab polysomnography
 Limited channel testing (portable sleep testing)
 Autonomic measures of sleep disordered breathing
– Peripheral arterial tone (PAT)
– Cardiopulmonary coupling (CPC)
Limiting factors
 Time constraints
– Diagnostic study
– Acclimation to PAP
 What to do with patients that refuse study?
OSA and the Surgical Patient
Evaluate and treat patient preoperatively
OSA and the Surgical Patient
Retrospective observational study:
 2 years: 431 patients screened +; 211 PSG (split)
 CPAP offered to moderate/severe OSA.
 Results
– 49% completed the sleep study.
– 138/211 (65%) had moderate to severe OSA
– Median adherence (30 days) 2.5 hours.
– Split night study was completed an average of 4 days prior to surgery.
CPAP Adherence in Patients with Newly Diagnosed
Obstructive Sleep Apnea prior to Elective Surgery.
Gurainick, A. et al. Jr. Clin Sleep Med. Vol 8, No 5,
2012. 501-506. (U of Chicago)
OSA and the Surgical Patient
Treat at risk patients post operatively
OSA and the Surgical Patient
Does Autotitrating Positive Pressure Therapy Improve
Postoperative Outcomes in Patients at Risk for OSAS.
O’Gorman et. al. Chest 144 No 1, July 2013, 72-78.
 138 patients (screened 2,375 pts)
 SACS > 15 high risk
– 52 pts low risk; 86 pts high risk (62%)
– HR pts: 43 pts routine care; 43 pts routine care + APAP.
– Night before D/C. Type III sleep study
 Primary endpoint: Length of stay
 Secondary : ICU transfer, SpO2, cardiopulmonary events
OSA and the Surgical Patient
Results:
 No change in LOS; no difference in rate of postoperative
complications.
 Issues:
– APAP use night 1: 373 mins; median use 184.5 mins.
– Incomplete resolution of sleep apnea
 AHI: 22.2 per hour to 13.5 per hour
 Unable to differentiate obstructive vs central apnea.
 P95%: 9 cm.
OSA and the Surgical Patient
Treat “at risk” patients empirically postoperatively
 Risk stratification algorithms
– Intensity of surgery and type of anesthesia
– Use of postoperative narcotics
– Comorbid conditions
– PACU course*
OSA and the Surgical Patient
Monitor level of sedation
 Richmond Agitation Sedation Scale (RASS)
 Ramsey Sedation Scale
 Pasero Opioid-Induced Sedation Scale (POSS)
– S = Sleeping, easy to arouse
– 1 = Awake and alert
– 2 = Slightly drowsy, easily aroused
– 3 = Frequently drowsy, arousable, drifts off to sleep during conversation *
– 4 = Somnolent, minimal or no response to verbal or physical stimulation *
*requires action
Joint Commission Sentinel Event Alert No. 49 August 8, 2011. Safe
use of opioids in the hospital.
OSA and the Surgical Patient
Post operative management
 Multimodality pain management
– NSAID’s
– Acetominophen
– Tramadol
– Ketamine
– Gabapentin/Pregabalin
– Clonidine
– Dexamethasone
– Dexmedetomidine (Precedex)
 Alpha 2 agonist
 Post operative oxygen desaturation 12-14 times more likely in OSA patients
receiving opioid analgesia compared with non-opioid analgesia.
– Bolden, N. et al. Anesth Analg 2008; 105: 1869-70.
OSA and the Surgical Patient
CoMorbidities: should they be considered in the assessment of
level of monitoring?
 Higher Risk:
– Atrial fibrillation*
– Congestive heart failure*
– Severe COPD
– Coronary artery disease*
– Obesity Hypoventilation Syndrome
– Pulmonary Hypertension Kaw, R. Respiratory Medicine 2011, 105, 619-624.
– Uncontrolled Hypertension*
 Lower Risk:
– Mild COPD
– Hypertension
– Diabetes Mellitus
– Cerebrovascular disease*
– Obesity BMI > 35 kg/m2*
OSA and the Surgical Patient
Obesity Hypoventilation Syndrome
 Meta analysis: prevalence of 19% in pts with OSA
3% in general population
Obesity Hypoventilation Syndrome: an Emerging and Unrecognized Risk Factor Among
Surgical Patients. Kaw et al. AJRCCM 183;2011; A3147
1784 patients both PSG and non cardiac surgery
471 eligible; 269 (57%) OSA
36/269 (13%) had ABG data. 9/36 (3%) criteria for OHS
14/269 (5%) post operative respiratory failure
44% OHS/OSA
3% OSA
OSA and the Surgical Patient
Obesity Hypoventilation Syndrome
 Should include screening for OHS ?
 Screening all patients with OSA/+screen and BMI > 35 with awake ABG not
practical
 Initial screen:
– HCO3 > 27 sens 92% spec 50% for hypercapnea
 Mokhlesi, B. et al. Sleep and Breathing 2007; 11; 117-24.
– Resting wake SpO2 < 93%.
 Piper, A. Sleep Medicine Review 2011; 15; 79-89.
 If both positive: resting wake ABG.
 Consider preoperative sleep consultation.
– Use of APAP inappropriate in these patients (AASM guidelines). Require
titration to determine appropriate PAP therapy.
OSA and the Surgical Patient
Sleep-Disordered Breathing in Hospital Patients:
Identifying and Treating Patients at Risk. Gay, P.
 Use of Sleep Apnea Clinical Score (SACS) to screen
 693 patients non cardiac surgery
 Likelihood of postoperative respiratory events
– High SACS: OR: 3.5
– High SACS and Recurrent events in PACU: OR: 21
 Course in PACU appears to be most predictive of subsequent postoperative
respiratory events.
OSA and the Surgical Patient
PACU experience (Mayo Clinic)
 Initial evaluation period
– 30 minutes after extubation or PACU arrival (whichever is later)
 2nd and 3rd evaluation periods at 30 minute intervals.
 Criteria
– Hypoventilation: < 8 bpm ( 3 episodes for yes)
– Apnea:
>10 secs ( 1 episode for yes)
– Desaturations: SaO2 < 90% (3 episodes for yes)
– Pain-Sedation Mismatch: RSS > 3; VAS > 5
 Positive: 2 or more yes defined as recurrent
OSA and the Surgical Patient
Monitor high risk patients postoperatively
Positive pressure therapy if PACU difficulties
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OSA and the Surgical Patient
Monitoring: What we know
 Most studies show majority of complications occur within the
first 72 hours esp. the first 24 hours.
 Results of study showing increase in AHI maximum 72 hours
postoperative.
 No studies have demonstrated the superiority of one monitoring
strategy or another.
– Oximetry or oximetry / capnography
Monitoring: What we don’t know
 Appropriate duration of monitoring
– Time, presence of narcotics, SpO2
 Appropriate alarm thresholds
 Optimum monitoring strategy
OSA and the Surgical Patient
Recommendations for monitoring
 Use of oximetry in high risk patients
 Continuation of monitoring until able to maintain oxygen saturation > 90% on room
air including a period of sleep (definition of sleep)
 Role of capnography needs to be defined
 Action plan / protocol for response to alarms
 Future: Integrated monitoring systems
OSA and the Surgical Patient
Intolerant/Noncompliant with PAP therapy
 Behavioral therapy
– Elevate Head of bed / Minimize supine position
– Minimize narcotics / sedatives
 O2 with sleep to maintain oxygen saturation > 90%
 Discharge on O2
 Follow up sleep consultation (out-patient)
– Evaluation / Diagnostic testing
– CPAP Clinic
– Desensitization therapy
– Discussion of alternative therapies for OSA
OSA and the Surgical Patient
Law of unintended consequences:
 Monitoring capability / Costs
 Logistics/flow process
 Increased utilization and costs of PAP therapy
 Increased demand for RCP services
 Education
– New technology i.e. capnography
– New terms: AHI, ODI etc
– New skill sets
 False alarms: “alarm fatigue”
 False sense of security
OSA and the Surgical Patient
Discharge recommendations
 Establishment of protocols which ensure that individuals identified at high
risk for OSA are referred for appropriate evaluation, treatment, and
longitudinal care when appropriate.
 Patients discharged on APAP if used during hospitalization.
 Expedited referral for patients in which PAP therapy was initiated during
hospitalization.
OSA and the Surgical Patient
Outcomes Measures
 Postoperative complications
– Cardiopulmonary, neurologic, delerium
 Emergency Care Team calls
 Transfers to higher level of care
 Reintubations
 Length of hospital stay
 Identification and management of OSA
OSA and the Surgical Patient
Things to come?
 Case Western Reserve University
– Dennis Auckley, M.D.
– 311 in-patients admitted to general medicine floor during 4 month
period.
 Assessed both STOP-BANG and Berlin Questionnaire
– 60.2 % positive both screens
– 81.8 % no diagnosis of OSA
– 40.2 % received IV narcotics
– No orders for respiratory monitoring
Sleep Apnea Prevalence in Co-morbid Patients
Drug-Resistant Hypertention
83%
Obesity
77%
Congestive Heart Failure
76%
Type 2 Diabetes
72%*
Pacemakers
59%
Atrial Fibrillation
49%
All Hypertention
Coronary Artery Disease
* Apnea-Hypopnea Index ≥ 5
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37%
30%
Logan et al.
J. Hypertension 2001
Oldenburg et al,
Eur J Heart Failure, 2007
O’Keefe and Patterson.
Obes Surgery 2004
Einhorn et al.
Endocrine Prac 2007
Garrigue et al.
Circulation 2007
Gami et al.
Circulation 2004
Sjostrom et al.
Thorax 2002
Schafer et al.
Cardiology 1999
OSA and the Surgical Patient
Implications for sleep technologists
 Recognition of increased numbers of previously undiagnosed patients
 Higher percentage of these patients will have significant comorbid conditions
which will require in lab testing and titration.
 Opportunities for participation in screening programs and in hospital
consultative services.
OSA and the Surgical Patient
Future Challenges
 Identification of “true” at risk patients
– Higher cutoff for positive questionnaires
– Presence of co-morbid conditions: OHS / pulmonary HTN
 Optimum and prudent monitoring strategy
– Threshold alarms
 Improvement in compliance with therapy during hospitalization
 Process to improve patients evaluation and institution of therapy. (50% rule).
 Expansion of program to other high risk hospitalized medical patients
– In patient sleep consultative services
OSA and the Surgical Patient
Algorithms
 Sleep and Sleep-Disordered Breathing in the Hospitalized Patient. Peter Gay, M.D.
Respiratory Care Sept 2010, Vol 55, No 9, 1240-1254.
 Management of Sleep Apnea in Adults-Functional Algorithm for the Perioperative
Period. Chung, F. M.D. Can J Anesthesia 2010, 57: 849-864.
 Perioperative Management of OSA Patients: Practical Solutions and Care Strategies.
UCSD/University of Toronto.
 Perioperative Management of Obstructive Sleep Apnea. Adesanya, A. et. al. Chest
2010; 138(6) 1489-1498.
 Advoiding Adverse Outcomes in Patients with Obstructive Sleep Apnea (OSA):
Development and Implementation of a Perioperative OSA Protocol. Bolden, N. et. al.
Jr Clin Anesthesia 2009, 21, 286-293.
 An order-based approach to facilitate postoperative decision-making for patients with
sleep apnea. Swart, P. T et. al. Can Jr of Anesthesia. February 16, 2013
QUESTIONS?
wcsherrill@novanthealth.org
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