developing a perioperative obstructive sleep apnea safety program

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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

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 damagePatients with OSA with inadequate monitoring

The Balance of Forces (Malhotra & White, 2002)

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



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


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.


Postoperative factors: Pain management: use of opioids Positioning: supine position Sleep fragmentation with potential REM rebound Comorbid conditions


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?

1998

Obesity Trends* Among U.S. AdultsBRFSS, 1990, 1998, 2007(*BMI 30, or about 30 lbs. overweight for 5’4” person)

2007

1990

No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

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), 492-496. Data from 2000-2005.

BMI > 40 kg/m2 has increased fivefold1:200 adults to 1:33 adults

BMI > 50kg/m2 has increased tenfold1:2,000 adults to 1:200 adults


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



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 patientsPre 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


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)


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) (+) / (-)


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 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


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



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 diagnosisCritical 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



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



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.



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


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


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 STOP-BANG the greater the probability of more severe sleep apnea.



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



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.



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.



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.



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.


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


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?


Evaluate and treat patient preoperatively


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)


Treat at risk patients post operatively


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


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 apneaAHI: 22.2 per hour to 13.5 per hourUnable to differentiate obstructive vs central apnea.P95%: 9 cm.


Treat “at risk” patients empirically postoperatively Risk stratification algorithms

– Intensity of surgery and type of anesthesia– Use of postoperative narcotics– Comorbid conditions– PACU course*


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.


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.


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*


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


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.


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.


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


Monitor high risk patients postoperatively

Positive pressure therapy if PACU difficulties

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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


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


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


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


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.


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


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


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Sjostrom et al.Thorax 2002

Logan et al.J. Hypertension 2001

Oldenburg et al,Eur J Heart Failure, 2007

Einhorn et al.Endocrine Prac 2007

Gami et al.Circulation 2004

Garrigue et al.Circulation 2007

Schafer et al.Cardiology 1999

Sleep Apnea Prevalence in Co-morbid Patients

O’Keefe and Patterson.Obes Surgery 2004

83%

77%

76%

72%*

59%

49%

37%

30%

* Apnea-Hypopnea Index ≥ 5


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.


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


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?

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developing a perioperative obstructive sleep apnea safety program

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