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Perioperative care of OSA
Patient
Case Studies
45 yo male
320 lbs / 5’11”
Rotator cuff repair under general anesthesia
Admitted to ward for overnight pain control
Case Studies
IV pain medication 3 hours post-op
Repeated 4 hours later when pain prevented sleep
Case Studies
Two hours later on routine check, nurse found him in full arrest
Internist pre-op history and physical mentions that patient has been
diagnosed with OSA
Case Studies
A 32-year-old male presented for an open reduction and internal fixation of an arm fracture, which was satisfactorily performed under
general anesthesia. He was discharged to the ward on a fentanyl PCA (patient-controlled analgesia) with a 25 mcg bolus, 12-minute
delay, and 25 mcg hourly rate. At night, the nurses heard him snoring loudly. One hour after his last normal vital signs, he was found in
respiratory arrest. He was resuscitated, but displayed signs of anoxic brain damage. By questioning the patient's wife, a consultant was
able to elicit the husband's history of heavy snoring and nocturnal apneic spells that were felt to be clinically consistent with a diagnosis
of sleep apnea
http://www.apsf.org/newsletters/html/2002/summer/04sleepapnea.htm
Case Studies
SETTLED $1,000,000
Medical Malpractice - Young woman suffering from sleep apnea and seizures was not properly monitored in hospital and overmedicated resulting in
respiratory arrest and death.
Sleep apnea patient dies from anoxic brain injury following surgery - $2,000,000 settlement
Several hours after undergoing a laparoscopic cholecystectomy, the patient, a 33 year old man, who suffered from sleep apnea, was found apneic, with his
CPAP not affixed to his face. The patient was unable to be resuscitated and ultimately died. The plaintiff’s allegations included, among other things, failure to
provide proper post surgical care to a sleep apnea patient, failure to adequately monitor the patient, and failure to timely and adequately resuscitate the
patient.
Case was settled for $2 million (with a medical malpractice cap in Virginia of $2 million).
Irv Cantor and Stephanie Grana represented the plaintiff.
Case Studies
Undiagnosed Obstructive Sleep Apnea Causes Post-operative Death
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Hallberg & McClain obtained a $475,000 settlement for a widow when her 46-year-old husband died following kidney surgery. It was alleged that the hospital staff
was negligent in failing to recognize that the patient suffered from obstructive sleep apnea (OSA) and, therefore, failed to provide adequate monitoring and airway
management during the first post-operative day. Expert medical opinion established that the combination of OSA and narcotic pain medication in the immediate
post-operative period exposed the patient to increased risk of airway obstruction leading to cardiopulmonary arrest.
Settlement Amount: $7,000,000.00
Settlement Date: 7/2004
Attorney: Howard D. Mishkind
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Description of Case: Plaintiff, a 45-year-old male, presented to Defendant ABC Hospital for treatment of abdominal pain. During the
postoperative period he exhibited signs and symptoms of sleep apnea with abnormalities in his heart rhythm. Despite his clinical course, John
Doe was transferred from the PACU to an unmonitored medical floor without an EKG monitor, without pulse oximetry monitoring and without
continuous blood pressure monitoring. Less than four hours later he was found in cardiopulmonary arrest. John Doe experienced a
cardiorespiratory arrest that has resulted in anoxic encephalopathy. He is described as being in a persistent vegetative state.
Pathophysiology
Repetitive obstruction of upper
Textairways with episodes of
cessation of breathing > 10 seconds
Hypopnea/Apnea
Microarousals in an attempt to restore upper airway patency
Adesanya et a
OSA Manifestations
Snoring
Daytime somnolence
Morning headaches
Chung et. al
Physiologic changes
arterial hypoxemia
arterial hypercarbia
polycythemia
systemic hypertension
pulmonary hypertension
right heart failure
Anesthesia and coexisting diseases
Prevalence
2% in women
4% in men
Changing demographics increasing this number
Vastly undiagnosed (80 - 90 %)
Gross et. al
Prevalence - risk factors
Male
Smoking
Diabetes
Treatment-resistant hypertension
Increasing BMI (>35)
Increasing age (>60)
Hypothyroid
Alcoholism
Head and neck cancers
Chung et. al
Prevalence surgical patients
No epidemiological studies
Studies used PSG in general surgery patients
Significantly higher
Most cases not diagnosed
Chung et. al
OSA frequency in surgical populations
Chung et. al
Diagnosis
Gold standard is polysomnography in sleep lab
Not feasible to screen everyone
Not practical
Sleep study
EEG
ECG
Chin and leg electromyograms
Pulse oximetry
Nasal and oral airflow
Chest and abdominal efforts
Gross et. al
Sleep Study
For each hour of sleep:
Number of apneas
Number of Hyponeas (>50 drop in flow)
At least 4% drop in O2 saturation for > 10 seconds
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http://s3.amazonaws.com/publicASMBS/GuidelinesStatements/PositionStatement/PERI-OP_MANAGEMENT_OF_OSA-FINAL-EC-APPROVED_3.5.12_forPub.pdf
POLYSOMNOGRAPHY
http://www.thoracic.org/clinical/sleep/sleep-fragment/pages/iatrogenic-artifact-during-polysomnography.php
Sleep Study
Number quantified to generate Apnea Hypopnea Index
Normal - AHI < 5
Mild OSA - AHI 5 - 15
Moderate OSA > 15
Severe OSA > 30
http://s3.amazonaws.com/publicASMBS/GuidelinesStatements/PositionStatement/PERI-OP_MANAGEMENT_OF_OSA-FINAL-EC-APPROVED_3.5.12_forPub.pdf
Sleep Study
United States Centers for Medicare and Medicaid Services
provides coverage for treatment of adult patients with OSA
when the AHI > 15, or when the AHI > 5 and is accompanied
by comorbidities such as excessive daytime sleepiness,
impaired cognition, mood disorders, insomnia, hypertension,
ischemic heart disease, or history of stroke.
Medicare National Coverage Determinations Manual: Continuous Positive Airway Pressure (CPAP) 1986
Treatment
PAP is the mainstay
Short and long term benefits
PAP short-term benefits
Improvements in gas exchange
Improved sleep disorder breathing
Chau et al.
Chau et al.
PAP long-term benefits
Improved gas exchanged
Improved pulmonary mechanics
Central respiratory drive
Improvement in hypertension
Decreased number of apnea-related arrhythmias
? decreased mortality
Chau et. al
Chau et al.
Perioperative Care
Identifying at-risk patients
Screening questionnaires
too many questions
complicated scoring
STOP-BANG
S: Do you snore loudly
T: Do you feel tired during the day
O: Anyone observed you stop breathing during sleep
P: Do you have a history of high blood pressure
STOP-BANG
Sensitivity
AHI > 5 = 66%
AHI > 15 = 74%
AHI > 30 = 79%
STOP-BANG
B: BMI > 35 kg/m2
A: Age > 50
N: Neck circumference > 40 cm
G: Male gender
STOP-BANG
Sensitivity
AHI > 5 = 84%
AHI > 15 = 93%
AHI > 30 = 100%
Chung et. al
STOP-BANG
Validity examined in a study of 177 surgical patients
STOP-BANG and PSG concurrent
AHI > 5 = 66%
AHI > 15 = 74%
AHI > 30 = 80%
Chung et. al
Increased risk for perioperative
complications?
Most studies retrospective, case reports, observational
Varied findings amongst studies
No level one or level two evidence
Increased risk for perioperative
complications?
higher reintubation rates
hypercapnia
oxygen desaturation
arrhythmias
myocardial injury
delirium
unplanned ICU admission
Chung et al.
Perioperative complications
Respiratory complications
Sustained Arrhythmias
Hypertension
More severe OSA = tendency towards more complications
Medication effects
Apnea results from collapse of pharyngeal airway
decrease lumen of airway/collapse = obstruction
Prevented by dilator muscles
This muscle tone is decreased in sleep
Greatly potentiated by anesthetics/sedatives/pain
medications
Anesthesia and coexisting disease
Medication effects
Decreased ventilatory response to hypoxia and hypercapnia
Decreased peripheral drive from chemoreceptors/carotid
bodies
Anesthetic Management
Anesthetic effects
“Exacerbates the upper airway anatomic alterations that result
in pharyngeal collapse”
Abolish arousal from sleep
REM rebound after anesthesia
Practice Guidelines
Practice guidelines for the perioperative
management of patient with OSA
Report by American Society of Anesthesiologists
2006
Not intended as standards or absolute guidelines
Basic recommendations supported by analysis of current
literature and by a synthesis of expert opinion
Goal of reducing adverse outcomes
Practice guidelines for the perioperative
management of patient with OSA
Perioperative risk is a function of
severity of OSA
invasiveness of procedure
requirements for post-procedure analgesic
Scoring OSA risk
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A: Severity of sleep apnea based on sleep study (ie, AHI) or clinical indicators if sleep study not available:
None = 0; Mild OSA = 1; Moderate OSA = 2; Severe OSA = 3. Subtract 1 point in patients using CPAP or
bilevel pressure ventilation preoperatively and postoperatively, and add 1 point in a patient with Paco2 > 50
mm Hg.
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B Invasiveness of surgery and anesthesia: Superficial surgery under local or peripheral nerve block
anesthesia without sedation = 0; Superficial surgery with moderate sedation or general anesthesia or
peripheral surgery under spinal or epidural anesthesia (with no more than moderate sedation) = 1; Peripheral
surgery with general anesthesia or airway surgery with moderate sedation = 2; Major surgery or airway surgery
under general anesthesia = 3.
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C: Requirement for postoperative opioid: None = 0; Low-dose oral opioids = 1; High-dose oral opioids or
parenteral or neuraxial opioids = 3.
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D: Estimation of perioperative risk: Overall score = score of A + greater score of either B or C. Patients with
overall score ≥ 4 may be at increased perioperative risk from OSA. Patients with a score ≥ 5 may be at
significantly increased perioperative risk from OSA.
Practice guidelines for the perioperative
management of patient with OSA
Preoperative Preparation
improve or optimize physical status - CPAP, NIPPV, BiPAP
Inpatient vs. outpatient basis
Identification of possible comorbidities
Comorbidities Associated with OSA
http://anesthesiaandsleep.org/wpcontent/uploads/2011/05/OSA-Web-Final.pdf
Practice guidelines for the perioperative
management of patient with OSA
Intraoperative Management - No randomized studies
anesthetic technique - general, local, nerve block
airway management - deep sedation, ETT
patient monitoring
Postoperative Management
Analgesia
Oxygenation
Patient positioning
Monitoring
Postoperative analgesia
Opiods should be used sparingly
Multi-modal
No background infusions
Caution with concurrent use of sedatives
Opioids and OSA
Brown et found that the total analgesic opiate dose in patients
with OSA and recurrent hypoxemia was half that required in
patients without such a history and attributed this finding to
upregulation of central opioid receptors due to recurrent
hypoxemia
Postoperative oxygenation
Aim for baseline
CPAP or NIPPV as soon as feasible
CPAP in post-op period
Data/Evidence limited
Theoretical benefits
Decreased edema of the upper airway
Decreased tongue size
Increased upper airway volume and stability
Ryan CF, Lowe AA, Li D, Fleetham JA; Magnetic resonance imaging of the upper airway in
obstructive sleep apnea before and after chronic nasal continuous positive airway pressure
therapy, Am Rev Respir Dis 1991 1444 939-944
CPAP in postop period
Many questions remain
Duration of CPAP in newly diagnosed patients
Non-compliant patients
Alternative therapies
Postoperative positioning
Avoid supine position
Postoperative monitoring
Oximetry vs. full monitoring
Continuos vs. intermittent
How long to monitor
Discharge criteria
Oxygenation should return to baseline
No desaturation or deoxygenation while left undisturbed
Monitored for a median of 3 hours longer than non-OSA
Continued for a median of 7 hours after last obstructive
episode
Outpatient v. Inpatient
Sleep Apnea status
Status of coexisting disease
Nature of surgery
Type of anesthesia
Need for post-operative opiods
Outpatient???
Obesity Hypoventilation Syndrome
Obesity Hypoventilation Syndrome
What is it? Separate disease entity?
10-20% of obese OSA patients
8% bariatric patients
High mortality - 46% at 50 months without therapy
Chau et al.
Obesity Hypoventilation Syndrome
BMI > 30
Daytime awake hypercapnia (PaC02 > 45 mm Hg)
Daytime awake hypoxemia (PaCO2 < 70 mm Hg)
Obesity Hypoventilation Syndrome
Severe upper airway obstruction
Restrictive chest physiology
Blunted central respiratory drive
Pulmonary hypertension
Increased risk for comorbidites (CAD, CHF, DM)
Chau et al.
Obesity Hypoventilation Syndrome
Pathophysiology
? impaired respiratory mechanics
? leptin resistnace
? impaired compensation to acute hypercapnia
Chaue et al.
Obesity Hypoventilation Syndrome
Screening
Presenting patients with high BMI
Serum bicarbonate (compensation of resp. acidosis)
Room air hypoxemia
Obesity Hypoventilation Syndrome
Opioid-induced Ventilatory Impairment
central respiratory depression
decreased consciousness
upper airway obstruction
Bottom line
Need to have a system to screen for at risk patients
Need to determine if patient is appropriate for outpatient
Outpatients should be early in day
System in place for perioperative managemet
All players must be involved
Typical Malpractice suit
70 % “dead in bed”
Severe OSA
Morbid Obesity
Isolated ward bed
No monitoring
Receiving narctoics
Painful incision
Off O2
Off CPAP
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The importance of the problem of OSA, both in terms of preva- lence and consequences, is driving changes in the way OSA is investigated worldwide . As primary care physicians have become more adept at identifying the problem clinically,
these resources have been overwhelmed and lengthy waiting lists have resulted . The expense has also caused access problems for some . This has resulted in increased use of simple home based studies to triage the problem . These are suitable
methods to rule in patients with a high pre-test probability on clinical grounds and may prove help- ful to anesthesiologists seeking information quickly in patients presenting for pre-anesthetic assessment .
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OSA is a widely prevalent problem and will become an increas- ing preoccupation of anesthesiologists, partly because as knowl-
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(3) patient in an isolated ward room, (4) has no monitoring, (5) is receiving narcotics, (6) has a painful incision, (7) is off oxygen and (8) is off his or her CPAP device .56
Sources
Ryan CF, Lowe AA, Li D, Fleetham JA; Magnetic resonance imaging of the upper airway in obstructive sleep apnea before and after chronic nasal continuous
positive airway pressure therapy, Am Rev Respir Dis 1991 1444 939-944
Chung SA, Yuan H, Chung F; A systemic review of obstructive sleep apnea and its implications for anesthesiologists, Anesth Analg 2008 1075 15431563
Gross JB, Bachenberg KL, Benumof JL; et al. American Society of Anesthesiologists Task Force on Perioperative Management Practice
guidelines for the perioperative management of patients with obstructive sleep apnea: a report by the American Society of Anesthesiologists Task Force
on Perioperative Management of patients with obstructive sleep apnea, Anesthesiology 2006 1045 1081-1093
Chau et al. Obesity Hypoventilation syndrome, Anesthesiology. 2012. 188-205
Adesanya et al. Perioperative Management of Obstructive Sleep Apnea, Chest. 2010;138(6):1489-1498
Chung et. al. Perioperative care of OSA patients. UC San Diego School of Medicine CME. http://anesthesiaandsleep.org/wpcontent/uploads/2011/05/OSA-Web-Final.pdf
Kushida CA, Littner MR, Morgenthaler T; et al. Practice parameters for the indications for polysomnography and related procedures: an update for
2005, Sleep 2005 284 499-521
Medicare National Coverage Determinations Manual: Continuous Positive Airway Pressure (CPAP) 1986
Cheau et al, Obesity Hyperventilation Syndrome. Anesthesiology 2012 188-205
Brown KA, Laferrière A, Moss IR; Recurrent hypoxemia in young children with obstructive sleep apnea is associated with reduced opioid requirement
for analgesia, Anesthesiology 2004 1004 806-810