1. Perioperative care of OSA Patient
Perioperative care of OSA Patient

2. Case Studies 45 yo male 320 lbs / 5’11”
Rotator cuff repair under general anesthesia
Admitted to ward for overnight pain control

3. Case Studies IV pain medication 3 hours post-op
Repeated 4 hours later when pain prevented sleep

4. 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

5. 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

6. 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.

7. Case Studies
Undiagnosed Obstructive Sleep Apnea Causes Post-operative Death
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, Settlement Date: 7/ Attorney: Howard D. Mishkind
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.

8. Pathophysiology
Repetitive obstruction of upper airways with episodes of cessation of breathing > 10 seconds
Hypopnea/Apnea
Microarousals in an attempt to restore upper airway patency
Text
Adesanya et a

9. OSA Manifestations Snoring Daytime somnolence Morning headaches
Chung et. al

10. Anesthesia and coexisting diseases
Physiologic changes
arterial hypoxemia
arterial hypercarbia
polycythemia
systemic hypertension
pulmonary hypertension
right heart failure
Anesthesia and coexisting diseases

11. Prevalence 2% in women 4% in men
Changing demographics increasing this number
Vastly undiagnosed ( %)
Gross et. al

12. Prevalence - risk factors
Male
Smoking
Diabetes
Treatment-resistant hypertension
Increasing BMI (>35)
Increasing age (>60)
Hypothyroid
Alcoholism
Head and neck cancers
Chung et. al

13. Prevalence surgical patients
No epidemiological studies
Studies used PSG in general surgery patients
Significantly higher
Most cases not diagnosed
Chung et. al

14. OSA frequency in surgical populations
Chung et. al

15. Diagnosis Gold standard is polysomnography in sleep lab
Not feasible to screen everyone
Not practical

16. Sleep study EEG ECG Chin and leg electromyograms Pulse oximetry
Nasal and oral airflow
Chest and abdominal efforts
Gross et. al

17. 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

18. POLYSOMNOGRAPHY

19. Sleep Study Number quantified to generate Apnea Hypopnea Index
Normal - AHI < 5
Mild OSA - AHI
Moderate OSA > 15
Severe OSA > 30

20. 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

21. Treatment
PAP is the mainstay
Short and long term benefits

22. PAP short-term benefits
Improvements in gas exchange
Improved sleep disorder breathing

23. Chau et al.

24. Chau et al.

25. 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

26. Chau et al.

27. Perioperative Care

28. Identifying at-risk patients
Screening questionnaires
too many questions
complicated scoring

29. 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

30. STOP-BANG Sensitivity AHI > 5 = 66% AHI > 15 = 74%

31. STOP-BANG B: BMI > 35 kg/m2 A: Age > 50
N: Neck circumference > 40 cm
G: Male gender

32. STOP-BANG Sensitivity AHI > 5 = 84% AHI > 15 = 93%
Chung et. al

33. 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

34. Increased risk for perioperative complications?
Most studies retrospective, case reports, observational
Varied findings amongst studies
No level one or level two evidence

35. Increased risk for perioperative complications?
higher reintubation rates
hypercapnia
oxygen desaturation
arrhythmias
myocardial injury
delirium
unplanned ICU admission
Chung et al.

36. Perioperative complications
Respiratory complications
Sustained Arrhythmias
Hypertension
More severe OSA = tendency towards more complications

37. Anesthesia and coexisting disease
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

38. Medication effects
Decreased ventilatory response to hypoxia and hypercapnia
Decreased peripheral drive from chemoreceptors/carotid bodies

39. Anesthetic Management

40. Anesthetic effects
“Exacerbates the upper airway anatomic alterations that result in pharyngeal collapse”
Abolish arousal from sleep
REM rebound after anesthesia

41. Practice Guidelines

42. 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

43. 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

44. Scoring OSA risk
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.
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.
C: Requirement for postoperative opioid: None = 0; Low-dose oral opioids = 1; High-dose oral opioids or parenteral or neuraxial opioids = 3.
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.

45. 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

46. Comorbidities Associated with OSA

47. 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

49. Postoperative Management
Analgesia
Oxygenation
Patient positioning
Monitoring

50. Postoperative analgesia
Opiods should be used sparingly
Multi-modal
No background infusions
Caution with concurrent use of sedatives

51. 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

52. Postoperative oxygenation
Aim for baseline
CPAP or NIPPV as soon as feasible

53. 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

54. CPAP in postop period Many questions remain
Duration of CPAP in newly diagnosed patients
Non-compliant patients
Alternative therapies

55. Postoperative positioning
Avoid supine position

56. Postoperative monitoring
Oximetry vs. full monitoring
Continuos vs. intermittent
How long to monitor

57. 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

58. Outpatient v. Inpatient
Sleep Apnea status
Status of coexisting disease
Nature of surgery
Type of anesthesia
Need for post-operative opiods

60. Outpatient???

61. Obesity Hypoventilation Syndrome

62. 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.

63. Obesity Hypoventilation Syndrome
BMI > 30
Daytime awake hypercapnia (PaC02 > 45 mm Hg)
Daytime awake hypoxemia (PaCO2 < 70 mm Hg)

64. 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.

65. Obesity Hypoventilation Syndrome
Pathophysiology
? impaired respiratory mechanics
? leptin resistnace
? impaired compensation to acute hypercapnia
Chaue et al.

66. Obesity Hypoventilation Syndrome
Screening
Presenting patients with high BMI
Serum bicarbonate (compensation of resp. acidosis)
Room air hypoxemia

67. Obesity Hypoventilation Syndrome
Opioid-induced Ventilatory Impairment
central respiratory depression
decreased consciousness
upper airway obstruction

68. 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

70. Typical Malpractice suit
70 % “dead in bed”
Severe OSA
Morbid Obesity
Isolated ward bed
No monitoring
Receiving narctoics
Painful incision
Off O2
Off CPAP
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 .
OSA is a widely prevalent problem and will become an increas- ing preoccupation of anesthesiologists, partly because as knowl-
(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

71. 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
Chung  SA, Yuan  H, Chung  F;  A systemic review of obstructive sleep apnea and its implications for anesthesiologists, Anesth Analg
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
Chau et al. Obesity Hypoventilation syndrome, Anesthesiology
Adesanya et al. Perioperative Management of Obstructive Sleep Apnea, Chest. 2010;138(6):
Chung et. al. Perioperative care of OSA patients. UC San Diego School of Medicine CME. content/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
Medicare National Coverage Determinations Manual: Continuous Positive Airway Pressure (CPAP) 1986
Cheau et al, Obesity Hyperventilation Syndrome. Anesthesiology
Brown  KA, Laferrière  A, Moss  IR;  Recurrent hypoxemia in young children with obstructive sleep apnea is associated with reduced opioid requirement for analgesia, Anesthesiology