Novel Perioperative Risk Factors:

OSA/Pulmonary Hypertension/OHS:June 30th, 2017

Roop Kaw, MD

Associate Professor of Medicine.

Cleveland Clinic

Objectives

Review postoperative outcomes in patients with

OSA/OHS and PH compared to controls.

Identify patients with OSA who may be higher

risk for postoperative complications

Make the case for screening and perioperative

risk stratification in patients with OSA.

CASE

71 WF admitted to SICU s/p revision of VBG (initial 27 yrs ago) to open

RYGB

Medical morbidities :

Morbid obesity BMI 72. 38; DM; HTN; Ex smoker, COPD on 3 liters O2;

OSA on BiPAP 20/16; PAF on coumadin ; DVT 10 years & PE 2 years

before surgery; s/p IVC filter; Mild to moderate PULMONARY HTN

Positive exertional dyspnea; 4 pillow orthopnea, no PND

Short neck; potential difficult airway; never intubated for COPD

Nuclear perfusion stress test negative for ischemia 10 months ago

Echo 1 month before surgery: Normal sized atria; RV, LV, LVEF 55%

No documented PFTs

ABG one day before surgery: 7.38 / 54 / 95 / 31

Postoperative Course

6 liters O2 for 3 days; then BiPAP (16/6; day 4); SICU for another 2 days;

and discharged in 3 days

Readmitted with acute respiratory failure requiring re-intubation; acute

non-oliguric renal failure and hypotension requiring pressors

Failure to wean from ventilator over next 10 days at which time

tracheostomy was considered

Tracheostomy was done the following day and patient discharged to

LTAC

Dialysis initiated for oliguric acute renal failure

ReaRPostoperative Readmission # 2

Readmitted with hypoxic respiratory failure; unresponsiveness

and hypotension

Antibiotics initiated for presumed septic shock; presumed

source dialysis catheter; pressors started

PEA arrest treated with CPR/ epinephrine; pulse returned

V tach requiring DC shock x 2; epinephrine; pronounced dead

12Memstoudis et al . Anesthesia & Analgesia. 112(1):113-121, January 2011.

Published by International Anesthesia Research Society.2

Prevalence of OSA in General and Orthopedic Surgery patients

Memtsoudis et al…Anesthesia & Analgesia.

112(1):113-121, Jan 2011.

. 2

Respiratory complications in patients w/wo OSA

undergoing Orthopedic (A) or General surgery (B)

14

© The Author [2012]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Date of download: 8/10/2015 Copyright © 2015 American Society of Anesthesiologists. All rights reserved.

Risk of Specific Respiratory and Cardiovascular Complications in Obstructive Sleep Apnea Patients vs. Matched Controls

From: A Matched Cohort Study of Postoperative Outcomes in Obstructive Sleep Apnea:Could Preoperative Diagnosis and

Treatment Prevent Complications?

Anesthesiology. 2014;121(4):707-718. doi:10.1097/ALN.0000000000000407

Percentage of patients hospitalized at least once per year is shown.

Berg G et al. Chest 2001;120:377-383

©2001 by American College of Chest Physicians

Survival curves for patients with OHS (n = 47; mean BMI, 45 kg/m2) vs simple obesity (n = 103; mean BMI, 42 kg/m2).

Mokhlesi B , Tulaimat A Chest 2007;132:1322-1336

©2007 by American College of Chest Physicians

Prevalence of OHS amongst the general adult population in the US can, however

be estimated.

Assuming approximately 3% of the general US population has severe obesity

(BMI ≥ 40 kg/m2).

- half the patients with severe obesity have OSA: 1.5%

- 10-20% of the severely obese patients with OSA have OHS:

1.5-3 per 1000 patients in the general population have OHS.

Recent meta-analysis with the largest cohort of patients (n=4250) reported a 19%

prevalence of OHS among the OSA population, confirming an overall prevalence

of about 3 per 1000.*

Diagnostic criteria for

Obesity Hypoventilation Syndrome

BMI >30 kg/m2

Awake arterial hypercapnia (PaCO2 >45 mm Hg)

Polysomnography reveals OSA in 90% & Sleep hypoventilation in

10% patients.

Rule out other causes of hypoventilation.

Ann Thorac Med. 2009 Apr–Jun; 4(2): 41–49

20

Is it time to Risk Stratify patients

with known or suspected OSA

before surgery?

Which patients with OSA may be considered

high risk for elective surgery?

Patients with Obesity Hypoventilation Syndrome

Patients with severe OSA?

OSA patients with associated Pulmonary Hypertension.

Complex Sleep Apnea among patients on chronic opioid

therapy

Repetitive postoperative hypoxia

OSA severity (A) and PH severity and etiology (B) in

relation to Body Mass Index

For each BMI category in Figure B, bars on the left indicate all patients with PH and bars on

the right indicate patients with “severe” PH (mPAP ≥ 40 mmHg)

Minai OA, Ricaurte B, Kaw R et al. Am J Cardiol; 114: 1300-6

0< 30

20

40

60

80

100

30 -40

Body Mass Index

Re

lative

Fre

qu

en

cy o

f O

SA

(%

)

> 40

5 (16%)

Severe8 (28%)

3 (14%)

12 (37.5%)

Moderate9 (31%)

7 (32%)

15 (47%)Mild

12 (41%)12 (54.5%)

A.

0< 30

20

40

60

80

100

30 -40 > 40

13(41%)

PVH14

(48%)

7(22%)

PAH5

(17%)

13(60%)

6(27%)

7(34%)

mPAP5

(34.5%)6

(27%)Re

lative

Fre

qu

en

cy o

f P

H (

%)

B.Body Mass Index

International Anesthesia Research Society. Published by International Anesthesia Research Society. 2

Figure 2

Perioperative Mortality in Patients with Pulmonary Hypertension Undergoing Major Joint Replacement.Memtsoudis, Stavros; MD, PhD; Ma, Yan; Chiu, Ya; Walz, J; Voswinckel, Robert; Mazumdar, Madhu

Anesthesia & Analgesia. 111(5):1110-1116, November 2010.DOI: 10.1213/ANE.0b013e3181f43149

Figure 2 . The incidence of adverse events for full and matched samples. PHTN = pulmonary hypertension; THA = total hip arthroplasty; TKA = total knee arthroplasty.

IMPACT* Registry

n = 60,000

CCF RHC** Registry

n = 5445

Patients who underwent both

Non-Cardiac Surgery (NCS) and

Right Heart Catheterization (RHC)

n = 526

I/E Criteria (list)#

n = 173

Patients with PH

who underwent NCS

(n = 96)

Patients without PH

who underwent NCS

(n = 77)

Flow Diagram of Patient Selection for the Study

*IMPACT: Internal Medicine Preoperative Assessment, Consultation and Treatment. †RHC: Right Heart

Catheterization. ‡Age<18 yrs; Cardiac Surgery prior to NCS; minor procedures under local anesthesia and / sedation.

Perioperative Outcomes in Patients with & without

Pulmonary Hypertension After Non-cardiac Surgery

Perioperative Outcome PH No PH p-Value OR

(n = 96) (n = 77)

Morbidity/Mortality* 26.0 2.6 <.0001 13.1

Perioperative MI 1.0 0.0 .28

Perioperative CHF 13.5 1.3 .001 11.9

Hemodynamic Instability 8.3 0.0 .002 -

Sepsis 10.4 0.0 .0005 -

Respiratory Failure 7.3 0.0 .004 -

Prolonged Intubation 8.3 0.0 .002 -

ICU Length of Stay (Days) .66 ±2.7 .01 ± .11 .04 -

Hospital Length of Stay (Days) 7.0 ± 9.3 3.2 ± 3.1 .0008 -

30 day Hospital Readmission 16.7 7.8 .08 2.4

MI= Myocardial Infarction; CHF= Congestive Heart Failure; ICU: Intensive Care Unit.

* Numbers represent percentages within each group unless otherwise noted.

Date of download: 8/25/2014

Copyright © American College of Chest Physicians. All rights reserved.

From: Perioperative Risk and Management in Patients With Pulmonary HypertensionPulmonary Hypertension

and Surgery

Chest. 2013;144(1):329-340. doi:10.1378/chest.12-1752

Most Important things to avoid in the Perioperative setting

Spinal anesthesia is contraindicated among PH

patients due to its profound sympatholytic effects

and rapid onset.

Caution is advised with iv narcotics to prevent or

reverse sympathetically mediated increase in PVR.

Abrupt weaning from pulmonary vasodilators can

prevent dangerous rebound in PH.

Hyperinflation of lungs should be avoided because

PVR is lowest at lung volumes at or near FRC.

Among other things it reduces LV preload.

Identifying RV Failure

Life threatening rebound PH may occur in patients being weaned from

pulmonary vasodilators especially inhaled nitric oxide or mechanical

ventilation.

Elevations in RA pressure and reductions in CO are of much greater

concern than elevations in PA pressure as this indicates RV FAILURE.

Presence of significant RV dysfunction should prompt re-evaluation of

the need for surgery.

For patients with RV failure any surgeries beyond minor should be

avoided.

Society of Anesthesia and Sleep Medicine

Annual Meeting

Oct 20-21, 2016Chicago

http://www.sasmhq.org

Conclusions

OSA is a newly recognized perioperative risk factor and increases

the risk for postoperative complications.

OHS poses a much higher risk for postoperative complications

especially respiratory failure & must be screened for before NCS.

Patients with PH (known or unrecognized) are at risk of death

after NCS.

Right Ventricular failure & Respiratory failure are the most

common postoperative complications in patients with PH.