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Understanding the Impact of Obesity on Breathing and Sleep Scot Jones, BA, RRT-ACCS, RCP

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Is Obesity a Problem? of adults in the United States, or 60 million people, are obese 30% From CDC.gov

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Is Obesity a Problem? Children worldwide are obese 22,000,000 From World Health Organization

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Is Obesity a Problem? From World Health Organization of diabetes of ischemic heart disease certain cancers 58% 21% 8%

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Is Obesity a Problem? of United States medical costs may be directly related to obesity 17% From CDC.gov

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Is Obesity a Problem? Yes.

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A Few Statements Poking fun? I think not. Respect the person, analyze the behavior. Health professionals should have a (basic) understanding of obesitys effects on how we deliver care.

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FACT or FICTION? Obese people tend to be lazier than people who are thinner.

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FACT AND FICTION! Sedentary lifestyle practices do contribute to obesity, but there are many people who are sedentary, but not obese

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FACT or FICTION? Obese people eat too much.

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FACT AND FICTION! Overeating does contribute to obesity, but it is more complicated than just that

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FACT or FICTION? Obese people are less intelligent

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FICTION! Obvious? Maybe not socially!

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FACT or FICTION? Obese people have control over their weight

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FACT AND FICTION! Weight control is very complex. Calories In Calories Out Weight

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Where are we heading? Understanding some terminology Lung Mechanics Comorbidities Obesity Hypoventilation Syndrome Strategies Socioeconomic considerations Critical care considerations Noninvasive, airway, ventilatory, weaning/extubation

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How to Define Obesity

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Methods of Measurement Body Mass Index (BMI) - calculation Hydrostatic weight Body calipers % Body Fat

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Body Mass Index Body Weight (kg) Height (m 2 ) FlawsStrengths Indirect Measurement Doesnt take muscle into account Noninvasive Simple and effective when used in context

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BMI NIH/NHLBI Table BMI < 18.5Below normal weight 19-24Normal weight 25-29Overweight 30-34Class I Obesity 35-39Class II Obesity 40+Class III Obesity National Institutes of Health (NIH), National Heart, Lung, and Blood Institute (NHLBI). The practical guide: identification, evaluation, and treatment of overweight and obesity in adults. Bethesda: National Institutes of Health. 2000, NIH publication 00-4084.

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Lung Mechanics and Obesity

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Diaphragm is pushed upward Weight on chest wall restricts, and prevents diaphragmatic excursion Adipose requires blood/oxygen Increased risk of obstructed upper airway v

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Systemic Proinflammatory State Oversimplified: Proinflammatory molecules lead to a number of metabolic and cardiovascular complications of obesity, which may lead to airway inflammation (think Asthma)

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Related Diseases and Disorders

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Obstructive Sleep Apnea From Washington.edu

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Classifying Severity Apnea Hypopnea Index (AHI) OSA SeverityOSA Score 6-20Mild1 21-40Moderate2 > 41Severe3 Adapted from Gross, JB, Bachenber, KL, and Benumof, JL, et al. Practice guidelines for the perioperative management of patients with obstructive sleep apnea. Anesthesiology 2006; 104:1081.

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OSA Hyper- tension Insulin Resistance Stroke Memory problems Cardiac (HF, Rhythm, MI) Traffic/ Workplace Accidents

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Obesity and OSA 1-SD increase in BMI = 4x increased risk for OSA (Young, et. Al) BMI > 40 = 40-90% prevalence (Rajala, et. Al) 10% change in body weight = 30% change in AHI BMI OSA Prevalence

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Fat Distribution and OSA Male > Female Distribution (central pattern around neck/trunk/abdominal) Schwartz, et al. Annals of the ATS, Feb 2008

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Obesity Hypoventilation Syndrome

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Drive & Strength Respiratory Load Mechanisms of Ventilatory Failure

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Drive & Strength Respiratory Load Mechanisms of Ventilatory Failure Lung and Chest Wall Elastic Loads Lung CL Insp Threshold Chest Wall Mechanics Supine Position Resistive Loads Upper AW Obstruction Lower AW Obstruction Other Loads Increased CO2 Production Increased Deadspace

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Drive & Strength Respiratory Load Mechanisms of Ventilatory Failure Decreased Drive Blunted drive in OHS Resp Depression (Meds) Sleep Deprivation Hypothyroidism CNS disease Decreased Strength Deconditioning and atrophy from acute illness Medications Metabolic Disorders Myopathic Effects

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Apnea/Hypopnea Event PaCO2 pH PaCO2/pH return to baseline OSA

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Apnea/Hypopnea Event PaCO2 pH PaCO2/pH fails to return Renal Compensation HCO3 Depression of Ventilation OHS

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Strategic Considerations

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Meta-Analysis LOS / BMI are directly related statistically > BMI may have a protective effect > LOS may be due to > difficulty in dx and tx, not mobilizing pt as often > LOS = > Mortality (long-term)

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BMI and Disease Risk

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Sociocultural Question #1 As a Health Professional, is it your responsibility to be concerned with a patients weight?

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Sociocultural Question #2 As a Health Professional, is it your responsibility to counsel patients on their weight status (overweight or underweight)

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Sir, Youre Fat.

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A Few Cautions Most people are already aware that they are obese Many people are sensitive about their weight Most people will not (can not?) make major, sweeping changes Consider your own motives and attitudes about people who are obese

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Dilemmas in Diagnostics Diagnostics become increasingly difficult everything: The X-Ray CT Scanning Ultrasound Access for blood-related lab tests Clinical confusion of multiple comorbidities

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The Airway Bergler, et al., 1997

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The Airway

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The Ideal Airway

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Airway Strategies Assess the physiology Proactive use of difficult airway equipment Consider back-up plan what will you do if you cannot intubate? Consider NOT using paralytics or heavy sedation if possible Consider trial of noninvasive ventilation

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Nutrition Actual Body Weight may overestimate (Harris- Benedict Equation) Consider Indirect Calorimetry Consider in context of failure-to-wean

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The Nutrition Balance Caloric Restrictions Catabolic-induced muscle loss impairs wound healing Weakens diaphragmatic muscles delays ventilator weaning Moderate restriction may be okay Excessive Calories Increases production of CO 2 which will increase minute ventilation (tachypnea) -> failed SBT -> potential delays in weaning

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Noninvasive vs. Invasive Treat OSA and OHS Pre-intubation PaO 2 higher with NPPV preparation. Futier, et. Al, Anesthesiology, Vol 114(6), 1354-1363 Post-extubation Support earlier extubation attempts by extubating directly to NPPV

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To Trach or Not to Trach Unable to Wean, repeated intubations, long- term needs CPAP failure with OSA BiPAP failure with OHS (opportunity for ventilatory support at night)

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To Trach or Not to Trach Controlled environment (OR) Trach changes may be a challenge Specialized trachs Early Tracheostomy

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Positioning Consider Reverse Trendelenberg (sitting upward while lying down)

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Early Mobility Laying in a hospital bed quickly results in muscle wasting, and it is much more difficult to get it back once it is gone Early mobilization is a key (yes, even if the patient is in the ICU, and on a vent, and on high FIO2, and on high PEEP) Use of adapted mobility equipment

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Ventilation Strategies What we know: High pressures hurt the lungs Large volumes hurt the lungs There is a greater incidence of later-onset ARDS in patients who are obese than there are in leaner patients (Gong, et al.; Thorax. 2010;65(1):44-50)

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Ventilation Strategies The Big Question: Appropriate V T should be set by: a.) Height b.) Weight c.) Waist circumference d.) Whatever feels right How do we offset, then, the weight on the chest?

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Ventilation Strategies Answer: Using Applied (or therapeutic) PEEP Consider starting point of... +8 to +10 cmH 2 O +15? +20?

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Ventilator Pressures Lung Protective Strategy: Maintain Pplat < 30 cmH2O Obese Patients: There can be a battle between maintaining safe pressures and maintaining adequate ventilation. Consideration: Watch pressures carefully: Consider measuring transpulmonary pressures and maintaining < 35 cmH2O

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Weaning Considerations Adequate Support Provide adequate hemodynamic support Consider tracheostomy with subsequent wean Consider specialized unit and systemized approach Future direction of weaning

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Medication Considerations Pain/Sedation + adipose storage = prolonged period of recovery Significant concern of ventilatory depression with adequate pain management (loss of airway!) Medication administration by IBW, TBW, or DW?

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Obesity is not just a comorbidity. It is a disease.

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Clinical Diagnosis is Complicated So is recovery.

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When the body is BIG The lungs are not