University:
Michigan State University
Course:
MED 617 | Sleep Medicine
Academic year:

2024
Views:

463

Pages:

58
Author:

Hallie Randolph

OSA/OHS Obstructive sleep apnea Obesity hypoventilation syndrome OSA is characterized by repeated upper airway obstruction during sleep causing acute disruptions to blood oxygen levels, heart rate, blood pressure, intrathoracic pressure, and sleep quality. Is it common ? • Recent estimates indicate that from 3% to 23% of women and 9% to 49% of middle-aged men have moderate to severe sleep-disordered breathing as defined by an apnea-hypopnea index (AHI) > 15 events/h. Health effects Risk factors Epworth sleepiness scale STOPBANG STOB BANG questionnaire Sensitivity of stopbang score of 3 or more to detect moderate to severe OSA is 93% and severe OSA is 100%. NPP are 90% and 100% . 0-2: low risk for moderate to severe OSA 5-8 : high risk for moderate to severe OSA 3-4 :Further criteria are required like if BMI is more than 35 then risk increases . 1000 patients Follow up for 12 years Y axis is fatal events Even after adjustment for BMI and others there was 3 fold risk of fatal CVS in untreated severe groups Similar graph for non fatal Diagnosis • Polysymnography .PSG • Home sleep test • Oximetry PSG Polysomnogram (PSG) Warvedaker NV et al. Best Practice of Medicine. Sept. 1999 Scoring respiratory events • Apnea : 90% or more reduction in airflow or complete cessation of air flow for 10 seconds. Oxygen desaturation is not a criteria. • Obstructive apnea: Apnea with evidence of continued respiratory effort i.e, Chest movement persists • Central apnea : Apnea with absent respiratory effort .i.e, No chest movement . • Mixed apnea: if inspiratory effort is absent at the beginning of the event but resumes in the second portion of the event . In-lab PSG Data EEG Data: • Sleep efficiency & latency • Normal 80% efficient • Latency < 30 min, REM latency 60-120 min • Sleep stages & architecture • Normal about 5% stage N1, 50% N2, 20% N3 (slow wave sleep) and 2025% REM • Arousal Index (AI): sleep disruption • Normal AI < 10-25 (large variation by age) • Norms are all age dependent • in general less REM & SWS, more arousals, WASO and lower sleep efficiency as age • EEG abnormalities • Epileptiform activity, alpha intrusion Scoring Criteria: Respiratory Events • Hypopnea definition • ↓ flow ≥ 30% from baseline for at least 10 seconds • 1A. (AASM) with 3% O2 desaturation OR arousal ✓ Requires EEG monitoring • 1B. (CMS) with 4% O2 desaturation ✓ Amenable to portable studies • Respiratory Effort Related Arousal (RERA) • Flattening of inspiratory portion of nasal pressure (or PAP flow) with increasing respiratory effort leading to arousal • No associated desaturation ✓ Requires EEG monitoring Apnea Hypopnea Index ➢AHI = (# apneas + # hypopneas) / sleep hours • AHI < 5: normal • AHI 5 – 15 :mild • AHI 15 –29 :moderate • AHI 30 or above : severe ➢ RDI = (# apneas + # hypopneas + # RERAs) / sleep hours crescendo decrescendo changes in tidal breathing which sandwich central apneas. note that arousals occur at the peak of hyperventilation. This contrasts with the temporal association of arousals occurring at the termination of obstructive apneas Cheyne-Stokes Breathing • There are episodes of ≥3 consecutive central apneas and/or central hypopneas separated by a crescendo and decrescendo change in breathing amplitude . • There are ≥5 central apneas and/or central hypopneas per hour of sleep associated with the crescendo/decrescendo breathing pattern recorded over ≥2 hours of monitoring with a cycle length of ≥40 seconds. Data from JUH sleep lab Home Sleep Study Treatment • Weight loss ,avoid sedatives and alcohol • Stop smoking • CPAP • Surgery • Dental appliances CPAP(continuous positive airway pressure ) • Flow generator with tubing and mask. • Takes air from the room and push it into airways . • It Pushes air out under pressure which keeps airways open and non collapsible . Conclusion: CPAP therapy is associated with reduced all-cause mortality in middle-aged and elderly males, but no significant effect was found in females. All-cause mortality (HR 0.66; 0.59–0.73) and cardiovascular mortality (HR 0.37; 0.16– 0.54) were significantly lower in CPAP-treated than in untreated patients. There were no differences in cardiovascular mortality in CPAP-treated OSA patients vs. normal control subjects (HR 0.82; 0.52–1.29). 27 cohort studies included in the meta-analysis included 3,162,083 participants Compliance • Mask • Humidifier • Ramp • Autotitartion • Bilevel Dental appliances • Proper patient selection Surgery for OSA • Surgery 30-40% effective and lost after years Definition of OHS • Obesity hypoventilation syndrome (OHS) is defined as a combination of obesity (body mass index ⩾30 kg·m−2 AND • daytime hypercapnia (arterial carbon dioxide tension ⩾45 mmHg) occurring in the absence of an alternative neuromuscular, mechanical or metabolic explanation for hypoventilation . Clinical presentations • Acute on top of chronic type 2 respiratory failure . • Referral to respiratory clinic for Suspected OSA Unexplained dyspnea . Pulmonary hypertension They usually have HTN,DM or other comorbidities . • The prevalence of OHS is similar in men and women Nearly 75% were misdiagnosed and treated for obstructive lung disease (most commonly chronic obstructive pulmonary disease) in spite of having no evidence of obstructive physiology on pulmonary function testing Make sure No obstructive lung disease. No Musculoskeletal disease Marik PE, Desai H. Characteristics of patients with the “malignant obesity hypoventilation syndrome” admitted to an ICU. J Intensive Care Med 2013 . OSA and OHS • Approximately 90% of patients with OHS have obstructive sleep apnoea (OSA) defined by an apnoea/hypopnoea index (AHI) ⩾5 events/h). • 70% of patients have concomitant severe OSA (AHI ⩾30 events/h ) • The remaining patients have non-obstructive sleep hypoventilation with no or mild OSA. OHS with sleep hypoventilation • The American Academy of Sleep Medicine (AASM) has arbitrarily defined sleep hypoventilation in adults by the following criteria: • PaCO2 >55 mmHg for >10 min or • An increase in PaCO2 (or surrogate as end-tidal carbon dioxide tension or TcCo2 ) >10 mmHg compared to an awake supine value to a value >50 mmHg for >10 min . TcCo2 Transcutaneous carbon dioxide monitoring Pathophysiology of obesity hypoventilation syndrome (OHS). Obesity-related changes in the respiratory system Central hypoventilation. Obstructive sleep apnoeas and hypoventilation during sleep, mainly during rapid eye movement Criteria for diagnosis • Room air arterial blood gas. Supportive tests for diagnosis : • Elevated serum bicarbonate levels >27 mmol/L….? Early stage . NPPV • And hypoxaemia Management of patients with obesity hypoventilation syndrome (OHS) from diagnosis to integrated care to modify health trajectories. Obesity hypoventilation syndrome (OHS) management strategy.

Obstructive Sleep Apnea Obesity Hypoventilation Syndrome

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