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Adaptive Servo-Ventilation Cases. Geoffrey S Gilmartin, MD Beth Israel Deaconess Medical Center Harvard Medical School Boston, MA. Outline. Case Based Ventilatory Control During NREM Sleep Conceptual framework Specific components Lessons Learned Cases Snapshots Literature
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Adaptive Servo-VentilationCases Geoffrey S Gilmartin, MD Beth Israel Deaconess Medical Center Harvard Medical School Boston, MA
Outline • Case Based • Ventilatory Control During NREM Sleep • Conceptual framework • Specific components • Lessons Learned • Cases • Snapshots • Literature • Conclusions
Case #1 • SH • 37 yo male • Arnold Chiari malformation, spinal stenosis, syringomyelia • Shunt failure in cervical region • Herniation, quadriplegia, PEG and Trach • Snoring converted to witnessed apneas • EDS and extended sleep times
Case #1 • Previous PSG • Failed CPAP/BI-level titration • Residual disease • 624 central and 121 obstructive events • CPAP=7, BI-level=11/7 with RDI-22 • Treated at home and intolerant • Current treatment with O2 2 lpm • Referred for evaluation
Sleep Disordered Breathing • Obstructive Sleep Apnea • CPAP • Cardiovascular, metabolic risk • Central Sleep Apnea • Cheyne-Stokes Respiration • Complex Sleep Apnea • Mixed Sleep Apnea
The System NREM Loss of wakefulness drive Ventilatory Pattern Generator Medulla (pH) Carotid Body (PCO2, PO2) Upper Motor Neuron Lower Motor Neuron Adapted From: Malhotra, Berry and White, “Central Sleep Apnea” Respiratory Muscle/Chest Wall
CSDB-Treatment • Body Position- • Ventilatory Reserves/Obstruction • Sleep Consolidation- • Ventilatory Overshoot/Sleep Wake Instability • Supplemental O2- • Stabilize Chemoreceptors • CPAP/BI-level Pressures- • Plant Gain • Stabilize Ventilation- “Adaptive Ventilation” • Stabilize Plant Gain
Adaptive Servo-Ventilation • Determine Target Ventilation • Monitors recent average minute ventilation (ie.~3 min window) • Calculates a target ventilation (ie. 90% of recent average ventilation) • Ventilates to the Target • Algorithm monitors patient ventilation and compares it to the target ventilation • Adjusts pressure support up or down as needed to achieve target • Back-up rate when needed
End Expiratory Pressure • EEP = CPAP level • Fixed • May adjust to improve upper airway obstruction EEP: manually titrate like CPAP to hold airway patent Pressure (cm H20) Time
maxPS Pressure (cm H20) minPS Time Pressure Support (PS) • Pressure support = (Peak Inspiratory Pressure – End Expiratory Pressure) • Pressure support varies between limits • minPS • maxPS • Can vary the range • Device determines the level
Normal breathing effort Central apnea Pressure (cm H20) Time Response The device “automatically” adjusts the magnitude of pressure support breath by breath to: • Provide minimal support during hyperpnea or stable breathing • Increase support during hypopnea or apnea • Assumption is all is central
Cautions-Hypoventilation • Chronic hypoventilation • Moderate to severe COPD • Chronically elevated PCO2 on ABG (> 45 mm Hg) • Restrictive thoracic or neuromuscular disease
One CSR/CSA cycle, ~1min Central even, no effort Desaturations after Central apneas Baseline Effort Flow SpO2
Support When Needed Effort Flow FG SpO2
Continued Adaptation Effort Flow Response to remaining events FG SpO2
Stability? Effort Flow FG SpO2
2001 • Adaptive Pressure Support Servo-Ventilation • Teschler H, et al. • AJRCCM, 164, 614-19, 2001 • Patients with CHF and CSR (3%, >15/hr) • Acute prospective randomized crossover • 5 sequential nights • N=16
Teschler, et al. • Single night (acute) study • Did randomize order • Covers standard interventions • ASV performs well in this population, in the lab • PCO2 results “reassuring”
Case #2 • RA • 67 yo male • Asthma • OSA-AHI=13, RDI=43, desats to 80% • Failed CPAP/BIPAP Titration-AHI=14.7 • Adapt SV- EEP 5-7, PS 2-10 • Perfection
Recent Data • Adaptive Servoventilation Versus Noninvasive Positive Pressure Ventilation for Central, Mixed And Complex Sleep Apnea Syndromes • Morgenthaler T, et al. • Sleep, 30(4), 2007 • Multicenter, prospective randomized crossover design
Morgenthaler, et al. • DEFINITITIONS • CSA-CSR • CAI >5 events/hr • CAI/AHI >50% • CSR pattern • SA-Mixed • AHI >5 • >50% mixed apneas • Complex SAS • AHI >5 (majority obstructive) • CAI >5 or CSR during titration at best CPAP
Morgenthaler et. al. • Small study • Definitions standard and important • Bi-level alone poor • Exclusion criteria- • CPAP >10 • Hypoventilation • Unstable CHF • Beneficial, ? superior
Case #3 • CH • 83 yo male • CAD-IMI, EF=55%, CRI • OSA-AHI=82.5, Sat Nadir 88% • Failed BIPAP 13/8 with 2 lpm O2 • Concern for central sleep apnea • ASV titration-EEP 5-8, PS-3-10 • Disaster
Long Term • Compliance with and effectiveness of adaptive servo-ventilation versus CPAP in the treatment of Cheyne-Stokes respiration in heart failure over a six month period • Philippe C, et. al. • Heart 92, 337-42, 2006 • Randomized, prospective trial (CSR)