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KEEPING YOUR LUNGS HEALTHY: SMA TYPE I. Mary Schroth MD Pediatric Pulmonary American Family Children’s Hospital University of Wisconsin School of Medicine and Public Health. Objectives. Understand how SMA affects breathing Learn techniques to help your child’s breathing
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KEEPING YOUR LUNGS HEALTHY: SMA TYPE I Mary Schroth MDPediatric PulmonaryAmerican Family Children’s HospitalUniversity of Wisconsin School of Medicine and Public Health
Objectives • Understand how SMA affects breathing • Learn techniques to help your child’s breathing • Realize that you have choices in your child’s respiratory care
Encompasses: • Diagnosis • Respiratory Care • GI and Nutrition • Orthopedic Concerns • Palliative Care Wang C et al, J Child Neurol 2007; 22:1027.
Respiratory Function in SMA • Features: • Very weak muscles between the ribs • Chest wall: very soft and flexible during the first year of life • Diaphragm: primary muscle used to breath
Chest Wall Changes Normal SMA
Results of Respiratory Muscle Weakness in SMA • Difficulty coughing • Small shallow breaths during sleep • Chest wall and lung underdevelopment • Recurrent infections that contribute to muscle weakness. Wang C et al, J Child Neurol 2007; 22:1027.
SMA Pulmonary Natural History Natural History Assessment Intervention Physical examination Normal breathing Breathing and swallowing muscle weakness Pulmonary function, peak cough flow, respiratory muscle strength Airway clearance with cough assistance Dream related sleep disordered breathing Weak cough, reduced peak cough flows Chest xray, Sleep study Nocturnal non-invasive ventilation Swallow function evaluation Non-dream and dream sleep disordered breathing Swallow dysfunction Chest infections Nocturnal or continuous non-invasive ventilation Daytime ventilatory failure Death Wang C et al, J Child Neurol 2007; 22:1027.
Assessment and Monitoring of Respiratory Status • Evaluate Cough Effectiveness • Direct observation • Physical Exam • Respiratory rate • Work of breathing • Paradoxical breathing J. Child Neurol 2007; 22:1027.
Assessment and Monitoring of Respiratory Status (cont.) • Chest xray • Swallow study • Polysomnography or sleep study • Scoliosis xrays J. Child Neurol 2007; 22:1027.
Chronic Management • Discussion of family goals • Balancing: • Caring at home for as long as possible • Long term survival • Quality of life and comfort • Resources to support above Wang C et al, J Child Neurol 2007; 22:1027.
Chronic Management Goals • Normalize oxygen saturation and CO2 • Improve sleep • Facilitate care at home • Decrease hospitalizations and PICU stays • Decrease burden of illness on families Wang C et al, J Child Neurol 2007; 22:1027.
Based on Experience and Consensus: • Early aggressive and proactive intervention may prolong life without compromising quality of life. Wang C et al, J Child Neurol 2007; 22:1027.
Chronic Management • Recognizing changes from baseline • Airway clearance • Assisted Cough • Secretion mobilization • Respiratory support • Palliative care Wang C et al, J Child Neurol 2007; 22:1027.
Assisted Cough • Manual cough assist • In-exsufflator cough machine or Cough Assist
Mechanical In-Exsufflation • In-exsufflator cough machine improved cough expiratory flow rates • Mean peak expiratory flow rates of 21 patients with NMD • Unassisted 1.81 ± 1.03 L/sec • Assisted cough 4.27 ± 1.29 L/sec • Exsufflator 7.47 ± 1.02 L/sec • Normal PCF 6-12 L/sec • Critical PCF is 2.7 L/sec Bach J Chest 1993; 104:1553.
Cough Assist Device • SETTINGS to use by mask, mouth piece, tracheostomy tube or endotracheal tube. • INHALE • Start at +30, increase to +40 cm H2O for 1 sec. • EXHALE • Start at –30, increase to -40 cm H2O for 1 sec. • PAUSE TIME • 1-2 sec.
Secretion Mobilization Techniques • Manual Chest Physiotherapy or Mechanical Percussion • Postural Drainage • Use pulse oximetry to guide respiratory therapy. • Do before eating or at least 30 minutes after eating. Wang C et al, J Child Neurol 2007; 22:1027.
Other Techniques Not Proven Vest Airway Clearance Intrapulmonary Percussive Ventilator (IPV)
FRC Relative to Position From Nunn’s Applied Respiratory Physiology, 2000
Pulse Oximetry • Acute decreased oximetry (< 95% while AWAKE) • suggests atelectasis or mucus plugging. • may be the first evidence of respiratory compromise. • < 95% while ASLEEP • suggests hypoventilation or mucus plugging.
Secretion Management • May improve mucociliary clearance • Albuterol nebulized • May thin secretions • Acetylcysteine (Mucomyst™) nebulized • DNase (Pulmozyme™) nebulized
Secretion Management (cont.) • Alter upper airway secretions • Medications • Glycopyrrolate (Robinul) by mouth/G-tube • Scopolamine patch • Steroid nasal spray • Antihistamines/Decongestants by mouth/G-tube • Botox injections of the salivary glands • Surgical Management • Salivary gland resection
Respiratory Support • Non-invasive ventilation • Bilevel positive airway pressure • Mechanical ventilation • Invasive ventilation • Tracheotomy • Palliative care Wang C et al, J Child Neurol 2007; 22:1027.
Non-Invasive Ventilation (NIV) • Short Term Goals • Rest the muscles for breathing • Improve exchange of oxygen for carbon dioxide in the body • Optimize patient comfort • Minimize risk • Avoid intubation Mehta and Hill, AJRCCM 2001; 163:540
Non-Invasive Ventilation (NIV) • Long Term Goals: • Improve sleep • Maximize quality of life • Enhance functional status • Prolong survival Mehta and Hill, AJRCCM 2001; 163:540
Chronic Respiratory Failure:Bilevel Positive Pressure Airway Effects • Sustained reduction of daytime PaCO2 • 3 Theories for NIV effect: • Rests chronically fatigued respiratory muscles • Reverses collapse of small air sacs in the lungs • Alters the CO2 “set point” Mehta and Hill, AJRCCM 2001; 163:540
Indications for NIV • Standard: • Hypoventilation with oxygen saturation <90% and CO2 >45 • Obstructive apnea • Post-operative care
Indications for NIV • Specific to SMA • SMA type I • Oxygen saturation <94% while asleep and or elevated carbon dioxide level during sleep • Needing intubation or BiPAP during a cold • Pneumonia or atelectasis • Chest wall collapse/pectus excavatum • Poor sleep quality
Chest Wall Development After NIV 6 mths 18 mths Courtesy of A. Simonds, Royal Brompton Hospital, UK
NIV Tolerance • 40 children with NMD, 9 months-16yrs • Hypercapnia (n=17), CMV weaning (n=3), nocturnal hypoventilation (n=18), frequent URI with sleep-disordered breathing (n=2) • Results: 38/40 tolerated mask ventilation • PaO2 increased significantly • PaCO2 decreased significantly Simonds AK et al, Eur Respir J, 2000; 16:476.
Respironics Small Child Nasal Mask with Comfort Flap and Head Gear
Respironics Profile Lite Small Child Nasal Mask and Head Gear
Non-Invasive Positive Pressure Ventilation Devices • Bilevel positive airway pressure (BiPAP) 2. Home mechanical ventilator
Bilevel Positive Airway Pressure (BiPAP) Devices • Recommend ST (spontaneous timed) devices • Provides backup respiratory rate • True respiratory muscle rest • Synchronizes with efforts
Bilevel Positive Airway Pressure (BiPAP) ST Devices • Respironics • BiPAP Synchrony – being phased out • BiPAP AVAPS – average volume assured pressure support • Guarantees tidal volume breaths within range of inspiratory pressure • Minimum tidal volume 200 ml • Smallest child approximately 20-25 kg. • BiPAP ST • Trilogy 100
Bilevel Positive Airway Pressure (BiPAP) ST Devices • ResMed • VPAP III ST • Can set breath trigger and cycle sensitivity
Bilevel Positive Airway Pressure (BiPAP) ST Devices • Example settings: • Inspiratory Positive Airway Pressure IPAP (PIP): • 14-20 cm of H20 • Expiratory Positive Airway Pressure EPAP: • 3-6 cm of H20
Bilevel Positive Airway Pressure (BiPAP) • Respiratory rate • Set to capture breathing effort and rest child • Example settings: • <1 year old, RR=30 (highest rate on BiPAP) • 1-3 years old, RR=25 • >3 years old, RR=20-25 • Teenagers to adult, RR=14-16 and recommend sleep study to titrate.
Bilevel Positive Airway Pressure (BiPAP) • Inspiratory time • Time over which the breath is delivered • Example: • Infants and young children 0.5 seconds • Toddlers to child: 0.8 seconds • School age: 1 second • Teen age: 1-1.5 seconds depending on comfort
Bilevel Positive Airway Pressure (BiPAP) • Rise time • Determines how fast the pressure increased to the peak inspiratory pressure • Lower numbers = faster rise time
Home Mechanical Ventilator Examples: LTV (laptop ventilator, LP-6+,LP-10, Newport HT-50 Modes: - Assist control - SIMV (Synchronized intermittent mechanical ventilation) • pressure ventilation • volume ventilation
NIPPV Disadvantages • Gastric distention and vomit especially if children are constipated • Nasal bridge discomfort and other skin irritation • Face changes
NIPPV Challenges • Swallowing difficulty • Excessive secretions • Gastroesophageal Reflux • > 16 hrs/day of ventilation
Invasive Ventilation • Tracheostomy placement • Not an acute intervention • Controversial in non-sitters Wang C et al, J Child Neurol 2007; 22:1027.
Palliative Care • NIV can be used as palliative therapy. • Goals: • Prevent PICU stays and tracheotomy. • Provide symptom relieve • pain, dyspnea, agitation, nausea, anxiety • Provide psychological, social and spiritual support for child and family Wang C et al, J Child Neurol 2007; 22:1027.
The Last Straw for NMD Lung Function • Viral respiratory infections • Result in: • Increased muscle weakness • Increased airway secretions • More difficulty breathing • The answer is not supplemental oxygen!