Ventilator Management for Neuromuscular Disease Shahram Amini, MD, FCCM Associate Professor Of Anesthesiology And Critical Care Mashhad University Of Medical Sciences 1

Objectives  Introduction  Historical Perspective  Evaluation of Neuromuscular Patients With Suspected Respiratory Failure  Symptoms and Signs of Respiratory Impairment in Neuromuscular Disease  Evaluation of Respiratory Impairment in Neuromuscular Diseases  Indications for Reimbursement of Noninvasive Ventilation in Neuromuscular Disease  Contraindications to the Use of Noninvasive Ventilation in Neuromuscular Patients  How Soon to Start Noninvasive Ventilation in Neuromuscular Patients  Initiation of NPPV in Neuromuscular Disease  Monitoring and Follow-Up  Indications for Invasive Mechanical Ventilation for Neuromuscular Disease 2

Introduction  Neuromuscular disorders commonly cause respiratory dysfunction, and respiratory failure is the most common cause of death for many of these disorders.  The time course and pattern of dysfunction differ markedly between the various disorders and even between patients with the same disorder 3

Historical Perspective  Poliomyelitis  body ventilators: "iron lungs" or tank ventilators, rocking beds, jacket ventilators  positive pressure ventilators during the 1960s  Noninvasive positive pressure ventilation (NPPV) early 1960s  NNPPV is the preferred ventilator modality for the long- term management of neuromuscular disease patients with respiratory failure (nasal NPPV) 4

Evaluation of Neuromuscular Patients With Suspected Respiratory Failure  Typical History in the past  Referred to pulmonary specialists  An appreciation for the presenting signs and symptoms that indicate incipient respiratory failure.  The frequency of monitoring is determined by the rapidity of progression of the neuromuscular syndrome and may range from every 1 to 2 mos to yearly.  Once the vital capacity drops below 1.2 to 1.5 L (or < 40-50% predicted) or maximal inspiratory pressure below 30% predicted, daytime blood gases should be checked 5

Symptoms and Signs of Respiratory Impairment in Neuromuscular Disease Symptoms Constitutional Generalized fatigue Weakness Cardiopulmonary DyspneaOrthopnea Lower extremity edemaSecretion retention CNS Early morning headachesMood disturbances Daytime hypersomnolencePsychiatric problems Sleep Restless sleepEnuresis NightmaresFrequent arousals Signs Vital Signs TachypneaTachycardia Respiratory Accessory chest and abdomen muscle use Paradoxical breathing pattern Diminished excursion Cardiac Distended neck veinsIncreased P 2 EdemaCyanosis 6

Evaluation of Respiratory Impairment in Neuromuscular Diseases  History and physical examination  Laboratory evaluation  CBC, K +, Ca ++, Mg ++, PO4 -  Spirometry, supine and upright  Peak expiratory flow  Lung volumes  Maximal inspiratory and expiratory pressures  Arterial blood gases  Sleep evaluation  Nocturnal oximetry  Multichannel recording  Full polysomnography  Other  Transdiaphragmatic pressures (in selected patients)  Thyroid function tests  Transcutaneous or end-tidal CO 2 7

Diaphragm weakness or paralysis  May be the sole presenting manifestation of some neuromuscular syndromes.  Orthopnea and abdominal paradox during breathing in the supine position and a > 40% reduction in supine compared to upright vital capacity  Esophageal and gastric pressure monitoring may be needed for confirmation 8

Indications for a Polysomnogram in Neuromuscular Disease  Pressure titration when initiating NPPV  To evaluate for obstructive sleep apnea  Obese, snorer, or hypersomnolence  To seek sleep hypoventilation in Symptomatic patient without daytime hypercapnia or severe pulmonary function defect  Asymptomatic patient with daytime hypercapnia or severe pulmonary function defect 9

Indications for Reimbursement of Noninvasive Ventilation in Neuromuscular Disease Medicare guidelines Optimal nonventilatory therapy of symptoms and Gas exchange abnormalities Daytime hypercapnia (pCO 2 > 45) Nocturnal hypoventilation (O 2 sat 5 consecutive minutes) or FVC < 50% predicted Maximal inspiratory procedure < 60% predicted Other possible indications Repeated hospitalizations for respiratory failure Cor pulmonale 10

Contraindications to the Use of Noninvasive Ventilation in Neuromuscular Patients Relative contraindications Severe swallowing impairment Inadequate family/caregiver support Need for full-time ventilatory assistance Absolute contraindications Upper airway obstruction Uncontrollable secretion retention Inability to cooperate Inability to achieve adequate peak cough flow, even with assistance Inadequate financial resource Inability to fit mask 11

How Soon to Start Noninvasive Ventilation in Neuromuscular Patients  The current consensus view is that noninvasive ventilation should be started after patients have become symptomatic  NPPV should be started after patients have developed nocturnal but before the onset of diurnal hypercapnia so that the development of daytime hypercapnia can be prevented.  Significant daytime hypercapnia (i.e., pCO 2 > 50 mmHg). 12

Methods of Noninvasive Ventilatory Assistance for Neuromuscular Disease  Different masks/interfaces  Several ventilators  A few modes  Diaphragmatic pacer  Assist cough 13

Initiation of NPPV in Neuromuscular Disease  prioritize goals  different locations  selecting a properly fitted, comfortable interface  Starting at low volumes or pressures  Hours of use should also be increased gradually  Daytime to nighttime 14

Possible Goals of Noninvasive Ventilation in Neuromuscular Disease  Alleviate symptoms  Stabilize and/or improve gas exchange  Prevent nocturnal hypoventilation  Improve sleep quality  Enhance quality of life  Reduce complications of respiratory failure (polycythemia, cor pulmonale)  Provide comfort and convenience  Simplify care with optimal portability  Avoid invasive ventilation/tracheostomy  Minimize cost of long-term care and burden on caregivers  Prolong survival 15

Monitoring and Follow-Up  Close attention in early phase  Typical TV ml/kg and PIP CmH2O  Take ABG if NIV is tolerated 4 hours nightly  Check SpO2, PCO2  Day time PCO2 40s -50s is acceptable if symptoms are controlled  Do not use O2  Transient desaturation  sleep apnea  Sustained desaturation  nocturnal hypoventilation 16

Failure to reverse hypoventilation  inadequate inspiratory pressure  excessive air leaking,  too little time using the ventilator. 17

Complications and Adverse Effects of Noninvasive Ventilation Common Air leaking Mask discomfort Claustrophobic reactions Nasal/oral congestion/dryness Eye irritation Gastric insufflation Nasal bridge redness/ulceration Less common Failure to tolerate or ventilate Unusual Aspiration Pneumothorax 18

Indications for Invasive Mechanical Ventilation for Neuromuscular Disease  contraindications for noninvasive ventilation  Intolerant or have failed to experience improvement in gas exchange or symptoms after reasonable attempts with NPPV or body ventilators  Need for full ventilator support  severe bulbar involvement  Discuss the options and place of giving care 19

Management of Invasive Mechanical Ventilation  impair swallowing and impair the patient's capability for airway protection  full-time ventilatory support.  Use tracheostomy  Discuss the options 20

Management of Invasive Mechanical Ventilation  It should be used only as a therapy for acute or chronic respiratory failure if noninvasive approaches have failed and the patient desires aggressive support.  Minimize number of hours per day of ventilator support  Preserve speech and swallowing  Manage cuff  Manage secretions, infection, tracheomalacia, and TE fistula 21

Thanks for your attention  ANY QUESTIONS? 22