Home Mechanical Ventilation Cori Daines, MD Pediatric Pulmonary Medicine

Outline Indications Patients Interfaces Ventilators Modes of ventilation Home considerations Complications Outcomes

Goals Extend the duration of life Enhance the quality of life Reduce morbidity Improve physiologic function Achieve normal growth and development Reduce overall health care costs

Indications Disorders of the respiratory pump Neuromuscular diseases, chest wall diseases, spinal cord injury Obstructive diseases of the airway Craniofacial abnormalities, hypotonia, obesity Parenchymal lung disease BPD, cystic fibrosis Disorders of control of respiration Congenital central hypoventilation syndrome

Indications Inability to wean from mechanical ventilation After and acute illness After prolonged ventilation for a chronic disease Progressive chronic respiratory failure Sleep disturbance Central or obstructive, apnea or hypopnea

Indications/Symptoms Shortness of breath Especially on exertion or lying down Morning headache and insomnia Fatigue and lethargy Increased respiratory rate Restlessness and anxiety

Indications/Criteria Forced vital capacity < 50% predicted Maximal Inspiratory Pressure < 60 ABG pCO2 > 45 Moderate to severe sleep apnea

Patients Cardiopulmonary stability Positive trend in weight gain/maintenance and growth Stamina for play or daily activities while ventilated Freedom from active/recurrent infection, fever, deterioration ATS Position Paper 1990

Interfaces Noninvasive vs. Invasive Age Cognitive ability Body habitus Ventilatory needs Anticipated length of ventilation Family/patient preference

Noninvasive interfaces Nasal masks Full facemasks Nasal pillows Sipper mouthpiece Lipseal/mouthpiece device

NIV: Nasal mask / Prongs Many older patients prefer compared to mouthpiece Problems: Leak, especially mouth Nasal bridge pressure with mask Gum erosion or compression with mask Nasal erosion with prongs Chin strap may be needed

NIV: Full face mask Decreased leak Decreased Cough Talking Eating Increased risk of aspiration Nocturnal use with daytime nasal mask

NIV: Sipper /Lipseal Mouthpiece Daytime use Allows facial freedom Flexed mouthpiece +/- custom orthodontics Intermittently used to augment breathing Continuously used

Complications of NIV Facial and orthodontic changes Aerophagia (PIP > 25 cmH2O) Nasal drying/congestion = humidify Volutrauma - air leak Inadequate ventilation

Tracheostomies Shiley, Bivona, Portex and others Pediatric sizes mimic ETT ID’s Neonatal, pediatric, adult and customized lengths Cuffed and uncuffed Disposable inner cannula models

Tracheostomies

Ventilators

CPAP Continuous Positive Airway Pressure For simple sleep apnea Stents open the airway Decreases work of breathing

BiPAP Pressure Support Ventilation IPAP—the inspiratory positive airway pressure—extra help when breathing in EPAP—the expiratory positive airway pressure--CPAP Cycles based on patient initiated breaths Available with timed back-up rates Used for severe sleep apnea, neuromuscular weakness or insufficiency

Full Ventilation Noninvasive or invasive Pressure cycled or volume cycled SIMV vs. AC Allows pressure support, PEEP, inspiratory time, flow to be added and manipulated

Ventilator Choice Noninvasive vs. invasive Portability Battery life Setting capabilities Reliability Community support

Ventilators Pressure cycled vs Volume cycled Pressure cycled are often triggered by flow sensing reducing work of breathing Flow sensing is also important in pts with high respiratory rates = infants/toddlers

Ventilators Leak can vary with sleep, position, and effort which is problematic with volume cycled ventilators Variable airway resistance and/or pulmonary or chest wall compliance better with volume settings Pressure cycling limits ability to stack

Control vs. SIMV SIMV Modes Control Modes Every breath is supported regardless of “trigger” Can’t wean by decreasing rate Patient may hyperventilate if agitated Patient / vent asynchrony possible and may need sedation +/- paralysis SIMV Modes Vent tries to synchronize with pt’s effort Patient takes “own” breaths in between (+/- PS) Potential increased work of breathing Can have patient / vent asynchrony Control modes are used when complete control over the patient’s ventilation and/or oxygenation is desired. This is usually because the patient’s lung disease is significant enough that you that you wish to give maximal support. Another scenario may be one in which you want to precisely control the PaCO2, as in hyperventilation for increased intracranial pressure. Patients placed on control modes are often deeply sedated and may be given neuromuscular blockers. SIMV modes are chosen when you want the patient to do as much work as they can tolerate and try to minimize the support from the ventilator. SIMV modes are used to wean patients; as you decrease the set rate, the patient will need to do more on their own to maintain normal blood gases. In control modes, if you decrease the rate, the patient’s spontaneous efforts will be fully supported so you will not know how much of that particular tidal volume they are generating on their own. Note that for the paralyzed patient there is no significant difference between assist control and SIMV.

Control vs. SIMV CONTROL MODE SIMV MODE Every breath fully supported Can’t wean by decreasing rate Risk of hyperventilation if agitated SIMV MODE Vent synchronizes to support patient effort Patient takes own breaths between vent breaths Increased work of breathing vs. control

Assist Control Mode Can trigger breaths, but needs support with each breath

SIMV Mode Most patients, improved comfort, stable CO2s

Pressure vs. Volume Pressure Limited Control FiO2 and MAP (oxygenation) Still can influence ventilation somewhat (respiratory rate, PAP) Decelerating flow pattern (lower PIP for same TV) Volume Limited Control minute ventilation Still can influence oxygenation somewhat (FiO2, PEEP, I-time) Square wave flow pattern PRESSURE-LIMITED I would not say that I have limited ability to affect ventilation in PC, though I may choose to increase the PAP recognizing that I accept the potential for increased baro/volutrauma at the same time I also accept that I may suffer a decrease in ventilation with changes in compliance. VOLUME-LIMITED Accept that changes in compliance may lead to increases in peak airway pressures and associated baro/volutrauma.

Pressure vs. Volume Pressure Pitfalls Volume Vitriol tidal volume by change suddenly as patient’s compliance changes this can lead to hypoventilation or overexpansion of the lung if ETT is obstructed acutely, delivered tidal volume will decrease Volume Vitriol no limit per se on PIP (usually vent will have upper pressure limit) square wave(constant) flow pattern results in higher PIP for same tidal volume as compared to Pressure modes Whichever mode one chooses, one needs to be aware of the limitations of that mode. In pressure modes, the tidal volume can drop resulting in hypoventilation or it can increase, leading to overdistention. With volume modes, the peak pressure can increase, resulting in barotrauma if the pulmonary compliance worsens. Regardless of the parameter that is controlled, the other must be monitored as it is a reflection of the compliance and hence the patient’s pulmonary function. Increasing peak pressures on volume mode (or decreasing tidal volumes in pressure modes) can also be a sign that the ETT is obstructed or of another problem with the ventilator circuit.

Pressure vs. Volume Volume No limit on pressure unless set Pressure Square wave pattern results in higher pressure delivered for same volume delivered Pressure Tidal volume changes as patient compliance changes Potential hypoventilation or overexpansion Obstructed trach decreases delivered volume

Pressure vs. Volume Pressure control Set pressure, volume variable Better control of oxygenation than ventilation Better for younger, noncompliant lungs Volume control Set volume, pressure variable Better control of ventilation than oxygenation Better for older more compliant lungs

Need a hand?? Pressure Support “Triggering” vent requires certain amount of work by patient Can decrease work of breathing by providing flow during inspiration for patient triggered breaths Can be given with spontaneous breaths in IMV modes or as stand alone mode without set rate Flow-cycled A patient needs to generate a certain amount of work in order to trigger it. Additionally, a patient has to breathe through an ETT that is almost always narrower than their own airway and ventilate the increased dead space imposed by the vent circuit. A patient may not be able to generate adequate tidal volumes for these reasons. To compensate for this increase in the work of breathing, pressure support is given. The ventilator generates pressure support by adding flow to the circuit during patient-triggered breaths in IMV or SIMV modes. This does not make it easier for the patient to trigger the ventilator but it does help the patient generate larger tidal volumes. Pressure support usually terminates when the flow in the circuit is 25% of the peak flow.

Pressure Support Trigger by patient Provides inspiratory flow during inspiration Given in addition to vent breaths in IMV modes or alone without a set rate, mimicking BiPAP

Bilevel Mode Mimic BiPAP / No Backup Rate

Supporting Equipment External support—PEEP Alarms/Monitoring Pulse oximetry, Apnea monitor, Capnography Humidification External w/ heater, HME Airway clearance Suctioning, Vest, cough assist Talking devices

Discharge Criteria Presence of a stable airway FiO2 less than 40% PCO2 safely maintained Nutritional intake optimal Other medical conditions well controlled Above may vary if palliative care

Discharge Criteria Goals and plans clarified with family and caregivers Family and respite caregivers trained in the ventilation, clearance, prevention, evaluation and all equipment Nursing support arranged for nighttime Equipment lists developed and implemented with re-supply and funding addressed Funding and insurance issues addressed

Continuing Assessment Titration sleep studies Blood gases Bronchoscopy Home monitoring Used more frequently when weaning/decannulating

Complications Ventilator failure Tracheostomy issues Decannulation, blockage, infection Mask-related issues Pressure sores, facial growth issues Under- or over-ventilation

Outcomes Dependent on underlying disease Over 70% 10-year survival, most deaths due to underlying disease In retrospective studies, 0-8% of deaths were ventilator or technology-related Occasional hospitalization

Quality of Life Generally good Some stress for patients, caregivers Fewer hospitalizations Better sleep quality Better daytime functioning Some stress for patients, caregivers Related to amount of care and support needed

Home ventilation reality Every patient is unique These are guidelines not rules Vary settings, interfaces, strategies to achieve goals of good health and optimized quality of life Team approach necessary