Health Professional Info Mouthpiece Ventilation (MPV) What is MPV? MPV is a less intrusive form of noninvasive ventilation that uses a portable home mechanical ventilator (HMV) with a single-limb open-circuit and mouthpiece assembly. The individual receives a ventilator-assisted breath as often as needed by self-initiating an inspiratory effort while placing lips firmly around the mouthpiece. A support arm for the single-limb open-circuit is usually necessary to enable proper positioning of the mouthpiece for ease of access for the user. Who benefits from MPV? Individuals with weak inspiratory and expiratory muscles requiring breathing support during the day may benefit from MPV. Weak inspiratory and expiratory muscles are associated with neuromuscular diseases (e.g., amyotrophic lateral sclerosis, muscular dystrophy, post-polio syndrome), spinal cord injury or muscular skeletal conditions (e.g., kyphoscoliosis). MPV is generally recommended for individuals with adequate oropharyngeal muscle strength and reasonably good range of head motion. The individual must be alert, cooperative and able to communicate. Why would you perform MPV? The ultimate goal of MPV is to provide daytime noninvasive breathing support. MPV may: + Prevent endotracheal tube intubation or tracheostomy thereby reducing the risk of infection; + Facilitate timely endotracheal tube extubation and/or tracheostomy weaning; + Improve an individual s quality of life; and + Promote an individual s independence thereby reducing caregiver burden. Access to MPV enables independent lung volume recruitment (LVR) as the user can sequentially stack ventilator-assisted breaths until maximum insufflation capacity (MIC) is reached. LVR with MPV will: + Improve cough effectiveness and secretion clearance; + Increase mechanical compliance and thoracic range of motion; + Decrease atelectasis; and + Increase speech volume. When do you initiate MPV? MPV should be initiated when diurnal hypercapnea and/or dyspnea is noted despite optimal nocturnal noninvasive ventilation. MPV may also be initiated in the following clinical scenarios: + Post endotracheal tube extubation to minimize the risk of re-intubation; + To facilitate tracheostomy weaning prior to tracheostomy removal (tracheostomy must be capped). This helps the individual to get used to MPV should noninvasive breathing support be required on a long term basis; and Version 1.2 Page 1 of 6
+ Post decannulation with the stoma occluded to minimize risk of tracheostomy re-insertion, especially if daytime breathing support is indicated. Where would you initiate MPV? MPV can be initiated in any clinical or home setting with a medically stable, alert, cooperative individual able to communicate. How do you initiate MPV? MPV is possible with a HMV with existing MPV option and/or most traditional volume-cycled pressure/flowtriggered home ventilators. The set up configuration will differ depending on the type of ventilator available. Bilevel pressure devices and home ventilators in pressure modes are NOT appropriate for MPV. The inspiratory positive airway pressure (IPAP or pressure support) setting limits LVR and cough efficacy; the expiratory positive airway pressure (EPAP or PEEP) generates a constant flow-by which cannot be minimized to 0 cmh 2 O and may be a nuisance to user and; in some instance, the device low EPAP alarm cannot be disengaged, enabling a nuisance alarm during MPV. Clinical Considerations + A learning period may be necessary for individuals who have been ventilated with an artificial airway for an extended period or who have not used LVR with a modified resuscitation bag (e.g., breath-stacking with LVR bag). + The individual needs to generate very little effort via the mouthpiece to initiate a ventilator delivered breath. + With lips placed firmly around the mouthpiece, the individual uses their cheek muscles to draw or sip through the mouthpiece, triggering a ventilator-assisted breath that provides as much air volume as needed. + The individual must be able to close the soft palate, seal the nasopharynx, and open the glottis and vocal cords to allow the ventilator delivered breath to reach the lungs. + Instruct the individual to accept as much air as possible in to the lungs up to the preset pressure limit. Average high pressure limit ranges from 45 to 70 cmh 2 O to allow for MIC. + The individual should feel a satisfying breath volume with every inspiratory effort. The inspiratory volume, flow, time, and rise settings should be adjusted to promote individual comfort. + Exhalation should occur naturally through the nose or open mouth. + A filter proximal to the mouthpiece will soften the ventilator circuit constant flow-by and may improve individual comfort. + A one-way valve proximal to the mouthpiece may be necessary if the individual is unable to exhale through the nose or at the side of the mouth. The one-way valve will alleviate ventilator alarms caused by back-flow (individual exhalation) to the circuit. + Once the individual is familiar with taking ventilator-supported breaths via the mouthpiece, they can start to learn LVR by breath-stacking. This requires taking multiple MPV breaths without exhaling until the lungs are full. LVR with MPV should be followed by gentle exhalation, a breath-hold up to 5 seconds or individual initiated cough effort. + LVR with MPV should not induce dizziness or chest discomfort. + Individual and clinician communication is essential when determining alarm settings to ensure safe, comfortable and effective ventilation. Version 1.2 Page 2 of 6
LVR with MPV is recommended as often as required; with a minimum of 2-3 times per day with 3-5 lung stretches per session. If combined with manually assisted cough (MAC) it is best done before meals and at bedtime to minimize risk of refluxed gastric content. MPV is possible with most home mechanical ventilators (HMV). In the following section we describe the how to set up MPV with the following devices and related accessories: A) HMV with existing MPV option e.g., Trilogy 200; and B) Traditional volume-cycled pressure/flow-triggered HMV with, and without, a proprietary circuit. A) MPV with the Trilogy 200 HMV Parameter settings recommendations for MPV with a volume-cycled pressure/flow-triggered HMV are: Parameter Settings Recommendations Circuit Type Mode Passive Assist / Control MPV ON Tidal Volume (V T ) Set V T larger than spontaneous V T enabling LVR to MIC within 2 to 3 stacked breaths Breath Rate Inspiratory Time Flow Pattern PEEP Low Inspiratory Pressure High Inspiratory Pressure Apnea or Circuit Disconnect Other 0 if the individual has sufficient ventilator-free breathing time (VFBT) or up to 12 if ventilator dependent 1.2 to 1.5 seconds; adjust for comfort and desired peak inspiratory flow (PIF); PIF will be dependent on VT setting Ramp or square as per individual comfort 0 cmh 2 O 1 to 2 cmh 2 O Up to 70 cmh 2 O to allow for LVR to MIC MUST be enabled if the individual has limited VFBT or if close monitoring is required Refer to the clinical manual and software version for further parameters applicable to MPV Version 1.2 Page 3 of 6
B) MPV with a traditional volume-cycled pressure/flow-triggered HMV Minimal requirements for MPV with volume-cycled pressure/flow-triggered HMV include: + Assist / Control mode; + A fixed inspiratory time setting that is not dependent on flow and I:E ratio settings; + Ability to set positive end expiratory pressure (PEEP) low limit capability at 0 cmh 2 O; + Apnea and low breath rate alarms that can be turned OFF; and + Single-limb open-circuit with flow limiting mouthpiece assembly to allow the circuit to remain open to air without triggering the low pressure or apnea alarms. Parameter settings recommendations for MPV with a volume-cycled pressure/flow-triggered HMV are: Parameter Settings Mode Recommendations Assist Control; pressure modes are NOT appropriate for MPV Tidal Volume (V T ) Set V T larger than spontaneous V T enabling LVR to MIC within 2 to 3 stacked breaths Breath Rate Inspiratory Time Rise or Flow Sensitivity PEEP Low Inspiratory Pressure High Inspiratory Pressure Apnea, Circuit Disconnect and/or Low Breath Rate Alarms Other 0 if the individual has sufficient VFBT or up to 12 if ventilator dependent 1.2 to 1.5 seconds; adjust for comfort and desired PIF; PIF will be dependent on VT setting Adjust as per individual comfort Adjust to enable minimal individual effort yet preventing auto-cycling 0 cmh 2 O 1 to 2 cmh 2 O; minimal setting to create sufficient back-pressure against the flow limiting mouthpiece or flow-restrictor Up to 70 cmh 2 O to allow for LVR to MIC MUST be enabled if the individual has limited VFBT or if close monitoring is required; Set the low breath rate alarm one breath above the ventilator set breath rate Refer to the HMV clinical manual and software version for further parameters applicable to MPV Version 1.2 Page 4 of 6
MPV accessories applicable to HMVs are described in the table hereunder followed by a brief item description. MPV Accessories Trilogy 200 HMV Volume-cycle pressure/flow-triggered HMV with a circuit requirement that is: non-proprietary or proprietary Flexible tapered single-limb circuit Use the flexible tapered single-limb circuit in place of the usual HMV nonproprietary circuit; the exhalation valve is not required. Add the flexible tapered single-limb circuit beyond the proprietary circuit Y connector or exhalation valve. Loc-Line modular circuit-support arm with clamp Pressure port connector for pressure line Not required Place the circuit pressure port connector proximal to the mouthpiece for inspiratory trigger sensitivity. It is best to use the existing pressure port within the proprietary circuit assembly. Mouthpiece assembly Flow-restrictor Not required Optional Optional Bacterial filter Version 1.2 Page 5 of 6
Accessories Description + Flexible tapered single-limb circuit; 3-6 feet in length; 22 mm I.D. at the ventilator end and 15 mm I.D. at the user end; this type of circuit performs well when using the Loc-Line modular circuit-support arm, which stabilizes circuit placement and facilitates ease of access to the mouthpiece. + Loc-Line modular circuit-support arm with clamp; to assemble the circuit and support arm, remove the clamp, roll the Loc-Line arm on a flat surface until it is straight, then push the 15 mm I.D. circuit end through the clamp end; keep pushing the circuit until it reaches half an inch beyond the other end of the Loc-Line. The Loc-Line circuit-support arm can be secured to a wheelchair cane, or table top using the clamp. + Mouthpiece assembly appropriate for the individual s needs e.g., adult or pediatric mouthpiece or tapered nipple connector with Tygon tubing, with or without an elbow connector. + Flow-restrictor may be necessary when using the adult mouthpiece as it will allow the ventilator circuit to remain open to air without activating the low pressure or apnea alarm. + Bacterial filter proximal to ventilator or proximal to mouthpiece. How do you monitor LVR-MPV efficacy? Measure and compare spontaneous Forced Vital Capacity (FVC) and peak cough flow (PCF) with and without LVR-MPV. PCF may further improve with a MAC. Glossary EPAP HMV IPAP LVR LVR bag MAC MIC MPV PCF PEEP PIF VRBT V T Expiratory Positive Airway Pressure Home Mechanical Ventilation Inspiratory Positive Airway Pressure Lung Volume Recruitment Lung Volume Recruitment with Resuscitation Bag Manually Assisted Cough Maximum Insufflation Capacity Mouth Piece Ventilation Peak Cough Flow Positive End Expiratory Pressure Peak Inspiratory Flow Ventilator-Free Breathing Time Tidal Volume Version 1.2 Page 6 of 6