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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
  • 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/flow-triggered 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 cmH2O 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 cmH2O 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.

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 Passive
Mode Assist / Control
MPV ON
Tidal Volume (VT) larger than spontaneous VT enabling LVR to MIC within 2 to 3 stacked breaths
Breath Rate 0 if the individual has sufficient ventilator-free breathing time (VFBT) or up to 12 if ventilator dependent
Inspiratory Time 1.2 to 1.5 seconds; adjust for comfort and desired peak inspiratory flow (PIF); PIF will be dependent on VT setting
Flow Pattern Ramp or square as per individual comfort
PEEP 0 cmH2O
Low Inspiratory Pressure 1 to 2 cmH2O
High Inspiratory Pressure Up to 70 cmH2O to allow for LVR to MIC
Apnea or Circuit Disconnect MUST be enabled if the individual has limited VFBT or if close monitoring is required
Other Refer to the clinical manual and software version for further parameters applicable to MPV
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 fixedinspiratory time setting that is notdependent on flow and I:E ratio settings;
  • Ability to set positive end expiratory pressure (PEEP) low limit capability at 0 cmH2O;
  • 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 Recommendations
Mode Assist Control; pressure modes are NOT appropriate for MPV
Tidal Volume (VT) SetVT larger than spontaneous VT enabling LVR to MIC within 2 to 3 stacked breaths
Breath Rate 0 if the individual has sufficient VFBT or up to 12 if ventilator dependent
Inspiratory Time 1.2 to 1.5 seconds; adjust for comfort and desired PIF; PIF will be dependent on VT setting
Rise or Flow Adjust as per individual comfort
Sensitivity Adjust to enable minimal individual effort yet preventing auto-cycling
PEEP 0 cmH2O
Low Inspiratory Pressure 1 to 2 cmH2O; minimal setting to create sufficient back-pressure against the flow limiting mouthpiece or flow-restrictor
High Inspiratory Pressure Up to 70 cmH2O to allow for LVR to MIC
Apnea or Circuit Disconnect 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
Other Refer to the clinical manual and software version for further parameters applicable to MPV
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 proprietary 
Flexible tapered single-limb circuit
Use the flexible tapered single-limb circuit in place of the usual HMV non-proprietary 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 Not required Not required
Bacteria filter

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.
  • Bacteria 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:

Expiratory Positive Airway Pressure

HMV:

Home Mechanical Ventilation

IPAP:

Inspiratory Positive Airway Pressure

LVR:

Lung Volume Recruitment

LVR bag:

Lung Volume Recruitment with resuscitation bag

MAC:

Manually Assisted Cough

MIC:

Maximum Insufflation Capacity

MPV:

Mouth Piece Ventilation

PCF:

Peak Cough Flow

PEEP:

Positive End Expiratory Pressure

PIF:

Peak Inspiratory Flow

VRBT:

Ventilator-Free Breathing Time

VT:

Tidal Volume