Respiratory Muscle Strength Training (RMST)

Respiratory Muscle Strength Training (RMST)

Definition

• RMST is a treatment strategy to strengthen respiratory muscles by increasing their force-generating capacity.

Benefits

• Helps people with:
  • Eustachia
  • Dystonia
  • Dyspnea: Disordered breathing
  • Atypical voice
  • Swallowing issues
  • Distussia: Reduced cough strength
• Benefits instrumentalists, professional voice users, and athletes.

SLP's Role

• Maximize the Swallow Voice Cough (SVC) abilities.
• Results in better voicing and swallowing.

Resistance Based vs. Pressure Threshold Based RMST Devices

Resistance Based

• Targets respiration by adjusting the size of an orifice.
• Increasing/decreasing the size of the hole adjusts resistance.
• Example: The Breather.
• Decreasing the diameter imposes resistance, requiring increased respiratory muscle force.

Pressure Threshold Based

• Calibrated device with a spring-loaded valve.
• Adjustable external dial to control pressure.
• Example: EMST150 by the Aspire company.

RMST Devices

Resistance Based

• The Breather: Targets both inspiration and expiration.
• Power Lung: Not commonly used in the US.
• Power Breathe: Mostly used in the UK.

Breather Details

• Targets COPD, CHF, dysphagia, stroke, hypertension, Parkinson's, and neuromuscular diseases.
• Improves respiratory muscle weakness, dyspnea, quality of life, speech, and swallow performance.
• Invented by Peggy Nicholson in 1980.
• New model ranges from -50 to +55 cm of water pressure.
• High patient compliance due to perceived quality of life improvements.
• Evidence-based results include:
  • Increased MIFIMAT (Maximal Inspiratory Force and Maximal Expiratory Thrust)
  • Improved oxygen saturation
  • Reduced hyperinflation
  • Improved laryngeal function for speech and swallowing
  • Improved delivery and distribution of inhaled medication
  • Faster weaning from mechanical ventilation
  • Shorter length of stay
  • Lowered probability of hospital readmissions

Pressure Threshold Based

• EMST150: Challenges expiratory muscles more than EMST75.
• Uses a spring mechanism to control pressure.
• Turning the cap compresses the spring, increasing the pressure needed to open the valve.
• Functions like a pop-off valve.
• Pressure must be high enough to open the valve during training.

Targeted Muscles

• Abdominal and internal intercostal muscles.
• Submental muscles (crucial for laryngeal elevation and excursion).
• Muscles that move the vocal folds.
• Muscles of the pharynx, larynx, and soft palate.
• Pharynx: For swallowing and eating.
• Larynx: For breathing.

Respiratory Pressures

• Measured in centimeters of water.
• Speech: 5 to 10 cm of water.
• Cough: 100 to 200 cm of water.
• Bowel movement: 200 to 300 cm of water.
• Devices vary from 0 to 150 cm of water.

Inspiratory vs. Expiratory RMST

Inspiratory Targets

• Muscles used for ventilation.
• Vent weaning.
• Tracheostomy.
• Shortness of breath (COPD, emphysema, asthma).
• Increases lung volumes.
• Improves vocal fold opening.

Expiratory Targets

• Swallowing and cough force increase.
• Improves vocal fold closure.
• Improves phlegm and mucus management.
• Improves diaphragmatic weakness.

EMST150 Demonstration

Directions

• Exercise tool to increase the strength of expiratory muscles.
• Perform 5 sets of exercises, 5 days a week for 5 weeks.
• Adjust spring tension by turning the valve:
  • Clockwise: More difficult.
  • Counterclockwise: Easier.
• Use nose clip or hold nose.
• Start with the screw lined up with 30 on the device (least resistance).
• Take a deep breath in, insert the mouthpiece, and make a tight lip seal.
• Blow hard and fast through the mouthpiece.
• If easy, turn the knob clockwise a quarter turn and repeat until you can't move any air through.
• Breathe normally for five minutes to allow muscles to recover.

Protocol Tweaks

• Start where patients can blow air through with a little difficulty (Stacy Castle tweak).
• Ensure adequate rest periods to avoid dizziness.

Training Protocol

• Turn the knob one quarter turn counterclockwise from your choice.
• Train muscles at about 500% of your maximum strength.
• Train five days a week at the initial setting then make adjustments, resting between trials.
• Perform five breath trials with a one-minute break in between.
• Do 5 five-breath trials for a total of 25 breaths per day.

Maintenance Program

• Train three days per week with 25 breaths per session.
• If possible, increase the knob setting to a higher level.
• Never cause extreme breathing effort or fatigue.

Cleaning

• Clean weekly.
• Do not use harmful cleaning agents or ultrasonic cleaning.
• Remove the mouthpiece and wash it with mild soap and warm water.
• Do not put the device in water.

Inspiratory Adapter (IA150)

• Switches from expiratory to inspiratory muscle exercises.
• Used for health conditions, health challenges, and athletic endurance.
• Perform exercises while seated.
• Schedule IA150 and EMST150 training four hours apart if training both inspiratory and expiratory muscles on the same day.
• Training session should take ten to fifteen minutes.

Usage

• Remove the EMST150 mouthpiece and position the EMST150 device into the IA150 adapter.
• To find personal starting point, turn the EMST150 cap clockwise until it stops.
• With the low setting, inhale forcefully using your diaphragm and chest muscles.
• If easy, remove the EMST150 from the adapter and increase the setting by turning the knob one-quarter to one-half turn counterclockwise.
• Continue until you cannot inhale through the device.

Considerations

• Maximum respiratory pressures and voluntary ventilation vary based on sex at birth.
• Treatment should be tailored to patient needs.
• Used for presbyphonia (aging voice), athletic endurance, COPD, emphysema, and COVID.

Paradoxical Vocal Fold Motion

• Neurological compromise where vocal folds close upon inhalation.
• Can be treated with relaxation techniques and RMST.

Spasmodic Dysphonia

• Neurological basis treated with Botox injections.

Conditions Treated with RMST

• COVID
• Sleep apnea
• Cough dysfunction
• Parkinson's disease
• Brainstem stroke
• Cervical spinal cord injury

ALS and Multiple Sclerosis Considerations

• Focus on conserving and compensating energy rather than strengthening.
• Treatment should be patient-specific.

Contraindications

• Pregnancy
• Uncontrolled hypertension (always get doctor clearance).
• Recent head and neck surgery or head and neck cancer.
• GERD
• Hiatal hernias
• Severe secretions
• Recent cardiac or thoracic surgery
• Arrhythmias

IMST with Ventilator and Tracheostomy Patients

• Superior outcomes.
• Use Maggie Chimpetty's protocol.
• Patient must be awake, medically stable, and have decent cognitive status.
• Must tolerate Passy-Muir valve.
• Fraction of inspired oxygen (FiO2) at 50% or less.
• Positive chest x-ray.
• Positive end-expiratory pressure (PEEP) less than 10.
• Co-treatment with respiratory therapy required.

Neuroplasticity

• Retrains neural pathways to perform better.
• Intensity, repetition, overload, and specificity are key.
• Targets voice, swallowing, and cough.
• Focus on transferring training to performance.

Parkinson's Disease Research

• Increase in maximum expiratory pressures related to muscle strength helps with voluntary and reflexive cough.

Subacute Stroke Patients Research

• Reduces pulmonary complications and the need for PEG tubes.
• Patients are PO-fed more quickly with less risk of aspiration.

Voice Users Research

• Patients have a self-perception of improved voice.

Effects of Muscle Strength Training on Video Swallow Studies

• Helps reduce penetration and aspiration.

Resources

• Available resources for starting a respiratory pressure strength program, particularly for outpatient settings, will be shared.