Respiratory muscle strength training (RMST) is becoming widely used as a treatment modality in the field of speech-language pathology (SLP) for patients with impairments in speech, voice, cough, and/or swallowing.
The primary goal of RMST is to increase the force-generating capacity of the inspiratory (inspiratory muscle strength training; IMST) and expiratory muscles (expiratory muscle strength training; EMST). Peer reviewed research documents functional outcomes with RMST including increases in maximum expiratory and inspiratory pressures related to increased respiratory muscle strength, improved voluntary and reflexive cough as measured by peak cough flow, laryngeal compression times, urge to cough and reflex cough strength (Pitts et al., 2009), improved patient self-perception of voice with combined inspiratory and expiratory muscle strength training (Wingate, Brown, Shrivastav, Davenport &Sapienza, 2007) and improved oropharyngeal swallowing outcomes (Park, Oh, Chang & Kim, 2016) reducing risk of pulmonary complications and decreasing dependence on alternate means of nutrition.
While a well known technique introducing RMST into clinical practice can be daunting and overwhelming! This post provides suggestions for where to start, how to evaluate equipment options based on the needs of your case load, discuss candidate selection and provide suggestions for a successful program roll out
Inpatient Rehabilitation and RMST: An ideal pairing
Inpatient rehabilitation settings lend themselves to implementation of intensive treatment modalities given the intensity of the types of service provision. The inpatient unit at NYU Langone Health- Rusk Rehabilitation provides rehabilitation to patients following acquired brain injuries (stroke, TBI, brain tumors), spinal cord injuries, progressive neurological conditions with acute exacerbations and most recently debility from Covid-19. Patients admitted to inpatient rehabilitation require hospital-level care in conjunction with intensive rehabilitation. Our patients are treated 30-60 minutes daily 5-6 days / week allowing for close clinical monitoring and consistent use of RMST to support the recommended 5 day per week protocol, weekly re-assessment for re-calibration of the trainers and access to radiology for objective swallow assessments via modified barium swallows. Depending on clinical presentation, patients may benefit from a RMST plan to improve breath support for communication, and/or improve inspiratory or expiratory muscle strength for communication and swallowing.
How to get started
Work Group
The first step is to identify and engage the clinical team members to form a work group that will dedicate themselves to completing a literature review discussing applicability to a specific unit/setting and a specific patient population, developing a protocol and procedure for RMST use and identifying equipment so that a budgetary plan can occur. The work group will also provide education on RMST via in-services to staff with hands on training with IMST and EMST devices and be responsible for determining staff competency prior to using the devices with patients. In addition, our RMST workgroup will meet with physicians to introduce them to the program, provide them with a review of the literature on safety and efficacy and work collaboratively to help establish guidelines for patient selection. Ultimately these group members become champions to the project roll out and maintenance and complete a retrospective analysis to make adjustments as needed.
Inclusion/exclusion Criteria:
As with any therapy, safety is always first and foremost and must be considered when selecting patients for RMST treatment. At NYU we developed a list of contraindications including developing guidelines to be used when using RMST devices, and expanded those guidelines with the help of our medical team to include other concerns appropriate to our patient population. In addition, we generated a list of considerations specific to our inpatient setting that would warrant verbal discussion with the medical team before initiating RMST use. For example, given the high frequency of trauma patients on our units for diagnoses such as a history of pneumothorax and recent fractures from surgery or trauma were considerations involved in the development of our treatment guidelines.
Additionally, we required that patient assessment needed to demonstrate reduced inspiratory and expiratory pressures that have a direct functional impact on:
- Cough strength / secretion clearance
- Oropharyngeal swallow / airway protection
- Breath support for functional communication
- Vent weaning and /or trach decannulation
In 2009, Evans and Whitelaw published data on normal ranges of maximal respiratory mouth pressures in adults which assists in understanding the baseline function of patients presenting with respiratory weakness. (Evans & Whitelaw, 2009) It is also important to assess your patient’s ability to follow directions and sequence the steps necessary to utilize RMST devices, achieve adequate labial seal around the RMST device and can maintain stable vital signs during inspiratory and expiratory force generating tasks. When unsure of a patients ability to participate in the RMST protocol, we have implemented trials with an incentive spirometer as a “trial run” prior to dispensing a trainer.
Equipment Suggestions:
Selecting equipment appropriate to your population is essential to setting up a successful program. We selected a combination of pressure threshold devices to use for both inspiratory and expiratory muscle strength training and to provide a wide range of pressure threshold settings given that some of our patients are very weak while still allowing for the types of gains they might experience over time in their ability to increase inspiratory and expiratory pressure generation. In addition, some devices on the market can be used as inspiratory and expiratory devices, which should be considered when trying to minimize costs.
The following devices were obtained in the development of our RMST program.
- Manometer- utilized for baseline measures and weekly re-assessment for trainer calibration
- Threshold inspiratory trainer
- Threshold expiratory trainer
- Peak flow meter- used to measure voluntary peak flow rate shown to be a strong correlate to cough strength
We have a combination of trainers through Aspire Respiratory Products and Phillips Respironics to cover the range of needs for our population. We were fortunate to be able to obtain a digital manometer for assessment of maximum inspiratory pressure (MIP) and/or maximum expiratory pressure (MEP). The manometer helps to determine the patient’s baseline function and is used to set the RMST devices for the start of the program. Digital manometers can be cost prohibitive however, and an inability to obtain one should not prevent use of RMST in your therapy regimen. The pressure threshold trainers can be used to identify maximal pressures by gradually increasing the pressure threshold on the device itself incrementally until the patient can no longer pass air through the device. Most digital manometers also require the use of single patient-use mouthpieces and anti-bacterial filters, which will also need to be factored into your budget if you decide to purchase a digital manometer. If you are interested in utilizing a peak cough flow meter, it might be helpful to reach out to your respiratory therapy department to determine if they may already be in your hospital supply.
Outcomes:
We selected the following measures to be taken at these specific time points during the RMST treatment protocol. Each measurement was assessed weekly:
Maximal Inspiratory pressures (MIP)
Maximal Expiratory Pressures (MEP)
Peak Cough Flow (when cough is targeted)
To be assessed on admission and discharge from therapy:
Recommended diet consistencies
Functional Oral Intake Scale (FOIS)
National Outcomes Measurement System (NOMS)
Penetration / Aspiration Scale (when clinically appropriate)
Patient Training and Carryover:
We all know patients can be overwhelmed with information, and carryover outside of therapy sessions can be challenging. We developed patient education handouts and data tracking sheets that have helped support consistency and independent practice
Summary
Roll out of a new program is exciting, but can feel overwhelming at times. We are so grateful for the time and guidance we received throughout this process. Seek out continuing education courses offered by the experts in the field to develop your knowledge base, obtain hands on training, and gain additional tips to guide your program development. If RMST can benefit your patients and improve their outcomes- then stay the course and do not give up!
References
Evans JA & Whitelaw WA, (2009). The assessment of maximal respiratory mouth pressures in adults. Respiratory Care, 54(10): 1348-1359.
Park JS, Oh DH, Chang MY, Kim KM. (2016). Effects of expiratory muscle strength training on oropharyngeal dysphagia in subacutestroke patients: a randomised controlled trial.J Oral Rehabil. May;43(5):364-7.
Pitts T, Bolser D, Rosenbek J, Troche M, Okun MS, Sapienza C.(2009). Impact of expiratory muscle strength training on voluntary cough and swallow function in Parkinson disease.Chest.May;135(5):1301-8.
Wingate JM, Brown WS, Shrivastav R, Davenport P, Sapienza CM. Treatment outcomes for professional voice users. J Voice. 2007 Jul;21(4):433-49. doi: 10.1016/j.jvoice.2006.01.001. Epub 2006 Apr 3. PMID: 16581229.
About the Authors:
Colleen Frayne, MS, CCC-SLP, BCS-S is a Clinical Specialist working on the acute inpatient rehabilitation unit at NYU Health- Rusk Rehabilitation. She obtained her Bachelor of Arts from Loyola College in Baltimore, MD and Masters of Science from MGH Institute of Health Professions. She completed her Clinical Fellowship at Beth Israel Deaconess 
Medical Center in Boston, MA where she remained until transitioning to Rusk rehabilitation in 2013. She obtained Board Certification in Swallowing in 2014 and has a clinical interest in dysphagia, complex medical patients and the use of Respiratory Muscle Strength Training (RMST). Colleen.frayne@nyulangone.org
Liat Rabinowitz, MS, CCC-SLP is Program Manager of Speech Language Pathology at NYU Langone Orthopedic Hospital- Rusk Rehabilitation. She has worked in the field of TBI at both at the acute and sub acute level. She teaches as adjunct instructor at New York University- Steinhardt on neurogenic communication disorders. Her primary areas of interest include aphasia, cognitive disorders Linguistic impairments following TBI and disorders of consciousness. She has presented both at the state and national level on TBI related topics/ adult neurogenic communication disorders. Liat.rabinowitz@nyulangone.org
