Lung Volume Recruitment and MS
Respiratory difficulties are a less common symptom of multiple sclerosis. Problems with breathing may be associated with more advanced disease, however problems can occur at any stage of the disease, even in patients who do not complain of respiratory problems. Just as weakness of leg and hip muscles can affect walking ability, weakness of the respiratory muscles can affect breathing/pulmonary function.
Problems related to breathing in patients with MS can be caused by respiratory muscle weakness, bulbar dysfunction (involving muscles which control speech and swallowing), or abnormalities with breath control. Reduced muscle strength and spasticity can result in lower lung volumes (less air in the lungs) and eventually stiffness of lung tissue and chest wall due to diminished range of motion.
As a musician, the ability to breathe deeply and control my air flow is vital to accomplishing my job. From the beginning stages, band students learn to take in a lot of air and move it forcefully through a narrow instrument to create a beautiful sound. It takes a great deal of effort and power to do so. But outside of performing on an instrument, even musicians may breathe shallowly and fail to utilize their full lung capacity on a regular basis.
In addition to reduced lung volume, MS patients who experience problems with breathing may have a weaker cough which may interfere with clearing the airway. Peak cough flow (PCF) is a common measurement used to assess respiratory muscle weakness. Persons who are unable to clear their airway are at increased risk of pneumonia and respiratory tract infections.
In a recent study, researchers in Canada studied 79 patients with MS who experience pulmonary function abnormalities (i.e. problems related to breathing and lung function) who were referred to a respiratory neuromuscular rehabilitation clinic from February 1999 through December 2010. The goal of the study was to describe the rate of decline of pulmonary function and peak cough flow (PCF) in this select group of MS patients, and to describe the effect of lung volume recruitment (LVR) on pulmonary function in this group.
Patients with neuromuscular diseases such as MS may experience a decrease in a number of measures of pulmonary function. One such measure is the forced vital capacity (FVC) which refers to the total volume of air which can be forcibly exhaled after a person takes in the deepest breath possible. Larger lung capacity can help to improve peak cough flow (PCF) in patients with neuromuscular disease.
Of the 79 patients included in the Canadian study, 35 (44.3%) were seen more than once with a median follow-up of 13.4 months. Patients were significantly disabled with a mean EDSS of 7.33, but no patient was on invasive ventilation during the follow-up period. Fifty patients (67.6%) were on medication for spasticity. Few were on disease-modifying therapy, which included glatiramer acetate and interferon b-1a, and no patient was on chronic corticosteroid therapy.
Overall, 64 patients (82%) had a baseline FVC below normal function (at <80% of predicted volume) and 63 patients (80%) had a baseline PCF insufficient for airway clearance (at <270 L/min [4.5 L/s]). Measurements following lung volume recruitment were obtained in 39 patients with an FVC <80% of predicted and, at their request, in 2 patients with an FVC of 81.4% and 87.6% of predicted respectively.
What is lung volume recruitment?
Lung volume recruitment (LVR) is a technique used to improve PCF by inflating the lungs to their maximal insufflation (inhaling) capacity (MIC) (i.e. taking in as much air as physically possible). Lung volume recruitment, commonly referred to as breath-stacking, may be conducted with a manual resuscitation bag. The patients in this study were instructed to squeeze the bag a sufficient number of times until they felt their lungs were full, repeating the procedure for 5 full lung inflations in each session. Patients were prescribed LVR therapy at least twice daily if it improved pulmonary function in the laboratory.
In reading the study, I was drawn to the idea of lung volume recruitment as it reminded me of a technique I learned in college to help increase my own lung capacity and to stretch the muscles in and around the ribcage. How it is done is by breathing in as much air as you can (do not breathe out yet), raise your arms over your head and breathe in a bit more air (do not breathe out yet), lower your arms, pause, and feel the sensation of your overinflated lungs before slowly breathing out completely. This can be uncomfortable the first few times tried, but with practice you are able to take in more air on command.
In the present study during the follow-up time period, a significant decline in pulmonary function (measured by FVC) and cough (measured by PCF) was observed in this select group of MS/respiratory patients. The good news is, however, that lung volume recruitment was associated with a slower decline in lung function (p<0.0001) and peak cough flow (p = 0.042). Authors suggest that more research is needed.
Perhaps something as simple as practicing deep breathing can help us keep in better physical condition and protect against some types of pulmonary decline. Now before you try to stretch your lungs, please talk to your doctors about what techniques might be best for your specific needs.
Srour N, LeBlanc C, King J, McKim DA (2013) Lung Volume Recruitment in Multiple Sclerosis. PLoS ONE 8(1): e56676. doi:10.1371/journal.pone.0056676
McKim D. Airway Clearance and Lung Volume Recruitment for Neuromuscular Disease (pdf) Ventilator-assisted Living, August 2011, Volume 25, No. 4. Accessed February 3, 2013.
MS Symptoms: Respiration - National MS Society. Accessed February 3, 2013 at http://www.nationalmssociety.org/about-multiple-sclerosis/what-we-know-about-ms/symptoms/respiration/index.aspx
Pulmonary Function Tests - Johns Hopkins Medicine Health Library. Accessed February 3, 2013 at http://www.hopkinsmedicine.org/healthlibrary/test_procedures/pulmonary/pulmonary_function_tests_92,P07759/
Pulmonary Function Testing - Lecture notes, Northern Arizona University. Accessed February 3, 2013 at http://jan.ucc.nau.edu/daa/lecture/pft.htm