Maximal Expiratory Pressures in Spinal Cord Injury Using Two Mouthpieces

doi:10.1378/chest.112.1.113

Chest

Volume 112, Issue 1, July 1997, Pages 113-116

https://doi.org/10.1378/chest.112.1.113 Get rights and content

Study objective

A technique for assessing expiratory muscle strength is the measurement of maximal expiratory pressure (PEmax). Previous studies have shown that a tube-style mouthpiece yields greater PEmax values than a flange-style mouthpiece because the latter technique is limited by the strength of the buccal muscles. In individuals with weak muscles of exhalation, this limitation may not apply because the strength of their buccal muscles may exceed that of the respiratory muscles.

Design

A tube-style mouthpiece and flange-style mouthpiece were used to measure PEmax. The order of the mouthpiece used in testing was alternated between subjects and the greatest values obtained after three efforts were compared.

Setting

Department of Veterans Affairs Medical Center.

Participants

Fifty subjects with chronic spinal cord injury without acute medical illnesses recruited from veterans and the community.

Results

The mean difference between PEmax_tube and PEmax_flange was 20.7 ±26.4 cm H₂O (p=0.0001). Differences were negligible in those with the weakest muscles of exhalation but were substantial even in some quadriplegic subjects.

Conclusion

Even in individuals with neuromuscular disorders, errors in assessment of expiratory strength occur when a flange-style mouthpiece is used, and we recommend that this technique be abandoned in the measurement of PEmax.

Section snippets

Level of Injury

The level and degree of completeness of SCI was determined for each subject by a Rehabilitation Medicine Service physician (C.G.T.). Injury level was determined as follows: (1) incomplete level—the highest level on each side of the body at which there was any loss of motor function; and (2) complete level—the lowest level on each side of the body at which the motor function was graded 3 of 5 or more with a subsequent caudal loss of all motor function. Sensory function was used in the place of

Results

There were 29 individuals with complete SCI and 21 with incomplete SCI. Among those individuals with complete SCI, 8 had cervical, 11 had high thoracic, and 10 had lower injuries. Among those with incomplete SCI, 13 had cervical, 2 had high thoracic, and 6 had lower injuries.

For each level of injury, the difference in PEmax between mouthpieces was greater than zero (Table 1). The mean difference for the entire group was 20.7±26.4 cm H₂O, range was —24 to 110 cm H₂O (p=0.0001). The lower the

Discussion

Owing to the clinical utility of using PEmax to quantify the loss of expiratory muscle strength, it is important to determine correctly the PEmax that a given individual is capable of producing. This study of SCI subjects confirmed prior results found in normal subjects whereby a tube-style mouthpiece yielded higher expiratory pressures than a flange-style mouthpiece.

The best method must accommodate several concerns. In previous studies, patients with generalized neuromuscular disease were

ACKNOWLEDGMENTS

We acknowledge gratefully the advice of David Leith, MD, the advice of Robert Harrington, and the assistance of the Brockton/West Roxbury VAMC Spinal Cord Injury Service in conducting this study.

References (5)

N. Koulouris et al.
Comparison of two different mouthpieces for the measurement of Pimax and Pemax in normal and weak subjects
Eur Respir J
(1988)
C.D. Cook et al.
Static volume-pressure characteristics of the respiratory system during maximal efforts
J Appl Physiol
(1964)

There are more references available in the full text version of this article.

Cited by (24)

Traumatic Spinal Cord Injury: Pulmonary Physiologic Principles and Management
2018, Clinics in Chest Medicine
Citation Excerpt :
For measurement of maximal inspiratory and expiratory pressures (MIP and MEP, respectively), a flange-style mouthpiece is generally used. However, in a study of 50 subjects with tetraplegia, MEP values obtained using a tube-style mouthpiece were significantly greater than those obtained by use of an intraoral flange-style mouthpiece due to perioral air leaks around the latter device.51 Neuromuscular weakness in persons with chronic tetraplegia and high paraplegia is classically associated with spirometric and lung volume measurements demonstrating restrictive ventilatory defects highlighted by reduction in VC, peak expiratory flow, TLC, expiratory reserve volume (ERV) and IC, as well as an increase in residual volume (RV) and little change in FRC.40,52–61
Respiratory muscle training for respiratory deficits in neurodegenerative disorders: A systematic review
2013, Chest
Citation Excerpt :
Depending its style, people are encouraged to maintain a tight seal around the mouthpiece using the buccal muscles.47 Given this, MEP can show improvements after training due to enhancement in buccal muscle performance.47 Although all the studies included in this review described the proper and standardized measurement of MIP/MEP as described by Black and Hyatt48 and the American Thoracic Society guidelines,42 seven7,9,13,27–30 detailed the technical characteristics of the equipment and the procedures used to prevent unnecessary contraction of the buccal muscles and uncontrolled air leaking.
Studies of the impact of respiratory muscle training (RMT) on central neurodegenerative pathologies have been aimed at improving pulmonary function. However, there is no certainty about the effectiveness of RMT in patients affected by these groups of disorders. The purpose of this review was to assess the evidence regarding the efficacy of inspiratory muscle training (IMT) and expiratory muscle training (EMT) on respiratory function in patients with neurodegenerative disorders of the CNS.
A comprehensive search from 1990 to September 2012 on MEDLINE, Physiotherapy Evidence Database (PEDro), PubMed, Cochrane Library, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases was made. Studies reporting on IMT and EMT in patients with neurodegenerative diseases were included. The selected studies were abstracted using a standardized data collection instrument and were assessed by a quality checklist created and adapted from CONSORT (Consolidated Standards for Reporting Trials) and TREND (Transparent Reporting of Evaluation with Nonrandomized Designs).
Twenty-four studies were identified by the search strategy. Only 19 studies met the criteria for full review. Ten studies met all the inclusion criteria and were included in the final analysis. Of the 16 parameters present in the quality assessment checklist, only six were achieved for the studies analyzed.
There is some evidence that RMT improves a number of respiratory function parameters in patients with Parkinson disease and multiple sclerosis; however, the number of studies and their quality are not sufficient to conclude whether IMT or EMT is effective in improving respiratory function in patients with neurodegenerative disorders of the CNS.
Pulmonary function and spinal cord injury
2009, Respiratory Physiology and Neurobiology
Injury to the cervical and upper thoracic spinal cord disrupts function of inspiratory and expiratory muscles, as reflected by reduction in spirometric and lung volume parameters and static mouth pressures. In association, subjects with tetraplegia have decreased chest wall and lung compliance, increased abdominal wall compliance, and rib cage stiffness with paradoxical chest wall movements, all of which contribute to an increase in the work of breathing. Expiratory muscle function is more compromised than inspiratory muscle function among subjects with tetraplegia and high paraplegia, which can result in ineffective cough and propensity to mucus retention and atelectasis. Subjects with tetraplegia also demonstrate heightened vagal activity with reduction in baseline airway caliber, findings attributed to loss of sympathetic innervation to the lungs. Significant increase in airway caliber following inhalation of ipratropium bromide, an anticholinergic agent, suggests that reduction in airway caliber is not due to acquired airway fibrosis stemming from repeated infections or to abnormal hysteresis secondary to chronic inability of subjects to inhale to predicted total lung capacity. Reduced baseline airway caliber possibly explains why subjects with tetraplegia exhibit airway hyperresponsiveness to methacholine and ultrasonically nebulized distilled water. While it has been well demonstrated that bilateral phrenic nerve pacing or stimulation through intramuscular diaphragmatic electrodes improves inspiratory muscle function, it remains unclear if inspiratory muscle training improves pulmonary function. Recent findings suggest that expiratory muscle training, electrical stimulation of expiratory muscles and administration of a long-acting β₂-agonist (salmeterol) improve physiological parameters and cough. It is unknown if baseline bronchoconstriction in tetraplegia contributes to respiratory symptoms, of if the chronic administration of a bronchodilator reduces the work of breathing and/or improves respiratory symptoms. Less is known regarding the benefits of treatment of obstructive sleep apnea, despite evidence indicating that the prevalence of this condition in persons with tetraplegia is far greater than that encountered in able-bodied individuals.
Determinants of Forced Expiratory Volume in 1 Second (FEV<inf>1</inf>), Forced Vital Capacity (FVC), and FEV<inf>1</inf>/FVC in Chronic Spinal Cord Injury
2006, Archives of Physical Medicine and Rehabilitation
Citation Excerpt :
In our study, we used the highest values of FEV1 and FVC from the expiratory efforts. MIP and maximum expiratory pressure (MEP) were reported as the maximum of 3 values, but MEP was not assessed in our analysis because it was measured in fewer participants (n=230).20 Lung volumes were measured by helium dilution.
Jain NB, Brown R, Tun CG, Gagnon D, Garshick E. Determinants of forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC in chronic spinal cord injury.
To assess factors that influence pulmonary function, because respiratory system dysfunction is common in chronic spinal cord injury (SCI).
Cross-sectional cohort study.
Veterans Affairs Boston SCI service and the community.
Between 1994 and 2003, 339 white men with chronic SCI completed a respiratory questionnaire and underwent spirometry.
Not applicable.
Forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC.
Adjusting for SCI level and completeness, FEV₁ (–21.0mL/y; 95% confidence interval [CI], –26.3 to –15.7mL/y) and FVC (–17.2mL/y; 95% CI, –23.7 to –10.8mL/y) declined with age. Lifetime cigarette use was also associated with a decrease in FEV₁ (–3.8mL/pack-year; 95% CI, –6.5 to –1.1mL/pack-year), and persistent wheeze and elevated body mass index were associated with a lower FEV₁/FVC. A greater maximal inspiratory pressure (MIP) was associated with a greater FEV₁ and FVC. FEV₁ significantly decreased with injury duration (–6.1mL/y; 95% CI, –11.7 to –0.6mL/y), with the greatest decrement in the most neurologically impaired. The most neurologically impaired also had a greater FEV₁/FVC, and their FEV₁ and FVC were less affected by age and smoking.
Smoking, persistent wheeze, obesity, and MIP, in addition to SCI level and completeness, were significant determinants of pulmonary function. In SCI, FEV₁, FVC, and FEV₁/FVC may be less sensitive to factors associated with change in airway size and not reliably detect the severity of airflow obstruction.
Dyspnea during daily activities in chronic spinal cord injury
2005, Archives of Physical Medicine and Rehabilitation
Citation Excerpt :
Maximum inspiratory pressures (MIP) and expiratory pressures (MEP) were measured 3 times with either a Validyneb pressure transducer connected to a Hewlett Packard strip chart recorder,c or a Dataq computerized data acquisition systemd with a microchip pressure transducer. Maximal values were reported.7 We used t tests to compare means, and we compared ratios using chi-square tests, using the Fisher exact test when appropriate.
Grandas NF, Jain NB, Denckla JB, Brown R, Tun CG, Gallagher ME, Garshick E. Dyspnea during daily activities in chronic spinal cord injury.
To assess factors associated with breathlessness in chronic spinal cord injury (SCI) during daily activities.
Cross-sectional survey.
Veterans Affairs SCI service and the community.
Four hundred forty-one participants 1 or more years post-SCI, and without acute illness, were recruited between 1994 and 2003 and were categorized according to their ability to walk unassisted, walk with an aid, or to move about by either hand-propelled wheelchair or motorized wheelchair (MWC).
Assessment of injury extent, respiratory symptoms, cigarette smoking, comorbid medical conditions, and spirometry.
Breathlessness during talking, eating, or dressing.
Breathlessness was more common in MWC users (20/85 users, 24%) than in nonusers (20/356, 6%). The main activity associated with breathlessness in 15 MWC users was talking (18%). In MWC users, the risk of breathlessness was related to lifetime cigarette smoking (odds ratio [OR]=1.02; 95% confidence interval [CI], 1.00–1.03 per pack year), and reports of chronic cough (OR=7.8; 95% CI, 2.0–32.7), and wheeze (OR=3.5; 95% CI, 1.04–13.6). SCI level, percentage of predicted forced vital capacity and forced expiratory volume in 1 second, and maximal inspiratory pressures were not related to breathlessness.
Breathlessness during selected daily activities (most commonly talking) was greatest in SCI participants who were most impaired with regard to mobility and was associated with reports of coughing, wheezing, and cigarette smoking.
A longitudinal evaluation of sleep and breathing in the first year after cervical spinal cord injury
2005, Archives of Physical Medicine and Rehabilitation
Citation Excerpt :
A pneumatic pressure gaugee and a hard, oval mouthpiece were used to determine maximal static respiratory pressures. Tubular mouthpieces have been shown to give significantly higher measures of MIP and MEP in both able-bodied23 and spinal injury populations.24 At each testing session, neck circumference was measured at the level of the hyoid bone, and abdomen girth was measured at the level of the umbilicus.
Berlowitz DJ, Brown DJ, Campbell DA, Pierce RJ. A longitudinal evaluation of sleep and breathing in the first year after cervical spinal cord injury. Arch Phys Med Rehabil 2005;86:1193–9.
To establish the incidence of sleep disordered breathing (SDB) after acute tetraplegia and to determine the relation between the Apnea-Hypopnea Index (AHI) score and the previously postulated predictors of SDB in tetraplegia.
Inception cohort. We performed full polysomnography immediately after acute tetraplegia and at 2, 4, 13, 26, and 52 weeks postinjury. Spirometry, maximum inspiratory and expiratory pressures, medication usage, and neck and abdominal girth were also assessed. Preinjury SDB was estimated using the multivariate apnea prediction equation.
Acute care, subacute care, and community.
Consecutive sample with acute tetraplegia. Thirty subjects (25 men) were initially included. Thirteen completed 12 months of follow-up.
Not applicable.
SDB (AHI score >10 events/h) and respiratory function.
Three subjects (10%; 95% confidence interval [CI], 2%–28%) had probable SDB before injury. In the first 48 hours after injury, no subject had SDB. At 2 weeks, 60% (95% CI, 26%–88%) had SDB; at 4 weeks, 62% (95% CI, 38%–82%); at 13 weeks, 83% (95% CI, 61%–95%); at 26 weeks, 68% (95% CI, 44%–88%); and at 52 weeks, 62% (95% CI, 32%–86%). No consistent relation was found between the previously postulated predictors and SDB.
SDB is highly prevalent within 4 weeks of acute tetraplegia.

View all citing articles on Scopus

: Supported by a Department of Veterans Affairs Health Services Research and Development Merit Review Grant.

View full text

Chest

Clinical Investigations: Pulmonary Function Tests: ArticlesMaximal Expiratory Pressures in Spinal Cord Injury Using Two Mouthpieces

Study objective

Design

Setting

Participants

Results

Conclusion

Section snippets

Level of Injury

Results

Discussion

ACKNOWLEDGMENTS

Comparison of two different mouthpieces for the measurement of Pimax and Pemax in normal and weak subjects

Eur Respir J

Static volume-pressure characteristics of the respiratory system during maximal efforts

J Appl Physiol

Clinical Investigations: Pulmonary Function Tests: Articles
Maximal Expiratory Pressures in Spinal Cord Injury Using Two Mouthpieces