Determinants of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC in chronic spinal cord injury

Long-Term Pulmonary Function Postspinal Cord Injury

OBJECTIVE

To investigate mean values of pulmonary function tests (PFT) at specific time points to assess long-term progression in patients with spinal cord injury (SCI).

DESIGN

Retrospective cohort study from 1997-2022.

SETTING

National rehabilitation hospital, providing scheduled admission for potential SCI-related issues. Follow-up assessments are recommended annually, guiding the observation period into consecutive 1-year intervals.

PARTICIPANTS

This study included 1394 adult patients who were admitted at least twice to the National Rehabilitation Center between 1997 and 2022, selected from an initial pool of 1510. Overall, 116 patients were excluded owing to the absence of any PFT results.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Changes in PFT values over time, specifically assessing for a potential 2-phase pattern after injury. The hypothesis that PFT values would initially improve before declining was formulated based on existing literature.

RESULTS

Significant changes in pulmonary function were noted among 1394 adults with SCI. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) initially increased within the first 1-2 years after injury but declined to below baseline levels after 6 years. Pronounced changes occurred between <1 year and 1-2 years after injury (FVC: Δ=4.89, SE=0.87, P<.001; FEV1: Δ=4.28, SE=1.09, P=.002) and 1-2 years to >6 years (FVC: Δ= -5.83, SE=0.94, P<.001; FEV1: Δ= -6.49, SE=1.18, P<.001). No significant changes in the FEV1/FVC ratio. Motor completeness was significantly associated with the increase and decline phase, showing a steeper increase and less decline compared with the motor-incomplete group.

CONCLUSIONS

Pulmonary function in SCI initially increases but declines over time, falling below initial levels by 6 years. Further evaluation with more complete datasets is warranted to elucidate the factors influencing these changes.

Changes in respiratory structure and function after traumatic cervical spinal cord injury: observations from spinal cord and brain

Respiratory difficulties and mortality following severe cervical spinal cord injury (CSCI) result primarily from malfunctions of respiratory pathways and the paralyzed diaphragm. Nonetheless, individuals with CSCI can experience partial recovery of respiratory function through respiratory neuroplasticity. For decades, researchers have revealed the potential mechanism of respiratory nerve plasticity after CSCI, and have made progress in tissue healing and functional recovery. While most existing studies on respiratory plasticity after spinal cord injuries have focused on the cervical spinal cord, there is a paucity of research on respiratory-related brain structures following such injuries. Given the interconnectedness of the spinal cord and the brain, traumatic changes to the former can also impact the latter. Consequently, are there other potential therapeutic targets to consider? This review introduces the anatomy and physiology of typical respiratory centers, explores alterations in respiratory function following spinal cord injuries, and delves into the structural foundations of modified respiratory function in patients with CSCI. Additionally, we propose that magnetic resonance neuroimaging holds promise in the study of respiratory function post-CSCI. By studying respiratory plasticity in the brain and spinal cord after CSCI, we hope to guide future clinical work.

Efficacy of Wheelchair Skills Training Program in Enhancing Sitting Balance and Pulmonary Function in Chronic Tetraplegic Patients: A Randomized Controlled Study

Background and Objectives: This study aimed to evaluate the effectiveness of a wheelchair skills training program (WSTP) in improving sitting balance and pulmonary function in patients with chronic tetraplegia resulting from cervical spinal cord injury (cSCI). Materials and Methods: Twenty-four patients were randomly divided into WSTP and control groups. The WSTP group participated in the WSTP for eight weeks, while the control group underwent conventional physical therapy for the same eight-week period. Sitting balance was evaluated using the activity-based balance level evaluation (ABLE) scale, and pulmonary function was evaluated using forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow (PEF). Results: The WSTP group showed significant improvements in both sitting balance and pulmonary function during the intervention period (p < 0.05), whereas the control group did not show any significant changes. A strong positive correlation was found between ABLE scores and all three pulmonary function parameters across all time points. Conclusions: Our results suggest that the WSTP significantly improves sitting balance and specific aspects of lung function in patients with tetraplegia.

Systemic and Pulmonary Inflammation/Oxidative Damage: Implications of General and Respiratory Muscle Training in Chronic Spinal-Cord-Injured Patients

Chronic spinal cord injury affects several respiratory-function-related parameters, such as a decrease in respiratory volumes associated with weakness and a tendency to fibrosis of the perithoracic muscles, a predominance of vagal over sympathetic action inducing airway obstructions, and a difficulty in mobilizing secretions. Altogether, these changes result in both restrictive and obstructive patterns. Moreover, low pulmonary ventilation and reduced cardiovascular system functionality (low venous return and right stroke volume) will hinder adequate alveolar recruitment and low O₂ diffusion, leading to a drop in peak physical performance. In addition to the functional effects described above, systemic and localized effects on this organ chronically increase oxidative damage and tissue inflammation. This narrative review describes both the deleterious effects of chronic spinal cord injury on the functional effects of the respiratory system as well as the role of oxidative damage/inflammation in this clinical context. In addition, the evidence for the effect of general and respiratory muscular training on the skeletal muscle as a possible preventive and treatment strategy for both functional effects and underlying tissue mechanisms is summarized.

A Comprehensive Spinal Cord Injury Treatment Protocol Improves Outcomes and Decreases Complications

BACKGROUND

Spinal cord injury (SCI) is a devastating event with a complicated recovery. Through the use of an interdisciplinary team a comprehensive care plan was developed, utilizing all available best practices, to prevent secondary complications. Previous work has shown the benefit of single system protocols or interventions. This study aimed to assess changes in outcomes after implementation of a comprehensive protocol.

MATERIAL AND METHODS

This was a retrospective cohort study performed at an ACS Level I trauma center. It was based on data abstract from the institutions trauma registry over a 10 year period. Patients with quadriplegia after a traumatic injury were included. Data on hospital outcomes and complications was collected and compared before and after the use of the Spinal cord injury protocol.

RESULTS

58 patients were evaluated. Overall, there was a reduction in complications after the implementation, with significant reductions in pneumonia (47% vs 16%; P = .02) and decubitus ulcers (47% to 11%; P = .005). ICU length of stay decreased by 7 days and hospital length of stay decreased 13 days. There was no difference in mortality. Hospital costs also decreased a mean of $42,000.

CONCLUSIONS

A comprehensive SCI protocol can reduce secondary complications in quadriplegic patients. This study found significant decreases in pneumonia and decubitus ulcer rates after implementation of the protocol. Lengths of stay and cost were also significantly reduced. Future research using comprehensive SCI protocols is needed to further assess its effects on outcomes for this specific patient population. Similar centers should consider adoption of comprehensive SCI protocols.

Inspiratory Muscle Performance and Anthropometric Measures-Novel Assessments Related to Pulmonary Function in People with Spinal Cord Injury: A Pilot Study

OBJECTIVE

To investigate the feasibility and validity of using the novel axillary:umbilical (A:U) ratio and sustained maximal inspiratory pressure (SMIP) as supplementary measures in the assessment of respiratory function in people with spinal cord injury.

DESIGN

Pilot study with a single day of data collection. All measurements were taken with participants in their personal wheelchairs to best represent normal functioning and positioning for each individual.

SETTING

Research institution.

PARTICIPANTS

A convenience sample of 30 community dwelling volunteers with chronic spinal cord injury (C2-T12, American Spinal Injury Association Impairment Scale A-D) participated.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Participants underwent anthropometric measurements (trunk height, abdominal circumference, axillary circumference) and assessment of inspiratory muscle performance, incluidng maximal inspiratory pressure, SMIP, and inspiratory duration, as well as standard pulmonary function tests.

RESULTS

The A:U ratio and SMIP were recorded for all participants. The SMIP was significantly related to more respiratory performance measures than the maximal inspiratory pressure (P<.05) and the A:U ratio was significantly related to more respiratory performance measures than any other anthropometric measure (P<.05). Additionally, an A:U ratio cutoff point detected individuals with a peak expiratory flow ≥ 80% of their predicted value with a sensitivity and specificity of 85.7% and 91.3%, respectively (area under the curve: 0.92).

CONCLUSIONS

It is feasible to capture the A:U Ratio and SMIP in individuals with spinal cord injury. Further, the strong significant relationships of SMIP and the A:U ratio to respiratory performance measures suggests their clinical importance in the pulmonary assessment and risk stratification of people with chronic spinal cord injury.

Effects of Respiratory Muscle Training on Baroreflex Sensitivity, Respiratory Function, and Serum Oxidative Stress in Acute Cervical Spinal Cord Injury

Background: respiratory complications are a leading cause of morbidity and mortality in individuals with spinal cord injury (SCI). We examined the effects of respiratory muscle training (RMT) in patients with acute cervical SCI. Methods: this prospective trial enrolled 44 adults with acute cervical SCI, of which twenty received RMT and twenty-four did not receive RMT. Respiratory function, cardiovascular autonomic function, and reactive oxidative species (ROS) were compared. The experimental group received 40-min high-intensity home-based RMT 7 days per week for 10 weeks. The control group received a sham intervention for a similar period. The primary outcomes were the effects of RMT on pulmonary and cardiovascular autonomic function, and ROS production in individuals with acute cervical SCI. Results: significant differences between the two groups in cardiovascular autonomic function and the heart rate response to deep breathing (p = 0.017) were found at the 6-month follow-up. After RMT, the maximal inspiratory pressure (p = 0.042) and thiobarbituric acid-reactive substances (TBARS) (p = 0.006) improved significantly, while there was no significant difference in the maximal expiratory pressure. Significant differences between the two groups in tidal volume (p = 0.005) and the rapid shallow breathing index (p = 0.031) were found at 6 months. Notably, the SF-36 (both the physical (PCS) and mental (MCS) component summaries) in the RMT group had decreased significantly at the 6-month follow-up, whereas the clinical scores did not differ significantly (p = 0.333) after RMT therapy. Conclusions: High-intensity home-based RMT can improve pulmonary function and endurance and reduce breathing difficulties in patients with respiratory muscle weakness after injury. It is recommended for rehabilitation after spinal cord injury.

Physiological tests of small airways function in diagnosing asthma: a systematic review

BACKGROUND

Asthma is a common, heterogeneous disease that is characterised by chronic airway inflammation and variable expiratory airflow limitation. Current guidelines use spirometric measures for asthma assessment. This systematic review aimed to assess whether the most commonly reported tests of small airways function could contribute to the diagnosis of asthma.

METHODS

Standard systematic review methodology was used, and a range of electronic databases was searched (Embase, MEDLINE, CINAHL, CENTRAL, Web of Science, DARE). Studies that included physiological tests of small airways function to diagnose asthma in adults were included, with no restrictions on language or date. The risk of bias and quality assessment tools used were Agency for Healthcare Research and Quality tool for cross-sectional studies and Quality Assessment of Diagnostic Accuracy Studies 2 for diagnostic test accuracy (DTA) studies.

RESULTS

7072 studies were identified and 10 studies met review criteria. 7 included oscillation techniques and 5 included maximal mid-expiratory flow (MMEF). Studies were small and of variable quality. In oscillometry, total resistance (R5) and reactance at 5 Hz (X5) was altered in asthma compared with healthy controls. The percentage predicted of MMEF was lower in patients with asthma compared with controls in all studies and lower than the % predicted forced expiratory volume in 1 s. In DTA of oscillometry, R5 showed a sensitivity between 69% and 72% and specificity between 61% and 86%.

CONCLUSION

There were differences in the results of physiological tests of small airway function in patients with asthma compared with controls. However, studies are small and heterogeneous. Further studies are needed to assess the effectiveness of these tests on a larger scale, including studies to determine which test methodology is the most useful in asthma.

Improvement in Pulmonary Function with Short-term Rehabilitation Treatment in Spinal Cord Injury Patients

Cervical and upper thoracic spinal cord injury causes impairments in respiratory muscle performance, leading to variable degrees of pulmonary dysfunction and rendering deep breathing difficult for affected individuals. In this retrospective study, we investigated the effects of self-directed respiratory muscle training in this context by assessing pulmonary function relative to spinal cord injury characteristics. A total of 104 spinal cord injury patients (tetraplegia/paraplegia; 65/39, acute/subacute/chronic; 14/42/48) were admitted for short-term (4–8 weeks) in-patient clinical rehabilitation. Initial evaluation revealed a compromised pulmonary function with a percentage of predicted value of 62.0 and 57.5 in forced vital capacity in supine and forced vital capacity in sitting positions, respectively. Tetraplegic patients had more compromised pulmonary function compared with paraplegic patients. At follow-up evaluation, the percentage of predicted value of forced vital capacity in supine and sitting position improved overall on average by 11.7% and 12.7%, respectively. The peak cough flow improved by 22.7%. All assessed pulmonary function parameters improved significantly in all subgroups, with the greatest improvements found in patients with tetraplegia and subacute spinal cord injury. Therefore, short-term self-directed respiratory muscle training should be incorporated into all spinal cord injury rehabilitation regimens, especially for patients with tetraplegia and subacute spinal cord injury, as well as those with chronic spinal cord injury.

Forced vital capacity and cross-domain late-onset Pompe disease outcomes: an individual patient-level data meta-analysis

Background

Late-onset Pompe disease (LOPD) is a rare, metabolic disease primarily affecting the musculoskeletal and respiratory systems. Forced vital capacity (FVC) is commonly used to measure pulmonary function; however, associations between FVC and other LOPD outcomes remain unclear.

Methods

A systematic literature review was conducted on November 2015, updated September 2016 and supplemented with clinical trial data from the sponsor. Outcomes included: 6-min walk test distance (6MWT), FVC, maximal inspiratory/expiratory pressure (MIP/MEP), Medical Research Council-skeletal muscle strength score (MRC), 36-item short-form survey-physical component score (SF-36), Rotterdam Handicap Scale (RHS), Fatigue Severity Scale (FSS) and survival. Individual patient data meta-analysis was used for cross-sectional analyses and longitudinal analyses to determine associations between percent of predicted FVC and LOPD measures and outcomes.

Results

Fifteen studies were selected. From cross-sectional analyses, FVC and MRC were most strongly associated. Specifically, patients with 10% higher FVC (a round number for illustrative purposes only) were associated with a 4.72% (95% confidence interval [CI]: 3.37, 6.07) higher MRC score, indicating a positive association. Similarly, slopes for the 6MWT and SF-36 relative to a 10% higher FVC were estimated at 33.2 meters (95% CI 24.0, 42.4) and 1.2% (95% CI 0.24, 2.16%), respectively. From longitudinal analyses, a 10% incremental increase in predicted FVC was associated with an average increase of 4.12% in MRC score (95% CI 1.29, 6.95), 35.6 m in the 6MWT (95% CI 19.9, 51.6), and 1.34% in SF-36 (95% CI 0.08, 2.60). There was insufficient data to conduct analyses for RHS, FSS and survival.

Conclusions

FVC is positively associated with LOPD measures and outcomes across multiple domains. Additionally, longitudinal changes in FVC are positively associated with changes in the 6MWT, MRC and SF-36.

Electronic supplementary material

The online version of this article (10.1007/s00415-019-09401-1) contains supplementary material, which is available to authorized users.

Respiratory functional and motor control deficits in children with spinal cord injury

Children with spinal cord injury (SCI) are at high risk for developing complications due to respiratory motor control deficits. However, underlying mechanisms of these abnormalities with respect to age, development, and injury characteristics are unclear. To evaluate the effect of SCI and age on respiratory motor control in children with SCI, we compared pulmonary function and respiratory motor control outcome measures in healthy typically developing (TD) children to age-matched children with chronic SCI. We hypothesized that the deficits in respiratory functional performance in children with SCI are due to the abnormal and age-dependent respiratory muscle activation patterns. Fourteen TD (age 7±2 yrs., Mean±SD) and twelve children with SCI (age 6±1 yrs.) were evaluated by assessing Forced Vital Capacity (FVC); Forced Expiratory Volume in 1sec (FEV₁); and respiratory electromyographic activity during maximum inspiratory and maximum expiratory airway pressure measurements (PI_max and PE_max). The results indicate a significant reduction (p<.01) of FVC, FEV₁ and PE_max values in children with SCI compared to TD controls. During PE_max assessment, children with SCI produced significantly decreased (p<.01) activation of respiratory muscles below the neurological level of injury (rectus abdominous and external oblique muscles). In addition, children with SCI had significantly increased (p<.05) compensatory muscle activation above the level of injury (upper trapezius muscle). In the TD group, age, height, and weight significantly (p<.05) contributed towards increase in FVC and FEV₁. In children with SCI, only age was significantly (p<.05) correlated with FVC and FEV₁ values. These findings indicate the degree of SCI-induced respiratory functional and motor control deficits in children are age-dependent.

Plasma Leptin and Reduced FEV1 and FVC in Chronic Spinal Cord Injury

BACKGROUND

Adipose tissue produces leptin, which is pro-inflammatory, and adiponectin, which has anti-inflammatory properties. Participants with chronic spinal cord injury (SCI) have increased body fat and are at increased risk for respiratory illness.

OBJECTIVE

To assess the associations between leptin and adiponectin with pulmonary function in a chronic SCI cohort.

DESIGN

Cross-sectional study.

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

A total of 285 participants (237 men and 48 women) with chronic SCI with mean (standard deviation) injury duration 17.8 (13.2) years from the VA Boston and the community participating in an epidemiologic study assessing factors associated with respiratory health.

METHODS

Participants (24.6% cervical American Spinal Injury Association Impairment Scale (AIS) level A, B, and C; 33.6% other AIS A, B, and C; 41.8% AIS D) provided a blood sample, completed a respiratory health questionnaire, and underwent spirometry. Linear regression methods were used to assess cross-sectional associations between plasma leptin and adiponectin with spirometric measures of pulmonary function adjusted for age, race, gender, and height. Level and severity of SCI, mobility mode, body mass index, smoking, chronic obstructive pulmonary disease, asthma, chest injury history, laboratory batch, and other potential confounders were also considered.

MAIN OUTCOME MEASUREMENTS

forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC.

RESULTS

There was a statistically significant inverse relationship between plasma leptin assessed in quartiles or as a continuous covariate with FEV₁ and FVC. In fully adjusted models, each interquartile range (16,214 pg/mL) increase in leptin was associated with a significant decrease in FEV₁ (-93.1 mL; 95% confidence interval = -166.2, -20.0) and decrease in FVC (-130.7 mL; 95% confidence interval = -219.4, -42.0). There were no significant associations between leptin and FEV₁/FVC or between plasma adiponectin with FEV₁, FVC, or FEV₁/FVC.

CONCLUSION

Plasma leptin in individuals with chronic SCI is inversely associated with FEV₁ and FVC, independently of SCI level and severity and other covariates. This finding suggests that plasma leptin may contribute to reduced pulmonary function in chronic SCI.

LEVEL OF EVIDENCE

II.

Effects of Respiratory Training on Heart Rate Variability and Baroreflex Sensitivity in Individuals With Chronic Spinal Cord Injury

OBJECTIVE

To evaluate the effects of pressure threshold respiratory training (RT) on heart rate variability and baroreflex sensitivity in persons with chronic spinal cord injury (SCI).

DESIGN

Before-after intervention case-controlled clinical study.

SETTING

SCI research center and outpatient rehabilitation unit.

PARTICIPANTS

Participants (N=44) consisted of persons with chronic SCI ranging from C2 to T11 who participated in RT (n=24), and untrained control subjects with chronic SCI ranging from C2 to T9 (n=20).

INTERVENTIONS

A total of 21±2 RT sessions performed 5 days a week during a 4-week period using a combination of pressure threshold inspiratory and expiratory devices.

MAIN OUTCOME MEASURES

Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), and beat-to-beat arterial blood pressure and heart rate changes during the 5-second-long maximum expiratory pressure maneuver (5s MEP) and the sit-up orthostatic stress test, acquired before and after the RT program.

RESULTS

In contrast to the untrained controls, individuals in the RT group experienced significantly increased FVC and FEV₁ (both P<.01) in association with improved quality of sleep, cough, and speech. Sympathetically (phase II) and parasympathetically (phase IV) mediated baroreflex sensitivity both significantly (P<.05) increased during the 5s MEP. During the orthostatic stress test, improved autonomic control over heart rate was associated with significantly increased sympathetic and parasympathetic modulation (low- and high-frequency change: P<.01 and P<.05, respectively).

CONCLUSIONS

Inspiratory-expiratory pressure threshold RT is a promising technique to positively affect both respiratory and cardiovascular dysregulation observed in persons with chronic SCI.

Cardiovascular disease risk in people with spinal cord injury: is there a possible association between reduced lung function and increased risk of diabetes and hypertension?

STUDY DESIGN

Retrospective, descriptive study of medical files 253 patients with chronic traumatic spinal cord injury (SCI).

OBJECTIVES

To determine the frequency of cardiovascular disease (CVD) risk factors in SCI people, to estimate CVD risk in this population according to the Framingham Risk Score (FRS) and to determine whether reduced lung function parameters are significant predictors of diabetes mellitus (DM) and hypertension.

SETTING

Academic Rehabilitation Hospital.

METHODS

Demographic and clinical records of the patients and lung function parameters were obtained.

RESULTS

The FRS could not be calculated in 26 (10.3%) patients because this tool is designed for adults aged 20 years and older. According to the FRS guideline, ~6.7% of the SCI patients had high risk, 5.9% of them had intermediate risk and 77.1% of the study group had low risk for CVD. Regression analysis showed that impaired lung function parameters (FEV1, FVC and MVV) were significant predictors for the future development of hypertension (odds ratio (OR): 0.483 (0.258-0.903 95% confidence interval (CI)), OR: 0.549 (0.319-0.946 95% CI) and OR: 0.981 (0.965-0.998 95% CI), respectively) and DM (OR: 0.335 (0.140-0.801 95% CI), OR: 0.391 (0.183-0.839 95% CI) and OR: 0.970 (0.947-0.993 95% CI), respectively) in the SCI population.

CONCLUSION

This study showed that there might be a significant relationship between reduced lung function and the risk of DM and hypertension in people with SCI. Therefore, systematic measurement of these parameters should be performed in the routine clinical follow-up of SCI patients. Once reduced lung parameters are determined, the higher risk for developing hypertension and DM should be considered.

Cross-sectional associations of pulmonary function with systemic inflammation and oxidative stress in individuals with chronic spinal cord injury

CONTEXT/OBJECTIVE

Systemic inflammation, and to a lesser extent oxidative stress, have been associated with reduced pulmonary function. Our objective was to evaluate the associations between biomarkers of inflammation (C-reactive protein (CRP), interleukin-6 (IL-6)) and novel makers of global oxidative stress (fluorescent oxidation products (FLOx)) with spirometric and lung volume measures in individuals with chronic spinal cord injury (SCI).

DESIGN

Cross-sectional study.

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

One-hundred thirty-seven men with chronic SCI participating in an epidemiologic study.

METHODS

Participants provided a blood sample, completed health questionnaires, and underwent pulmonary function testing, including helium dilution measurement of functional residual capacity (FRC). General linear models were used to model associations between increasing quartiles of inflammation or oxidative stress with each outcome measure, after adjustment for a number of potential confounders.

OUTCOME MEASURES

Percent-predicted forced vital capacity in one second (FEV1), percent-predicted forced vital capacity (FVC), FEV1/FVC, percent-predicted residual volume (RV), percent-predicted FRC, and percent-predicted total lung capacity (TLC).

RESULTS

After adjustment for a number of confounders, participants with higher levels of CRP and IL-6 had lower percent-predicted FEV1 and FVC measurements. There were no clear patterns of association with any of the oxidative stress biomarkers or other outcome measures.

CONCLUSION

Increased systemic inflammation was associated with reductions in FEV1 and FVC independent of a number of covariates. Although the mechanism is uncertain, these results suggest that reductions in pulmonary function in SCI are associated with systemic inflammation.

The influence of regular physical activity on lung function in paraplegic people

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

The main goal of this study was to examine the influence of regular physical activity (PA) on lung volumes and flows.

SETTING

The study was conducted in the Vall d'Hebrón Hospital, Barcelona (Spain), and La Fe Hospital, Valencia (Spain).

METHODS

Spirometric tests were performed to 67 paraplegics, and differences were established between the active group (AG) (n=37) that performed >60 min per week of moderate-to-vigorous PA (MVPA) and 30 non-AG (NAG). Further, we established the relationship between the spirometric and PA variables and between being active and reaching the lower limit of normal (LLN) of the spirometric variables.

RESULTS

AG had greater values than the NAG: FVC (P<0.01), FEV₁ (P<0.01) and PEF (P<0.01). Moderate correlations between the MVPA and FVC (r=0.41, P<0.01) and the MVPA and FEV₁ (r=0.39, P<0.01) were obtained. The relationship between being physically active and reaching the LLN was statistically significant for FEV₁ (χ²=6.184, P<0.05) but not for FVC (P>0.05).

CONCLUSIONS

The performance of MVPA for a minimum of 60 min per week can have a beneficial effect, both on lung volumes and on expiratory flow, and led to an achievement of the LLN in FEV₁.

Resistive inspiratory muscle training in people with spinal cord injury during inpatient rehabilitation: a randomized controlled trial

BACKGROUND

People with spinal cord injury (SCI) may benefit from resistive inspiratory muscle training (RIMT). Current evidence is weak, and little is known about the effect on functional outcomes and long-term effects.

OBJECTIVE

The purpose of this study was to assess immediate and long-term effects of RIMT in people with SCI.

DESIGN

This was a single-blinded randomized controlled trial.

SETTING

The study was conducted at 4 specialized SCI units in the Netherlands.

PATIENTS

The study participants were 40 people with SCI (15 with motor complete tetraplegia, 16 with incomplete tetraplegia, 8 with motor complete paraplegia, and 1 with incomplete paraplegia) who had impaired pulmonary function and were admitted for initial inpatient rehabilitation.

INTERVENTION

Study participants were randomized to an RIMT group or a control group. All participants received usual rehabilitation care. In addition, participants in the intervention group performed RIMT with a threshold trainer.

MEASUREMENTS

Measurements were performed at baseline, after 8 weeks of intervention, 8 weeks later, and 1 year after discharge from inpatient rehabilitation. Primary outcome measures were: respiratory muscle function, lung volumes and flows, and perceived respiratory function. Secondary outcome measures concerned patient functioning, which included health-related quality of life, limitations in daily life due to respiratory problems, and respiratory complications.

RESULTS

During the intervention period, maximum inspiratory pressure (MIP) improved more in the RIMT group than in the control group (11.7 cm H2O, 95% confidence interval=4.3 to 19.0). At follow-up, this effect was no longer significant. No effect on other primary or secondary outcome measures was found except for an immediate effect on mental health.

LIMITATIONS

The sample size was insufficient to study effects on respiratory complications.

CONCLUSIONS

Resistive inspiratory muscle training has a positive short-term effect on inspiratory muscle function in people with SCI who have impaired pulmonary function during inpatient rehabilitation.

Associations with chest illness and mortality in chronic spinal cord injury

OBJECTIVE

Identify factors associated with chest illness and describe the relationship between chest illness and mortality in chronic spinal cord injury (SCI).

DESIGN

Cross-sectional survey assessing chest illness and a prospective assessment of mortality.

METHODS

Between 1994 and 2005, 430 persons with chronic SCI (mean ± SD), 52.0 ± 14.9 years old, and ≥4 years post SCI (20.5 ± 12.5 years) underwent spirometry, completed a health questionnaire, and reported any chest illness resulting in time off work, indoors, or in bed in the preceding 3 years. Deaths through 2007 were identified. Outcome measures Logistic regression assessing relationships with chest illness at baseline and Cox regression assessing the relationship between chest illness and mortality.

RESULTS

Chest illness was reported by 139 persons (32.3%). Personal characteristics associated with chest illness were current smoking (odds ratio =2.15; 95% confidence interval =1.25-3.70 per each pack per day increase), chronic obstructive pulmonary disease (COPD) (3.52; 1.79-6.92), and heart disease (2.18; 1.14-4.16). Adjusting for age, subjects reporting previous chest illness had a non-significantly increased hazard ratio (HR) for mortality (1.30; 0.88-1.91). In a multivariable model, independent predictors of mortality were greater age, SCI level and completeness of injury, diabetes, a lower %-predicted forced expiratory volume in 1 second, heart disease, and smoking history. Adjusting for these covariates, the effect of a previous chest illness on mortality was attenuated (HR = 1.15; 0.77-1.73).

CONCLUSION

In chronic SCI, chest illness in the preceding 3 years was not an independent risk factor for mortality and was not associated with level and completeness of SCI, but was associated with current smoking, physician-diagnosed COPD, and heart disease history.

Respiratory motor function in seated and supine positions in individuals with chronic spinal cord injury

This case-controlled clinical study was undertaken to investigate to what extent pulmonary function in individuals with chronic spinal cord injury (SCI) is affected by posture. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax) were obtained from 27 individuals with chronic motor-complete (n=13, complete group) and motor-incomplete (n=14, incomplete group) C2-T12 SCI in both seated and supine positions. Seated-to-supine changes in spirometrical (FVC and FEV1) and airway pressure (PImax and PEmax) outcome measures had different dynamics when compared in complete and incomplete groups. Patients with motor-complete SCI had tendency to increase spirometrical outcomes in supine position showing significant increase in FVC (p=.007), whereas patients in incomplete group exhibited decrease in these values with significant decreases in FEV1 (p=.002). At the same time, the airway pressure values were decreased in supine position in both groups with significant decrease in PEmax (p=.031) in complete group and significant decrease in PImax (p=.042) in incomplete group. In addition, seated-to-supine percent change of PImax was strongly correlated with neurological level of motor-complete SCI (ρ=-.77, p=.002). These results indicate that postural effects on respiratory performance in patients with SCI can depend on severity and neurological level of SCI, and that these effects differ depending on respiratory tasks. Further studies with adequate sample size are needed to investigate these effects in clinically specific groups and to study the mechanisms of such effects on specific respiratory outcome measures.

Impact of an abdominal binder on speech outcomes in people with tetraplegic spinal cord injury: perceptual and acoustic measures

BACKGROUND

An abdominal binder (AB) is routinely used for patients who have suffered a spinal cord injury (SCI) resulting in tetraplegia. It is thought to restore abdominal pressure and consequently improve breathing capacity and reduce postural hypotension in patients who do not have functioning abdominal muscles.

OBJECTIVE

To examine the early effects of an AB on respiratory and speech outcomes.

METHODS

Thirteen individuals who sustained an acute motor complete SCI between C3 and T1 were assessed after a 6-week trial of using an elasticized AB from the time of first mobilizing in an upright wheelchair. Assessments were made using spirometry and perceptual and acoustics speech measures based on sustained phonation, sentence recitation, and passage reading.

RESULTS

Significant improvements were found in the AB-on condition for 3 of 5 respiratory parameters (vital capacity, forced vital capacity, and forced expiratory volume in 1 second). Predominantly mild voice and speech dysfunction were noted in participants. No significant difference was found for any of the acoustic and perceptual speech parameters (maximum phonation time, vocal intensity for sentence recitation, perceptual speech characteristics, or vocal quality) between the AB conditions.

CONCLUSIONS

Despite the finding that an AB results in significant improvements in respiratory function for individuals with tetraplegic SCI, the current study did not provide evidence that an AB improves speech production.

Respiratory motor control disrupted by spinal cord injury: mechanisms, evaluation, and restoration

Pulmonary complications associated with persistent respiratory muscle weakness, paralysis, and spasticity are among the most important problems faced by patients with spinal cord injury when lack of muscle strength and disorganization of reciprocal respiratory muscle control lead to breathing insufficiency. This review describes the mechanisms of the respiratory motor control and its change in individuals with spinal cord injury, methods by which respiratory function is measured, and rehabilitative treatment used to restore respiratory function in those who have experienced such injury.

Evaluation of respiratory muscle activation using respiratory motor control assessment (RMCA) in individuals with chronic spinal cord injury

During breathing, activation of respiratory muscles is coordinated by integrated input from the brain, brainstem, and spinal cord. When this coordination is disrupted by spinal cord injury (SCI), control of respiratory muscles innervated below the injury level is compromised leading to respiratory muscle dysfunction and pulmonary complications. These conditions are among the leading causes of death in patients with SCI. Standard pulmonary function tests that assess respiratory motor function include spirometrical and maximum airway pressure outcomes: Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), Maximal Inspiratory Pressure (PImax) and Maximal Expiratory Pressure (PEmax). These values provide indirect measurements of respiratory muscle performance(6). In clinical practice and research, a surface electromyography (sEMG) recorded from respiratory muscles can be used to assess respiratory motor function and help to diagnose neuromuscular pathology. However, variability in the sEMG amplitude inhibits efforts to develop objective and direct measures of respiratory motor function. Based on a multi-muscle sEMG approach to characterize motor control of limb muscles, known as the voluntary response index (VRI), we developed an analytical tool to characterize respiratory motor control directly from sEMG data recorded from multiple respiratory muscles during the voluntary respiratory tasks. We have termed this the Respiratory Motor Control Assessment (RMCA). This vector analysis method quantifies the amount and distribution of activity across muscles and presents it in the form of an index that relates the degree to which sEMG output within a test-subject resembles that from a group of healthy (non-injured) controls. The resulting index value has been shown to have high face validity, sensitivity and specificity. We showed previously that the RMCA outcomes significantly correlate with levels of SCI and pulmonary function measures. We are presenting here the method to quantitatively compare post-spinal cord injury respiratory multi-muscle activation patterns to those of healthy individuals.

Predictors of pulmonary complications in blunt traumatic spinal cord injury

OBJECT

Pulmonary complications are the most common acute systemic adverse events following spinal cord injury (SCI), and contribute to morbidity, mortality, and increased length of hospital stay (LOS). Identification of factors associated with pulmonary complications would be of value in prevention and acute care management. Predictors of pulmonary complications after SCI and their effect on neurological recovery were prospectively studied between 2005 and 2009 at the 9 hospitals in the North American Clinical Trials Network (NACTN).

METHODS

The authors sought to address 2 specific aims: 1) define and analyze the predictors of moderate and severe pulmonary complications following SCI; and 2) investigate whether pulmonary complications negatively affected the American Spinal Injury Association (ASIA) Impairment Scale conversion rate of patients with SCI. The NACTN registry of the demographic data, neurological findings, imaging studies, and acute hospitalization duration of patients with SCI was used to analyze the incidence and severity of pulmonary complications in 109 patients with early MR imaging and long-term follow-up (mean 9.5 months). Univariate and Bayesian logistic regression analyses were used to analyze the data.

RESULTS

In this study, 86 patients were male, and the mean age was 43 years. The causes of injury were motor vehicle accidents and falls in 80 patients. The SCI segmental level was in the cervical, thoracic, and conus medullaris regions in 87, 14, and 8 patients, respectively. Sixty-four patients were neurologically motor complete at the time of admission. The authors encountered 87 complications in 51 patients: ventilator-dependent respiratory failure (26); pneumonia (25); pleural effusion (17); acute lung injury (6); lobar collapse (4); pneumothorax (4); pulmonary embolism (2); hemothorax (2), and mucus plug (1). Univariate analysis indicated associations between pulmonary complications and younger age, sports injuries, ASIA Impairment Scale grade, ascending neurological level, and lesion length on the MRI studies at admission. Bayesian logistic regression indicated a significant relationship between pulmonary complications and ASIA Impairment Scale Grades A (p = 0.0002) and B (p = 0.04) at admission. Pulmonary complications did not affect long-term conversion of ASIA Impairment Scale grades.

CONCLUSIONS

The ASIA Impairment Scale grade was the fundamental clinical entity predicting pulmonary complications. Although pulmonary complications significantly increased LOS, they did not increase mortality rates and did not adversely affect the rate of conversion to a better ASIA Impairment Scale grade in patients with SCI. Maximum canal compromise, maximum spinal cord compression, and Acute Physiology and Chronic Health Evaluation-II score had no relationship to pulmonary complications.

Spinal cord injury: outcomes of ventilatory weaning and extubation

BACKGROUND

Spinal cord injury (SCI) carries potentially devastating respiratory implications depending on injury level. Optimal strategies for mechanical ventilation in this setting remain poorly described. We reviewed our experience of ventilatory weaning and extubation outcomes in this patient population.

METHODS

Eighty mechanically ventilated SCI patients over a 5-year period at a major Level I trauma center were assessed. Injury, clinical, and outcome data were extracted using our ICU database, chart, and registry data.

RESULTS

We identified 80 patients with SCI, classified by anatomic injury and motor functional level. There were no differences in injury severity between patients who were successfully extubated and those who failed (all p = NS). Seventy-four percent were extubated at the time of discharge; successful extubation was associated with lower level of cord injury (p = 0.001) and higher arrival Glasgow Coma Scale score (13.7 ± 2.6 vs. 10.8 ± 5.0, p = 0.021). Of extubation failures, 80% were due to pulmonary mechanical insufficiency, 22% inadequate pulmonary toilet, and 5% sedation or neurologic issues. Patients with weaning or extubation failures had longer ICU (29.9 days ± 24.5 days vs. 8.5 days ± 9.3 days; p < 0.001) and hospital stays (45.8 days ± 45.8 days vs. 26.6 days ± 23.9 days; p = 0.009), and higher rates of ventilator-associated pneumonia (83% vs. 15%, p < 0.001).

CONCLUSION

Higher level of SCI correlates strongly with failure to wean and extubate; despite this, a subset of patients with high cord injury who can be safely weaned and extubated exists. A multicenter study is warranted to specifically identify patients with high SCI who merit weaning and extubation trials.

International spinal cord injury pulmonary function basic data set

OBJECTIVES

To develop the International Spinal Cord Injury (SCI) Pulmonary Function Basic Data Set within the framework of the International SCI Data Sets in order to facilitate consistent collection and reporting of basic bronchopulmonary findings in the SCI population.

SETTING

International.

METHODS

The SCI Pulmonary Function Data Set was developed by an international working group. The initial data set document was revised on the basis of suggestions from members of the Executive Committee of the International SCI Standards and Data Sets, the International Spinal Cord Society (ISCoS) Executive and Scientific Committees, American Spinal Injury Association (ASIA) Board, other interested organizations and societies and individual reviewers. In addition, the data set was posted for 2 months on ISCoS and ASIA websites for comments.

RESULTS

The final International SCI Pulmonary Function Data Set contains questions on the pulmonary conditions diagnosed before spinal cord lesion,if available, to be obtained only once; smoking history; pulmonary complications and conditions after the spinal cord lesion, which may be collected at any time. These data include information on pneumonia, asthma, chronic obstructive pulmonary disease and sleep apnea. Current utilization of ventilator assistance including mechanical ventilation, diaphragmatic pacing, phrenic nerve stimulation and Bi-level positive airway pressure can be reported, as well as results from pulmonary function testing includes: forced vital capacity, forced expiratory volume in one second and peak expiratory flow. The complete instructions for data collection and the data sheet itself are freely available on the website of ISCoS (http://www.iscos.org.uk).

Systemic inflammation and reduced pulmonary function in chronic spinal cord injury

OBJECTIVE

To evaluate the relationship between systemic inflammation and pulmonary function in persons with chronic spinal cord injury (SCI).

DESIGN

Cross-sectional study.

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

Fifty-nine men with chronic SCI participating in a prior epidemiologic study.

METHODS

Standardized assessment of pulmonary function and measurement of plasma C-reactive protein (CRP) and interleukin-6 (IL-6).

MAIN OUTCOME MEASUREMENTS

Forced expiratory volume in 1 second (FEV(1)) and forced vital capacity (FVC).

RESULTS

Persons with the highest values of IL-6 had the lowest %-predicted FEV(1) and FVC. There was a significant inverse linear trend between quartile of IL-6 and %-predicted FEV(1) (P < .001) and FVC (P < .006), unadjusted and adjusted for SCI level and completeness of injury, obstructive lung disease history, smoking, and body mass index (P = .010-.039). Although not as strong as for IL-6, there also were similar trends for %-predicted FEV(1) and FVC with CRP.

CONCLUSIONS

In chronic SCI, higher levels of IL-6 and CRP were associated with a lower FEV(1) and FVC, independent of level and completeness of injury. These results suggest that the reduction of pulmonary function after SCI is related not only to neuromuscular impairment but also to factors that promote systemic inflammation.

Risk factors for chest illness in chronic spinal cord injury: a prospective study

OBJECTIVE

Chest illnesses commonly cause morbidity in persons with chronic spinal cord injury. Risk factors remain poorly characterized because previous studies have not accounted for factors other than spinal cord injury.

DESIGN

Between 1994 and 2005, 403 participants completed a respiratory questionnaire and underwent spirometry. Participants were contacted at a median of 1.7 yrs [interquartile range: 1.3-2.5 yrs] apart over a mean (SD) of 5.1 +/- 3.0 yrs and asked to report chest illnesses that had resulted in time off work, spent indoors, or in bed since prior contact.

RESULTS

In 97 participants, there were 247 chest illnesses (0.12/person-year) with 54 hospitalizations (22%). Spinal cord injury level, completeness of injury, and duration of injury were not associated with illness risk. Adjusting for age and smoking history, any wheeze (relative risk = 1.92; 95% confidence interval: 1.19, 3.08), pneumonia or bronchitis since spinal cord injury (relative risk = 2.29; 95% confidence interval: 1.40, 3.75), and physician-diagnosed chronic obstructive pulmonary disease (relative risk = 2.17; 95% confidence interval: 1.08, 4.37) were associated with a greater risk of chest illness. Each percent-predicted decrease in forced expiratory volume in 1 sec was associated with a 1.2% increase in risk of chest illness (P = 0.030).

CONCLUSIONS

In chronic spinal cord injury, chest illness resulting in time spent away from usual activities was not related to the level or completeness of spinal cord injury but was related to reduced pulmonary function, wheeze, chronic obstructive pulmonary disease, a history of pneumonia and bronchitis, and smoking.

Mechanical insufflation-exsufflation device prescription for outpatients with tetraplegia

BACKGROUND

Mechanical insufflation-exsufflation (MIE) is an option for secretion mobilization in outpatients with spinal cord injury (SCI) who lack an effective cough and are at high risk for developing pneumonia.

OBJECTIVE

To describe characteristics of persons with SCI who received MIE devices for outpatient use and compare respiratory hospitalizations before and after MIE prescription.

DESIGN

Retrospective cohort study of all persons who were prescribed MIE devices for outpatient use during 2000 to 2006 by a Veterans Affairs SCI service.

RESULTS

We identified 40 patients with tetraplegia (4.5% of population followed by the SCI service) who were prescribed MIE devices. Of these, 30 (75%) had neurologic levels of C5 or rostral, and 33 (83%) had motor-complete injuries. For chronically injured patients who were prescribed MIE for home use, there was a nonsignificant reduction in respiratory hospitalization rates by 34% (0.314/y before MIE vs 0.208/y after MIE; P = 0.21). A posthoc subgroup analysis showed a significant decline in respiratory hospitalizations for patients with significant tobacco smoking histories.

CONCLUSIONS

Mechanical insufflation-exsufflation was typically prescribed for people with motor-complete tetraplegia. Outpatient MIE usage may reduce respiratory hospitalizations in smokers with SCI. Further research of this alternative, noninvasive method is warranted in the outpatient SCI population.

Pulmonary function and spinal cord injury

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 beta(2)-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.

Predictors of cardiopulmonary hospitalization in chronic spinal cord injury

OBJECTIVE

To investigate longitudinal risk factors of hospitalization for circulatory and pulmonary diseases among veterans with chronic spinal cord injury (SCI). Circulatory and respiratory system illnesses are leading causes of death in patients with chronic SCI, yet risk factors for related hospitalizations have not been characterized.

DESIGN

Prospective cohort study.

SETTING

Veterans Affairs (VA) Boston Healthcare System, Boston, Massachusetts. PARTICIPANTS/DATA SOURCES: Veterans (N=309) greater than or equal to 1 year post-SCI from the VA Boston Chronic SCI cohort who completed a health questionnaire and underwent spirometry at study entry. Baseline data were linked to 1996 through 2003 hospitalization records from the VA National Patient Care Database.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Cardiopulmonary hospital admissions, the predictors of which were assessed by multivariate Cox regression.

RESULTS

Of 1478 admissions observed, 143 were a result of cardiopulmonary (77 circulatory and 66 respiratory) illnesses. Independent predictors were greater age (3% increase/y), hypertension, and the lowest body mass index quintile (<22.4 kg/m2). A greater percentage-predicted forced expiratory volume in 1 second was associated with reduced risk. SCI level and completeness of injury were not statistically significant after adjusting for these risk factors.

CONCLUSIONS

Cardiopulmonary hospitalization risk in persons with chronic SCI is related to greater age and medical factors that, if recognized, may result in strategies for reducing future hospitalizations.

Osteoporotic fractures and hospitalization risk in chronic spinal cord injury

Osteoporosis is a well acknowledged complication of spinal cord injury. We report that motor complete spinal cord injury and post-injury alcohol consumption are risk factors for hospitalization for fracture treatment. The clinical assessment did not include osteoporosis diagnosis and treatment considerations, indicating a need for improved clinical protocols.

INTRODUCTION

Treatment of osteoporotic long bone fractures often results in lengthy hospitalizations for individuals with spinal cord injury. Clinical features and factors that contribute to hospitalization risk have not previously been described.

METHODS

Three hundred and fifteen veterans > or = 1 year after spinal cord injury completed a health questionnaire and underwent clinical exam at study entry. Multivariate Cox regression accounting for repeated events was used to assess longitudinal predictors of fracture-related hospitalizations in Veterans Affairs Medical Centers 1996-2003.

RESULTS

One thousand four hundred and eighty-seven hospital admissions occurred among 315 participants, and 39 hospitalizations (2.6%) were for fracture treatment. Median length of stay was 35 days. Fracture-related complications occurred in 53%. Independent risk factors for admission were motor complete versus motor incomplete spinal cord injury (hazard ratio = 3.73, 95% CI = 1.46-10.50). There was a significant linear trend in risk with greater alcohol consumption after injury. Record review indicated that evaluation for osteoporosis was not obtained during these admissions.

CONCLUSIONS

Assessed prospectively, hospitalization in Veterans Affairs Medical Centers for low-impact fractures is more common in motor complete spinal cord injury and is associated with greater alcohol use after injury. Osteoporosis diagnosis and treatment considerations were not part of a clinical assessment, indicating the need for improved protocols that might prevent low-impact fractures and related admissions.

Abdominal binder use in people with spinal cord injuries: a systematic review and meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

To review the evidence for the use of an abdominal binder on breathing, speech and cardiovascular function in people who have suffered a spinal cord injury (SCI).

SETTING

Brisbane, Australia.

METHODS

A search of multiple databases (Medline, Cinahl, Cochrane, Embase, PEDro) was undertaken accompanied by the reference list evaluation of each relevant publication identified. Methodological quality of studies identified was assessed using the PEDro scale. The size of effect of an abdominal binder on outcomes was also calculated where sufficient data were reported. Further descriptive analysis was performed.

RESULTS

Eleven studies met the review inclusion criteria and employed either crossover or within subject designs. Comparison of studies involving elastic and non-elastic binders was performed. A PEDro mean score of 4.3 out of 8 (range: 3-6) was found. Meta-analysis indicated that the use of abdominal binders improved vital capacity (VC) by (weighted mean difference (95% confidence interval (CI)) 0.32 (0.09, 0.55) litres, decreased functional residual capacity (FRC) by 0.41 (0.14, 0.67) litres, but did not significantly influence total lung capacity (TLC).

CONCLUSIONS

This review found some evidence that the use of an abdominal binder improves VC, but decreases FRC when assuming the sitting or tilted position in people who have suffered SCI. Overall, the quality of the studies was poor. Available evidence is not yet sufficient to either support or discourage the use of an abdominal binder in this patient population. Further studies utilizing more methodologically rigorous designs are required.

Determinants of lung volumes in chronic spinal cord injury

OBJECTIVE

To characterize determinants of lung volumes in chronic spinal cord injury (SCI).

DESIGN

Cross-sectional.

SETTING

VA Boston Healthcare System.

PARTICIPANTS

White men (N=330) with chronic SCI.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Questionnaire responses and measurements of lung volumes.

RESULTS

Adjusted for SCI severity and stature, greater body mass index (BMI) was associated (all P<.05) with lower total lung capacity (TLC) (-38.7 mL x kg(-1) x m(-2)), functional residual capacity (FRC) (-73.9 mL x kg(-1) x m(-2)), residual volume (RV) (-40.4 mL x kg(-1) x m(-2)), and expiratory reserve volume (ERV) (-32.2 mL x kg(-1) x m(-2)). The effect of BMI on RV was most pronounced in quadriplegia (-72 mL x kg(-1) x m(-2)). Lifetime smoking was associated with a greater FRC (5.3 mL/pack-year) and RV (3.1 mL/pack-years). The effects of lifetime smoking were also greatest in quadriplegia (11 mL/pack-year for FRC; 7.8 mL/pack-year for RV). Time since injury, independent of age, was associated with a decrease in TLC, FRC, ERV, and RV (P<.05). Age was not a predictor of TLC once time since injury was considered.

CONCLUSIONS

Determinants of FRC, TLC, ERV, and RV in chronic SCI include factors related and unrelated to SCI. The mechanisms remain to be determined but likely involve the elastic properties and muscle function of the respiratory system and perhaps the effects of systemic inflammation related to adiposity. Addressing modifiable factors such as obesity, muscle stiffness, and smoking may improve respiratory morbidity and mortality in SCI by improving pulmonary function.

Longitudinal change in FEV1 and FVC in chronic spinal cord injury

RATIONALE

Although respiratory dysfunction is common in chronic spinal cord injury (SCI), determinants of longitudinal change in FEV(1) and FVC have not been assessed.

OBJECTIVES

Determine factors that influence longitudinal lung function decline in SCI.

METHODS

A total of 174 male participants (mean age of 49 and 17 yr after injury) completed a respiratory questionnaire and underwent spirometry over an average follow-up of 7.5 years (range, 4-14 yr).

MEASUREMENTS AND MAIN RESULTS

In multivariate models, longitudinal decline in FEV(1) was significantly related to continued smoking, persistent wheeze, an increase in body mass index, and respiratory muscle strength. Aging was associated with an accelerated decline in FEV(1) (for ages <40, 40-60, >60 yr: -27, -37, and -71 ml/yr, respectively). Similar effects were observed for FVC.

CONCLUSIONS

Longitudinal change in FEV(1) and FVC was not directly related to level and severity of SCI, but was attributable to potentially modifiable factors in addition to age. These results suggest that weight control, smoking cessation, trials directed at the recognition and treatment of wheeze, and efforts to improve respiratory muscle strength may slow lung function decline after SCI.

Factors associated with health-related quality of life in chronic spinal cord injury

OBJECTIVE

An important goal of rehabilitation and treatment after spinal cord injury (SCI) is to improve function and enhance health-related quality of life (HRQoL). However, previous assessments are limited by use of HRQoL instruments not specific to SCI. Although respiratory dysfunction is common in SCI, it has not been possible to assess the association of comorbid medical conditions, including respiratory symptoms and pulmonary function, to HRQoL. Therefore, we assessed whether these factors were associated with HRQoL in SCI using an SCI-specific HRQoL questionnaire.

DESIGN

In our cross-sectional study, 356 participants >or=1 yr post-SCI completed a 23-item SCI-specific HRQoL questionnaire and a detailed health questionnaire, and underwent pulmonary function testing and a neurological exam at VA Boston between 1998 and June 2003.

RESULTS

In a multivariate regression model, age, employment status, motor level and completeness of injury, and ambulatory mode (use of hand-propelled or motorized wheelchair, use of crutches or canes, or walking independently) were independently associated with HRQoL. After adjusting for these factors, chronic cough, chronic phlegm, persistent wheeze, dyspnea with activities of daily living, and lower forced expiratory volume in 1 sec and forced vital capacity were each associated with a lower HRQoL.

CONCLUSIONS

These results provide evidence for the clinical validity of our SCI-specific HRQoL instrument. We also identify potentially modifiable factors that, if addressed, may lead to HRQoL improvement in SCI.

Respiratory dysfunction and management in spinal cord injury

Respiratory dysfunction is a major cause of morbidity and mortality in spinal cord injury (SCI), which causes impairment of respiratory muscles, reduced vital capacity, ineffective cough, reduction in lung and chest wall compliance, and excess oxygen cost of breathing due to distortion of the respiratory system. Severely affected individuals may require assisted ventilation, which can cause problems with speech production. Appropriate candidates can sometimes be liberated from mechanical ventilation by phrenic-nerve pacing and pacing of the external intercostal muscles. Partial recovery of respiratory-muscle performance occurs spontaneously. The eventual vital capacity depends on the extent of spontaneous recovery, years since injury, smoking, a history of chest injury or surgery, and maximum inspiratory pressure. Also, respiratory-muscle training and abdominal binders improve performance of the respiratory muscles. For patients on long-term ventilation, speech production is difficult. Often, practitioners are reluctant to deflate the tracheostomy tube cuff to allow speech production. Yet cuff-deflation can be done safely. Standard ventilator settings produce poor speech quality. Recent studies demonstrated vast improvement with long inspiratory time and positive end-expiratory pressure. Abdominal binders improve speech quality in patients with phrenic-nerve pacers. Recent data show that the level and completeness of injury and older age at the time of injury may not be related directly to mortality in SCI, which suggests that the care of SCI has improved. The data indicate that independent predictors of all-cause mortality include diabetes mellitus, heart disease, cigarette smoking, and percent-of-predicted forced expiratory volume in the first second. An important clinical problem in SCI is weak cough, which causes retention of secretions during infections. Methods for secretion clearance include chest physical therapy, spontaneous cough, suctioning, cough assistance by forced compression of the abdomen ("quad cough"), and mechanical insufflation-exsufflation. Recently described but not yet available for general use is activation of the abdominal muscles via an epidural electrode placed at spinal cord level T9-L1.