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

Predictors of respiratory complications in patients with C5-T5 spinal cord injuries

Study design

Retrospective chart audit.

Objectives

Describing the respiratory complications and their predictive factors in patients with acute traumatic spinal cord injuries at C5–T5 level during the initial hospitalization.

Setting

Hospital Vall d’Hebron, Barcelona.

Methods

Data from patients admitted in a reference unit with acute traumatic injuries involving levels C5–T5. Respiratory complications were defined as: acute respiratory failure, respiratory infection, atelectasis, non-hemothorax pleural effusion, pulmonary embolism or haemoptysis. Candidate predictors of these complications were demographic data, comorbidity, smoking, history of respiratory disease, the spinal cord injury characteristics (level and ASIA Impairment Scale) and thoracic trauma. A logistic regression model was created to determine associations between potential predictors and respiratory complications.

Results

We studied 174 patients with an age of 47.9 (19.7) years, mostly men (87%), with low comorbidity. Coexistent thoracic trauma was found in 24 (19%) patients with cervical and 35 (75%) with thoracic injuries (p < 0.001). Respiratory complications were frequent (53%) and were associated to longer hospital stay: 83.1 (61.3) and 45.3 (28.1) days in patients with and without respiratory complications (p < 0.001). The strongest predictors of respiratory complications were: previous respiratory disease (OR 5.4, 95% CI: 1.5–19.2), complete motor function impairment (AIS A–B) (OR 4.7, 95% CI: 2.4–9.5) and concurrent chest trauma (OR 3.73, 95% CI: 1.8–7.9).

Conclusions

Respiratory complications are common in traumatic spinal cord injuries between C5–T5. We identified previous respiratory disease, complete motor function impairment and the coexistence of thoracic trauma as predictors of respiratory complications. Identification of patients at risk might help clinicians to implement preventive strategies.

Plasma vitamin D, past chest illness, and risk of future chest illness in chronic spinal cord injury (SCI): a longitudinal observational study

STUDY DESIGN

Observational study.

OBJECTIVE

Assess associations between vitamin D levels and other risk factors on future chest illness in a chronic spinal cord injury (SCI) cohort.

SETTING

Veterans Affairs Boston and the Boston, MA community.

METHODS

Between August 2009 and August 2017, 253 participants with chronic SCI were followed over a median of 3.2 years (up to 7.4 years) with two to four visits a median of 1.7 years apart. At each visit, plasma 25-hydroxyvitamin D level was obtained, spirometry performed, and a respiratory questionnaire assessing chest illnesses since last visit was completed. Repeated measures negative binomial regression was used to assess chest illness risk longitudinally.

RESULTS

At entry, 25% had deficient vitamin D levels (<20 nanograms/milliliter (ng/ml)), 52% were insufficient (20 to <30 ng/ml), and 23% were sufficient (≥30 ng/ml). Over 545 study visits, chest illnesses (n = 106) were reported by 60 participants. In multivariable models (including previous chest illness history), deficient vitamin D levels (compared with those with sufficient levels) were associated with future chest illness though with wide confidence limits (relative risk (RR) = 1.36, 95% confidence intervals (CI) = 0.74, 2.47). The strongest association with chest illness during the follow-up period was in persons who reported pneumonia/bronchitis after injury and a chest illness in the three years before study entry (RR = 7.62; 95% CI = 3.70, 15.71).

CONCLUSION

Assessed prospectively in chronic SCI, there was a suggestive association between deficient vitamin D levels and future chest illness. Past chest illness history was also strongly associated with future chest illness.

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.

Associations between vitamin D and pulmonary function in chronic spinal cord injury

CONTEXT/OBJECTIVE

Individuals with chronic spinal cord injury (SCI) have an increased risk of morbidity and mortality attributable to respiratory diseases. Previous studies in non-SCI populations suggest that vitamin D may be a determinant of respiratory health. Therefore, we sought to assess if lower vitamin D levels were associated with decreased pulmonary function in persons with chronic SCI.

DESIGN

Cross-sectional study.

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

312 participants (260 men and 52 women) with chronic SCI recruited from VA Boston and the community participating in an epidemiologic study to assess factors influencing respiratory health.

METHODS

Participants provided a blood sample, completed a respiratory health questionnaire, and underwent spirometry. Linear regression methods were used to assess cross-sectional associations between plasma 25-hydroxyviatmin D and spirometric measures of pulmonary function.

OUTCOME MEASURES

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

RESULTS

Adjusted and unadjusted for a number of confounders, there was no significant association between plasma vitamin D levels and FEV₁, FVC, or FEV₁/FVC. For example, in fully adjusted models, each 10 ng/ml increase in vitamin D was associated with a 4.4 ml (95%CI -64.4, 73.2, P = 0.90) ml change in FEV_1. Conclusion: There was no significant cross-sectional association between plasma vitamin D and FEV₁, FVC, or FEV₁/FVC in this cohort of individuals with chronic SCI.

Associations between vitamin D, adiposity, and respiratory symptoms in chronic spinal cord injury

Context/Objective Persons with chronic spinal cord injury (SCI) have an increased risk of respiratory-related morbidity and mortality and chronic respiratory symptoms are clinical markers of future respiratory disease. Therefore, we sought to assess potentially modifiable factors associated with respiratory symptoms, with a focus on circulating vitamin D and measures of body fat. Design Cross-sectional study. Setting Veterans Affairs Medical Center. Participants Three hundred forty-three participants (282 men and 61 women) with chronic SCI participating in an epidemiologic study to assess factors influencing respiratory health recruited from VA Boston and the community. Methods Participants provided a blood sample, completed a respiratory health questionnaire, and underwent dual x-ray absorptiometry (DXA) to assess % body fat. Logistic regression was used to assess cross-sectional associations between respiratory symptoms and plasma vitamin D and measures of body fat with adjustment for a number of potential confounders. Outcome Measures Chronic cough, chronic phlegm, any wheeze, persistent wheeze. Results After adjustment for a number of confounders (including smoking), participants with greater %-android, gynoid, trunk, or total body fat had increased odds ratios for any wheeze and suggestive associations with persistent wheeze, but not with chronic cough or phlegm. Vitamin D levels were not associated with any of the respiratory symptoms. Conclusion Increased body fat, but not vitamin D, was associated with wheeze in chronic SCI independent of a number of covariates.

Evaluation of a clinical implementation of a respiratory muscle training group during spinal cord injury rehabilitation

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate the clinical implementation of a respiratory muscle training group during rehabilitation of individuals with spinal cord injury.

SETTING

Spinal cord injury rehabilitation center.

METHODS

Individuals with complete or incomplete lesions during inpatient rehabilitation, level C4-T12.Ten or more training sessions of either an inspiratory or a combined in- and expiratory muscle training were performed in a group setting with respiratory function measurements before and after the training period.

RESULTS

Analysis of 79 persons. Inspiratory muscle training was performed for 7 weeks with a median of 3.1 training sessions per week. Median training intensity was at 33% of baseline PImax and 58 repetitions were performed per training session. Respiratory mucle strength parameters improved by 18-68% of baseline values and lung function parameters by 11-31% after inspiratory muscle training.The combined respiratory muscle training was performed for 13 weeks with a median of 2.8 sessions per week and 88 repetitions per training session. Median inspiratory training resistance was at 39% of baseline PImax and median expiratory training resistance was at 27% of baseline PEmax. Respiratory muscle strength parameters improved by 14-51% of baseline values and lung function parameters improved by 15-34% after the combined in- and expiratory muscle training.

CONCLUSION

Respiratory resistance training improved respiratory function of individuals with acute spinal cord injury. Even if the combined respiratory muscle training was performed with more repetitions per training and nearly twice as long, relative improvements of respiratory function parameters were comparable with isolated inspiratory muscle training.

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.

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.

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.

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.

Dose-related effect of smoking on mortality in critically ill patients: a multicentre cohort study

PURPOSE

It is uncertain whether smoking has an independent dose-related adverse effect on mortality in critically ill patients. This study assessed whether the intensity of smoking history, measured in pack-years, has a dose-related effect on mortality in critically ill patients.

METHODS

In this multicentre cohort study data were collected from six tertiary intensive care units (ICU) in Australia and New Zealand.

RESULTS

Of the 8,962 patients considered in the study, data on patients' smoking status and smoking history were available from 5,063 and 2,865 patients, respectively. Male gender, and chronic respiratory, liver and cardiovascular diseases were over-represented among smokers compared to non-smokers. Smokers had a higher risk of requiring mechanical ventilation and dying in hospital than non-smokers (10.7% vs. 6.7%, p=0.001), particularly after emergency admission. Smokers also had a longer ICU stay than non-smokers (mean 3.2 days, interquartile range 0.8-3.2 vs. 2.8 days, interquartile range 0.8-2.9; p=0.024). After adjusting for age, gender, elective surgical admission, severity of acute illness, and severe chronic illnesses, the intensity of smoking history remained significantly associated with the risk of dying in hospital. This was in a relatively linear fashion (odds ratio 1.08 per 10 pack-years increment, 95% confidence interval 1.02-1.15; p=0.02). Further grouping of smokers into active smokers and ex-smokers, or including patients with unknown smoking status in the sensitivity analyses did not change the association between the intensity of smoking history and mortality.

CONCLUSIONS

Smoking has a dose-related adverse effect on mortality of critically ill patients after adjusting for other confounders.

Smoking behavior and delivery of evidence-based care for veterans with spinal cord injuries and disorders

OBJECTIVE

Little is known about those veterans with spinal cord injuries and disorders (SCI/D) who smoke cigarettes. This study identified the factors associated with smoking in this population, motivations for smoking, and the readiness for smoking cessation. Current practices for the delivery of evidence-based tobacco cessation were also examined.

DESIGN

Methods included surveys of veterans with SCI/D, medical record reviews of current smokers, and telephone interviews with SCI/D providers.

SETTING

Six Veterans Health Administration facilities with SCI centers and one SCI clinic.

PARTICIPANTS

Survey data were analyzed for 1210 veterans, 256 medical records were reviewed, and 15 providers served as key informants.

INTERVENTIONS

Observational study.

OUTCOME MEASURES

Veterans self-reported smoking status, quit attempts, methods and care received, motivation for smoking, and health care conditions. Medical record review and informant interviews examined the tobacco cessation care provided.

RESULTS

Whereas 22% of the respondents were current smokers; 51% were past smokers. Current smokers more often reported respiratory illnesses and/or symptoms, alcohol use, pain, and depression than past or never smokers, and approximately half made quit attempts in the past year. Smokers received referral to counseling (57%) and/or prescription for medication/nicotine replacement (23%). Key informants identified difficulty of providing follow-up and patients' unwillingness to consider quitting as barriers.

CONCLUSION

Veterans with SCi/D who smoke also had other health problems. Providers offer counseling and medication, but often have difficulty following patients to arrange/provide support. Identifying other support methods such as telehealth, considering the use of combination cessation therapies, and addressing other health concerns (e.g., depression) may affect tobacco cessation in this population.