Long-term survival of persons ventilator dependent after spinal cord injury

Trends in new injuries, prevalent cases, and aging with spinal cord injury

OBJECTIVE

To determine the characteristics of the newly injured and prevalent population with spinal cord injury (SCI) and assess trends over time.

DESIGN

Prospective cohort study.

SETTING

SCI Model Systems and Shriners Hospital SCI units.

PARTICIPANTS

The study population included people whose injuries occurred from 1935 to 2008 (N=45,442). The prevalent population was estimated based on those who were still alive in 2008. Losses to follow-up (approximately 10%) were excluded from the prevalent population.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Demographic and injury characteristics, mortality, self-reported health, rehospitalization, FIM, Craig Handicap Assessment and Reporting Technique, and the Diener Satisfaction with Life Scale.

RESULTS

Mean age at injury increased 9 years since the 1970s. Injuries caused by falls and injuries resulting in high-level tetraplegia and ventilator dependency are increasing, while neurologically complete injuries are decreasing. Discharge to a nursing home is increasing. The mean age of the prevalent population is slightly higher than that of newly injured individuals, and the percentage of incident and prevalent cases older than 60 years is the same (13%). Prevalent cases tend to be less severely injured than incident cases, and less than 5% of prevalent cases reside in nursing homes. Within the prevalent population, life satisfaction and community participation are greater among persons who are at least 30 years postinjury. These findings are a result of very high mortality rates observed after 60 years of age.

CONCLUSIONS

Within the prevalent population, the percentage of elderly persons will not increase meaningfully. Those who reach older ages will typically have incomplete and/or lower-level injuries and will have relatively high degrees of independence and overall good health.

Mechanical ventilation, health, and quality of life following spinal cord injury

OBJECTIVE

To examine differences in perceived quality of life (QOL) at 1 year postinjury between people with tetraplegia who required mechanical ventilation assistance at discharge from rehabilitation and those who did not.

DESIGN

Prospective cross-sectional examination of people with spinal cord injury (SCI) drawn from the SCI Model Systems National Database.

SETTING

Community.

PARTICIPANTS

People with tetraplegia (N=1635) who sustained traumatic SCI between January 1, 1994, and September 30, 2008, who completed a 1-year follow-up interview, including 79 people who required at least some use of a ventilator at discharge from rehabilitation.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Satisfaction With Life Scale (SWLS); Craig Handicap Assessment and Reporting Technique (CHART)-Short Form Physical Independence, Mobility, Social Integration, and Occupation subscales; Patient Health Questionnaire-9 (PHQ-9), Medical Outcomes Study 36-Item Short-Form Health Survey self-perceived health status.

RESULTS

Significant differences were found between the ventilator-user (VU) group and non-ventilator-user (NVU) group for cause of trauma, proportion with complete injury, neurologic impairment level, and number of rehospitalizations. The NVU group had significantly higher SWLS and CHART Social Integration scores than the VU group after controlling for selected covariates. The NVU group also had more positive perceived health status compared with a year previously and a lower incidence of depression assessed by using the PHQ-9 than the VU group. There were no significant differences between groups for perceived current health status.

CONCLUSIONS

People in this study who did not require mechanical ventilation at discharge from rehabilitation post-SCI reported generally better health and improved QOL compared with those who required ventilator assistance at 1 year postinjury. Nonetheless, the literature suggests that perceptions of QOL improve as people live in the community for longer periods.

[Diaphragmatic pacemaker as an alternative to mechanical ventilation in patients with cervical spinal injury]

OBJECTIVE

To verify that the diaphragmatic pacemaker is a form of respiratory support that can be used to replace a volumetric respirator in cervical spinal injury patients with cervical spinal lesion and diaphragmatic paralysis by means of its comparison with the traditional volumetric respirator.

DESIGN

Retrospective study of a prospective database and age-matched case-control study.

SETTING

Intensive Care Unit and Intermediate Care Respiratory Unit, Paraplegics National Hospital, Toledo (Spain).

PATIENTS

We collected data on all patients discharged from the Hospital with permanent respiratory support by volumetric respirator or diaphragmatic pacemaker during a follow-up period of 25 years. Personal interviews were conducted to evaluate health-related quality of life. Comparison and survival tests were used for statistical comparisons.

INTERVENTIONS

Quality of life questionnaire.

MAIN VARIABLES

The main variables collected were demographic data, hospital stay, mortality, family reintegration and health-related quality of life.

RESULTS

We evaluated the clinical records of 101 patients, 37 in the pacemaker-group and 64 in the volumetric respirator-group. Our results show that ICU admission duration and hospitalization as well as family reintegration, without significant differences, with a tendency to greater survival in pacemaker patients (18.18 versus 9.67 years by the Kaplan-Meier method, p<0.001). However, this difference becomes non-significant (p=0.06) after adjustment of the groups by age. Furthermore, better quality of life was found in these same patients with pacemakers in terms of security, communication, sociability, comfort and mobility in the patients.

CONCLUSIONS

Diaphragmatic pacemaker ventilation is an effective alternative to mechanical ventilation with similar efficacy that improve quality of life in patients with severe respiratory failure due to cervical spinal cord injury.

Standardization of data analysis and reporting of results from the International Spinal Cord Injury Core Data Set

OBJECTIVES

The objective of this study was to provide guidelines for reporting results using the International Spinal Cord Injury (SCI) Core Data Set.

SETTING

International.

METHODS

A committee was created on request of the chair of the Executive Committee for the International SCI Data Set committees. The committee developed a draft consisting of set of recommendations, which were then reviewed and approved by the entire Executive Committee.

RESULTS

Age at injury is recommended as reported by the mean, s.d., median and range. When grouped, 15-year increments are recommended as follows: 0-15, 16-30, 31-45, 46-60, 61-75 and 76+ years. For pediatric SCI, 0-5, 6-12, 13-15, 16-21 years are recommended. Time since injury should be reported by mean, s.d., median and range. The following intervals are recommended: <1 year, 1-5, 6-10, 11-15 years, and 5-year increments thereafter. Calendar time (years during which the study is conducted) is recommended grouped by either 5 or 10-year increments with years ending in 4 or 9. For 'length of stay', the mean and s.d., as well as the median is recommended for report. Severity of injury is under ordinary circumstances recommended, reported in five categories: C1-4 American Spinal Injury Association Impairment Scale grade (AIS) A, B or C; C5-8 AIS A, B or C; T1-S5 AIS A, B, or C; AIS D at any injury level; and ventilator dependent at any injury level or AIS grade.

CONCLUSION

It is expected that these recommendations can facilitate a more uniform reporting of the very basic core data on SCI. This will facilitate comparison between different SCI studies.

Survival after short- or long-term ventilation after acute spinal cord injury: a single-centre 25-year retrospective study

STUDY DESIGN

A retrospective review of acute spinal cord injury patients having assisted ventilation on or after admission between 1981 and 2005.

OBJECTIVE

To assess survival after acute ventilatory support.

SETTING

Northwest Regional Spinal Injuries Centre, Southport, England.

METHODS

Causes of death were ascertained from the Office of National Statistics. Kaplan-Meier analysis of survival was calculated according to ventilator-wean status at discharge. Risk factors were obtained by Cox regression analysis.

RESULTS

Over 50% of deaths in weaned and ventilated patients were respiratory in origin. The mean survival of weaned patients in the age group 31-45 was 19.3 compared with 10.5 years for ventilated patients (P=0.047). Those under 30 survived a further 22.1 and 18.4 years (P=0.31), while those over 45 lived for 11.0 and 8.3 years (P=0.50), values for weaned and ventilated patients, respectively. The survival advantage for weaned patients in the middle age group was less evident when the 1-year survivors were compared. The mean survival time of younger patients with diaphragm pacing was 1.8 years longer than those on mechanical ventilation (P=0.142). The variables with significant hazard ratios were any comorbidity (3.07); mechanical ventilation on discharge (2.26); and older age at injury, (3.1).

CONCLUSIONS

The survival time for patients with high tetraplegia on long-term ventilation compares with other datasets and older patients have a proportionately greater loss in life expectancy. Self-ventilating patients with tetraplegia remain at considerable risk from respiratory death and consideration needs to be given to more effective preventative measures.

Physiotherapy secretion removal techniques in people with spinal cord injury: a systematic review

OBJECTIVE

To address whether secretion removal techniques increase airway clearance in people with chronic spinal cord injury (SCI).

DATA SOURCES AND STUDY SELECTION

MEDLINE/PubMed, CINAHL, EMBASE, and PsycINFO were searched from inception to May 2009 for population keywords (spinal cord injury, paraplegia, tetraplegia, quadriplegia) paired with secretion removal-related interventions and outcomes. Inclusion criteria for articles were a research study, irrespective of design, that examined secretion removal in people with chronic SCI published in English.

REVIEW METHODS

Two reviewers determined whether articles met the inclusion criteria, abstracted information, and performed a quality assessment using PEDro or Downs and Black criteria. Studies were then given a level of evidence based on a modified Sackett scale.

RESULTS

Of 2416 abstracts and titles retrieved, 24 met the inclusion criteria. Subjects were young (mean, 31 years) and 84% were male. Most evidence was level 4 or 5 and only 2 studies were randomized controlled trials. Three reports described outcomes for secretion removal techniques in addition to cough, whereas most articles examined the immediate effects of various components of cough. Studies examining insufflation combined with manual assisted cough provided the most consistent, high-level evidence. Compelling recent evidence supports the use of respiratory muscle training or electrical stimulation of the expiratory muscles to facilitate airway clearance in people with SCI.

CONCLUSION

Evidence supporting the use of secretion removal techniques in SCI, while positive, is limited and mostly of low level. Treatments that increase respiratory muscle force show promise as effective airway clearance techniques.

Risk and protective factors for mortality after spinal cord injury

Our purpose was to systematically review research on postacute risk and protective factors for mortality after spinal cord injury including psychological, environmental, behavioral and health factors. A theoretical risk model was used to identify these sets of predictive factors and to structure this article. The majority of research identifies basic demographic (age and race) and injury factors (severity). More limited research has indicated that personality, purpose in life, income, social support and negative risk behaviors predict mortality. In terms of health factors and secondary conditions, pressure ulcers, amputations, depressive diagnosis and need for treatment also predict mortality. Interventions are needed that diminish the risk of secondary conditions and early mortality.

Clearance of the cervical spine in clinically unevaluable trauma patients

STUDY DESIGN

Meta-analytic costeffectiveness analysis.

OBJECTIVE

Our goal was to compare the results of different management strategies for trauma patients in whom the cervical spine was not clinically evaluable due to impaired consciousness, endotracheal intubation, or painful distracting injuries.

SUMMARY OF BACKGROUND DATA

We performed a structured literature review related to cervical spine trauma, radiographic clearance techniques (plain radiography, flexion/extension, CT, and MRI), and complications associated with semirigid collar use.

METHODS

Meta-analytic techniques were used to pool data from multiple sources to calculate pooled mean estimates of sensitivities and specificities of imaging techniques for cervical spinal clearance, rates of complications from various clearance strategies and from empirical use of semirigid collars. A decision analysis model was used to compare outcomes and costs among these strategies.

RESULTS

Slightly more than 7.5% of patients who are clinically unevaluable have cervical spine injuries, and 42% of these injuries are associated with spinal instability. Sensitivity of plain radiography or fluoroscopy for spinal clearance was 57% (95% CI: 57%-60%). Sensitivities for CT and MRI alone were 83% (82%-84%) and 87% (84%-89%), respectively. Complications associated with collar use ranged from 1.3% (2 days) to 7.1% (10 days) but were usually minor and short-lived. Quadriplegia resulting from spinal instability missed by a clearance test had enormous impacts on longevity, quality of life, and costs. These impacts overshadowed the effects of prolonged collar application, even when the incidence of quadriplegia was extremely low.

CONCLUSION

As currently used, neuroimaging studies for cervical spinal clearance in clinically unevaluable patients are not cost-effective compared with empirical immobilization in a semirigid collar.

Lower thoracic spinal cord stimulation to restore cough in patients with spinal cord injury: results of a National Institutes of Health-Sponsored clinical trial. Part II: clinical outcomes

OBJECTIVE

To evaluate the clinical effects of spinal cord stimulation (SCS) to restore cough in subjects with cervical spinal cord injury.

DESIGN

Clinical trial assessing the clinical outcomes and side effects associated with the cough system.

SETTING

Outpatient hospital or residence.

PARTICIPANTS

Subjects (N=9; 8 men, 1 woman) with cervical spinal cord injury.

INTERVENTIONS

SCS was performed at home by either the subjects themselves or caregivers on a chronic basis and as needed for secretion management.

MAIN OUTCOME MEASURES

Ease in raising secretions, requirement for trained caregiver support related to secretion management, and incidence of acute respiratory tract infections.

RESULTS

The degree of difficulty in raising secretions improved markedly, and the need for alternative methods of secretion removal was virtually eliminated. Subject life quality related to respiratory care improved, with subjects reporting greater control of breathing problems and enhanced mobility. The incidence of acute respiratory tract infections fell from 2.0+/-0.5 to 0.7+/-0.4 events/subject year (P<.01), and mean level of trained caregiver support related to secretion management measured over a 2-week period decreased from 16.9+/-7.9 to 2.1+/-1.6 and 0.4+/-0.3 times/wk (P<.01) at 28 and 40 weeks after implantation of the device, respectively. Three subjects developed mild hemodynamic effects that abated completely with continued SCS. Subjects experienced mild leg jerks during SCS, which were well tolerated. There were no instances of bowel or bladder leakage.

CONCLUSIONS

Restoration of cough via SCS is safe and efficacious. This method improves life quality and has the potential to reduce the morbidity and mortality associated with recurrent respiratory tract infections in this patient population.

Behavioral risk factors of mortality after spinal cord injury

OBJECTIVE

To test hypothesized relationships between multiple behavioral indicators and mortality among persons with spinal cord injury (SCI), while controlling for biographic and injury characteristics.

DESIGN

Prospective cohort study with behavioral data collected by mailed survey in late 1997 and early 1998. Mortality status was ascertained as of December 31, 2005.

SETTING

A large rehabilitation hospital in the southeastern United States.

PARTICIPANTS

Adults (N=1386) with traumatic SCI, at least 1 year postinjury.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Primary outcome was time from survey to mortality or censoring. Mortality status was determined using the National Death Index and the Social Security Death Index. There were 224 deaths (16.2%) in the full sample, and due to missing data, 188 deaths were observed in the 1251 participants included in the final statistical model.

RESULTS

Cox proportional hazards modeling identified several significant behavioral predictors of mortality. In the first set of analyses, the significance of a single behavioral variable was assessed while controlling for biographic and injury predictors. We subsequently built a comprehensive model based on an optimal group of behaviors. The best set of behavioral predictors included: smoking, binge drinking (number of episodes with 5 or more drinks), prescription medication use, and number of hours out of bed per day. Inclusion of these variables improved prediction of survival compared with biographic and injury variables alone, as the pseudo-R2 increased from .121 to .164 and the concordance from .730 to .769.

CONCLUSIONS

The results affirm the importance of avoiding basic risk behaviors, such as smoking and alcohol misuse, and affirm their importance as targets of intervention in association with SCI rehabilitation.

A prospective study of health and risk of mortality after spinal cord injury

OBJECTIVE

To test hypothesized relationships between multiple health parameters and mortality among persons with spinal cord injury (SCI) while controlling for variations in biographical and injury characteristics.

DESIGN

Prospective cohort study with health data collected in late 1997 and early 1998 and mortality status ascertained in December 2005.

SETTING

A large rehabilitation hospital in the Southeastern United States.

PARTICIPANTS

A total of 1389 adults with traumatic SCI, at least 1 year postinjury.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The primary outcome was time from survey to mortality (or time of censoring). Mortality status was determined using the National Death Index and the Social Security Death Index. There were 225 deaths (16.2%) by December 31, 2005.

RESULTS

Cox proportional hazards modeling identified several significant health predictors of mortality status, while controlling for biographic and injury factors. Two sets of analyses were conducted--the first identifying the significance of a single variable of interest and the second analysis building a comprehensive model based on an optimal group of variables. Multiple types of health conditions were associated with mortality. The best set of health predictors included probable major depression, surgeries to repair pressure ulcers, fractures and/or amputations, symptoms of infections, and days hospitalized. Inclusion of these variables, along with a general health rating, improved prediction of survival compared with biographic and injury variables alone, because the pseudo R(2) increased from .12 to .18 and the concordance from .730 to .776.

CONCLUSIONS

In addition to secondary conditions that have been the traditional focus of prevention efforts (eg, pressure ulcers, urinary tract infections), amputations, fractures, and depressive symptoms were associated with higher risk for mortality; however, further research is needed to identify the association of specific conditions with causes of death and to determine whether interventions can modify these conditions and ultimately improve survival.

Long-term survival after childhood spinal cord injury

OBJECTIVE

To determine whether persons who incur a spinal cord injury as children are at increased risk of mortality compared with persons injured as adults given comparable current age, sex, and injury severity.

METHODS

A total of 25,340 persons admitted to the National Spinal Cord Injury Statistical Center database or the National Shriners Spinal Cord Injury database who were not ventilator dependent and who survived more than 2 years after injury were included in this study. These persons contributed 274,020 person-years of data, with 3844 deaths, over the 1973-2004 study period. Data were analyzed using pooled repeated observations analysis of person-years. For each person-year the outcome variable was survival/mortality, and the explanatory variables included current age, sex, race, cause of injury, severity of injury, and age at injury (the focus of the current analysis).

RESULTS

Other factors being equal, persons who were less than 16 years of age at time of injury had a 31% (95% CI = 3%-65%) increase in the annual odds of dying compared with persons injured at older ages (P= 0.013). This increased risk did not vary significantly by current age, sex, race, injury severity, or era of injury (P > 0.05).

CONCLUSION

Life expectancy for persons injured as children appears to be slightly lower than that of otherwise comparably injured persons who suffered their injuries as adults. Nonetheless, persons who are injured young can enjoy relatively long life expectancies, ranging from approximately 83% of normal life expectancy for persons with minimal deficit incomplete injuries to approximately 50% of normal in high-cervical-level injuries without ventilator dependence.