Lung mechanics in individuals with spinal cord injury: effects of injury level and posture

The Clinical Relevance of Autonomic Dysfunction, Cerebral Hemodynamics, and Sleep Interactions in Individuals Living With SCI

A myriad of physiological impairments is seen in individuals after a spinal cord injury (SCI). These include altered autonomic function, cerebral hemodynamics, and sleep. These physiological systems are interconnected and likely insidiously interact leading to secondary complications. These impairments negatively influence quality of life. A comprehensive review of these systems, and their interplay, may improve clinical treatment and the rehabilitation plan of individuals living with SCI. Thus, these physiological measures should receive more clinical consideration. This special communication introduces the under investigated autonomic dysfunction, cerebral hemodynamics, and sleep disorders in people with SCI to stakeholders involved in SCI rehabilitation. We also discuss the linkage between autonomic dysfunction, cerebral hemodynamics, and sleep disorders and some secondary outcomes are discussed. Recent evidence is synthesized to make clinical recommendations on the assessment and potential management of important autonomic, cerebral hemodynamics, and sleep-related dysfunction in people with SCI. Finally, a few recommendations for clinicians and researchers are provided.

Effect of body position on peak expiratory flow during mechanical insufflation-exsufflation in people with cervical spinal cord injury: a pilot study

This prospective pilot study investigated the influence of body position on peak cough flow (PCF) during mechanical insufflation-exsufflation (MI-E) treatment in people with tetraplegia. Fifteen participants with cervical spinal cord injury (C-SCI) were randomized into two groups, which differed in the starting position, that is, the patients were either supine or reclined. Four sessions of MI-E in alternating positions with each session comprising three different maneuvers: five voluntary coughs, five MI-E-assisted coughs, and five MI-E-assisted with manual thrusts were performed with continuous airflow measurement reporting PCF from every cough. PCF was associated with the application maneuvers, total insufflation volume (TIV), and interaction between position and maneuvers but not with the application position. The estimated mean PCF was 1.808, 3.529, and 3.925 L/s when supine and 1.672, 3.598, and 3.909 L/s when reclined from voluntary cough, MI-E, and MI-E with manual thrust, respectively. The estimated PCF change compared to voluntary cough was 1.721 (95% CI, 1.603-1.838) L/s from the combined MI-E and 2.116 (95% CI, 2.005-2.228) L/s from the MI-E with manual thrust, calculated from the linear mixed-model analysis. PCF moderately correlated with TIV (R2 = 0.64). Therefore, either position can be used for C-SCI patients as long as MI-E can be performed with manual thrust and sufficient TIV is provided.

The biomechanical implications of neck position in cervical contusion animal models of SCI

Large animal contusion models of spinal cord injury are an essential precursor to developing and evaluating treatment options for human spinal cord injury. Reducing variability in these experiments has been a recent focus as it increases the sensitivity with which treatment effects can be detected while simultaneously decreasing the number of animals required in a study. Here, we conducted a detailed review to explore if head and neck positioning in a cervical contusion model of spinal cord injury could be a factor impacting the biomechanics of a spinal cord injury, and thus, the resulting outcomes. By reviewing existing literature, we found evidence that animal head/neck positioning affects the exposed level of the spinal cord, morphology of the spinal cord, tissue mechanics and as a result the biomechanics of a cervical spinal cord injury. We posited that neck position could be a hidden factor contributing to variability. Our results indicate that neck positioning is an important factor in studying biomechanics, and that reporting these values can improve inter-study consistency and comparability and that further work needs to be done to standardize positioning for cervical spinal cord contusion injury models.

Comparison of the chemical health risk assessment of exposure to metal fumes for the furnace operator of a foundry industry using quantitative and semi-quantitative methods

Heavy metals have several adverse effects on the workers' bodies due to their accumulation in the vital organs. Besides that, the current study aimed to assess the health risk of exposure to metal fumes for furnace operators working in a foundry industry based on the three different methods. The current sectional descriptive-analytical research conducted on a foundry industry in Isfahan (Iran) in 2022. Three common methods currently available, including the Semi-Quantitative Risk Assessment Method (SQRCA) and two methods provided based on the US-EPA provided technique, were used in this study. At first, the extent of people's exposure to metal fumes of Fe, Ni, Cr, and Mn was measured. Then, the chemical risk assessment of exposure to these metals' fumes was done using the three methods, and their results were compared. The SPSS Ver.25 has been used for data analysis and comparison in the current study. Results indicated that the furnace operator's exposure to all four metals was above the allowed limit of occupational exposure. The chemical risk assessment results also showed that in the first method (US-EPA-based), the risk of exposure for all workers was acceptable, while in the second method (SQCRA), the risk level of a majority of workers was medium, and in the third method (US-EPA-based), the risk level of a majority of workers was not acceptable. Comparing the methods showed that average risk scores in the first and second methods were significant compared to the exposure to fumes with equivalent concentration (P_value<0.05). The average score of carcinogenicity risk in method 3 was significant compared to the concentration of chromium and nickel (P-_value < 0.05), but it was not significant for iron and manganese and the non-carcinogenic risk of chromium and nickel. Chemical exposure risk level for the furnace operator was approximately moderate in all three methods. In terms of complexity and information required to implement the method, all three methods were almost the same, with the difference that the results of the first method cannot be generalized to other people who have the same job conditions because individual information such as a person's weight is used to calculate its score.

Rehabilitation interventions for weaning from mechanical ventilation in patients with spinal cord injury: A systematic review

BACKGROUND

Despite the fact that weaning from mechanical ventilation (MV) is one of the main rehabilitation goals in patients with spinal cord injury (SCI), controversies are still open about the optimal rehabilitation approach.

OBJECTIVE

This systematic review aimed at characterizing the rehabilitation interventions currently available to optimize weaning from MV in SCI patients.

METHODS

On April 12nd, 2022, a systematic literature search was performed in PubMed, Scopus, Web of Science, Cochrane, and PEDro, identifying studies assessing MV patients with SCI undergoing pulmonary rehabilitation. The primary outcomes were weaning duration, MV duration, and weaning success rate. Secondary outcomes were pulmonary function, extubation or decannulation time, length of stay, and safety.

RESULTS

Out of 413 records, 14 studies were included (2 randomized controlled trials, 7 observational studies, and 5 case reports). Most of the studies assessed a comprehensive rehabilitation approach, including high tidal volume ventilation, positioning, mechanical lung recruitment maneuvers, secretion management strategies, respiratory muscle training, and electrical stimulation.

CONCLUSION

Our findings suggested that a comprehensive rehabilitation intervention might have a role in reducing MV duration in patients with SCI. Further studies are needed to better characterize the optimal rehabilitation strategies for enhancing functional recovery of patients with SCI.

Methods and Applications in Respiratory Physiology: Respiratory Mechanics, Drive and Muscle Function in Neuromuscular and Chest Wall Disorders

Individuals with neuromuscular and chest wall disorders experience respiratory muscle weakness, reduced lung volume and increases in respiratory elastance and resistance which lead to increase in work of breathing, impaired gas exchange and respiratory pump failure. Recently developed methods to assess respiratory muscle weakness, mechanics and movement supplement traditionally employed spirometry and methods to evaluate gas exchange. These include recording postural change in vital capacity, respiratory pressures (mouth and sniff), electromyography and ultrasound evaluation of diaphragmatic thickness and excursions. In this review, we highlight key aspects of the pathophysiology of these conditions as they impact the patient and describe measures to evaluate respiratory dysfunction. We discuss potential areas of physiologic investigation in the evaluation of respiratory aspects of these disorders.

Inflammation and Oxidative Stress as Common Mechanisms of Pulmonary, Autonomic and Musculoskeletal Dysfunction after Spinal Cord Injury

Simple Summary

When a spinal cord injury occurs, the neurons that regulate our voluntary movements, those involved in environment and somatic perception and those that regulate vegetative functions are affected. Once neuronal damage is established, the cells of other tissues are also affected in their functions, altering the interaction between organs and altering the proper functioning of the organism. Multiple studies in animal models, as well as in humans, have recognized as factors involved in organ damage the imbalance between the formation of highly reactive molecules called pro-oxidants and defensive mechanisms called antioxidants. Closely associated with this phenomenon, the inflammatory response is also pathologically activated. In this narrative review, we have analyzed the information involving these pathological processes at the level of the lung, the autonomic nervous system and the skeletal musculature after spinal cord injury. Knowing the abnormal functioning mechanisms that occur after a spinal cord injury not only offers a better understanding of the organic events but also offers future possibilities for therapeutic interventions that may benefit the thousands of patients suffering this pathology.

Abstract

One of the etiopathogenic factors frequently associated with generalized organ damage after spinal cord injury corresponds to the imbalance of the redox state and inflammation, particularly of the respiratory, autonomic and musculoskeletal systems. Our goal in this review was to gain a better understanding of this phenomenon by reviewing both animal and human studies. At the respiratory level, the presence of tissue damage is notable in situations that require increased ventilation due to lower thoracic distensibility and alveolar inflammation caused by higher levels of leptin as a result of increased fatty tissue. Increased airway reactivity, due to loss of sympathetic innervation, and levels of nitric oxide in exhaled air that are similar to those seen in asthmatic patients have also been reported. In addition, the loss of autonomic control efficiency leads to an uncontrolled release of catecholamines and glucocorticoids that induce immunosuppression, as well as a predisposition to autoimmune reactions. Simultaneously, blood pressure regulation is altered with vascular damage and atherogenesis associated with oxidative damage. At the muscular level, chronically elevated levels of prooxidants and lipoperoxidation associated with myofibrillar atrophy are described, with no reduction or reversibility of this process through antioxidant supplementation.

Pulmonary function testing in neuromuscular disease

Neuromuscular disorders frequently compromize pulmonary function and effective ventilation, and a thorough respiratory evaluation often can assist in diagnosis, risk assessment, and prognostication. Since many of these disorders can be progressive, serial assessments may be necessary to best define a trajectory of impairment or improvement with therapy. Patients with neuromuscular diseases may have few respiratory symptoms and limited signs of skeletal muscle weakness, but can have significant respiratory muscle weakness. A single testing modality may fail to elucidate true respiratory compromise, and often a combination of tests is recommended to fully evaluate these patients. Common tests performed in this population include measurement of flow rates, lung volumes, maximal pressures, and airways resistance. This review covers the major respiratory testing modalities available in the evaluation of these patients, emphasizing both the benefits and shortcomings of each approach. The majority of parameters are available in a standard pulmonary laboratory (flows, volumes, static pressures), although referral to a specialized center may be necessary to conclusively evaluate a given patient.

Comparison of the Levels of Hematological Parameters at Rest and after Maximum Exercise between Physically Active People with Spinal Cord Injury and Able-Bodied People

The aim of the study was to reveal the difference in the hematological reaction to the applied exercise-induced workload between the able-bodied and physically active people with cervical spinal cord injury. The study covered 11 males with spinal cord injury and 11 able-bodied persons. An incremental stress test was carried out until the maximum individual workloads were achieved. The peak oxygen uptake was measured with the use of the ergospirometric method. Venous blood test results at rest and after finishing the maximal exercise showed hemoglobin (Hb) concentration, hematocrit (HCT) value, erythrocytes (RBC), leukocytes (WBC) and platelets (PLT) counts as well as the relative percentage of granulocytes (GRA), lymphocytes (LYM), and monocytes (MON). RBC, HCT as well as Hb and PLT among people with the injury were statistically lower (p < 0.001) large effect size, than in the control group. Statistically significant difference between the test and control group, subjected to the maximal exercise stress test, was observed in the exercise induced change of the PLT [p < 0.001, (ES: 2.631)] WBC [p < 0.05, (ES: 1.429)] and the percentage of LYM and GRA [p < 0.05, (ES: 1.447) for LYM and (ES: 1.332) for GRA] between both groups, subjected to the maximal cardiac stress test on the manual cycloergometer. The analysis of the obtained results indicates that people with spinal cord injury are much more vulnerable to the occurrence of microcytic anemia compared to able-bodied people. The after-exercise percentage shift of selected subpopulations of leukocytes in both groups indicates a delayed post-exercise recovery among people with spinal cord injury.

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.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

Restoration of cough via spinal cord stimulation improves pulmonary function in tetraplegics

Background: Spinal cord injury (SCI) results in significant loss in pulmonary function secondary to respiratory muscle paralysis. Retention of secretions and atelectasis and, recurrent respiratory tract infections may also impact pulmonary function. Objective: To determine whether usage of lower thoracic spinal cord stimulation (SCS) to restore cough may improve spontaneous pulmonary function in individuals with chronic SCI. Design/Methods: 10 tetraplegics utilized SCS system on a regular daily basis. Spontaneous inspiratory capacity (IC), maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) were measured at baseline prior to usage of the device and repeated every 4-5 weeks over a 20-week period. Maximum airway pressure generation (P) during SCS (40 V, 50 Hz, 0.2 ms) at total lung capacity (TLC) with subject maximal expiratory effort, at the same timepoints were determined, as well. Results: Following daily use of SCS, mean IC improved from 1636 ± 229 to 1932 ± 239 ml (127 ± 8% of baseline values) after 20 weeks (P < 0.05). Mean MIP increased from 40 ± 7, to 50 ± 8 cmH2O (127 ± 6% of baseline values) after 20 weeks, respectively (P < 0.05). MEP also improved from 27 ± 3.7 to 33 ± 5 (127 ± 14% of baseline values) (NS). During SCS, P increased from baseline in all participants from mean 87 ± 8 cmH2O to 117 ± 14 cmH2O at weeks 20, during TLC with subject maximal expiratory effort, respectively (P < 0.05). Each subject stated that they experienced much greater ease in raising secretions with use of SCS. Conclusion: Our findings indicate that use of SCS not only improves expiratory muscle function to restore cough but also results in improvement inspiratory function, as well.

French recommendations for the management of patients with spinal cord injury or at risk of spinal cord injury

OBJECTIVES

To update the French guidelines on the management of trauma patients with spinal cord injury or suspected spinal cord injury.

DESIGN

A consensus committee of 27 experts was formed. A formal conflict-of-interest (COI) policy was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e. pharmaceutical, medical devices). The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised.

METHODS

The committee studied twelve questions: (1) What are the indications and arrangements for spinal immobilisation? (2) What are the arrangements for pre-hospital orotracheal intubation? (3) What are the objectives of haemodynamic resuscitation during the lesion assessment, and during the first few days in hospital? (4) What is the best way to manage these patients to improve their long-term prognosis? (5) What is the place of corticosteroid therapy in the initial phase? (6) What are the indications for magnetic resonance imaging in the lesion assessment phase? (7) What is the optimal time for surgical management? (8) What are the best arrangements for orotracheal intubation in the hospital environment? (9) What are the specific conditions for weaning these patients from mechanical ventilation for? (10) What are the procedures for analgesic treatment of these patients? (11) What are the specific arrangements for installing and mobilising these patients? (12) What is the place of early intermittent bladder sampling in these patients? Each question was formulated in a PICO (Patients, Intervention, Comparison, Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® Methodology.

RESULTS

The experts' work synthesis and the application of the GRADE method resulted in 19 recommendations. Among the recommendations formalised, 2 have a high level of evidence (GRADE 1+/-) and 12 have a low level of evidence (GRADE 2+/-). For 5 recommendations, the GRADE method could not be applied, resulting in expert advice. After two rounds of scoring and one amendment, strong agreement was reached on all the recommendations.

CONCLUSIONS

There was significant agreement among experts on strong recommendations to improve practices for the management of patients with spinal cord injury.

Exercise testing protocol using a roller system for manual wheelchair users with spinal cord injury

OBJECTIVE

Determine the validity and reliability of an exercise testing protocol to evaluate cardiorespiratory measures in manual wheelchair users (MWUs) with spinal cord injury (SCI) using a roller-based (RS) wheelchair system.

DESIGN

Repeated measures within-subject design.

SETTING

Community-based research laboratory.

PARTICIPANTS

Ten adults with SCI requiring the use of a manual wheelchair.

INTERVENTIONS

Not applicable.

OUTCOME MEASURES

Cardiorespiratory measures (peak oxygen consumption [VO₂peak], respiratory exchange ratio [RER], pulmonary ventilation [VE], energy expenditure [EE], heart rate [HR], accumulated kilocalories [AcKcal]) and perceived exertion (RPE) were measured during three separate maximal exercise tests using an arm crank ergometer (ACE) and an RS.

RESULTS

At maximal exertion, there were no significant differences in variables between groups, with moderate-to-strong correlations (P < 0.05, r = 0.79-0.90) for VO₂, HR, RPE, AcKcal, and rate of EE between RS and ACE trials. Significant moderate-to-strong correlations existed between RS trials for VO₂, AcKcal, rate of EE, and peak power output (P < 0.01, r = 0.77-0.97).

CONCLUSIONS

VO_2peak was highly correlated between ACE and RS trials and between the two RS trials, indicating the RS protocol to be reliable and valid for MWUs with SCI. Differences in perceived exertion and efficiency at submaximal workloads and maximal pulmonary ventilation at peak workloads indicated potential advantages to using the RS.

Arm crank ergometry improves cardiovascular disease risk factors and community mobility independent of body composition in high motor complete spinal cord injury

OBJECTIVE

Evaluate the effect of aerobic exercise using arm crank ergometry (ACE) in high motor complete (ISNCSCI A/B) spinal cord injury (SCI) as primarily related to cardiovascular disease (CVD) risk factors and functional mobility and secondarily to body composition and metabolic profiles.

DESIGN

Longitudinal interventional study at an academic medical center.

METHODS

Ten previously untrained participants (M8/F2, Age 36.7 y ± 10.1, BMI 24.5 ± 6.0) with high motor complete SCI (C7-T5) underwent ACE exercise training 30 minutes/day × 3 days/week for 10 weeks at 70% VO2Peak.

OUTCOME MEASURES

Primary outcome measures were pre- and post-intervention changes in markers of cardiovascular fitness (graded exercise testing (GXT): VO2, VO2Peak, respiratory quotient [RQ], GXT time, peak power, and energy expenditure [EE]) and community mobility (time to traverse a 100ft-5° ramp, and 12-minute WC propulsion test). Secondary outcome measures were changes in body composition and metabolic profiles (fasting and area under the curve for glucose and insulin, homeostasis model assessment [HOMA] for %β-cell activity [%β], %insulin sensitivity [%S], and insulin resistance [IR], and Matsuda Index [ISIMatsuda]).

RESULTS

Resting VO2, relative VO2Peak, absolute VO2Peak, peak power, RQ, 12-minute WC propulsion, fasting insulin, fasting G:I ratio, HOMA-%S, and HOMA-IR all significantly improved following intervention (P < 0.05). There were no changes in body composition (P>0.05).

CONCLUSIONS

Ten weeks of ACE at 70% VO2Peak in high motor complete SCI improves aerobic capacity, community mobility, and metabolic profiles independent of changes in body composition.

Pulmonary Function Testing in Neuromuscular and Chest Wall Disorders

Neuromuscular and chest wall disorders frequently compromise pulmonary function, and thorough respiratory evaluation often can assist in diagnosis, risk assessment, and prognosis. Because many of these disorders can be progressive, serial assessments are necessary to best define a trajectory of impairment (or improvement with therapy). This article covers the major respiratory testing modalities available in the evaluation of these patients, emphasizing both the benefits and shortcomings of each approach. Most parameters are available in a standard pulmonary laboratory (flows, volumes, static pressures), although referral to a specialized center may be necessary to conclusively evaluate a given patient.

Acute cervical spinal cord injury and extubation failure: A systematic review and meta-analysis

PURPOSE

Respiratory complications are the most significant cause of morbidity and mortality in acute cervical spinal cord injury (CSCI). The prevalence of extubation failure (EF) and factors associated with it are unclear. This research aimed to systematically synthesise and pool literature describing EF and associated risk factors in acute CSCI.

METHODS

A systematic review was performed using medical literature analysis and retrieval system online, cummulative index of nursing and allied health literature, excerpta medica dataBASE, and Cochrane library. Articles were screened using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. A proportion meta-analysis was conducted to pool rates of EF. Odds ratios and weighted mean differences were calculated to evaluate risk factors. The R statistical software package was used.

RESULTS

Of the 347 articles that were identified, six articles satisfied the inclusion criteria (387 participants). The pooled EF rate was 20.25% (10.13-36.38%). Type of CSCI was the only statistically significant risk factor. The odds of EF occurring were 2.76 [95% confidence interval (CI): 1.14; 6.70] times greater for complete CSCI than for incomplete CSCI.

CONCLUSIONS

One in five patients with acute cervical SCI fails extubation. The odds of EF occurring are almost three times greater in complete CSCI. Future research should aim to improve standard data sets and prospective evaluation of adjuvant therapy in the peri-extubation period.

Impact of presenting patient characteristics on surgical complications and morbidity in early onset scoliosis

This study sought to assess comorbidity profiles unique to early-onset-scoliosis (EOS) patients by employing cluster analytics and to determine the influence of isolated comorbidity clusters on perioperative complications, morbidity and mortality using a high powered administrative database. The KID database was queried for ICD-9 codes pertaining to congenital and idiopathic scoliosis from 2003, 2006, 2009, 2012. Patients <10 y/o (EOS group) were included. Demographics, incidence and comorbidity profiles were assessed. Comorbidity profiles were stratified by body systems (neurological, musculoskeletal, pulmonary, cardiovascular, renal). K-means cluster and descriptive analyses elucidated incidence and comorbidity relationships between frequently co-occurring comorbidities. Binary logistic regression models determined predictors of perioperative complication development, mortality, and extended length-of-stay (≥75th percentile). 25,747 patients were included (Age: 4.34, Female: 52.1%, CCI: 0.64). Incidence was 8.9 per 100,000 annual discharges. 55.2% presented with pulmonary comorbidities, 48.7% musculoskeletal, 43.8% neurological, 18.6% cardiovascular, and 11.9% renal; 38% had concurrent neurological and pulmonary. Top inter-bodysystem clusters: Pulmonary disease (17.2%) with epilepsy (17.8%), pulmonary failure (12.2%), restrictive lung disease (10.5%), or microcephaly and quadriplegia (2.1%). Musculoskeletal comorbidities (48.7%) with renal and cardiovascular comorbidities (8.2%, OR: 7.9 [6.6-9.4], p < 0.001). Top intra-bodysystem clusters: Epilepsy (11.7%) with quadriplegia (25.8%) or microcephaly (20.5%). Regression analysis determined neurological and pulmonary clusters to have a higher odds of perioperative complication development (OR: 1.28 [1.19-1.37], p < 0.001) and mortality (OR: 2.05 [1.65-2.54], p < 0.001). Musculoskeletal with cardiovascular and renal anomalies had higher odds of mortality (OR: 1.72 [1.28-2.29], p < 0.001) and extLOS (OR: 2.83 [2.48-3.22], p < 0.001). EOS patients with musculoskeletal conditions were 7.9x more likely to have concurrent cardiovascular and renal anomalies. Clustered neurologic and pulmonary anomalies increased mortality risk by as much as 105%. These relationships may benefit pre-operative risk assessment for concurrent anomalies and adverse outcomes. Level of Evidence: III - Retrospective Prognostic Study.

Acute Lobar Atelectasis

Lobar atelectasis (or collapse) is an exceedingly common, rather predictable, and potentially pathogenic companion to many forms of acute illness, postoperative care, and chronic debility. Readily diagnosed by using routine chest imaging and bedside ultrasound, the consequences from lobar collapse may be minor or serious, depending on extent, mechanism, patient vulnerability, abruptness of onset, effectiveness of hypoxic vasoconstriction, and compensatory reserves. Measures taken to reduce secretion burden, assure adequate secretion clearance, maintain upright positioning, reverse lung compression, and sustain lung expansion accord with a logical physiologic rationale. Both classification and logical approaches to prophylaxis and treatment of lobar atelectasis derive from a sound mechanistic knowledge of its causation.

The effect of body position on pulmonary function: a systematic review

BACKGROUND

Pulmonary function tests (PFTs) are routinely performed in the upright position due to measurement devices and patient comfort. This systematic review investigated the influence of body position on lung function in healthy persons and specific patient groups.

METHODS

A search to identify English-language papers published from 1/1998-12/2017 was conducted using MEDLINE and Google Scholar with key words: body position, lung function, lung mechanics, lung volume, position change, positioning, posture, pulmonary function testing, sitting, standing, supine, ventilation, and ventilatory change. Studies that were quasi-experimental, pre-post intervention; compared ≥2 positions, including sitting or standing; and assessed lung function in non-mechanically ventilated subjects aged ≥18 years were included. Primary outcome measures were forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC, FEV1/FVC), vital capacity (VC), functional residual capacity (FRC), maximal expiratory pressure (PEmax), maximal inspiratory pressure (PImax), peak expiratory flow (PEF), total lung capacity (TLC), residual volume (RV), and diffusing capacity of the lungs for carbon monoxide (DLCO). Standing, sitting, supine, and right- and left-side lying positions were studied.

RESULTS

Forty-three studies met inclusion criteria. The study populations included healthy subjects (29 studies), lung disease (nine), heart disease (four), spinal cord injury (SCI, seven), neuromuscular diseases (three), and obesity (four). In most studies involving healthy subjects or patients with lung, heart, neuromuscular disease, or obesity, FEV1, FVC, FRC, PEmax, PImax, and/or PEF values were higher in more erect positions. For subjects with tetraplegic SCI, FVC and FEV1 were higher in supine vs. sitting. In healthy subjects, DLCO was higher in the supine vs. sitting, and in sitting vs. side-lying positions. In patients with chronic heart failure, the effect of position on DLCO varied.

CONCLUSIONS

Body position influences the results of PFTs, but the optimal position and magnitude of the benefit varies between study populations. PFTs are routinely performed in the sitting position. We recommend the supine position should be considered in addition to sitting for PFTs in patients with SCI and neuromuscular disease. When treating patients with heart, lung, SCI, neuromuscular disease, or obesity, one should take into consideration that pulmonary physiology and function are influenced by body position.

Impact of neurological level and spinal curvature on pulmonary function in adults with spina bifida

PURPOSE

To describe pulmonary function and determine the impact of neurological level, scoliosis, and obesity on pulmonary function in people with spina bifida (SB).

METHODS

Participants with SB (N= 29) (15 females; age, 30 ± 12 years) completed spirometry and body plethysmographic lung volume testing. Univariate and multivariate regression analyses were used to describe the factors associated with pulmonary function in people with SB.

RESULTS

Distribution of category of impairment in pulmonary function was: 55% (n= 16) restricted, 6.9% (n= 2) spirometric restricted, 1 combined obstructed and restricted, and 35.5% (n= 10) normal. In univariate analyses, neurological level was negatively associated with pulmonary function parameters, i.e., forced vital capacity (FVC) (p= 0.005), forced expiratory volume in 1 second (FEV1) (p= 0.008), total lung capacity (TLC) (p= 0.001), and degree of scoliosis were inversely associated with FVC (p= 0.005), FEV1 (p= 0.003), and TLC (p= 0.004). In multivariate models, level of lesion and degree of scoliosis independently contributed to the degree of lung function impairment. Restrictive pulmonary function was observed in 9/10 (90%) of those with thoracic neurological levels and was associated with decreased inspiratory capacity (IC) and expiratory reserve volume (ERV). Lumbar level lesions were associated with either normal lung function or an isolated reduction in FVC due to reduction in only ERV and preserved TLC representing spirometric restriction.

CONCLUSIONS

High prevalence of restrictive pulmonary physiology is present in people with SB, with more rostral neurological levels and greater degree of scoliosis associated with a higher degree of pulmonary function impairment.

Acute effects of glossopharyngeal insufflation in people with cervical spinal cord injury

OBJECTIVES

To evaluate acute effects of glossopharyngeal insufflation (GI) on lung function, airway pressure (P_aw), blood pressure and heart rate (HR) in people with cervical spinal cord injury (CSCI).

DESIGN

Case-control design.

SETTING

Karolinska Institutet, Stockholm, Sweden.

PARTICIPANTS

Ten participants with CSCI suffering from lesions between C4 and C8, and ASIA classification of A or B were recruited. Ten healthy particpants familiar with GI were recruited as a reference group.

OUTCOME MEASURES

Spirometry, mean arterial blood pressure (MAP), P_aw, and HR were measured in a sitting and a supine position before, during, and after GI.

RESULTS

GI in the study group in a sitting position increased total lung capacity (TLC) by 712 ml: P < 0.001, vital capacity (VC) by 587 ml: P < 0.0001, P_aw by 13 cm H₂O: P < 0.01, and HR by 10 beats/min: P < 0.001. MAP decreased by 25 mmHg, P < 0.0001. Significant differences were observed between groups comparing baseline with GI. The reference group had a higher increase in; TLC (P < 0.01), VC (P < 0.001), P_aw (P < 0.001) and HR (P < 0.05) and a higher decrease in MAP (P < 0.001). With GI in a sitting compared to a supine position, TLC, MAP, HR, P_aw remained unchanged in the study group, while residual volume decreased in the supine position (P < 0.01).

CONCLUSION

There was a difference between the groups in the increase in TLC; VC; P_aw, HR and in the decrease in MAP with GI, however MAP, HR and P_aw responded in similar way in both groups in a sitting as well as a supine position. If performed correctly, the risks of GI resulting in clinically significant hemodynamic changes is low, although syncope may still occur.

A chronic care model for spina bifida transition

Providing comprehensive transition care for adolescents and young adults with spina bifida (AYASB) requires a structured approach to addressing chronic condition management, self-management, care coordination, and health care navigation that is adaptable to the various levels of cognitive ability, physical function, and family/community environments within the population. This commentary (1) highlights AYASB transition program needs identified in the literature and within a local community, (2) analyzes advantages and limitations of published AYASB transition care models in addressing these needs, (3) demonstrates how a spina bifida (SB) transition clinic used the Chronic Care Model (CCM) to develop a comprehensive AYASB transition program, and (4) examines the potential feasibility in adapting this model to other SB clinics. A SB-specific transition clinic based on the CCM model facilitates the complex chronic care management and transition planning for AYASB. Further study is needed to evaluate health care outcomes using the CCM for SB transition.

Evidence-based respiratory management strategies required to prevent complications and improve outcome in acute spinal cord injury patients

Spinal injuries without neurological damage have little effects on respiratory function unless associated with injury to the chest wall. Early verticalisation or mobilisation of these patients is safe and likely to improve vital capacity. Spinal injury with cord damage has a profound effect on the mechanics of respiration and on respiratory function particularly in cervical cord injuries. Around 40% of spinal cord injuries occur in the cervical spine, a trend that is steadily increasing, with respiratory causes being responsible for death in over 20% of individuals. Loss of lung volumes and relative hypoxemia contribute to global hypoxaemia, exacerbating cord ischaemia in the acute period. Respiratory compromise results in the loss of muscle strength generation capacity and reduced lung volumes and in particular vital capacity, of up to 70%, ineffective cough and secretion clearance abilities; reductions in both lung and chest wall compliance and an additional oxygen cost of breathing due to changes in respiratory mechanics, with obstructive sleep apnoea evident in over 50% of acute tetraplegics. While some countries have specialist spinal centres to manage such catastrophic trauma with a demonstrable improvement in health outcomes attributed to their contribution, many individuals are initially admitted to local hospitals where healthcare professionals are less likely to fully appreciate the significant and continued vulnerabilities of such individuals. This article aims to provide a basic understanding of the causes and identification of the main principles of the respiratory management strategies required to maintain pulmonary health for cervical spinal cord injury patients during the initial and early post trauma phase.

Effects of overground locomotor training on the ventilatory response to volitional treadmill walking in individuals with incomplete spinal cord injury: a pilot study

INTRODUCTION

Although there has been substantial emphasis on the neuromuscular and cardiovascular adaptations following rehabilitation, pulmonary adaptations in individuals with incomplete SCI (iSCI) in response to locomotor training have been less frequently studied. In healthy individuals, effective transition from rest to work is accomplished by a hyperpneic response, which exhibits an exponential curve with three phases. However, the degree to which our current understanding of exercise hyperpnea can be applied to individuals with iSCI is unknown. The purpose of this case series was to characterize exercise hyperpnea during a rest to constant work rate (CWR) transition before and after 12-15 weeks of overground locomotor training (OLT).

CASE PRESENTATION

Six subjects with cervical motor incomplete spinal cord injury participated in 12-15 weeks of OLT. Subjects were trained in 90-min sessions twice a week. All training activities were weight-bearing and under volitional control without the assistance of body-weight support harnesses, robotic devices or electrical stimulation. Six minutes of CWR treadmill walking was performed at self-selected pace with cardiorespiratory analysis throughout the tests before and after OLT. Averaged group data for tidal volume, breathing frequency or V_E showed no difference before and after training. V_E variability was decreased by 46.7% after OLT.

DISCUSSION

CWR V_E from rest to work was linear throughout the transition. Following OLT, there was a substantial reduction in V_E variability. Future research should investigate the lack of a phasic ventilatory response to exercise, as well as potential mechanisms of ventilatory variability and its implications for functional performance.

Sleep-Disordered Breathing in Neuromuscular Disease: Diagnostic and Therapeutic Challenges

Normal sleep-related rapid eye movement sleep atonia, reduced lung volumes, reduced chemosensitivity, and impaired airway dilator activity become significant vulnerabilities in the setting of neuromuscular disease. In that context, the compounding effects of respiratory muscle weakness and disease-specific features that promote upper airway collapse or cause dilated cardiomyopathy contribute to various sleep-disordered breathing events. The reduction in lung volumes with neuromuscular disease is further compromised by sleep and the supine position, exaggerating the tendency for upper airway collapse and desaturation with sleep-disordered breathing events. The most commonly identified events are diaphragmatic/pseudo-central, due to a decrease in the rib cage contribution to the tidal volume during phasic rapid eye movement sleep. Obstructive and central sleep apneas are also common. Noninvasive ventilation can improve survival and quality of sleep but should be used with caution in the context of dilated cardiomyopathy or significant bulbar symptoms. Noninvasive ventilation can also trigger sleep-disordered breathing events, including ineffective triggering, autotriggering, central sleep apnea, and glottic closure, which compromise the potential benefits of the intervention by increasing arousals, reducing adherence, and impairing sleep architecture. Polysomnography plays an important diagnostic and therapeutic role by correctly categorizing sleep-disordered events, identifying sleep-disordered breathing triggered by noninvasive ventilation, and improving noninvasive ventilation settings. Optimal management may require dedicated hypoventilation protocols and a technical staff well versed in the identification and troubleshooting of respiratory events.

Active physiological conservative management in traumatic spinal cord injuries – an evidence-based approach

The management of the traumatic spinal cord injury remains controversial. Guttmann demonstrated that with simultaneous attention to all medical and non-medical effects of the spinal cord injury, a significant number of patients recovered motor and sensory functions to ambulate and the majority were pain-free following conservative management. Active physiological conservative management of the spinal injury requires simultaneous scrupulous care of the injured spine together with; the multisystem neurogenic effects of the spinal cord injury on the respiratory, cardiovascular, urinary, gastrointestinal, dermatological, sexual and reproductive functions; the management of the associated psychological effects of paralysis from the early hours or days of injury as well as; the physical rehabilitation and modification of the environment. To date, there is no evidence to suggest that the surgical decompression and/or stabilisation of the neurologically impaired spinal cord injury patient is advantageous. This article considers the debates and evidence of surgical management including the effects of timing of the surgical decompression. Also addressed are the factors influencing decisions on management, prognostic indicators of recovery and natural history of complete and incomplete cord injuries. Traumatic biomechanical instability of the spine, physiological instability of the spinal cord, traumatic spinal canal encroachment and traumatic cord compression are also discussed. Early mobilisation, indications for surgery at the RJAH and economic considerations of spinal cord injuries are presented. The ultimate goals of the active physiological conservative management are to ensure maximum neurological recovery and independence, a pain-free and flexible spine, safe and convenient functioning of the various systems of the body with minimal inconvenience to patients and the prevention of complications.

Nanoconjugate-bound adenosine A1 receptor antagonist enhances recovery of breathing following acute cervical spinal cord injury

Respiratory complications in patients with spinal cord injury (SCI) are common and can have a negative impact on the quality of patients' lives. Previously, we found that intradiaphragmatic administration of the nanoconjugate-bound A₁ adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) induced recovery of diaphragm function following SCI in rats. When administered immediately following the injury, recovery was observed as early as 3days following SCI and it persisted until the end of the study, 28days after the drug delivery. The recovery was observed using diaphragmatic electromyography (EMG) as well as phrenic nerve recordings; both of which were conducted under anesthetized conditions. Confounding effects of anesthetic may make data interpretation complex in terms of the impact on overall ventilatory function and clinical relevance. The objective of the present study was to test the hypothesis that intradiaphragmatic administration of nanoconjugate-bound DPCPX, enhances recovery of ventilation following SCI in the unanesthetized rat. To that end, Sprague-Dawley rats underwent C2 spinal cord hemisection (C2Hx) on day 0 and received either: (i) 0.15μg/kg of nanoconjugate-bound DPCPX or (ii) vehicle control (50μl distilled water). To assess ventilation, unrestrained whole body plethysmography (WBP) was performed on day 0 (immediately before the surgery) and 3, 7, 14, 21 and 28days following the SCI. Frequency, tidal volume, and minute ventilation data were analyzed in two minute bins while the animal was calm and awake. We found that a single administration of the nanoconjugate-bound A₁ adenosine receptor antagonist facilitated recovery of tidal volume and minute ventilation following SCI. Furthermore, the treatment attenuated SCI-associated increases in respiratory frequency. Taken together, this study suggests that the previously observed DPCPX nanoconjugate-induced recovery in diaphragmatic and phrenic motor outputs may translate to a clinically meaningful improvement in ventilatory function in patients with SCI.

Comparison of volume control and pressure control ventilation in patients undergoing single level anterior cervical discectomy and fusion surgery

Background and Aims:

Pressure control and volume control ventilation are the most preferred modes of ventilator techniques available in the intraoperative period. The study compared the intraoperative ventilator and blood gas variables of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) in patients undergoing single level anterior cervical discectomy and fusion (ACDF).

Methods:

After obtaining Institutional Ethical Committee approval and informed consent, sixty patients scheduled for single level ACDF surgery performed in supine position under general anaesthesia were included. Group V (30 patients) received VCV and Group P (30 patients) received PCV. The primary objective was oxygenation variable PaO₂/FiO₂ at different points of time i.e. T1–20 min after the institution of the ventilation, T2–20 min after placement of the retractors and T3–20 min after removal of the retractors. The secondary objectives include other arterial blood gas parameters, respiratory and haemodynamic parameters. NCSS version 9 statistical software was used for statistics. Two-way repeated measures for analysis of variance with post hoc Tukey Kramer test was used to analyse continuous variables for both intra- and inter-group comparisons, paired sample t-test for overall comparison and Chi-square test for categorical data.

Results:

The primary variable PaO₂/FiO₂ was comparable in both groups (P = 0.08). The respiratory variables, PAP and C_dynam were statistically significant in PCV group compared to VCV (P < 0.05), though clinically insignificant. Other secondary variables were comparable. (P > 0.05)

Conclusion:

Clinically, both PCV and VCV group appear to be-equally suited ventilator techniques for anterior cervical spine surgery patients.

Respiratory problems and management in people with spinal cord injury

Spinal cord injury (SCI) is characterised by profound respiratory compromise secondary to the level of loss of motor, sensory and autonomic control associated with the injury. This review aims to detail these anatomical and physiological changes after SCI, and outline their impact on respiratory function. Injury-related impairments in strength substantially alter pulmonary mechanics, which in turn affect respiratory management and care. Options for treatments must therefore be considered in light of these limitations.

KEY POINTS

Respiratory impairment following spinal cord injury (SCI) is more severe in high cervical injuries, and is characterised by low lung volumes and a weak cough secondary to respiratory muscle weakness.Autonomic dysfunction and early-onset sleep disordered breathing compound this respiratory compromise.The mainstays of management following acute high cervical SCI are tracheostomy and ventilation, with noninvasive ventilation and assisted coughing techniques being important in lower cervical and thoracic level injuries.Prompt investigation to ascertain the extent of the SCI and associated injuries, and appropriate subsequent management are important to improve outcomes.

EDUCATIONAL AIMS

To describe the anatomical and physiological changes after SCI and their impact on respiratory function.To describe the changes in respiratory mechanics seen in cervical SCI and how these changes affect treatments.To discuss the relationship between injury level and respiratory compromise following SCI, and describe those at increased risk of respiratory complications.To present the current treatment options available and their supporting evidence.

Impact of voice and communication deficits for individuals with cervical spinal cord injury living in the community

BACKGROUND

Post-spinal cord injury (SCI), individuals may exhibit mild to moderate impairments in aspects of speech influenced by impaired respiratory support. However, limited research has been conducted into the impact of these impairments on activity and participation when living in the community.

AIMS

To examine the nature and extent of voice and communication function in a group of individuals with cervical SCI living in the community, and to explore participant perceptions of the impact of these deficits on levels of activity and participation.

METHODS & PROCEDURES

Participants included 14 individuals who had sustained a SCI above C8 level and had returned to living in the community. All completed a series of speech and voice assessments, the Voice Handicap Index, the Australian Therapy Outcome Measures Voice scale, four voice perception questions, and the General Short Form of the Communicative Participation Item Bank.

OUTCOMES & RESULTS

As a group, participants were found to have reduced vocal intensity and phonatory duration. Vocal quality was mildly altered in 93% and pitch control, breath support for speech, speech rate and phrase length impacted in one-quarter or more of the group. All reported impacts, though three individuals reported that their impairments had more extensive impact on communication in daily life.

CONCLUSIONS & IMPLICATIONS

Individuals post-SCI experience mild speech and voice deficits that can have negative impacts on functional communication. The monitoring of communication function may help to identify those individuals who could benefit from additional support and intervention on return to community life.

Functional Magnetic Stimulation of Inspiratory and Expiratory Muscles in Subjects With Tetraplegia

BACKGROUND

Respiratory complications are major causes of morbidity and mortality in persons with a spinal cord injury, partly because of respiratory muscle paralysis. Earlier investigation has demonstrated that functional magnetic stimulation (FMS) can be used as a noninvasive technology for activating expiratory muscles, thus producing useful expiratory functions (simulated cough) in subjects with spinal cord injury.

OBJECTIVE

To evaluate the effectiveness of FMS for conditioning inspiratory and expiratory muscles in persons with tetraplegia.

DESIGN

A prospective before and after trial.

SETTING

FMS Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, OH.

PARTICIPANTS

Six persons with tetraplegia.

METHOD

Each subject participated in a 6-week FMS protocol for conditioning the inspiratory and expiratory muscles. A magnetic stimulator was used with the center of a magnetic coil placed at the C7-T1 and T9-T10 spinous processes, respectively. Pulmonary function tests were performed before, during, and after the protocol.

MAIN OUTCOME MEASUREMENTS

Respiratory variables included maximal inspiratory pressure (MIP), inspiratory reserve volume (IRV), peak inspiratory flow (PIF), maximal expiratory pressure (MEP), expiratory reserve volume (ERV), and peak expiratory flow (PEF).

RESULTS

After 6 weeks of conditioning, the main outcome measurements (mean ± standard error) were as follows: MIP, 89.6 ± 7.3 cm H2O; IRV, 1.90 ± 0.34 L; PIF, 302.4 ± 36.3 L/min; MEP, 67.4 ± 11.1 cm H2O; ERV, 0.40 ± 0.06 L; and PEF, 372.4 ± 31.9 L/min. These values corresponded to 117%, 107%, 136%, 109%, 130%, and 124% of pre-FMS conditioning values, respectively. Significant improvements were observed in MIP (P = .022), PIF (P = .0001), and PEF (P = .0006), respectively. When FMS was discontinued for 4 weeks, these values showed decreases from their values at the end of the conditioning protocol, which suggests that continual FMS may be necessary to maintain improved respiratory functions.

CONCLUSION

FMS conditioning of the inspiratory and expiratory muscles improved voluntary inspiratory and expiratory functions. FMS may be a noninvasive technology for respiratory muscle training in persons with tetraplegia.

Effects of Krankcycle Training on Performance and Body Composition in Wheelchair Users

Innovation in training equipment is important for increasing training effectiveness, performance and changes in body composition, especially in wheelchair users with paraplegia. The main objective of a workout session is to induce an adaptation stimulus, which requires overload of involved muscles by voluntary effort, yet this overload may be highly influenced by the size of the spinal cord lesion. Krancykl construction is designed to allow exercise on any wheelchair and with adjustable height or width of crank handles, where even the grip handle may be altered. The aim of this study was to determine the differences in body composition, performance and the rate of perceived exertion (RPE) in paraplegics with a different level of paralyses after a 12 week training programme of a unilateral regime on Krankcycle equipment (a crank machine). The study sample included four men and one women at a different spine lesion level. The 12 weeks programme was successfully completed by four participants, while one subject got injured during the intervention process. Three participants were paraplegics and one was quadriplegic with innervation of the biceps humeri, triceps humeri and deltoideus. The Krankcycle 30 min programme was followed by four other exercises, which were performed after themselves rather than in a circuit training manner as the latter would result in much longer rest periods between exercises, because paraplegics have to be fixed by straps during exercise on hydraulic machines. The RPE after the workout decreased following the twelve week adaptation period.

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.

Relationship between pulmonary function and exercise capacity in individuals with spinal cord injury

OBJECTIVE

The aim of this study was to determine whether the relationship between impaired pulmonary function and level of spinal cord injury would relate to lower maximal ventilation during exercise (Vemax) and hence reduced aerobic capacity.

DESIGN

Pulmonary function and maximal aerobic capacity (V˙O2max) were assessed as measured by maximal oxygen uptake in 20 men with complete spinal cord injury (C5-T11). Static and dynamic lung volumes (forced vital capacity, forced expiratory volume in 1 sec, and maximum voluntary ventilation) were measured by spirometry. V˙O2max and Vemax were measured during a graded maximal exercise test on an arm crank ergometer.

RESULTS

Level of injury was inversely correlated with measures of pulmonary function, Vemax and V˙O2max. On the basis of the correlations, the authors constructed a path analysis to test whether level of injury indirectly (via pulmonary function and/or Vemax) or directly reduced V˙O2max. Akaike information criteria indicated that the strongest effect of level of injury on V˙O2max was via reduced Vemax.

CONCLUSIONS

Respiratory capacity does influence exercise capacity in the population with spinal cord injury and may play an important role in delimiting aerobic exercise capacity.

Respiratory nursing interventions following tracheostomy in acute traumatic cervical spinal cord injury

Tracheostomy is frequently performed in severe cervical spinal cord injury (SCI) patients with the pulmonary dysfunction. A series of respiratory nursing interventions are required to plan tracheostomy removal. Tracheostomy was performed in 29 patients after acute traumatic cervical SCI. A series of respiratory nursing interventions were introduced in these patients after closed tracheostomy and decannulation, including closed tracheostomy tube training, manually assisted cough. Chacheostomy was successfully removed in 21 patients after the respiratory nursing interventions. In contrast, eight patients died from associated injuries. The average time from tracheostomy to decannulation was 40 days (14-104 days), the average time from closed tracheostomy to decannulation was 18.80 ± 13.50 days. Second tracheostomy was performed in one patient after 29 days' removal due to pulmonary infection. One patient presented with delayed incision healing for 29 days. Closed tracheostomy tube training and manually assisted cough are key factors for tracheostomy removal, although intensive nursing are also needed. The time from tracheostomy to decannulation and from closed tracheostomy to decannulation is increased in case of "late" (>24 h) tracheostomy and longer mechanical ventilation.

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.

Sleep disordered breathing in chronic spinal cord injury

STUDY OBJECTIVES

Spinal cord injury (SCI) is associated with 2-5 times greater prevalence of sleep disordered breathing (SDB) than the general population. The contribution of SCI on sleep and breathing at different levels of injury using two scoring methods has not been assessed. The objectives of this study were to characterize the sleep disturbances in the SCI population and the associated physiological abnormalities using quantitative polysomnography and to determine the contribution of SCI level on the SDB mechanism.

METHODS

We studied 26 consecutive patients with SCI (8 females; age 42.5 ± 15.5 years; BMI 25.9 ± 4.9 kg/m2; 15 cervical and 11 thoracic levels) by spirometry, a battery of questionnaires and by attended polysomnography with flow and pharyngeal pressure measurements. Inclusion criteria for SCI: chronic SCI (> 6 months post injury), level T6 and above and not on mechanical ventilation. Ventilation, end-tidal CO2 (PETCO2), variability in minute ventilation (VI-CV) and upper airway resistance (RUA) were monitored during wakefulness and NREM sleep in all subjects. Each subject completed brief history and exam, Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Berlin questionnaire (BQ) and fatigue severity scale (FSS). Sleep studies were scored twice, first using standard 2007 American Academy of Sleep Medicine (AASM) criteria and second using new 2012 recommended AASM criteria.

RESULTS

Mean PSQI was increased to 10.3 ± 3.7 in SCI patients and 92% had poor sleep quality. Mean ESS was increased 10.4 ± 4.4 in SCI patients and excessive daytime sleepiness (ESS ≥ 10) was present in 59% of the patients. Daytime fatigue (FSS > 20) was reported in 96% of SCI, while only 46% had high-risk score of SDB on BQ. Forced vital capacity (FVC) in SCI was reduced to 70.5% predicted in supine compared to 78.5% predicted in upright positions (p < 0.05). Likewise forced expiratory volume in first second (FEV1) was 64.9% predicted in supine compared to 74.7% predicted in upright positions (p < 0.05). Mean AHI in SCI patients was 29.3 ± 25.0 vs. 20.0 ± 22.8 events/h using the new and conventional AASM scoring criteria, respectively (p < 0.001). SCI patients had SDB (AHI > 5 events/h) in 77% of the cases using the new AASM scoring criteria compared to 65% using standard conventional criteria (p < 0.05). In cervical SCI, VI decreased from 7.2 ± 1.6 to 5.5 ± 1.3 L/min, whereas PETCO2 and VI-CV, increased during sleep compared to thoracic SCI.

CONCLUSION

The majority of SCI survivors have symptomatic SDB and poor sleep that may be missed if not carefully assessed. Decreased VI and increased PETCO2 during sleep in patients with cervical SCI relative to thoracic SCI suggests that sleep related hypoventilation may contribute to the pathogenesis SDB in patients with chronic cervical SCI.

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.

Tetraplegia is a risk factor for central sleep apnea

Sleep-disordered breathing (SDB) is highly prevalent in patients with spinal cord injury (SCI); the exact mechanism(s) or the predictors of disease are unknown. We hypothesized that patients with cervical SCI (C-SCI) are more susceptible to central apnea than patients with thoracic SCI (T-SCI) or able-bodied controls. Sixteen patients with chronic SCI, level T6 or above (8 C-SCI, 8 T-SCI; age 42.5 ± 15.5 years; body mass index 25.9 ± 4.9 kg/m(2)) and 16 matched controls were studied. The hypocapnic apneic threshold and CO2 reserve were determined using noninvasive ventilation. For participants with spontaneous central apnea, CO2 was administered until central apnea was abolished, and CO2 reserve was measured as the difference in end-tidal CO2 (PetCO2) before and after. Steady-state plant gain (PG) was calculated from PetCO2 and VE ratio during stable sleep. Controller gain (CG) was defined as the ratio of change in VE between control and hypopnea or apnea to the ΔPetCO2. Central SDB was more common in C-SCI than T-SCI (63% vs. 13%, respectively; P < 0.05). Mean CO2 reserve for all participants was narrower in C-SCI than in T-SCI or control group (-0.4 ± 2.9 vs.-2.9 ± 3.3 vs. -3.0 ± 1.2 l·min(-1)·mmHg(-1), respectively; P < 0.05). PG was higher in C-SCI than in T-SCI or control groups (10.5 ± 2.4 vs. 5.9 ± 2.4 vs. 6.3 ± 1.6 mmHg·l(-1)·min(-1), respectively; P < 0.05) and CG was not significantly different. The CO2 reserve was an independent predictor of apnea-hypopnea index. In conclusion, C-SCI had higher rates of central SDB, indicating that tetraplegia is a risk factor for central sleep apnea. Sleep-related hypoventilation may play a significant role in the mechanism of SDB in higher SCI levels.