Specialized respiratory management for acute cervical spinal cord injury:: a retrospective analysis

High vs. low tidal volume and pulmonary complications in patients with cervical spinal cord injury on mechanical ventilation: systematic review

Introduction

Cervical spinal cord injury (CSCI) patients on mechanical ventilation often lack standardized guidelines for optimal ventilatory support. This study reviews existing literature to compare outcomes between high tidal volume (HTV) and low tidal volume (LTV) strategies in this unique patient population.

Methods

We searched for studies published up to August 30, 2023, in five databases, following a PECO/PICO strategy. We found six studies for quantitative analysis and meta-analyzed five studies.

Results

This meta-analysis included 396 patients with CSCI and mechanical ventilation (MV), 119 patients treated with high tidal volume (HTV), and 277 with low tidal volume (LTV). This first meta-analysis incorporates the few studies that show contradictory findings. Our meta-analysis shows that there is no significant statistical difference in developing VAP between both comparison groups (HTV vs. LTV) (OR 0.46; 95% CI 0.13 to 1.66; p > 0.05; I2: 0%), nor are there differences between the presence of other pulmonary complications when treating with HTV such as acute respiratory distress syndrome (ARDS), atelectasis, onset of weaning.

Conclusion

In patients with CSCI in MV, the use of HTV does not carry a greater risk of pneumonia compared to LTV; in turn, it is shown as a safe ventilatory strategy as it does not establish an increase in other pulmonary complications such as ARDS, atelectasis, the onset of weaning nor others associated with volutrauma. It is necessary to evaluate the role of HTV ventilation in this group of patients in primary RCT-type studies.

Traumatic spinal cord injury: acute phase treatment in critical care

PURPOSE OF REVIEW

Surgical timing in traumatic spinal cord injury (t-SCI) remains a point of debate. Current guidelines recommend surgery within 24 h after trauma; however, earlier timeframes are currently intensively being investigated. The aim of this review is to provide an insight on the acute care of patients with t-SCI.

RECENT FINDINGS

Multiple studies show that there appears to be a beneficial effect on neurological recovery of early surgical decompression within 24 h after trauma. Currently, the impact of ultra-early surgery is less clear as well as lacking evidence for the most optimal surgical technique. Nevertheless, early surgery to decompress the spinal cord by whatever method can impact the occurrence for perioperative complications and potentially expedite rehabilitation. There are clinical and socioeconomic barriers in achieving timely and adequate surgical interventions for t-SCI.

SUMMARY

In this review, we provide an overview of the recent insights of surgical timing in t-SCI and the current barriers in acute t-SCI treatment.

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.

Oropharyngeal Dysphagia in Acute Cervical Spinal Cord Injury: A Literature Review

Dysphagia (swallowing impairment) is a frequent complication of cervical spinal cord injury (cSCI). Recently published national guidance in the UK on rehabilitation after traumatic injury confirmed that people with cSCI are at risk for dysphagia and require early evaluation while remaining nil by mouth [National Institute for Health and Care Excellence. Rehabilitation after traumatic injury (NG211), 2022, https://www.nice.org.uk/guidance/ng21]. While the pathogenesis and pathophysiology of dysphagia in cSCI remains unclear, numerous risk factors have been identified in the literature. This review aims to summarize the literature on the risk factors, presentation, assessment, and management of dysphagia in patients with cSCI. A bespoke approach to dysphagia management, that accounts for the multiple system impairment in cSCI, is presented; the overarching aim of which is to support effective management of dysphagia in patients with cSCI to prevent adverse clinical consequences.

Comparison of Different Tidal Volumes for Ventilation in Patients with an Acute Traumatic Cervical Spine Injury

Background

There is scant literature comparing high tidal volume ventilation (HTV) over low tidal volume (LTV) ventilation in acute traumatic cervical spinal cord injury (CSCI).

Objective

The aim of this prospective randomized controlled parallel-group, single-blinded study was to compare the effect of two different tidal volumes (12-15 mL/kg and 6-8 mL/kg) in CSCI on days to achieve ventilator-free breathing (VFB), PaO2/FIO2 ratio, the incidence of complications, requirement of vasopressor drugs, total duration of hospital stay, and mortality.

Materials and Methods

We enrolled patients with acute high traumatic CSCI admitted to the neurotrauma intensive care unit within 24 h of injury, requiring mechanical ventilation. Participants were randomized to receive either HTV, 12-15 mL/kg (group H) or LTV, 6-8 mL/kg (group L) tidal volume ventilation.

Results and Conclusions

A total of 56 patients, 28 in each group were analyzed. Patient demographics and injury severity were comparable between the groups. VFB was achieved in 23 and 19 patients in groups H and L, respectively. The median number of days required to achieve VFB was 3 (2, 56) and 8 (2, 50) days, P = 0.33; PaO2: FIO2 ratio was 364.0 ± 64 and 321.0 ± 67.0, P = 0.01; the incidence of atelectasis was 25% and 46%, P = 0.16, respectively, in group H and group L. The hemodynamic parameters and the vasopressor requirement were comparable in both groups. There was no barotrauma. The duration of hospital stay (P = 0.2) and mortality (P = 0.2) was comparable in both groups. There was no significant difference in days to achieve ventilator-free breathing with HTV (12-15 mL/kg) ventilation compared to LTV (6-8 mL/kg) ventilation in acute CSCI. The PaO2:FiO2 ratio was higher with the use of 12-15 mL/kg. No difference in mortality and duration of hospital stay was seen in either group.

Tracheostomy Following Anterior Cervical Discectomy and Fusion With Plating in Trauma Patients: Is It Safe?

Objective

This study aimed to evaluate the safety and necessity of tracheostomy after anterior cervical discectomy and fusion (ACDF) with plating, despite the close proximity of the two surgical skin incisions.

Methods

Sixty-three patients with traumatic cervical fractures or spinal cord injury (SCI) who underwent single-level ACDF and plating between January 2014 and June 2019 were included in this study. The patients included 45 men and 18 women, with a mean age of 48.5 years. A retrospective analysis of the patients’ demographic data, level of injury, radiological findings, and neurological status was performed based on the American Spinal Injury Association (ASIA), open tracheostomy, and decannulation rate. Additionally, risk factors necessitating tracheostomy were statistically analyzed.

Results

Eighteen patients (28.5%) required subsequent open tracheostomy. Among them, 11 patients were successfully decannulated, four patients could not be decannulated during the follow-up period, and three patients died of unrelated complications. The median interval from ACDF with plating to open tracheostomy was 9.6 days (range, 5–23 days). On the basis of neurological status, ASIA A and B patients (p<0.001), high signal intensity on T2-weighted-magnetic resonance (MR) images (p=0.001), and major cervical fracture and dislocation were significant risk factors for tracheostomy (p=0.02). No patient showed evidence of significant soft tissue, bony infection, or nonunion during the follow-up period.

Conclusion

Independent tracheostomy did not increase the risk of infection or nonunion despite the close proximity of the two surgical skin incisions.

Spinal cord injury and degenerative cervical myelopathy

Spinal cord injury (SCI) often results in impaired respiratory function. Paresis or paralysis of inspiratory and expiratory muscles can lead to respiratory dysfunction depending on the level and severity of the injury, which can affect the management and care of SCI patients. Respiratory dysfunction after SCI is more severe in high cervical injuries, with vital capacity (VC) being an essential indicator of overall respiratory health. Respiratory complications include hypoventilation, a reduction in surfactant production, mucus plugging, atelectasis, and pneumonia. Respiratory management includes mechanical ventilation and tracheostomy in high cervical SCI, while noninvasive ventilation is more common in patients with lower cervical and thoracic injuries. Mechanical ventilation can negatively impact the function of the diaphragm and weaning should start as soon as possible. Patients can sometimes be weaned from mechanical ventilation with assistance of electrical stimulation of the phrenic nerve or the diaphragm. Respiratory muscle training regimens may also improve patients' inspiratory function following SCI. Despite the critical advances in preventing, diagnosing, and treating respiratory complications, they continue to significantly affect persons living with SCI. Additional studies of interventions to reduce respiratory complications are likely to further decrease the morbidity and mortality associated with these injuries.

Separation from mechanical ventilation and survival after spinal cord injury: a systematic review and meta-analysis

BACKGROUND

Prolonged need for mechanical ventilation greatly impacts life expectancy of patients after spinal cord injury (SCI). Weaning outcomes have never been systematically assessed. In this systematic review and meta-analysis, we aimed to investigate the probability of weaning success, duration of mechanical ventilation, mortality, and their predictors in mechanically ventilated patients with SCI.

METHODS

We searched six databases from inception until August 2021 for randomized-controlled trials and observational studies enrolling adult patients (≥ 16 years) with SCI from any cause requiring mechanical ventilation. Titles and abstracts were screened independently by two reviewers. Full texts of the identified articles were then assessed for eligibility. Data were extracted independently and in duplicate by pairs of authors, using a standardized data collection form. Synthetic results are reported as meta-analytic means and proportions, based on random effects models.

RESULTS

Thirty-nine studies (14,637 patients, mean age 43) were selected. Cervical lesions were predominant (12,717 patients had cervical lesions only, 1843 in association with other levels' lesions). Twenty-five studies were conducted in intensive care units (ICUs), 14 in rehabilitative settings. In ICU, the mean time from injury to hospitalization was 8 h [95% CI 7-9], mean duration of mechanical ventilation 27 days [20-34], probability of weaning success 63% [45-78] and mortality 8% [5-11]. Patients hospitalized in rehabilitation centres had a greater number of high-level lesions (C3 or above), were at 40 days [29-51] from injury and were ventilated for a mean of 97 days [65-128]; 82% [70-90] of them were successfully weaned, while mortality was 1% [0-19].

CONCLUSIONS

Although our study highlights the lack of uniform definition of weaning success, of clear factors associated with weaning outcomes, and of high-level evidence to guide optimal weaning in patients with SCI, it shows that around two-thirds of mechanically ventilated patients can be weaned in ICU after SCI. A substantial gain in weaning success can be obtained during rehabilitation, with additional duration of stay but minimal increase in mortality. The study is registered with PROSPERO (CRD42020156788).

High tidal volume ventilation is associated with ventilator-associated pneumonia in acute cervical spinal cord injury

CONTEXT/OBJECTIVE

Pneumonia is the leading cause of death after acute spinal cord injury (SCI). High tidal volume ventilation (HVtV) is used in SCI rehabilitation centers to overcome hypoventilation while weaning patients from the ventilator. Our objective was to determine if HVtV in the acute post-injury period in SCI patients is associated with lower incidence of ventilator-associated pneumonia (VAP) when compared to patients receiving standard tidal volume ventilation.

DESIGN

Cohort study.

SETTING

Red Duke Trauma Institute, University of Texas Health Science Center at Houston, TX, USA.

PARTICIPANTS

Adult Acute Cervical SCI Patients, 2011-2018.

INTERVENTIONS

HVtV.

OUTCOME MEASURES

VAP, ventilator dependence at discharge, in-hospital mortality.

RESULTS

Of 181 patients, 85 (47%) developed VAP. HVtV was utilized in 22 (12%) patients. Demographics, apart from age, were similar between patients who received HVtV and standard ventilation; patients were younger in the HVtV group. VAP developed in 68% of patients receiving HVtV and in 44% receiving standard tidal volumes (P = 0.06). After adjustment, HVtV was associated with a 1.96 relative risk of VAP development (95% credible interval 1.55-2.17) on Bayesian analysis. These results correlate with a >99% posterior probability that HVtV is associated with increased VAP when compared to standard tidal volumes. HVtV was also associated with increased rates of ventilator dependence.

CONCLUSIONS

While limited by sample size and selection bias, our data revealed an association between HVtV and increased VAP. Further investigation into optimal early ventilation settings is needed for SCI patients, who are at a high risk of VAP.

Diaphragm Pacing and a Model for Respiratory Rehabilitation After Spinal Cord Injury

BACKGROUND AND PURPOSE

Cervical spinal cord injury (CSCI) can cause severe respiratory impairment. Although mechanical ventilation (MV) is a lifesaving standard of care for these patients, it is associated with diaphragm atrophy and dysfunction. Diaphragm pacing (DP) is a strategy now used acutely to promote MV weaning and to combat the associated negative effects. Initial reports indicate that DP also may promote neuromuscular plasticity and lead to improvements in spontaneous diaphragm activation and respiratory function. These outcomes suggest the need for reevaluation of respiratory rehabilitation for patients with CSCI using DP and consideration of new rehabilitation models for these patients and their unique care needs.

SUMMARY OF KEY POINTS

This article discusses the rationale for consideration of DP as a rehabilitative strategy, particularly when used in combination with established respiratory interventions. In addition, a model of respiratory rehabilitation and recovery (RRR) is presented, providing a framework for rehabilitation and consideration of DP as an adjuvant rehabilitation approach. The model promotes goals such as respiratory recovery and independence, and lifelong respiratory health, via interdisciplinary care, respiratory training, quantitative measurement, and use of adjuvant strategies such as DP. Application of the model is demonstrated through a description of an inpatient rehabilitation program that applies model components to patients with CSCI who require DP.

RECOMMENDATIONS FOR CLINICAL PRACTICE

As DP use increases for patients with acute CSCI, so does the need and opportunity to advance rehabilitation approaches for these patients. This perspective article is a critical step in addressing this need and motivating the advancement of rehabilitation strategies for CSCI patients. (See Video Abstract, Supplemental Digital Content, available at: http://links.lww.com/JNPT/A348).

A Novel Pharyngeal Clearance Maneuver for Initial Tracheostomy Tube Cuff Deflation in High Cervical Tetraplegia

Mechanical insufflation-exsufflation, or "cough assist," is a commonly used method of clearing tracheal and pulmonary secretions in patients with respiratory insufficiency secondary to spinal cord injury. This report presents a novel technique termed the pharyngeal clearance maneuver, which uses a modified application of the mechanical insufflation-exsufflation device to mobilize "secretion burden" at the portion of the trachea above the tracheostomy cuff during cuff deflation. Utilization of this strategy may reduce the risk of aspiration, infection, and respiratory compromise for patients with high cervical spinal cord injury in the acute rehabilitation setting. It is of particular benefit for those whose cuffs are being deflated for the first time and who may have large secretion volumes above the cuff. It can be further used as needed before speaking trials and swallow therapies. We anticipate that the pharyngeal clearance maneuver may be used in other populations with impaired cough and need for invasive ventilator support because of ventilator pump failure (eg, spinal muscular atrophy, congenital myopathies, obesity hypoventilation, amyotrophic lateral sclerosis, muscular dystrophy, and acute inflammatory demyelinating polyneuropathy).

Update on critical care for acute spinal cord injury in the setting of polytrauma

Traumatic spinal cord injury (SCI) often occurs in patients with concurrent traumatic injuries in other body systems. These patients with polytrauma pose unique challenges to clinicians. The current review evaluates existing guidelines and updates the evidence for prehospital transport, immobilization, initial resuscitation, critical care, hemodynamic stability, diagnostic imaging, surgical techniques, and timing appropriate for the patient with SCI who has multisystem trauma. Initial management should be systematic, with focus on spinal immobilization, timely transport, and optimizing perfusion to the spinal cord. There is general evidence for the maintenance of mean arterial pressure of > 85 mm Hg during immediate and acute care to optimize neurological outcome; however, the selection of vasopressor type and duration should be judicious, with considerations for level of injury and risks of increased cardiogenic complications in the elderly. Level II recommendations exist for early decompression, and additional time points of neurological assessment within the first 24 hours and during acute care are warranted to determine the temporality of benefits attributable to early surgery. Venous thromboembolism prophylaxis using low-molecular-weight heparin is recommended by current guidelines for SCI. For these patients, titration of tidal volumes is important to balance the association of earlier weaning off the ventilator, with its risk of atelectasis, against the risk for lung damage from mechanical overinflation that can occur with prolonged ventilation. Careful evaluation of infection risk is a priority following multisystem trauma for patients with relative immunosuppression or compromise. Although patients with polytrauma may experience longer rehabilitation courses, long-term neurological recovery is generally comparable to that in patients with isolated SCI after controlling for demographics. Bowel and bladder disorders are common following SCI, significantly reduce quality of life, and constitute a focus of targeted therapies. Emerging biomarkers including glial fibrillary acidic protein, S100β, and microRNAs for traumatic SCIs are presented. Systematic management approaches to minimize sources of secondary injury are discussed, and areas requiring further research, implementation, and validation are identified.

The impact of acute management on the occurrence of medical complications during the specialized spinal cord injury acute hospitalization following motor-complete cervical spinal cord injury

CONTEXT/OBJECTIVE

Determine the impact of early admission and complete perioperative management in a specialized spinal cord injury (SCI) trauma center (SCI-center) on the occurrence of medical complications following tetraplegia.

DESIGN

A retrospective comparative cohort study of prospectively collected data involving 116 individuals was conducted. Group 1 (N=87) was early managed in a SCI-center promptly after the trauma, whereas Group 2 (N=29) was surgically and preoperatively managed in a non-specialized (NS) center before being transferred to the SCI-center. Bivariate comparisons and multivariate logistic regression analyses were used to assess the relationship between the type of acute care facility and the occurrence of medical complications. Length of stay (LOS) in acute care was also compared.

SETTING

Single Level-1 trauma center.

PARTICIPANTS

Individuals with acute traumatic motor-complete cervical SCI.

INTERVENTIONS

Not applicable Outcome measures: The occurrence of complications during the SCI-center stay.

RESULTS

There was a similar rate of complications between the two groups. However, the LOS was greater in Group 2 (p=0.04). High cervical injuries (C1-C4) showed an important tendency to increase the likelihood of developing a complication, while high cervical injuries and increased trauma severity increased the odds of developing respiratory complications.

CONCLUSION

Although complication rates were similar in non-specialized and specialized centers, peri-operative management in a non-specialized center required a longer length of stay. Prompt transfer to a SCI-center may optimize the care trajectory by favoring earlier transfer to rehabilitation.

Risk factors for dysphagia after a spinal cord injury: a systematic review and meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To determine the risk factors predictive of dysphagia after a spinal cord injury (SCI).

SETTING

None.

METHODS

A comprehensive literature search was performed in five scientific databases for English articles that identified risk factors for dysphagia after a SCI in adult (≥19 years) individuals. Data extracted included: author name, year and country of publication, participant demographics, sample size, study design, method of dysphagia diagnosis, and risk factor percentages. Methodological quality of studies was assessed using the Newcastle-Ottawa Scale. For identified risk factors, risk percentages were transformed into risk ratios (RR) with 95% confidence intervals. Quantitative synthesis was performed for risk factors reported in two or more studies using restricted maximum-likelihood estimator random effects models.

RESULTS

Eleven studies met inclusion criteria of which ten studies were of moderate quality (n = 10). Significant risk factors included: age, injury severity, level of injury, presence of tracheostomy, coughing, voice quality, bronchoscopy need, pneumonia, mechanical ventilation, nasogastric tubes, comorbid injury, and a cervical surgery. Results of the quantitative synthesis indicated that the presence of a tracheostomy posed a threefold greater risk of the development of dysphagia (RR: 3.67); while, cervical surgery posed a 1.3 times greater risk of the development of dysphagia (RR: 1.30).

CONCLUSIONS

Knowledge of these risk factors can be a resource for clinicians in the early diagnosis and appropriate medical management of dysphagia post SCI.

Persons With Chronic Spinal Cord Injuries in the Emergency Department: a Review of a Unique Population

BACKGROUND

Persons with spinal cord injuries (SCIs) are frequent utilizers of emergency medical services but are a poorly understood and medically complex population. As the treatment of acute spinal cord injuries improves, there is a growing population of patients suffering from the chronic neurological deficits and altered homeostasis resulting from those injuries.

OBJECTIVES

We sought to highlight the unique diagnostic challenges of treating persons with SCIs and to review ailments uncommon in the general population but often encountered in this population.

DISCUSSION

Spinal cord anatomy is briefly reviewed and commonly used nomenclature and grading scales are defined. An organ by organ review is offered detailing unique clinical issues that pertain to those systems. Practice pearls and pitfall are elucidated when relevant. Psychiatric complications of this disease entity are also discussed.

CONCLUSION

A SCI is a devastating but increasingly survivable event. The long-term care of persons with SCIs is challenging because of the unique pathologies encountered in this population and the disruption of normal and expected physiological responses to common ailments. This review will facilitate a better understanding of the emergency care needs of this unique patient population.

Stimulation of abdominal and upper thoracic muscles with surface electrodes for respiration and cough: Acute studies in adult canines

OBJECTIVE

To optimize maximal respiratory responses with surface stimulation over abdominal and upper thorax muscles and using a 12-Channel Neuroprosthetic Platform.

METHODS

Following instrumentation, six anesthetized adult canines were hyperventilated sufficiently to produce respiratory apnea. Six abdominal tests optimized electrode arrangements and stimulation parameters using bipolar sets of 4.5 cm square electrodes. Tests in the upper thorax optimized electrode locations, and forelimb moment was limited to slight-to-moderate. During combined muscle stimulation tests, the upper thoracic was followed immediately by abdominal stimulation. Finally, a model of glottal closure for cough was conducted with the goal of increased peak expiratory flow.

RESULTS

Optimized stimulation of abdominal muscles included three sets of bilateral surface electrodes located 4.5 cm dorsal to the lateral line and from the 8^th intercostal space to caudal to the 13^th rib, 80 or 100 mA current, and 50 Hz stimulation frequency. The maximal expired volume was 343 ± 23 ml (n=3). Optimized upper thorax stimulation included a single bilateral set of electrodes located over the 2^nd interspace, 60 to 80 mA, and 50 Hz. The maximal inspired volume was 304 ± 54 ml (n=4). Sequential stimulation of the two muscles increased the volume to 600 ± 152 ml (n=2), and the glottal closure maneuver increased the flow.

CONCLUSIONS

Studies in an adult canine model identified optimal surface stimulation methods for upper thorax and abdominal muscles to induce sufficient volumes for ventilation and cough. Further study with this neuroprosthetic platform is warranted.

Mechanical ventilation modulates pro-inflammatory cytokine expression in spinal cord tissue after injury in rats

RATIONALE

Spinal cord injury (SCI) may induce significant respiratory muscle weakness and paralysis, which in turn may cause a patient to require ventilator support. Central nervous system alterations can also exacerbate local inflammatory responses with immune cell infiltration leading to additional risk of inflammation at the injury site. Although mechanical ventilation is the traditional treatment for respiratory insufficiency, evidence has shown that it may directly affect distant organs through systemic inflammation.

OBJECTIVES

This study aimed to better understand the impact of invasive mechanical ventilation on local spinal cord inflammatory responses following cervical or thoracic SCI.

METHODS

Five groups of female Sprague-Dawley rats were anesthetised for 24 h. Three groups received mechanical ventilation: seven rats without SCI, seven rats with cervical injury (C4-C5), and seven rats with thoracic injury (T10); whereas, two groups were non-ventilated: six rats without SCI; and six rats with thoracic injury (T10). Changes in inflammatory responses were determined in the spinal cord tissues collected at the local site of injury. Cytokines were measured using ELISA.

MAIN RESULTS

SCI induced local pro-inflammatory cytokine IL-6 expression for all groups. Mechanical ventilation also had effects on pro-inflammatory cytokines and independently increased TNF-α and decreased IL-1β levels in the spinal cords of anesthetized rats.

CONCLUSION

These data provide the first evidence that mechanical ventilation contributes to local inflammation after SCI and in the absence of direct tissue injury.

The impact of a specialized spinal cord injury center as compared with non-specialized centers on the acute respiratory management of patients with complete tetraplegia: an observational study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To compare the proportion of tracheostomy placement and duration of mechanical ventilation (MV) in patients with a complete cervical spinal cord injury (SCI) that were managed early or lately in a specialized acute SCI-center. The second objective was to determine the impact of the timing of admission to the SCI-center on the MV support duration.

SETTING

A single Level-1 trauma center specialized in SCI care in Quebec (Canada).

METHODS

A cohort of 81 individuals with complete tetraplegia over a 6-years period was included. Group 1 (N = 57- early group-) was admitted before surgical management in one specialized acute SCI-center, whereas Group 2 (N = 24 -late group-) was surgically managed in a non-specialized center and transferred to the SCI-center for post-operative management only. The proportion of tracheostomy placement and MV duration were compared. Multivariate regression analysis was used to assess the impact of the timing of admission to the SCI-center on the MV duration during the SCI-center stay.

RESULTS

Patients in Group 2 had a higher proportion of tracheostomy (70.8 vs. 35.1%, p = 0.004) and a higher mean duration of MV support (68.0 ± 64.2 days vs. 21.8 ± 29.7 days, p = 0.006) despite similar age, trauma severity (ISS), neurological level of injury and proportion of pneumonia. Later transfer to the specialized acute SCI-center was the main predictive factor of longer MV duration, with a strong impact factor (s = 946.7, p < 0.001).

CONCLUSIONS

Early admission to a specialized acute SCI-center for surgical and peri-operative management after a complete tetraplegia is associated with lower occurrence of tracheostomy and shorter mechanical ventilation duration support.

SPONSORSHIP

MENTOR Program of the Canadian Institute of Health Research and US Department of Defense Spinal Cord Injury Research Program.

Supraspinal respiratory plasticity following acute cervical spinal cord injury

Impaired breathing is a devastating result of high cervical spinal cord injuries (SCI) due to partial or full denervation of phrenic motoneurons, which innervate the diaphragm - a primary muscle of respiration. Consequently, people with cervical level injuries often become dependent on assisted ventilation and are susceptible to secondary complications. However, there is mounting evidence for limited spontaneous recovery of respiratory function following injury, demonstrating the neuroplastic potential of respiratory networks. Although many studies have shown such plasticity at the level of the spinal cord, much less is known about the changes occurring at supraspinal levels post-SCI. The goal of this study was to determine functional reorganization of respiratory neurons in the medulla acutely (>4h) following high cervical SCI. Experiments were conducted in decerebrate, unanesthetized, vagus intact and artificially ventilated rats. In this preparation, spontaneous recovery of ipsilateral phrenic nerve activity was observed within 4 to 6h following an incomplete, C2 hemisection (C2Hx). Electrophysiological mapping of the ventrolateral medulla showed a reorganization of inspiratory and expiratory sites ipsilateral to injury. These changes included i) decreased respiratory activity within the caudal ventral respiratory group (cVRG; location of bulbospinal expiratory neurons); ii) increased proportion of expiratory phase activity within the rostral ventral respiratory group (rVRG; location of inspiratory bulbo-spinal neurons); iii) increased respiratory activity within ventral reticular nuclei, including lateral reticular (LRN) and paragigantocellular (LPGi) nuclei. We conclude that disruption of descending and ascending connections between the medulla and spinal cord leads to immediate functional reorganization within the supraspinal respiratory network, including neurons within the ventral respiratory column and adjacent reticular nuclei.

Pulmonary outcomes following specialized respiratory management for acute cervical spinal cord injury: a retrospective analysis

Study Design

Retrospective analysis.

Objectives

To identify multivariate interactions of respiratory function that are sensitive to spinal cord injury level and pharmacological treatment to promote strategies that increases successful liberation from mechanical ventilation.

Setting

United States regional spinal cord injury (SCI) treatment center.

Methods

Retrospective chart review of patients consecutively admitted to Santa Clara Valley Medical Center (SCVMC) between May 2013 and December 2014 for ventilator weaning with C1-5 AIS A or B SCI, < 3 months from injury and who had a tracheostomy in place. A non-linear, categorical principal component analysis (NL-PCA) was performed to test the multivariate interaction of respiratory outcomes from patients (N=36) being weaned off ventilator support after acute SCI with (N=15) or without (N=21) theophylline treatment.

Results

36 patients met inclusion criteria (2 C1, 5 C2, 11 C3, 14 C4, 4 C5). The NL-PCA returned 3 independent components that accounted for 95% of the variance in the dataset. Multivariate general linear models (GLM) hypothesis tests revealed a significant syndromic interaction between theophylline treatment and SCI level (Wilks’ Lambda, p=0.028, F(12,64)=2.116, η2=0.256, 1−β=0.838), with post-hoc testing demonstrating a significant interaction on PC1, explained by a positive correlation between improved forced vital capacity and time it took to reach 16 hours of ventilator free breathing. Thirty-three patients (92%) achieved 16 hours ventilator-free breathing (VFB), 30 (83%) achieved 24 hours VFB.

Conclusions

We suspect that some portion of the high success rate of ventilator weaning may be attributable to theophylline use in higher cervical SCI; in addition to our aggressive regimen of high volume ventilation, medication optimization, and pulmonary toilet (positive pressure treatments and mechanical insufflation-exsufflation).

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.

Intrapulmonary Percussive Ventilation as a Lung Recruitment Strategy in Brain-Dead Organ Donors

OBJECTIVE

To determine the strength of the evidence evaluating the effectiveness of intrapulmonary percussive ventilation (IPV) as a safe alternative or adjunctive therapy to traditional chest physiotherapy (CPT) among potential organ donors.

DATA SOURCES

Literature search conducted from February 2015 to November 2015 using PubMed, Cumulative Index of Nursing and Allied Health Literature, Scopus, and bibliographies of pertinent articles. Search Terms: Intrapulmonary percussive ventilation, chest physiotherapy, chest wall oscillation, organ donors, and ventilation.

STUDY SELECTION

Articles in English from 1994 to present directly compared IPV to CPT or conventional (no) therapy.

DATA EXTRACTION

Association of Critical-Care Nurses Levels of Evidence was used to determine the strength of evidence. Level B and level C articles were reviewed.

DATA SYNTHESIS

No studies were found using IPV in the donor population. Results from studies using IPV in other populations indicated IPV had no adverse effects, improved sputum clearance and oxygenation, and reduced atelectasis and pneumonia in patients with artificial airways.

CONCLUSION

Intrapulmonary percussive ventilation may be a safe and effective alternative or adjunctive to CPT therapy and improve the number of lungs available for transplantation. Clinical research is essential to determine the effectiveness of this therapy for lung recruitment in the donor population.

Ventilatory Management of the Noninjured Lung

This article reviews aspects of mechanical ventilation in patients without lung injury, patients in the perioperative period, and those with neurologic injury or disease including spinal cord injury. Specific emphasis is placed on ventilator strategies, including timing and indications for tracheostomy. Lung protective ventilation, using low tidal volumes and modest levels of positive end-expiratory pressure, should be the default consideration in all patients requiring mechanical ventilatory support. The exception may be the patient with high cervical spinal cord injuries who requires mechanical ventilatory support. There is no consensus on the timing of tracheostomy in patients with neurologic diseases.

Mortality and longevity after a spinal cord injury: systematic review and meta-analysis

BACKGROUND/AIMS

Mortality and longevity studies of spinal cord injury (SCI) are essential for informing healthcare systems and policies. This review evaluates the current evidence among people with SCIs worldwide in relation to the WHO region and country income level; demographic and lesion characteristics; and in comparison with the general population.

METHODS

A systematic review of relevant databases for original studies. Pooled estimates were derived using random effects meta-analysis, restricted to traumatic SCI.

RESULTS

Seventy-four studies were included. In-hospital mortality varied, with pooled estimates of 24.1% (95% confidence interval (CI) 14.1-38.0), 7.6% (95% CI 6.3-9.0), 7.0% (95% CI 1.5-27.4), and 2.1% (95% CI 0.9-5.0) in the WHO regions of Africa, the Americas, Europe and Western Pacific. The combined estimate for low- and middle-income countries was nearly three times higher than for high-income countries. Pooled estimates of first-year survival were 86.5% (95% CI 75.3-93.1), 95.6% (95% CI 81.0-99.1), and 94.0% (95% CI 93.3-94.6) in the Americas, Europe and Western Pacific. Pooled estimates of standardized mortality ratios in tetraplegics were 2.53 (2.00-3.21) and 2.07 (1.47-2.92) in paraplegics.

CONCLUSION

This study found substantial variation in mortality and longevity within the SCI population, compared to the general population, and between WHO regions and country income level. Improved standardization and quality of reporting is needed to improve inferences regarding the extent to which mortality outcomes following an SCI are related to healthcare systems, services and policies.

An intermediate respiratory care unit for spinal cord-injured patients. A retrospective study

OBJECTIVES

Patients with cervical spinal cord injury (SCI) may need prolonged mechanical ventilation (MV) and a long stay in the Intensive Care Unit. An intermediate respiratory care unit (IRCU) can shorten that stay, optimizing hospital resources. The aim of our work has been to evaluate the activity of such a unit in our hospital.

METHODS

This is a descriptive retrospective study based on the data of patients with SCI and respiratory failure discharged from our IRCU between 1 July 2010 and 28 February 2013.

RESULTS

We have analysed data from 146 patients with SCI, adding up to 228 admissions (68 first admissions and 160 readmissions due to complications or scheduled review visits). Sixty-three out of the 68 newly admitted patients survived their first admission (92.6%). Length of hospitalization was 195.6±110.4 days, 22 were admitted to monitor their respiratory status and 46 were on MV on admission. Of these, 26 (38.2%) were admitted to attempt weaning from the respirator and 20 (29.4%) to enter a programme of permanent respiratory support. Weaning was successful in 23 out of 26 patients (88.4%), the process taking 47.2±49.3 days. Forty of them (58.8%) were discharged to their home.

CONCLUSIONS

An IRCU can manage a substantial number of severe SCI patients who need MV, and an important number of them can be weaned from the respirator. It may also achieve a good success rate in the integration of MV-dependent patients within family and society.

Pulmonary management of the acute cervical spinal cord injured patients

A traumatic spinal cord injury is a catastrophic event associated with physiologic disruptions to the motor, sensory, cardiovascular, and respiratory systems. Respiratory complications are a common cause of morbidity and mortality in patients with acute cervical spinal cord injury and treatments must be initiated immediately. The longer it takes for a patient to receive pulmonary treatments and mobility activities, the higher the morbidity and mortality and the longer the length of stay. Disrupted pulmonary mechanics and respiratory complications are frequent and are influenced by the level of injury.

Respiratory management in the patient with spinal cord injury

Spinal cord injuries (SCIs) often lead to impairment of the respiratory system and, consequently, restrictive respiratory changes. Paresis or paralysis of the respiratory muscles can lead to respiratory insufficiency, which is dependent on the level and completeness of the injury. Respiratory complications include hypoventilation, a reduction in surfactant production, mucus plugging, atelectasis, and pneumonia. Vital capacity (VC) is an indicator of overall pulmonary function; patients with severely impaired VC may require assisted ventilation. It is best to proceed with intubation under controlled circumstances rather than waiting until the condition becomes an emergency. Mechanical ventilation can adversely affect the structure and function of the diaphragm. Early tracheostomy following short orotracheal intubation is probably beneficial in selected patients. Weaning should start as soon as possible, and the best modality is progressive ventilator-free breathing (PVFB). Appropriate candidates can sometimes be freed from mechanical ventilation by electrical stimulation. Respiratory muscle training regimens may improve patients' inspiratory function following a SCI.