Noninvasive respiratory management of high level spinal cord injury

Coordination Between Respiration and Swallowing in Patients With Dysphagia After Cervical Spinal Cord Injury: An Observational Case-Control Study

PURPOSE

The purpose of the present study was to characterize the differences between respiration and swallowing in patients with dysphagia after cervical spinal cord injury (CSCI) and to explore the underlying physiological changes.

METHOD

A total of 95 participants were recruited for bedside swallowing evaluation followed by a flexible endoscopic evaluation of swallowing and surface electromyography with a thermocouple nasal airflow sensor examination: 32 with dysphagia, 33 without dysphagia, and 30 healthy controls. The differences in respiratory patterns, swallowing apnea duration (SAD), inspiratory-expiratory ratio, and swallowing efficiency were observed among healthy adults, CSCI patients with and without dysphagia after CSCI.

RESULTS

Compared with those of healthy controls and patients without dysphagia after CSCI, the postswallow respiratory pattern of patients with dysphagia after CSCI was an inspiratory pattern, and the SAD was significantly shorter in patients with dysphagia after CSCI (p < .001). Additionally, the expiratory time in patients with dysphagia was significantly shorter than the inspiratory time, and the swallowing efficiency was reduced, requiring multiple swallows. Moreover, the index of SAD was statistically significant for predicting the development of dysphagia in patients with CSCI (p < .001).

CONCLUSION

Patients with CSCI have an inspiratory pattern after swallowing, and the SAD is significantly reduced; SAD can be used as the predictor of dysphagia in patients after CSCI; the pattern of coordination between respiration and swallowing in patients with dysphagia after CSCI is different from that of healthy controls and patients without dysphagia after CSCI.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26524717.

Metformin alleviates spinal cord injury by inhibiting nerve cell ferroptosis through upregulation of heme oxygenase-1 expression

JOURNAL/nrgr/04.03/01300535-202409000-00037/figure1/v/2024-01-16T170235Z/r/image-tiff Previous studies have reported upregulation of heme oxygenase-1 in different central nervous system injury models. Heme oxygenase-1 plays a critical anti-inflammatory role and is essential for regulating cellular redox homeostasis. Metformin is a classic drug used to treat type 2 diabetes that can inhibit ferroptosis. Previous studies have shown that, when used to treat cardiovascular and digestive system diseases, metformin can also upregulate heme oxygenase-1 expression. Therefore, we hypothesized that heme oxygenase-1 plays a significant role in mediating the beneficial effects of metformin on neuronal ferroptosis after spinal cord injury. To test this, we first performed a bioinformatics analysis based on the GEO database and found that heme oxygenase-1 was upregulated in the lesion of rats with spinal cord injury. Next, we confirmed this finding in a rat model of T9 spinal cord compression injury that exhibited spinal cord nerve cell ferroptosis. Continuous intraperitoneal injection of metformin for 14 days was found to both upregulate heme oxygenase-1 expression and reduce neuronal ferroptosis in rats with spinal cord injury. Subsequently, we used a lentivirus vector to knock down heme oxygenase-1 expression in the spinal cord, and found that this significantly reduced the effect of metformin on ferroptosis after spinal cord injury. Taken together, these findings suggest that metformin inhibits neuronal ferroptosis after spinal cord injury, and that this effect is partially dependent on upregulation of heme oxygenase-1.

Effects of mechanical insufflation-exsufflation on ventilator-free days in intensive care unit subjects with sputum retention; a randomized clinical trial

BACKGROUND

Mechanical insufflation-exsufflation (MI-E) facilitates extubation. However, its potential to reduce the duration of ventilator use remains unclear. Therefore, the present study investigated whether the use of MI-E shortened the duration of mechanical ventilation in patients with high sputum retention.

METHODS

A randomized open-label trial was conducted at a single intensive care unit (ICU) in Japan between November 2017 and June 2019. Ventilated subjects requiring suctioning at least once every hour due to sputum retention were randomly assigned to the MI-E group or conventional care group. The primary endpoint was the number of ventilator-free days on day 28. Secondary endpoints were ventilator days in surviving subjects, the length of ICU stay, and mortality and tracheostomy rates among survivors.

RESULTS

Forty-eight subjects (81% males) with a median age of 72 years (interquartile range [IQR], 65-85 years) were enrolled. There were 27 subjects in the MI-E group and 21 in the control group. The median number of ventilator-free days was 21 (IQR, 13-24) and 18, respectively (IQR, 0-23) (P = .38). No significant differences were observed in the ICU length of stay (median, 10 days (IQR, 7-12) vs 12 days (IQR, 6-15); P = .31), mortality rate (19% vs 15%; odds ratio [OR], 1.36 [0.28-6.50]; P = .69), or tracheostomy rate among survivors (14% vs 28%; OR, 0.40 [0.08-1.91]; P = .25).

CONCLUSION

In ventilated subjects in the ICU with high sputum retention, the use of MI-E did not significantly increase the number of ventilator-free days over that with conventional care.

Spinal cord injury: global burden from 1990 to 2019 and projections up to 2030 using Bayesian age-period-cohort analysis

Background

Spinal cord injuries, often resulting from spine fractures, can lead to severe lifelong symptoms such as paraplegia and even mortality. Over the past few decades, there has been a concerning increase in the annual incidence and mortality rates of spinal cord injuries, which has also placed a growing financial strain on healthcare systems. This review aims to offer a comprehensive overview of spinal cord injuries by estimating their global incidence, prevalence, and the impact in terms of years lived with disability, using data obtained from the 2019 Global Burden of Disease Study.

Method

In this study, we utilized data from the 2019 Global Burden of Disease Study, a widely recognized source for global health data. Our methodology involved estimating the global incidence and prevalence of spinal cord injuries while also assessing the impact on years lived with a disability. We analyzed this data comprehensively to identify patterns and trends and made predictions.

Finding

This research delved into the evolving trends in the global burden of spinal cord injuries, identified key risk factors, and examined variations in incidence and disability across different Socio-demographic Index (SDI) levels and age groups. Briefly, in 2019, the global incidence and burden of YLDs of SCI significantly increased compared to 1990. While males had higher incidence rates compared to females. Falls were identified as the primary cause of SCI. Trend projections up to 2030 revealed a slight decrease in ASIR for males, an upward trend in age-specific incidence rates for both sexes and a similar pattern in age-standardized YLD rates. Additionally, our findings provided crucial groundwork for shaping future policies and healthcare initiatives, with the goal of mitigating the burden of spinal cord injuries, enhancing patient outcomes, and fortifying prevention efforts.

Interpretation

Understanding the global burden of spinal cord injuries is essential for designing effective healthcare policies and prevention strategies. With the alarming increase in prevalence rates and their significant impact on individuals and healthcare systems, this research contributes vital insights to guide future efforts in reducing the incidence of spinal cord injuries, improving the quality of life for affected individuals, and reducing the economic burden on healthcare systems worldwide.

Ventilatory Strategies in Traumatic Cervical Spinal Cord Injury: Controversies and Current Updates

Ventilatory management of patients with traumatic cervical spinal cord injury (CSCI) is a complex and controversial area of critical care medicine. Despite significant advances in our understanding of the pathophysiology of CSCI and the development of novel interventions, there remains a lack of consensus about the optimal approach to ventilatory management in these patients. Some of the key controversies in CSCI ventilatory management include timing of tracheal intubation, non-invasive ventilation versus invasive ventilation, high versus low tidal volume, and early versus late tracheostomy. The objective of this review is to discuss the existing controversies and provide an insight on the current evidence.

Successful decannulation of patients with traumatic spinal cord injury: A scoping review

Context: Patients with spinal cord injury (SCI) often require tracheostomy as an immediate life-saving measure. Successful decannulation, or removal of the tracheostomy, improves patient quality of life, function, and physical appearance and is considered an important rehabilitative milestone for SCI patients.Objective: We sought to synthesize the existing published literature on SCI patients undergoing decannulation.Methods: Ovid MEDLINE, Embase, Web of Science, CINAHL, and Cochrane Central Register of Controlled Trials were systematically searched through July 2, 2019 using appropriate keywords and MeSH terms pertaining to tracheostomy and SCI. Searches were human-subject only without language restrictions. Published literature discussing the outcomes of SCI patients who underwent decannulation were screened using inclusion/exclusion criteria determined a priori and reviewed.Results: Twenty-six publications were eligible for review and synthesis out of 1,493 unique articles. Over half of the studies were retrospective case series or reports. The research was nearly all published within the fields of physical medicine and rehabilitation, neurology, and pulmonary/critical care. Three themes emerged from review: (1) interdisciplinary or multidisciplinary tracheostomy team management to optimize decannulation processes, (2) non-invasive intermittent positive-pressure ventilatory support instead of tracheostomy-based ventilator support, and (3) wide variation in the reporting of post-decannulation clinical outcomes.Conclusion: Published research lacks a consistent taxonomy for reporting post-decannulation outcomes in SCI patients. Non-invasive ventilation research could benefit many SCI patients but has been studied in depth primarily by a single authorship group. Further investigation into the socioeconomic and fiscal impact on tracheostomies on SCI patients is warranted.

Effective Mechanical Insufflation-Exsufflation in a Patient With Difficulty in Sputum Discharge and Intensive Care Unit-Acquired Weakness: A Case Report

Intensive care unit-acquired weakness (ICU-AW), a common complication in critically ill patients, may result in diaphragmatic dysfunction, which delays weaning from artificial ventilators. Here, we present the case of a patient with difficulty in sputum discharge due to ICU-AW. In the ICU, postural drainage sputum aspiration by bronchoscopy and squeezing were performed daily, but the patient’s condition did not resolve. Mechanical insufflation-exsufflation (MI-E) enabled the sputum to move to the main bronchus from the peripheral bronchi, and suctioning using a bronchoscope was no longer necessary. However, the presence of sputum persisted, and MI-E was necessary after weaning, proving crucial in treating the patient with sputum discharge difficulty complicated by ICU-AW after being removed from an artificial ventilator. MI-E can be useful for patients with difficulty in sputum discharge due to ICU-AW; however, the weaning process may be prolonged in such cases.

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.

Perioperative management of spinal cord injury: the anesthesiologist's point of view

BACKGROUND

Traumatic spinal cord injury (SCI) is one of the most devastating events a person can experience. It may be life-threatening or result in long-term disability. This narrative review aims to delineate a systematic step-wise airways, breathing, circulation and disability (ABCD) approach to perioperative patient management during spinal cord surgery in order to fill some of the gaps in our current knowledge.

METHODS

We performed a comprehensive review of the literature regarding the perioperative management of traumatic spinal injuries from May 15, 2020, to December 13, 2020. We consulted the PubMed and Embase database libraries.

RESULTS

Videolaryngoscopy supplements the armamentarium available for airway management. Optical fiberscope use should be evaluated when intubating awake patients. Respiratory complications are frequent in the acute phase of traumatic spinal injury, with an estimated incidence of 36-83%. Early tracheostomy can be considered for expected difficult weaning from mechanical ventilation. Careful intraoperative management of administered fluids should be pursued to avoid complications from volume overload. Neuromonitoring requires investments in staff training and cooperation, but better outcomes have been obtained in centers where it is routinely applied. The prone position can cause rare but devastating complications, such as ischemic optic neuropathy; thus, the anesthetist should take the utmost care in positioning the patient.

CONCLUSIONS

A one-size fit all approach to spinal surgery patients is not applicable due to patient heterogeneity and the complexity of the procedures involved. The neurologic outcome of spinal surgery can be improved, and the incidence of complications reduced with better knowledge of patient-specific aspects and individualized perioperative management.

Diaphragm pacing improves respiratory mechanics in acute cervical spinal cord injury

BACKGROUND

Cervical spinal cord injury (CSCI) is devastating with ventilator-associated pneumonia being a main driver of morbidity and mortality. Laparoscopic diaphragm pacing implantation (DPS) has been used for earlier liberation from mechanical ventilation. We hypothesized that DPS would improve respiratory mechanics and facilitate liberation.

METHODS

We performed a retrospective review of acute CSCI patients between January 2005 and May 2017. Routine demographics were collected. Patients underwent propensity score matching based on age, Injury Severity Score, ventilator days, hospital length of stay, and need for tracheostomy. Patients with complete respiratory mechanics data were analyzed and compared. Those who did not have DPS (NO DPS) had spontaneous tidal volume (Vt) recorded at time of intensive care unit admission, at day 7, and at day 14, and patients who had DPS had spontaneous Vt recorded before and after DPS. Time to ventilator liberation and changes in size of spontaneous Vt for patients while on the ventilator were analyzed. Bivariate and multivariate logistic and linear regression statistics were performed using STATA v10.

RESULTS

Between July 2011 and May 2017, 37 patients that had DPS were matched to 34 who did not (NO DPS). Following DPS, there was a statistically significant increase in spontaneous Vt compared with NO DPS (+88 mL vs. -13 mL; 95% confidence interval, 46-131 mL vs. -78 to 51 mL, respectively; p = 0.004). Median time to liberation after DPS was significantly shorter (10 days vs. 29 days; 95% CI, 6.5-13.6 days vs. 23.1-35.3 days; p < 0.001). Liberation prior to hospital discharge was not different between the two groups. The DPS placement was found to be associated with a statistically significant decrease in days to liberation and an increase in spontaneous Vt in multivariate linear regression models.

CONCLUSION

The DPS implantation in acute CSCI patients produces significant improvements in spontaneous Vt and reduces time to liberation from mechanical ventilation. Prospective comparative studies are needed to define the clinical benefits and potential cost savings of DPS implantation.

LEVEL OF EVIDENCE

Therapeutic IV.

Long-Term Non-invasive Ventilation in Children: Current Use, Indications, and Contraindications

This review focuses on the delivery of non-invasive ventilation-i.e., intermittent positive-pressure ventilation-in children lasting more than 3 months. Several recent reviews have brought to light a dramatic escalation in the use of long-term non-invasive ventilation in children over the last 30 years. This is due both to the growing number of children receiving care for complex and severe diseases necessitating respiratory support and to the availability of LT-NIV equipment that can be used at home. While significant gaps in availability persist for smaller children and especially infants, home LT-NIV for children with chronic respiratory insufficiency has improved their quality of life and decreased the overall cost of care. While long-term NIV is usually delivered during sleep, it can also be delivered 24 h a day in selected patients. Close collaboration between the hospital complex-care team, the home LT-NIV program, and family caregivers is of the utmost importance for successful home LT-NIV. Long-term NIV is indicated for respiratory disorders responsible for chronic alveolar hypoventilation, with the aim to increase life expectancy and maximize quality of life. LT-NIV is considered for conditions that affect respiratory-muscle performance (alterations in central respiratory drive or neuromuscular function) and/or impose an excessive respiratory load (airway obstruction, lung disease, or chest-wall anomalies). Relative contraindications for LT-NIV include the inability of the local medical infrastructure to support home LT-NIV and poor motivation or inability of the patient/caregivers to cooperate or understand recommendations. Anatomic abnormalities that interfere with interface fitting, inability to protect the lower airways due to excessive airway secretions and/or severely impaired swallowing, or failure of LT-NIV to support respiration can lead to considering invasive ventilation via tracheostomy. Of note, providing home LT-NIV during the COVID 19 pandemic has become more challenging. This is due both to the disruption of medical systems and the fear of contaminating care providers and family with aerosols generated by a patient positive for SARS-CoV-2 during NIV. Delay in initiating LT-NIV, decreased frequency of home visits by the home ventilation program, and decreased availability of polysomnography and oximetry/transcutaneous PCO2 monitoring are observed. Teleconsultations and telemonitoring are being developed to mitigate these challenges.

Noninvasive Ventilation and Spinal Cord Injury

Individuals with spinal cord injury (SCI) are at increased risk of respiratory complications during wake and sleep. Sleep-disordered breathing (SDB) is commonly associated with SCI and requires an individualized approach to its management. Respiratory control plays a key role in the pathogenesis of SDB in cervical SCI. Noninvasive ventilation plays an important role in the management of respiratory complications in individuals with SCI acutely and in chronic phases. Positive airway pressure treatment may be effective in eliminating SDB and improving sleepiness symptoms, but adherence to treatment is poor and effect on long-term outcomes is questionable.

Use of diaphragm pacing in the management of acute cervical spinal cord injury

BACKGROUND

Cervical spinal cord injury (CSCI) is devastating. Respiratory failure, ventilator-associated pneumonia (VAP), sepsis, and death frequently occur. Case reports of diaphragm pacing system (DPS) have suggested earlier liberation from mechanical ventilation in acute CSCI patients. We hypothesized DPS implantation would decrease VAP and facilitate liberation from ventilation.

METHODS

We performed a retrospective review of patients with acute CSCI managed at a single Level 1 trauma center between January 2005 and May 2017. Routine demographics were collected. Patients underwent propensity matching based on age, injury severity score, ventilator days, hospital length of stay, and need for tracheostomy. Outcome measures included hospital length of stay, intensive care unit length of stay, ventilator days (vent days), incidence of VAP, and mortality. Bivariate and multivariate logistic and linear regression statistics were performed using STATA Version 10.

RESULTS

Between July 2011 and May 2017, all patients with acute CSCI were evaluated for DPS implantation. Forty patients who had laparoscopic DPS implantation (DPS) were matched to 61 who did not (NO DPS). Median time to liberation after DPS implantation was 7 days. Hospital length of stay and mortality were significantly lower on bivariate analysis in DPS patients. Diaphragm pacing system placement was not found to be associated with statistically significant differences in these outcomes on risk-adjusted multivariate models that included admission year.

CONCLUSIONS

Diaphragm pacing system implantation in patients with acute CSCI can be one part of a comprehensive critical care program to improve outcomes. However, the association of DPS with the marked improved mortality seen on bivariate analysis may be due solely to improvements in critical care throughout the study period. Further studies to define the benefits of DPS implantation are needed.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Experiences of Speaking With Noninvasive Positive Pressure Ventilation: A Qualitative Investigation

Purpose The aim of this study was to describe experiences of speaking with 2 forms of noninvasive positive pressure ventilation (NPPV)-mouthpiece NPPV (M-NPPV) and nasal bilevel positive airway pressure (BPAP)-in people with neuromuscular disorders who depend on NPPV for survival. Method Twelve participants (ages 22-68 years; 10 men, 2 women) with neuromuscular disorders (9 Duchenne muscular dystrophy, 1 Becker muscular dystrophy, 1 postpolio syndrome, and 1 spinal cord injury) took part in semistructured interviews about their speech. All subjects used M-NPPV during the day, and all but 1 used BPAP at night for their ventilation needs. Interviews were audio-recorded, transcribed, and verified. A qualitative descriptive phenomenological approach was used to code and develop themes. Results Three major themes emerged from the interview data: (a) M-NPPV aids speaking (by increasing loudness, utterance duration, clarity, and speaking endurance), (b) M-NPPV interferes with the flow of speaking (due to the need to pause to take a breath, problems with mouthpiece placement, and difficulty in using speech recognition software), and (c) nasal BPAP interferes with speaking (by causing abnormal nasal resonance, muffled speech, mask discomfort, and difficulty in coordinating speaking with ventilator-delivered inspirations). Conclusion These qualitative data from chronic NPPV users suggest that both M-NPPV and nasal BPAP may interfere with speaking but that speech is usually better and speaking is usually easier with M-NPPV. These findings can be explained primarily by the nature of the 2 ventilator delivery systems and their interfaces.

Pathophysiology of Neuromuscular Respiratory Diseases

Gas exchange between the atmosphere and the human body depends on the lungs and the function of the respiratory pump. The respiratory pump consists of the respiratory control center located in the brain, bony rib cage, diaphragm, and intercostal, accessory, and abdominal muscles. A variety of muscles serve to fine-tune adjustments of ventilation to metabolic demands. Appropriate evaluation and interventions can prevent respiratory complications and prolong life in individuals with neuromuscular diseases. This article discusses normal function of the respiratory pump, general pathophysiologic issues, and abnormalities in more common neuromuscular diseases.

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.

Novas perspectivas de fisioterapia respiratória em lesão medular - uma revisão sistemática

Resumo Objetivo: Descrever e analisar parâmetros e efeitos da estimulação elétrica de superfície na função muscular respiratória de pessoas com lesão medular, sobretudo durante a tosse. Métodos: Foi realizada uma revisão sistemática da literatura, com base no Preferred Reporting items for Systematic Reviews and Meta-Analyses. A busca foi realizada nas bases de dados PubMed, PEDro e LILACS, por meio dos seguintes descritores: “estimulação elétrica funcional”, “eletroestimulação, estimulação elétrica”, “tosse”, “higiene brônquica”, “quadriplegia”, “lesão medular espinhal”, “tetraplegia” e “sujeito com tetraplegia” - em espanhol, inglês e português, sem restrição quanto ao ano de publicação. Foram incluídos artigos com amostra de indivíduos com lesão medular assistidos por estimulação elétrica com desfecho relacionado ao sistema respiratório, e foram excluídos artigos com ensaios invasivos de estímulo a tosse. Resultados: Os 12 artigos incluídos revelam heterogeneidade nos protocolos de eletroestimulação da função expiratória, que podem incluir frequências de 30 a 50 Hz, com pulsos de 25 a 400 μs, aplicada por até oito eletrodos distribuídos pelos músculos expiratórios e acessórios. O tempo de aplicação também foi variável e a amplitude de corrente frequentemente estimada pela percepção do paciente, podendo chegar a valores superiores a 100mA. Conclusão: Apesar de não ser possível estabelecer parâmetros rigorosos de fisioterapia por meio da estimulação elétrica, pela escassez e qualidade de estudos que comparem sistematicamente parâmetros de estimulação em subgrupos, foram observadas alterações positivas nas variáveis de função muscular respiratória avaliadas, como o pico de fluxo expiratório e de tosse, em pessoas com lesão medular cervical e torácica.

Noninvasive Respiratory Management of Patients With Neuromuscular Disease

This review article describes definitive noninvasive respiratory management of respiratory muscle dysfunction to eliminate need to resort to tracheotomy. In 2010 clinicians from 22 centers in 18 countries reported 1,623 spinal muscular atrophy type 1 (SMA1), Duchenne muscular dystrophy (DMD), and amyotrophic lateral sclerosis users of noninvasive ventilatory support (NVS) of whom 760 required it continuously (CNVS). The CNVS sustained their lives by over 3,000 patient-years without resort to indwelling tracheostomy tubes. These centers have now extubated at least 74 consecutive ventilator unweanable patients with DMD, over 95% of CNVS-dependent patients with SMA1, and hundreds of others with advanced neuromuscular disorders (NMDs) without resort to tracheotomy. Two centers reported a 99% success rate at extubating 258 ventilator unweanable patients without resort to tracheotomy. Patients with myopathic or lower motor neuron disorders can be managed noninvasively by up to CNVS, indefinitely, despite having little or no measurable vital capacity, with the use of physical medicine respiratory muscle aids. Ventilator-dependent patients can be decannulated of their tracheostomy tubes.

Mouthpiece ventilation and complementary techniques in patients with neuromuscular disease: A brief clinical review and update

Noninvasive ventilatory support (NVS) is sometimes reported as suboptimal in patients with neuromuscular disease (NMD). The reasons for this include inadequate ventilator settings and/or lack of interface tolerance. NVS has been used for many years in patients with NMD disorders as a viable alternative to continuous ventilatory support via a tracheostomy tube. The mouthpiece ventilation (MPV) is a ventilatory mode that is used as daytime ventilatory support in combination with other ventilatory modalities and interfaces for nocturnal NVS. However, there is still a poor understanding of this method's benefits compared with other modalities. This review aims to highlight the indications and advantages along with the disadvantages of MPV.

Cough augmentation techniques for extubation or weaning critically ill patients from mechanical ventilation

BACKGROUND

There are various reasons why weaning and extubation failure occur, but ineffective cough and secretion retention can play a significant role. Cough augmentation techniques, such as lung volume recruitment or manually- and mechanically-assisted cough, are used to prevent and manage respiratory complications associated with chronic conditions, particularly neuromuscular disease, and may improve short- and long-term outcomes for people with acute respiratory failure. However, the role of cough augmentation to facilitate extubation and prevent post-extubation respiratory failure is unclear.

OBJECTIVES

Our primary objective was to determine extubation success using cough augmentation techniques compared to no cough augmentation for critically-ill adults and children with acute respiratory failure admitted to a high-intensity care setting capable of managing mechanically-ventilated people (such as an intensive care unit, specialized weaning centre, respiratory intermediate care unit, or high-dependency unit).Secondary objectives were to determine the effect of cough augmentation techniques on reintubation, weaning success, mechanical ventilation and weaning duration, length of stay (high-intensity care setting and hospital), pneumonia, tracheostomy placement and tracheostomy decannulation, and mortality (high-intensity care setting, hospital, and after hospital discharge). We evaluated harms associated with use of cough augmentation techniques when applied via an artificial airway (or non-invasive mask once extubated/decannulated), including haemodynamic compromise, arrhythmias, pneumothorax, haemoptysis, and mucus plugging requiring airway change and the type of person (such as those with neuromuscular disorders or weakness and spinal cord injury) for whom these techniques may be efficacious.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 4, 2016), MEDLINE (OvidSP) (1946 to April 2016), Embase (OvidSP) (1980 to April 2016), CINAHL (EBSCOhost) (1982 to April 2016), and ISI Web of Science and Conference Proceedings. We searched the PROSPERO and Joanna Briggs Institute databases, websites of relevant professional societies, and conference abstracts from five professional society annual congresses (2011 to 2015). We did not impose language or other restrictions. We performed a citation search using PubMed and examined reference lists of relevant studies and reviews. We contacted corresponding authors for details of additional published or unpublished work. We searched for unpublished studies and ongoing trials on the International Clinical Trials Registry Platform (apps.who.int/trialsearch) (April 2016).

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials that evaluated cough augmentation compared to a control group without this intervention. We included non-randomized studies for assessment of harms. We included studies of adults and of children aged four weeks or older, receiving invasive mechanical ventilation in a high-intensity care setting.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts identified by our search methods. Two review authors independently evaluated full-text versions, independently extracted data and assessed risks of bias.

MAIN RESULTS

We screened 2686 citations and included two trials enrolling 95 participants and one cohort study enrolling 17 participants. We assessed one randomized controlled trial as being at unclear risk of bias, and the other at high risk of bias; we assessed the non-randomized study as being at high risk of bias. We were unable to pool data due to the small number of studies meeting our inclusion criteria and therefore present narrative results rather than meta-analyses. One trial of 75 participants reported that extubation success (defined as no need for reintubation within 48 hours) was higher in the mechanical insufflation-exsufflation (MI-E) group (82.9% versus 52.5%, P < 0.05) (risk ratio (RR) 1.58, 95% confidence interval (CI) 1.13 to 2.20, very low-quality evidence). No study reported weaning success or reintubation as distinct from extubation success. One trial reported a statistically significant reduction in mechanical ventilation duration favouring MI-E (mean difference -6.1 days, 95% CI -8.4 to -3.8, very low-quality evidence). One trial reported mortality, with no participant dying in either study group. Adverse events (reported by two trials) included one participant receiving the MI-E protocol experiencing haemodynamic compromise. Nine (22.5%) of the control group compared to two (6%) MI-E participants experienced secretion encumbrance with severe hypoxaemia requiring reintubation (RR 0.25, 95% CI 0.06 to 1.10). In the lung volume recruitment trial, one participant experienced an elevated blood pressure for more than 30 minutes. No participant experienced new-onset arrhythmias, heart rate increased by more than 25%, or a pneumothorax.For outcomes assessed using GRADE, we based our downgrading decisions on unclear risk of bias, inability to assess consistency or publication bias, and uncertainty about the estimate of effect due to the limited number of studies contributing outcome data.

AUTHORS' CONCLUSIONS

The overall quality of evidence on the efficacy of cough augmentation techniques for critically-ill people is very low. Cough augmentation techniques when used in mechanically-ventilated critically-ill people appear to result in few adverse events.

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.

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.

Continuous Positive Airway Pressure (CPAP) for prevention of recurrent pneumonia in the Neuromyelitis Optica patient

Introduction

Traumatic spinal cord injury patients with quadriplegia associated respiratory compromise are at an immediately increased risk of developing pneumonia, but the onset of pneumonia risk and use of prevention strategies in the patient with quadriplegia due to Neuromyelitis Optica has not been described.

Case report

This is a case of a Neuromyelitis Optica patient with quadriplegia, dysphagia and tracheostomy that suffered recurrent fevers due to respiratory infections. The non-specific presentation and test results led to extensive testing, while the frequent recurrence resulted in the patient residing in the acute care hospital 201 days and outside of this hospital only 118 days during the period of August 2011 to June 2012. The initiation of CPAP 10 cm while sleeping overnight for 8–10 h eliminated the recurrence of respiratory infections and thereby reduced both the frequency and duration of the patient's hospital stays.

Conclusions

Patients with Neuromyelitis Optica differ from those with traumatic spinal cord injury as they have a chronic progressive systemic illness that causes continued deterioration of their nervous system resulting in the need for routine monitoring that ensures the timely addition of CPAP for the prevention of pneumonia and its associated medical expenses.

Acute and chronic respiratory failure

Respiratory failure (RF) can be attributed to a plethora of neuromuscular diseases (NMDs) and manifests clinically in a multitude of overt or more subtle ways. The basic principles of pathophysiology, diagnosis and treatment of neurologic diseases and of RF apply concomitantly to this subset of patients. Various entities should be approached according to the latest evidence-based recommendations. Treatment follows the natural disease progression, from minimal respiratory assistance to mechanical ventilation (MV). A comprehensive treatment plan has to be formulated that takes into consideration the patient's wishes.

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.

Respiration following spinal cord injury: evidence for human neuroplasticity

Respiratory dysfunction is one of the most devastating consequences of cervical spinal cord injury (SCI) with impaired breathing being a leading cause of morbidity and mortality in this population. However, there is mounting experimental and clinical evidence for moderate spontaneous respiratory recovery, or "plasticity", after some spinal cord injuries. Pre-clinical models of respiratory dysfunction following SCI have demonstrated plasticity at neural and behavioral levels that result in progressive recovery of function. Temporal changes in respiration after human SCI have revealed some functional improvements suggesting plasticity paralleling that seen in experimental models-a concept that has been previously under-appreciated. While the extent of spontaneous recovery remains limited, it is possible that enhancing or facilitating neuroplastic mechanisms may have significant therapeutic potential. The next generation of treatment strategies for SCI and related respiratory dysfunction should aim to optimize these recovery processes of the injured spinal cord for lasting functional restoration.

Noninvasive respiratory management and diaphragm and electrophrenic pacing in neuromuscular disease and spinal cord injury

The purpose of this monograph is to describe noninvasive management of respiratory muscle weakness/paralysis for patients with neuromuscular disease (NMD) and spinal cord injury (SCI). Noninvasive ventilation (NIV) assists and supports inspiratory muscles, whereas mechanically assisted coughing (MAC) simulates an effective cough. Long-term outcomes will be reviewed as well as the use of NIV, MAC, and electrophrenic pacing (EPP) and diaphragm pacing (DP) to facilitate extubation and decannulation. Although EPP and DP can facilitate decannulation and maintain alveolar ventilation for high-level SCI patients when they cannot use NIV because of lack of access to oral interfaces, there is no evidence that they have any place in the management of NMD.

Physical exercise reduces cardiac defects in type 2 spinal muscular atrophy-like mice

Spinal muscular atrophy (SMA), the leading genetic cause of death in infants worldwide, is due to the misexpression of the survival of motor neuron protein, causing death of motor neurons. Several clinical symptoms suggested that, in addition to motor neurons, the autonomic nervous systems could be implicated in the cardiac function alterations observed in patienst with SMA. These alterations were also found in a severe SMA mouse model, including bradycardia and a reduction of sympathetic innervation, both associated with autonomic imbalance. In the present study, we investigate the extent of autonomic dysfunction and the effects of a running-based exercise on the altered cardiorespiratory function in type 2 SMA-like mice. We observed that the SMA induced: (1) a dramatic alteration of intrinsic cardiac conduction associated with bradycardia; (2) a severe cardiomyopathy associated with extensive ventricular fibrosis; and (3) a delay in cardiac muscle maturation associated with contractile protein expression defects. Furthermore, our data indicate that the sympathetic system is not only functioning, but also likely contributes to alleviate the bradycardia and the arrhythmia in SMA-like mice. Moreover, physical exercise provides many benefits, including the reduction of cardiac protein expression defect, the reduction of fibrosis, the increase in cardiac electrical conduction velocity, and the drastic reduction in bradycardia and arrhythmias resulting in the partial restoration of the cardiac function in these mice. Thus, modulating the cardiorespiratory function in SMA could represent a new target for improving supportive care and for developing new pharmacological and non-pharmacological interventions that would most certainly include physical exercise.