Pathophysiological and clinical aspects of breathing after stroke

Bedside Ultrasound to Identify and Predict Severity of Dysphagia Following Ischemic Stroke: Human Versus Artificial Intelligence

OBJECTIVE

Dysphagia is a significant ischemic stroke complication that can lead to aspiration. Identification of at-risk patients can be logistically difficult and costly. Researchers investigated whether quantitative ultrasound assessment of hyoid bone movement during induced swallowing would predict failure of videofluoroscopy (VFS) or fiberoptic endoscopic evaluation of swallowing (FEES), as determined by a penetration-aspiration scale (PAS) score. Additionally, ability of a machine learning (ML) algorithm to predict PAS success or failure from real-time ultrasound video recordings was assessed.

METHODS

A prospective, single-blinded, observational pilot study was conducted from June 2019 through March 2020 at a comprehensive stroke center on a convenience sample of patients admitted with diagnosis of acute ischemic stroke undergoing VFS or FEES as part of dysphagia assessment. Researchers performed a midsagittal airway ultrasound during swallowing in patients receiving an objective swallowing assessment by speech language pathologists who were blinded to ultrasound results. Sonologists measured hyoid bone movement, and researchers then constructed an ML algorithm designed for real-time video analysis using a long short-term memory network with an embedded VGG16 convolutional neural network.

RESULTS

Videos from 69 patients were obtained with their respective PAS results. In total, 90% of available videos were used for algorithm training. After training, the ML algorithm was challenged with the 10% previously unseen videos and then compared with PAS outcomes. Statistical analysis included logistic regression and correlation matrix testing on human ultrasound measurements. Cohen's κ was calculated to compare deep learning algorithm prediction with PAS results. Measurement of hyoid bone elevation, forward displacement, total displacement and mandible length was unable to predict PAS assessment outcome (p values = 0.36, 0.13, 0.11 and 0.32, respectively). The ML algorithm showed substantial agreement with PAS testing results for predicting test outcome (κ = 0.79; 95% confidence interval: 0.52-1.0) CONCLUSION: Manual ultrasound measurement of hyoid movement during swallowing in stroke patients failed to predict PAS swallowing results. However, an ML algorithm showed substantial agreement with PAS results despite a small data set, which could greatly improve access to dysphagia assessment in the future.

One-Year Survival of Ischemic Stroke Patients Requiring Mechanical Ventilation

BACKGROUND

The outcome of patients with acute ischemic stroke who require mechanical ventilation has been poor. Intubation due to a reversible condition could be associated with better 1-year survival.

METHODS

All adult patients treated in Helsinki University Hospital in 2016-2020 who were admitted because of an ischemic stroke (either stroke or thrombosis seen on imaging) and needed mechanical ventilation were included in this retrospective cohort study. Data on demographics, medical history, index stroke, and indication for intubation were collected. The primary outcome was 1-year mortality. Secondary outcomes were modified Rankin Scale (mRS) score at 3 months and living arrangements at 1 year.

RESULTS

The mean age of the cohort (N = 121) was 66 ± 11 (mean ± SD) years, and the mean admission National Institutes of Health Stroke Scale score was 17 ± 10. Forty-four (36%) patients were male. The most common indication for intubation was unconsciousness (51%), followed by respiratory failure or airway compromise (28%). One-year mortality was 55%. Three-month mRS scores were available for 114 (94%) patients, with the following distribution: 0-2, 18%; 3-5, 28%; and 6 (dead), 54%. Of the 1-year survivors, 72% were living at home. In the multivariate analysis, only age over 75 years and intubation due to unconsciousness, respiratory failure, or cardiac arrest remained significantly associated with mortality.

CONCLUSIONS

The indication for intubation seems to significantly affect outcome. Functional outcome at 3 months is often poor, but a great majority of 1-year survivors are able to live at home.

The relationship of respiratory functions and respiratory muscle strength with trunk control, functional capacity, and functional independence in post‐stroke hemiplegic patients

BACKGROUND

Cardiorespiratory system involvement and early fatigue observed in stroke patients complicate the rehabilitation process and affect their ability to perform daily activities and functional independence.

AIM

It was aimed to determine the relationship between respiratory functions and respiratory muscle strength with trunk control, functional capacity, and functional independence in hemiplegic patients after stroke.

MATERIALS AND METHODS

Twenty-five volunteers who were diagnosed with post-stroke hemiplegia were included in the study. Sociodemographic and physical characteristics were recorded. Pulmonary function test (PFT), respiratory muscle strength, Trunk Impairment Scale (TIS), Timed-Up and Go Test (TUG), and Barthel Index (BI) were applied.

RESULTS

There was a moderate negative correlation between TUG scores and PFT results (r = 0.413-0.502; p = 0.011-0.04), except for PEF (%) and FEV1/FVC. Also, there were statistically significant correlation between TIS scores and FEV1(%) (r = 0.505; p = 0.012), FVC(%) (r = 0.449; p = 0.024). On the other hand, there was no statistically significant relationship between BI results and any parameter of the PFT (p > 0.05). There was no statistically significant correlation between respiratory muscle strength and TUG, TIS, BI (p > 0.05).

CONCLUSION

It has been shown that respiratory functions are associated with functional capacity and trunk control. However, it was found that there was no relationship between respiratory muscle strength and functional capacity, trunk control, and functional independence. It is thought that considering these parameters in the assessment of patients will contribute to the creation of individual and effective rehabilitation programs. The respiratory system should be systematically assessed in stroke rehabilitation and considered as part of a holistic approach.

CLINICAL TRIAL REGISTRATION

NCT05290649 (retrospectively registered) (clinicaltrials.gov).

Feasibility of a standardized protocol for respiratory training with intermitted positive pressure breathing ventilator application in dysphonia and dysarthria

BACKGROUND

Brain damage can affect several functions related to speech production leading to dysphonia and dysarthria. Most rehabilitation treatments focus on articulation training rather than on pneumophonic coordination and respiratory muscle strength. Respiratory training using an intermitted positive pressure breathing (IPPB) ventilator can be used for this last purpose; no agreement on a standard protocol has been reached to date.

AIM

To evaluate the feasibility and the effectiveness of a standardized incremental protocol of respiratory training using IPPB to treat dysphonia and dysarthria.

DESIGN

Case series study.

SETTING

Neuropsychological Rehabilitation Unit in an Italian Neurorehabilitation Division.

POPULATION

Thirty-two subjects with dysphonia and dysarthria resulting from neurological lesion.

METHODS

Participants were assessed using clinical evaluation scales (GIRBAS scale of dysphonia, Robertson dysarthria profile), respiratory function test, and arterial blood gas analysis in air. The evaluations were performed at baseline and after 20 sessions of respiratory training with IPPB. The protocol provided a default increment of ventilator parameters. All subjects also underwent a standard speech and language therapy treatment. A satisfaction survey to assess acceptability and the Goal Attainment Scale were applied.

RESULTS

All participants fulfilled the protocol. No complications or discomfort were reported. Subjects' satisfaction at survey was 97.7%. After respiratory training, all respiratory function parameters increased, but only maximal voluntary ventilation (MVV), maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP) were statistically significant (P<0.05). Clinical evaluation scales significantly improved (P<0.05). Correlation between respiratory function parameters and clinical evaluation scales showed a moderate correlation between MVV, MEP, MIP, and Robertson dysarthria profile (P<0.01). A weak correlation was found between MIP, MVV, and GIRBAS scale (P<0.05).

CONCLUSIONS

Our protocol showed to be practical and well-tolerated. After respiratory training, MVV, MIP and MEP improved in significantly. Clinical scale scores improved in all participants.

CLINICAL REHABILITATION IMPACT

Respiratory training using IPPB ventilator can be useful in implementing speech and language treatments in subjects with dysphonia and dysarthria linked to brain injury.

Stroke and breathing

Stroke remains a leading cause of neurologic disability with wide ranging effects, including a variety of respiratory abnormalities. Stroke may influence the central control of the respiratory drive and breathing pattern, airway protection and maintenance, and the respiratory mechanics of inspiration and expiration. In the acute phase of stroke, the central control of breathing is affected by changes in consciousness, cerebral edema, and direct damage to brainstem respiratory centers, resulting in abnormalities in respiratory pattern and loss of airway protection. Common acute complications related to respiratory dysfunction include dysphagia, aspiration, and pneumonia. Respiratory control centers are located in the brainstem, and brainstem stroke causes specific patterns of respiratory dysfunction. Depending on the exact location and extent of stroke, respiratory failure may occur. While major respiratory abnormalities often improve over time, sleep-disordered breathing remains common in the subacute and chronic phases and worsens outcomes. Respiratory mechanics are impaired in hemiplegic or hemiparetic stroke, contributing to worse cardiopulmonary health in stroke survivors. Interventions to address the respiratory complications are under researched, and further investigation in this area is critical to improving outcomes among stroke survivors.

Efficacy of chest expansion resistance exercise on respiratory function, trunk control and dynamic balance in patients with chronic stroke: A Comparative study

Background

Motor impairments caused by stroke result in impaired diaphragmatic and respiratory muscle function, changes in thoracic biomechanics on the hemiparetic side ultimately resulting in decreased efficiency of lung ventilation. This study aimed to examine the efficacy of chest expansion resistance exercise (CERE) on respiratory function, trunk control ability, and balance in patients with chronic stoke. Following a purposive sampling, thirty-five patients with chronic stroke were randomly allocated into two groups, i.e., the experimental group receiving CERE with conventional therapy and the control group receiving conventional therapy alone. Both the groups received therapy four times per week for a period of four weeks (total 16 sessions). Following assessments were done before and after treatment in both the groups: chest expansion ( axillary, nipple, xiphisternal levels) using measure tape, respiratory muscle strength using micro-respiratory pressure meter, trunk control using the Trunk Impairment Scale, and balance using mini-Balance Evaluation Systems Test.

Results

Both groups had 17 participants each (n = 34, drop-outs = 1) consisting of 12 males and 5 females having a mean age of 56.5 ± 12.98 years and 59.7 ± 10.2 years, respectively. Intra-group analysis showed a statistically significant increase in mean values of chest expansion, respiratory muscle strength, trunk control ability, and balance in the experimental group whereas the control group showed improvement only in trunk control ability and balance. Inter-group comparison revealed a better improvement in all the outcome variables in experimental group compared to the control group.

Conclusions

Based on these results, this study proved that CERE was more effective in improving respiratory function, trunk control, and balance in patients with chronic stroke.

Comparison of training effects between underwater treadmill gait training and overground gait training on the walking ability and respiratory function in patients with chronic severe hemiplegic stroke: A randomized, controlled, preliminary trial

Background: The need to develop a more effective intervention to obtain a functional recovery of stroke patients who are unable to perform land-based treadmill gait training has been widely reported. Thus, this pilot study aimed to identify a gait training type that could lead to improved gait and respiratory functioning in adult patients with chronic severe hemiplegic stroke.Objectives: To examine whether underwater treadmill or/and overground gait training could be more effective in stroke patients.Methods: In this single-blinded, randomized, controlled, comparative study, 22 patients with severe hemiplegic stroke in a rehabilitation hospital were randomly assigned to the experimental (underwater treadmill gait training) or control group (overground gait training). All participants performed a 60-min neurodevelopmental treatment (five times/week for 12 weeks). Each group performed 30-min underwater or overground gait training (two times/week for 12 weeks). Gait and respiratory function were measured before and after the 12-week training.Results: For the walking variables, step-time difference changes post-training showed significant differences between the groups (-.06 vs. +.04 s, p < .05). Both groups showed significant increases in the maximal voluntary volume (MVV) at post compared to pre training (p < .05). The post-training MVV values were significantly different between the two groups (+23.35 vs. +4.76 L, p < .05).Conclusions: In severe stroke patients, underwater treadmill gait training can be more effective in improving gait and respiratory function than overground gait training and could be an effective clinical intervention tool for the training of such patients.

Locked-In Syndrome: Practical Rehabilitation Management

Locked-in syndrome is a rare and devastating condition that results in tetraplegia, lower cranial nerve paralysis, and anarthria with preserved cognition, vertical gaze, and upper eyelid movements. Although acute management is much like that of any severe stroke, rehabilitation and recovery of these patients have not been previously described. Challenges relevant to this population include blood pressure management and orthostasis, timing and appropriateness of reinstating oral feeding, ventilatory support, decannulation after tracheostomy, bowel and bladder management, vestibular dysfunction, and eye care. Targeted rehabilitation of head, neck, and trunk stability to improve function, and proper fit in an appropriate wheelchair are essential to assist with mobility. Rehabilitation interventions should include a focus on distal motor control and upright tolerance training followed by balance and mobility exercises. In addition, special considerations must be given to developing early methods of communication through use of augmentative systems to call for help and express needs. These systems along with additional technology provide the basis to promote connectivity to family and friends through the use of social media and the internet. Establishment of communication, mobility, and connectivity is essential in promoting independence, autonomy, and improving quality of life. Overall, with specialized rehabilitative care and access to the proper equipment, long-term outcomes and quality of life in these patients can be favorable.

Obstructive sleep apnea syndrome and neuropsychological function in pediatric stroke

OBJECTIVES

To assess the prevalence of obstructive sleep apnea syndrome (OSAS) in children with arterial ischemic stroke (AIS) and to evaluate its association with neuropsychological outcomes.

METHODS

We conducted a cross-sectional study of sleep health and neuropsychological outcome in children with AIS. A consecutive cohort of children attending a stroke clinic were assessed using a standardized pediatric sleep questionnaire (PSQ) and standardized measures of pediatric stroke outcome and intellectual, executive and adaptive function. High risk for OSAS was defined as PSQ score ≥0.33.

RESULTS

Overall, 102 children were included (55% males, median age: 9 years [interquartile-range [IQR]: 6-14]). The prevalence of OSAS in children with AIS was significantly higher compared to published normative prevalence rate (25.5% vs 5%, p < 0.001). Children with OSAS were more likely to have infarcts affecting both the anterior and posterior circulation (37.5% vs 9.5%, p = 0.021). In addition, children with OSAS had significantly higher median Pediatric Stroke Outcome Measure (PSOM) scores (2 [IQR: 0-2] vs 1 [IQR: 1-3.5], p = 0.01) and were more likely to be prescribed concomitant medications affecting sleep architecture (50% vs 22.4%, p = 0.007). OSAS was associated with significantly lower scores on intellectual, memory, cognitive, behavioral, attention, executive and adaptive function scales. The association between PSQ and intellectual ability and working memory remained statistically significant upon controlling for potential confounding factors including stroke related characteristics (neurologic impairment and arterial territory).

CONCLUSIONS

The prevalence of OSAS in children with AIS compared to healthy controls is significantly elevated and is associated with poor neuropsychological outcomes. We highlight the importance of regular screening for OSAS - a modifiable risk factor - in children with AIS. The specific risk factors for OSAS and the potential benefits of therapeutic interventions in this patient population warrant further investigation.

Respiratory repercussions of neurological diseases and how best to manage them

Introduction: The high incidence of respiratory impairments in patients with neurological diseases is recognized, but the design, dosage, and effectiveness of interventions to manage them are seen as an ongoing challenge.Areas covered: This article summarizes the evidence regarding the respiratory impairments in major neurological diseases, and how to best manage them.Expert opinion: On the balance of available evidence, respiratory impairments are part of the clinical profile of neurological diseases including Multiple Sclerosis, Stroke, and Parkinson's Disease, acquiring more importance as the pathologies progress. It is recognized that knowledge gaps remain in some areas of relevance related to respiratory function and further research is required. When considering the therapeutic options, the respiratory training emerges as the approach with most evidence. However, important questions remain unsolved: what kind, how much, and how to best include respiratory interventions is uncertain. At present, respiratory programs also fail to include clinically relevant factors such as ambulation and trunk stability.

Relationship between pulmonary function, functional independence, and trunk control in patients with stroke

OBJECTIVE

Stroke often leads to abnormalities in muscle tone, posture, and motor control that may compromise voluntary motor function, thus affecting the motor control required for maintaining the synergy of both peripheral and respiratory muscles. To evaluate respiratory muscle strength, pulmonary function, trunk control, and functional independence in patients with stroke and to correlate trunk control with the other variables.

METHODS

This was a cross-sectional study of patients diagnosed with stroke. We assessed respiratory muscle strength, trunk control as assessed by the Trunk Impairment Scale, spirometric variables, and the Functional Independence Measure.

RESULTS

Forty-four patients were included. Pulmonary function and respiratory muscle strength were significantly lower than predicted for the study population, and the mean Trunk Impairment Scale score was 14.3 points. The following significant correlations were found between the variables: trunk control vs. maximal inspiratory pressure (r = 0.26, p < 0.05); trunk control vs. forced vital capacity (r = 0.28, p < 0.05); trunk control vs. forced expiratory volume in one second (r = 0.29, p < 0.05), and trunk control vs. the Functional Independence Measure (r = 0.77, p < 0.05).

CONCLUSION

The present study showed that respiratory muscle strength, pulmonary function, functional independence, and trunk control are reduced in patients diagnosed with stroke.

Chest wall volume and asynchrony in stroke and Parkinson's disease subjects: A case-control study

Background

The expansion of the rib cage and abdomen occurs in a synchronic way during a coordinated contraction of the diaphragm and the abdominal and intercostal muscles under normal conditions and healthy. The presence of restrictive respiratory disease may lead to uncoordinated action of the respiratory muscles which affects breathing pattern and chest wall volumes. The aim of this study was to evaluate chest wall volumes, chest wall asynchrony and inspiratory paradoxical movement of breathing, as well as the influence of the time of disease diagnosis in subjects with Parkinson’s disease and post-Stroke in comparison to healthy individuals.

Methods

Total and compartmental chest wall volumes, chest wall asynchrony and paradoxical movement were measured at rest in a seated position by Optoelectronic Plethysmography in 76 individuals (29 healthy individuals, 20 post-Stroke and 27 Parkinson’s disease subjects). Post-stroke and Parkinson’s disease subjects were also grouped according to the length of diagnosis.

Results

In both groups with restrictive respiratory disease we observed that pulmonary rib cage compartment (V_RCp) volume is reduced when compared to healthy subjects (p <0.05). This same pattern was observed when analyzing post-stroke subjects with more than three years of diagnosis and Parkinson’s subjects with less than three years of diagnosis (p<0.05). Furthermore, post-stroke subjects with inspiratory paradoxical movement showed decreased total and compartmental chest wall volumes (p<0.05), while individuals with Parkinson’s disease with inspiratory paradoxical movement only presented a decrease in pulmonary rib cage compartment volume (p<0.05).

Conclusion

Our study presents new findings for better understanding of chest wall volumes and chest wall asynchrony in post-stroke and Parkinson’s disease individuals. Half of the subjects with post-Stroke and Parkinson’s disease presented inspiratory paradox movement, but changes in breathing pattern was especially observed in post-stroke subjects with more than three years of diagnosis.

Effectiveness of mid-thoracic spine mobilization versus therapeutic exercise in patients with subacute stroke: A randomized clinical trial

BACKGROUND

Although commonly used in clinical settings, evidence regarding the beneficial effectiveness of joint mobilization and therapeutic exercise in patients with stroke is still lacking.

OBJECTIVE

This study aimed to investigate the effects of mid-thoracic spine mobilization and therapeutic exercise on dynamic balance and inspiratory function in patients with subacute stroke.

METHODS

The participants included 33 patients with subacute stroke. Participants were randomly allocated to 1 of 2 groups: (1) a group that received segmental mobilization (T4-8), and (2) a group that received foam roller exercises (T4-8). Outcome measure included the limits of stability (LOS), inspiratory function, and global rating of change (GRC).

RESULTS

The improvement in inspiratory function was statistically significant at 4 and 6 weeks after the initiation of the intervention and changes in the LOS were statistically significant at 6 weeks in the mobilization group (p< 0.05). In addition, 15 of 17 (88.2%) participants in the mobilization group, compared to 9 of 16 participants (56.2%) in the exercise group, indicated a GRC score of +4 or higher at the 4-week follow-up.

CONCLUSIONS

This study demonstrates that patients with subacute stroke who receive mid-thoracic spine mobilization demonstrate effective short-term improvements in LOS and GRC.

Proprioceptive Neuromuscular Facilitation for Accessory Respiratory Muscles Training in Patients After Ischemic Stroke

This study focused on how pulmonary function is affected by proprioceptive neuromuscular facilitation (PNF) of accessory respiratory muscles in the chronic post-stroke phase. The study involved patients who had had ischemic stroke 6 months or more before the PNF treatment investigated. The objective was to define the effect of PNF on bioelectrical resting and maximum activity of the accessory muscles. Patients were randomly assigned to PNF treatment and just positioning treatment as a reference for comparison; 30 patients each. Electromyography of accessory muscles was investigated before and after physiotherapeutic treatments. We found that there was a greater reduction in EMG activity in all muscles investigated after PNF compared to positioning treatment alone. A reduction of muscle activity due to PNF concerned both affected and unaffected body side, but it was greater on the affected side. We conclude that a reduction of the accessory respiratory muscle activity due to PNF treatment could be of benefit in chronic stoke patients in that it would help normalize breathing pattern and thereby prevent the development of hypoxia.

Immediate Effects of Thoracic Spinal Manipulation on Pulmonary Function in Stroke Patients: A Preliminary Study

OBJECTIVES

The purpose of this study was to investigate the immediate effects of thoracic spinal manipulation (TSM) on pulmonary function in stroke patients.

METHODS

Thirty-six volunteers with stroke (20 men, 16 women) were recruited and randomized to a TSM group (n = 18) and a sham group (n = 18). All participants underwent initial pulmonary function test and then rested supine for 10 minutes before the intervention. Pulmonary function test was repeated immediately after the intervention. Forced vital capacity, forced expiratory volume at 1 second, maximum voluntary ventilation, and residual volume were measured by a spirometer in preintervention and post-intervention.

RESULTS

Significant between-group differences were observed in forced vital capacity and forced expiratory volume at 1 second in the TSM group (P < .05). No significant changes in dependent variables were seen in the sham group.

CONCLUSION

The pulmonary function values for patients in the TSM group were significantly enhanced with no significant improvement in maximum voluntary ventilation and residual volume. Mechanical factors may be responsible for the improved pulmonary function in the TSM group.

Anterior and posterior diaphragm kinesio taping for intractable hiccups after ischemic stroke: A case report

RATIONALE

Pathophysiologic mechanisms of the central nervous system, such as stroke, can be associated with intractable hiccups. Intractable hiccups can be associated with potentially fatal consequences, thus requiring safe management in an inpatient rehabilitation facility (IRF) setting with a multidisciplinary team approach to optimize mobility and feeding.

PATIENT CONCERNS

A 49-year-old male presented to the emergency department with complaints of vomiting and dizziness.

DIAGNOSES

Head computed tomography revealed moderate acute inferior cerebellar infarct in the territory of the posterior inferior cerebellar artery. He required a percutaneous endoscopic gastrostomy tube for feeding and developed severe intractable hiccups which he rated 7/10 on the hiccup assessment instrument (HAI) on IRF admission. Functional independence measure (FIM) score for transfers was 2 (maximum assist), walking was 1 (total assist), stairs were not attempted on IRF admit due to safety concerns, and feeding (eating) was 1 (total assist).

INTERVENTIONS

Anterior and posterior diaphragm kinesio taping was applied on day 6 of IRF physical therapy in an attempt to inhibit diaphragm spasm and intractable hiccups given that pharmacologic interventions had not been effective up to that point (Table 3).

OUTCOMES

The HAI decreased from 7/10 on day 6 of IRF physical therapy to 0/10 on day 8. The taping was reapplied every 3 to 5 days. On IRF day 9, his diet was advanced to a regular consistency with extra moisture and thin liquids. On day 21, hiccup severity remained 0/10 on the HAI, while FIM score for transfers was 4 (minimal assist), walking was 4 (minimal assist), stairs was 4 (minimal assist), and feeding (eating) was 7 (independent).

LESSONS

Diaphragm kinesio taping is a very effective treatment at reducing hiccup severity in a patient after ischemic stroke, while at the same time reducing burden of care for caregivers per FIM score improvement and improving diet to that of regular consistency with extra moisture and thin liquids.

Liuzijue Qigong vs traditional breathing training for patients with post-stroke dysarthria complicated with abnormal respiratory control: study protocol of a single center randomized controlled trial

BACKGROUND

Stroke-induced dysarthria is caused by muscle weakness, sacral or muscular dystonia, and incoordination of the articulatory organ formed by organic lesions caused by cerebral vascular obstruction or sudden bursting of blood vessels in the brain, which may cause abnormal breathing patterns, pronunciation, resonance, rhythm, and unclear articulation. The Six Character Formula, or Liuzijue qigong (LQG), is an essential part of Chinese traditional exercises and focuses on breathing-speech synchronization. The purpose of the present study was to compare the effects of LQG with traditional breathing training (combined with basic articulation training in both groups) in patients with post-stroke dysarthria.

METHODS/DESIGN

The proposed study will be a single-center randomized controlled trial. A total of 100 patients, with a modified Frenchay Dysarthria Assessment (FDA) dysarthria assessment score < 27 and with a FDA speech breathing level ≥ b will be randomly divided into study (LQG, n = 50) and control (conventional breathing training, n = 50) groups. Basic articulation training will be conducted once a day, five times a week for 3 weeks. Data collection will be conducted at baseline, 1 week, and 2 weeks post-treatment initiation and after completion of the treatment (3 weeks). Comprehensive analyses will be conducted to measure and compare any differences in speech breathing dysfunction levels, comprehensive evaluation of dysarthria, maximum phonation time (MPT), maximal counting ability, signal-noise (S/Z) ratio, and loudness scales between the study and control groups.

DISCUSSION

This trial will provide evidence about the effectiveness of LQG for improvement of speech breathing function and speech ability in patients with post-stroke dysarthria complicated with abnormal breathing.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-INR-16010215. Registered 21 December 2016.

Outcomes in Patients With Acute Stroke Requiring Mechanical Ventilation: Predictors of Mortality and Successful Extubation

BACKGROUND

The majority of patients with acute stroke requiring mechanical ventilation have a poor prognosis and often present difficult decisions regarding extubation. The best criteria for planned extubation in these patients are uncertain.

METHODS

We reviewed the electronic medical records of patients hospitalized between 1/1/2010 and 12/15/2015 with acute stroke requiring mechanical ventilation to determine the mortality rate, the respiratory parameters recorded before planned extubation, and the reintubation rate.

RESULTS

This study included 226 patients. The mean age was 60.3 ± 14.3 years. The mean duration of mechanical ventilation was 6.5 ± 5.9 days. The overall in-hospital mortality rate was 56.6%. The best predictors of mortality were age and stroke volume calculated from radiographic images. One hundred and one patients had planned extubations; 9 patients (8.9%) required reintubation. There was no difference in respiratory parameters or Glasgow coma scale scores between those patients with successful extubation and those patients with failed extubation.

CONCLUSIONS

The in-hospital mortality rate of patients with acute stroke who require mechanical ventilation is quite high. The success rate with planned extubation is relatively good and comparable to rates in previous studies which largely involved patients with respiratory failure. There is no single weaning parameter or Glasgow coma scale score which identifies patients with high success rates.

Neuroprosthetics for Auricular Muscles: Neural Networks and Clinical Aspects

The mammalian external ear houses extrinsic and intrinsic auricular muscles. There are three extrinsic auricular muscles-the posterior, superior, and anterior auricular muscles-and six intrinsic muscles-the helicis major and minor, tragicus, anti-tragicus, transverse and oblique muscles. These muscles have been considered vestigial in humans. However, numerous therapeutic and diagnostic wearable devices are designed to monitor and alleviate the symptoms of neurological disorders, brainstem injuries, emotional states, and auditory functions, by making use of the neural networks of the auricular muscles and their locations, which are easily accessible for ergonomic wearable biomedical devices. They can also serve as a bio-controller of human neuroprosthetics. The functionality of these auricular muscles remains elusive and requires further experimentation for a more in-depth understanding of their anatomy. The aims of this review are (1) to provide a detailed account of the neural networks of the extrinsic and intrinsic auricular muscles, (2) to describe diagnostic and therapeutic functions of these muscles as demonstrated in the current literature, and (3) to outline existing and potential neuroprosthetic applications making use of the auricular muscles and their neural networks.

The correlation between diaphragm thickness, diaphragmatic excursion, and pulmonary function in patients with chronic stroke

[Purpose] This study aimed to investigate the correlation between the diaphragm thickness and diaphragm excursion, and pulmonary function in individuals with stroke. [Subjects and Methods] One hundred fourteen patients who were clinically diagnosed with ischemic or hemorrhagic stroke were included. The diaphragm thickness and excursion were assessed using ultrasonography, and the diaphragm thickening ratio was standardized using a formula. To analyze pulmonary function, we measured the forced vital capacity, forced expiratory volume in one second, and peak expiratory flow. [Results] A statistically significant correlation was found between the diaphragm thickness, thickness ratio, and diaphragm excursion; and the forced vital capacity, forced expiratory volume in one second, and peak expiratory flow. [Conclusion] This study demonstrated that there is a relationship between respiratory function and diaphragm thickness and diaphragm excursion, especially in the paretic side of the diaphragm. Therefore, the role of the respiratory muscles of the paretic side is important in rehabilitation programs to improve the respiratory function of stroke patients.

Upper thoracic spine mobilization and mobility exercise versus upper cervical spine mobilization and stabilization exercise in individuals with forward head posture: a randomized clinical trial

Background

Although upper cervical and upper thoracic spine mobilization plus therapeutic exercises are common interventions for the management of forward head posture (FHP), no study has directly compared the effectiveness of cervical spine mobilization and stabilization exercise with that of thoracic spine mobilization and mobility exercise in individuals with FHP.

Methods

Thirty-two participants with FHP were randomized into the cervical group or the thoracic group. The treatment period was 4 weeks, with follow-up assessment at 4 and 6 weeks after the initial examination. Outcome measures including the craniovertebral angle (CVA), cervical range of motion, numeric pain rating scale (NPRS), pressure pain threshold, neck disability index (NDI), and global rating of change (GRC) were collected. Data were examined with a two-way repeated-measures analysis of variance (group × time).

Results

Participants in the thoracic group demonstrated significant improvements (p < .05) in CVA, cervical extension, NPRS, and NDI at the 6-week follow-up compared with those in the cervical group. In addition, 11 of 15 (68.8%) participants in the thoracic group compared with 8 of 16 participants (50%) in the cervical group showed a GRC score of +4 or higher at the 4-week follow-up.

Conclusions

The combination of upper thoracic spine mobilization and mobility exercise demonstrated better overall short-term outcomes in CVA (standing position), cervical extension, NPRS, NDI, and GRC compared with upper cervical spine mobilization and stabilization exercise in individuals with FHP.

Trial registration

KCT0002307, April 11, 2017 (retrospectively registered).

Effects of positive expiratory pressure on chest wall volumes in subjects with stroke compared to healthy controls: a case-control study

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The PEP device at 10 cmH₂O may be a potential home treatment for stroke group.

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The intensities above 10 cmH₂O may lead to lung hyperinflation in stroke group.

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Stroke group reduced shortening velocity index for expiratory muscles during use PEP.

Background

Alterations in respiratory system kinematics in stroke lead to restrictive pattern associated with decreased lung volumes. Chest physical therapy, such as positive expiratory pressure, may be useful in the treatment of these patients;

however, the optimum intensity to promote volume and motion changes of the chest wall remains unclear.

Objective

To assess the effect of different intensities of positive expiratory pressure on chest wall kinematics in subjects with stroke compared to healthy controls.

Methods

16 subjects with chronic stroke and 16 healthy controls matched for age, gender, and body mass index were recruited. Chest wall volumes were assessed using optoelectronic plethysmography during quiet breathing, 5 minutes,

and recovery. Three different intensities of positive expiratory pressure (10, 15, and 20 cmH₂O) were administered in a random order with a 30 minutes rest interval between intensities.

Results

During positive expiratory pressure, tidal chest wall expansion increased in both groups compared to quiet breathing; however, this increase was not significant in the subjects with stroke (0.41 vs. 1.32 L, 0.56 vs. 1.54 L, 0.52 vs. 1.8 L, at 10, 15, 20 cmH₂O positive expiratory pressure, for stroke and control groups; p < 0.001). End-expiratory chest wall volume decreased in controls, mainly due to the abdomen, and increased in the stroke group, mainly due the pulmonary rib cage.

Conclusion

Positive expiratory pressure administration facilitates acute lung expansion of the chest wall and its compartments in restricted subjects with stroke. Positive expiratory pressure intensities above 10 cmH₂O should be used with caution as the increase in end-expiratory volume led to hyperinflation in subjects with stroke.

Metabolic Acidosis or Respiratory Alkalosis? Evaluation of a Low Plasma Bicarbonate Using the Urine Anion Gap

Hypobicarbonatemia, or a reduced bicarbonate concentration in plasma, is a finding seen in 3 acid-base disorders: metabolic acidosis, chronic respiratory alkalosis and mixed metabolic acidosis and chronic respiratory alkalosis. Hypobicarbonatemia due to chronic respiratory alkalosis is often misdiagnosed as a metabolic acidosis and mistreated with the administration of alkali therapy. Proper diagnosis of the cause of hypobicarbonatemia requires integration of the laboratory values, arterial blood gas, and clinical history. The information derived from the urinary response to the prevailing acid-base disorder is useful to arrive at the correct diagnosis. We discuss the use of urine anion gap, as a surrogate marker of urine ammonium excretion, in the evaluation of a patient with low plasma bicarbonate concentration to differentiate between metabolic acidosis and chronic respiratory alkalosis. The interpretation and limitations of urine acid-base indexes at bedside (urine pH, urine bicarbonate, and urine anion gap) to evaluate urine acidification are discussed.

Purinergic regulation of vascular tone in the retrotrapezoid nucleus is specialized to support the drive to breathe

Cerebral blood flow is highly sensitive to changes in CO₂/H⁺ where an increase in CO₂/H⁺ causes vasodilation and increased blood flow. Tissue CO₂/H⁺ also functions as the main stimulus for breathing by activating chemosensitive neurons that control respiratory output. Considering that CO₂/H⁺-induced vasodilation would accelerate removal of CO₂/H⁺ and potentially counteract the drive to breathe, we hypothesize that chemosensitive brain regions have adapted a means of preventing vascular CO₂/H⁺-reactivity. Here, we show in rat that purinergic signaling, possibly through P2Y_2/4 receptors, in the retrotrapezoid nucleus (RTN) maintains arteriole tone during high CO₂/H⁺ and disruption of this mechanism decreases the CO₂ventilatory response. Our discovery that CO₂/H⁺-dependent regulation of vascular tone in the RTN is the opposite to the rest of the cerebral vascular tree is novel and fundamentally important for understanding how regulation of vascular tone is tailored to support neural function and behavior, in this case the drive to breathe.

DOI:http://dx.doi.org/10.7554/eLife.25232.001

We breathe to help us take oxygen into the body and remove carbon dioxide. Our cells use the oxygen to break down food to release energy, and as they do so they produce carbon dioxide as a waste product. Cells release this carbon dioxide back into the bloodstream so that it can be transported to the lungs to be breathed out. Carbon dioxide also makes the blood more acidic; if the blood becomes too acidic, tissues and organs may not work properly.

The brain uses roughly 25% of the oxygen consumed by the body and is particularly sensitive to the levels of gases and acidity in the blood. It has been known for more than a century that increased carbon dioxide causes blood vessels in the brain to widen, allowing the excess carbon dioxide to be carried away quickly. More recent work has shown that increased carbon dioxide also activates neurons called respiratory chemoreceptors. These in turn activate the brain centers that drive breathing, causing us to breathe more rapidly to help us remove surplus carbon dioxide.

But this scenario contains a paradox. If high levels of carbon dioxide cause widening of the blood vessels in the brain regions that contain respiratory chemoreceptors, this should, in theory, wash out that important stimulus, reducing the drive to breathe. So how does the brain prevent this unhelpful response? By studying the brains of adult rats, Hawkins et al. show that different rules apply to the brain centers that control breathing compared to other areas of the brain. In one such region, if the blood becomes too acidic, support cells called astrocytes release chemical signals called purines. This counteracts the tendency of high carbon dioxide levels to widen blood vessels in this region, and instead causes these vessels to become narrower.

This mechanism ensures that local levels of carbon dioxide in respiratory brain centers remain in tune with the demands of local networks, thereby maintaining the drive to breathe. The next challenges are to identify the molecular mechanisms that control the diameter of blood vessels in brain regions containing respiratory chemoreceptors, and to find out whether drugs that modulate these mechanisms have the potential to treat some respiratory conditions.

DOI:http://dx.doi.org/10.7554/eLife.25232.002

Neuropulmonology

Neuropulmonology refers to the complex interconnection between the central nervous system and the respiratory system. Neurologic injury includes traumatic brain injury, hemorrhage, stroke, and seizures, and in each there are far-reaching effects that can result in pulmonary dysfunction. Systemic changes can induce impairment of pulmonary function due to changes in the core structure and function of the lung. The conditions and disorders that often occur in these patients include aspiration pneumonia, neurogenic pulmonary edema, and acute respiratory distress syndrome, but also several abnormal respiratory patterns and sleep-disordered breathing. Lung infections, pulmonary edema - neurogenic or cardiogenic - and pulmonary embolus all are a serious barrier to recovery and can have significant effects on outcomes such as hospital course, prognosis, and mortality. This review presents the spectrum of pulmonary abnormalities seen in neurocritical care.

Intrarater reliabilities of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer for geriatric and stroke patients

[Purpose] This study aimed to verify the appropriate number of measurements and the intrarater reliabilities of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer (HHD) for geriatric and stroke patients. [Subjects and Methods] The subjects were 40 inpatients, who were divided into two groups: 20 stroke patients in the stroke group (SG), and 20 geriatric patients in the no-stroke group (N-SG). Measurements were performed three times using an HHD with a belt. The reliability was verified using Bland-Altman analysis and the intraclass correlation coefficient (ICC). [Results] ICC (1, 1) was >0.9. A systematic bias was not observed between the first and second measurement values except for the right side in N-SG. A systematic bias between the maximum value obtained during the first and second measurements and third measurement value was observed on the left side in N-SG, and on the non-paralyzed side in SG: the third measurement values were small in both cases. [Conclusion] Intrarater reliabilities were high for shoulder horizontal adductor strength measurements using an HHD with a belt for geriatric and stroke patients. Taking the systematic bias into consideration, these findings suggest that the required number of measurements is two.

Dynamic changes in sleep-related breathing abnormalities in bilateral paramedian mesencephalon and thalamus stroke: a follow-up case study

BACKGROUND

Bilateral paramedian thalamic stroke is characterized by hypersomnia, vertical gaze palsy, amnestic alteration, and apathic state. Combined lesion of the paramedian thalamus and mesencephalon bilaterally is extremely rare. Little is known about the breathing disturbances of the particular region due to the lesion. The following describes the specific case of a woman, age 62, with bilateral paramedian thalamic and mesencephalic stroke. Initially, the patient's complaints exhibited altered vigilance and vertical gaze palsy. Notably, following the acute phase, fluctuating hypersomnia was detected. The MRI (brain) revealed an ischemic lesion in the medial part of the mesencephalon and paramedian thalamus, bilaterally.

AIMS

The aim of the present study is to elucidate the involvement and characteristics of sleep-related breathing abnormalities in the clinical manifestation of the combined paramedian thalamic and mesencephalic stroke.

METHODS

Polysomnographic recordings were accomplished seven times with 1-week interval between the consecutive recordings, toward investigating the early changes of sleep and sleep-related breathing abnormalities.

RESULTS

Sleep structure examination featured a decrease in N3 and REM ratio and an increase in N1 and N2 ratio with minimal improvement during the recovery period. In contrast, significant changes were found in the breathing pattern: the initial central apnea dominance was followed by obstructive apneas with a gradual decrease of the total pathological respiratory events.

CONCLUSION

In addition to the structural abnormality of the sleep regulating network, sleep-disordered breathing is another possible cause of hypersomnia in patients afflicted with the present localization of the lesion.

Feasibility of Early Physical Therapy Program In-Hospital Patients with Acute Ischemic Stroke

BACKGROUND AND PURPOSE: Clinical practice guidelines for patients with stroke recommend early stroke rehabilitation at acute stroke unit care. The purpose of the study is to determine the feasibility of the application of feedback breathing device for respiratory training during the acute period in patients with ischemic cerebral stroke and appropriate program of physical therapy.MATERIAL AND METHODS: Seven patients in acute period – not later than 48 hours after the accident with light to moderate stroke severity under the NIHSS scale. The applied study methods are the following: functional respiratory evaluation, inspiratory capacity with incentive spirometer device, assessing diaphragmatic movement by ultrasonography.RESULTS: Better results in Forced Vital Capacity, Peak Expiratory Flow, inspiratory capacity and ultrasonography have been observed.CONCLUSION: An early targeted impact on respiratory disorders in patients with ischemic cerebral stroke is applicable. To determine the clinical significance larger studies are needed.

Ultrasonographic diaphragmatic motion analysis and its correlation with pulmonary function in hemiplegic stroke patients

Objective

To evaluate diaphragmatic motion via M-mode ultrasonography and to correlate it with pulmonary function in stroke patients.

Methods

This was a preliminary study comprised of ten stroke patients and sixteen healthy volunteers. The M-mode ultrasonographic probe was positioned in the subcostal anterior region of the abdomen for transverse scanning of the diaphragm during quiet breathing, voluntary sniffing, and deep breathing. We analyzed diaphragmatic motion and the relationship between diaphragmatic motion and pulmonary function.

Results

All stroke patients had restrictive pulmonary dysfunction. Compared to that exhibited by control subjects, stroke patients exhibited a significant unilateral reduction in motion on the hemiplegic side, primarily during volitional breathing. Diaphragmatic excursion in right-hemiplegic patients was reduced on both sides compared to that in control subjects. However, diaphragmatic excursion was reduced only on the left side and increased on the right side in left-hemiplegic patients compared to that in control subjects. Left diaphragmatic motion during deep breathing correlated positively with forced vital capacity (rho=0.86, p=0.007) and forced expiratory volume in 1 second (rho=0.79, p=0.021).

Conclusion

Reductions in diaphragmatic motion and pulmonary function can occur in stroke patients. Thus, this should be assessed prior to the initiation of rehabilitation therapy, and M-mode ultrasonography can be used for this purpose. It is a non-invasive method providing quantitative information that is correlated with pulmonary function.

Inspiratory muscular training in chronic stroke survivors: a randomized controlled trial

OBJECTIVE

To assess the effectiveness of inspiratory muscular training (IMT) on measures of strength, resistance, functional performance, and quality of life (QOL) for chronic stroke survivors.

DESIGN

Double-blinded randomized controlled trial.

SETTING

Research laboratory.

PARTICIPANTS

Subjects (N=21) with stroke (11 men, 10 women; maximal inspiratory pressure [MIP] <90% of predicted values) were randomly assigned to the experimental (n=11) and control groups (n=10); 18 participants completed all testing and training.

INTERVENTIONS

Interventions were based on home-based training, with resistance adjusted biweekly to 30% of MIP for the experimental group. The control group underwent the same protocol without the threshold resistance valve. Both groups received home training 30 minutes a day 5 times a week for 8 weeks.

MAIN OUTCOME MEASURES

MIP, inspiratory muscular endurance (IME), functional performance, and QOL.

RESULTS

There were significant between-group differences for the MIP and IME measures. Significant changes were observed for only the experimental group for MIP (67.8±14.6 at baseline to 102.2±26.0cmH(2)O at posttraining) and IME (31.8±19.3 to 49.2±21.1cmH(2)O). No statistically significant differences were observed for measures of functional performance and QOL.

CONCLUSIONS

Significant short-term effects of the IMT program for inspiratory strength and endurance were observed in chronic stroke survivors. These findings gave some indications that IMT may benefit people with stroke, and it is feasible to be included in rehabilitation interventions with this population.

Neurological complications of acute ischaemic stroke

Complications after ischaemic stroke, including both neurological and medical complications, are a major cause of morbidity and mortality. Neurological complications, such as brain oedema or haemorrhagic transformation, occur earlier than do medical complications and can affect outcomes with potential serious short-term and long-term consequences. Some of these complications could be prevented or, when this is not possible, early detection and proper management could be effective in reducing the adverse effects. However, there is little evidence-based data to guide the management of these neurological complications. There is a clear need for improved surveillance and specific interventions for the prevention, early diagnosis, and proper management of neurological complications during the acute phase of stroke to reduce stroke morbidity and mortality.

Correlation between trunk control, respiratory muscle strength and spirometry in patients with stroke: an observational study

INTRODUCTION

 Stroke is the main cause of chronic disability in adults, and the effect of a stroke on the respiratory system depends on the structures affected by the lesion. 

OBJECTIVES

 To evaluate the correlation between trunk control, respiratory muscle strength and pulmonary function in individuals who suffered stroke. 

METHODS

 Observational, quantitative and descriptive study. Twenty-three patients who had a clinical diagnosis of ischaemic or haemorrhagic stroke. The trunk control was assessed through the Trunk Impairment Scale (TIS), and the respiratory muscle strength was assessed by manovacuometry by measuring the maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). For pulmonary function analysis, we measured forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), peak expiratory flow (PEF) and the Tiffeneau index (TIFF) through spirometry. 

RESULTS

 A consistent and statistically significant correlation was found between TIS and PEF (r = 0.489, p = 0.024) and between TIS and EPmax (r = 0.517, p = 0.016). No relation was found between the other variables of pulmonary function and TIS. 

CONCLUSION

 This study demonstrated that there is a relation between trunk control and respiratory muscular strength, especially concerning the expiratory muscles. However, there seems to be no relation between trunk control and pulmonary function in this series of individuals who suffered stroke.

Adaptive servoventilation (ASV) in patients with sleep disordered breathing associated with chronic opioid medications for non-malignant pain

BACKGROUND

Adaptive servoventilation (ASV) can be effective therapy for specific types of central apnea such as Cheyne-Stokes respiration (CSR). Patients treated chronically with opioids develop central apneas and ataxic breathing patterns (Biot's respiration), but therapy with CPAP is usually unsuccessful. There are no published studies of ASV in patients with sleep apnea complicated by chronic opioid therapy.

METHODS

Retrospective analysis of 22 consecutive patients referred for evaluation and treatment of sleep apnea who had been using opioid medications for at least 6 months, had an apnea-hypopnea index (AHI) > or = 20/h, and had been tested with ASV. Baseline polysomnography was compared with CPAP and ASV.

OUTCOME VARIABLES

AHI, central apnea index (CAI), obstructive apnea index (OAI), hypopnea index (HI), desaturation index, mean SpO2, lowest SpO2, time SpO2 < 90%, and degree of Biot's respiration.

RESULTS

Mean (SD) AHI measured 66.6/h (37.3) at baseline, 70.1/h (32.6) on CPAP, and 54.2/h (33.0) on ASV. With ASV, the mean OAI was significantly decreased to 2.4/h (p < 0.0001), and the mean HI increased significantly to 35.7/h (p < 0.0001). The decrease of CAI from 26.4/h to 15.6/h was not significant (p = 0.127). Biot's breathing persisted, and oxygenation parameters were unimproved with ASV.

CONCLUSIONS

Due to residual respiratory events and hypoxemia, ASV was considered insufficient therapy in these patients. Persistence of obstructive events could be due to suboptimal pressure settings (end expiratory and/or maximal inspiratory). Residual central events could be related to fundamental differences in the pathophysiology of CSR compared to opioid induced breathing disturbances.

Central periodic breathing observed on hospital admission is associated with an adverse prognosis in conscious acute stroke patients

BACKGROUND

Central periodic breathing (CPB) is common following acute stroke, but its prognostic significance is uncertain. We determined the frequency of CPB on admission with stroke and assessed whether it was related to outcome.

METHODS

We measured arterial oxygen saturation (SaO2), chest wall movements and nasal airflow continually with portable monitoring equipment in a large cohort of acute stroke patients, from arrival at hospital through acute assessment to reaching the ward. Baseline neurological examination and 3-month outcome (modified Rankin scale, MRS) were assessed blind to recordings. CPB was defined as cyclical rises and falls in ventilation, with intermittent reduced respiratory airflow or total apnoea.

RESULTS

CPB was common in acute stroke (33/138, 24%), but was poorly recognised by clinical staff. Patients with CPB were more likely to have a total anterior circulation syndrome and higher National Institutes of Health Stroke Scale scores than those without (both p<0.01). Patients with CPB had significantly higher median SaO2 than those without (p<0.01), unrelated to whether they received oxygen or not. At 3-month follow-up: 91% of patients with CPB were dead or dependent (MRS>or=3) compared with 53% of those without (OR 8.8; 95% CI 2.5-30.5); the association remained statistically significant after adjusting for covariates (OR 5.9; 95% CI 1.4-25.4).

CONCLUSION

CPB is independently associated with poor outcome after stroke, but is not by association with hypoxia. Further work is required to identify causes, effects and interventions that might improve effects of CPB.