Noninvasive Ventilatory Correction in Patients With Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Up-to-date advance in the relationship between OSA and stroke: a narrative review

PURPOSE

Obstructive sleep apnea (OSA) and stroke affect each other. In this review, we summarized the effect of OSA on the onset and recurrence of stroke, the prognosis, and the treatment of poststroke patients with OSA.

METHODS

Pubmed/MEDLINE were searched through May 2023 to explore the relationship between OSA and stroke. The relevant papers included OSA and stroke, OSA and recurrent stroke, and the prognosis and treatment of poststroke patients with OSA.

RESULTS

The results showed that OSA can promote the onset and recurrence of stroke and that OSA may adversely affect the prognosis of poststroke patients. The application of continuous positive airway pressure (CPAP) and other treatments may benefit poststroke patients with OSA, though the long term effects of treatment are not well documented.

CONCLUSION

Both the onset and recurrence of stroke closely correlated with OSA, but the specific mechanisms remain unclear. Further studies should be carried out to explore effective treatments in patients with stroke and OSA.

Effectiveness and feasibility of continuous positive airway pressure in patients with stroke and sleep apnea: a meta-analysis of randomized trials

STUDY OBJECTIVES

This meta-analysis aimed to investigate the feasibility and effectiveness of continuous positive airway pressure (CPAP) treatment in stroke patients with sleep apnea.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched from inception until July 28, 2022, for randomized controlled trials comparing the use of CPAP and usual treatment in patients with stroke or transient ischemic attack and sleep apnea. The primary outcome measures were the feasibility of CPAP therapy, neurological function, and functional status.

RESULTS

After screening 5,747 studies, 14 studies with 1,065 patients were included in this meta-analysis. Overall, 8 of the 14 studies recorded CPAP use, and the mean CPAP use was 4.47 hours per night (95% confidence interval [CI]: 3.85-5.09). The risk ratio of discontinuing CPAP was 1.50 (95% CI: 0.76-2.94; P = .24). Analysis of the neurofunctional scales showed that CPAP treatment improved neurological function (standardized mean difference: 0.28; 95% CI: 0.02-0.53), but there was substantial heterogeneity (I2 = 57%, P = .03) across the studies. CPAP treatment had no significant effect on functional status vs the control (standardized mean difference: 0.25; 95% CI: -0.01 to 0.51), but the studies also had substantial heterogeneity (I2 = 55%, P = .06).

CONCLUSIONS

CPAP treatment is feasible in patients with stroke and sleep apnea and may improve neurological outcomes in these patients. However, this finding should be interpreted with caution because of the substantial heterogeneity of current trials.

CITATION

Fu S, Peng X, Li Y, Yang L, Yu H. Effectiveness and feasibility of continuous positive airway pressure in patients with stroke and sleep apnea: a meta-analysis of randomized trials. J Clin Sleep Med. 2023;19(9):1685-1696.

Sleep-Disordered Breathing and Prognosis after Ischemic Stroke: It Is Not Apnea-Hypopnea Index That Matters

BACKGROUND

Sleep-disordered breathing (SDB) is highly prevalent after stroke and is considered to be a risk factor for poor post-stroke outcomes. The aim of this observational study was to evaluate the effect of nocturnal respiratory-related indices based on nocturnal respiratory polygraphy on clinical outcomes (including mortality and non-fatal events) in patients with ischemic stroke.

METHODS

A total of 328 consecutive patients (181 (55%) males, mean age 65.8 ± 11.2 years old) with confirmed ischemic stroke admitted to a stroke unit within 24 h after stroke onset were included in the analysis. All patients underwent standard diagnostic and treatment procedures, and sleep polygraphy was performed within the clinical routine in the first 72 h after admission. The long-term outcomes were assessed by cumulative endpoint (death of any cause, new non-fatal myocardial infarction, new non-fatal stroke/transient ischemic attack, emergency revascularization, emergency hospitalization due to the worsening of cardiovascular disease). A Cox-regression analysis was applied to evaluate the effects of nocturnal respiratory indices on survival.

RESULTS

The mean follow-up period comprised 12 months (maximal-48 months). Patients with unfavourable outcomes demonstrated a higher obstructive apnea-hypopnea index, a higher hypoxemia burden assessed as a percent of the time with SpO₂ < 90%, a higher average desaturation drop, and a higher respiratory rate at night. Survival time was significantly lower (30.6 (26.5; 34.7) versus 37.9 (34.2; 41.6) months (Log Rank 6.857, p = 0.009)) in patients with higher hypoxemia burden (SpO₂ < 90% during ≥2.1% versus <2.1% of total analyzed time). However, survival time did not differ depending on the SDB presence assessed by AHI thresholds (either ≥5 or ≥15/h). The multivariable Cox proportional hazards regression (backward stepwise analysis) model demonstrated that the parameters of hypoxemia burden were significantly associated with survival time, independent of age, stroke severity, stroke-related medical interventions, comorbidities, and laboratory tests.

CONCLUSION

Our study demonstrates that the indices of hypoxemia burden have additional independent predictive value for long-term outcomes (mortality and non-fatal cardiovascular events) after ischemic stroke.

Positive airway pressure therapy for post-stroke sleep disordered breathing: a systematic review, meta-analysis and meta-regression

BACKGROUND

Sleep disordered breathing (SDB) is an under-recognised independent risk factor and a potential consequence of stroke. We systematically reviewed and meta-analysed the effectiveness of positive airway pressure (PAP) therapy in improving post-stroke outcomes.

METHODS

We searched CENTRAL, Embase, PubMed, CINAHL, PsycINFO, Scopus, ProQuest, Web of Science and CNKI (China National Knowledge Infrastructure) for randomised controlled trials comparing PAP therapy against a control or placebo group. We evaluated the pooled effects of PAP therapy on recurrent vascular events, neurological deficit, cognition, functional independence, daytime sleepiness and depression using random effects meta-analyses.

RESULTS

We identified 24 studies. Our meta-analyses showed that PAP therapy reduced recurrent vascular events (risk ratio 0.47, 95% CI 0.28-0.78), and showed significant beneficial effects on neurological deficit (Hedges' g= -0.79, 95% CI -1.19- -0.39), cognition (g=0.85, 95% CI 0.04-1.65), functional independence (g=0.45, 95% CI 0.01-0.88) and daytime sleepiness (g= -0.96, 95% CI -1.56- -0.37). However, there was insignificant reduction in depression (g= -0.56, 95% CI -2.15-1.02). No publication bias was detected.

CONCLUSIONS

Post-stroke patients with SDB benefited from PAP therapy. Prospective trials are needed to determine the ideal initiation period and the minimum effective therapeutic dose.

Sleep-Disordered Breathing in Acute Stroke: A Single-Center, Prospective, Longitudinal Study

BACKGROUND

Sleep-disordered breathing (SDB) is common among acute stroke patients. We sought to investigate the prevalence, severity and type of SDB in consecutive acute stroke patients. Moreover, we aimed to identify independent predictors of SDB in the acute stroke setting and investigate potential associations between SDB and functional outcomes at three months.

METHODS

We prospectively studied consecutive acute stroke patients, who underwent overnight polysomnography within 72 h from symptom onset. Demographics, clinical and imaging characteristics were documented. Daytime sleepiness preceding the stroke, stroke severity on admission and functional outcome at three months were evaluated using the Epworth-Sleepiness Scale (ESS), National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS), respectively. SDB was documented using standard polysomnography criteria.

RESULTS

A total of 130 consecutive acute stroke patients were prospectively evaluated [110 with ischemic stroke and 20 with intracerebral hemorrhage, mean age 60.5 ± 10.9 years, 77% men, median NIHSS score on admission: 3 (IQR: 2-17)]. The rate of SDB detection on polysomnography recordings was 79% (95% CI: 71-86). Three variables were independently associated with the likelihood of SDB detection in multivariable analyses adjusting for potential confounders: age (OR per 10-year-increase: 2.318, 95% CI: 1.327-4.391, p = 0.005), male sex (OR: 7.901, 95% CI: 2.349-30.855, p = 0.001) and abnormal ESS-score (OR: 6.064, 95% CI: 1.560-32.283, p = 0.017). Among patients with SDB, congestive heart failure was independently associated with the likelihood of central apnea detection (OR: 18.295, 95% CI: 4.464-19.105, p < 0.001). Among all patients, increasing NIHSS score on admission (OR: 0.817, 95% CI: 0.737-0.891, p < 0.001) and Apnea-Hypopnea Index (OR: 0.979, 95% CI: 0.962-0.996, p = 0.020) emerged as independent predictors of excellent functional outcome at 3 months (mRS-scores 0-1).

CONCLUSION

The high prevalence and severity of SDB in acute stroke patients and its negative impact on functional outcome indicate the importance of polysomnography implementation in everyday clinical practice of acute stroke work-up and management.

Practice recommendations for the role of physiotherapy in the management of sleep disorders: the 2022 Brazilian Sleep Association Guidelines

This clinical guideline supported by the Brazilian Sleep Association comprises a brief history of the development of Brazilian sleep physiotherapy, outlines the role of the physiotherapist as part of a sleep health team, and describes the clinical guidelines in respect of the management of some sleep disorders by the physiotherapist (including sleep breathing disorders, i.e., obstructive sleep apnea, central sleep apnea, upper airway resistance syndrome, hypoventilation syndromes and overlap syndrome, and pediatric sleep breathing disorders; sleep bruxism; circadian rhythms disturbances; insomnia; and Willis-Ekbom disease/periodic limb movement disorder. This clinical practice guideline reflects the state of the art at the time of publication and will be reviewed and updated as new information becomes available.

The Role of Carbon Dioxide in the Rat Acute Stroke Penumbra

Purpose

The vasodilatory response to inhaled CO₂ occurs in the acute stroke ischemic penumbra and may be a potential therapeutic modality.

Methods

Twenty-two Sprague-Dawley rats were subjected to 90-min occlusion of the M2 segment of the middle cerebral artery (M2CAO) by endovascular technique. The animals were administered different C02 concentrations and scanned serially with 9.4 T MRI. Infarct tissue was determined by diffusion-weighted imaging (DWI) and hypoperfused tissue was determined by arterial spin labeling (PWI).

Results

4 animals were administered room air (RA)+ 6% CO₂ (group 1), 6 animals RA+12% CO₂ (Group 2) and 4 animals only RA (group 3). In the rats with CO₂ administered (groups 1 and 2), the DWI lesion to cerebral hypoperfusion volume ratio (SD) at pre-CO₂ administration, was 0.145(0.168), which increased to 0.708(0.731) during CO₂ administration and reduced to 0.533(0.527) post-CO₂ administration. In 9 of 10 rats the hypoperfused volume decreased when CO₂ was administered. When CO₂ was stopped the hypoperfused volume became larger again. Administration of RA+12% CO₂ (Group 2) decreased the volume of CBF hypoperfusion significantly compared to the control group (95%CI: 0.084 ± 0.0213, p = 0.004).

Conclusion

Inhaled CO₂ appears to reduce the size of the hypoperfused tissue volume during acute stroke and may be a potential modality for treatment of acute ischemic stroke. These findings will nonetheless need to be validated in a larger cohort in other centers.

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.

Sleep apnoea and ischaemic stroke: current knowledge and future directions

Sleep apnoea, one of the most common chronic diseases, is a risk factor for ischaemic stroke, stroke recurrence, and poor functional recovery after stroke. More than half of stroke survivors present with sleep apnoea during the acute phase after stroke, with obstructive sleep apnoea being the most common subtype. Following a stroke, sleep apnoea frequency and severity might decrease over time, but moderate to severe sleep apnoea is nevertheless present in up to a third of patients in the chronic phase after an ischaemic stroke. Over the past few decades evidence suggests that treatment for sleep apnoea is feasible during the acute phase of stroke and might favourably affect recovery and long-term outcomes. Nevertheless, sleep apnoea still remains underdiagnosed and untreated in many cases, due to challenges in the detection and prediction of post-stroke sleep apnoea, uncertainty as to the optimal timing for its diagnosis, and a scarcity of clear treatment guidelines (ie, uncertainty on when to treat and the optimal treatment strategy). Moreover, the pathophysiology of sleep apnoea associated with stroke, the proportion of stroke survivors with obstructive and central sleep apnoea, and the temporal evolution of sleep apnoea subtypes following stroke remain to be clarified. To address these shortcomings, the management of sleep apnoea associated with stroke should be integrated into a multidisciplinary diagnostic, treatment, and follow-up strategy.

Sleep disordered breathing as a cause and consequence of stroke: A review of pathophysiological and clinical relationships

Stroke is the leading cause of death and disability globally. Sleep disordered breathing (SDB), a potentially modifiable risk factor of stroke, is highly prevalent in stroke survivors. Evidence supports a causal, bidirectional relationship between SDB and stroke. SDB may increase the risk of stroke occurrence and recurrence, and worsen stroke outcome. While SDB is associated with an increased incidence of hypertension and cardiac arrhythmias, both of which are traditional stroke risk factors, SDB is also an independent risk factor for stroke. A number of characteristics of SDB may increase stroke risk, including intermittent hypoxemia, sympathetic activation, changes in cerebral autoregulation, oxidative stress, systemic inflammation, hypercoagulability, and endothelial dysfunction. On the other hand, stroke may also cause new SDB or aggravate preexisting SDB. Continuous positive airway pressure treatment of SDB may have a beneficial role in reducing stroke risk and improving neurological outcome after stroke. The treatment should be considered as early as possible, particularly when SDB is present post-stroke. The goal of this review is to highlight the strong link between SDB and stroke and to raise awareness for practitioners to consider the possibility of SDB being present in all stroke survivors.

Autotitrating Bilevel Positive Airway Pressure in Large Vessel Steno-Occlusive Stroke Patients With Suspected Sleep Apnea: A Multicenter Randomized Controlled Study

Background: We hypothesized that autotitrating bilevel positive airway pressure (auto-BPAP) favorably affects short-term clinical outcomes in hyperacute ischemic stroke.

Methods: In a multicenter, randomized, controlled trial patients with large vessel steno-occlusive stroke and clinically suspected sleep apnea were allocated to auto-BPAP or standard stroke care alone. Auto-BPAP was initiated within 24 h from stroke onset and performed over 48 h during diurnal and nocturnal sleep. Sleep apnea was assessed using cardiorespiratory polygraphy. Primary endpoint was early neurological improvement on National Institutes of Health Stroke Scale (NIHSS) score at 72 h. Safety and tolerability of BPAP, functional independence [modified Rankin Scale (mRS) 0–2], stroke recurrence, and mortality at 90 days were assessed.

Results: Due to low recruitment, the trial was prematurely stopped after 24 patients had been randomized (auto-BPAP, n = 14; control, n = 10): median baseline NIHSS 13 (5.5–18), 88% large vessel occlusion, and 12% large vessel stenosis. Polygraphy confirmed sleep apnea in 64% of auto-BPAP and 88% of control patients (p = 0.34). Adherence to auto-BPAP was achieved by 9 of the 14 (64%) patients. Between auto-BPAP and control patients, no differences were observed in early neurological improvement (median NIHSS change: −2.0, IQR = 7 points vs. −0.5, IQR = 3 points), 90 days functional independence (21 vs. 30%, p = 0.67), stroke recurrence (0 vs. 20%, p = 0.16), and death (14 vs. 20%, p = 1.0). No safety concerns were identified.

Conclusions: In this prematurely terminated trial, auto-BPAP was safe but did not show an effect on short-term clinical outcomes in selected ischemic stroke patients. Its tolerability, however, may be limited in hyperacute stroke care and needs to be improved before larger trials are conducted.

Clinical Trial Registration:ClinicalTrials.gov, identifier: NCT01812993.

EAN/ERS/ESO/ESRS statement on the impact of sleep disorders on risk and outcome of stroke

Sleep disorders are highly prevalent in the general population and may be linked in a bidirectional fashion to stroke, which is one of the leading causes of morbidity and mortality.Four major scientific societies established a task force of experts in neurology, stroke, respiratory medicine, sleep medicine and methodology, to critically evaluate the evidence regarding potential links and the impact of therapy. 13 research questions were evaluated in a systematic literature search using a stepwise hierarchical approach: first, systematic reviews and meta-analyses; second, primary studies post-dating the systematic reviews/meta-analyses. A total of 445 studies were evaluated and 88 included. Statements were generated regarding current evidence and clinical practice.Severe obstructive sleep apnoea (OSA) doubles the risk for incident stroke, especially in young to middle-aged patients. Continuous positive airway pressure (CPAP) may reduce stroke risk, especially in treatment-compliant patients. The prevalence of OSA is high in stroke patients and can be assessed by polygraphy. Severe OSA is a risk factor for recurrence of stroke and may be associated with stroke mortality, while CPAP may improve stroke outcome. It is not clear if insomnia increases stroke risk, while pharmacotherapy of insomnia may increase it. Periodic limb movements in sleep (PLMS), but not restless limb syndrome (RLS), may be associated with an increased risk of stroke. Preliminary data suggest a high frequency of post-stroke insomnia and RLS and their association with a less favourable stroke outcome, while treatment data are scarce.Overall, the evidence base is best for OSA relationship with stroke and supports active diagnosis and therapy. Research gaps remain especially regarding insomnia and RLS/PLMS relationships with stroke.

Management of Stroke in the Neurocritical Care Unit

PURPOSE OF REVIEW

This article provides updated information regarding the diagnosis and treatment (specifically critical care management) of acute ischemic stroke. This article also discusses the increased use of thrombolysis and thrombectomy in clinical practice.

RECENT FINDINGS

Stroke is the leading cause of disability in the United States. A significant proportion of patients with acute ischemic stroke require critical care management. Much has changed in the early evaluation and treatment of patients presenting with acute ischemic stroke. The introduction of embolectomy in large vessel occlusions for up to 24 hours post-symptom onset has resulted in one in every three eligible patients with acute ischemic stroke with the potential to lead an independent lifestyle. These patients increasingly require recognition of complications and initiation of appropriate interventions as well as earlier admission to dedicated neurocritical care units to ensure better outcomes.

SUMMARY

This article emphasizes issues related to the management of patients with acute ischemic stroke undergoing mechanical thrombectomy and thrombolysis and addresses the complex physiologic changes affecting neurologic and other organ systems.

Prevalence of sleep-disordered breathing after stroke and TIA: A meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis on the prevalence of sleep-disordered breathing (SDB) after stroke.

METHODS

We searched PubMed, Embase (Ovid), the Cochrane Library, and CINAHL (from their commencements to April 7, 2017) for clinical studies reporting prevalence and/or severity of SDB after stroke or TIA. Only sleep apnea tests performed with full polysomnography and diagnostic devices of the American Academy of Sleep Medicine categories I-IV were included. We conducted random-effects meta-analysis. PROSPERO registration number: CRD42017072339.

RESULTS

The initial search identified 5,211 publications. Eighty-nine studies (including 7,096 patients) met inclusion criteria. Fifty-four studies were performed in the acute phase after stroke (after less than 1 month), 23 studies in the subacute phase (after 1-3 months), and 12 studies in the chronic phase (after more than 3 months). Mean apnea-hypopnea index was 26.0/h (SD 21.7-31.2). Prevalence of SDB with apnea-hypopnea index greater than 5/h and greater than 30/h was found in 71% (95% confidence interval 66.6%-74.8%) and 30% (95% confidence interval 24.4%-35.5%) of patients, respectively. Severity and prevalence of SDB were similar in all examined phases after stroke, irrespective of the type of sleep apnea test performed. Heterogeneity between studies (I ²) was mostly high.

CONCLUSION

The high prevalence of SDB after stroke and TIA, which persists over time, is important in light of recent studies reporting the (1) feasibility and (2) efficacy of SDB treatment in this clinical setting.

CPAP as treatment of sleep apnea after stroke: A meta-analysis of randomized trials

OBJECTIVE

To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) examining the effectiveness of continuous positive airway pressure (CPAP) in stroke patients with sleep disordered breathing (SDB).

METHODS

In a systematic literature search of electronic databases (MEDLINE, Embase, and the Cochrane Library) from 1980 to November 2016, we identified RCTs that assessed CPAP compared to standard care or sham CPAP in adult patients with stroke or TIA with SDB. Mean CPAP use, odds ratios (ORs), and standardized mean differences (SMDs) were calculated. The prespecified outcomes were adherence to CPAP, neurologic improvement, adverse events, new vascular events, and death.

RESULTS

Ten RCTs (564 participants) with CPAP as intervention were included. Two studies compared CPAP with sham CPAP; 8 compared CPAP with usual care. Mean CPAP use across the trials was 4.53 hours per night (95% confidence interval [CI] 3.97-5.08). The OR of dropping out with CPAP was 1.83 (95% CI 1.05-3.21, p = 0.033). The combined analysis of the neurofunctional scales (NIH Stroke Scale and Canadian Neurological Scale) showed an overall neurofunctional improvement with CPAP (SMD 0.5406, 95% CI 0.0263-1.0548) but with a considerable heterogeneity (I² = 78.9%, p = 0.0394) across the studies. Long-term survival was improved with CPAP in 1 trial.

CONCLUSION

CPAP use after stroke is acceptable once the treatment is tolerated. The data indicate that CPAP might be beneficial for neurologic recovery, which justifies larger RCTs.

Impact of vagus nerve stimulation on sleep-related breathing disorders in adults with epilepsy

BACKGROUND

Vagus nerve stimulation (VNS) can induce a sleep apnea syndrome (SAS), which in turn can worsen seizure control and represents a cardiovascular risk factor. Epidemiology of VNS-induced SAS has received little attention to date. The purpose of this study was to estimate the VNS-induced SAS prevalence and to explore clinical variables potentially correlating with its development.

METHODS

We analyzed the computerized medical records of 18 consecutive adults treated for refractory epilepsy with VNS, implanted between May 2008 and October 2015. Patients underwent sleep polygraphy or polysomnography before and after VNS implantation. Between patients with and without SAS, we compared variables related to epilepsy type and device parameters.

RESULTS

Two patients had SAS and were treated before implantation; one improved after VNS, the other worsened. Four other patients developed SAS after VNS: induced/aggravated SAS occurred in 5/18 patients (prevalence: 27.8%). Only 2 of them had symptoms: one complained of important snoring, the other reported seizure worsening. All 5 patients were successfully treated by combinations of continuous positive airway pressure (cPAP), positional therapy, or VNS parameters modification. There was no statistically significant difference between potential predictors.

CONCLUSION

Despite the relatively modest clinical impact on epilepsy, in view of the associated cardiovascular risk factor development, easy treatment, and the relatively high SAS prevalence, routine screening for SAS before and after VNS implantation may represent a reasonable practice.