Effect of transnasal insufflation on sleep disordered breathing in acute stroke: a preliminary study

The effectiveness of supplemental oxygen and high-flow nasal cannula therapy in patients with obstructive sleep apnea in different clinical settings: A systematic review and meta-analysis

STUDY OBJECTIVE

To evaluate the effectiveness of supplemental oxygen therapy and high-flow nasal cannula (HFNC) therapy in patients with obstructive sleep apnea (OSA) in different clinical settings to assess its application to surgical patients in the postoperative setting.

DESIGN

A systematic search was conducted on MEDLINE and other databases from 1946 to December 16th, 2021. Title and abstract screening were conducted independently, and the lead investigators resolved conflicts. Meta-analyses were performed using a random-effects model and are presented as mean difference and standardized mean difference with 95% confidence intervals. These were calculated using RevMan 5.4.

PATIENTS

1395 and 228 OSA patients underwent oxygen therapy and HFNC therapy respectively.

INTERVENTIONS

Oxygen therapy and HFNC therapy.

MEASUREMENTS

Apnea-hypopnea index (AHI), oxyhemoglobin saturation (SpO₂), cumulative time with SPO₂ < 90% (CT90).

MAIN RESULTS

Twenty-seven oxygen therapy studies were included in the review, with ten randomized controlled trials (RCT), seven randomized crossovers, seven non-randomized crossovers, and three prospective cohorts. Pooled analyses showed that oxygen therapy significantly reduced AHI by 31% and increased SpO₂ by 5% versus baseline, and CPAP significantly reduced AHI by 84%, and increased SpO₂ by 3% versus baseline. CPAP was 53% more effective in reducing AHI than oxygen therapy, but both treatments had similar effectiveness in increasing SpO₂. Nine HFNC studies were included in the review, with five prospective cohorts, three randomized crossovers, and one RCT. Pooled analyses showed that HFNC therapy significantly reduced AHI by 36% but did not substantially increase SpO₂.

CONCLUSIONS

Oxygen therapy effectively reduces AHI and increases SpO₂ in patients with OSA. CPAP is more effective in reducing AHI than oxygen therapy. HFNC therapy is effective in reducing AHI. Although both oxygen therapy and HFNC therapy effectively reduce AHI, more research is needed to draw conclusions on clinical outcomes.

Combination therapy of high-flow nasal cannula and upper body elevation for postoperative sleep disordered breathing; randomized cross-over trial

BACKGROUND

Low acceptance rate of continuous positive airway pressure therapy in postoperative patients with untreated obstructive sleep apnea (OSA) indicates the necessity for development of an alternative postoperative airway management strategy. We considered whether the combination of high-flow nasal cannula and upper body elevation could improve postoperative OSA.

METHODS

This non-blinded randomized crossover study performed at a single university hospital investigated the effect on a modified apnea hypopnea index, based exclusively on the airflow signal without arterial oxygen saturation criteria (flow-based apnea hypopnea index, primary outcome), of high-flow nasal cannula (20 liter.minute-1 with 40% oxygen concentration) with and without upper body elevation in patients with moderate to severe OSA. Preoperative sleep studies were performed at home (control, no head-of-bed elevation) and in hospital (30-degree head-of-bed elevation). On the first and second postoperative nights, high-flow nasal cannula was applied with or without 30-degree head-of-bed elevation, assigned in random order to 23 eligible participants.

RESULTS

Twenty-two out of the 23 (96%) accepted high-flow nasal cannula. Four participants resigned from the study. Control flow-based apnea hypopnea index (mean±SD: 59.6 ± 12.0 events.hour-1, n=19) was reduced by 14.7 (95% CI: 5.5 to 30.0) events.hour-1 with head-of-bed elevation alone (p=0.002), 10.9 (1.2 to 20.6) events.hour-1 with high-flow nasal cannula alone (p=0.028), and 22.5 (13.1 to 31.9) events.hour-1 with combined head-of-bed elevation and high-flow nasal cannula (p<0.001). Compared to sole high-flow nasal cannula, additional intervention with head-of-bed elevation significantly decreased flow-based apnea hypopnea index by 11.5 events.hour-1 (1.7 to 21.4) (p=0.022). High-flow nasal cannula, alone or in combination with head-of-bed elevation also improved overnight oxygenation. No harmful events were observed.

CONCLUSION

The combination of high-flow nasal cannula and upper body elevation reduced OSA severity and nocturnal hypoxemia, suggesting a role for it as an alternate postoperative airway management strategy.

High-flow nasal cannula ventilation therapy for obstructive sleep apnea in ischemic stroke patients requiring nasogastric tube feeding: a preliminary study

Obstructive sleep apnea (OSA) is associated with increasing risk of recurrent stroke and mortality. Nasogastric tubes used by dysphagic stroke patients may interfere with nasal continuous positive airway pressure (CPAP) due to air leakage. This study was evaluated the effects and short-term tolerability of high-flow nasal cannula (HFNC) therapy for OSA in stroke patients with nasogastric intubation. The HFNC titration study was performed in post-acute ischemic stroke patients with nasogastric intubation and OSA. Then, participants were treated with HFNC therapy in the ward for one week. Eleven participants (eight males) who were all elderly with a median age of 72 (IQR 67–82) years and a body mass index of 23.5 (IQR 22.0–26.6) completed the titration study. The HFNC therapy at a flow rate up to 50~60 L/min significantly decreased the apnea-hypopnea index from 52.0 events/h (IQR 29.9–61.9) to 26.5 events/h (IQR 3.3–34.6) and the total arousal index from 34.6 (IQR 18.6–42.3) to 15.0 (IQR 10.3–25.4). The oxygen desaturation index was also significantly decreased from 53.0 events/h (IQR 37.0–72.8) to 16.2 events/h (IQR 0.8–20.1), accompanied by a significant improvement in the minimum SpO₂ level. Finally, only three participants tolerated flow rates of 50~60 L/minute in one-week treatment period. Conclusively, HFNC therapy at therapeutic flow rate is effective at reducing the OSA severity in post-acute ischemic stroke patients with nasogastric intubation. Owing to the suboptimal acceptance, HFNC might be a temporary treatment option, and CPAP therapy is suggested after the nasogastric tube is removed.

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.

Severely Disturbed Sleep in Patients With Acute Ischemic Stroke on Stroke Units: A Pilot Study

Introduction: Previous studies revealed a high prevalence of sleep-wake disturbances in subacute and chronic stroke. We analyzed sleep quantity and quality in patients with hyperacute ischemic stroke on stroke units.

Methods: We categorized sleep stages as N1, N2, N3, and REM according to the 2017 criteria of the American Academy of Sleep Medicine in 23 continuous, overnight EEG registrations from 18 patients, starting within 48 h since the onset of cortical ischemic stroke. Associations between presence and duration of sleep stages, and secondary deterioration or functional outcome were analyzed.

Results: Physiological sleep cycles were seen in none of the patients. Otherwise, sleep stages alternated chaotically, both during day- and during nighttime, with a sleep efficiency of 30% and 10.5 ± 4.4 (mean ± SD) awakenings per hour of sleep. We cannot differentiate between stroke related and external factors. Only few interruptions could be related to planned nightly wake up calls, but turbulence on stroke units may have played a role. Six patients (seven nights) did not reach deep sleep (N3), 10 patients (13 nights) did not reach REM sleep. If reached, the mean durations of deep and REM sleep were short, with 37 (standard deviation (SD) 25) and 18 (SD15) minutes, respectively. Patients with secondary deterioration more often lacked deep sleep (N3) than patients without secondary deterioration [4 (57%) vs. 2 (25%)], but without statistical significance (p = 0.12).

Conclusion: We show that sleep is severely disturbed in patients with acute ischemic stroke admitted to stroke units. Larger studies are needed to clarify associations between deprivation of deep sleep and secondary deterioration.

Oxygen for the treatment of obstructive sleep apnoea hypopnoea syndrome

Oxygen, in the form of diatomic oxygen (O₂), comprises 20.8% of the Earth's atmosphere and is essential to most life forms on the planet. In 1777, Lavoisier was the first to name oxygen and recognise that it was a chemical element involved in combustion.

Nocturnal oxygen therapy cannot currently be recommended as a sole treatment for obstructive sleep apnoeahttp://bit.ly/2kuAsPU

The Evolution of Sleep Apnea Six Months After Acute Ischemic Stroke and Thrombolysis

STUDY OBJECTIVES

Our goal was to investigate the evolution of prevalence, severity, and type of sleep apnea among patients who had an ischemic stroke, with or without treatment with thrombolysis after 6 months.

METHODS

We prospectively studied 204 patients who had an ischemic stroke (110 in the thrombolysis and 94 in the non-thrombolysis group). After follow-up, 177 patients were eligible for a final analysis (98 in the thrombolysis group and 79 in the non-thrombolysis group). An unattended sleep study with a three-channel portable device was performed both on admission and after the 6-month follow-up.

RESULTS

The patients receiving thrombolysis were younger than those in the non-thrombolysis group (mean 65.5 versus 69.6 years P = .039). Sleep apnea, defined as a respiratory event index (REI) ≥ 5 events/h, was diagnosed in 92.7% patients, 93.9% versus 91.1% (P = .488) in the thrombolysis and non-thrombolysis groups, respectively. The prevalence remained unchanged during follow-up. Mild sleep apnea progressed to moderate or severe sleep apnea in 69.2% of the patients. Globally, mean central apneas per hour increased by 2.2% (P = .002), whereas obstructive apneas declined by 1.7% (P = .014). The mean change of oxygen desaturation index was -6.1% (P < .001) in the thrombolysis group, -1.8% (P = .327) in the non-thrombolysis group, and 4.2% (P = .001) in the whole group. In the non-thrombolysis group, the risk for new sleep apnea incidence increased by 6.1-fold (P = .024) at follow-up when compared to the thrombolysis group.

CONCLUSIONS

Sleep apnea prevalence remained high in patients who had an ischemic stroke at 6 months post-stroke. The risk for developing sleep apnea after stroke was significantly lower among patients undergoing thrombolysis.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Ischaemic Stroke and Sleep Apnea in Northern Part of Finland; Identifier: NCT01861275; URL: https://clinicaltrials.gov/ct2/show/NCT01861275.

Role of sleep-disordered breathing and sleep-wake disturbances for stroke and stroke recovery

Background:

Sleep-disordered breathing (SDB) and sleep-wake disturbances (SWD) are highly prevalent in stroke patients. Recent studies suggest that they represent both a risk factor and a consequence of stroke and affect stroke recovery, outcome, and recurrence.

Methods:

Review of literature.

Results:

Several studies have proven SDB to represent an independent risk factor for stroke. Sleep studies in TIA and stroke patients are recommended in view of the very high prevalence (>50%) of SDB (Class IIb, level of evidence B). Treatment of obstructive SDB with continuous positive airway pressure is recommended given the strength of the increasing evidence in support of a positive effect on outcome (Class IIb, level of evidence B). Oxygen, biphasic positive airway pressure, and adaptive servoventilation may be considered in patients with central SDB. Recently, both reduced and increased sleep duration, as well as hypersomnia, insomnia, and restless legs syndrome (RLS), were also suggested to increase stroke risk. Mainly experimental studies found that SWD may in addition impair neuroplasticity processes and functional stroke recovery. Treatment of SWD with hypnotics and sedative antidepressants (insomnia), activating antidepressants or stimulants (hypersomnia), dopaminergic drugs (RLS), and clonazepam (parasomnias) are based on single case observations and should be used with caution.

Conclusions:

SDB and SWD increase the risk of stroke in the general population and affect short- and long-term stroke recovery and outcome. Current knowledge supports the systematic implementation of clinical procedures for the diagnosis and treatment of poststroke SDB and SWD on stroke units.

Current evidence for the effectiveness of heated and humidified high flow nasal cannula supportive therapy in adult patients with respiratory failure

High flow nasal cannula (HFNC) supportive therapy has emerged as a safe, useful therapy in patients with respiratory failure, improving oxygenation and comfort. Recently several clinical trials have analyzed the effectiveness of HFNC therapy in different clinical situations and have reported promising results. Here we review the current knowledge about HFNC therapy, from its mechanisms of action to its effects on outcomes in different clinical situations.

Nasal insufflation treatment adherence in obstructive sleep apnea

BACKGROUND

Nasal insufflation (NI) is a novel treatment method that has been introduced for improving respiration during sleep. NI’s warmed and humidified nasal airflow provides ventilatory assistance delivered as a rapidly dispersed pressure head, with minimal side wall pressures, that may affect treatment tolerability. The aim of the current study was to investigate objective and subjective adherence rates for NI therapy in mild to moderate obstructive sleep apnea (OSA).

METHODS

Ten patients (three men and seven women; age, 51.3 ± 9.6 years; BMI, 32.2 ± 7.7 kg/m2 [mean ± sd]) with recently diagnosed mild to moderate OSA (10.9 ± 5.8 events/h) were investigated. A crossover design was used to compare adherence to NI and continuous positive airway pressure (CPAP) therapy using a range of objective and subjective measurements. Objective (sleep efficiency (%) and arousal indices (arousal/h)) and subjective evaluations of sleep quality were carried out each night in the laboratory. During in-home treatment, adherence for both therapies was assessed objectively (time on therapy) and subjectively (self-reported sleep diary).

RESULTS

Objectively derived adherence values were comparable for CPAP and NI, with both treatment devices sharing similar usage per night (3.5 ± 2.5 vs. 3.6 ± 1.6 h/night; respectively) and the number of nights with at least 4 h of treatment (5.5 ± 4.3 vs. 6.8 ± 3.3 nights/trial, respectively). Self-reported adherence was significantly higher than objectively assessed adherence (p < 0.03).

CONCLUSIONS

This study showed similar adherence to NI and CPAP over a short period of usage. A randomized clinical trial is now essential for determining the comparative effectiveness of NI therapy in relation to treatment with CPAP.

High-flow nasal cannula oxygen therapy in adults

High-flow nasal cannula (HFNC) oxygen therapy comprises an air/oxygen blender, an active humidifier, a single heated circuit, and a nasal cannula. It delivers adequately heated and humidified medical gas at up to 60 L/min of flow and is considered to have a number of physiological effects: reduction of anatomical dead space, PEEP effect, constant fraction of inspired oxygen, and good humidification. While there have been no big randomized clinical trials, it has been gaining attention as an innovative respiratory support for critically ill patients. Most of the available data has been published in the neonatal field. Evidence with critically ill adults are poor; however, physicians apply it to a variety of patients with diverse underlying diseases: hypoxemic respiratory failure, acute exacerbation of chronic obstructive pulmonary disease, post-extubation, pre-intubation oxygenation, sleep apnea, acute heart failure, patients with do-not-intubate order, and so on. Many published reports suggest that HFNC decreases breathing frequency and work of breathing and reduces needs of escalation of respiratory support in patients with diverse underlying diseases. Some important issues remain to be resolved, such as its indication, timing of starting and stopping HFNC, and escalating treatment. Despite these issues, HFNC oxygen therapy is an innovative and effective modality for the early treatment of adults with respiratory failure with diverse underlying diseases.