Metrology of two wearable sleep trackers against polysomnography in patients with sleep complaints.

Sleep trackers are used widely by patients with sleep complaints, however their metrological validation is often poor and relies on healthy subjects. We assessed the metrological validity of two commercially available sleep trackers (Withings Activité/Fitbit Alta HR) through a prospective observational monocentric study, in adult patients referred for polysomnography (PSG). We compared the total sleep time (TST), REM time, REM latency, nonREM1 + 2 time, nonREM3 time, and wake after sleep onset (WASO). We report absolute and relative errors, Bland-Altman representations, and a contingency table of times spent in sleep stages with respect to PSG. Sixty-five patients were included (final sample size 58 for Withings and 52 for Fitbit). Both devices gave a relatively accurate sleep start time with a median absolute error of 5 (IQR -43; 27) min for Withings and -2.0 (-12.5; 4.2) min for Fitbit but both overestimated TST. Withings tended to underestimate WASO with a median absolute error of -25.0 (-61.5; -8.5) min, while Fitbit tended to overestimate it (median absolute error 10 (-18; 43) min. Withings underestimated light sleep and overestimated deep sleep, while Fitbit overestimated light and REM sleep and underestimated deep sleep. The overall kappas for concordance of each epoch between PSG and devices were low: 0.12 (95%CI 0.117-0.121) for Withings and VPSG indications 0.07 (95%CI 0.067-0.071) for Fitbit, as well as kappas for each VPSG indication 0.07 (95%CI 0.067-0.071). Thus, commercially available sleep trackers are not reliable for sleep architecture in patients with sleep complaints/pathologies and should not replace actigraphy and/or PSG.

Simplified frontal EEG in adults under veno-arterial extracorporeal membrane oxygenation.

BACKGROUND: EEG-based prognostication studies in intensive care units often rely on a standard 21-electrode montage (stdEEG) requiring substantial human, technical, and financial resources. We here evaluate whether a simplified 4-frontal electrode montage (4-frontEEG) can detect EEG patterns associated with poor outcomes in adult patients under veno-arterial extracorporeal membrane oxygenation (VA-ECMO). METHODS: We conducted a reanalysis of EEG data from a prospective cohort on 118 adult patients under VA-ECMO, in whom EEG was performed on admission to intensive care. EEG patterns of interest included background rhythm, discontinuity, reactivity, and the Synek's score. They were all reassessed by an intensivist on a 4-frontEEG montage, whose analysis was then compared to an expert's interpretation made on stdEEG recordings. The main outcome measure was the degree of correlation between 4-frontEEG and stdEEG montages to identify EEG patterns of interest. The performance of the Synek scores calculated on 4-frontEEG and stdEEG montage to predict outcomes (i.e., 28-day mortality and 90-day Rankin score [Formula: see text]) was investigated in a secondary exploratory analysis. RESULTS: The detection of EEG patterns using 4-frontEEG was statistically similar to that of stdEEG for background rhythm (Spearman rank test, ρ = 0.66, p < 0.001), discontinuity (Cohen's kappa, [Formula: see text] = 0.955), reactivity ([Formula: see text] = 0.739) and the Synek's score (ρ = 0.794, p < 0.001). Using the Synek classification, we found similar performances between 4-frontEEG and stdEEG montages in predicting 28-day mortality (AUC 4-frontEEG 0.71, AUC stdEEG 0.68) and for 90-day poor neurologic outcome (AUC 4-frontEEG 0.71, AUC stdEEG 0.66). An exploratory analysis confirmed that the Synek scores determined by 4 or 21 electrodes were independently associated with 28-day mortality and poor 90-day functional outcome. CONCLUSION: In adult patients under VA-ECMO, a simplified 4-frontal electrode EEG montage interpreted by an intensivist, detected common EEG patterns associated with poor outcomes, with a performance similar to that of a standard EEG montage interpreted by expert neurophysiologists. This simplified montage could be implemented as part of a multimodal evaluation for bedside prognostication.

Association of Standard Electroencephalography Findings With Mortality and Command Following in Mechanically Ventilated Patients Remaining Unresponsive After Sedation Interruption.

CONTEXT: Delayed awakening after sedation interruption is frequent in critically ill patients receiving mechanical ventilation. OBJECTIVES: We aimed to investigate the association of standard electroencephalography with mortality and command following in this setting. DESIGN, SETTING, AND PATIENTS: In a single-center study, we retrospectively analyzed standard electroencephalography performed in consecutive mechanically ventilated patients remaining unresponsive (comatose/stuporous or unable to follow commands) after sedation interruption. Standard electroencephalography parameters (background activity, continuity, and reactivity) were reassessed by neurophysiologists, blinded to patients' outcome. Patients were categorized during follow-up into three groups based on their best examination as: 1) command following, 2) unresponsive, or 3) deceased. Cause-specific models were used to identify independent standard electroencephalography parameters associated with main outcomes, that is, mortality and command following. Follow-up was right-censored 30 days after standard electroencephalography. MEASUREMENTS AND MAIN RESULTS: Main standard electroencephalography parameters recorded in 121 unresponsive patients (median time between sedation interruption and standard electroencephalography: 2 d [interquartile range, 1-4 d]) consisted of a background frequency greater than 4 Hz in 71 (59%), a discontinuous background in 19 (16%), and a preserved reactivity in 98/120 (82%) patients. At 30 days, 66 patients (55%) were command following, nine (7%) were unresponsive, and 46 (38%) had died. In a multivariate analysis adjusted for nonneurologic organ failure, a reactive standard electroencephalography with a background frequency greater than 4 Hz was independently associated with a reduced risk of death (cause-specific hazard ratio, 0.38; CI 95%, 0.16-0.9). By contrast, none of the standard electroencephalography parameters were independently associated with command following. Sensitivity analyses conducted after exclusion of 29 patients with hypoxic brain injury revealed similar findings. CONCLUSIONS: In patients remaining unresponsive after sedation interruption, a pattern consisting of a reactive standard electroencephalography with a background frequency greater than 4 Hz was associated with decreased odds of death. None of the standard electroencephalography parameters were independently associated with command following.

Early EEG for Prognostication Under Venoarterial Extracorporeal Membrane Oxygenation.

BACKGROUND/OBJECTIVES: Tools for prognostication of neurologic outcome of adult patients under venoarterial ECMO (VA-ECMO) have not been thoroughly investigated. We aimed to determine whether early standard electroencephalography (stdEEG) can be used for prognostication in adults under VA-ECMO. METHODS: Prospective single-center observational study conducted in two intensive care units of a university hospital, Paris, France. Early stdEEG was performed on consecutive adult patients treated with VA-ECMO for refractory cardiogenic shock or refractory cardiac arrest. The association between stdEEG findings and unfavorable outcome was investigated. The primary endpoint was 28-day mortality. The secondary endpoint was severe disability or death at 90 days, defined by a score of 4-6 on the modified Rankin scale. RESULTS: A total of 122 patients were included, of whom 35 (29%) received cardiopulmonary resuscitation before VA-ECMO cannulation. Main stdEEG findings included low background frequency ≤ 4 Hz (n = 27, 22%) and background abnormalities, i.e., a discontinuous (n = 20, 17%) and/or an unreactive background (n = 12, 10%). Background abnormalities displayed better performances for prediction of unfavorable outcomes, as compared to clinical parameters at time of recording. An unreactive stdEEG background in combination with a background frequency ≤ 4 Hz had a false positive rate of 0% for prediction of unfavorable outcome at 28 days and 90 days, with sensitivities of 8% and 6%, respectively. After adjustment for confounders, a lower background frequency was independently associated with unfavorable outcome at 28 days (adjusted odds ratio per 1-Hz increment, 95% CI 0.71, 0.52-0.97), whereas no such independent association was observed at 90 days. CONCLUSION: Standard EEG abnormalities recorded at time of VA-ECMO initiation are predictive of unfavorable outcomes. However, the low sensitivity of these parameters highlights the need for a multimodal evaluation for improving management of care and prognostication.

Early Electroencephalography Findings in Cardiogenic Shock Patients Treated by Venoarterial Extracorporeal Membrane Oxygenation.

OBJECTIVES: We aimed to assess early electroencephalography findings in patients treated by venoarterial extracorporeal membrane oxygenation and their association with neurologic outcome. DESIGN: Single-center observational study. SETTING: Medical ICU of a university hospital. PATIENTS: An early standardized electroencephalography assessment, that is, standard electroencephalography followed by continuous electroencephalography, was performed in consecutive cardiogenic shock patients requiring venoarterial extracorporeal membrane oxygenation. Associations between electroencephalography findings and outcome, defined as a composite of acute brain injury or death at 14 days, were investigated. MEASUREMENTS AND MAIN RESULTS: Twenty-two patients with a median Full Outline of Unresponsiveness score of 4 (interquartile range, 3-6) were studied. Pupillary light reflex, corneal reflex, and cough reflex were preserved in 20 (90%), 17 (77%), and 17 (77%) patients, respectively. Overall, standard electroencephalography findings consisted of diffuse slowing in 21 patients (95%) and severe background abnormalities in 13 patients (59%) (i.e., a discontinuous [n = 5; 23%] and/or an unreactive background [n = 9; 41%]). Severe background abnormalities on standard electroencephalography (poor outcome rate: 69% vs 22%; p = 0.03) and absence of sleep transients on continuous electroencephalography (poor outcome rate: 67% vs 14%; p = 0.02) were associated with a poor outcome, whereas neurologic findings and doses of sedation were not. Patients without sleep transients on continuous electroencephalography tended to have lower Full Outline of Unresponsiveness scores than patients with preserved sleep transients-appearing patterns. CONCLUSIONS: In patients treated by venoarterial extracorporeal membrane oxygenation, early severe background abnormalities on standard electroencephalography provide important information on neurologic outcome. The lack of sleep transients on continuous electroencephalography reflects the severity of brain dysfunction and might represent an additional prognostic marker.

Orthostatic hypotension: A review.

Orthostatic hypotension, defined by a drop in blood pressure of at least 20mmHg for systolic blood pressure and at least 10mmHg for diastolic blood pressure within 3minutes of standing up, is a frequent finding, particularly in elderly patients. It is associated with a significant increase in morbidity and mortality. Although it is often multifactorial, the first favoring factor is medications. Other etiologies are divided in neurogenic orthostatic hypotension, characterized by autonomic failure due to central or peripheral nervous system disorders, and non-neurogenic orthostatic hypotension, mainly favoured by hypovolemia. Treatment always requires education of the patient regarding triggering situations and physiological countermanoeuvers. Pharmacological treatment may sometimes be necessary and mainly relies on volume expansion by fludrocortisone and/or a vasopressor agents such as midodrine. There is no predefined blood pressure target, the goal of therapy being the relief of symptoms and fall prevention.

[Central sleep apnoea syndrome]. / Syndrome d'apnées centrales du sommeil.

In central sleep apnoea syndrome (SAS), there is a dysfunction in central ventilatory command. Patients with central SAS can exhibit symptoms and complications linked to unstable sleep caused by apnoea and certain specific mechanisms (chronic and intermittent hypoxia). Central SAS is linked to several diseases which should be investigated before treatment. Treatment depends on underlying conditions and should focus on alleviating symptoms. Possible treatments include nocturnal non invasive ventilation and/or oxygen, and oral medications. Chronic heart failure with LVEF<45% is a contraindication to servo-assisted ventilation. Several observational French studies are currently enrolling patients to gain knowledge on disease and the impact of treatment.