Effectiveness of Angiotensin II for Catecholamine Refractory Septic or Distributive Shock on Mortality: A Propensity Score Weighted Analysis of Real-World Experience in the Medical ICU.

Angiotensin II (ATII) was approved for septic or other distributive shock due to its property of increasing blood pressure within 3 hours. Limited data exist regarding its effectiveness when used in real-world clinical practice. OBJECTIVES: This study examined ATII as a third-line vasopressor based on institutional approval. DESIGN: Retrospective observational cohort study. SETTING AND PARTICIPANTS: Medical ICU at an academic tertiary care medical center. Adult patients requiring 3 or more vasopressor agents for septic shock or other forms of distributed shock from September 1, 2018, to January 31, 2020. MAIN OUTCOMES AND MEASURES: Effect of ATII after norepinephrine and vasopressin on mortality and mean arterial blood pressure response after 3 hours of administration. RESULTS: One-hundred forty-seven patients, 56 receiving ATII and 91 receiving another vasopressor (non-ATII), were enrolled. Patients in the ATII group had higher mortality compared to the non-ATII group, and more required 5 or greater vasopressor agents (p < 0.01). After propensity score weighting, there remains a trend in higher mortality in the ATII compared to non-ATII group, but not statistically significant (86.0% vs 71.0%, p = 0.16). More patients in the ATII group continued to require 5 or greater vasopressor agents compared to the non-ATII group after propensity score weighting (45.9% vs 12.5%, p < 0.01). SOFA score was the only variable associated with mortality (OR = 1.25, 95% CI, 1.05-1.49; p = 0.01). Patients were considered a "responder" if mean arterial pressure greater than 65 mm Hg at 3 hours after the third vasopressor was initiated. Among the ATII group, 37.5% patients were responders compared to 45.1% responders in the non-ATII group (relative risk = 1.07, 95% CI, 0.6-1.93; p = 0.81). CONCLUSIONS AND RELEVANCE: Although previous data support the use of ATII due to its favorable hemodynamic response in patients with distributive shock, there was no observed benefit in mortality or hemodynamic response with ATII as a third-line vasopressor in our study of real-world patients.

A Reassessment of Weaning Parameters in Patients With Spontaneous Intracerebral Hemorrhage.

Background and purpose Patients with spontaneous intracerebral haemorrhage have significant morbidity and mortality. One aspect of their care is the need for mechanical ventilation. Extubating a patient safely and efficiently is important in advancing their care; however, traditional extubation criteria using the rapid shallow breathing index and negative inspiratory force do not predict success in these patients as well as they do in other intubated patients. This study aimed to evaluate these criteria in patients with spontaneous intracerebral haemorrhage to improve the extubation success rate. Methods We conducted a retrospective chart review of patients with spontaneous intracerebral haemorrhage (sICH) who underwent spontaneous breathing trials from 2018 to 2020. Twenty-nine patients met the inclusion criteria, and of these 29, 20 had a trial of extubation. Rapid shallow breathing index (RSBI), negative inspiratory force (NIF), and cuff leak were recorded to analyze breathing parameters at the time of extubation. Patients who required reintubation were noted. Results All trials of extubation required a cuff leak. Using RSBI, patients with values <105 or <85, as the only other extubation criteria, were associated with a 70.6% and 71.4% success rate, respectively. With RSBI <105 and NIF <-25 cm water, the success rate was 88.9%. Any patient with a cuff leak that had a NIF <-30 had a success rate of 100%, regardless of RSBI. Conclusion The RSBI was not a reliable isolated measure to predict 100% extubation success. Using a NIF <-30 predicts a 100% extubation success rate if a cuff leak is present. This demonstrates that the NIF may be a more useful metric in sICH patients, as it accounts for patient participation and innate ability to draw a breath spontaneously. Future studies are warranted to evaluate further and optimize the extubation criteria in these patients.

Effect of electrocardiographic contamination on surface electromyography assessment of back muscles.

The purpose of this study was to demonstrate the relative effect of electrocardiography (ECG) on back muscle surface electromyography (SEMG) parameters and their corresponding sensitivity in low back pain (LBP) assessment. Back muscle SEMG activities were recorded from 17 healthy subjects and 18 chronic LBP patients under static postures (straight sitting and upright standing), and dynamic action (flexion-extension). ECG cancellation based on independent component analysis (ICA) method was performed. Root mean square (RMS) and median frequency (MF) of raw and denoised SEMG data were computed respectively. Multiple comparisons were then performed. A consistent trend of change (increased MF and decreased RMS) followed ECG removal was noticed. In particular, in SEMG measurements under static postures, a significant decrease in RMS (p<0.05) and increase in MF (p<0.05) were found in all recording muscle groups. Level of corruption by ECG artifacts on SEMG measurements was found to be more serious and prominent in static postures than that in dynamic action. After ECG removal, significant improvements in the ability of SEMG to discriminate LBP patients from healthy subjects were seen in RMS amplitude recorded while standing (p<0.05) and MF in all measuring conditions (p<0.05). This study provides a more complete understanding on the relative effect of ECG contamination on back muscles SEMG parameters and LBP assessment.

Quality of life of traumatic spinal cord injured patients in Hong Kong.

OBJECTIVE: To assess the health-related quality of life of patients with traumatic spinal cord injury living in Hong Kong. DESIGN: A cross-sectional retrospective study. SUBJECTS: Subjects with paraplegia following traumatic spinal cord injury were recruited from our department, which is one of the 3 main regional spinal cord injury rehabilitation centres in Hong Kong. A total of 120 potential participants were invited to join the study. The final study group comprised 58 patients (25 (43%) men and 33 (57%) women, 30 (50%) of whom were under 40 years of age). METHODS: Health-related quality of life was assessed using the Hong Kong Chinese version of the World Health Organization Quality of Life Measure Abbreviated version (WHO-QOL-BREF(HK)). Results were summarized and compared with previous results from healthy and other disease populations in Hong Kong. RESULTS: There was no significant difference in quality of life between men and women, or between different durations of spinal cord injury, different educational levels or different marital status (p > 0.05). However, a significant difference in quality of life was found in different age groups and between people with incomplete and complete paraplegia (p < 0.05). Compared with healthy and other disease populations, people with paraplegia had the lowest quality of life in Hong Kong (p < 0.001). CONCLUSION: People with paraplegia in Hong Kong have a lower quality of life than the general Hong Kong population. More community support is required to meet the needs of these patients in the areas of transportation, medical care and social life, in particular.

An evaluation of mental workload with frontal EEG.

Using a wireless single channel EEG device, we investigated the feasibility of using short-term frontal EEG as a means to evaluate the dynamic changes of mental workload. Frontal EEG signals were recorded from twenty healthy subjects performing four cognitive and motor tasks, including arithmetic operation, finger tapping, mental rotation and lexical decision task. Our findings revealed that theta activity is the common EEG feature that increases with difficulty across four tasks. Meanwhile, with a short-time analysis window, the level of mental workload could be classified from EEG features with 65%-75% accuracy across subjects using a SVM model. These findings suggest that frontal EEG could be used for evaluating the dynamic changes of mental workload.

Cross-frequency information transfer from EEG to EMG in grasping.

This paper presents an investigation into the cortico-muscular relationship during a grasping task by evaluating the information transfer between EEG and EMG signals. Information transfer was computed via a non-linear model-free measure, transfer entropy (TE). To examine the cross-frequency interaction, TEs were computed after the times series were decomposed into various frequency ranges via wavelet transform. Our results demonstrate the capability of TE to capture the direct interaction between EEG and EMG. In addition, the cross-frequency analysis revealed instantaneous decrease in information transfer from EEG to the high frequency component of EMG (100-200Hz) during the onset of movement.

P300-based brain-computer interface (BCI) event-related potentials (ERPs): People with amyotrophic lateral sclerosis (ALS) vs. age-matched controls.

OBJECTIVE: Brain-computer interfaces (BCIs) aimed at restoring communication to people with severe neuromuscular disabilities often use event-related potentials (ERPs) in scalp-recorded EEG activity. Up to the present, most research and development in this area has been done in the laboratory with young healthy control subjects. In order to facilitate the development of BCI most useful to people with disabilities, the present study set out to: (1) determine whether people with amyotrophic lateral sclerosis (ALS) and healthy, age-matched volunteers (HVs) differ in the speed and accuracy of their ERP-based BCI use; (2) compare the ERP characteristics of these two groups; and (3) identify ERP-related factors that might enable improvement in BCI performance for people with disabilities. METHODS: Sixteen EEG channels were recorded while people with ALS or healthy age-matched volunteers (HVs) used a P300-based BCI. The subjects with ALS had little or no remaining useful motor control (mean ALS Functional Rating Scale-Revised 9.4 (±9.5SD) (range 0-25)). Each subject attended to a target item as the items in a 6×6 visual matrix flashed. The BCI used a stepwise linear discriminant function (SWLDA) to determine the item the user wished to select (i.e., the target item). Offline analyses assessed the latencies, amplitudes, and locations of ERPs to the target and non-target items for people with ALS and age-matched control subjects. RESULTS: BCI accuracy and communication rate did not differ significantly between ALS users and HVs. Although ERP morphology was similar for the two groups, their target ERPs differed significantly in the location and amplitude of the late positivity (P300), the amplitude of the early negativity (N200), and the latency of the late negativity (LN). CONCLUSIONS: The differences in target ERP components between people with ALS and age-matched HVs are consistent with the growing recognition that ALS may affect cortical function. The development of BCIs for use by this population may begin with studies in HVs but also needs to include studies in people with ALS. Their differences in ERP components may affect the selection of electrode montages, and might also affect the selection of presentation parameters (e.g., matrix design, stimulation rate). SIGNIFICANCE: P300-based BCI performance in people severely disabled by ALS is similar to that of age-matched control subjects. At the same time, their ERP components differ to some degree from those of controls. Attention to these differences could contribute to the development of BCIs useful to those with ALS and possibly to others with severe neuromuscular disabilities.

Spectral modulation of frontal EEG during motor skill acquisition: a mobile EEG study.

This study investigates the modulation of frontal EEG dynamics with respect to progress in motor skill acquisition using a wireless EEG system with a single dry sensor. Participants were required to complete repeated trials of a computerized visual-motor task similar to mirror drawing while the EEG was collected. In each trial, task performance of the participants was summarized with a familiarity index which took into account the performance accuracy, completion rate and time. Our findings demonstrated that certain EEG power spectra decreased with an increase in motor task familiarity. In particular, frontal EEG activities in delta and theta bands of the whole trial and in gamma band in the middle of the trial are having a significant negative relationship with the overall familiarity level of the task. The findings suggest that frontal EEG spectra are significantly modulated during motor skill acquisition. Results of this study shed light on the possibility of simultaneous monitoring of brain activity during an unconstrained natural task with a single dry sensor mobile EEG in an everyday environment.

Brain-computer interface (BCI) evaluation in people with amyotrophic lateral sclerosis.

Brain-computer interfaces (BCIs) might restore communication to people severely disabled by amyotrophic lateral sclerosis (ALS) or other disorders. We sought to: 1) define a protocol for determining whether a person with ALS can use a visual P300-based BCI; 2) determine what proportion of this population can use the BCI; and 3) identify factors affecting BCI performance. Twenty-five individuals with ALS completed an evaluation protocol using a standard 6 × 6 matrix and parameters selected by stepwise linear discrimination. With an 8-channel EEG montage, the subjects fell into two groups in BCI accuracy (chance accuracy 3%). Seventeen averaged 92 (± 3)% (range 71-100%), which is adequate for communication (G70 group). Eight averaged 12 (± 6)% (range 0-36%), inadequate for communication (L40 subject group). Performance did not correlate with disability: 11/17 (65%) of G70 subjects were severely disabled (i.e. ALSFRS-R < 5). All L40 subjects had visual impairments (e.g. nystagmus, diplopia, ptosis). P300 was larger and more anterior in G70 subjects. A 16-channel montage did not significantly improve accuracy. In conclusion, most people severely disabled by ALS could use a visual P300-based BCI for communication. In those who could not, visual impairment was the principal obstacle. For these individuals, auditory P300-based BCIs might be effective.

Spectral modulation of frontal EEG activities during motor skill acquisition: task familiarity monitoring using single-channel EEG.

This study investigates the modulation of frontal EEG dynamics with respect to progress in motor learning. Using a computerized visual-motor task similar to mirror drawing, our work demonstrated that overall EEG activities in all frequency bands decreased with an increase in motor task familiarity. In particular, frontal EEG activities in delta band of the whole trial and gamma band at the beginning of each trial are having a significant negative relationship with the overall familiarity level of the task. The findings suggest that frontal EEG spectra are significantly modulated during motor skill acquisition.