Intensive care management of acute stroke: general management

Radar-Based Heart Sound Detection

This paper introduces heart sound detection by radar systems, which enables touch-free and continuous monitoring of heart sounds. The proposed measurement principle entails two enhancements in modern vital sign monitoring. First, common touch-based auscultation with a phonocardiograph can be simplified by using biomedical radar systems. Second, detecting heart sounds offers a further feasibility in radar-based heartbeat monitoring. To analyse the performance of the proposed measurement principle, 9930 seconds of eleven persons-under-tests’ vital signs were acquired and stored in a database using multiple, synchronised sensors: a continuous wave radar system, a phonocardiograph (PCG), an electrocardiograph (ECG), and a temperature-based respiration sensor. A hidden semi-Markov model is utilised to detect the heart sounds in the phonocardiograph and radar data and additionally, an advanced template matching (ATM) algorithm is used for state-of-the-art radar-based heartbeat detection. The feasibility of the proposed measurement principle is shown by a morphology analysis between the data acquired by radar and PCG for the dominant heart sounds S1 and S2: The correlation is 82.97 ± 11.15% for 5274 used occurrences of S1 and 80.72 ± 12.16% for 5277 used occurrences of S2. The performance of the proposed detection method is evaluated by comparing the F-scores for radar and PCG-based heart sound detection with ECG as reference: Achieving an F1 value of 92.22 ± 2.07%, the radar system approximates the score of 94.15 ± 1.61% for the PCG. The accuracy regarding the detection timing of heartbeat occurrences is analysed by means of the root-mean-square error: In comparison to the ATM algorithm (144.9 ms) and the PCG-based variant (59.4 ms), the proposed method has the lowest error value (44.2 ms). Based on these results, utilising the detected heart sounds considerably improves radar-based heartbeat monitoring, while the achieved performance is also competitive to phonocardiography.

Malignant hemispheric infarction of the middle cerebral artery. Diagnostic considerations and treatment options

INTRODUCTION

Malignant hemispheric infarction (MHI) is a specific and devastating type of ischemic stroke. It usually affects all or part of the territory of the middle cerebral artery although its effects may extend to other territories as well. Its clinical outcome is frequently catastrophic when only conventional medical treatment is applied.

OBJECTIVE

The purpose of this review is to analyse the available scientific evidence on the treatment of this entity.

DEVELOPMENT

MHI is associated with high morbidity and mortality. Its clinical characteristics are early neurological deterioration and severe hemispheric syndrome. Its hallmark is the development of space-occupying cerebral oedema between day 1 and day 3 after symptom onset. The mass effect causes displacement, distortion, and herniation of brain structures even when intracranial hypertension is initially absent. Until recently, MHI was thought to be fatal and untreatable because mortality rates with conventional medical treatment could exceed 80%. In this unfavourable context, decompressive hemicraniectomy has re-emerged as a therapeutic alternative for selected cases, with reported decreases in mortality ranging between 15% and 40%.

CONCLUSIONS

In recent years, several randomised clinical trials have demonstrated the benefit of decompressive hemicraniectomy in patients with MHI. This treatment reduces mortality in addition to improving functional outcomes.

To establish whether McKenzie lumbar flexion and extension mobility exercises performed in lying affect central as well as systemic hemodynamics: a crossover experimental study

OBJECTIVE

Examine systemic and central hemodynamic responses following McKenzie lumbar flexion and extension mobility exercises performed in lying (FIL and EIL).

DESIGN

Crossover experimental study.

SETTING

Clinical laboratory.

PARTICIPANTS

Healthy male volunteers (n=25) (mean(SD) age: 28(3)years; range 21 to 34).

INTERVENTIONS

Based on alternating assignment of either FIL or EIL to participants, three sets of the first exercise (10, 15, 20 repetitions) were performed with 5-minute rest between sets; after 15-minute rest, the protocol was repeated for the other exercise.

MAIN OUTCOME MEASURES

Systemic hemodynamic parameters included heart rate (HR), and systolic and diastolic blood pressures (SBP, DBP). Central hemodynamic parameters included abdominal aortic diameter (AD), peak systolic velocity (PSV/AD), end diastolic velocity (EDV/AD) and resistive index (RI). Measures recorded after each exercise set.

RESULTS

FIL RPP at baseline was 9.1 (1.4), after 20 repetitions 18.3 (2.5), mean difference 8.9 (95% confidence interval (CI) 7.9 to 9.8) compared to EIL at baseline 9.1 (1.5), after 20 repetitions 13.0 (3.1), mean difference 4.1 (95% CI 3.3 to 5.0). FIL RI at baseline was 0.78 (0.03), after 20 repetitions 0.87 (0.03), mean difference 0.08 (95% CI 0.06 to 0.10) compared to EIL at baseline 0.78 (0.03), after 20 repetitions 0.83 (0.03), mean difference 0.05 (95% CI 0.04 to 0.07).

CONCLUSIONS

Although 10 repetitions of FIL and EIL may be regarded as safe, our findings support screening patients with lifestyle risk factors, and cautioning about adhering to recommended repetition number given associated increased work of the heart. The extent of AD mechanical perturbation remains unclear.

Translati onal challenges of neuroprotection strategy in ischemic stroke

Neuroprotection is a therapeutic strategy that attempts to save neurons from irreversible injury by modifying the effects of the ischemic cascade or facilitating reperfusion. Although numerous agents have shown neuroprotective effect in preclinical trials, their translation to clinical trials failed to show any meaningful effect. The Stroke Therapy Academic Industry Roundtable (STAIR) guidelines were made for performing research on neuroprotective agents in pre-clinical and clinical trials. Although the STAIR guidelines have been available for more than ten years, we still do not have any adequate neuroprotective agents. Reasons for unsuccessful translation from preclinical to clinical research can be considered along stages of drug development: 1) preclinical, 2) transitional and 3) clinical. By extending the therapeutic window for application of intravenous thrombolysis in acute stroke patients to 4.5 hours, as well as increasing the use intra-arterial thrombolysis and development of mechanical devices for thrombectomy in 6 hour period we may be able to achieve some degree of neuroprotection in acute stroke. Future therapy is likely to add to the current thrombolytic therapy with potential neuroprotective drugs or procedures.