Preserved Electroencephalogram Power and Global Synchronization Predict Better Neurological Outcome in Sudden Cardiac Arrest Survivors.

Quantitative EEG (qEEG) delineates complex brain activities. Global field synchronization (GFS) is one multichannel EEG analysis that measures global functional connectivity through quantification of synchronization between signals. We hypothesized that preservation of global functional connectivity of brain activity might be a surrogate marker for good outcome in sudden cardiac arrest (SCA) survivors. In addition, we examined the relation of phase coherence and GFS in a mathematical approach. We retrospectively collected EEG data of SCA survivors in one academic medical center. We included 75 comatose patients who were resuscitated following in-hospital or out-of-hospital nontraumatic cardiac arrest between 2013 and 2017 in the intensive care unit (ICU) of National Taiwan University Hospital (NTUH). Twelve patients (16%) were defined as good outcome (GO) (CPC 1-2). The mean age in the GO group was low (51.6 ± 15.7 vs. 68.1 ± 12.9, p < 0.001). We analyzed standard EEG power, computed EEG GFS, and assessed the cerebral performance category (CPC) score 3 months after discharge. The alpha band showed the highest discrimination ability (area under curve [AUC] = 0.78) to predict GO using power. The alpha band of GFS showed the highest AUC value (0.8) to predict GO in GFS. Furthermore, by combining EEG power + GFS, the alpha band showed the best prediction value (AUC 0.86) in predicting GO. The sensitivity of EEG power + GFS was 73%, specificity was 93%, PPV was 0.67%, and NPV was 0.94%. In conclusion, by combining GFS and EEG power analysis, the neurological outcome of the nontraumatic cardiac arrest survivor can be well-predicted. Furthermore, we proved from a mathematical point of view that although both amplitude and phase contribute to obtaining GFS, the interference in phase variation drastically changes the possibility of generating a good GFS score.

Probing penile hemodynamics by using photoplethysmography as objective indicators for male erection quality and sexual function.

Erectile dysfunction (ED) is mostly due to the lack of blood flow into the penis. In the past 20 years, near-infrared spectroscopy (NIRS) was used in measuring the concentrations and temporal dynamics of different hemoglobin types. However, the dynamics of the light absorption (photoplethysmography; PPG) have not been applied to survey penile hemodynamics and erection quality. This paper compared the use of photoplethysmography (PPG) to study vascular ED with standard penile Doppler ultrasonography. Men diagnosed with vascular ED for at least 6 months and nominated for penile ultrasonography were included. PPG signals were collected during the ultrasound examination. All beat-to-beat PPG waveforms were aligned with the peak and averaged to one representative template waveform for feature analysis, including amplitude differences (APD) index, reflection time index (RTI), augmentation index (AI), and perfusion index (PI). An inverse correlation was found between end-erection amplitude and both erection hardness score (EHS) and resistive index (RI). APD index and EHS as well as the international index of erectile function-5 (IIEF) and RI were positively correlated. RTI and AI were inversely correlated to IIEF and RI. PI was positively correlated to RI. PPG may therefore be useful as a noninvasive, convenient, technique for sexual function evaluation.

Noninvasive Hemodynamic Profiles during Hemodialysis in Patients with and without Heart Failure.

BACKGROUND: Although the dynamics of blood pressure (BP) during dialysis provide information related to the control system, the prognosis and relationships between temporal changes in intradialytic hemodynamic regulation, BP, and decreased cardiac function remain largely unclear. METHODS: Hemodynamic parameters, including heart rate (HR), stroke volume (SV), cardiac index, and systemic vascular resistance index, were recorded using a noninvasive hemodynamic device on a beat-by-beat basis in 40 patients on dialysis who were divided into three groups, i.e., those with and without BP lability and those with heart failure (HF). Statistical measurements, including mean, standard deviation, coefficient of variation (CV), and index of nonrandomness of each hemodynamic parameter were derived from the three different phases divided equally during dialysis and compared using 3×3 two-way mixed-model analysis of variance to determine the effects of the different stages of hemodialysis (HD), cardiac function, and intradialytic changes in BP on the hemodynamic parameters. In addition, multivariate Cox regression was performed to determine the association between the changes in the derived parameters and BP lability. RESULTS: The average SV tended to decrease during HD in all groups (p = 0.041). A significant decrease was observed in the CV of SV between the first two stages of HD in patients with labile BP and HF when compared to those without labile BP (p = 0.037). Significant interactions between group and stage of the index of nonrandomness for HR were also noted; this index was significantly higher in patients without labile BP than in those with labile BP or HF (p = 0.048). A higher difference between the early and middle stages of HD for nonrandomness indexes of HR was an independent predictor of reduced BP lability during HD (HR = 0.844, 95% confidence interval 0.722-0.987, p = 0.034). CONCLUSIONS: Increases in the CV of SV and the index of nonrandomness for HR during early-stage HD in response to decreased SV may be associated with better BP control during HD. This finding suggests that patients with more structurally meaningful hemodynamic control have a more favorable cardiovascular outcome.