Evaluation and application of ultra-low-frequency pressure reactivity index in pediatric traumatic brain injury patients.

PURPOSE: While clinical practice suggests that knowing the cerebral autoregulation (CA) status of traumatic brain injury (TBI) patients is crucial in assessing the best treatment, evidence in pediatric TBI (pTBI) is limited. The pressure reactivity index (PRx) is a surrogate method for the continuous estimation of CA in adults; however, calculations require continuous, high-resolution monitoring data. We evaluate an ultra-low-frequency pressure reactivity index (UL-PRx), based on data sampled at ∼5-min periods, and test its association with 6-month mortality and unfavorable outcome in a cohort of pTBI patients. METHODS: Data derived from pTBI patients (0-18 years) requiring intracranial pressure (ICP) monitoring were retrospectively collected and processed in MATLAB using an in-house algorithm. RESULTS: Data on 47 pTBI patients were included. UL-PRx mean values, ICP, cerebral perfusion pressure (CPP), and derived indices showed significant association with 6-month mortality and unfavorable outcome. A value of UL-PRx of 0.30 was identified as the threshold to better discriminate both surviving vs deceased patients (AUC: 0.90), and favorable vs unfavorable outcomes (AUC: 0.70) at 6 months. At multivariate analysis, mean UL-PRx and % time with ICP > 20 mmHg, remained significantly associated with 6-month mortality and unfavorable outcome, even when adjusted for International Mission for Prognosis and Analysis of Clinical Trials in TBI (IMPACT)-Core variables. In six patients undergoing secondary decompressive craniectomy, no significant changes in UL-PRx were found after surgery. CONCLUSIONS: UL-PRx is associated with a 6-month outcome even if adjusted for IMPACT-Core. Its application in pediatric intensive care unit could be useful to evaluate CA and offer possible prognostic and therapeutic implications in pTBI patients. CLINICALTRIALS: GOV: NCT05043545, September 14, 2021, retrospectively registered.

Covid-19 and gender: lower rate but same mortality of severe disease in women-an observational study.

BACKGROUND: Gender-related factors might affect vulnerability to Covid-19. The aim of this study was to describe the role of gender on clinical features and 28-day mortality in Covid-19 patients. METHODS: Observational study of Covid-19 patients hospitalized in Bergamo, Italy, during the first three weeks of the outbreak. Medical records, clinical, radiological and laboratory findings upon admission and treatment have been collected. Primary outcome was 28-day mortality since hospitalization. RESULTS: 431 consecutive adult patients were admitted. Female patients were 119 (27.6%) with a mean age of 67.0 ± 14.5 years (vs 67.8 ± 12.5 for males, p = 0.54). Previous history of myocardial infarction, vasculopathy and former smoking habits were more common for males. At the time of admission PaO2/FiO2 was similar between men and women (228 [IQR, 134-273] vs 238 mmHg [150-281], p = 0.28). Continuous Positive Airway Pressure (CPAP) assistance was needed in the first 24 h more frequently in male patients (25.7% vs 13.0%; p = 0.006). Overall 28-day mortality was 26.1% in women and 38.1% in men (p = 0.018). Gender did not result an independent predictor of death once the parameters related to disease severity at presentation were included in the multivariable analysis (p = 0.898). Accordingly, the Kaplan-Meier survival analysis in female and male patients requiring CPAP or non-invasive ventilation in the first 24 h did not find a significant difference (p = 0.687). CONCLUSION: Hospitalized women are less likely to die from Covid-19; however, once severe disease occurs, the risk of dying is similar to men. Further studies are needed to better investigate the role of gender in clinical course and outcome of Covid-19.

Autonomic Abnormalities in Patients With Primary Sjogren's Syndrome - Preliminary Results.

Primary Sjögren's syndrome (pSS) is an autoimmune disease affecting exocrine glands and extra-glandular organs. There are conflicting reports on the presence of autonomic dysfunction in pSS and no data are available on the functional status of sympathetic outflow to the vessels and baroreceptor [baroreflex sensitivity (BRS)] control mechanisms. We investigated the cardiac (cBRS) and sympathetic (sBRS) baroreceptor modulation in both time and frequency domains and the cardiovascular autonomic profile in pSS patients compared to healthy controls. Autonomic symptoms were quantified by the Composite Autonomic Symptom Scale (COMPASS31) three-item questionnaire. The EULAR Sjogren's syndrome patient reported index (ESSPRI) questionnaire evaluated the magnitude of pSS clinical symptoms, i.e., fatigue, pain, and sicca symptoms. Electrocardiogram, beat-by-beat arterial pressure (AP) and respiratory activity were continuously recorded in 17 pSS patients and 16 healthy controls, while supine and during 75° head-up tilt. In seven patients and seven controls, muscle sympathetic nerve activity (MSNA) was measured. Spectrum analysis of RR variability provided markers of cardiac vagal modulation (HFRR nu) and sympatho-vagal balance [low frequency (LF)/high frequency (HF)]. The power of LF (0.1 Hz) oscillations of systolic arterial pressure (SAP) variability (LFSAP) evaluated the vasomotor response to sympathetic stimulation. Compared to controls, pSS patients scored higher in total COMPASS31 (p < 0.0001) and all ESSPRI subdomains (fatigue, p = 0.005; pain, p = 0.0057; dryness, p < 0.0001). Abnormal scialometry (<1.5 ml/15 min) and Schirmer tests (<5 mm/5 min) were found in pSS patients and salivary flow rate was negatively associated with ESSPRI dryness (p = 0.0014). While supine, pSS patients had lower SEQcBRS index of cardiac baroreceptor sensitivity, higher HFRRnu (p = 0.021), lower LF/HF (p = 0.007), and greater MSNA (p = 0.038) than controls. No differences were observed in LFSAP between groups. During orthostatic challenge, although LFSAP increased similarly in both groups, MSNA was greater in pSS patients (p = 0.003). At rest pSS patients showed lower cBR control and greater parasympathetic modulation. Furthermore, greater sympathetic nerve activity was observed in pSS patients while supine and in response to gravitational challenge. We hypothesized that such enhanced sympathetic vasoconstrictor activity might reflect an attempt to maintain blood pressure in a setting of likely reduced vascular responsiveness.

Modeling the Perception of Audiovisual Distance: Bayesian Causal Inference and Other Models.

Studies of audiovisual perception of distance are rare. Here, visual and auditory cue interactions in distance are tested against several multisensory models, including a modified causal inference model. In this causal inference model predictions of estimate distributions are included. In our study, the audiovisual perception of distance was overall better explained by Bayesian causal inference than by other traditional models, such as sensory dominance and mandatory integration, and no interaction. Causal inference resolved with probability matching yielded the best fit to the data. Finally, we propose that sensory weights can also be estimated from causal inference. The analysis of the sensory weights allows us to obtain windows within which there is an interaction between the audiovisual stimuli. We find that the visual stimulus always contributes by more than 80% to the perception of visual distance. The visual stimulus also contributes by more than 50% to the perception of auditory distance, but only within a mobile window of interaction, which ranges from 1 to 4 m.