Pressure Response Research Articles

The cardiovascular exercise response in children with overweight or obesity measured by cardiovascular magnetic resonance imaging.

Overweight and obesity are among the main causes of cardiovascular diseases. Exercise testing can aid in the early detection of subtle cardiac dysfunction not present in rest. We hypothesized that the cardiovascular response to exercise is impaired among children with overweight or obesity, characterized by the inability of the cardiovascular system to adapt to exercise by increasing cardiac volumes and blood pressure. We performed a cardiovascular stress test to investigate whether the cardiovascular exercise response is altered in children with overweight and obesity, as compared to children with a normal weight. A subgroup of the Generation R population-based prospective cohort study, consisting of 41 children with overweight or obesity and 166 children with a normal weight with a mean age of 16 years, performed an isometric exercise. Continuous heart rate and blood pressure were measured during rest, exercise and recovery. Cardiovascular magnetic resonance (CMR) measurements were performed during rest and exercise. Higher BMI was associated with a higher resting systolic and diastolic blood pressure (difference: 0.24 SDS (95% CI 0.10, 0.37) and 0.20 SDS (95% CI 0.06, 0.33)) and lower systolic and diastolic blood pressure increases from rest to peak exercise (-0.11 SDS (95% CI -0.20, -0.03) and -0.07 SDS (95% CI -0.07, -0.01)). BMI was also associated with a slower decrease in systolic and diastolic blood pressure during recovery (p values < 0.05). Higher childhood BMI was associated with lower BSA corrected left ventricular mass, end-diastolic volume and stroke volume (p values < 0.05). There were no associations of childhood BMI with the cardiac response to exercise measured by heart rate and CMR measurements. Childhood BMI is, across the full range, associated with a blunted blood pressure response to static exercise but there were no differences in cardiac response to exercise. Our findings suggest that adiposity may especially affect the vascular exercise reaction without affecting cardiac response.

Effect of a new resistance training method on the metaboreflex in cardiac rehabilitation patients: a randomized controlled trial.

Patients with cardiac disease exhibit exaggerated sympathoexcitation, pressor, and ventilatory responses to muscle metaboreflex activation (MMA). However, the effects of cardiac rehabilitation (CR) and especially resistance training (RT) modalities on MMA are not well known. This study investigated how CR impacts MMA in such patients, specifically examining the effects of two different resistance training (RT) protocols following 12weeks of CR. In addition to endurance exercises, 32 patients were randomized into either a 3/7 RT modality (comprising 5 sets of 3-7 repetitions) or a control (CTRL) modality (involving 3 sets of 9 repetitions), with distinct inter-set rest intervals (15s for 3/7 and 60s for CTRL). MMA, gauged by blood pressure (BP) and ventilatory (Ve) responses during a handgrip exercise at 40% effort and subsequent post-exercise circulatory occlusion, demonstrated CR's significant impact. Systolic BP, initially at + 28 ± 23% pre-CR, improved to + 11 ± 15% post-CR (P = .011 time effect; P = .131 group effect). Diastolic BP showed a similar trend, from + 27 ± 23% to + 13 ± 15% (P = .099 time effect; P = .087 group effect). Ve, initially at + 60 ± 39%, reduced to + 14 ± 19% post-CR (P < .001 time effect; P = .142 group effect). Critical parameters-maximal oxygen consumption, lean mass, hand grip, and quadriceps strength-exhibited parallel increases in both 3/7 and CTRL groups (P < .05 time effect; P > .3 group effect). Ultimately, CR demonstrated comparable improvements in MMA across both RT modalities, indicating its positive influence on cardiovascular responses and physical performance in individuals with cardiac conditions.

Evaluation of formation mobility inversion methods for formation testing while drilling

Formation mobility is a key parameter for characterizing reservoir permeability and predicting productivity. Formation mobility can be obtained in real-time by formation testing while drilling (FTWD), which is vital for improving the efficiency of oil and gas development and reducing production costs. In terms of FTWD, adopting an appropriate formation mobility inversion method is the key to accurately obtaining the mobility of the formation. The objective of this research is to evaluate the applicability and accuracy of formation mobility inversion methods in various coupled formations. Therefore, the mobility inversion methods for FTWD were reviewed in detail. Then, the process of finite element simulation of FTWD in various coupled formations, including uncoupled, hydro-mechanical coupled, thermal-hydro coupled, and thermal-hydro-mechanical coupled, was introduced. Based on the pressure response of FTWD generated by numerical simulation, four case studies of formation mobility inversion were performed using three different inversion methods, namely pressure drawdown (PDD), area integration (AI), and formation rate analysis (FRA). Finally, an evaluation was performed to assess the applicability of the inversion methods to different coupling formations, and the suggested method for each formation was provided. The results showed that the interpreted formation mobility based on the pressure response of FTWD is the apparent mobility near the wellbore, which can be influenced by the multi-physical coupling effect. The PDD method has a good applicability to high-mobility formations, a general applicability to low-mobility formations, and a poor applicability to tight formations. Both the AI and FRA methods can be used to invert formation mobility under different coupling conditions, and the accuracy of the FRA method is generally superior to that of the AI method. If the formation is in a coupled thermal-hydro-mechanical state, it is recommended to use the AI method, PDD method, and FRA method to invert the mobility for high-mobility, low-mobility, and tight formations, respectively. The results of this paper are beneficial for the accurate interpretation of formation mobility, which can promote the development of oil and gas resources.

Intraocular Pressure Response to Perceived Stress in Juvenile-onset Open-angle Glaucoma.

High perceived stress from academic pressure is associated with intraocular pressure elevation and reduced fluctuation in juvenile-onset open-angle glaucoma patients. Personalized stress assessment and relief strategies may serve as an adjunct therapy in glaucoma. To evaluate the effect of higher perceived stress, resulting from academic pressure, on intraocular pressure (IOP) in juvenile-onset open-angle glaucoma (JOAG) patients compared to healthy individuals. The study included 48 university students aged 18 to 27, comprising 24 JOAG patients on antiglaucoma eyedrops and 24 healthy controls. In an examiner-blind pretest-posttest design, participants' IOP was measured weekly using Goldmann tonometry during three follow-up visits at the beginning and end of the academic semester. Perceived Stress Scale (PSS) scores were also evaluated at these two time points to capture the contrast in perceived stress between periods of low and high academic pressure. Baseline PSS score at the semester's start was lower in both groups (14.1±1.9 in glaucoma vs. 13.5±2.4 in control) and significantly increased by the end of the semester (29.2±2.1 vs. 28.5±1.3; P<0.001), indicating increased perceived stress. Concurrently, IOP rose from 22.01±5.87mmHg to 25.08±5.84mmHg in the glaucoma group and from 11.36±2.03mmHg to 13.65±2.11mmHg in the control group. Factorial analysis revealed a significant interaction between stress and JOAG [F(1,94)=15.94, P=0.001], partial η2=0.08, with stress having a greater increase on IOP in the glaucoma group (+3.10mmHg) compared to the control group (+2.23mmHg) [t(94)=4.457, P<0.001]. Higher perceived stress significantly increases IOP, especially in JOAG patients, suggesting personalised stress management as a potential adjunct therapy for patients.

Respiratory modulation of sympathetic transduction to blood pressure in health and type 2 diabetes.

Type 2 diabetes (T2D) is often accompanied by hypertension, exaggerated blood pressure (BP) responses to sympatho-excitatory stressors, and raised cardiovascular disease risk. Appropriate respiratory-sympathetic coupling and sympathetic transduction to BP are important for short- and longer-term BP control. We tested the hypotheses that respiratory modulation of muscle sympathetic nerve activity (MSNA) and its transduction to BP would be impaired in T2D and associated with higher BP and respiratory-coupled BP variability. Resting MSNA, respiration and beat-to-beat BP were recorded in 20 T2D (49.1 ± 7.4 years; mean ± SD) and 13 healthy control (46.3 ± 9.4 years) participants. MSNA and the transduction of sympathetic bursts (signal-averaging) to mean arterial pressure (MAP) were compared at low and high lung volume phases. The peak MAP response following a sympathetic burst was lower during the high lung volume than low lung volume phase in controls (P = 0.005), whereas it was unchanged with phase in T2D participants (P = 0.522). Respiratory modulation of MSNA was impaired in T2D participants, who had an attenuated reduction in burst incidence from low to the high lung volume phase, versus controls (27.8 ± 38.4% vs. 49.4 ± 24.6%, respectively; P = 0.043). The T2D participants were grouped into unimpaired respiratory modulators (burst incidence modulation median or above) or impaired respiratory modulators (below median). Impaired modulators had higher systolic BP (133 ± 14 vs. 121 ± 11mmHg, P = 0.046), greater Traube-Hering wave amplitudes (6.3 ± 2.4 vs. 4.6 ± 1.1mmHg; P = 0.028) and higher BP variability (MAP average real variability, 2.0 ± 0.7 vs. 1.4 ± 0.3, P = 0.033). Respiratory modulation of MSNA and sympathetic transduction to BP are altered in T2D patients and may contribute to their increased hypertension and cardiovascular risk. KEY POINTS: Respiratory-sympathetic coupling and sympathetic transduction to blood pressure (BP) contribute to short- and longer-term BP control. Our understanding of these processes in health and type 2 diabetes (T2D), a condition with high prevalence of hypertension and cardiovascular risk, is incomplete. We found that respiration and sympathetic transduction to BP are coupled in healthy individuals. The mean arterial pressure response to a sympathetic burst was reduced during the high lung volume compared to the low lung volume phase. This coupling was absent in T2D. Respiratory modulation of muscle sympathetic nerve activity (MSNA) is impaired in T2D, with a blunted reduction of MSNA observed during the high lung volume phase. T2D patients with impaired respiratory MSNA modulation had augmented systolic BP, respiratory-related BP excursions (Traube-Hering waves) and BP variability. Abnormal respiratory modulation of MSNA and sympathetic transduction to BP in T2D may contribute to altered blood pressure control and cardiovascular risk in this population.

The Effect of Angiotensin II Type 1 Receptor Antagonist on Age-Related Differences in Renal Vascular Responses to Angiotensin II in Male and Female Rats.

Advancing age could influence renin angiotensin system components, especially angiotensin type 1 receptor (AT1R). This study examined the effect of AT1R antagonist, losartan, on age-related differences in renal vascular responses to angiotensin II in male and female rats. Forty-eight anesthetized male and female rats (8-12 and 24-28 weeks age ranges) were subjected to catheterize. Then, the responses of mean arterial pressure (MAP), renal perfusion pressure (RPP), renal blood flow (RBF), and renal vascular resistance (RVR) to angiotensin II with or without losartan were determined and evaluated. There were not significant differences in the basal values of MAP, RPP, RBF, and RVR in males. However, it was observed significant difference in RVR in females (P < 0.05). The blockade of AT1R attenuated basal MAP and RPP in all the groups (P < 0.05). The infusion of losartan altered basal RVR and RBF values in female groups (P < 0.05). Moreover, losartan eliminated vasoconstrictor responses to angiotensin II in female groups (P < 0.05). Also, losartan induced significant vascular responses to angiotensin II in male groups (P < 0.05). Losartan could maintain RBF changes in response to angiotensin II in both 8-12- and 24-28-week females. Losartan enhanced the RBF response to angiotensin II in 8-12-week males, but not in 24-28-week males. It seems that females (not males) in various age ranges are resistance against RBF changes by acutely increased angiotensin II.

Which Components of the Haemodynamic Response to Active Stand Predict Cardiovascular Disease and Mortality? Data From The Irish Longitudinal Study on Ageing.

An integrated haemodynamic response during standing may serve as an integrative marker of neuro-cardiovascular function. Individual components of both heart rate (HR) and blood pressure (BP) responses to active stand (AS) have been linked with cardiovascular disease (CVD) and mortality. We assessed longitudinal associations between entire HR/BP response curves during AS, incident CVD and mortality over 12 years. Beat-to-beat measurements of dynamic HR/BP responses to AS were conducted in 4,336 individuals (61.5±8.2 years; 53.7% female). Functional Principal Components Analysis was applied to HR/BP response curves and their association with CVD and mortality assessed. We hypothesised that integrating BP/HR information from the entire haemodynamic response curve may uncover novel associations with both CVD and mortality. Higher systolic BP (SBP) before AS and blunted recovery of SBP during AS was associated with all-cause mortality over 12-years (Hazard Ratio [HR]: 1.14; 1.04, 1.26; p=0.007). Higher baseline/peak HR and lower HR from 30 seconds post stand onwards were associated with lower mortality due to circulatory causes (HR: 0.78; 0.64, 0.95; p = 0.013). Higher HR throughout AS was associated with mortality from other causes (HR: 1.48; 1.22, 1.80; p<0.001). Findings persisted on robust covariate adjustment. We observed distinct relationships between HR/BP responses to AS and 12-year incident CVD and mortality. Integrating the entire haemodynamic response may reveal more nuanced relationships between HR/BP responses to AS, CVD and mortality - serving as an integrative marker of neuro-cardiovascular health in midlife and beyond.

Experimental investigation on the anti-detonation performance of composite structure containing foam geopolymer backfill material

The compression and energy absorption properties of foam geopolymers increase stress wave attenuation under explosion impacts, reducing the vibration effect on the structure. Explosion tests were conducted using several composite structure models, including a concrete lining structure (CLS) without foam geopolymer and six foam geopolymer composite structures (FGCS) with different backfill parameters, to study the dynamic response and wave dissipation mechanisms of FGCS under explosive loading. Pressure, strain, and vibration responses at different locations were synchronously tested. The damage modes and dynamic responses of different models were compared, and how wave elimination and energy absorption efficiencies were affected by foam geopolymer backfill parameters was analyzed. The results showed that the foam geopolymer absorbed and dissipated the impact energy through continuous compressive deformation under high strain rates and dynamic loading, reducing the strain in the liner structure by 52% and increasing the pressure attenuation rate by 28%. Additionally, the foam geopolymer backfill reduced structural vibration and liner deformation, with the FGCS structure showing 35% less displacement and 70% less acceleration compared to the CLS. The FGCS model with thicker, less dense foam geopolymer backfill, having more pores and higher porosity, demonstrated better compression and energy absorption under dynamic impact, increasing stress wave attenuation efficiency. By analyzing the stress wave propagation and the compression characteristics of the porous medium, it was concluded that the stress transfer ratio of FGCS-ρ-579 was 77% lower than that of CLS, and the transmitted wave energy was 90% lower. The results of this study provide a scientific basis for optimizing underground composite structure interlayer parameters.

Innovation as a Buffer: Environmental Institutional Pressure and Organizational Strategic Response

Innovation as a Buffer: Environmental Institutional Pressure and Organizational Strategic Response

Carbon Neutrality Pressure and Strategic Responses

Carbon Neutrality Pressure and Strategic Responses

Intraocular Pressure Response in the Untreated Contralateral Eye After Selective Laser Trabeculoplasty.

To examine the impact of selective laser trabeculoplasty (SLT) on intraocular pressure (IOP) in the untreated contralateral eye within 12 months after the procedure. A retrospective chart review was conducted on patients with primary open-angle, normal-tension, pigmentary, or pseudoexfoliation glaucoma who received 360-degree SLT at George Washington University. Exclusion criteria included prior or subsequent laser or glaucoma surgery within 12 months of SLT, other glaucoma types, or corticosteroid use during follow-up. Primary outcomes were IOP and medication reduction, and SLT success, defined as reducing IOP by ≥20% without additional IOP-lowering procedures or medications. Follow-up occurred at six weeks, six months, and 12 months. Demographic and clinical data were analyzed using ANOVA, paired t-tests, and chi-squared tests. A total of 125 patients were included, representing a range of backgrounds: African American (57.6%), Caucasian (31.2%), Asian (5.6%), and Hispanic/Latino (4%), and 1.6% did not report their background. Significant reductions in mean IOP and medication numbers were observed in the contralateral eye at six weeks and six months (p<0.05) but not at 12 months. The contralateral eye success rates were 24% at six weeks and six months and 20.8% at 12 months. The contralateral eye was more likely to achieve success if the ipsilateral eye was successful at six weeks (odds ratio (95% confidence interval): 5.05 (1.89-13.48)), six months (16.1 (4.56-57.17)), and 12 months (5.94 (2.07-17.04)) (p<0.001 for all). First-time SLT results in statistically significant IOP and medication reductions in the contralateral eye at six weeks and six months. The contralateral eye was 5.05-16.1 times more likely to achieve success if the ipsilateral eye was successful within 12 months.

Adrenal Vein Sampling Results and Surgical Outcomes in Patients with Nonsuppressed Plasma Renin Activity

PurposeTo determine adrenal vein sampling (AVS) and postadrenalectomy outcomes in patients with a nonsuppressed plasma renin activity (PRA) and elevated aldosterone-to-renin ratio (ARR). Materials and MethodsThe study sample included 23 patients with an ARR of >20 and PRA of >1 ng/mL/h (nonsuppressed group) and 69 patients with an ARR of >20 and PRA of <0.6 ng/mL/h (suppressed group) who underwent AVS from 2006 to 2023. Data regarding baseline clinical characteristics, AVS results, and outcomes after adrenalectomy were analyzed. ResultsThe proportion of patients in the nonsuppressed group who had a lateralization index of >4 was lower than that in the suppressed group, although this was nonsignificant (43% vs 62%; P = .15). The mean lateralization index in the nonsuppressed group was lower compared with that in the suppressed group (8.7 vs 17.4; P = .05). The proportion of patients in the nonsuppressed group with improved or cured hypertension following adrenalectomy was similar to that of patients in the suppressed group who also underwent surgery (6/8, 75%, vs 25/32, 78%; P = .71). All hypokalemic patients (32/32) who underwent adrenalectomy had normalization of their potassium levels following procedure. ConclusionsNearly half of patients with nonsuppressed PRA lateralized with AVS. The patients who did lateralize had similar blood pressure response and correction of hypokalemia following adrenalectomy, regardless of PRA. Therefore, patients with a nonsuppressed PRA (>1 ng/mL/h) should still be considered for AVS provided the ARR is elevated.

Multi-fracture growth behavior during TPDF in a horizontal well of multi-clustered perforations: An experimental research

Temporary plugging and diverting fracturing (TPDF), involving inner-fracture temporary plugging (IFTP) and inner-stage temporary plugging (ISTP), has been proposed as a widely applied technique in China, for promoting the uniform initiation and propagation of multi-clustered hydraulic fractures (HFs) in a horizontal well of the shale oil/gas reservoirs. However, how the key plugging parameters controlling the multi-fracture growth and the pumping pressure response during TPDF in shale with dense bedding planes (BPs) and natural fractures (NFs) is still unclear, which limits the optimization of TPDF scheme. In this paper, a series of TPDF simulation experiments within a stage of multi-cluster in a horizontal well were carried out on outcrops of Longmaxi Formation shale using a large-scale true tri-axial fracturing simulation system, combined with the acoustic emission (AE) monitor and computed tomography (CT) scanning techniques. Each experiment was divided into three stages, including the conventional fracturing (CF), IFTP and ISTP. Multi-fracture initiation and propagation behavior, and the dominant controlling parameters were examined, containing the particle sizes, concentration of temporary plugging agent (TPA), and cluster number. The results showed that the number of transverse HFs (THFs) and the overall complexity of fracture morphology increase with the increase in TPA concentration and perforation cluster number. Obviously, the required concentration of TPA is positively correlated with the cluster number. Higher peak values and continuous fluctuations of pumping pressure during TPDF may indicate the creation of diversion fractures. The creation of standard THFs during CF is favorable to the creation of diversion fractures during TPDF. Moreover, the activation of BPs nearby the wellbore during CF is unfavorable to the subsequent pressure buildup during TPDF, resulting in poor plugging and diverting effect. Notably, under the strike-slip fault stress regime, the diversion of THFs is not likely during IFTP, which is similar as the results of ISTP to initiate mainly the un-initiated or under-propagated perforation clusters. Three typical pressure curve types during TPDF can be summarized to briefly identify the hydraulic fracture diversion effects, including good (multiple branches or/and THFs can be newly created), fair (HF initiation along the slightly opened BPs and then activating the NFs), and bad (HF initiation along the largely opened BPs and then connecting with the NFs).

Exploring the Definition and Prognostic Utility of Abnormal Blood Pressure Response During Exercise Stress Testing

Exploring the Definition and Prognostic Utility of Abnormal Blood Pressure Response During Exercise Stress Testing

Self-blame, posttraumatic stress, and cardiovascular reactivity among sexual trauma survivors.

Although trauma is closely linked with hyperarousal and cardiovascular health, little research has examined the effects of posttraumatic stress symptoms (PTSS) on cardiovascular reactivity to trauma reminders among sexual trauma survivors. One type of negative appraisal after trauma, self-blame, is common after sexual trauma, but its relation to cardiovascular reactivity is unknown. The present study aimed to examine the influence of both PTSS and self-blame on blood pressure and heart rate (HR) reactivity to a trauma reminder. Cardiovascular reactivity was measured before, during, and after a laboratory-based sexual trauma reminder among 72 young adult women who have experienced sexual trauma. Higher PTSS predicted lower diastolic blood pressure (DBP) reactivity during the trauma reminder. Higher levels of self-blame predicted higher HR and systolic blood pressure (SBP) reactivity during and after the trauma reminder. Overall, these findings suggest that survivors of sexual trauma with higher levels of PTSS experience a blunting reaction of DBP when exposed to trauma reminders, as opposed to a more typical cardiovascular stress reaction that may elevate and then extinguish to baseline levels. Meanwhile, individuals with higher levels of self-blame have heightened cardiovascular SBP and HR responses during trauma reminders that do not return to baseline levels, perhaps due to self-blame leading individuals to be more 'on guard' to prevent future threats. Longitudinal studies are needed to explore the potential long-term cardiovascular impacts of heightened self-blame and PTSS and their associated cardiovascular reactivity patterns.

UMOD Genotype-Blinded Trial of Ambulatory Blood Pressure Response to Torasemide.

UMOD (uromodulin) has been linked to hypertension through potential activation of Na+-K+-2Cl- cotransporter (NKCC2), a target of loop diuretics. We posited that hypertensive patients carrying the rs13333226-AA UMOD genotype would demonstrate greater blood pressure responses to loop diuretics, potentially mediated by this UMOD/NKCC2 interaction. This prospective, multicenter, genotype-blinded trial evaluated torasemide (torsemide) efficacy on systolic blood pressure (SBP) reduction over 16 weeks in nondiabetic, hypertensive participants uncontrolled on ≥1 nondiuretic antihypertensive for >3 months. The primary end point was the change in 24-hour ambulatory SBP (ABPM SBP) and SBP response trajectories between baseline and 16 weeks by genotype (AA versus AG/GG) due to nonrandomized groups at baseline (ClinicalTrials.gov: NCT03354897). Of 251 enrolled participants, 222 received torasemide and 174 demonstrated satisfactory treatment adherence and had genotype data. The study participants were middle-aged (59±11 years), predominantly male (62%), obese (body mass index, 32±7 kg/m2), with normal eGFR (92±17 mL/min/1.73 m²) and an average baseline ABPM of 138/81 mm Hg. Significant reductions in mean ABPM SBP were observed in both groups after 16 weeks (AA, -6.57 mm Hg [95% CI, -8.44 to -4.69]; P<0.0001; AG/GG, -3.22 [95% CI, -5.93 to -0.51]; P=0.021). The change in mean ABPM SBP (baseline to 16 weeks) showed a difference of -3.35 mm Hg ([95% CI, -6.64 to -0.05]; P=0.048) AA versus AG/GG genotypes. The AG/GG group displayed a rebound in SBP from 8 weeks, differing from the consistent decrease in the AA group (P=0.004 for difference in trajectories). Our results confirm a plausible interaction between UMOD and NKCC2 and suggest a potential role for genotype-guided use of loop diuretics in hypertension management. URL: https://www.clinicaltrials.gov; Unique identifier: NCT03354897.

Design of AI-Enhanced and Hardware-Supported Multimodal E-Skin for Environmental Object Recognition and Wireless Toxic Gas Alarm

HighlightsA novel organohydrogel-based multimodal e-skin with excellent sensing performance for temperature, humidity, pressure, proximity, and NO2 is proposed for the first time, showing powerful sensing capabilities beyond natural skin.The developed multimodal e-skin exhibited extraordinary sensing performance at room temperature, including fast pressure response time (0.2 s), high temperature sensitivity (9.38% °C-1), a wide range of humidity response (22%–98% RH), high NO2 sensitivity (254% ppm-1), a low detection limit (11.1 ppb NO2) and the abilities to sense the proximity of objects accurately, which are yet achieved by previous e-skins.The multimodal e-skin was combined with the deep neural network algorithm and wireless alarm circuit to achieve zero-error classification of different objects and rapid response to NOx leak incidents, proving the feasibility of the e-skin-assisted rescue robot for post-earthquake rescue.

Critical thresholds of long-pressure reactivity index and impact of intracranial pressure monitoring methods in traumatic brain injury

BackgroundModerate-to-severe traumatic brain injury (TBI) has a global mortality rate of about 30%, resulting in acquired life-long disabilities in many survivors. To potentially improve outcomes in this TBI population, the management of secondary injuries, particularly the failure of cerebrovascular reactivity (assessed via the pressure reactivity index; PRx, a correlation between intracranial pressure (ICP) and mean arterial blood pressure (MAP)), has gained interest in the field. However, derivation of PRx requires high-resolution data and expensive technological solutions, as calculations use a short time-window, which has resulted in it being used in only a handful of centers worldwide. As a solution to this, low resolution (longer time-windows) PRx has been suggested, known as Long-PRx or LPRx. Though LPRx has been proposed little is known about the best methodology to derive this measure, with different thresholds and time-windows proposed. Furthermore, the impact of ICP monitoring on cerebrovascular reactivity measures is poorly understood. Hence, this observational study establishes critical thresholds of LPRx associated with long-term functional outcome, comparing different time-windows for calculating LPRx as well as evaluating LPRx determined through external ventricular drains (EVD) vs intraparenchymal pressure device (IPD) ICP monitoring.MethodsThe study included a total of n = 435 TBI patients from the Karolinska University Hospital. Patients were dichotomized into alive vs. dead and favorable vs. unfavorable outcomes based on 1-year Glasgow Outcome Scale (GOS). Pearson’s chi-square values were computed for incrementally increasing LPRx or ICP thresholds against outcome. The thresholds that generated the greatest chi-squared value for each LPRx or ICP parameter had the highest outcome discriminatory capacity. This methodology was also completed for the segmentation of the population based on EVD, IPD, and time of data recorded in hospital stay.ResultsLPRx calculated with 10–120-min windows behaved similarly, with maximal chi-square values ranging at around a LPRx of 0.25–0.35, for both survival and favorable outcome. When investigating the temporal relations of LPRx derived thresholds, the first 4 days appeared to be the most associated with outcomes. The segmentation of the data based on intracranial monitoring found limited differences between EVD and IPD, with similar LPRx values around 0.3.ConclusionOur work suggests that the underlying prognostic factors causing impairment in cerebrovascular reactivity can, to some degree, be detected using lower resolution PRx metrics (similar found thresholding values) with LPRx found clinically using as low as 10 min-by-minute samples of MAP and ICP. Furthermore, EVD derived LPRx with intermittent cerebrospinal fluid draining, seems to present similar outcome capacity as IPD. This low-resolution low sample LPRx method appears to be an adequate substitute for the clinical prognostic value of PRx and may be implemented independent of ICP monitoring method when PRx is not feasible, though further research is warranted.

Comparison of isometric handgrip test among pregnant offspring of hypertensive parents and pregnant offspring of non-hypertensive parents.

A family history of hypertension is one of the important risk factors for the development of pregnancy-induced hypertension (PIH). Offspring of hypertensive parents should be screened for PIH. The isometric handgrip (IHG) test is used to assess autonomic function among them. Autonomic function dysregulation can indicate their predisposition to develop PIH later in the course of pregnancy. To compare the IHG among pregnant offspring of hypertensive parents (Group 1) and non-hypertensive parents (Group 2). This is a cross-sectional study done among 100 pregnant women in the second trimester (50 participants in each group). Blood pressure responses to sustained hand grip for 2 minutes of maximum voluntary contraction (MVC) were recorded, immediately at the end of the IHG test and after 5 minutes of the IHG test. Independent t-test and Mann-Whitney U test were used to compare the responses in two groups. There is no statistical difference in basal blood pressure and heart rate between the two groups. Group 1 exhibited a significant increase in systolic blood pressure (SBP) and diastolic blood pressure (DBP) compared to Group 2 immediately after 2 minutes of the IHG test. There is a significant increase in SBP after 5 minutes of the IHG in Group 2. Offspring of hypertensive parents have increased sympathetic reactivity and restoration of the blood pressure is significantly less compared to offspring of normotensive parents, which may predispose them for PIH. IHG can be applied as a convenient tool to screen the population who are at risk of PIH in places like primary health centres or field screenings where IHG is one possible option.

Blood pressure response index and clinical outcomes in patients with septic shock: a multicenter cohort study

Sepsis is a leading cause of mortality in intensive care units and vasoactive drugs are widely used in septic patients. The cardiovascular response of septic shock patients during resuscitation therapies and the relationship of the cardiovascular response and clinical outcome has not been clearly described. We included adult patients admitted to the ICU with sepsis from Peking Union Medical College Hospital (internal), Medical Information Mart for Intensive Care IV (MIMIC-IV) and eICU Collaborative Research Database (eICU-CRD). The Blood Pressure Response Index (BPRI) was defined as the ratio between the mean arterial pressure and the vasoactive-inotropic score. BRRI was compared with existing risk scores on predicting in-hospital death. The relationship between BPRI and in-hospital mortality was calculated. A XGBoost's machine learning model identified the features that influence short-term changes in BPRI. There were 2139, 9455, and 4202 patients in the internal, MIMIC-IV and eICU-CRD cohorts, respectively. BPRI had a better AUROC for predicting in-hospital mortality than SOFA (0.78 vs. 0.73, p=0.01) and APS (0.78 vs. 0.74, p=0.03) in the internal cohort. The estimated odds ratio for death per unit decrease in BPRI was 1.32 (95% CI 1.20-1.45) when BPRI was below 7.1 vs. 0.99 (95% CI 0.97-1.01) when BPRI was above 7.1 in the internal cohort; similar relationships were found in MIMIC-IV and eICU-CRD. Respiratory support and latest cumulative 12-h fluid balance were intervention-related features influencing BPRI. BPRI is an easy, rapid, precise indicator of the response of patients with septic shock to vasoactive drugs. It is a comparable and even better predictor of prognosis than SOFA and APS in sepsis and it is simpler and more convenient in use. The application of BPRI could help clinicians identify potentially at-risk patients and provide clues for treatment. Fundings for the Beijing Municipal Natural Science Foundation; the National High Level Hospital Clinical Research Funding; the CAMS Innovation Fund for Medical Sciences (CIFMS) from Chinese Academy of Medical Sciences and the National Key R&D Program of China, Ministry of Science and Technology of the People's Republic of China.