Higher Mean Arterial Pressure Research Articles

The effect of baroreflex-induced sympathetic suppression on renal arterial impedance in rats

Objective: We examined the effect of baroreflex on renal arterial impedance (ZRA) to gain insights into renal hemodynamics and local autoregulation. Methods: This study involved male Wistar-Kyoto rats (n = 6). We measured renal arterial pressure (PRA) and renal arterial flow (FRA). For high-resolution renal arterial impedance (ZRA) over the frequency range of 0.1-70 Hz, random pacing was employed. We isolated the bilateral carotid sinus baroreceptor regions and utilized a servo pump to control carotid sinus pressure (CSP) either at 60 mmHg or 140 mmHg. We controlled mean arterial pressure (AP) at 100 mmHg (AP-fix) or allowed to vary in response to changes in CSP (AP-variable). A three‐element Windkessel (3-WK) model was used to quantify ZRA (R1: proximal resistance, R2: distal resistance, and C: renal compliance). Results: With AP-fix, an increase of CSP from 60 mmHg to 140 mmHg did not change mean PRA (99.85 ± 0.16 vs. 98.00 ± 1.22 mmHg, P = ns) or mean FRA (8.73 ± 0.41 vs. 8.10 ± 0.38 min/mL, Δ = −7%, P = ns). This rise of CSP did not significantly affect R1 (0.74 ± 0.11 vs. 0.61 ± 0.12 mmHg·min/mL, P = ns) or R2 (8.13 ± 1.08 vs. 8.79 ± 0.85 mmHg·min/mL, P = ns), but it did increase C by 20% (4.05 ± 0.47 vs. 4.88 ± 0.35 (×10−5) mL/mmHg, P < 0.05). With AP-variable, elevating CSP from 60 mmHg to 140 mmHg significantly lowered mean PRA by 38% (105.42 ± 2.84 vs. 65.15 ± 4.87 mmHg, P < 0.01), but did not change mean FRA (9.00 ± 0.48 vs. 7.92 ± 0.66 min/mL, Δ = −12%, P = ns). Changes in CSP did not affect R1 (0.77 ± 0.12 vs. 1.23 ± 0.24 mmHg·min/mL, P = ns), but they did reduce R2 by 41% (8.01 ± 1.08 vs. 4.76 ± 0.79 mmHg·min/mL, P < 0.01) and increase C almost five-fold (3.79 ± 0.36 vs. 22.16 ± 6.91 (×10−5) mL/mmHg, P < 0.05). Conclusion: The minor change in FRA (−12%) despite a 38% drop in PRA suggests the presence of local autoregulation to buffer changes in renal blood flow. The primary effect of renal hemodynamic regulation on ZRA was found in R2. When AP was allowed to vary in response to changes in CSP, increasing CSP, the baroreflex-induced sympathetic suppression decreased R2. However, when AP was held constant at 100 mmHg, the reduction in R2 was not observed, even with baroreflex activation resulting from changes in CSP. Hence, the local renal autoregulation may counteract the baroreflex, maintaining renal blood flow unchanged. Such a mechanism serves to protect the glomeruli from exogenously induced high mean AP. NTT Research, Inc. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Preperitoneal pelvic balloon tamponade-an effective intervention to control pelvic injury hemorrhage in a swine model.

Objective: This study aimed to estimate the effects of the volume of preperitoneal balloon (PPB) on arterial and venous hemorrhage in a swine pelvic fracture model. Methods: Twenty-four swine were randomized into 0-mL, 500-mL, 800-mL, and 1000-mL intra-hematoma PPB groups. They were subjected to open-book pelvic fracture and reproducible injuries in the external iliac artery and vein. The pelvic binder and IH-PPBs with different volumes of fluid were applied to control the active hemorrhage after arterial and venous injuries. The survival time and rate during 60-min observation and digital subtraction angiography (DSA) images were the primary endpoints in this study. Secondary endpoints included survival rate within 70min, peritoneal pressure, hemodynamics, blood loss, infusion fluid, blood pH, and lactate concentration. Results: Our results indicated that the 800-mL and 1000-mL groups had a higher survival rate (0%, 50%, 100% and 100% for 0, 500, 800, and 1000-mL groups respectively; p < 0.0001) and longer survival time (13.83 ± 2.64, 24.50 ± 6.29, 55.00 ± 6.33, and 60.00 ± 0.00min for 0, 500, 800, and 1,000 groups respectively; p < 0.0005) than the 0-mL or 500-mL groups during the 60min observation. Contrastingly, survival rate and time were comparable between 800-mL and 1000-mL groups during the 60-min observation. The IH-PPB volume was associated with an increase in the pressure of the balloon and the preperitoneal pressure but had no effect on the bladder pressure. Lastly, the 1000-mL group had a higher mean arterial pressure and systemic vascular resistance than the 800-mL group. Conclusion: IH-PPB volume-dependently controls vascular bleeding after pelvic fracture in the swine model. IH-PPB with a volume of 800mL and 1000mL efficiently managed pelvic fracture-associated arterial and venous hemorrhage and enhanced survival time and rate in the swine model without evidences of visceral injury.

CENTRAL VENOUS-TO-ARTERIAL CARBON DIOXIDE PARTIAL PRESSURE DIFFERENCE AS A GUIDING PARAMETER FOR CARDIOTONIC DRUG ADMINISTRATION IN PATIENTS WITH EARLY-STAGE SEPTIC SHOCK.

Objective: This study aimed to investigate the effect of the central venous-to-arterial carbon dioxide partial pressure difference (Pcv-aCO2) on the administration of cardiotonic drugs in patients with early-stage septic shock. Methods: A retrospective study was conducted on 120 patients suffering from septic shock. At admission, the left ventricular ejection fraction (LVEF) and Pcv-aCO2 of the patients were obtained. On the premise of mean arterial pressure ≥ 65 mm Hg, the patients were divided into two groups according to the treatment approaches adopted by different doctors-control group: LVEF ≤50% and observation group: Pcv-aCO2 ≥ 6. Both groups received cardiotonic therapy. Results: The two groups of patients had similar general conditions and preresuscitation conditions ( P > 0.05). Compared with the control group, the observation group had a higher mean arterial pressure, lactic acid clearance rate, and urine output after 6 h of resuscitation ( P < 0.05), but a lower absolute value of lactic acid, total fluid intake in 24 h, and a lower number of patients receiving renal replacement therapy during hospitalization ( P < 0.05). After 6 hours of resuscitation, the percentages of patients meeting central venous oxygen saturation and central venous pressure targets were not significantly different between the control and observation groups ( P > 0.05). There was no difference in the 28-day mortality rate between the two groups ( P > 0.05). Conclusion: Pcv-aCO2 is more effective than LVEF in guiding the administration of cardiotonic drugs in the treatment of patients with septic shock.

Capillary refill time response to a fluid challenge or a vasopressor test: an observational, proof-of-concept study

BackgroundSeveral studies have validated capillary refill time (CRT) as a marker of tissue hypoperfusion, and recent guidelines recommend CRT monitoring during septic shock resuscitation. Therefore, it is relevant to further explore its kinetics of response to short-term hemodynamic interventions with fluids or vasopressors. A couple of previous studies explored the impact of a fluid bolus on CRT, but little is known about the impact of norepinephrine on CRT when aiming at a higher mean arterial pressure (MAP) target in septic shock. We designed this observational study to further evaluate the effect of a fluid challenge (FC) and a vasopressor test (VPT) on CRT in septic shock patients with abnormal CRT after initial resuscitation. Our purpose was to determine the effects of a FC in fluid-responsive patients, and of a VPT aimed at a higher MAP target in chronically hypertensive fluid-unresponsive patients on the direction and magnitude of CRT response.MethodsThirty-four septic shock patients were included. Fluid responsiveness was assessed at baseline, and a FC (500 ml/30 mins) was administered in 9 fluid-responsive patients. A VPT was performed in 25 patients by increasing norepinephrine dose to reach a MAP to 80–85 mmHg for 30 min. Patients shared a multimodal perfusion and hemodynamic monitoring protocol with assessments at at least two time-points (baseline, and at the end of interventions).ResultsCRT decreased significantly with both tests (from 5 [3.5–7.6] to 4 [2.4–5.1] sec, p = 0.008 after the FC; and from 4.0 [3.3–5.6] to 3 [2.6 -5] sec, p = 0.03 after the VPT. A CRT-response was observed in 7/9 patients after the FC, and in 14/25 pts after the VPT, but CRT deteriorated in 4 patients on this latter group, all of them receiving a concomitant low-dose vasopressin.ConclusionsOur findings support that fluid boluses may improve CRT or produce neutral effects in fluid-responsive septic shock patients with persistent hypoperfusion. Conversely, raising NE doses to target a higher MAP in previously hypertensive patients elicits a more heterogeneous response, improving CRT in the majority, but deteriorating skin perfusion in some patients, a fact that deserves further research.

Cortical Laminar Necrosis After Severe Hydrocephalus: Case Report and Review of the Literature

Objectives We present a case of cortical laminar necrosis after severe hydrocephalus to highlight considerations for multimodal cerebral autoregulation monitoring to determine mean arterial pressure (MAP) thresholds during neurological emergencies, as well as postoperative head imaging for patients with ventriculoperitoneal shunts (VPS). Methods A 40-year-old woman with a history of Chiari II malformation and non-communicating hydrocephalus with VPS presented in septic shock from a sacral wound. One week after colostomy for fecal diversion, the patient became comatose and had progressive slowing to full suppression on electroencephalogram (EEG). Results CT imaging revealed hydrocephalus, most likely due to VPS distal obstruction from intraperitoneal surgery. Despite neurosurgical and neurocritical care management, MRI confirmed diffuse cortical hypoxic ischemic injury. Discussion The Neurocritical Care Society’s Emergency Neurological Life Support (ENLS) protocol for neurological emergencies focuses on managing increased intracranial pressure (ICP) but does not set MAP goals. As ICP may be very high during brain herniation, our case demonstrates that higher MAP may be required to maintain adequate circulation. To determine the optimal MAP target, bedside multimodality monitoring, including ICP monitors, transcranial doppler, and near infrared spectroscopy, can help establish individualized cerebral autoregulation guided thresholds. Outside of a neurological intensive care unit, EEG can monitor cerebral blood flow and indicate windows for intervention before exam or imaging changes. Additionally, our case demonstrates how a post-operative surveillance CT head should be considered for patients with VPS.

The association between mean arterial pressure and acute kidney injury reversal among patients with decompensated cirrhosis.

This study informs how mean arterial pressure (MAP) impacts acute kidney injury (AKI) recovery among all patients hospitalized with cirrhosis, regardless of etiology. We identified incident AKI episodes among subjects in our cohort of patients with decompensated cirrhosis. AKI was defined as a ≥50% increase in creatinine from an outpatient baseline (≥7 days prior) that required hospitalization. Linear mixed effects models were completed to determine the impact between AKI recovery, MAP, and time. To determine the impact of MAP on AKI reversal, we completed time-dependent Cox regression models with time beginning at the time of peak creatinine and ending at death, discharge, or AKI reversal, among those hospitalized with AKI and those with persistent AKI (≥48h) We identified 702 hospitalized patients with cirrhosis with AKI. We found those with AKI reversal had, on average, higher MAP (2.1mmHg, p <0.05) and a greater increase in MAP over time (0.1mmHg per hour, p <0.001). Among all 702 hospitalized patients with AKI and adjusted for confounders, each 5mmHg increase in MAP was associated with 1.07× the hazard of AKI reversal ( p <0.01). Similarly, among those with persistent AKI after adjusting for confounders, each 5mmHg increase in MAP was associated with a 1.19× greater likelihood of AKI reversal ( p <0.001). Our data demonstrate that MAP significantly increases the likelihood of AKI recovery regardless of severity or injury or AKI phenotype. We believe these data highlight the importance of MAP as a clinical tool to promote kidney function recovery among patients with cirrhosis hospitalized with AKI.

Prospective Randomized Pilot Trial on the Effects of Mild Hypercapnia on Cerebral Oxygen Saturation in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting

A single-center prospective randomized controlled study was conducted to assess the effect of targeted mild hypercapnia (TMH) on cerebral oxygen saturation (rSO2) in patients undergoing off-pump coronary artery bypass grafting (CABG). A prospective randomized controlled study involving 100 patients undergoing off-pump CABG at U. N. Mehta Hospital, Ahmedabad, Gujarat, India. Patients were randomized to either the TMH (PaCO2 45-55 mmHg) or the targeted normocapnia (TN; PaCO2 35-45 mmHg) group, containing 50 patients in each group. Monitoring of rSO2, heart rate, mean arterial pressure (MAP), PaCO2, and peripheral oxygen saturation was done at baseline, after induction, after left internal mammary artery harvesting, at each grafting (distal and proximal), after protamine, and after shifting to the intensive care unit. The standardized minimental-state examination (SMMSE) was performed preoperatively and at 8, 12, and 24 hours postextubation. Data were analyzed using an independent sample t test. The TMH group had higher MAP during grafting (p < 0.001) and higher rSO2 on both sides during distal and proximal grafting (p < 0.001) and after protamine (p < 0.05), as compared to the TN group. Compared to preoperative values, SMMSE scores in the TN group were significantly lower at 12 and 24 hours postextubation (p < 0.001). TMH during grafting increased the cerebral blood flow and rSO2 when hemodynamic instability was very common. It has a protective role on the brain and helps maintain cognition postoperatively.

Maternal cardiovascular function at mid-gestation is related to placental angiogenesis.

To investigate whether placental function, reflected in the levels of angiogenic factors, is associated with maternal cardiac function and hemodynamic responses at 19 to 24 weeks' gestation after adjustment for maternal risk factors and pregnancy complications. Prospective study on women with singleton pregnancies attending Kings' College Hospital, London, UK for a routine hospital visit at 19-24 weeks' gestation. We recorded maternal characteristics and measured mean arterial pressure, maternal heart rate, serum placental growth factor and soluble fms-like tyrosine kinase 1 (sFLT-1).We also performed maternal echocardiogram to assess cardiac output and peripheral vascular resistance as well as indices of diastolic and systolic function. Our cohort included 4006 women.Lower placental growth factor (PlGF) values were significantly associated with higher mean arterial pressure (MAP) (p<0.001), lower maternal heart rate (p<0.001), lower mitral valve s' velocity (p= 0.027) and higher left atrial volume (p=0.022) after adjustment for maternal characteristics and pregnancy complications. sFLT-1 was positively related to relative wall thickness (p= 0.012), whereas sFLT-1/ PlGF ratio was negatively associated with mitral valve A (p= 0.006) and positively associated with left atrial volume (p= 0.015) and MAP (p= 0.004). The magnitude of these associations was similar in the subgroup of women without any risk factors from their obstetric and medical history. A continuous link of moderate strength between angiogenic factors and subclinical maternal cardiac function alterations is present at mid-gestation, independently of preexisting maternal risk factors and pregnancy complications. Impaired placental function appears to be related to a mild systolic and diastolic dysfunction and cardiac remodeling. This article is protected by copyright. All rights reserved.

Association between arterial stiffness and Loa loa microfilaremia in a rural area of the Republic of Congo: A population-based cross-sectional study (the MorLo project).

Loa loa filariasis (loiasis) is still considered a relatively benign disease. However, recent epidemiologic data suggest increased mortality and morbidity in L. loa infected individuals. We aimed to examine whether the density of L. loa microfilariae (mfs) in the blood is associated with cardiovascular disease. Using a point-of-care device (pOpmètre), we conducted a cross-sectional study to assess arterial stiffness and peripheral arterial disease (PAD) in 991 individuals living in a loiasis-endemic rural area in the Republic of the Congo. Microfilaremic individuals were matched for age, sex and village of residence with 2 amicrofilaremic subjects. We analyzed markers of arterial stiffness (Pulse-Wave Velocity, PWV), PAD (Ankle-Brachial Index, ABI) and cardiovascular health (Pulse Pressure, PP). The analysis considered parasitological results (L. loa microfilarial density [MFD], soil-transmitted helminths infection, asymptomatic malaria and onchocerciasis), sociodemographic characteristics and known cardiovascular risk factors (body mass index, smoking status, creatininemia, blood pressure). Among the individuals included in the analysis, 192/982 (19.5%) and 137/976 (14.0%) had a PWV or an ABI considered out of range, respectively. Out of range PWV was associated with younger age, high mean arterial pressure and high L. loa MFD. Compared to amicrofilaremic subjects, those with more than 10,000 mfs/mL were 2.17 times more likely to have an out of range PWV (p = 0.00). Factors significantly associated with PAD were older age, low pulse rate, low body mass index, smoking, and L. loa microfilaremia. Factors significantly associated with an elevation of PP were older age, female sex, high average blood pressure, low pulse rate and L. loa microfilaremia. A potential link between high L. loa microfilaremia and cardiovascular health deterioration is suggested. Further studies are required to confirm and explore this association.

The effect of higher or lower mean arterial pressure on kidney function after cardiac arrest: a post hoc analysis of the COMACARE and NEUROPROTECT trials

BackgroundWe aimed to study the incidence of acute kidney injury (AKI) in out-of-hospital cardiac arrest (OHCA) patients treated according to low-normal or high-normal mean arterial pressure (MAP) targets.MethodsA post hoc analysis of the COMACARE (NCT02698917) and Neuroprotect (NCT02541591) trials that randomized patients to lower or higher targets for the first 36 h of intensive care. Kidney function was defined using the Kidney Disease Improving Global Outcome (KDIGO) classification. We used Cox regression analysis to identify factors associated with AKI after OHCA.ResultsA total of 227 patients were included: 115 in the high-normal MAP group and 112 in the low-normal MAP group. Eighty-six (38%) patients developed AKI during the first five days; 40 in the high-normal MAP group and 46 in the low-normal MAP group (p = 0.51). The median creatinine and daily urine output were 85 μmol/l and 1730 mL/day in the high-normal MAP group and 87 μmol/l and 1560 mL/day in the low-normal MAP group. In a Cox regression model, independent AKI predictors were no bystander cardiopulmonary resuscitation (p < 0.01), non-shockable rhythm (p < 0.01), chronic hypertension (p = 0.03), and time to the return of spontaneous circulation (p < 0.01), whereas MAP target was not an independent predictor (p = 0.29).ConclusionAny AKI occurred in four out of ten OHCA patients. We found no difference in the incidence of AKI between the patients treated with lower and those treated with higher MAP after CA. Higher age, non-shockable initial rhythm, and longer time to ROSC were associated with shorter time to AKI.Clinical trial registration: COMACARE (NCT02698917), NEUROPROTECT (NCT02541591).

Timing of angiotensin receptor-neprilysin inhibitor initiation in patients with heart failure and reduced ejection fraction: data from the Swedish heart failure registry

Abstract Background International guidelines recommend early and fast optimization of the treatments for heart failure with reduced ejection fraction (HFrEF). Angiotensin receptor-neprilyisin inhibitor (ARNI) reduced mortality/morbidity in HFrEF. However, despite early initiation of ARNI appeared safe and of potential benefit in randomized clinical trials, their early implementation is underutilized in real world. Purpose To explore the timing, modalities and predictors of ARNI initiation in a large, nationwide cohort of patients with HFrEF. Methods ARNI-naïve patients with HFrEF (EF&amp;lt;40%) registered in the SwedeHF Registry from January 2017 to December-2021 were included. Separate analyses were performed to investigate ARNI initiation in terms of 1) course of the disease (duration of HF &amp;lt;6 vs ≥6 months), 2) location (in hospital vs out-patient), 3) time from a previous HF hospitalization (in-hospital or ≤14 days from discharge vs 15-90 days vs &amp;gt;90 days or no initiation). Results Analysis 1) Among 16,086 HFrEF patients registered in SwedeHF during the study period, 63% had an HF duration &amp;lt;6 months. 5% vs. 9% of patients with HF duration &amp;lt;6 vs. ≥6 initiated ARNI, respectively. Younger age and referral to specialty care were more strongly associated with ARNI initiation whether HF duration was ≥6 or &amp;lt;6 months. In-patient status, lower EF, and hypertension were independently associated with initiation only if HF duration was &amp;lt;6 months, and HF nurse-led clinic and higher income only if HF duration was ≥6 months. Previous ACEi/ARB use was associated with more likely ARNI initiation in HF duration ≥6 months and less likely initiation in HF duration &amp;lt;6 months (Figure). Analysis 2) Of 1,065 HFrEF patients who initiated ARNI, 30% started as in-patients. Analysis 3) Among 3,892 patients registered as in-patients in SwedeHF, 8% initiated ARNI ≤14 days from the hospital discharge, 4% between 15-90 days, and 88% &amp;gt;90 days or did not initiate. Important independent predictors of earlier initiation (≤14 days) were a more recent registration in SwedeHF, follow-up in specialty care and HF nurse-led clinic, lower EF, worse New York Heart Association class, previous use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEi/ARB), use of mineralocorticoid receptor antagonist, ICD/CRT, and higher income, whereas older age, higher mean arterial pressure, atrial fibrillation (AF), chronic obstructive pulmonary disease (COPD), and living alone where associated with lower likelihood. Conclusions In this nationwide HFrEF cohort ARNI were rarely initiated early at/after an HF hospitalization discharge, initiation was more likely in the out-patient setting and in the later course of the HF disease. Key patient characteristics associated with early initiation were linked with more severe HF and follow-up in dedicated HF care. Overall our data highlight a delayed initiation of ARNI therapy and claim for better implementation in the early stage of HF.Predictors of ARNI initiation

High versus low mean arterial pressure targets after out-of-hospital cardiac arrest: a meta-analysis of randomized controlled trials

Abstract Background Out-of-hospital cardiac arrest (OHCA) is a significant healthcare burden, with an average global incidence of 55 per 100,000 person-years among adults. OHCA patients require blood pressure support to maintain effective mean arterial pressure (MAP) for cerebral reperfusion, which is usually achieved by intravascular fluids and vasopressors in the intensive care unit (ICU). Targeting a specific MAP has been evaluated as a treatment strategy after OHCA; however, the current evidence lacks clear guidelines regarding the optimal MAP target after OHCA. Purpose We aim to evaluate the efficacy of targeting a high MAP (&amp;gt;70 mmHg) versus a low MAP target (&amp;lt; 65 mmHg) after OHCA resuscitation. Methods We conducted a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs), which were retrieved by systematically searching: PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane through January 18th, 2023. Continuous and dichotomous outcomes were pooled using mean difference (MD) and risk ratio (RR) along with confidence interval (CI), using Revman V. 5.4 software. Our review protocol was prospectively published on PROSPERO with ID: CRD42023395333. Results Four RCTs with a total of 1070 patients (531 in the high MAP target group and 534 in the low MAP target group) were included in our analysis. High MAP target was significantly associated with decreased ICU length of stay (MD: -0.78 with a 95 CI [-1.54, -0.02], P= .04) and mechanical ventilation duration (MD: -0.91 with a 95 CI of [-1.51, -0.31], P= .003). However, There was no difference between targeting a high MAP versus low MAP regarding all-cause mortality (RR: 1.07 with a 95% CI [0.91, 1.27], P= 0.4), favorable neurological recovery (cerebral categories scale (CPC) ≤ 2) (RR: 1.02 with a 95% CI [0.93, 1.13], P= 0.68), and neuron-specific enolase (NSE) at 48 hours (MD: 0.54 with 95% CI [-1.67, 2.75], P = 0.63), the incidence of adverse events, including any bleeding (RR: 0.89 with a 95% CI [0.69, 1.36], P= 0.39); arrhythmia (RR: 0.91 with a 95% CI [0.46, 1.82], P= 0.79), or acute kidney injury (RR: 0.80 with a 95% CI [0.36, 1.76] and P = 0.58). Conclusion In patients with OHCA who have been resuscitated, targeting a higher MAP significantly reduced the ICU length of stay and mechanical ventilation, implying potential clinical benefit with an acceptable safety margin. However, there was no difference between targeting a high MAP versus a low MAP regarding all-cause mortality, favorable neurological recovery, and NSE. Therefore, further RCTs are still warranted to elucidate the potential clinical benefit of targeting a high MAP after OHCA before endorsement in clinical practice.Figure 1Figure 2

Hemodynamic evaluation of extremely low birth weight infants during the first 7 days of life

Background and aimWe aimed to investigate the hemodynamic status of extremely low birth weight (ELBW) infants during the transitional period under intensive management. MethodsThis retrospective cohort study analyzed left ventricular ejection fraction (LVEF), left ventricular end-systolic wall stress (ESWS), left ventricular internal dimension in diastole (LVIDd), and mean arterial pressure (MAP) of ELBW infants during their first week of life. Small for gestational age (SGA), histological chorioamnionitis (hCAM), severe intraventricular hemorrhage (IVH), and non-survival to discharge infants were compared to their counterparts. ResultsSixty-two infants (25.7 ± 2.1 weeks, 700.7 ± 165.4 g) were analyzed. MAP gradually increased. Median LVEF was 69.8 % on day 1, decreased to 62.7 % on day 2, then increased throughout the week. ESWS was lowest at birth, rose to 28.2 g/cm2 on day 2, and decreased on day 6. There were no significant changes in LVIDd. SGA infants had higher MAP throughout, higher LVEF on day 2 and 3, but lower LVEF on day 5 to 7. LVIDd was lower in hCAM group. Severe IVH group had a more significant drop in LVEF on day 2, higher ESWS, and a higher incidence of hemodynamic significant patent ductus arteriosus (hsPDA). Non-survival had lower LVIDd. ConclusionsMAP increased gradually. Hemodynamic instability was observed in the first two days, with decreased LVEF and increased ESWS before stabilization. We observed an alteration in hemodynamic adaptation in SGA and hCAM infants. Severe IVH group experienced early hemodynamic instability and a higher incidence of hsPDA.

The relationship between commencement of continuous renal replacement therapy and urine output, fluid balance, mean arterial pressure and vasopressor dose

Background and objectives: The effect of initiating continuous renal replacement therapy (CRRT) on urine output, fluid balance and mean arterial pressure (MAP) in adult intensive care unit (ICU) patients is unclear. We aimed to evaluate the impact of CRRT on urine output, MAP, vasopressor requirements and fluid balance, and to identify factors affecting urine output during CRRT. Design: Retrospective cohort study using data from existing databases and CRRT machines. Setting: Medical and surgical ICUs at a single university-associated centre. Participants: Patients undergoing CRRT between 2015 and 2018. Main outcome measures: Hourly urine output, fluid balance, MAP and vasopressor dose 24 hours before and after CRRT commencement. Missing values were estimated via Kaplan smoothing univariate time-series imputation. Mixed linear modelling was performed with noradrenaline equivalent dose and urine output as outcomes. Results: In 215 patients, CRRT initiation was associated with a reduction in urine output. Multivariate analysis confirmed an immediate urine output decrease (-0.092 mL/kg/h; 95% confidence interval [CI], -0.150 to -0.034 mL/kg/h) and subsequent progressive urine output decline (effect estimate, -0.01 mL/kg/h; 95% CI, -0.02 to -0.01 mL/kg/h). Age and greater vasopressor dose were associated with lower post-CRRT urine output. Higher MAP and lower rates of net ultrafiltration were associated with higher post-CRRT urine output. With MAP unchanged, vasopressor dose increased in the 24 hours before CRRT, then plateaued and declined in the 24 hours thereafter (effect estimate, -0.004 μg/kg/ min per hour; 95% CI, -0.005 to -0.004 μg/kg/min per hour). Fluid balance remained positive but declined towards neutrality following CRRT implementation. Conclusions: CRRT was associated with decreased urine output despite a gradual decline in vasopressor and a positive fluid balance. The mechanisms behind the reduction in urine output associated with commencement of CRRT requires further investigation.

Evidence of serial connection between the plasma volume and two interstitial fluid compartments

BackgroundKinetic analysis of fluid volume shifts can identify two interstitial fluid compartments with different turnover rates, but how they are connected to the bloodstream is unknown. MethodsRetrospective data were retrieved from 217 experiments where 1.5 L of Ringer's solution (mean) had been administered by intravenous infusion over 30 min to awake and anesthetized humans (mean age 40 years). Urinary excretion and hemoglobin-derived plasma dilution served as input variables in a volume kinetic analysis using mixed models software. Possible modes of connection between the two interstitial fluid compartments and the bloodstream were judged by covariance analysis between kinetic rate constants, physiological variables, and time factors. ResultsThe return flow of already distributed fluid to the plasma via a fast-exchange interstitial compartment was inhibited ongoing infusion of fluid (−38 %), which was probably due to increase of the venous pressure during volume loading. Ongoing infusion also greatly retarded the entrance of fluid to the slow-exchange compartment (−85 %), which suggests that infused Ringer's first had to enter the fast-exchange compartment. A high mean arterial pressure markedly increased the urine output and, to a lesser degree, also the rate of entrance of fluid to the fast-exchange compartment. Moreover, a high blood hemoglobin concentration retarded the rate of entrance of fluid to the fast-exchange compartment. ConclusionsThe fast-exchange but not the slow-exchange interstitial fluid compartment was affected by intravascular events, which suggests that only the fast-exchange compartment is directly connected to the circulating blood.

Elevated mean arterial pressure is associated with a lower risk of mortality in acute kidney injury patients receiving continuous renal replacement therapy

Objective maintenance of an appropriate mean arterial pressure (MAP) is important for critically ill patients. However, the association between MAP and prognosis in acute kidney injury (AKI) patients receiving continuous renal replacement therapy (CRRT) is thus far unclear. Materials and methods a total of 1,144 AKI patients who had received CRRT between January 2009 and September 2016 were enrolled and their MAP was measured at CRRT initiation. Patients were categorized into four groups (Quartile 1: MAP < 67.3 mmHg; Quartile 2: 67.3 ≤ MAP < 76.7 mmHg; Quartile 3: 76.7 ≤ MAP < 86.3 mmHg; Quartile 4: MAP ≥ 86.3 mmHg), and 28- and 90-day mortality rates were compared. Results our results demonstrate that 204 (72.1%), 187 (63.4%), 174 (62.6%), and 145 (50.3%) deaths occurred in quartiles 1, 2, 3, and 4 within 28 days, respectively (p < 0.001). This trend also exists in 90-day mortality (Quartile 1: 81.3%; Quartile 2: 72.5%; Quartile 3: 72.3%; Quartile 4: 61.1%, p < 0.001). The Kaplan-Meier results indicate that higher MAP is associated with a reduction in 28- and 90-day mortality (both p < 0.001). After adjusting for potential confounders using Cox proportional hazard regression analysis, higher MAP was still associated with a decline in 28 - and 90-day mortality (both p < 0.001). Conclusion MAP is a valuable parameter for predicting mortality in AKI patients who are receiving CRRT.

Hepatic recompensation according to Baveno VII criteria is linked to a significant survival benefit in decompensated alcohol-related cirrhosis.

Removing the primary aetiological factor in decompensated cirrhosis may lead to a restoration of hepatic function. In this study, we investigated the clinical implications of recompensation and the subsequent survival in patients with decompensated alcohol-related cirrhosis. The rate of recompensation was evaluated in patients with decompensated alcohol-related cirrhosis and persistent alcohol abstinence undergoing a hepatic venous pressure gradient (HVPG) measurement. Recompensation was defined according to Baveno VII criteria as resolution of ascites and hepatic encephalopathy, absence of variceal bleeding and improvement in liver function. Two hundred and four abstinent patients with decompensated alcohol-related cirrhosis (age: 57.2 [IQR:50.1-63.7] years; 75.0% male; median MELD: 15 [IQR:11-19]) and a median HVPG of 20 (IQR:18-24) mmHg were included. During a median follow-up of 24.4 (IQR:10.9-50.4) months, 37 patients (18.1%) achieved abstinence-induced recompensation. Lower baseline HVPG, lower Child-Pugh score, lower BMI, higher albumin and higher mean arterial pressure were linked to a higher probability of recompensation. After adjusting for age, disease severity, portal hypertension and systemic inflammation, achieving recompensation resulted in a significant and considerable reduction in liver-related mortality (adjusted HR: 0.091 [95% CI: 0.012-0.677]; p = .019). Only 13 patients (6.4%) developed hepatocellular carcinoma, with a tendency towards a lower risk upon recompensation (HR: 0.398 [95% CI: 0.084-1.878]; p = .245), yet this finding did not reach statistical significance and requires further investigation. Alcohol abstinence led to recompensation in 18.1% of our cohort of HVPG-characterised patients with decompensated alcohol-related cirrhosis. Achieving hepatic recompensation resulted in a >90% risk reduction in liver-related mortality.

Clinicopathological Characteristics and Impacts on Clinical Outcomes of Thrombotic Microangiopathy Lesions in Patients with Immunoglobulin A Nephropathy in Thailand

Introduction: More reports of thrombotic microangiopathy (TMA) in immunoglobulin A (IgA) nephropathy suggest its association with poor clinical outcomes. However, the prevalence and clinical significance of TMA in IgA nephropathy have not been widely studied in different populations. Methods: Kidney biopsies of all patients with primary IgA nephropathy from 1995 to 2015 at the King Chulalongkorn Memorial Hospital, Thailand, were retrospectively reviewed and reclassified by two pathologists following the Oxford MEST-C classification. TMA lesions were detected based solely on light microscopic findings. Associations between the presence of TMA and clinical data, other pathologic findings, and clinical outcomes were studied. Results: Among 267 patients with primary IgA nephropathy, 166 had adequate clinical data and kidney tissues for the analysis. TMA was observed in 21 patients (13%) and was associated with higher mean arterial pressure (MAP), history of malignant hypertension, higher proteinuria, and lower estimated glomerular filtration rate (eGFR) at diagnosis compared to those without TMA. According to the Oxford MEST-C classification, TMA showed a significant association with severe tubular atrophy/interstitial fibrosis (T2) but not with mesangial hypercellularity (M1), endocapillary hypercellularity (E1), segmental glomerulosclerosis (S1), or crescents (C1–2). After a median follow-up of 50 months, patients with TMA had a significantly higher risk of progression to end-stage kidney disease (ESKD) (hazard ratio [HR] 5.8, 95% confidence interval [CI]: 3.1–10.9) and all-cause mortality (HR 3.4, 95% CI: 1.3–8.8). After adjusting for baseline eGFR, MAP, proteinuria, and other pathological lesions, TMA remained an independent predictor of ESKD (adjusted HR 2.4, 95% CI: 1.1–5.4). Conclusions: Kidney TMA in IgA nephropathy is associated with advanced disease stages, carries a poor prognosis, and thus should be considered in the pathological classification of IgA nephropathy.

Maternal and Offspring Cardiovascular Function following Pregnancy with Hypertensive Disorder.

Hypertensive disorders of pregnancy (HDP) have been associated with increased cardiovascular risk for the mother and her offspring. However, it remains unknown whether cardiovascular changes are present in the postpartum period. This was a cross-sectional study of women with singleton pregnancies. We recruited 33 women (20 following preeclampsia and 13 following gestational hypertension) and an equal number of women with uncomplicated pregnancy. Conventional and more advanced echocardiographic modalities such as speckle tracking were used to assess maternal and offspring cardiac function at 3-9 months postpartum. In women with HDP compared to those without, there was higher mean arterial pressure (mean 92.3 (SD 7.3) vs. 86.8 (8.3) mmHg, p = 0.007), left-ventricular mass indexed for body-surface area (64.5 (10.5) vs. 56.8 (10.03), p < 0.003), and E/e' (3.6 (0.8) vs. 3.1 (0.9), p = 0.022). There were no significant differences between groups in maternal left-ventricular systolic-functional indices and in offspring cardiac function between groups. At 3-9 months postpartum, mothers with HDP had higher blood pressure, higher left-ventricular mass, and reduced left-ventricular diastolic function. However, in their offspring, cardiac function was preserved. These findings suggest that mothers who experienced an HDP would benefit from cardio-obstetric follow-up in the postpartum period.

High-normal versus low-normal mean arterial pressure thresholds in critically ill patients: a systematic review and meta-analysis of randomized trials.

Targeted blood pressure thresholds remain unclear in critically ill patients. Two prior systematic reviews have not shown differences in mortality with a high mean arterial pressure (MAP) threshold, but there have been new studies published since. Thus, we conducted an updated systematic review and meta-analysis of randomized controlled trials (RCTs) that compared the effect of a high-normal vs low-normal MAP on mortality, favourable neurologic outcome, need for renal replacement therapy, and adverse vasopressor-induced events in critically ill patients. We searched six databases from inception until 1 October 2022 for RCTs of critically ill patients targeted to either a high-normal vs a low-normal MAP threshold for at least 24 hr. We assessed study quality using the revised Cochrane risk-of-bias 2 tool and the risk ratio (RR) was used as the summary measure of association. We used the Grading of Recommendations Assessment, Development, and Evaluation framework to assess the certainty of evidence. We included eight RCTs with 4,561 patients. Four trials were conducted in patients following out-of-hospital cardiac arrest, two in patients with distributive shock requiring vasopressors, one in patients with septic shock, and one in patients with hepatorenal syndrome. The pooled RRs for mortality (eight RCTs; 4,439 patients) and favourable neurologic outcome (four RCTs; 1,065 patients) were 1.06 (95% confidence interval [CI], 0.99 to 1.14; moderate certainty) and 0.99 (95% CI, 0.90 to 1.08; moderate certainty), respectively. The RR for the need for renal replacement therapy (four RCTs; 4,071 patients) was 0.97 (95% CI, 0.87 to 1.08; moderate certainty). There was no statistical between-study heterogeneity across all outcomes. This updated systematic review and meta-analysis of RCTs found no differences in mortality, favourable neurologic outcome, or the need for renal replacement therapy between critically ill patients assigned to a high-normal vs low-normal MAP target. PROSPERO (CRD42022307601); registered 28 February 2022.