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Purpose: We compared the adaptive responses to supramaximal high-intensity interval training (HIIT) individualized according to anaerobic speed reserve (ASR), the 30-15 Intermittent Fitness Test (VIFT), and velocity associated with maximum oxygen uptake (MAS) to determine which approach facilitates more identical adaptations across athletes with different profiles. Methods: Thirty national-level basketball players (age = 28.4 [5] y; body mass = 88.9 [6.3] kg; height = 190 [4.8] cm) were randomly assigned to 3 training groups performing 2 sets of 4, 6, 8, 6, 8, and 10-minute runs (from first to sixth week, respectively), consisting of 15-second running at Δ%20ASR (MAS + 0.2 × ASR), 95%VIFT, and 120%MAS, with 15 seconds recovery between efforts and a 3-minute relief between sets. Results: All 3 interval interventions significantly (P <.05) enhanced maximum oxygen uptake ( V ˙ O 2 max), oxygen pulse ( V ˙ O 2 / HR), first and second ventilatory threshold (VT1 and VT2), cardiac output ( Q ˙ max ), stroke volume, peak and average power output, testosterone levels, and testosterone-to-cortisol ratio following the training period. Different values of interindividual variability (coefficient of variation) for the percentage changes of the measured variables were observed in response to HIITASR, HIITvIFT, and HIITMAS for V ˙ O 2 max (8.7%, 18.8%, 34.6%, respectively), V ˙ O 2 / HR (9.5%, 15.0%, 28.6%), VT1 (9.6%, 19.6%, 34.6%), VT2 (21.8%, 32.4%, 56.7%), Q ˙ max (8.2%, 16.9%, 28.8%), stroke volume (7.9%, 15.2%, 23.5%), peak power output (20%, 22%, 37.3%), average power output (21.1%, 21.3%, 32.5%), testosterone (52.9%, 61.6%, 59.9%), and testosterone-to-cortisol ratio (55.1%, 59.5%, 57.8%). Conclusions: Supramaximal HIIT performed at Δ%20ASR resulted in more uniform physiological adaptations than HIIT interventions prescribed using VIFT or MAS. Although hormonal changes do not follow this approach, all the approaches induced an anabolic effect. [ABSTRACT FROM AUTHOR]

Fluid bolus therapy (FBT) is fundamental to the management of circulatory shock in critical care but balancing the benefits and toxicities of FBT has proven challenging in individual patients. Improved predictors of the hemodynamic response to a fluid bolus, commonly referred to as a fluid challenge, are needed to limit non-beneficial fluid administration and to enable automated clinical decision support and patient-specific precision critical care management. In this study we retrospectively analyzed data from 394 fluid boluses from 58 pigs subjected to either hemorrhagic or distributive shock. All animals had continuous blood pressure and cardiac output monitored throughout the study. Using this data, we developed a machine learning (ML) model to predict the hemodynamic response to a fluid challenge using only arterial blood pressure waveform data as the input. A Random Forest binary classifier referred to as the ML fluid responsiveness algorithm (MLFRA) was trained to detect fluid responsiveness (FR), defined as a ≥ 15% change in cardiac stroke volume after a fluid challenge. We then compared its performance to pulse pressure variation, a commonly used metric of FR. Model performance was assessed using the area under the receiver operating characteristic curve (AUROC), confusion matrix metrics, and calibration curves plotting predicted probabilities against observed outcomes. Across multiple train/test splits and feature selection methods designed to assess performance in the setting of small sample size conditions typical of large animal experiments, the MLFRA achieved an average AUROC, recall (sensitivity), specificity, and precision of 0.82, 0.86, 0.62. and 0.76, respectively. In the same datasets, pulse pressure variation had an AUROC, recall, specificity, and precision of 0.73, 0.91, 0.49, and 0.71, respectively. The MLFRA was generally well-calibrated across its range of predicted probabilities and appeared to perform equally well across physiologic conditions. These results suggest that ML, using only inputs from arterial blood pressure monitoring, may substantially improve the accuracy of predicting FR compared to the use of pulse pressure variation. If generalizable, these methods may enable more effective, automated precision management of critically ill patients with circulatory shock.

Cardiogenic shock is a complex syndrome defined by systemic hypoperfusion and inadequate cardiac output arising from a wide array of underlying causes. Although the understanding of cardiogenic shock epidemiology, specific subphenotypes, haemodynamics, and cardiogenic shock severity staging has evolved, few therapeutic interventions have shown survival benefit. Results from seminal randomised controlled trials support early revascularisation of the culprit vessel in infarct-related cardiogenic shock and provide evidence of improved survival with the use of temporary circulatory support in selected patients. However, numerous questions remain unanswered, including optimal pharmacotherapy regimens, the role of mechanical circulatory support devices, management of secondary organ dysfunction, and best supportive care. This Review summarises current definitions, pathophysiological principles, and management approaches in cardiogenic shock, and highlights key knowledge gaps to advance individualised shock therapy and the evidence-based ethical use of modern technology and resources in cardiogenic shock. [ABSTRACT FROM AUTHOR]

As more women engage in high-altitude activities, understanding how ovarian hormone fluctuations affect their cardiorespiratory system is essential for optimizing acclimatization to these environments. This study investigates the effects of menstrual cycle (MC) phases on physiological responses at rest, during and after submaximal exercise, at high-altitude (barometric pressure 509 ± 6 mmHg; partial pressure of inspired oxygen 96 ± 1 mmHg; ambient temperature 21 ± 2 °C and relative humidity 27 ± 4%) in 16 eumenorrheic women. Gas exchange, hemodynamic responses, heart rate variability and heart rate recovery (HRR) were monitored at low altitude, and then at 3375 m on the Mont Blanc (following nocturnal exposure) during both the early-follicular (EF) and mid-luteal (ML) phases. Significant differences were observed between low and high-altitude in ventilation, heart rate and cardiac output. Resting ventilation (15.2 ± 1.9 vs. 13.2 ± 2.5 L.min-1; p = 0.039) and tidal volume (812 ± 217 vs. 713 ± 190 mL; p = 0.027) were higher during EF than ML at high-altitude. These differences between EF and ML were no longer evident during exercise, with comparable responses in oxygen uptake kinetics, cycling efficiency and HRR. The MC had negligible effects on physiological responses to high-altitude. An individualized approach, tailored to each woman's specific responses to hypoxia across the MC, may be more beneficial in optimizing high-altitude sojourns than general guidelines. [ABSTRACT FROM AUTHOR]

Background and Purpose: Endothelin‐1 (ET‐1) receptor A (ETA) antagonists reduce proteinuria and prevent renal outcomes in chronic kidney disease (CKD) patients, but their utility has been limited because of associated fluid retention, resulting in increased heart failure risk. Understanding the mechanisms responsible for fluid retention could result in solutions that preserve renoprotective effects while mitigating fluid retention, but the complexity of the endothelin system has made identification of the underlying mechanisms challenging. Approach: We utilized a previously developed mathematical model of ET‐1 kinetics, ETA receptor antagonism, kidney function, haemodynamics, and sodium and water homeostasis to evaluate hypotheses for mechanisms of fluid retention with ETA antagonism. To do this, we simulated the RADAR clinical trial of atrasentan in patients with type 2 diabetes and CKD and evaluated the ability of the model to predict the observed decreases in haematocrit, urine albumin creatinine ratio (UACR), mean arterial pressure (MAP), and estimated glomerular filtration rate (eGFR). Background and Key Results: An effect of ETA antagonism on venodilation and increased venous capacitance was found to be the critical mechanism necessary to reproduce the simultaneous decrease in both MAP and haematocrit observed in RADAR. Conclusions and Impact: These findings indicate that fluid retention with ETA antagonism may not be caused by a direct antidiuretic effect within the kidney but is instead be an adaptive response to venodilation and increased venous capacity, which acutely tends to reduce cardiac filling pressure and cardiac output, and that fluid retention occurs in an attempt to maintain cardiac filling and cardiac output. [ABSTRACT FROM AUTHOR]

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) is a major cause of morbidity and mortality in patients with type 2 diabetes (T2D). Acute increases in circulating levels of ketone body 3-hydroxybutyrate have beneficial acute hemodynamic effects in patients without T2D with chronic heart failure with reduced ejection fraction. However, the cardiovascular effects of prolonged oral ketone ester (KE) treatment in patients with T2D and HFpEF remain unknown. METHODS: A total of 24 patients with T2D and HFpEF completed a 6-week randomized, double-blind crossover study. All patients received 2 weeks of KE treatment (25 g D-ß-hydroxybutyrate-(R)-1,3-butanediol × 4 daily) and isocaloric and isovolumic placebo, separated by a 2-week washout period. At the end of each treatment period, patients underwent right heart catheterization, echocardiography, and blood samples at trough levels of intervention, and then during a 4-hour resting period after a single dose. A subsequent second dose was administered, followed by an exercise test. The primary end point was cardiac output during the 4-hour rest period. RESULTS: During the 4-hour resting period, circulating 3-hydroxybutyrate levels were 10-fold higher after KE treatment (1010±56 μmol/L; P<0.001) compared with placebo (91±55 μmol/L). Compared with placebo, KE treatment increased cardiac output by 0.2 L/min (95% CI, 0.1 to 0.3) during the 4-hour period and decreased pulmonary capillary wedge pressure at rest by 1 mm Hg (95% CI, -2 to 0) and at peak exercise by 5 mm Hg (95% CI, -9 to -1). KE treatment decreased the pressure-flow relationship (Δ pulmonary capillary wedge pressure/Δ cardiac output) significantly during exercise (P<0.001) and increased stroke volume by 10 mL (95% CI, 0 to 20) at peak exercise. KE right-shifted the left ventricular end-diastolic pressure-volume relationship, suggestive of reduced left ventricular stiffness and improved compliance. Favorable hemodynamic responses of KE treatment were also observed in patients treated with sodium-glucose transporter-2 inhibitors and glucagon-like peptide-1 analogs. CONCLUSIONS: In patients with T2D and HFpEF, a 2-week oral KE treatment increased cardiac output and reduced cardiac filling pressures and ventricular stiffness. At peak exercise, KE treatment markedly decreased pulmonary capillary wedge pressure and improved pressure-flow relationship. Modulation of circulating ketone levels is a potential new treatment modality for patients with T2D and HFpEF. [ABSTRACT FROM AUTHOR]

Background: Enhancing venous return during cardiopulmonary resuscitation (CPR) can lead to better hemodynamics and improved outcome after cardiac arrest (CA). Peripheral Intravenous Analysis (PIVA) provides feedback on venous flow changes and may indicate an increase in venous return and cardiac output during CPR. We hypothesize PIVA can serve as an early indicator of increased venous return, preceding end-tidal CO2 (etCO2) increase, before the return of spontaneous circulation (ROSC) in a rat model of CA and CPR. Results: Eight male Wistar rats were intubated and ventilated, and etCO2 was measured. Vessels were cannulated in the tail vein, femoral vein, femoral artery, and central venous and connected to pressure transducers. Ventilation was discontinued to achieve asphyxial CA. After 8 min, CPR began with ventilation, epinephrine, and automated chest compressions 200 times per minute until mean arterial pressure increased to 120 mmHg. Waveforms were recorded and analyzed. PIVA was calculated using a Fourier transformation of venous waveforms. Data are mean ± SE. Maximum PIVA values occurred in the tail vein 34.7 ± 2.9 s before ROSC, with subsequent PIVA peaks in femoral vein and centrally at 30.9 ± 5.4 and 25.1 ± 5.0 s, respectively. All PIVA peaks preceded etCO2 increase (21.5 ± 3.2 s before ROSC). Conclusion: PIVA consistently detected venous pressure changes prior to changes in etCO2. This suggests that PIVA has the potential to serve as an important indicator of venous return and cardiac output during CPR, and also as a predictor of ROSC. [ABSTRACT FROM AUTHOR]

Background: Intraoperation hypotension (IOH) is commonly observed in patients undergoing surgery under general anesthesia, and even a brief episode of IOH can lead to unfavorable outcomes. To reduce the risk, blood pressure is closely measured during general anesthesia, and norepinephrine (NE) is frequently administered if hypotension is detected. Despite its routine application, information on the dose-exposure-response relationship of NE remains limited. Additionally, quantification of the influence of general anesthesia on the pharmacokinetics (PK) of NE is lacking. Objective: In this study, we aimed to describe NE PK in healthy volunteers and the influence of general anesthesia on its PK. Methods: A single-center, cross-over study was conducted in healthy volunteers. The volunteers received a step-up NE dosing scheme (0.04, 0.08, 0.12, 0.16 and 0.20 mcg–1/kg–1/min–1) first in the awake state and then under general anesthesia. General anesthesia was administered using a propofol/remifentanil Eleveld target-controlled infusion. During general anesthesia, a 30-second electrical stimulus was given as surrogate for surgical incision to the volunteers at each dosage step. Blood samples were drawn before the initial dosing and after each dosing step, and plasma NE, propofol and remifentanil concentrations were subsequently determined. A population PK model was developed using non-linear mixed effects modelling. Simulations were conducted to predict the plasma NE concentration in patients at different measured propofol concentrations. Results: A total of 1219 samples were analyzed from 36 volunteers. A two-compartment model with a first-order elimination best described the data. Weight, age, and session effect (awake vs general anesthesia) were identified as relevant covariates on the clearance (CL) of NE. A 10% decrease in NE CL was observed after general anesthesia induction. This difference between sessions is better explained by the measured concentration of propofol, rather than the anticipated impact of cardiac output. The estimated post-stimulation NE concentration is 0.66 nmol/L–1 (95% CI 0.06–1.20 nmol/L–1) lower than the pre-stimulation NE concentration. Model simulation indicates that patients at a higher measured propofol concentration (e.g., 6 mcg/mL–1) exhibited higher NE concentrations (95% PI 18.10–43.89 nmol/L–1) than patients at a lower measured propofol concentration (e.g., 3 mcg/mL–1) (95% PI 16.81–38.91 nmol L–1). Conclusion: The NE PK is well described with a two-compartment model with a first-order elimination. NE CL exhibiting a 10% decrease under general anesthesia, with this difference being attributed to the measured concentration of propofol. The impact of stimulation on NE PK under general anesthesia is very limited. Clinical Trials Registration Number: NL9312. [ABSTRACT FROM AUTHOR]

Space flight modulates the functions of the cardiovascular system. The exposure to space conditions can alter the cerebral blood flow, as well as the venous return. Anemia, cardiac output changes, and increased activity of the sympathetic nervous system can also be seen. Understanding cardiac changes prepares astronauts for both better in-flight adaptations and long-term protection against cardiovascular diseases. The heart could undergo radio-degenerative effects when exposed to space radiation, increasing the risk of cardiovascular diseases in the long run. A high frequency of arrhythmias, such as ventricular/atrial premature complexes, have been reported during the Gemini and Apollo missions. Additionally, microgravity can lead to progressive degeneration of the myocytes and muscle atrophy with altered gene expression and calcium handling, along with impaired contractility. This review summarizes the potential cardiovascular effects of spaceflight and prevention measures. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess the performance of transpulmonary thermodilution (TPTD) using room-temperature saline (CORT) and waveform-derived continuous CO (CCO) compared with TPTD using iced saline (COICED) as the indicator for measurements of CO in isoflurane-anesthetized dogs. METHODS: 8 Beagles aged 1 to 2 years (7.4 to 11.2 kg) were enrolled in this experimental study from March 21 to 31, 2023. Dogs were anesthetized with 0.01 mg/kg acepromazine, 5 to 6 mg/kg propofol, and isoflurane and were mechanically ventilated. Dogs were instrumented with a central venous catheter and a femoral arterial catheter equipped with a thermistor. The COICED, CORT, and pulse wave-derived CCO values were obtained at baseline, during infusions of phenylephrine and norepinephrine, and during blood withdrawal and replacement. Data were analyzed with a mixed effect model, Bland-Altman plots, and concordance. Percent error was calculated. P < .05 was used for significance. RESULTS: Data were collected from 8 dogs. Significant effects of time and the interaction of time and method were found. Bland-Altman plots showed negligible bias with limits of agreement between -0.35 and 0.25 L/min for CORT versus COICED and -1.23 and 1.15 L/min for CCO versus COICED. Percent errors were 17.7% and 66.6%, respectively. In the 4-quadrant plots, the concordance rate was 95% and 68% for measurements obtained with CORT and for CCO, respectively. CONCLUSIONS: Transpulmonary thermodilution using room temperature saline was accurate and able to track changes in CO. Continuous CO had a large percent error and low tracking ability. CLINICAL RELEVANCE: Transpulmonary thermodilution using room temperature saline is reliable for monitoring CO and obviates the need for iced preparations in clinical scenarios. [ABSTRACT FROM AUTHOR]

The present investigation aimed to study the cardiovascular responses and the cerebral oxygenation (Cox) during exercise in acute hypoxia and with contemporary mental stress. Fifteen physically active, healthy males (age 29.0 ± 5.9 years) completed a cardiopulmonary test on a cycle ergometer to determine the workload at their gas exchange threshold (GET). On a separate day, participants performed two randomly assigned exercise tests pedaling for 6 min at a workload corresponding to 80% of the GET: (1) during normoxia (NORMO), and (2) during acute, normobaric hypoxia at 13.5% inspired oxygen (HYPO). During the last 3 min of the exercise, they also performed a mental task (MT). Hemodynamics were assessed with impedance cardiography, and peripheral arterial oxygen saturation and Cox were continuously measured by near-infrared spectroscopy. The main results were that both in NORMO and HYPO conditions, the MT caused a significant increase in the heart rate and ventricular filling rate. Moreover, MT significantly reduced (74.8 ± 5.5 vs. 62.0 ± 5.2 A.U.) Cox, while the reaction time (RT) increased (813.3 ± 110.2 vs. 868.2 ± 118.1 ms) during the HYPO test without affecting the correctness of the answers. We conclude that in young, healthy males, adding an MT during mild intensity exercise in both normoxia and acute moderate (normobaric) hypoxia induces a similar hemodynamic response. However, MT and exercise in HYPO cause a decrease in Cox and an impairment in RT. [ABSTRACT FROM AUTHOR]

Babies born with fetal growth restriction (FGR) are at higher risk of developing cardiometabolic diseases across the life course. The reduction in substrate supply to the developing fetus that causes FGR not only alters cardiac growth and structure but may have deleterious effects on metabolism and function. Using a sheep model of placental restriction to induce FGR, we investigated key cardiac metabolic and functional markers that may be altered in FGR. We also employed phase‐contrast magnetic resonance imaging MRI to assess left ventricular cardiac output (LVCO) as a measure of cardiac function. We hypothesized that signalling molecules involved in cardiac fatty acid utilisation and contractility would be impaired by FGR and that this would have a negative impact on LVCO in the late gestation fetus. Key glucose (GLUT4 protein) and fatty acid (FATP, CD36 gene expression) substrate transporters were significantly reduced in the hearts of FGR fetuses. We also found reduced mitochondrial numbers as well as abundance of electron transport chain complexes (complexes II and IV). These data suggest that FGR diminishes metabolic and mitochondrial capacity in the fetal heart; however, alterations were not correlated with fetal LVCO. Overall, these data show that FGR alters fetal cardiac metabolism in late gestation. If sustained ex utero, this altered metabolic profile may contribute to poor cardiac outcomes in FGR‐born individuals after birth. Key points: Around the time of birth, substrate utilisation in the fetal heart switches from carbohydrates to fatty acids. However, the effect of fetal growth restriction (FGR) on this switch, and thus the ability of the fetal heart to effectively metabolise fatty acids, is not fully understood.Using a sheep model of early onset FGR, we observed significant downregulation in mRNA expression of fatty acid receptors CD36 and FABP in the fetal heart. FGR fetuses also had significantly lower cardiac mitochondrial abundance than controls.There was a reduction in abundance of complexes II and IV within the electron transport chain of the FGR fetal heart, suggesting altered ATP production.This indicates reduced fatty acid metabolism and mitochondrial function in the heart of the FGR fetus, which may have detrimental long‐term implications and contribute to increased risk of cardiovascular disease later in life. [ABSTRACT FROM AUTHOR]

Objective: To compare maternal vascular indices and hemodynamic parameters at 35–37 weeks' gestation in pregnancies complicated by gestational diabetes mellitus (GDM), those with pre‐existing diabetes mellitus (DM) and those without GDM or pre‐existing DM. Methods: This was a prospective observational study in women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. The visit included recording of maternal demographic characteristics and medical history, and measurement of vascular indices and hemodynamic parameters using a non‐invasive operator‐independent device. These included carotid‐to‐femoral pulse‐wave velocity, augmentation index, cardiac output, stroke volume, central systolic and diastolic blood pressure, total peripheral resistance and heart rate. The values in the GDM and pre‐existing DM groups were compared to those in the unaffected group. Results: We examined 6746 women, of whom 396 were excluded because they had chronic hypertension or developed pre‐eclampsia or gestational hypertension. The study population of 6350 pregnancies contained 99 (1.6%) with pre‐existing Type‐I or Type‐II DM and 617 (9.7%) that developed GDM, including 261 (42.3%) that were treated with diet alone, 239 (38.7%) treated with metformin alone and 117 (19.0%) treated with insulin with or without metformin. Among women with GDM and those with pre‐existing DM, compared to those without GDM or pre‐existing DM, there was a higher median cardiac output and heart rate, central systolic and diastolic blood pressure and pulse‐wave velocity, but there was no significant difference in stroke volume or total peripheral resistance. There were no significant differences within the GDM group according to treatment type, except for higher heart rate in women treated with metformin alone compared to the group treated with diet alone. Conclusion: Women with GDM and those with pre‐existing DM have evidence of early vascular disease in the third trimester, and this may contribute to their increased long‐term cardiovascular risk. © 2024 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The objectives of our systematic review and meta-analyses were to determine the diagnostic accuracy of central venous oxygen saturation (Scvo2) in estimating mixed venous oxygen saturation (Svo2) and cardiac index in critically ill patients. DATA SOURCES: A systematic search using MEDLINE, Cochrane Central Register of Controlled Trials, and Embase was completed on May 6, 2024. STUDY SELECTION: Studies of patients in the ICU for whom Scvo2 and at least one reference standard test was performed (thermodilution and/or Svo2) were included. DATA EXTRACTION: Individual patient data were used to calculate the pooled intraclass correlation coefficient (ICC) for Svo2 and Spearman correlation for cardiac index. The Quality Assessment of Diagnostic Accuracy Studies-2 and Grading Recommendations Assessment, Development, and Evaluation tools were used for the risk of bias and certainty of evidence assessments. DATA SYNTHESIS: Of 3427 studies, a total of 18 studies with 1971 patients were identified. We meta-analyzed 16 studies (1335 patients) that used Svo2 as a reference and three studies (166 patients) that used thermodilution as reference. The ICC for reference Svo2 was 0.83 (95% CI, 0.75-0.89) with a mean difference of 2.98% toward Scvo2. The Spearman rank correlation for reference cardiac index is 0.47 (95% CI, 0.46-0.48; p < 0.0001). CONCLUSIONS: There is moderate reliability for Scvo2 in predicting Svo2 in critical care patients with variability based on sampling site and presence of sepsis. There is limited evidence on the independent use of Scvo2 in predicting cardiac index. [ABSTRACT FROM AUTHOR]

Acute right ventricular failure (RVF) is prevalent in multiple disease states and is associated with poor clinical outcomes. Right-sided temporary mechanical circulatory support (tMCS) devices are used to unload RV congestion and increase cardiac output in cardiogenic shock (CS) with hemodynamically significant RVF. Several RV-tMCS device platforms are available; however consensus is lacking on patient selection, timing of escalation to RV-tMCS, device management, and device weaning. The purposes of this review are to 1) describe the current state of tMCS device therapies for acute RVF with CS, 2) discuss principles of escalation to RV-tMCS device therapy, 3) examine important aspects of clinical management for patients supported by RV-tMCS devices including volume management, anticoagulation, and positive pressure ventilation, and 4) provide a framework for RV-tMCS weaning. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate the presence of aortic isthmus flow reversal and its associated factors in fetuses with positive and false‐positive coarctation of the aorta (CoA) compared with normal controls. Material and Methods: Pregnant women with fetuses suspected of CoA and normal control were enrolled, and these women experienced prenatal ultrasound scan and followed up for 6 months after birth to confirm the presence of CoA. All the ultrasound parameters were analyzed. Results: A total of 134 pregnant women were enrolled, with 43 CoA‐positive fetuses and 91 CoA false‐positive fetuses, and 334 matched pregnant women were enrolled in the control group. Aortic isthmus flow reversal occurred in 28 (65.1%) fetuses in the CoA‐positive group, significantly (p < 0.05) more than in the false‐positive (37 or 40.7%) or control group (64 or 19.2%). Aortic isthmus flow reversal was mostly in the full systole (n = 17 or 60.7%) or late systole and early‐middle diastole (n = 10 or 35.7%) in the CoA‐positive fetuses (n = 27 or 96.4%), significantly (p < 0.001) different from that in the false‐positive or control group. The aortic isthmus flow reversal peak systolic velocity (PSV), flow volume, and ratio of reversed flow/forward flow were significantly (p < 0.05) increased in the CoA‐positive and false‐positive groups than in the control group. The aortic isthmus flow reversal incidence was significantly (p < 0.05) correlated with the middle cerebral artery (MCA) PSV in the total three groups or in the false‐positive group but was significantly (p < 0001) negatively correlated with the MCA resistance index (RI) in the CoA‐positive group. The incidence of the aortic isthmus flow reversal was significantly (p < 0.05) positively correlated with the umbilical artery (UA) RI in the false‐positive group and with the UA RI in the total three groups. Independently associated factors for aortic isthmus flow reversal were isthmic flow volume/CCO (combined cardiac output) in the CoA‐positive group. Conclusions: Reversal of flow in the aortic isthmus is much more common in true‐positive cases of CoA as compared to controls, and isthmic flow reversal in the full systolic phase only suggests presence of CoA. The aortic isthmic reversed flow volume accounts for over half of the isthmic forward flow volume in the CoA‐positive fetuses than in the normal controls. [ABSTRACT FROM AUTHOR]

To characterize the correlation, agreement and concordance of cardiac output (CO) measured with transthoracic ultrasound and the correlation and concordance of aortic blood flow (ABF) minute distance (MD) measured by transesophageal Doppler with CO measured by pulmonary artery thermodilution (PATD) in cats. Experimental study. A group of six healthy male neutered cats, aged 2–8 years and weighing 5.3 ± 0.3 kg. Cats were anesthetized with isoflurane in oxygen. CO was measured by PATD (CO PATD) and transthoracic echocardiography (CO ECHO). ABF MD was measured using an esophageal Doppler flow probe aligned with descending ABF. All measurements were made under three conditions: dexmedetomidine (20 μg kg–1) intravenously; atipamezole (200 μg kg–1) intramuscularly and atropine (20 μg kg–1) intravenously as needed to achieve a minimum heart rate of 140 beats minute–1; and dopamine (20 μg kg–1 minute–1) intravenously in that order. Correlation between CO PATD and CO ECHO , and CO PATD and Doppler MD was evaluated using repeated measures correlation. Agreement between CO PATD and CO ECHO was evaluated using Bland–Altman method. Differences between consecutive pairs of CO measurements were calculated for concordance analysis. Correlation between CO PATD and CO ECHO and between CO PATD and MD was significant (p < 0.001), with correlation coefficients greater than 0.92. A bias of > 27% and upper limits of agreement of 66% were found between CO PATD and CO ECHO. Concordance rate with CO PATD was 76–80% for CO ECHO and 72% for MD. Echocardiographic methods for the measurement of CO showed poor agreement and concordance with PATD. MD showed poor concordance with PATD. As such, these methods cannot be used as an alternative to PATD nor can they appropriately track changes in CO in anesthetized cats. [ABSTRACT FROM AUTHOR]

Extracorporeal membrane oxygenator (ECMO) is a well-established therapy for respiratory failure. Refractory hypoxemia, despite the use of ECMO, remains a challenging problem. The ECMO circuit may not provide enough oxygenation support in the presence of high cardiac output, increased physiologic demand, and impaired gas exchange. Adding a second ECMO oxygenator using the same pump (sometimes needing a second drainage cannula) can improve oxygenation and facilitate lung-protective ventilation in selected patients. We describe a 3-patient series with severe ARDS secondary to SARS-CoV-2 infection and refractory hypoxemia during ECMO support successfully treated with this approach. [ABSTRACT FROM AUTHOR]

Introduction: Most patients on extracorporeal membrane oxygenation (ECMO) decease during therapy on the system. However, the actual causes of death have not been studied sufficiently. This study analyses the etiology, prevalence, and risk factors for the outcome variable death during ongoing ECMO for all patients and divided according to venoarterial (VA) or venovenous (VV) support. Methods: We retrospectively analysed all patients receiving ECMO support at our institution between March 2006 to January 2021. Only the patients deceased during ongoing support were included. Results: 2016 patients were placed on VA (n = 1168; 58%) or VV (n = 848; 42%) ECMO; 759 patients (37.7%) deceased on support. The causes of death differed between the support types: VA ECMO patients mostly died from cerebral ischemia (34%), low-cardiac output (LCO; 24.1%) and multi-organ failure (MOF; 21.6%), whereas in VV ECMO cases, refractory respiratory failure (28.2%), and sepsis (20.4%) dominated. Multivariate regression analysis revealed cardiopulmonary resuscitation (CPR) and acidosis prior to ECMO as risk factors for dying on VA ECMO, while high inotropic doses pre-ECMO, a high fraction of inspired oxygen on day 1, elevated lactate dehydrogenase, and international normalized ratio levels lead to an unfavourable outcome in VV ECMO patients. Conclusion: Even in highly experienced centers, ECMO mortality remains high and occurs mainly on support or 24 h after its termination. The causes of death differ between VV and VA ECMO, depending on the underlying diseases responsible for the need of extracorporeal support. [ABSTRACT FROM AUTHOR]

Previous research suggested that exposure to long‐lasting or repeated laboratory stressors may lead to rearrangement of cardiovascular control, with a shift of regulation mechanisms from dominant cardiac to dominant vascular influences between the early and late response phases, respectively. This study investigated whether similar rearrangement occurs during life stress accompanying chronic disease by analyzing also associations between cortisol level and cardiovascular variables in patients with fibromyalgia (FM). In 47 women with FM and 36 healthy women (HW), cardiovascular recordings were taken during active body posture changes (sitting, lying down, and standing). Moreover, hair cortisol concentration (HCC) was obtained. During standing, which involved orthostatic challenge, FM patients showed higher total peripheral resistance (TPR) but lower stroke volume (SV), cardiac output (CO), and baroreflex sensitivity than HW. During sitting and lying down, TPR was more closely associated with blood pressure (BP) than CO in FM patients; in contrast, CO was more closely associated with BP than TPR in HW. HCC correlated positively with TPR and BP in FM patients, but negatively with TPR and BP and positively with SV and CO in HW. Results suggest that chronic disease‐related stress is associated with alterations in cardiovascular regulation toward greater involvement of vascular than cardiac mechanisms in BP control. Stress‐related cortisol release may contribute to the long‐term rearrangement of autonomic regulation. At the behavioral level, the dominance of vascular over cardiovascular control may relate to reduced somatic mobilization during an active fight‐flight response in favor of passive and behaviorally immobile coping. [ABSTRACT FROM AUTHOR]

BACKGROUND: PEEP is a cornerstone treatment for children with pediatric ARDS. Unfortunately, its titration is often performed solely by evaluating oxygen saturation, which can lead to inadequate PEEP level settings and consequent adverse effects. This study aimed to assess the impact of increasing PEEP on hemodynamics, respiratory system mechanics, and oxygenation in children with ARDS. METHODS: Children receiving mechanical ventilation and on pressure-controlled volume-guaranteed mode were prospectively assessed for inclusion. PEEP was sequentially changed to 5, 12, 10, 8 cm H2O, and again to 5 cm H2O. After 10 min at each PEEP level, hemodynamic, ventilatory, and oxygenation variables were collected. RESULTS: A total of 31 subjects were included, with median age and weight of 6 months and 6.3 kg, respectively. The main reasons for pediatric ICU admission were respiratory failure caused by acute viral bronchiolitis (45%) and community-acquired pneumonia (32%). Most subjects had mild or moderate ARDS (45% and 42%, respectively), with a median (interquartile range) oxygenation index of 8.4 (5.8-12.7). Oxygen saturation improved significantly when PEEP was increased. However, although no significant changes in blood pressure were observed, the median cardiac index at PEEP of 12 cm H2O was significantly lower than that observed at any other PEEP level (P = .001). Fourteen participants (45%) experienced a reduction in cardiac index of > 10% when PEEP was increased to 12 cm H2O. Also, the estimated oxygen delivery was significantly lower, at 12 cm H2O PEEP. Finally, respiratory system compliance significantly reduced when PEEP was increased. At a PEEP of 12 cm H2O, static compliance had a median reduction of 25% in relation to the initial assessment (PEEP of 5 cm H2O). CONCLUSIONS: Although it may improve arterial oxygen saturation, inappropriately high PEEP levels may reduce cardiac output, oxygen delivery, and respiratory system compliance in pediatric subjects with ARDS with low potential for lung recruitability. [ABSTRACT FROM AUTHOR]

The article explains the importance of assessing cardiac output for optimal vessel opacification in computed tomography for proper diagnoses. Topics discussed include different classifications of heart failure based on the sidedness and pumping abilities of the heart, determinants of cardiac output such as heartbeat, heart rate, preload, contractility and afterload, as well as Laplace's law of physiological wall stress and its effects on cardiac output.

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BACKGROUND The incidence of cardiovascular complications may be higher in unilateral than bilateral primary aldosteronism (PA). We compared noninvasive hemodynamics after targeted therapy of bilateral vs. unilateral PA. METHODS Adrenal vein sampling was performed, and hemodynamics recorded using radial artery pulse wave analysis and whole-body impedance cardiography (n  = 114). In 40 patients (adrenalectomy n  = 20, spironolactone-based treatment n  = 20), hemodynamic recordings were performed after 33 months of PA treatment. RESULTS In initial cross-sectional analysis, 51 patients had bilateral and 63 unilateral PA. The mean ages were 50.6 and 54.3 years (P  = 0.081), and body mass indexes 30.3 and 30.6 kg/m2 (P  = 0.724), respectively. Aortic blood pressure (BP) and cardiac output did not differ between the groups, but left cardiac work was ~10% higher in unilateral PA (P  = 0.022). In the follow-up study, initial and final BPs in the aorta were not significantly different, while initial cardiac output (+13%, P  = 0.015) and left cardiac work (+17%, P  = 0.009) were higher in unilateral than bilateral PA. After median treatment of 33 months, the differences in cardiac load were abolished, and extracellular water volume was reduced by 1.3 and 1.4 l in bilateral vs. unilateral PA, respectively (P  = 0.814). CONCLUSIONS These results suggest that unilateral PA burdens the heart more than bilateral PA, providing a possible explanation for the higher incidence of cardiac complications in unilateral disease. A similar reduction in aldosterone-induced volume excess was obtained with targeted surgical and medical treatment of PA. [ABSTRACT FROM AUTHOR]

The classification of cardiogenic shock (CS) has evolved from a singular cold-and wet-hemodynamic profile. Data from registries and clinical trials have contributed to a broader recognition that although all patients with CS have insufficient cardiac output leading to end organ hypoperfusion, there is considerable variability in CS acuity, underlying etiologies, volume status, and systemic vascular resistance. Mixed CS can be broadly categorized as CS with at least 1 additional shock state. Mixed CS states are now the second leading cause of shock in contemporary coronary intensive care units, but there is little high-quality evidence to guide routine care, and there are no standardized classification frameworks or well-established hemodynamic definitions. This primer summarizes the current epidemiology and proposes a classification framework and invasive hemodynamic parameters to guide categorization that could be applied to help better phenotype patients captured in registries and trials, as well as guide management of mixed CS states. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusion This study evaluated the hemodynamic performance of arterial and venous cannulae in a compliant pediatric extracorporeal membrane oxygenation (ECMO) mock circuit in pulsatile and non‐pulsatile flow conditions.The ECMO setup consisted of an oxygenator, diagonal pump, and standardized‐length arterial/venous tubing with pressure transducers. A validated left‐heart mock loop was adapted to simulate pediatric conditions. The pulsatile flow was driven by a computer‐controlled piston pump set at 120 bpm. A roller pump was used for non‐pulsatile conditions. The circuit was primed with 40% glycerol‐based solution. The cardiac output was set to 1 L/min and the aortic pressure to 40–50 mmHg. Four arterial cannulae (8Fr, 10Fr, 12Fr, 14Fr) and five venous cannulae (12Fr, 14Fr, 16Fr, 18Fr, 20Fr) (Medtronic, Inc., Minneapolis, MN, USA) were tested at increasing flow rate in 12 combinations.The pulsatile condition required lower ECMO pump speeds for all cannulae combinations at a given flow rate, inducing a significantly smaller increase of flow in the mock loop. Under non‐pulsatile conditions, the aortic and arterial pressures in the cannulae were higher (p < 0.01) while no significant differences in pressure drop and pressure‐flow characteristics (M‐number) were observed. The total hemodynamic energy was higher in case of non‐pulsatile flow (p < 0.01).Under non‐pulsatile conditions, the system was characterized by overall higher pressures, resulting in higher support to the patient. The consequent increase of potential energy compensates for increases of kinetic energy, leading to a higher total hemodynamic energy. Pressure gradients and M number are independent of the testing conditions. Pulsatile testing conditions led to more physiological testing conditions, and it is recommended for ECMO testing. [ABSTRACT FROM AUTHOR]

Background: Despite being essential in patients with acute respiratory distress syndrome (ARDS), mechanical ventilation (MV) may cause lung injury and hemodynamic instability. Mechanical power (MP) may describe the net injurious effects of MV, but whether it reflects the hemodynamic effects of MV is currently unclear. We hypothesized that MP is also associated with cardiac output (CO) and pulmonary blood flow (PBF). Methods: 24 anesthetized pigs with experimental acute lung injury were ventilated for 18 h according to one of three strategies: 1) Open lung approach (OLA), 2) ARDS Network high-PEEP/FIO2 strategy (HighPEEP), or 3) low-PEEP/FIO2 strategy (LowPEEP). Total MP was assessed as the sum of energy dissipated to overcome airway resistance and energy temporarily stored in the elastic lung tissue per minute. The distribution of pulmonary perfusion was determined by positron emission tomography. Regional PBF and MP, assessed in three iso-gravitational regions of interest (ROI) with equal lung mass (ventral, middle, and dorsal ROI), were compared between groups. Results: MP was higher in the LowPEEP than in the OLA group, while CO did not differ between groups. After 18 h, regional PBF did not differ between groups. During LowPEEP, regional MP was higher in the ventral ROI compared to OLA and HighPEEP groups (2. 5 ± 0. 3 vs. 1. 4 ± 0. 4 and 1. 6 ± 0. 3 J/min, respectively, P < 0. 001 each), and higher in the middle ROI compared to the OLA group (2. 5 ± 0. 4 vs. 1. 6 ± 0. 5 J/min, P = 0. 04). MP in the dorsal ROI did not differ between groups (1. 4 ± 0. 9 vs. 1. 4 ± 0. 5 vs. 1. 3 ± 0. 8 J/min, P = 0. 916). Total MP was independently associated with CO [0. 34 (0. 09, 0. 59), P = 0. 020]. Regional MP was positively associated with PBF irrespective of the regions [0. 52 (0. 14, 0. 76), P = 0. 01; 0. 49 (0. 10, 0. 74), P = 0. 016; 0. 64 (0. 32, 0. 83), P = 0. 001 for ventral, middle, and dorsal ROI, respectively]. Subgroup analysis revealed a significant association of MP and CO only in the OLA group as well as a significant association between MP with regional PBF only in the HighPEEP group. Conclusion: In this model of acute lung injury in pigs ventilated with either open lung approach, high, or low PEEP tables recommended by the ARDS network, MP correlated positively with CO and regional PBF, whereby these clinically relevant lung-protective ventilation strategies influenced the associations. [ABSTRACT FROM AUTHOR]

Fetal teratomas, though rare, represent a significant proportion of tumors arising during fetal development. These tumors arise from pluripotent cells and can present in varying degrees of severity, ranging from incidental findings to life-threatening conditions. Prenatal imaging, via ultrasound and MRI, is necessary for diagnosis and risk assessment. The management of fetal teratomas, particularly those associated with complications like hydrops or airway obstruction, often requires a multidisciplinary approach. Interventions such as ex-utero intrapartum treatment (EXIT) procedures and minimally invasive alternatives have emerged as critical tools to improve neonatal outcomes in severe cases. Despite advances in fetal therapies, careful prenatal monitoring and individualized management remain essential, especially for tumors with high vascularity or those that risk compromising cardiac output. This review explores the diagnostic methods, management strategies, and outcomes associated with fetal teratomas, highlighting recent advancements that contribute to improving survival and reducing morbidity in affected neonates. [ABSTRACT FROM AUTHOR]

Younger women rely on altering cardiac output (Q̇$\dot{Q}$) to regulate blood pressure (BP). In contrast, older women rely more on altering vascular tone. However, evidence suggests that the ability to alter systemic vascular conductance (SVC) is diminished in older women. In the present study, cardioselective β‐blockade was utilized to diminish the relative contribution of Q̇$\dot{Q}$ to BP regulation and thereby evaluate age‐related vascular limitations in women at rest and during large muscle dynamic exercise. Younger (n = 13, mean age 26.0 years) and older (n = 14, mean age 61.8 years) healthy women performed submaximal bouts of semi‐recumbent cycling exercise at varying intensities while receiving an intravenous infusion of esmolol, a β1‐antagonist, or saline control in a repeated‐measures crossover design. Q̇$\dot{Q}$ was attenuated during esmolol infusion, with greater reductions during exercise (moderate, –1.0 (95% CI, –1.6 to –0.5) L/min, P < 0.001; heavy, –2.0 (95% CI, –2.6 to –1.5) L/min, P < 0.001) than seated rest (–0.5 (95% CI, –1.1 to 0.0) L/min, P = 0.048), and this reduction was not significantly different between age groups (P = 0.122). Older women exhibited a greater attenuation in mean arterial pressure (MAP) during esmolol (–7 (95% CI, –9 to –4) mmHg, P < 0.001) relative to younger women (–2 (95% CI, –5 to 0) mmHg, P = 0.071). These changes coincided with a greater reduction of SVC in the younger women during esmolol (–15 (95% CI, –20 to –10) mL/min/mmHg, P < 0.001) compared to older women (–3 (95% CI, –9 to 2) mL/min/mmHg, P = 0.242). Together, these findings provide evidence that older, postmenopausal women have a diminished ability to adjust SVC in order to regulate MAP. [ABSTRACT FROM AUTHOR]

The article focuses on a clinical case of a 50-day-old male with tricuspid atresia and restrictive interatrial defect. The patient had compromised cardiac output and timely interventions were performed to address his complex heart condition. The importance of prenatal diagnosis of complex heart conditions is highlighted to improve patient survival, as well as short-term follow-up by a multidisciplinary group of experts. [Extracted from the article]

Climate change is the greatest threat to global health. As climate change worsens, heat waves will be longer, more intense, and more frequent. Increased health risks from climate change and heat waves include heat-related illness (HRI). HRI increases ED visits, hospitalizations, and mortality. Healthcare providers should be aware of the impact of medications on risk for HRI. This article elucidates signs and symptoms, populations at risk, drugs and mechanisms that increase risk, and patient education to reduce risk. [ABSTRACT FROM AUTHOR]

Peripheral venoarterial extracorporeal membrane oxygenation (VA-ECMO) is an advanced temporary life support system for patients with refractory cardiogenic shock or severe cardiopulmonary failure. However, the reperfusion of oxygenated blood into the arterial system via a peripheral artery will induce substantial hemodynamic changes that might contribute to the development of complications. In this study, we developed two types of computational models to quantify the hemodynamic changes induced by the peripheral VA-ECMO support for systolic heart failure (HF) of various severities. One was a lumped-parameter model used for exploring the optimal workload of extracorporeal membrane oxygenation (ECMO) for a specific severity of HF, whereas the other one was a geometrical multiscale model capable of simulating the detailed flow field in the aorta while accounting for the hemodynamic coupling of VA-ECMO with the cardiovascular system. Numerical results revealed that the retrograde transmission of ECMO-supplied blood flow toward the heart not only considerably inhibited cardiac output but also induced marked flow disturbance and regionally high or oscillatory wall shear stress (WSS) in the aorta that may increase the risk of thrombosis and vascular dysfunction. The major characteristics of flow disturbance and spatial distribution of abnormal WSS were codetermined by the cardiac function and workload of ECMO while less influenced by the morphology of aorta. These findings emphasized the importance of tuning the workload of ECMO based on patient-specific cardiac function to balance the amount of blood oxygenation support by ECMO against the risk of complications associated with hemodynamic abnormalities. [ABSTRACT FROM AUTHOR]

Background: Patients with chronic kidney disease (CKD) possess a pronounced risk for cardiovascular events. A noninvasive left ventricular pressure‐strain loop (LV‐PSL) has recently been introduced to detect subtler changes in cardiac function. This study aims to investigate the value of LV‐PSL for quantitative assessment of myocardial work (MW) in patients with CKD. Methods: Seventy‐five patients with CKD were enrolled retrospectively (37 patients with CKD Stages 2–3, and 38 patients with CKD Stages 4–5), and 35 healthy volunteers were included as controls. All subjects underwent transthoracic echocardiography. LV‐PSL analysis was performed to estimate LV MW and efficiency. Global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were obtained by echocardiography, and the differences among the groups were compared. Results: There was a significant increase in GWW and reduction in GWE in patients with CKD compared to normal controls (p < 0.05). No significant difference in GWI and GCW was observed among the three groups. Multiple linear regression revealed that increased GWW was significantly associated with age, serum creatinine, and systolic pressure, and decreased GWE was associated with age, serum creatinine, and GLS. Conclusion: LV‐PSL can be used for noninvasive quantitative assessment of MW in patients with CKD, providing a new sensitive approach for the clinical assessment of myocardial function. [ABSTRACT FROM AUTHOR]

Competitive swimmers complete 50‐m front crawl swimming without breathing or with a limited number of breaths. Breath holding during exercise can trigger diving reflex including bradycardia and diminished active muscle blood flow, whereas oxygen supply to vital organ such as brain is maintained. We hypothesized that swimmers achieving faster time in 50‐m front crawl with limited number of breaths demonstrate a blunted diving reflex of cardiac and active muscle blood flow responses with elevated cerebral perfusion to counteract peripheral and central fatigues. Twenty‐eight competitive swimmers (12 females) underwent a 50‐m front crawl swimming time trial with minimum respiratory interruptions, following which they were categorized into two groups: Fast (n = 13) and Slow (n = 15). Additionally, they performed knee extension exercises with maximal voluntary breath‐ holding, wherein leg blood flow (Doppler ultrasound), cardiac output (Modelflow), heart rate (electrocardiogram), and middle cerebral artery mean blood velocity (transcranial Doppler ultrasound) were evaluated. The pattern of leg blood flow response differed between the two groups (p = 0.031) with the Fast group experiencing a delayed onset of reductions in leg blood flow (p = 0.035). The onset of bradycardia was also delayed in the Fast group (p = 0.014), with this group demonstrating a higher value of the lowest heart rate (between‐trial difference in average: 15.9 [3.73, 28.2] beats/min) and cardiac output (between‐trial difference in median: 2.84 L/min) (both, p ≤ 0.013). Middle cerebral artery mean blood velocity was similar between the groups (all p ≥ 0.112). We show that swimmers with superior performance in 50‐m front crawl swim with limited breaths display a diminished diving reflex. [ABSTRACT FROM AUTHOR]

Background: Heartbeat abnormalities, such as when it beats too quickly or too slowly, are known as cardiac arrhythmias. Although certain arrhythmias are more common in neonates and young infants compared to older children and adults, all types of arrhythmias can occur. Many are benign and do not cause hemodynamic compromise. Others may compromise cardiac output and cause decreased blood pressure and decreased perfusion. Arrythmias can be due to abnormal structure of the heart, cardiomyopathy, inherited diseases, drugs, infections, inflammation, systemic diseases, autoimmune diseases, mechanical ventilation, central venous line insertion, electrolyte disturbance and others. Not all arrhythmias provide the same risk to the patient, despite the fact that they are frequently seen in critically ill patients. Certain arrhythmias, for instance, can be benign and selflimiting, whereas others might swiftly worsen and become potentially fatal. Aim:An overview of the most frequent causes of arrhythmias in children with acquired or structurally congenital cardiac disorders is provided in this article. Conclusion: In pediatric patients there are wide range of causes for arrhythmias. May be caused by primarily diseases or acquired factors. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the utility of Pulse index Contour Continuous Cardiac Output (PiCCO) monitoring in critically ill patients. Study Design: Cross-sectional study. Setting: Intensive Care Unti of Sindh Institute of Urology and Transplant, Karachi, Pakistan. Period: October 2022 to March 2023. Methods: Patients presenting with various types of shock, requiring high-dose vasopressors or inotropes, and not responding to initial fluid therapy were analyzed. Demographic details, SOFA score, APACHE score, and invasive hemodynamic parameters using the PiCCO system were documented. Results: Out of 142 ICU admissions, 38 patients were included in the study. Most patients were males (73%) with a median age of 39 years. Significant changes were observed in the cardiac index, cardiac performance index, global ejection fraction, and systemic vascular resistance index (SVRI), all with p-values less than 0.05. The interventions included the initiation of inotropes in 22 patients (57.8%), diuretics in 4 patients (10.5%), and intravenous fluids in 19 patients (50%). Additionally, vasopressor doses were adjusted in 18 patients (47.3%). Initially, patients were presumed to have pure septic shock based on CO2 gap, mixed venous saturation, and echocardiographic assessment. However, after applying PiCCO monitoring, the diagnosis was revised to mixed shock in 21 patients (55.2%). Conclusion: PiCCO monitoring appears to be a valuable tool in the ICU for managing patients with complex hemodynamic profiles, facilitating targeted interventions that lead to significant improvements in hemodynamic stability. [ABSTRACT FROM AUTHOR]

The present cross-sectional study aimed to compare climacteric symptoms and arterial stiffness indices between perimenopausal and postmenopausal women. The study sample comprised 70 healthy female participants, including 27 perimenopausal (49.8 ± 3.8 years) and 43 postmenopausal (55.7 ± 4 years) individuals. Validated methods were used to assess physical activity level, quality of life, climacteric symptoms, and anthropometric data. Arterial stiffness parameters were measured using Mobil-O-Graph. Pulse wave velocity (PWV) had a higher mean in the postmenopausal group than in the perimenopause group [8.04 m/s (SD 0.79) vs 7.01 m/s (SD 0.78), p <.001). PWV was strongly correlated with peripheral (r = 0.619) and central (r = 0.632) Systolic Blood Pressure (SBP) in postmenopausal group and an even stronger correlation was observed in perimenopausal group (r = 0.779 pSBP and 0.782 cSBP). BMI was a risk predictor in the perimenopausal group contributing positively to increase Pulse Pressure Amplification (PPA) (0.458, p <.05). In postmenopausal women, heart rate (HR) was a stronger predictor for central SBP, cardiac output, and total vascular resistance, whereas perimenopausal women HR influenced central diastolic blood pressure and PPA. Vascular changes initiating during perimenopause may contribute to the development of cardiovascular pathologies in the postmenopausal period. Further research with larger, representative samples is warranted to corroborate these findings. [ABSTRACT FROM AUTHOR]

Purpose: The involvement of central command in central hemodynamic regulation during exercise is relatively well-known, although its contribution to peripheral hemodynamics at the onset of low-intensity contractions is debated. This study sought to examine central and peripheral hemodynamics during electrically-evoked muscle contractions (without central command) and voluntary muscle activity (with central command). Methods: Cyclic quadriceps isometric contractions (1 every second), either electrically-evoked (ES; 200 ms trains composed of 20 square waves) or performed voluntarily (VC), were executed by 10 healthy males (26 ± 3 years). In both trials, matched for force output, peripheral and central hemodynamics were analysed. Results: At exercise onset, both ES and VC exhibited equal peaks of femoral blood flow (1276 ± 849 vs. 1117 ± 632 ml/min, p > 0.05) and vascular conductance (15 ± 11 vs. 13 ± 7 ml/min/mmHg, p > 0.05), respectively. Similar peaks of heart rate (86 ± 16 bpm vs. 85 ± 16 bpm), stroke volume (100 ± 20 vs. 99 ± 27 ml), cardiac output (8.2 ± 2.5 vs. 8.5 ± 2.1 L/min), and mean arterial pressure (113 ± 13 vs. 113 ± 3 mmHg), were recorded (all, p > 0.05). After ~ 50 s, all the variables drifted to lower values. Collectively, the hemodynamics showed equal responses. Conclusion: These results suggest a similar pathway for the initial (first 40 s) increase in central and peripheral hemodynamics. The parallel responses may suggest an initial minimal central command involvement during the onset of low-intensity contractions, likely associated with a neural drive activation delay or threshold. [ABSTRACT FROM AUTHOR]

Cardiovascular disease is the leading indirect cause of maternal morbidity and mortality, accounting for nearly one third of maternal deaths during pregnancy. The burden of cardiovascular disease in pregnancy is increasing, as are the incidence of maternal morbidity and mortality. Normal physiologic adaptations to pregnancy, including increased cardiac output and plasma volume, may unmask cardiac conditions, exacerbate previously existing conditions, or create de novo complications. It is important for care providers to understand the normal physiologic changes of pregnancy and how they may impact the care of patients with cardiovascular disease. This review outlines the physiologic adaptions during pregnancy and their pathologic implications for some of the more common cardiovascular conditions in pregnancy. [ABSTRACT FROM AUTHOR]

We recently explored the cardiopulmonary interactions during partial unloading of the respiratory muscles during exercise. Expanding upon this work, we present a noteworthy case study whereby we eliminated the influence of respiration on cardiac function in a conscious but mechanically ventilated human during exercise. This human was a young healthy endurance-trained male who was mechanically ventilated during semi-recumbent cycle exercise at 75 Watts (W) (∼30% Wmax). During mechanically ventilated exercise, esophageal pressure was reduced to levels indistinguishable from the cardiac artefact which led to a 94% reduction in the power of breathing. The reduction in respiratory pressures and respiratory muscle work led to a decrease in cardiac output (−6%), which was due to a reduction in stroke volume (−13%), left ventricular end-diastolic volume (−15%), and left-ventricular end-systolic volume (−17%) that was not compensated for by heart rate. Our case highlights the influence of extreme mechanical ventilation on cardiac function while noting the possible presence of a maximal physiological limit to which respiration (and its associated pressures) impacts cardiac function when the power of breathing is maximally reduced. [ABSTRACT FROM AUTHOR]

OBJECTIVE To establish an echocardiographic technique in koi carp (Cyprinus carpio), compare cardiopulmonary parameters under manual restraint versus anesthesia, and provide a gross anatomical and histologic cardiac description. METHODS A randomized, crossover echocardiography study was performed in 40 clinically healthy adult, unknown sex, privately owned koi carp on May 10 and 11 through June 26 and 27, 2021. Echocardiography was examined for each koi under manual restraint and isoeugenol at 50 ppm, with 3 measurements per examination performed by a radiologist and cardiologist. Two koi were euthanized for gross anatomic and histologic cardiac evaluation. RESULTS Mean ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were significantly lower, mean heart rate (HR) was significantly higher, and opercular rate (OPR) was decreased significantly in anesthetized compared to manually restrained koi. Poor reproducibility for EF and SV was observed. CONCLUSIONS Echocardiography was feasible in both manually restrained and anesthetized koi; however, this technique may best be applied to monitoring trends over time in individual fish due to low reproducibility. Significant differences in multiple cardiopulmonary parameters, including HR, EF, SV, CO, and OPR, were present between manually restrained and anesthetized koi. A gross anatomic and histologic cardiac description is provided for this species to pair with the echocardiographic images. CLINICAL RELEVANCE This study provides the first description of echocardiography, cardiac gross anatomy, and histology in koi. The results support echocardiography as a safe and practical noninvasive diagnostic for cardiac assessment in koi under both manual restraint and anesthesia. [ABSTRACT FROM AUTHOR]

OBJECTIVE To investigate whether liver compression (LC) could increase stroke volume (SV) by more than 15% in healthy, anesthetized dogs with hypovolemia and suggest LC as a novel method to evaluate fluid responsiveness. ANIMALS 6 healthy Beagles. METHODS This prospective, nonrandomized experimental study was conducted from November 2023 to February 2024. The dogs were anesthetized with isoflurane and mechanically ventilated under neuromuscular blockade. After instrumentation, the dogs underwent the following 4 experimental stages in a sequential, nonrandomized manner: stage 1, baseline; stage 2, 30% withdrawal of circulating blood volume; stage 3, 50% infusion of the collected blood; and stage 4, the remaining 50% infusion of the collected blood. At each stage, SV via pulmonary artery thermodilution and hemodynamic variables were measured before, during, and after the LC. RESULTS In stage 2, LC significantly increased mean SV by 30%, from 6.9 to 9 mL/beat. Simultaneously, LC significantly increased mean arterial pressure by 11 mm Hg and mean central venous pressure by 2 mm Hg, while pulse pressure variation significantly decreased from 28% to 22%. In stages 1, 3, and 4, LC did not significantly change mean SV, mean arterial pressure, and pulse pressure variation; however, mean central venous pressure significantly increased during stage 3. CLINICAL RELEVANCE This study demonstrates that LC at 22 mm Hg for 1 minute could increase SV more than 15% in anesthetized, hypovolemic dogs and LC could be used as a novel method to evaluate fluid responsiveness. [ABSTRACT FROM AUTHOR]

Objective: To compare maternal vascular indices and hemodynamic parameters at 35–37 weeks' gestation in pregnancies complicated by delivery of a small‐for‐gestational‐age (SGA) or growth‐restricted (FGR) neonate. Methods: This was a prospective observational study of women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. The visit included recording of maternal demographic characteristics, medical history, vascular indices and hemodynamic parameters, which were obtained using a non‐invasive operator‐independent device and included pulse‐wave velocity, augmentation index, cardiac output, stroke volume, central systolic and diastolic blood pressure, total peripheral resistance and heart rate. Women with hypertensive disorders of pregnancy were excluded. SGA was diagnosed if birth weight was < 10th percentile. FGR was diagnosed if, in addition to birth weight < 10th percentile, at the 35–37‐week scan, uterine artery or umbilical artery pulsatility index (PI) was > 95th percentile or fetal middle cerebral artery PI was < 5th percentile. Results: Among the 6413 women included in the study, there were 605 (9.4%) cases of SGA, 133 (2.1%) cases of FGR and 5675 (88.5%) cases that were unaffected by SGA or FGR. Women with SGA or FGR, compared to unaffected pregnancies, had increased peripheral vascular resistance and reduced cardiac output. Central systolic and diastolic blood pressure were increased in the FGR group compared with the unaffected group. Aortic stiffness, as assessed by pulse‐wave velocity, and augmentation index did not differ between affected and unaffected pregnancies. In the FGR group, compared with the SGA group, central systolic and diastolic blood pressure were higher, whereas heart rate was lower. Conclusions: SGA and FGR pregnancies exhibit deranged maternal hemodynamic responses compared with unaffected pregnancies. Pregnancies with FGR have higher central blood pressure compared to those with SGA, but it remains unclear whether these differences are driven by the size of the fetus or pathological fetal growth. © 2024 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

During pregnancy an increased cardiac output (Q̇$\dot{Q}$) and blood volume (BV) occur to support fetal growth. Increased Q̇$\dot{Q}$ and BV also occur during chronic endurance exercise training and benefit performance. We investigated if sprint interval training (SIT) undertaken early postpartum maintains the elevated Q̇$\dot{Q}$ and BV of pregnancy and benefits performance. The participant, a competitive field hockey player and former cyclist, visited our laboratory at 2 weeks of gestation (baseline) and postpartum pre‐, mid‐ and post‐intervention (PPpre, PPmid and PPpost). Delivery was uncomplicated and she felt ready to start the SIT programme 5 weeks postpartum. Inert gas rebreathing was used to measure peak exercise Q̇$\dot{Q}$ (Q̇$\dot{Q}$peak); V̇O2peak${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ was measured with a metabolic cart; and postpartum haematological values were measured with carbon monoxide rebreathing. The 18 SIT sessions progressed from four to eight sprints at 130% of V̇O2peak${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ peak power output. Q̇$\dot{Q}$peak increased from baseline at all postpartum time points (baseline 16.2 vs. 17.5, 16.8 and 17.2 L/min at PPpre, PPmid and PPpost, respectively). Relative V̇O2peak${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ remained below baseline values at all postpartum measurements (baseline 44.9 vs. 41.0, 42.3 and 42.5 mL/kg/min at PPpre, PPmid and PPpost, respectively) whereas absolute V̇O2peak${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ rapidly reached baseline values postpartum (baseline 3.19 vs. 3.12, 3.23 and 3.18 L/min at PPpre, PPmid and PPpost, respectively). Postpartum BV (5257, 4271 and 5214 mL at PPpre, PPmid and PPpost, respectively) and Hbmass (654, 525 and 641 g at PPpre, PPmid and PPpost, respectively) were similar between PPpre and PPpost but decreased alongside Q̇$\dot{Q}$peak at PPmid. Peak power was returned to pre‐pregnancy values by intervention end (302 vs. 303 W, baseline vs. PPpost). These findings show that SIT undertaken early postpartum defends the elevated Q̇$\dot{Q}$peak of pregnancy and rapidly returns absolute V̇O2peak${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ and peak power to baseline levels. What is the central question of this study?Can the enhanced cardiac output of pregnancy be maintained with strenous exercise training undertaken early postpartum.What is the main finding and its importance?Baseline values of absolute oxygen consumption, peak power output and peak exercise cardiac output can be regained rapidly or surpassed following 6 weeks of sprint interval training postpartum. Sprint interval training can be used by endurance trained females to safely resume training early postpartum, allowing a rapid and efficient return to baseline fitness levels. [ABSTRACT FROM AUTHOR]

Purpose: This study was performed to evaluate the changes in oxygen supply–demand balance during induction of general anesthesia using an indirect calorimeter capable of measuring oxygen consumption (VO2) and carbon dioxide production (VCO2). Methods: This study included patients scheduled for surgery in whom remimazolam was administered as a general anesthetic. VO2 and VCO2 were measured at different intervals: upon awakening (T1), 15 min after tracheal intubation (T2), and 1 h after T2 (T3). Oxygen delivery (DO2) was calculated simultaneously with these measurements. VO2 was ascertained using an indirect calorimeter and further calculated using vital signs, among other factors. DO2 was derived from cardiac output and arterial blood gas analysis performed with an arterial pressure-based cardiac output measurement system. Results: VO2, VCO2, and DO2 decreased significantly from T1 to T2 and T3 [VO2/body surface area (BSA) (ml/min/m2): T1, 130 (122–146); T2, 107 (83–139); T3, 97 (93–121); p = 0.011], [VCO2/BSA (ml/min/m2): T1, 115 (105–129); T2, 90 (71–107); T3, 81 (69–101); p = 0.011], [DO2/BSA (ml/min/m2): T1, 467 (395–582); T2, 347 (286–392); T3, 382 (238–414); p = 0.0020]. Among the study subjects, a subset exhibited minimal reduction in VCO2. Although the respiratory frequency was titrated on the basis of end-tidal CO2 levels, there was no significant difference between the groups. Conclusion: General anesthetic induction with remimazolam decreased VO2, VCO2, and DO2. [ABSTRACT FROM AUTHOR]

When calculating cardiac index (C.I.) by the Fick method, oxygen consumption (VO2) is often unknown, so assumed values are typically used. This practice introduces a known source of inaccuracy into the calculation. Using a measured VO2 (mVO2) from the CARESCAPE E-sCAiOVX module provides an alternative that may improve accuracy of C.I. calculations. Our aim is to validate this measurement in a general pediatric catheterization population and compare its accuracy with assumed VO2 (aVO2). mVO2 was recorded for all patients undergoing cardiac catheterization with general anesthesia and controlled ventilation during the study period. mVO2 was compared to the reference VO2 (refVO2) determined by the reverse Fick method using cardiac MRI (cMRI) or thermodilution (TD) as a reference standard for measurement of C.I. when available. 193 VO2 measurements were obtained, including 71 with a corresponding cMRI or TD measure of cardiac index for validation. mVO2 demonstrated satisfactory concordance and correlation with the TD- or cMRI-derived refVO2 (ρc = 0.73, r2 = 0.63) with a mean bias of − 3.2% (SD ± 17.3%). Assumed VO2 demonstrated much weaker concordance and correlation with refVO2 (ρc = 0.28, r2 = 0.31) with a mean bias of + 27.5% (SD ± 30.0%). Subgroup analysis of patients < 36 months of age demonstrated that error in mVO2 was not significantly different from that observed in older patients. Many previously reported prediction models for assuming VO2 performed poorly in this younger age range. Measured oxygen consumption using the E-sCAiOVX module is significantly more accurate than assumed VO2 when compared to TD- or cMRI-derived VO2 in a pediatric catheterization lab. [ABSTRACT FROM AUTHOR]

Some patients with chronic thromboembolic pulmonary hypertension (CTEPH) exhibit exercise intolerance due to reduced cardiac output (CO) even after successful balloon pulmonary angioplasty (BPA). Medical therapy is a potential option for such cases; however, it is unclear which patients necessitate it even after BPA. This study included 286 patients with CTEPH who underwent BPA and right heart catheterization 1 year after the final BPA and classified them into no-medication and withdrawal groups. The no-medication group comprised patients without pulmonary hypertension (PH) medications before and after BPA, while the withdrawal group included patients who received PH medications before BPA and discontinued them after BPA. We assessed differences in the changes in CO after BPA from baseline (ΔCO) between the 2 groups. Additionally, we evaluated the ΔCO among different age categories within each group: younger (<60 years), middle-aged (60-70 years), and older adults (≥70 years). After adjusting baseline covariates, overall CO did not differ significantly. However, ΔCO was significantly positive in the no-medication group but negative in the withdrawal group (0.32 and −0.33, difference in ΔCO: −0.65, 95% confidence intervals: −0.90 to −0.40). A significantly positive effect on ΔCO was observed in younger and middle-aged individuals, with a significant interaction between age and ΔCO in no-medication groups. Increasing CO with BPA alone may be challenging with age in patients with CTEPH. Given that discontinuation of PH medication after BPA decreased CO more than the effect of BPA, medical therapy might be necessary even after successful BPA. [ABSTRACT FROM AUTHOR]

Background: Traumatic brain injury (TBI) poses a significant challenge to healthcare providers, necessitating meticulous management of hemodynamic parameters to optimize patient outcomes. This article delves into the critical task of defining and meeting continuous arterial blood pressure (ABP) and cerebral perfusion pressure (CPP) targets in the context of severe TBI in neurocritical care settings. Methods: We narratively reviewed existing literature, clinical guidelines, and emerging technologies to propose a comprehensive approach that integrates real-time monitoring, individualized cerebral perfusion target setting, and dynamic interventions. Results: Our findings emphasize the need for personalized hemodynamic management, considering the heterogeneity of patients with TBI and the evolving nature of their condition. We describe the latest advancements in monitoring technologies, such as autoregulation-guided ABP/CPP treatment, which enable a more nuanced understanding of cerebral perfusion dynamics. By incorporating these tools into a proactive monitoring strategy, clinicians can tailor interventions to optimize ABP/CPP and mitigate secondary brain injury. Discussion: Challenges in this field include the lack of standardized protocols for interpreting multimodal neuromonitoring data, potential variability in clinical decision-making, understanding the role of cardiac output, and the need for specialized expertise and customized software to have individualized ABP/CPP targets regularly available. The patient outcome benefit of monitoring-guided ABP/CPP target definitions still needs to be proven in patients with TBI. Conclusions: We recommend that the TBI community take proactive steps to translate the potential benefits of personalized ABP/CPP targets, which have been implemented in certain centers, into a standardized and clinically validated reality through randomized controlled trials. [ABSTRACT FROM AUTHOR]

Mean arterial pressure (MAP) is a product of cardiac output (CO) and systemic vascular resistance. CO is calculated by multiplying stroke volume (SV) by heart rate. SV is determined by preload, cardiac contractility and afterload. These physiological parameters are targeted to manage blood pressure to maintain organ perfusion. In the hypotensive patient, assess fluid status and give intravenous (IV) crystalloid fluid resuscitation if appropriate. This optimizes the cardiac output, through an increase in end diastolic volume, based on the Frank–Starling law. If the patient's blood pressure is not fluid responsive, pharmacological intervention through inotropes, chronotropes and vasopressors may be required. A target MAP may be personalized based upon history and clinical examination. When the vasoactive intervention is escalating, cardiac monitoring may help guide further management. Mechanical circulatory support may be used in specialist centres. The hypertensive patient will be admitted to the intensive care unit (ICU) for invasive blood pressure monitoring and screening for end organ damage. Start by treating pain and anxiety. Regular oral antihypertensives may be continued if not contraindicated. IV antihypertensives in the form of beta blockers, calcium channel blockers and vasodilators may be started. Blood pressure is reduced in a controlled and rapid manner. [ABSTRACT FROM AUTHOR]

Aims: The initial bundle of cares strongly affects haemodynamics and outcomes in acute decompensated heart failure cardiogenic shock (ADHF‐CS). We sought to characterize whether 24 h haemodynamic profiling provides superior prognostic information as compared with admission assessment and which haemodynamic parameters best predict in‐hospital death. Methods and results: All patients with ADHF‐CS and with available admission and 24 h invasive haemodynamic assessment from two academic institutions were considered for this study. The primary endpoint was in‐hospital death. Regression analyses were run to identify relevant predictors of study outcome. We included 127 ADHF‐CS patients [65 (inter‐quartile range 52–72) years, 25.2% female]. Overall, in‐hospital mortality occurred in 26.8%. Non‐survivors were older, with greater CS severity. Among admission variables, age [odds ratio (OR) = 1.06; 95% confidence interval (CI): 1.02–1.11; Padj = 0.005] and CPIRAP (OR = 0.62 for 0.1 increment; 95% CI: 0.39–0.95; Padj = 0.034) were found significantly associated with in‐hospital death. Among 24 h haemodynamic univariate predictors of in‐hospital death, pulmonary elastance (PaE) was the strongest (area under the curve of 0.77; 95% CI: 0.68–0.86). PaE (OR = 5.98; 95% CI: 2.29–17.48; Padj < 0.001), pulmonary artery pulsatility index (PAPi, OR = 0.77; 95% CI: 0.62–0.92; Padj = 0.013) and age (OR = 1.06; 95% CI: 1.02–1.11; Padj = 0.010) were independently associated with in‐hospital death. Best cut‐off for PaE was 0.85 mmHg/mL and for PAPi was 2.95; cohort phenotyping based on these PaE and PAPi thresholds further increased in‐hospital death risk stratification; patients with 24 h high PaE and low PAPi exhibited the highest in‐hospital mortality (56.2%). Conclusions: Pulmonary artery elastance has been found to be the most powerful 24 h haemodynamic predictor of in‐hospital death in patients with ADHF‐CS. Age, 24 h PaE, and PAPi are independently associated with hospital mortality. PaE captures ventricular (RV) afterload mismatch and PAPi provides a metric of RV adaptation, thus their combination generates four distinct haemodynamic phenotypes, enhancing in‐hospital death risk stratification. [ABSTRACT FROM AUTHOR]