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Ventricular suction is a common adverse event in ventricular assist device (VAD) patients and can be due to multiple underlying causes. The aim of this study is to analyze the potential of different therapeutic interventions to mitigate suction events induced by different pathophysiological conditions. To do so, a suction module was embedded in a cardiovascular hybrid (hydraulic-computational) simulator reproducing the entire cardiovascular system. An HVAD system (Medtronic) was connected between a compliant ventricular apex and a simulated aorta. Starting from a patient profile with severe dilated cardiomyopathy, four different pathophysiological conditions leading to suction were simulated: hypovolemia (blood volume: -900 ml), right ventricular failure (contractility -70%), hypotension (systemic vascular resistance: 8.3 Wood Units), and tachycardia (heart rate:185 bpm). Different therapeutic interventions such as volume infusion, ventricular contractility increase, vasoconstriction, heart rate increase, and pump speed reduction were simulated. Their effects were compared in terms of general hemodynamics and suction mitigation. Each intervention elicited a different effect on the hemodynamics for every pathophysiological condition. Pump speed reduction mitigated suction but did not ameliorate the hemodynamics. Administering volume and inducing a systemic vasoconstriction were the most efficient interventions in both improving the hemodynamics and mitigating suction. When simulating volume infusion, the cardiac powers increased, respectively, by 38%, 25%, 42%, and 43% in the case of hypovolemia, right ventricular failure, hypotension, and tachycardia. Finally, a management algorithm is proposed to identify a therapeutic intervention suited for the underlying physiologic condition causing suction.

The amount of blood loss determined in orthognathic surgery differs greatly among studies. This can be attributed to the inhomogeneity in study cohorts analysed, but may also be a result of the varying methodologies used for blood loss determination. However, this has yet to be explored. Thus, the aim of this study was to investigate the extent to which the formula and time point used to measure blood loss affect the blood loss volume, determined in a homogeneous cohort undergoing bimaxillary surgery. Blood loss was calculated at 24 and 48 hours postoperatively using the haemoglobin balance method and the formula of Hurle et al. The estimated total blood volume was established based on the formulae of Nadler et al. and Choi et al. Differences in blood loss volume with respect to time point and formula were analysed and compared. Fifty-four patients were included in the final analysis. Statistically significant differences in blood loss were observed: a significant increase in the blood loss volume from 24 hours to 48 hours postoperatively was detected. When comparing the formulae used, blood loss differed significantly at 24 hours after surgery; however no such difference resulted at 48 hours postoperatively. These findings imply that the time point of measuring blood loss is highly relevant, whereas the formulae applied seem to have less of an impact on the blood loss volumes calculated.

Acute normovolemic hemodilution (ANH) is associated with low oxygen carrying capacity of blood and purposed to cause renal injury in perioperative setting. It is best accomplished in a perioperative setting by a colloid such as hydroxyl ethyl starch (HES) due its capacity to fill the vascular compartment and maintain colloidal pressure. However, alterations of intra renal microvascular perfusion, flow and its effects on renal function and damage during ANH has not been sufficiently clarified. Based on the extensive use of HES in the perioperative setting we tested the hypothesis that the use of HES during ANH is able to perfuse the kidney microcirculation adequately without causing renal dysfunction and injury in pigs. Hemodilution (n = 8) was performed by stepwise replacing blood with HES to hematocrit (Hct) levels of 20% (T1), 15% (T2), and 10% (T3). Seven control animals were investigated. Systemic and renal hemodynamics were monitored. Renal microcirculatory perfusion was visualized and quantified using contrast-enhanced ultrasound (CEUS) and laser speckle imaging (LSI). In addition, sublingual microcirculation was measured by handheld vital microscopy (HVM). Intrarenal mean transit time of ultrasound contrast agent (IRMTT-CEUS) was reduced in the renal cortex at Hct 10% in comparison to control at T3 (1.4 ± 0.6 vs. 2.2 ± 0.7 seconds, respectively, P

IntroductionIn patients with mitral annular disjunction (MAD), it can be difficult to assess the severity of mitral regurgitation (MR), as they present with a prolapsing volume (i.e. volume resulting from mitral valve prolapse, blood volume shift) rather than a regurgitant jet. The influence of the mitral prolapsing volume (MPV) on cardiac dimensions is unknown. We hypothesised that the severity of MR is underestimated in these patients. Our aim was to measure MPV and to investigate its influence on cardiac dimensions in patients with MAD.MethodsWe retrospectively included 131 consecutive patients with MAD from our institution’s echocardiographic database. Transthoracic echocardiography was used to assess MPV. Additionally, we established a control group of 617 consecutive patients with degenerative mitral valve disease and performed propensity score matching.ResultsMedian MPV in the MAD group was 12 ml. MPV was an independent predictor for left ventricular end-diastolic (LVEDD) and end-systolic diameter (LVESD) and left atrial volume (allp 15 ml), LVEDD (56 ± 6 mm vs 51 ± 6 mm,p p p = 0.04] were significantly increased compared to matched patients with degenerative mitral valve disease and similarly assessed severity of MR.ConclusionDue to a volume shift based on the MPV rather than an actual regurgitant jet, MR severity cannot be assessed adequately in MAD patients. Increased MPV induces ventricular and atrial enlargement. These findings warrant future studies to focus on MPV as an additional parameter for assessment of the severity of MR in MAD patients.

BACKGROUND: Circulating tumour cells (CTCs) can be used to monitor cancer longitudinally, but their use in non-small cell lung cancer (NSCLC) is limited due to low numbers in the peripheral blood. Through diagnostic leukapheresis (DLA) CTCs can be obtained from larger blood volumes.METHODS: Patients with all stages of NSCLC were selected. One total body blood volume was screened by DLA before and after treatment. Peripheral blood was drawn pre- and post DLA for CTC enumeration by CellSearch. CTCs were detected in the DLA product (volume equalling 2 × 108 leucocytes) and after leucocyte depletion (RosetteSep, 9 mL DLA product). Single-cell, whole-genome sequencing was performed on isolated CTCs.RESULTS: Fifty-six patients were included. Before treatment, CTCs were more often detected in DLA (32/55, 58%) than in the peripheral blood (pre-DLA: 18/55, 33%; post DLA: 13/55, 23%, both at p CONCLUSIONS: DLA detected nine times more CTCs than in the peripheral blood. The sustained presence of CTCs in DLA after treatment was associated with therapy failure and shortened PFS.TRIAL REGISTRATION: The study was approved by the Medical Ethical Committee (NL55754.042.15) and was registered in the Dutch trial register (NL5423).

Understanding the contribution of the autonomic nervous system to cerebral blood flow (CBF) control is challenging, and interpretations are unclear. The identification of calcium channels and adrenoreceptors within cerebral vessels has led to common misconceptions that the function of these receptors and actions mirror those of the peripheral vasculature. This review outlines the fundamental differences and complex actions of cerebral autonomic activation compared to the peripheral circulation. Anatomical differences, including the closed nature of the cerebrovasculature, and differential adrenoreceptor subtypes, density, distribution and sensitivity, provide evidence that measures on peripheral sympathetic nerve activity cannot be extrapolated to the cerebrovasculature. Cerebral sympathetic nerve activity seems to act opposingly to the peripheral circulation, mediated at least in part by changes in intracranial pressure and cerebral blood volume. Additionally, heterogeneity in cerebral adrenoreceptor distribution highlights regional-specific autonomic regulation of CBF. Compensatory chemo- and autoregulatory responses throughout the cerebral circulation, and interactions with parasympathetic nerve activity are unique features to the cerebral circulation. This crosstalk between sympathetic and parasympathetic reflexes acts to ensure adequate perfusion of CBF to rising and falling perfusion pressures, optimising delivery of oxygen and nutrients to the brain, whilst attempting to maintain blood volume and intracranial pressure. Herein, we highlight the distinct similarities and differences between autonomic control of cerebral and peripheral blood flow, and the regional specificity of sympathetic and parasympathetic regulation within the cerebrovasculature. Future research directions are outlined with the goal to further our understanding of autonomic control of CBF in humans. This article is protected by copyright. All rights reserved.

AIM Despite improvement in preterm survival, neurological morbidity remains high. 3D fractional moving blood volume (3D-FMBV) quantifies neonatal cerebral perfusion by calculating a standardised measure of the amount of moving blood in a region of interest and correlates with tissue perfusion in animal studies. However, its feasibility and reproducibility are yet to be assessed in newborn infants. METHODS Fractional moving blood volume analysis was performed on three-dimensional power Doppler ultrasound (PD-US) volumes from a cohort of preterm infants recruited in 2015 from the Royal Hospital for Women Neonatal Intensive Care Unit. The volumes were acquired by two sonographers and analysed by two different observers. The 3D-FMBV algorithm was applied to calculate an estimate for perfusion. Reproducibility and agreement were assessed using intra-class correlation coefficients (ICC) and Bland-Altman plots. RESULTS All 3D PD-US volumes were analysed successfully. Intra-observer reliability was excellent with an ICC of 0.907 (95% CI 0.751-0.968) and 0.906 (95% CI 0.741-0.967) for two independent observers respectively. The inter-observer reliability of the entire technique was good with an ICC of 0.752 (CI: 0.404-0.909). CONCLUSION We have successfully shown the feasibility and reliability of applying the 3D-FMBV technique to the neonatal brain in a healthy preterm population.

OBJECTIVE Superficial temporal artery–middle cerebral artery (STA-MCA) bypass surgery is an important therapy for symptomatic moyamoya disease. Its success depends on bypass function, which may be impaired by primary or secondary bypass insufficiency. Catheter angiography is the current gold standard to assess bypass function, whereas the diagnostic value of ultrasonography (US) has not been systematically analyzed so far. METHODS The authors analyzed 50 STA-MCA bypasses in 39 patients (age 45 ± 14 years [mean ± SD]; 26 female, 13 male). Bypass patency was evaluated by catheter angiography, which was performed within 24 hours after US. The collateral circulation through the bypass was classified into 4 types as follows: the bypass supplies more than two-thirds (type A); between one-third and two-thirds (type B); or less than one-third (type C) of the MCA territory; or there is bypass occlusion (type D). The authors assessed the mean blood flow velocity (BFV), the blood volume flow (BVF), and the pulsatility index (PI) in the external carotid artery and STA by duplex sonography. Additionally, they analyzed the flow direction of the MCA by transcranial color-coded sonography. US findings were compared between bypasses with higher (types A and B) and lower (types C and D) capacity. RESULTS Catheter angiography revealed high STA-MCA bypass capacity in 35 cases (type A: n = 22, type B: n = 13), whereas low bypass capacity was noted in the remaining 15 cases (type C: n = 12, type D: n = 3). The BVF values in the STA were 60 ± 28 ml/min (range 4–121 ml/min) in the former and 12 ± 4 ml/min (range 6–18 ml/min) in the latter group (p < 0.0001). Corresponding values of mean BFV and PI were 57 ± 21 cm/sec (range 16–100 cm/sec) versus 22 ± 8 cm/sec (range 10–38 cm/sec) (p < 0.0001) and 0.8 ± 0.2 (range 0.4–1.3) versus 1.4 ± 0.5 (range 0.5–2.4) (p < 0.0001), respectively. Differences in the external carotid artery were less distinct: BVF 217 ± 71 ml/min (range 110–425 ml/min) versus 151 ± 41 ml/min (range 87–229 ml/min) (p = 0.001); mean BFV 47 ± 17 cm/sec (range 24–108 cm/sec) versus 40 ± 7 cm/sec (range 26–50 cm/sec) (p = 0.15); PI 1.5 ± 0.4 (range 1.0–2.5) versus 1.9 ± 0.4 (range 1.2–2.6) (p = 0.009). A retrograde blood flow in the MCA was found in 14 cases (9 in the M1 and M2 segment; 5 in the M2 segment alone), and all of them showed a good bypass function (type A, n = 10; type B, n = 4). The best parameter (cutoff value) to distinguish bypasses with higher capacity from bypasses with lower capacity was a BVF in the STA ≥ 21 ml/min (sensitivity 100%, negative predictive value 100%, specificity 91%, positive predictive value 83%). CONCLUSIONS Duplex sonography is a suitable diagnostic tool to assess STA-MCA bypass function in moyamoya disease. Hemodynamic monitoring of the STA by US provides an excellent predictor of bypass patency.

Of all physiological systems, the cardiovascular system takes on the most profound adaptation in pregnancy to support fetal growth and development. The adaptations that arise are systemic and involve structural and functional changes that can be observed at the cerebral, central, peripheral, and microvascular beds. This includes, although is not limited to increased heart rate, stroke volume and cardiac output with negligible change to blood pressure, reductions in vascular resistance and cerebral blood flow velocity, systemic artery enlargement, enhanced endothelial function. All of this takes place to accommodate blood volume expansion and ensure adequate fetal and maternal oxygen delivery. In some instances, the demand placed on the vasculature can manifest as cardiovascular maladaptation and thus, cardiovascular complications can arise. Exercise is recommended in pregnancy because of its powerful ability to reduce the incidence and severity of cardiovascular complications in pregnancy. However, the mechanism by which it acts is poorly understood. The first aim of this review is to describe the systemic adaptations that take place in pregnancy. Secondly, this review aims to describe the influence of exercise on these systemic adaptations. It is anticipated that this review can comprehensively capture the extent of knowledge in this area while identifying areas that warrant further investigation.

The aim of this systematic review was to summarize the evidence on the acute and long-term effects of exercise training on PV, in both trained and untrained individuals and to examine associations between changes in %PVV and change in physical/physiological performance. Despite the status of participants and the exercise duration or intensity, all the acute studies reported a significant decrease of PV (effect size: 0.85

lood volume escalation during pregnancy leads to an increase in iron needs. Pregnant women are prone to maternal anemia that is caused by iron, folic acid, vitamins B2, B12, A, and C deficiency and may serve as causative factors that aggravate anemia. Concerning the problem, this clinical investigation determined the effect of antianemia supplementation and its combination with vitamin C on hemoglobin levels during pregnancy. This study is a quasi-experimental involving 34 patients who consumed antianemia supplements with or without vitamin C. The treatment group was given a combination of antianemia supplement Fe Fumarate 180 mg-Folic Acid 400 mcg and vitamin C 100 mg. The positive-control group was administrated with antianemia supplement Fe Fumarate 180 mg-Folic Acid 400 mcg. After 28 days, blood samples were taken to measure the hemoglobin levels. The hemoglobin levels were found to have a statistically significant difference (p

Blood loss (BL) during posterior spinal fusion for adolescent idiopathic scoliosis (AIS) may be estimated using a variety of unproven techniques. Patient care and research on BL are likely impacted by a lack of standardization. A novel FDA-approved blood volume (BV) analysis system (BVA-100 Blood Volume Analyzer) allows rapid processing with > 97% accuracy. The purpose of this study was to investigate common methods for BL estimation. BV assessment was performed with the BVA-100. After obtaining a baseline sample of 5 mL of blood, 1 mL of I-131-labeled albumin was injected intravenously over 1 min. Five milliliter blood samples were then collected at 12, 18, 24, 30, and 36 min post-injection. Intravenous fluid was minimized to maintain euvolemia. Salvaged blood was not administered during surgery. BL was estimated using several common techniques and compared to the BV measurements provided by the BVA-100 (BVABL). Thirty AIS patients were prospectively enrolled with major curves of 54° and underwent fusions of 10 levels. BL based on the BVA-100 (BVABL) was 519.2 [IQR 322.9, 886.2] mL. Previously published formulas all failed to approximate BVABL. Multiplying the cell saver volume return by 3 (CS3) approximates BVABL well with a Spearman correlation coefficient and ICC of 0.80 and 0.72, respectively. An extrapolated cell salvage-based estimator also showed high intraclass correlation coefficient (ICC) and Spearman coefficients with less bias than CS3. Published formulaic approaches do not approximate true blood loss. Multiplying the cell saver volume by 3 or using the cell salvage-based estimator had the highest correlation coefficient and ICC. Prospective cohort Level 2.

To investigate the impact of intraoperative blood transfusion on outcomes in patients who had major thoracic and lumber posterior spine instrumentation surgery. Retrospective study included patients who underwent major spine surgery between 2013 and 2017. Patients’ demographics, surgical charts, anesthesia charts, discharge charts and follow-up outpatient charts were reviewed. Data collection included: age, gender, BMI, Charlson Co-morbidity Index (CCI) scores, American Society of Anesthesiologists (ASA) scores, amount of estimated blood loss [% estimated blood volume (%EBV)], amount of blood transfused during surgery and post-surgery before discharge, number of fusion levels, pre- and postoperative hemoglobin (Hb) levels, and length of hospital stay. Also collected in-hospital postoperative complications (cardiovascular, pulmonary, infections and deaths). Patients’ postoperative intubation status data documented. Reviewed follow-up charts to document any complications. Sample size = 289; No transfusion = 92; transfusion = 197. Transfused patients were significantly older, p

We investigated the efficiency of mitoxantrone (MIT) and high-dose cytarabine (Ara-C) chemotherapy followed by G-CSF and G-CSF/GM-CSF treatments for the mobilization of peripheral blood stem cells (PBSCs) in patients with leukemia and lymphoma. MIT was intravenously injected at 10 mg/(m2·d) for 2 to 3 days, followed by Ara-C injected intravenously at 2 g/m2 every 12 hours for 1 to 2 days. When white blood cell count recovered from the lowest value, 5 to 7.5 μg/ (kg·d) G-CSF was administered in 23 patients for 5 to 7 successive days. Another 27 patients received 3-5 μg/ (kg·d) G-CSF and 3-5μg/ (kg·d) GM-CSF. Autologous peripheral blood mononuclear cells were collected. Levels of CFU-GM and CD34+ cells were determined after unfreezing. The CD34+ cells and CFU-GM yields of 27 patients in G-CSF plus GM-CSF combination group [(8.79±3.11)×106/kg, (3.52±1.34)×105/kg, respectively] were significantly higher than those of patients receiving G-CSF alone (n=23) [(6.14±2.06)×106/kg, (2.03±1.06)×105/kg, respectively (P < 0.05)]. No obvious changes of T lymphocyte subsets in patients were observed when using G-CSF/GM-CSF, but levels of CD34+ cells increased gradually (P>0.05). The end-point separation blood volume was all above trebling TBV. No severe complications were observed during the mobilization and collection. Autologous PBSCT obtained quick hematopoietic reconstitution. In conclusion, MA chemotherapy combined with G-CSF alone and G-CSF/GM-CSF can safely and effectively mobilize autologous PBSCs, while G-CSF plus GM-CSF is superior to G-CSF alone. Large volume leukapheresis is an important method to enhance the production rate of stem cells and decrease harvesting time.

Sublingual nitroglycerin (SL NTG) is useful for treating acute decompensated heart failure, possibly by increasing splanchnic capacitance and reducing left ventricular (LV) preload. We evaluated a radionuclide method to study these effects, initially in subjects without heart failure.Red blood cells were labelled by an in vitro method. Abdominal and chest images were obtained at rest, showing relative regional blood volumes. The abdomen was then re-imaged during progressive escalation of intrathoracic pressure using continuous positive airway pressure to assess baseline splanchnic capacitance (pressure-volume relationship, PVR) and compliance (slope of PVR). The procedure was repeated after 0.6 mg SL NTG, followed by chest images. Relative splanchnic blood volume increased at rest after SL NTG (P.002), signifying an increase in splanchnic capacitance. The slope of the splanchnic PVR decreased in proportion to the baseline PVR (P = .0014), signifying increased compliance. The relative pulmonary blood volume decreased in proportion to the increase in splanchnic blood volume (P = .01).A semi-quantitative radionuclide method demonstrated the effect of SL NTG for increasing splanchnic capacitance and compliance, with a proportional decrease in pulmonary blood volume. These data may be applied to quantitatively evaluate the importance of splanchnic vasodilation as a mechanism of LV preload reduction in the treatment of heart failure.NCT02425566.

BACKGROUND Bioelectrical impedance analysis (BIA) devices have been advocated to guide volume management in hemodialysis (HD) patients. We hypothesized that understanding the dynamics of fluid shifts in different body segments may provide additional insight on preventive measures to reduce the risk of intradialytic hypotension. METHODS A prospective observational study was conducted among 42 HD patients at risk of hypotension who were admitted as emergencies inpatient. RESULTS A total of 191 BIA measurements were made during the 42 HD sessions, and hypotension occurred during 52 measurements (27%). The extracellular water (ECW) to intracellular water ratio (EIR) was measured in different body segments and declined significantly only in the non-access arm with increasing HD session duration (β = -0.04; 95% confidence interval (CI): -0.05 to -0.03, p

Near-infrared spectroscopy (NIRS) signals quantify the oxygenated (ΔHbMbO(2)) and deoxygenated (ΔHHbMb) heme group concentrations. ΔHHbMb has been preferred to ΔHbMbO(2) in evaluating skeletal muscle oxygen extraction because it is assumed to be less sensitive to blood volume (BV) changes, but uncertainties exist on this assumption. To analyze this assumption, a computational model of oxygen transport and metabolism is used to quantify the effect of O(2) delivery and BV changes on the NIRS signals from a canine model of muscle oxidative metabolism (Sun Y, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Med Sci Sports Exerc 48: 2013–2020, 2016). The computational analysis accounts for microvascular (ΔHbO(2), ΔHHb) and extravascular (ΔMbO(2), ΔHMb) oxygenated and deoxygenated forms. Simulations predicted muscle oxygen uptake and NIRS signal changes well for blood flows ranging from resting to contracting muscle. Additional NIRS signal simulations were obtained in the absence or presence of BV changes corresponding to a heme groups concentration changes (ΔHbMb = 0–48 µM). Under normal delivery (Q = 1.0 L·kg(−1)·min(−1)) in contracting muscle, capillary oxygen saturation (So(2)) was 62% with capillary ΔHbO(2) and ΔHHb of ± 41 µΜ for ΔHbMb = 0. An increase of BV (ΔHbMb = 24 µΜ) caused a ΔHbO(2) decrease (16µΜ) almost twice as much as the increase observed for ΔHHb (9 µΜ). When So(2) increased to more than 80%, only ΔHbO(2) was significantly affected by BV changes. The analysis indicates that microvascular So(2) is a key factor in determining the sensitivity of ΔHbMbO(2) and deoxygenated ΔHHbMb to BV changes. Contrary to a common assumption, the ΔHHbMb is affected by BV changes in normal contracting muscle and even more in the presence of impaired O(2) delivery. NEW & NOTEWORTHY Deoxygenated is preferred to the oxygenated near-infrared spectroscopy signal in evaluating skeletal muscle oxygen extraction because it is assumed to be insensitive to blood volume changes. The quantitative analysis proposed in this study indicates that even in absence of skin blood flow effects, both NIRS signals in presence of either normal or reduced oxygen delivery are affected by blood volume changes. These changes should be considered to properly quantify muscle oxygen extraction by NIRS methods.

Various types of hemoglobin (Hb)-based oxygen carriers (HBOCs) have been developed as red blood cell substitutes for treating blood loss when blood is not available. Among those HBOCs, glutaraldehyde polymerized Hbs have attracted significant attention due to their facile synthetic route, and ability to expand the blood volume and deliver oxygen. Hemopure®, Oxyglobin®, and PolyHeme® are the most well-known commercially developed glutaraldehyde polymerized Hbs. Unfortunately, only Oxyglobin® was approved by the FDA for veterinary use in the United States, while Hemopure® and PolyHeme® failed phase III clinical trials due to their ability to extravasate from the blood volume into the tissue space which facilitated nitric oxide scavenging and tissue deposition of iron, which elicited vasoconstriction, hypertension and oxidative tissue injury. Fortunately, conjugation of poly (ethylene glycol) (PEG) on the surface of Hb is capable of reducing the vasoactivity of Hb by creating a hydration layer surrounding the Hb molecule, which increases its hydrodynamic diameter and reduces tissue extravasation. Several commercial PEGylated Hbs (MP4®, Sanguinate®, Euro-PEG-Hb) have been developed for clinical use with a longer circulatory half-life and improved safety compared to Hb. However, all of these commercial products exhibited relatively high oxygen affinity compared to Hb, which limited their clinical use. To dually address the limitations of prior generations of polymerized and PEGylated Hbs, this current study describes the PEGylation of polymerized bovine Hb (PEG-PolybHb) in both the tense (T) and relaxed (R) quaternary state via thiol-maleimide chemistry to produce an HBOC with low or high oxygen affinity. The biophysical properties of PEG-PolybHb were measured and compared with those of commercial polymerized and PEGylated HBOCs. T-state PEG-PolybHb possessed higher hydrodynamic volume and P50 than previous generations of commercial PEGylated Hbs. Both T- and R-state PEG-PolybHb exhibited significantly lower haptoglobin binding rates than the precursor PolybHb, indicating potentially reduced clearance by CD163 + monocytes and macrophages. Thus, T-state PEG-PolybHb is expected to function as a promising HBOC due to its low oxygen affinity and enhanced stealth properties afforded by the PEG hydration shell.

Aim Peri-/intaventricular hemorrhage (P/IVH) is a common condition in preterm neonates and is responsible for substantial adverse neurological outcome especially in extremely low birth weight infants. As hematocrit after birth is a surrogate marker for blood volume, this study aimed to evaluate the effect of initial hematocrit values after birth on P/IVH development in extreme low birth weight (ELBW) neonates. Patients and methods A prospective cohort analysis of 92 eligible ELBW neonates was performed. The relationship between initial hematocrit values in ELBW neonates after birth and subsequent development of P/IVH was examined. Results Twenty-nine of 92 infants developed P/IVH. There were significant differences in initial Hct and maximum carbon dioxide (max PCO2) in the first 3 days levels in the P/IVH group compared with no P/IVH group. Initial Hct level at birth in the P/IVH group were significantly lower than the no P/IVH group while max PCO2 in the first 3 days were found to be significantly high in the P/IVH group. There were no significant differences in other baseline demographic, perinatal, and neonatal characteristics while in univariate analysis, higher gestational age and initial Hct were associated with decreased likelihood of P/IVH. In multiple regression analysis after adjustment, only initial Hct remained significantly associated with P/IVH. There was no difference between the population by subgroups of IVH (IVH I-II and IVH III-IV) according to hematocrit and the severity of IVH. Conclusion Higher initial Hct at birth is associated with decreased P/IVH in ELBW infants. We hypothesized the argument that ELBW infants who have lower initial Hct at birth have less suboptimal volume status that predisposing lower cerebral blood flow and the resultant decrease in cerebral blood flow precede the development of P/IVH.

Hematocrit (Hct) values after the initiation of cardiopulmonary bypass (CPB) must be maintained appropriately to avoid perioperative complications. Therefore, an accurate prediction is required. However, the standard prediction equation often results in actual values that are lower than the predicted values. This study aimed to clarify the limits of agreement (LOA) and bias of the prediction equations and investigate better the prediction equations. A retrospective study was performed on adult patients between April 2015 and December 2020. Study 1 included 158 patients, and Study 2 included 55 patients. The primary outcomes were the LOA and bias between the predicted and measured Hct values after the initiation of CPB, and two studies were conducted. In Study 1, total blood volume (TBV) was estimated, and the new blood volume index (BVI) was calculated. BVI was also evaluated for the overall value and gender differences. Therefore, the patient's background was compared by gender differences. In, Study 2 the conventional predicted equation (Eq. 1), the predicted equation using the new BVI (Eq. 2), and the predicted equation using the new BVI including physiological factors in the TBV equation (Eq. 3) were compared. In Study 1, BVI was 53 (44-67) mL/kg. In Study 2, bias ± LOA was - 2.5 ± 6.8% for Eq. 1, 0.1 ± 6.6% for Eq. 2, and 0.4 ± 6.2% for Eq. 3. The new equation is expected to predict the Hct value after the initiation of CPB with better LOA and bias than the conventional equation.

Background Iodine material images (aka iodine basis images) generated from dual energy CT (DECT) have been used to assess potential perfusion defects in the pulmonary parenchyma. However, iodine material images do not provide the needed absolute quantification of the pulmonary blood pool, as materials with effective atomic numbers (Zeff ) different from those of basis materials may also contribute to iodine material images, thus confounding the quantification of perfusion defects. Purpose The purposes of this work were to (i) demonstrate the limitations of iodine material images in pulmonary perfusion defect quantification and (ii) develop and validate a new quantitative biomarker using effective atomic numbers derived from DECT images. Methods The quantitative relationship between the perfusion blood volume (PBV) in pulmonary parenchyma and the effective atomic number (Zeff ) spatial distribution was studied to show that the desired quantitative PBV maps are determined by the spatial maps of Zeff as PBVZeff (x) = a Zeff β (x) + b, where a, b, and β are three constants. Namely, quantitative PBVZeff is determined by Zeff images instead of the iodine basis images. Perfusion maps were generated for four human subjects to demonstrate the differences between conventional iodine material image-based PBV (PBViodine ) derived from two-material decompositions and the proposed PBVZeff method. Results Among patients with pulmonary emboli, the proposed PBVZeff maps clearly show the perfusion defects while the PBViodine maps do not. Additionally, when there are no perfusion defects present in the derived PBV maps, no pulmonary emboli were diagnosed by an experienced thoracic radiologist. Conclusion Effective atomic number based quantitative PBV maps provide the needed sensitive and specific biomarker to quantify pulmonary perfusion defects. This article is protected by copyright. All rights reserved.

The work deals with the current state of the problem of creation and clinical use of blood substitutes with gas transport function. Blood shortage is an important healthcare problem globally anticipated to become more problematic as people live longer and donor numbers reduces. So, there is a need for an alternative red cell product. The technological directions for the development of blood substitutes with gas transport function are described. The analysis of conducted researches of blood substitutes on the basis of modified hemoglobin, perfluorocarbons, as well as the use of molecular, cellular and nanotechnologies was carried out. The term “blood substitute” does not accurately describe the current candidate products because they typically have only two limited functions: carrying and delivering oxygen and augmenting blood volume. Although no single product can yet imitate all the properties of the blood, substantial progress has been made, especially in the development of hemoglobin based oxygen carriers. The perfluorocarbons are synthetic cyclic or linear hydrocarbons occasionally containing oxygen or nitrogen atoms, and the hydrogen atoms are replaced by fluorine atoms in them. They easily solubilize and release gases without interacting with them. The quantity of gas dissolved is linearly related to its partial pressure. The article presents the results of experimental study and clinical use (1984–2010) of perftorane in acute hemorrhage and hemorrhagic shock, traumatic brain injury, postresuscitation disease, acute myocardial infarction, septic shock, acute poisoning, fat embolism, as a component of cardioplegia under cardiosurgical interventions, vascular surgery and transplantology. Potential advantages of the use of blood substitutes with gas transport function as compared to allogeneic blood are demonstrated. The current state of the problem of creating and studying blood substitutes with gas transport function allows us to conclude that at present this group of drugs remains a potential that has not yet been realized, since they are not literally blood substitutes. Existing single drugs with gas transport function that have been used clinically cannot completely replace the blood function and do not allow to stop using donor red blood cells, but they allow you to gain precious time, making a decisive contribution to saving patients in critical conditions and to encourage further development of more modern blood substitutes. We are deeply convinced that these blood substitutes, which model the most important oxygen transfer function of the blood, will take a worthy place in the future among various methods that is an alternative to the use of donor blood.

The utility of tranexamic acid (TXA) in patients with Marfan syndrome (MFS) is uncertain given associated aberrations within the vasculature and clotting cascade. Therefore, this study aimed to assess the association of TXA use with intraoperative blood loss and allogeneic blood transfusions in patients with MFS who underwent spinal arthrodesis. We queried our institutional database for MFS patients who underwent spinal arthrodesis for scoliosis between 2000 and 2020 by one surgeon. We excluded procedures spanning

Background Currently, the accepted effective method for assessing blood volume status, such as measuring central venous pressure (CVP) and mean pulmonary artery pressure (mPAP), is invasive. The purpose of this study was to explore the feasibility and validity of the ratio of the femoral vein diameter (FVD) to the femoral artery diameter (FAD) for predicting CVP and mPAP and to calculate the cut-off value for the FVD/FAD ratio to help judge a patient’s fluid volume status. Methods In this study, 130 patients were divided into two groups: in group A, the FVD, FAD, and CVP were measured, and in group B, the FVD, FAD, and mPAP were measured. We measured the FVD and FAD by ultrasound. We monitored CVP by a central venous catheter and mPAP by a Swan-Ganz floating catheter. Pearson correlation coefficients were calculated. The best cut-off value for the FVD/FAD ratio for predicting CVP and mPAP was obtained according to the receiver operating characteristic (ROC) curve. Results The FVD/FAD ratio was strongly correlated with CVP (R = 0.87, P P 2O, and an FVD/FAD ratio ≤ 1.467 had the best test characteristics to predict a CVP ≤ 10 cmH2O. An FVD/FAD ratio ≥ 2.03 had the best test characteristics to predict an mPAP ≥ 25 mmHg. According to the simple linear regression curve of the FVD/FAD ratio and CVP, when the predicted CVP ≤ 5 cmH2O, the FVD/FAD ratio was ≤ 0.854. Conclusion In this study, the measurement of the FVD/FAD ratio obtained via ultrasound was strongly correlated with CVP and mPAP, providing a non-invasive method for quickly and reliably assessing blood volume status and providing good clinical support.

International audience; It is important to develop a better understanding of placental insufficiency given its role in common maternofetal complications such as preeclampsia and fetal growth restriction. Functional magnetic resonance imaging offers unprecedented techniques for exploring the placenta under both normal and pathological physiological conditions. Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) is an established and very robust method to investigate the microcirculatory parameters of an organ and more specifically its perfusion. It is currently a gold standard in the physiological and circulatory evaluation of an organ. Its application to the human placenta could enable to access many microcirculatory parameters relevant to the placental function such as organ blood flow, fractional blood volume, and permeability surface area, by the acquisition of serial images, before, during, and after administration of an intravenous contrast agent. Widely used in animal models with gadolinium-based contrast agents, its application to the human placenta could be possible if the safety of contrast agents in pregnancy is established or they are confirmed to not cross the placenta.

Objective\ud To estimate iron losses and disease severity following 19th century bloodletting in patients with pneumonia.\ud \ud Study design and setting\ud Benefits of bloodletting in pneumonia patients were contested during the 19th century. Although large blood volumes during infection were removed there was no systematic data collection assessing efficacy and knowledge of iron composition of blood was rudimentary. This observational analysis of historical data quantifies iron losses in pneumonia cases in relation to disease severity.\ud \ud Results\ud Based on one detailed case series average blood volume removed for survivors was 830 ml (range 114 - 2272 ml), and mean recovery times were shorter in patients bled within 2 days of illness (p2 days of illness (p=0.012). Across several European hospitals average case fatality in pneumonia patients receiving phlebotomy was higher than in those treated without phlebotomy (19.9% vs 12.8%, OR 1.55, 95% CI 1.38-1.74, P

Purpose Sympathetic activation results in a functional distribution of venous blood from the unstressed reservoir to the hemodynamically active stressed compartment. Such redistribution has been hypothesized to contribute importantly to the elevated filling pressures observed in decompensated heart failure and cardiogenic shock (CS). We recently reported a novel computational method to estimate SBV by fitting measured hemodynamic data from patients to outputs from a cardiovascular model. We hypothesized that estimated stressed blood volume (eSBV) may correlate with severity and clinical outcomes in cardiogenic shock. Methods Hemodynamic parameters including eSBV were compared among a subset of patients from the Cardiogenic Shock Working Group (CSWG) registry who had a complete set of hemodynamic data. eSBV was compared across shock etiologies (AMI vs HF-CS), SCAI stage, and between survivors and non-survivors. Results Among 528 CSWG registry patients analyzed, 25.4% had AMI-CS and 61.9% had HF-CS. Mean eSBV was 2423 ± 531 mL/70 kg (normal value ∼1500 mL) and was similar between the AMI-CS and HF-CS subgroups (2421 ± 478 vs 2342 ± 599 mL/70kg, p=0.90). eSBV increased with increasing SCAI stage (B, 2029 ± 540; C, 2305 ± 505; D, 2496 ± 507; E, 2707 ± 420 mL/70 kg, p Conclusion eSBV is a novel integrated index of congestion which correlates with shock severity. eSBV was higher in patients with HF-CS who died while no difference was observed in AMI-CS, suggesting that congestion may play a more significant role in the deterioration of patients with HF-CS.

BACKGROUND: Aerobatic pilots must withstand high and sudden acceleration forces (Gz) up to 10 Gz. The physiological consequences of such a succession of high and abrupt positive and negative Gz on the human body over time remain mostly unknown. This case report emphasizes changes in physiological factors such as cerebral oxygenation and heart rate dynamics collected in real aerobatic flights.CASE REPORT: A 37-yr-old man, experienced in aerobatic flying, voluntarily took part in this study. During two flight runs (15-20 min), the pilot performed aerobatic maneuvers with multiple high (10 Gz) positive and negative accelerations. During the flights he wore a Polar heart rate sensor while cerebral oxygenation was measured continuously over his prefrontal cortex via near-infrared spectroscopy (NIRS). NIRS allows for measurement of the relative concentration changes of oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb), making it possible to determine cerebral oxygenation and hemodynamic status.DISCUSSION: The continuous in-flight monitoring of O2Hb and HHb revealed the large effects of successive positive and negative Gz exposures on cerebral hemodynamics alterations. The results showed a significant and positive correlation between changes in Gz exposures and O2Hb concentration. This case report highlights that NIRS provides some valuable and sensitive indicators for the monitoring of cerebral hemodynamics during aerobatic flights exposed to multiple and high acceleration forces. To our knowledge, this first study quantifying cerebral oxygenation changes in aerobatics opens the way for the assessment of individual physiological responses and tolerance in pilots to repeated high Gz during real flights.Fresnel E, Dray G, Pla S, Jean P, Belda G, Perrey S. Cerebral oxygenation responses to aerobatic flight. Aerosp Med Hum Perform. 2021; 92(10):838-842.

Цель исследования: обоснование и внедрение в интенсивную терапию гепатоспланхнической ишемии при политравме эмпирической реоксигенации общего и локального действия. В исследование включены 85 пострадавших с политравмой, в структуру которой входила черепно-мозговая травма: по современной клинической классификации — ушиб головного мозга легкой и средней степени тяжести. Условия для включения в исследование: наличие более 32 баллов по шкале тяжести повреждений — Inyuri Severity Score (ISS), тяжесть состояния по шкале Acute Physiology and Chronic Health Evaluation (APACHE ІІ) — 25 и более баллов. Клинико-биохимические исследования проводили на следующих этапах: при поступлении (1-й этап), через 12–24 часа после начала интенсивной терапии (2-й этап), 3-и, 5-е, 7-е сутки (3, 5, 7-й этапы соответственно). Клиническое наблюдение осуществляли до 32 суток от момента травмы. При поступлении в стационар наблюдались определенные отличия в зависимости от исхода заболевания. У пострадавших с последующим летальным исходом были выше кровопотеря (на 27,65 %, р

Работа посвящена изучению особенностей системной гемодинамики у рожениц при возникновении акушерского кровотечения и выявлению прогностической роли гемодинамических параметров, используемых для оценки реакции системного кровообращения на потерю объема циркулирующей крови. Исследования проведены у 32 рожениц (средний возраст 29,7 ± 3,4 года, площадь поверхности тела — 1,96 ± 0,30 м2), у которых роды были осложнены акушерским кровотечением. В результате исследований было подтверждено преимущество использования показателей пульсового давления в качестве раннего детектора гиповолемии и тяжести кровопотери, которая часто компенсируется симпатическими рефлексами и скрывается за нормальными значениями артериального давления и центральными гемодинамическими показателями. При этом статистически достоверные изменения пульсового давления наблюдались начиная с кровопотери, которая составляла около/свыше 12 % объема циркулирующей крови.

The objective of this study is to describe the compensatory reserve index (CRI) baseline values in a healthy cohort of healthy pediatric patients and evaluate the existing correlation with other physiological parameters that influence compensatory hemodynamic mechanisms. CRI is a computational algorithm that has been broadly applied to non-invasively estimate hemodynamic vascular adaptations during acute blood loss. So far, there is a lack of baseline values from healthy individuals, which complicates accurately estimating the severity of the hemodynamic compromise. Additionally, the application of this technology in pediatric populations is limited to a few reports, highlighting a marked variability by age, weight, and other physiological parameters. The CRI of 205 healthy subjects from 0 to 60 years of age were prospectively evaluated from January to February 2020 at several public outpatient clinics in El Salvador; vital signs and sociodemographic data were also collected during this period. After data collection, baseline values were classified for each age group. Multiple correlation models were tested between the CRI and the other physiological parameters. CRI value varies significantly for each age group, finding for patients under 18 years old a mean value lower than 0.6, which is currently considered the lower normal limit for adults. CRI presents strong correlations with other physiological variables such as age, weight, estimated blood volume, and heart rate (R > 0.8, R2 > 0.6, p

Background Blood transfusion remains important in the treatment of patients with sickle cell disease (SCD). However, alloimmunization after blood transfusion is associated with patient morbidity and mortality. Triple-knockout (TKO) pigs (i.e., pigs in which the three known xenoantigens to which humans have anti-pig antibodies have been deleted) may be an alternative source of RBCs for these patients because many humans have no preformed antibodies to TKO pig RBCs (pRBCs). Methods and materials In an in vitro study, plasma from alloimmunized (n = 12) or non-alloimmunized (n = 12) SCD patients was used to determine IgM/IgG binding to, and CDC of, TKO pRBCs. In an in vivo study, after an estimated 25% of blood volume was withdrawn from two capuchin monkeys, CFSE-labeled TKO pRBCs were transfused. Loss of TKO pRBCs was monitored by flow cytometry, and 7 weeks later, 25% of blood was withdrawn, and CFSE-labeled monkey RBCs were transfused. Results The in vitro study demonstrated that plasma from neither alloimmunized nor non-alloimmunized SCD patients bound IgM/IgG to, or induced CDC of, TKO pRBCs. In the in vivo study, survival of TKO pRBCs in the two capuchin monkeys was of 5 and 7 days, respectively, whereas after allotransfusion, survival was >28 days. Conclusions In conclusion, (1) in the present limited study, no antibodies were detected that cross-reacted with TKO pRBCs, and (2) TKO pigs may possibly be an alternate source of RBCs in an emergency if no human RBCs are available.

Ageing is associated with endothelial dysfunction and reduced cerebral blood flow and oxygenation. The present study aimed to investigate whether turmeric supplementation could improve cerebral oxygenation and blood volume during brain activation via dynamic handgrip exercise in older males and females. Twelve older males and females were studied using a double-blind, placebo-controlled, cross-over design. Participants ingested turmeric root extract or placebo. Heart rate and blood pressure were measured before and 2 hours after supplementation. Afterward, the exercise protocol was started, and cerebral oxygenation and blood volume were evaluated. During exercise, changes in cerebral oxygenation were higher after turmeric extract supplementation, as was blood volume compared to placebo. Changes in heart rate, systolic blood pressure, and diastolic blood pressure were not significant. The current findings indicate the potential for curcumin as an intervention for improving cerebral oxygenation and blood volume changes in older males and females.

Background: Individuals with left ventricular (LV) hypertrophy and elevated cardiac biomarkers in middle age are at increased risk for the development of heart failure with preserved ejection fraction. Prolonged exercise training reverses the LV stiffening associated with healthy but sedentary aging; however, whether it can also normalize LV myocardial stiffness in patients at high risk for heart failure with preserved ejection fraction is unknown. In a prospective, randomized controlled trial, we hypothesized that 1-year prolonged exercise training would reduce LV myocardial stiffness in patients with LV hypertrophy. Methods: Forty-six patients with LV hypertrophy (LV septum >11 mm) and elevated cardiac biomarkers (N-terminal pro-B-type natriuretic peptide [>40 pg/mL] or high-sensitivity troponin T [>0.6 pg/mL]) were randomly assigned to either 1 year of high-intensity exercise training (n=30) or attention control (n=16). Right-heart catheterization and 3-dimensional echocardiography were performed while preload was manipulated using both lower body negative pressure and rapid saline infusion to define the LV end-diastolic pressure-volume relationship. A constant representing LV myocardial stiffness was calculated from the following: P=S×[Exp {a (V–V 0 )}–1], where “P” is transmural pressure (pulmonary capillary wedge pressure – right atrial pressure), “S” is the pressure asymptote of the curve, “V” is the LV end-diastolic volume index, “V 0 ” is equilibrium volume, and “a” is the constant that characterizes LV myocardial stiffness. Results: Thirty-one participants (exercise group [n=20]: 54±6 years, 65% male; and controls (n=11): 51±6 years, 55% male) completed the study. One year of exercise training increased max by 21% (baseline 26.0±5.3 to 1 year later 31.3±5.8 mL·min –1 ·kg –1 , P P =0.0004), whereas there was no significant change in max in controls (baseline 24.6±3.4 to 1 year later 24.2±4.1 mL·min –1 ·kg –1 , P =0.986). LV myocardial stiffness was reduced (right and downward shift in the end-diastolic pressure-volume relationship; LV myocardial stiffness: baseline 0.062±0.020 to 1 year later 0.031±0.009), whereas there was no significant change in controls (baseline 0.061±0.033 to 1 year later 0.066±0.031, interaction P =0.001). Conclusions: In patients with LV hypertrophy and elevated cardiac biomarkers (stage B heart failure with preserved ejection fraction), 1 year of exercise training reduced LV myocardial stiffness. Thus, exercise training may provide protection against the future risk of heart failure with preserved ejection fraction in such patients. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03476785.

BACKGROUND Owing to its simplicity, speed, small incision, and low cost, peripheral blood collection is widely used in routine blood testing. However, there are certain differences between the detection results of peripheral and venous blood specimens. This investigation and analysis aimed to investigate and analyze the status and opinions of laboratory physicians on the application of peripheral blood for routine blood testing. METHODS A questionnaire was used to investigate and analyze the current status of laboratory physicians with regards to routine peripheral blood testing. The content of the questionnaire included the following aspects: the proportion of peripheral blood specimens, the difficulty of detecting peripheral blood, factors affecting the results of peripheral blood specimens, the proportion of the simultaneous detection of blood test and C-reactive protein (CRP), as well as the proportion and ideals of hypersensitive CRP (hs-CRP), which included a total of 10 re-examination rules. RESULTS Laboratory physicians from 410 hospitals participated in the investigation. The proportion of routine blood tests using peripheral blood specimens in the laboratory departments of tertiary hospitals was low (P=0.006). Difficulties in routine blood tests with peripheral blood specimens were dominated by insufficient blood volume (67.8%). The factors affecting the results of routine blood tests with peripheral blood specimens were dominated by the mixing method (86.6%). When abnormal results were determined by routine blood tests using peripheral blood specimens, they were retested most commonly by making slide smears (82.4%) or re-examined using the remaining peripheral blood (66.1%). The same rules for re-examination of peripheral and venous blood were applied in most medical institutions (86.1%). When the platelet count decreased in routine blood tests using peripheral blood samples, the most common measures included sample agglutination checks (88.5%), instrument alarm message checks (82.4%), and making slide smears for re-examination (73.6%). More laboratory physicians expected blood analyzers to be integrated instruments that could provide both routine blood and hs-CRP testing (80.5%). CONCLUSIONS There are numerous difficulties in routine blood testing using peripheral blood, and thus, more convenient and accurate blood analysis instruments should be developed.

Hypovolemia remains the leading cause of preventable death in trauma cases. Recent research has demonstrated that using noninvasive continuous waveforms rather than traditional vital signs improves accuracy in early detection of hypovolemia to assist in triage and resuscitation. This work evaluates random forest models trained on different subsets of data from a pig model (n = 6) of absolute (bleeding) and relative (nitroglycerin-induced vasodilation) progressive hypovolemia (to 20% decrease in mean arterial pressure) and resuscitation. Features for the models were derived from a multi-modal set of wearable sensors, comprised of the electrocardiogram (ECG), seismocardiogram (SCG) and reflective photoplethysmogram (RPPG) and were normalized to each subject.s baseline. The median RMSE between predicted and actual percent progression towards cardiovascular decompensation for the best model was 30.5% during the relative period, 16.8% during absolute and 22.1% during resuscitation. The least squares best fit line over the mean aggregated predictions had a slope of 0.65 and intercept of 12.3, with an $R^2$ value of 0.93. When transitioned to a binary classification problem to identify decompensation, this model achieved an AUROC of 0.80. This study: a) developed a global model incorporating ECG, SCG and RPPG features for estimating individual-specific decompensation from progressive relative and absolute hypovolemia and resuscitation; b) demonstrated SCG as the most important modality to predict decompensation; c) demonstrated efficacy of random forest models trained on different data subsets; and d) demonstrated adding training data from two discrete forms of hypovolemia increases prediction accuracy for the other form of hypovolemia and resuscitation.

Background Hidden blood loss (HBL) represents an important complication of unilateral biportal endoscopic (UBE) spine surgery. This study aimed to evaluate HBL and its possible risk factors among patients undergoing UBE surgery for lumbar degenerative diseases. Methods This multicentric retrospective study was conducted in 3 different medical centers between July 2020 and April 2021. Data of patients who underwent UBE surgery were extracted by electronic medical record system. The patient’s demographic characteristics and blood loss-related parameters were recorded. We calculated the amount of HBL and explored the association between patient’s characteristics and HBL using Pearson or Spearman correlation analysis. Multivariate linear regression analysis was conducted to identify independent risk factors of HBL. Results A total of 136 patients (55 females and 81 males, age range 43 to 74 years) were included in this study. A substantial amount of HBL (469.5 ± 195.3 ml, 57.6% of TBL, total blood loss) occurred following UBE surgery. Multiple linear regression analysis indicated that the risk factors of HBL were as follows: age (P = 0.000), number of fusion levels (P = 0.015), American Society of Anesthesiologists (ASA) classification (P = 0.046), surgery time (P = 0.017), patient’s blood volume (PBV, P = 0.026), total blood loss (TBL, P = 0.001), postoperative (i.e., day 2 or 3) hematocrit (Hct, P = 0.034), Hct loss (P = 0.005), and fibrinogen (P = 0.028). Conclusions A certain amount of HBL occurs in UBE surgery and cannot be ignored in daily clinical practice. The age, number of fusion levels, ASA classification, surgery time, PBV, TBL, postoperative Hct, Hct loss, and fibrinogen are independent risk factors for HBL.

The high-altitude maladaptation syndrome known as chronic mountain sickness (CMS) is characterized by polycythemia and is associated with proteinuria despite unaltered glomerular filtration rate. However, it remains unclear if indigenous highlanders with CMS have altered volume regulatory hormones. We assessed NH2-terminal pro-B-type natriuretic peptide (NT pro-BNP), plasma aldosterone concentration, plasma renin activity, kidney function (urinary microalbumin, glomerular filtration rate), blood volume, and estimated pulmonary artery systolic pressure (ePASP) in Andean males without ( n = 14; age = 39 ± 11 yr) and with ( n = 10; age = 40 ± 12 yr) CMS at 4,330 m (Cerro de Pasco, Peru). Plasma renin activity (non-CMS: 15.8 ± 7.9 ng/mL vs. CMS: 8.7 ± 5.4 ng/mL; P = 0.025) and plasma aldosterone concentration (non-CMS: 77.5 ± 35.5 pg/mL vs. CMS: 54.2 ± 28.9 pg/mL; P = 0.018) were lower in highlanders with CMS compared with non-CMS, whereas NT pro-BNP was not different between groups (non-CMS: 1394.9 ± 214.3 pg/mL vs. CMS: 1451.1 ± 327.8 pg/mL; P = 0.15). Highlanders had similar total blood volume (non-CMS: 90 ± 15 mL·kg−1vs. CMS: 103 ± 18 mL·kg−1; P = 0.071), but Andeans with CMS had greater total red blood cell volume (non-CMS: 46 ± 10 mL·kg−1vs. CMS: 66 ± 14 mL·kg−1; P < 0.01) and smaller plasma volume (non-CMS: 43 ± 7 mL·kg−1vs. CMS: 35 ± 5 mL·kg−1; P = 0.03) compared with non-CMS. There were no differences in ePASP between groups (non-CMS: 32 ± 9 mmHg vs. CMS: 31 ± 8 mmHg; P = 0.6). A negative correlation was found between plasma renin activity and glomerular filtration rate in both groups (group: r = −0.66; P < 0.01; non-CMS: r = −0.60; P = 0.022; CMS: r = −0.63; P = 0.049). A smaller plasma volume in Andeans with CMS may indicate an additional CMS maladaptation to high altitude, causing potentially greater polycythemia and clinical symptoms.

Background: We previously explained why acardiac twinning occurs in the first trimester. We raised the question why a sudden demised monochorionic twin beyond the first trimester does not lead to acardiac twinning. We argued that exsanguinated blood from the live twin would strongly increase the demised twins' vascular resistance, preventing its perfusion and acardiac onset. However, our current hypothesis is that perfusion of the demised twin does occur but that it is insufficient for onset of acardiac twinning. Methods: We analyzed blood pressures and flows in a vascular resistance model of a monochorionic twin pregnancy where one of the fetuses demised. The resistance model consists of a demised twin with a (former) placenta, a live twin and its placenta, and arterioarterial (AA) and venovenous placental anastomoses. We assumed that only twins with a weight of at least 33% of normal survived the first trimester and that exsanguination of more than 50% of its blood volume is fatal for the live twin. Results: At 20 weeks, only AA anastomoses with radii ≲1 mm keep the exsanguinated blood volume below 50%. Then, perfusion of the deceased body with arterial blood from the live fetus is about 5–40 times smaller than when that body was alive. Beyond 20 weeks, this factor is even smaller. At 14 weeks, this factor is at most 2. Conclusion: We hypothesize that this small perfusion flow of arterial blood prevents further growth of the deceased body and hence precludes onset of acardiac twinning.

Blood vessel networks of living organisms continuously adapt their structure under the influence of hemodynamic and metabolic stimuli. For a fixed vessel arrangement, blood flow characteristics still depend crucially on the morphology of each vessel. Vessel diameters adapt dynamically according to internal and external stimuli: Endothelial wall shear stress, intravascular pressure, flow-dependent metabolic stimuli, and electrical stimuli conducted from distal to proximal segments along vascular walls. Pries et al. formulated a theoretical model involving these four local stimuli to simulate long-term changes of vessel diameters during structural adaption of microvascular networks. Here we apply this vessel adaptation algorithm to synthetic arteriovenous blood vessel networks generated by our simulation framework “Tumorcode”. We fixed the free model parameters by an optimization method combined with the requirement of homogeneous flow in the capillary bed. We find that the local blood volume, surface to volume ratio and branching ratio differs from networks with radii fulfilling Murray’s law exactly to networks with radii obtained by the adaptation algorithm although their relation is close to Murray’s law.