Decrease of haemoconcentration reliably detects hydrostatic pulmonary oedema in dyspnoeic patients in the emergency department - a machine learning approach.

BACKGROUND: Haemoglobin variation (ΔHb) induced by fluid transfer through the intestitium has been proposed as a useful tool for detecting hydrostatic pulmonary oedema (HPO). However, its use in the emergency department (ED) setting still needs to be determined. METHODS: In this observational retrospective monocentric study, ED patients admitted for acute dyspnoea were enrolled. Hb values were recorded both at ED presentation (T0) and after 4 to 8 h (T1). ΔHb between T1 and T0 (ΔHbT1-T0) was calculated as absolute and relative value. Two investigators, unaware of Hb values, defined the cause of dyspnoea as HPO and non-HPO. ΔHbT1-T0 ability to detect HPO was evaluated. A machine learning approach was used to develop a predictive tool for HPO, by considering the ability of ΔHb as covariate, together with baseline patient characteristics. RESULTS: Seven-hundred-and-six dyspnoeic patients (203 HPO and 503 non-HPO) were enrolled over 19 months. Hb levels were significantly different between HPO and non-HPO patients both at T0 and T1 (p < 0.001). ΔHbT1-T0 were more pronounced in HPO than non-HPO patients, both as relative (-8.2 [-11.2 to -5.6] vs. 0.6 [-2.1 to 3.3] %) and absolute (-1.0 [-1.4 to -0.8] vs. 0.1 [-0.3 to 0.4] g/dL) values (p < 0.001). A relative ΔHbT1-T0 of -5% detected HPO with an area under the receiver operating characteristic curve (AUROC) of 0.901 [0.896-0.906]. Among the considered models, Gradient Boosting Machine showed excellent predictive ability in identifying HPO patients and was used to create a web-based application. ΔHbT1-T0 was confirmed as the most important covariate for HPO prediction. CONCLUSIONS: ΔHbT1-T0 in patients admitted for acute dyspnoea reliably identifies HPO in the ED setting. The machine learning predictive tool may represent a performing and clinically handy tool for confirming HPO.

Prevalence of massively diluted bone marrow cell samples aspirated from patients with myelodysplastic syndromes (MDS) or suspected of MDS: A retrospective analysis of nationwide samples in Japan.

Bone marrow (BM) examination is a key element in the diagnosis and prognostic grading of myelodysplastic syndromes (MDSs), and obtaining adequate BM cell samples is critical for accurate test results. Massive haemodilution of aspirated BM samples is a well-known problem; however, its incidence in patients with MDS has not been well studied. We report the first study to examine the incidence of massive haemodilution in nationwide BM samples aspirated from patients diagnosed with or suspected of MDS in Japan. Among 283 cases available for analysis, BM smears from 92 cases (32.5%) were hypospicular (massively haemodiluted) and, particularly, no BM particles were observed in 52 cases (18.4%). Regarding hypospicular cases, we examined how the doctors in charge interpreted the BM smears of their patients. In only 19 of 92 cases (20.7%), doctors realised that the BM smears were haemodiluted. Furthermore, the BM biopsy, which can help diagnose hypospicular cases, was oftentimes not performed when the haemodilution was overlooked by doctors (not performed in 50 of 73 such cases). These real-world data highlight that not only researchers who are working to improve diagnostic tests but also clinicians who perform and use diagnostic tests must realise this common and potentially critical problem.

Revisiting the most often used item in the haematological tool box-The extent of haemodilution in bone marrow aspirates.

In this issue, a nationwide retrospective Japanese study finds that, in a second opinion setting, one-third of bone marrow aspirates from patients suspected of myelodysplastic syndromes are heavily haemodiluted. Moreover, in four-fifths of such cases, the failure to obtain the correct material for diagnosis went undetected by the referring institution. These data are intriguing, but given their special set-up, caution should be exerted in transposing them to other countries. Commentary on: Ogata et al. Prevalence of massively diluted bone marrow cell samples aspirated from patients with myelodysplastic syndromes (MDS) or suspected MDS: A retrospective analysis of nationwide samples in Japan. Br J Haematol 2024;204:1856-1861.

Cerebral blood flow regulation in hypobaric hypoxia: role of haemoconcentration.

During acute hypoxic exposure, cerebral blood flow (CBF) increases to compensate for the reduced arterial oxygen content (CaO2). Nevertheless, as exposure extends, both CaO2 and CBF progressively normalize. Haemoconcentration is the primary mechanism underlying the CaO2 restoration and may therefore explain, at least in part, the CBF normalization. Accordingly, we tested the hypothesis that reversing the haemoconcentration associated with extended hypoxic exposure returns CBF towards the values observed in acute hypoxia. Twenty-three healthy lowlanders (12 females) completed two identical 4-day sojourns in a hypobaric chamber, one in normoxia (NX) and one in hypobaric hypoxia (HH, 3500 m). CBF was measured by ultrasound after 1, 6, 12, 48 and 96 h and compared between sojourns to assess the time course of changes in CBF. In addition, CBF was measured at the end of the HH sojourn after hypervolaemic haemodilution. Compared with NX, CBF was increased in HH after 1 h (P = 0.001) but similar at all later time points (all P > 0.199). Haemoglobin concentration was higher in HH than NX from 12 h to 96 h (all P < 0.001). While haemodilution reduced haemoglobin concentration from 14.8 ± 1.0 to 13.9 ± 1.2 g·dl-1 (P < 0.001), it did not increase CBF (974 ± 282 to 872 ± 200 ml·min-1; P = 0.135). We thus conclude that, at least at this moderate altitude, haemoconcentration is not the primary mechanism underlying CBF normalization with acclimatization. These data ostensibly reflect the fact that CBF regulation at high altitude is a complex process that integrates physiological variables beyond CaO2. KEY POINTS: Acute hypoxia causes an increase in cerebral blood flow (CBF). However, as exposure extends, CBF progressively normalizes. We investigated whether hypoxia-induced haemoconcentration contributes to the normalization of CBF during extended hypoxia. Following 4 days of hypobaric hypoxic exposure (corresponding to 3500 m altitude), we measured CBF before and after abolishing hypoxia-induced haemoconcentration by hypervolaemic haemodilution. Contrary to our hypothesis, the haemodilution did not increase CBF in hypoxia. Our findings do not support haemoconcentration as a stimulus for the CBF normalization during extended hypoxia.

Effectiveness, safety and indications of acute normovolemic haemodilution in total knee arthroplasty.

Total knee arthroplasty (TKA) is the most cost-effective, and potent method for the treatment of end-stage knee osteoarthritis. Acute normovolemic haemodilution (ANH) can effectively replace the need for allogeneic transfusions due to the high amount of bleeding during TKA. However, more studies are needed to prove the efficacy and safety of ANH and to clarify its indications in the field of knee replacement. Medical records from June 1, 2019 to June 1, 2021 were searched and grouped according to inclusion and exclusion criteria. PART I: 58 patients with ANH during TKA were selected as the ANH group (n = 58), and 58 patients with allogeneic transfusion were chosen as the control group (n = 58). PART II: Patients with anaemia were divided into the ANH group (n = 18) and the control group (n = 12). PART I: The postoperative inflammatory index and serum albumin in the ANH group were significantly lower than those in the control group. No significant difference was observed in the theoretical loss of red blood cells, postoperative renal function, liver function, cardiac function and biochemical ion index between the two groups. The effective rate of ANH in the normal haemoglobin group was significantly lower than that in the anaemia group. PART II: In patients with anaemia, the theoretical loss of red blood cells in patients with ANH was less than that in the control group. The postoperative inflammation, renal function, liver function and cardiac function in the ANH group were better than those in the control group, and no significant difference was noted in biochemical ions and nutritional status indicators. This paper shows that ANH not only can replace allogeneic transfusion in TKA, especially in patients with anaemia, but also has lower inflammatory indicators than allogeneic transfusion. From a security perspective, the body's tolerance to ANH is within the body's compensation range.

Hypervolemia suppresses dilutional anaemic injury in a rat model of haemodilution.

Background and Objectives: Haemodilution leads to complications in clinical practice. It is exactly unknown whether this damage is caused by the fluid or by the stretching of the vascular bed. We aimed to compare two different haemodilution techniques at the same anaemic level. Methods: Normovolemic or hypervolemic haemodilution was performed on twelve adult male Wistar rats. In the normovolemic procedure, blood was withdrawn and instantaneously administered with similar amounts of 6% hydroxyethyl starch (HES 130/0.4). Fluid was administered without withdrawing blood in the hypervolemic procedure. In both models, a 25% haematocrit level was targeted and kept at this level for 90 min to deepen the anaemia effect. Besides haemodynamics measurement, renal function (creatinine, blood urea nitrogen) and injury (tissue norepinephrine, malondialdehyde) were evaluated. Also, systemic hypoxia (lactate), oxidative stress (malondialdehyde, ischaemia-modified albumin), inflammation (tumour necrosis factor-alpha [TNF-α]), osmotic stress, adrenal stress (norepinephrine, epinephrine), and vascular stretching (atrial natriuretic peptide [ANP]) were assessed. Results: Arterial pressure in the normovolemic group was lower than in the hypervolemic group. Serum creatinine, blood urea nitrogen, and lactate levels were higher in the normovolemic group. Tissue norepinephrine and malondialdehyde levels were higher in the normovolemic group. Serum ANP, malondialdehyde, ischaemia-modified albumin, free haemoglobin, syndecan-1, and TNF-α were higher in both groups compared to respective baseline. Conclusions: Normovolemic haemodilution may lead to hypoxic kidney injury. The hypervolemic state may be advantageous if fluid is to be administered. Thus, the effect of the fluid itself can be relatively masked.

Changes in colloid oncotic pressure during cardiac surgery with different prime fluid strategies.

OBJECTIVE: In cardiac surgery, colloid oncotic pressure (COP) is affected by haemodilution that results from composition and volume of prime fluid of cardiopulmonary bypass (CPB). However, the extent to which different priming strategies alter COP is largely unknown. Therefore, we investigated the effect of different priming strategies on COP in on-pump cardiac surgery. METHODS: Patients (n = 60) were divided into 3 groups (n = 20 each), based on the center in which they were operated and the specific prime fluid strategy used in that center during the inclusion period. CPB prime fluids were either gelofusine-, albumin-, or crystalloid based, the latter two with or without retrograde autologous priming. RESULTS: In all groups, COP was lowest after weaning from CPB and one hour after CPB. Between groups, COP was lowest with gelofusine prime fluid (16.4, 16.8 mmHg, respectively) compared with crystalloids (MD: -1.9; 95% CI:-3.6, -0.2; p = .02 and MD: -2.4, 95% CI: -4.2, -0.7; p = .002) and albumin (MD: -1.8, 95% CI: -3.5, -0.50; p = .041 and MD: -2.4, 95% CI: -4.1, -0.7; p = .002). In all groups, the decrease in COP one hour after bypass compared to baseline correlated positively with fluid balance at the end of surgery (p < .001). CONCLUSIONS: COP significantly decrease during CPB surgery with the largest decrease in COP at the end of surgery, while at the same time fluid balance increases. We suggest that prime fluid strategy should be carefully selected when maintenance of COP during cardiac surgery is desirable.

Haematic antegrade repriming to enhance recovery after cardiac surgery from the perfusionist side.

Background: New era of cardiac surgery aims to provide an enhanced postoperative recovery through the implementation of every step of the process. Thus, perfusion strategy should adopt evidence-based measures to reduce the impact of cardiopulmonary bypass (CPB). Hematic Antegrade Repriming (HAR) provides a standardized procedure combining several measures to reduce haemodilutional priming to 300 mL. Once the safety of the procedure in terms of embolic release has been proven, the evaluation of its beneficial effects in terms of transfusion and ICU stay should be assessed to determine if could be considered for inclusion in Enhanced Recovery After Cardiac Surgery (ERACS) programs. Methods: Two retrospective and non-randomized cohorts of high-risk patients, with similar characteristics, were assessed with a propensity score matching model. The treatment group (HG) (n = 225) received the HAR. A historical cohort, exposed to conventional priming with 1350 mL of crystalloid confirmed the control group (CG) (n = 210). Results: Exposure to any transfusion was lower in treated (66.75% vs. 6.88%, p < 0.01). Prolonged mechanical ventilation (>10 h) (26.51% vs. 12.62%; p < 0.01) and extended ICU stay (>2 d) (47.47% vs. 31.19%; p < 0.01) were fewer for treated. HAR did not increase early morbidity and mortality. Related savings varied from 581 to 2741.94 $/patient, depending on if direct or global expenses were considered. Discussion: By reducing the gaseous and crystalloid emboli during CPB initiation, HAR seems to have a beneficial impact on recovery and reduces the overall transfusion until discharge, leading to significant cost savings per process. Due to the preliminary and retrospective nature of the research and its limitations, our findings should be validated by future prospective and randomized studies.

Blood volume estimation in cardiac surgery - A comparative analysis.

INTRODUCTION: This paper seeks to identify which of three published formulas used for estimating the blood volume of normal human subjects correlates most closely with blood volumes measured in a published study where erythrocyte volume was determined by a method using 51Cr and a nonradioactive dye was used to determine the plasma volume. METHODS: Blood volumes predicted by three published algorithms were compared with blood volume estimates from a study by Retzlaff et al. using the two-tailed Wilcoxon signed rank test and a robust version of the Bland-Altman test. RESULTS: When applied to a sample of normal subjects selected from Mayo Clinic personnel and patients, the Nadler formula correlated more closely with blood volume measured using a radio nucleotide technique than did the Allen formula or one based on a saline haemodilution technique. CONCLUSIONS: The Nadler formula correlated more closely with blood volume measurements derived from Retzlaff's study than the other formulas for estimating blood volume in a population with height and weight distribution more consistent with that seen in North America. It should be used in preference to the Allen formula for estimating blood volume in adult patients currently undergoing cardiac surgical procedures. Saline haemodilution techniques used to measure blood volume require validation against more recently developed nuclear medicine techniques using statistical methods other than regression analysis. Until validated, they should be used with caution for estimating blood volume in adult patients currently undergoing cardiac surgical procedures. If a formula using height, weight and sex is used to estimate blood volume in the context of cardiac surgery, then it must be derived using a much more comprehensive sample of the population to which it is applied than has occurred to date. In particular, it should include broader distributions of height, weight and the presence or absence and type of significant valvular disease.

Recovery of organ-specific tissue oxygen delivery at restrictive transfusion thresholds after fluid treatment in ovine haemorrhagic shock.

BACKGROUND: Fluid resuscitation is the standard treatment to restore circulating blood volume and pressure after massive haemorrhage and shock. Packed red blood cells (PRBC) are transfused to restore haemoglobin levels. Restoration of microcirculatory flow and tissue oxygen delivery is critical for organ and patient survival, but these parameters are infrequently measured. Patient Blood Management is a multidisciplinary approach to manage and conserve a patient's own blood, directing treatment options based on broad clinical assessment beyond haemoglobin alone, for which tissue perfusion and oxygenation could be useful. Our aim was to assess utility of non-invasive tissue-specific measures to compare PRBC transfusion with novel crystalloid treatments for haemorrhagic shock. METHODS: A model of severe haemorrhagic shock was developed in an intensive care setting, with controlled haemorrhage in sheep according to pressure (mean arterial pressure 30-40 mmHg) and oxygen debt (lactate > 4 mM) targets. We compared PRBC transfusion to fluid resuscitation with either PlasmaLyte or a novel crystalloid. Efficacy was assessed according to recovery of haemodynamic parameters and non-invasive measures of sublingual microcirculatory flow, regional tissue oxygen saturation, repayment of oxygen debt (arterial lactate), and a panel of inflammatory and organ function markers. Invasive measurements of tissue perfusion, oxygen tension and lactate levels were performed in brain, kidney, liver, and skeletal muscle. Outcomes were assessed during 4 h treatment and post-mortem, and analysed by one- and two-way ANOVA. RESULTS: Each treatment restored haemodynamic and tissue oxygen delivery parameters equivalently (p > 0.05), despite haemodilution after crystalloid infusion to haemoglobin concentrations below 70 g/L (p < 0.001). Recovery of vital organ-specific perfusion and oxygen tension commenced shortly before non-invasive measures improved. Lactate declined in all tissues and correlated with arterial lactate levels (p < 0.0001). The novel crystalloid supported rapid peripheral vasodilation (p = 0.014) and tended to achieve tissue oxygen delivery targets earlier. PRBC supported earlier renal oxygen delivery (p = 0.012) but delayed peripheral perfusion (p = 0.034). CONCLUSIONS: Crystalloids supported vital organ oxygen delivery after massive haemorrhage, despite haemodilution to < 70 g/L, confirming that restrictive transfusion thresholds are appropriate to support oxygen delivery. Non-invasive tissue perfusion and oximetry technologies merit further clinical appraisal to guide treatment for massive haemorrhage in the context of Patient Blood Management.

Clinical Outcomes and Medical Costs of Hydration Therapy with Hydroxyethyl Starch (130/0.4) or Acute Single Infarction.

OBJECTIVES: To investigate the effects of hydration with or without Hydroxyethyl Starch (HES) 130/0.4 on neurological outcomes and medical costs during hospitalisation in patients with a single infarction (SI) in the posterior lenticulostriate artery (LSA) territory. MATERIALS AND METHODS: In this retrospective, single-centre, non-blinded cohort study, SI in the posterior LSA was defined as an ischaemic lesion with a high-signal intensity area ≥20 mm. All patients received basic stroke care within 48 h of symptom onset between April 2015 and January 2019. Patients were divided into the following two groups by clinician's preference: 1) those administered HES 130/0.4 and 2) those receiving other infusion fluid. The relationships between hospital costs and hydration therapy type were examined. RESULTS: Eighteen (31%) of 58 patients received HES 130/0.4. The HES group had a significantly lower total cost than the control group (3.6 vs. 6.4 million yen, p=0.006). Moreover, the HES group had a significantly shorter hospital stay duration (79.5 vs. 141.0 days) and lower National Institutes of Health Stroke Scale score on day 7. Multivariate analysis found that HES 130/0.4 administration was an independent factor associated with high costs. CONCLUSIONS: Hydration therapy with HES 130/0.4 significantly decreased the total costs and hospitalisation duration of patients with SI in the posterior LSA territory.

Time course of red cell volume and plasma volume over six months in compensated chronic heart failure.

BACKGROUND: In patients with chronic heart failure (CHF), volume overload is usually described as an expansion of plasma volume (PV). Additional red cell volume (RCV) expansion also occurs in a relevant fraction of compensated CHF patients. So far, little is known about the stability of these vascular volumes and possible volume excess in compensated CHF patients over time. METHODS AND RESULTS: This study aims at quantification of blood volume and its components, RCV and PV (raw values and adjusted for sex and anthropometric characteristics, expressed as per cent of the expected normal value), using an abbreviated carbon monoxide (CO) rebreathing method (aCORM) in 14 patients (two women) with systolic CHF at baseline and at a follow-up visit after approximately 6 months. While a vast heterogeneity was observed concerning RCV (82% to 134% of normalized alues) and PV (72% to 131% of normalized values), the vascular volumes showed a mean change of 1.2% and -1.3% after a mean follow-up of 183 days. CONCLUSIONS: The vascular volumes including individual volume excess appear to be stable in compensated CHF patients. The reason for this individual volume response concerning both RCV and PV in CHF remains unclear and deserves further clarification.

The efficacy and safety of intraoperative acute normovolaemic haemodilution in complex spine surgery in a private surgical facility in Ghana.

Objectives: To assess the safety and clinical benefits of intraoperative acute normovolaemic haemodilution (ANH) in complex spine surgery. Design: Prospective comparative cohort study. Setting: A private orthopaedic hospital in Ghana. Patients: Seventy-six patients who underwent complex spine deformity surgery. Interventions: Patients were randomly assigned to two groups. 45 patients to the acute normovolaemic haemodilution (ANH) or Group 1 and 31patients to the non-ANH or Group 2. Following anesthetic administration and before incision, autologous blood was collected from patients in Group1 and was reinfused during/shortly after surgery while patients in Group2 were transfused with compatible allogeneic blood intraoperatively. Main Outcome Measures: Changes in haemodynamic parameters and incidence of allogeneic transfusions and related complications. Results: The mean age (years), gender ratio, deformity size and aetiology, fusion levels, and operative times were similar in both groups. Blood loss (ml) of patients in groups 1 and 2 were 1583ml± 830.48 vs 1623ml ± 681.34, p=0.82, respectively. The rate of allogeneic blood transfusion in groups 1 and 2 were 71% vs 80.65%, p=0.88, respectively. Haemoglobin levels (g/dL) in groups 1 and 2 were comparable in both groups at Post-operative Day (POD) 0 and POD 1. Incidence of minor allogeneic transfusion reaction was 1/45 vs 1/31, p=0.80, group-1 and group-2, respectively. Conclusion: Acute normovolaemic haemodilution can be safely performed in complex spine surgery in underserved regions. However, its use does not obviate allogeneic transfusion in patients with complex spine deformities in whom large volumes of blood loss is expected. Funding: None declared.

Adult cardiopulmonary bypass in Australian and New Zealand public hospitals: A survey of practice.

A telephone survey of cardiac anaesthetists and perfusionists at the 29 public hospitals providing adult cardiac surgical services in Australia and New Zealand was carried out between December 2019 and January 2020. The aim was to investigate current practice with regard to selected contentious elements of anaesthetic and perfusion management during cardiopulmonary bypass; primarily relating to bypass circuit priming, blood conservation methods and point-of-care coagulation testing. There was a 100% response rate. The average number of adult public cardiopulmonary bypass cases per hospital was 508 (160-1400). For cardiopulmonary bypass cases, ten hospitals (34%) routinely used a cell saver and the remainder used a cell saver selectively. Residual blood remaining in the cardiopulmonary bypass circuit was processed using a cell saver routinely in four hospitals (14%) and selectively in 23 (79%). Acute normovolaemic haemodilution was rarely used. Retrograde autologous priming was used routinely in seven hospitals (24%) and selectively in 16 (55%). All hospitals had access to point-of-care coagulation testing. The majority of hospitals targeted an activated clotting time of 480 s (range 400-500 s) prior to commencing cardiopulmonary bypass. There was marked geographic variation in access to fibrinogen concentrate. The cardiopulmonary bypass circuit prime solution was primarily a balanced crystalloid in most hospitals; however, there was significant variation regarding the addition of human albumin, mannitol, sodium bicarbonate and other medications. Many of the interventions examined were used on a case-by-case basis. These findings support the need for further research to define more evidence-based practice of these interventions.

The impact of cardiopulmonary bypass management on outcome: a propensity matched comparison between minimally invasive and conventional valve surgery.

OBJECTIVES: Research concerning cardiopulmonary bypass (CPB) management during minimally invasive cardiac surgery (MICS) is scarce. We investigated the effect of CPB parameters such as pump flow, haemoglobin concentration and oxygen delivery on clinical outcome and renal function in a propensity matched comparison between MICS and median sternotomy (MS) for atrioventricular valve surgery. METHODS: A total of 356 patients undergoing MICS or MS for atrioventricular valve surgery between 2006 and 2017 were analysed retrospectively. Propensity score analysis matched 90 patients in the MS group with 143 in the MICS group. Logistic regression analysis was performed to investigate independent predictors of cardiac surgery-associated acute kidney injury in patients having MICS. RESULTS: In MICS, CPB (142.9 ± 39.4 vs 101.0 ± 38.3 min; P < 0.001) and aortic cross-clamp duration (89.9 ± 30.6 vs 63.5 ± 23.0 min; P < 0.001) were significantly prolonged although no differences in clinical outcomes were detected. The pump flow index was lower [2.2 ± 0.2 vs 2.4 ± 0.1 l⋅(min⋅m2)-1; P < 0.001] whereas intraoperative haemoglobin levels were higher (9.25 ± 1.1 vs 8.8 ± 1.2; P = 0.004) and the nadir oxygen delivery was lower [260.8 ± 43.5 vs 273.7 ± 43.7 ml⋅(min⋅m2)-1; P = 0.029] during MICS. Regression analysis revealed that the nadir haemoglobin concentration during CPB was the sole independent predictor of cardiac surgery-associated acute kidney injury (odds ratio 0.67, 95% confidence interval 0.46-0.96; P = 0.029) in MICS but not in MS. CONCLUSIONS: Specific cannulation-related issues lead to CPB management during MICS being confronted with flow restrictions because an average pump flow index ≤2.2 l/min/m2 is achieved in 40% of patients who have MICS compared to those who have a conventional MS. This study showed that increasing the haemoglobin level might be helpful to reduce the incidence of cardiac surgery-associated acute kidney injury after minimally invasive mitral valve surgery.

Factors associated with blood cord unit bankability: an analysis of a 15-year-long case series.

Blood banking is a long and complex process requiring an accurate screening of potential donors and high-quality control systems. Previous studies in literature investigated factors potentially determining a higher cell levels with the aim of optimizing donors' selection and improving banking process. This study aims to identify factors associated with the concentration of stem cells in umbilical cord blood, so increasing the probability of bankability, focusing on the possible implications in terms of obstetric and resources management. This is a retrospective study conducted in the Obstetric Units of two Italian Hospitals in Montebelluna and Castelfranco Veneto. Study has been conducted on cord blood units banked between 1999 and 2015. Data on medical histories and clinical characteristics of mother and baby have been retrieved via a retrospective examination of medical records. A total of 869 cord blood units were studied. At multivariable analysis, in agreement with literature, birthweight and placental weight have been found to be associated with higher concentration of total nucleated cells. As additional factor, amount of fluid infused was associated with cord blood units' count. This study is the first one to clearly identify the role of fluid infusion on cord blood units' counts in addition to placental weight and delivery. Some non-modifiable features can help in predicting bankability from pre-natal aspects to factors more related with obstetric management is suggested.

Clinical implications of the blood urea nitrogen/creatinine ratio in heart failure and their association with haemoconcentration.

AIMS: The blood urea nitrogen (BUN)/creatinine ratio is a strong prognostic indicator in patients with acute decompensated heart failure (ADHF). However, the clinical impact of a high BUN/creatinine ratio at discharge with respect to renal dysfunction, neurohormonal hyperactivity, and different responsiveness to decongestion therapy remains unclear. Herein, we examined (i) the predictive value of a high BUN/creatinine ratio at discharge and (ii) its haemoconcentration-dependent effects, in patients with ADHF. METHODS AND RESULTS: The West Tokyo Heart Failure registry was a multicentre, prospective cohort registry-based study that enrolled patients hospitalized with a diagnosis of ADHF. The endpoint was post-discharge all-cause death. Based on the degree of haemoconcentration, patients (n = 2090) were divided into four subcategories. In multivariate proportional hazard analyses, a higher BUN/creatinine ratio was independently associated with higher all-cause mortality in the total population and in the extreme haemodilution (ΔHaemoglobin ≤ -0.9 g/dL) and haemoconcentration (0.8 g/dL ≤ ΔHaemoglobin) subcategories, but not in the modest haemodilution/haemoconcentration subcategories. CONCLUSIONS: A higher BUN/creatinine ratio at discharge was independently associated with higher post-discharge all-cause mortality in patients with ADHF. The predictive value of a high BUN/creatinine ratio at discharge was haemoconcentration dependent and may be an unfavourable predictor in patients showing excessive haemoconcentration and haemodilution, but not in those showing modest haemoconcentration/haemodilution.

UBC-Nepal Expedition: Haemoconcentration underlies the reductions in cerebral blood flow observed during acclimatization to high altitude.

NEW FINDINGS: What is the central question of this study? The aim was to evaluate the degree to which increases in haematocrit alter cerebral blood flow and cerebral oxygen delivery during acclimatization to high altitude. What is the main finding and its importance? Through haemodilution, we determined that, after 1 week of acclimatization, the primary mechanism contributing to the cerebral blood flow response during acclimatization is an increase in haemoglobin and haematocrit. The remaining contribution to the cerebral blood flow response during acclimatization is likely to be attributable to ventilatory acclimatization. ABSTRACT: At high altitude, an increase in haematocrit (Hct) is achieved through altitude-induced diuresis and erythropoiesis, both of which result in increased arterial oxygen content. Given the impact of alterations in Hct on oxygen content, haemoconcentration has been hypothesized to mediate, in part, the attenuation of the initial elevation in cerebral blood flow (CBF) at high altitude. To test this hypothesis, healthy men (n = 13) ascended to 5050 m over 9 days without the aid of prophylactic acclimatization medications. After 1 week of acclimatization at 5050 m, participants were haemodiluted by rapid saline infusion (2.10 ± 0.28 l) to return Hct towards pre-acclimatization values. Arterial blood gases, Hct, global CBF (duplex ultrasound) and haemodynamic variables were measured after initial arrival at 5050 m and after 1 week of acclimatization at high altitude, before and after the haemodilution protocol. After 1 week at 5050 m, the Hct increased from 42.5 ± 2.5 to 49.6 ± 2.5% (P < 0.001), and it was subsequently reduced to 45.6 ± 2.3% (P < 0.001) after haemodilution. Global CBF decreased from 844 ± 160 to 619 ± 136 ml min-1 (P = 0.033) after 1 week of acclimatization and increased to 714 ± 204 ml min -1 (P = 0.045) after haemodilution. Despite the significant changes in Hct, and thus oxygen content, cerebral oxygen delivery was unchanged at all time points. Furthermore, these observations occurred in the absence of any changes in mean arterial blood pressure, cardiac output, arterial blood pH or oxygen saturation pre- and posthaemodilution. These data highlight the influence of Hct in the regulation of CBF and are the first to demonstrate experimentally that haemoconcentration contributes to the reduction in CBF during acclimatization to altitude.