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Introduction: Management of acute myocardial infarction (MI) mandates careful optimization of volemia, which can be challenging due to the inherent risk of congestion. Increased myocardial compliance in response to stretching, known as stretch-induced compliance (SIC), has been recently characterized and partly ascribed to cGMP/cGMP-dependent protein kinase (PKG)-related pathways. We hypothesized that SIC would be impaired in MI but restored by activation of PKG, thereby enabling a better response to volume loading in MI. Methods: We conducted experiments in ex vivo rabbit right ventricular papillary muscles under ischemic and non-ischemic conditions as well as pressure--volume hemodynamic evaluations in experimental in vivo MI induced by left anterior descending artery ligation in rats. Results: Acutely stretching muscles ex vivo yielded increased compliance over the next 15 min, but not under ischemic conditions. PKG agonists, but not PKC agonists, were able to partially restore SIC in ischemic muscles. A similar effect was observed with phosphodiesterase-5 inhibitor (PDE5i) sildenafil, which was amplified by joint B-type natriuretic peptide or nitric oxide donor administration. In vivo translation revealed that volume loading after MI only increased cardiac output in rats infused with PDE5i. Contrarily to vehicle, sildenafil-treated rats showed a clear increase in myocardial compliance upon volume loading. Discussion: Our results suggest that ischemia impairs the adaptive myocardial response to acute stretching and that this may be partly prevented by pharmacological manipulation of the cGMP/PKG pathway, namely, with PDE5i. Further studies are warranted to further elucidate the potential of this intervention in the clinical setting of acute myocardial ischemia. [ABSTRACT FROM AUTHOR]

Introduction: Management of acute myocardial infarction (MI) mandates careful optimization of volemia, which can be challenging due to the inherent risk of congestion. Increased myocardial compliance in response to stretching, known as stretch-induced compliance (SIC), has been recently characterized and partly ascribed to cGMP/cGMP-dependent protein kinase (PKG)-related pathways. We hypothesized that SIC would be impaired in MI but restored by activation of PKG, thereby enabling a better response to volume loading in MI.Methods: We conducted experiments in ex vivo rabbit right ventricular papillary muscles under ischemic and non-ischemic conditions as well as pressure–volume hemodynamic evaluations in experimental in vivo MI induced by left anterior descending artery ligation in rats.Results: Acutely stretching muscles ex vivo yielded increased compliance over the next 15 min, but not under ischemic conditions. PKG agonists, but not PKC agonists, were able to partially restore SIC in ischemic muscles. A similar effect was observed with phosphodiesterase-5 inhibitor (PDE5i) sildenafil, which was amplified by joint B-type natriuretic peptide or nitric oxide donor administration. In vivo translation revealed that volume loading after MI only increased cardiac output in rats infused with PDE5i. Contrarily to vehicle, sildenafil-treated rats showed a clear increase in myocardial compliance upon volume loading.Discussion: Our results suggest that ischemia impairs the adaptive myocardial response to acute stretching and that this may be partly prevented by pharmacological manipulation of the cGMP/PKG pathway, namely, with PDE5i. Further studies are warranted to further elucidate the potential of this intervention in the clinical setting of acute myocardial ischemia.

Background: In patients undergoing left atrial appendage (LAA) closure, an accurate sizing of the LAA is key to optimize device sizing, procedural success and reduce complications. Previous studies have shown that intraprocedural volume loading increases LAA dimensions and improves device sizing. However, the safety and effects on LAA and device sizing of administering a fluid bolus during pre-procedural transesophageal echocardiography (TEE) are unknown. The aim of this study was to determine the safety and impact on LAA dimensions and device sizing of an intravenous (IV) fluid bolus administered during TEE in the setting of the pre-procedural work-up for LAA closure.Methods: The study included a total of 72 patients who underwent TEE to assess suitability for LAAC and received a 500 ml IV bolus of normal saline. The LAA landing zone (LZ) and depth were measured by TEE before and after volume loading, and these measurements were used to predict the device size implanted during a subsequent percutaneous LAAC procedure.Results: There were no complications associated with volume loading. The baseline mean LZ was 19.6 ± 3.6 mm at 90o, and 20.2 ± 4.1 mm at 135o. Following fluid bolus, the maximum diameter increased 1.5 ± 1.0 mm at 90o (p<0.001), and 1.3 ± 1.0 mm at 135o (p<0.001). The baseline mean depth of the LAA was 26.5 ± 5.5 mm at 90o, and 23.9 ± 5.8 mm at 135o. After fluid bolus, the mean depth increased by 1.5 ± 1.8 mm (p<0.001) and 1.6 ± 2.0 (p<0.001), at 90o and 135o, respectively. Sizing based on post-bolus measurements of the LZ significantly improved the agreement with the final device size selection during the procedure in 71.0% of cases (vs. 42.0% with pre-bolus measurements).Conclusions: Volume loading during ambulatory TEE as part of the pre-procedural work-up of LAAC is safe and significantly increases LAA dimensions. This strategy may become the new standard, particularly in centers performing LAAC with no TEE guidance, as it improves LAA sizing and more accurately predicts the final device size. [ABSTRACT FROM AUTHOR]

Background: The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool., Methods: PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried., Results: A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions., Conclusions: Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

Abstract Background Swift and adequate fluid loading is a cornerstone of septic shock therapy. Yet, careful assessment of volume responsiveness and volume amount during the resuscitation process is a prerequisite. Both overzealous initial fluid administration and late fluid overload are harmful and may be associated with increased mortality. Main body Static (i.e., central venous or pulmonary artery occlusion) pressure readings are erroneous for monitoring fluid resuscitation and should be abandoned. Dynamic measurements (i.e., stroke volume and pulse pressure variation) better predict fluid responsiveness than static filling pressures but the conditions necessary for these parameters to correctly evaluate preload dependency are frequently not met. The passive leg raising maneuver as a means to alter biventricular preload in combination with real-time measurement of cardiac output changes is an easy-to-use, fast, relatively unbiased, and accurate bedside test to guide fluid management and to avoid fluid overload during early septic shock treatment. Moreover, PLR may also be particularly useful to assist various treatments that trigger fluid removal during the “de-resuscitation” phase of septic shock. Conclusions The passive leg raising maneuver in combination with real-time measurement of cardiac output changes is an easy-to-use, fast, relatively unbiased, and accurate bedside test to guide fluid management during septic shock.

Purpose: to justify ratio means general physical training and special physical trainingin the annual cycle of training university students who train in sports sections swimming. Material and Methods: the study involved students G. S. Skovoroda HNPU aged 16–17 years, who were involved in the sport of swimming section. In the paper we used the following methods: analysis of scientific and methodological literature, teaching observations, educational testing, pedagogical experiment; methods of mathematical statistics. Results: by volume of training loads and improved ratio means general physical training and special physical training at different stages of the annual cycle of training university students who train in sports sections swimming. Conclusions: rational relationship means general and special physical training allows you to find the most effective ways of improving the process of preparing students fins and helps to improve the absolute athletic performance.

Purpose : to study the dynamics of the special performance and volume of training load during annual training swimmers. Material / Methods : The study involved 14 teams of students of Kharkiv universities. All swimmers are of high qualification. Motor tests of special performance swimmers, functional tests were used to confirm the effectiveness of the training process. Results : The dynamics of special performance indicators and volume of training load of highly qualified swimmers in the annual cycle of training. Determined part of aerobic (58.3 %), aerobic- anaerobic special (34.5%), anaerobic- glycolytic (5.5%), anaerobic- alactate (1.7%) loadings in the direction of total training load for the academic year. Conclusions : In preparing swimmers stayer is the most appropriate single-cycle construction of the annual cycle, and for swimmers, sprinters should be based on two-cycle version of the load distribution.

Volume loading increases left ventricular (LV) stroke volume (LVSV) through series interaction, but may paradoxically reduce LVSV in the presence of large increases in right ventricular (RV) afterload because of direct ventricular interaction (DVI). RV afterload is often increased in chronic obstructive pulmonary disease (COPD) as a result of pathological changes to respiratory mechanics, namely increased negative intrathoracic pressure (nITP), dynamic lung hyperinflation (DH), and increased pulmonary vascular resistance (PVR). These hallmarks of COPD negatively impact LV hemodynamics in normovolemia. However, it is unknown how these heart-lung interactions are impacted by acute volume loading. Twenty healthy subjects (23 ± 2 yr) completed the study protocol, involving acute volume loading via 20° head-down tilt (HDT) in isolation and with 1) inspiratory resistance of -20 cmH2O (HDT+nITP) and 2) nITP, expiratory resistance to induce DH and hypoxic-mediated increases in PVR (HDT+COPD model). LV volumes and geometry were assessed using triplane echocardiography. HDT significantly increased LVSV by 10 ± 10% through an 8 ± 6% increase in LV end-diastolic volume (LVEDV). HDT+nITP paradoxically decreased LVSV by 11 ± 12% and LVEDV by 6 ± 9% from supine baseline, or -14 ± 10% LVSV and -15 ± 13% LVEDV from HDT (P < 0.001). HDT+COPD model decreased LVSV (21 ± 10% and 28 ± 11%) and LVEDV (16 ± 10% and 22 ± 10%) from both supine and HDT, respectively (P < 0.001). Under all conditions, significant septal flattening (increased radius of septal curvature) occurred, indicating DVI. Thus, when RV afterload is increased and/or an external constraint to ventricular filling exists, acute volume loading appears to paradoxically reduce LVSV. These findings have important implications for understanding how volume status impacts cardiopulmonary interactions in COPD. [ABSTRACT FROM AUTHOR]

It was set and solved the closed problem of the theory of plasticity in terms of volume loading. Circularity of solution does not complicate the task, but simplifies as six equations of kinematic part of a task gives to the solution at a choice of combinations of flat functions. According to the equations of connection, such requirements of deformations are imposed to the static part of a task at determination of stress. Various solutions for the making components of a tensor of stress were obtained. Dependencies for integral characteristics of stress state of deformation point were shown. The kernel of the solution of intensity of normal stress, which characterizes the generalized point stress parameters was defined. [ABSTRACT FROM AUTHOR]

Purpose: to justify ratio means general physical training and special physical trainingin the annual cycle of training university students who train in sports sections swimming. Material and Methods: the study involved students G. S. Skovoroda HNPU aged 16-17 years, who were involved in the sport of swimming section. In the paper we used the following methods: analysis of scientific and methodological literature, teaching observations, educational testing, pedagogical experiment; methods of mathematical statistics. Results: by volume of training loads and improved ratio means general physical training and special physical training at different stages of the annual cycle of training university students who train in sports sections swimming. Conclusions: rational relationship means general and special physical training allows you to find the most effective ways of improving the process of preparing students fins and helps to improve the absolute athletic performance. [ABSTRACT FROM AUTHOR]

Background: Swift and adequate fluid loading is a cornerstone of septic shock therapy. Yet, careful assessment of volume responsiveness and volume amount during the resuscitation process is a prerequisite. Both overzealous initial fluid administration and late fluid overload are harmful and may be associated with increased mortality. Main body: Static (i.e., central venous or pulmonary artery occlusion) pressure readings are erroneous for monitoring fluid resuscitation and should be abandoned. Dynamic measurements (i.e., stroke volume and pulse pressure variation) better predict fluid responsiveness than static filling pressures but the conditions necessary for these parameters to correctly evaluate preload dependency are frequently not met. The passive leg raising maneuver as a means to alter biventricular preload in combination with real-time measurement of cardiac output changes is an easy-to-use, fast, relatively unbiased, and accurate bedside test to guide fluid management and to avoid fluid overload during early septic shock treatment. Moreover, PLR may also be particularly useful to assist various treatments that trigger fluid removal during the "de-resuscitation" phase of septic shock. Conclusions: The passive leg raising maneuver in combination with real-time measurement of cardiac output changes is an easy-to-use, fast, relatively unbiased, and accurate bedside test to guide fluid management during septic shock. [ABSTRACT FROM AUTHOR]

Background Fluid bolus administration is a standard treatment for hypotension. However, the effectiveness of the traditional prophylactic bolus in parturients undergoing spinal anesthesia for cesarean delivery has been questioned. One potential mechanism for the failure of a prophylactic fluid bolus to prevent hypotension is hypervolemia-induced destruction of the endothelial glycocalyx, a structure that plays a vital role in regulating intravascular fluid shifts. Methods Thirty healthy parturients undergoing elective cesarean delivery under spinal anesthesia were recruited. Known endothelial glycocalyx biomarkers, heparan sulfate and syndecan-1 along with atrial natriuretic peptide, were measured before and after a 750-mL crystalloid fluid bolus. Cardiac performance parameters, cardiac index and systemic vascular resistance, were monitored during the fluid bolus using thoracic-impedance cardiography. Results A significant increase in both heparan sulfate 96 ng/mg ( P =0.0098) and syndecan-1 2.4 ng/mg ( P =0.045) were observed after the fluid bolus. There was a non-significant increase in atrial natriuretic peptide 0.6 pg/mg ( P =0.293). Cardiac parameters showed a small but significant change; over an average of 15 min, cardiac index increased by 0.1 L/min/m 2 ( P =0.0005) and systemic vascular resistance decreased by 30.7 dyn.s/cm 5 ( P =0.0025). Conclusions A prophylactic fluid bolus in parturients undergoing spinal anesthesia for cesarean delivery disrupts the endothelial glycocalyx, as noted by a statistically significant increase in post-bolus heparan sulfate and syndecan-1 levels. Although studied in the past, atrial natriuretic peptide could not explain this disruption. Our fluid bolus did not have a clinically relevant effect on cardiac performance. [ABSTRACT FROM AUTHOR]

This study assessed effects of head-down-tilt (HDT) bed rest on dynamic cerebral autoregulation (CA) in 21 healthy young adults with volume loading and exercise countermeasures. Of these, seven underwent an 18-day bed rest without exercise countermeasures (sedentary group). Volume loading with dextran infusion was performed after bed rest to restore reduced plasma volume to levels before bed rest. In the other 14 subjects, supine cycling during bed rest was performed to preserve cardiac work from before bed rest (exercise group). Volume loading was also performed in a subgroup of these subjects (ExDex, n = 7). Dynamic CA was estimated by transfer function analysis of changes in arterial pressure and cerebral blood flow (CBF) velocity in the very low (VLF, 0.02-0.07 Hz), low (LF, 0.07-0.20 Hz), and high frequency ranges (HF, 0.20-0.35 Hz). After bed rest, transfer function gain was reduced in the sedentary group (VLF, 0.93 ± 0.23 to 0.61 ± 0.23 cm -1 .s -1mm Hg; P = 0.007) and in the exercise group (LF, 1.22 ± 0.43 to 0.94 ± 0.26 cm-1·s-1 mmHg; P = 0.005, HF, 1.32 ± 0.55 to 1.00 ± 0.32 cm -1 mmHg; P = 0.010). After volume loading, transfer function gain increased in the sedentary group but not in the Ex + Dex group. Taken together, these findings suggest that dynamic CA was preserved or improved after HDT bed rest in both sedentary and exercise subjects. Furthermore, increases of transfer function gain with volume loading suggest that changes in plasma volume may play an important role in CBF regulation. [ABSTRACT FROM AUTHOR]

Background—Hemodynamic assessment after volume challenge has been proposed as a way to identify heart failure with preserved ejection fraction. However, the normal hemodynamic response to a volume challenge and how age and sex affect this relationship remain unknown. Methods and Results—Sixty healthy subjects underwent right heart catheterization to measure age- and sex-related normative responses of pulmonary capillary wedge pressure and mean pulmonary arterial pressure to volume loading with rapid saline infusion (100-200 mL/min). Hemodynamic responses to saline infusion in heart failure with preserved ejection fraction (n=l1) were then compared with those of healthy young (<50 years of age) and older (≥50 years of age) subjects. In healthy subjects, pulmonary capillary wedge pressure increased from 10±2 to 16±3 mm Hg after ~1 L and to 20±3 mm Hg after ~2 L of saline infusion. Older women displayed a steeper increase in pulmonary capillary wedge pressure relative to volume infused (16±4 mmHg.L-1.m2) than the other 3 groups (P≤0.019). Saline infusion resulted in a greater increase in mean pulmonary arterial pressure relative to cardiac output in women compared with men regardless of age. Subjects with heart failure with preserved ejection fraction exhibited a steeper increase in pulmonary capillary wedge pressure relative to infused volume (25±12 mm Hg.L-1.m2) than healthy young and older subjects (P≤0.005). Conclusions—Filling pressures rise significantly with volume loading, even in healthy volunteers. Older women and patients with heart failure with preserved ejection fraction exhibit the largest increases in pulmonary capillary wedge pressure and mean pulmonary arterial pressure. [ABSTRACT FROM AUTHOR]

Background This study aims to study changes in blood volume after 1 litre infusions of Gelofusine® [4% succinylated gelatine in 0.7% saline, weight-average molecular weight (MWw) 30 kDa] and Voluven® (6% hydroxyethyl starch in 0.9% saline, MWw 130 kDa) in the presence of increased capillary permeability. Methods In this randomized double-blind study, adults undergoing laparoscopic cholecystectomy received 1 litre of Gelofusine® (n=12) or Voluven® (n=13) over 1 h at the induction of anaesthesia. No other fluids were given. Haematocrit, serum electrolytes, and osmolality were measured before infusion and hourly thereafter for 4 h. Changes in blood volume were calculated from changes in haematocrit. The urinary albumin:creatinine ratio (ACR) was measured before and after operation. Results Baseline parameters before the two infusions were similar (P>0.050). The urinary ACR increased significantly after operation after Gelofusine® (P=0.011) and Voluven® (P=0.002), indicating increased capillary permeability. Voluven® produced a greater increase in serum chloride concentration (P=0.028) and a larger decrease in strong ion difference (P=0.009) than Gelofusine®. There were no significant differences in changes in haematocrit (P=0.523) and blood volume (P=0.404) over the study period when the two infusions were compared, nor were there any differences in serum sodium, potassium, bicarbonate, and albumin concentrations (P>0.050). Urine output, sodium concentration, and osmolality were similar after the two infusions (P>0.050). Conclusions The blood volume-expanding effects of the two colloids were not significantly different, despite the increase in postoperative urinary ACR and the 100 kDa difference in MWw. [ABSTRACT FROM PUBLISHER]

The immobilized bioprocess (IBP) was investigated for the removal of organic carbon and ammonia nitrogen from wastewater. Two wastewaters (a food industry wastewater and a composite industrial wastewater) were investigated, one containing high concentration (820-1300 mg/l) and the other medium concentration (250-450 mg/l) of chemical oxygen demand (COD). Three mixed liquor suspended solids (MLSS) (3000, 5000, and 9000 mg/l) and two hydraulic retention times (HRT) (12 h and 24 h) were employed representing different surface loading and volume loading factors. IBP provides high sludge retention time (SRT), enabling improved removal of COD and ammonia nitrogen. The results showed 78-93% and 83-96% removals soluble COD (SCOD) and ammonia (NHDue to image rights restrictions, multiple line equation(s) cannot be graphically displayed.-N), respectively, from the food industry wastewater, when the surficial removal rate and volumetric removal rate in the IBP were 0.011-0.056 kg COD/m²-d and 2.3-12 kg COD/m³-d, respectively. For the composite industrial wastewater, removal of SCOD and NH-N were 53-80% and 38-69%, respectively, when the surficial removal rate and volumetric removal rate were 0.0048-0.016 kg COD/m²-d and 1.0-3.4 kg COD/m3-d, respectively. The results further show stable removals of COD and NH-N, albeit decreasing with decreasing HRTs and MLSS. IBP facilitates simple operation and good effluent quality without requiring sludge recycling. [ABSTRACT FROM AUTHOR]

The article presents a study on the physiological effect of 1-liter intravenous infusion of 0.9% saline, 4% succinylated gelatine (Gelofusine), and 6% hydroxyethyl starch (Voluven) on blood volume and endocrine responses of healthy volunteers. It says that hematological, biochemical and hormonal analyses were performed to 10 male volunteers. Results of the study indicate that excretion of fluid containing sodium and chloride may depend on the suppression of renin-angiotensin-aldosterone system.

Abstract: Objective: Assessment of haemodynamic, respiratory and renal effects of hypertonic saline–hydroxyethyl starch (HyperHES®) in critically ill-patients with hemorrhagic shock. Patients and methods: Seventeen mechanically ventilated patients with hemorragic shock benefiting from a cardiovascular monitoring by PiCCO device and requiring rapid volume loading. Two hundred and fifty milliliters of HyperHES® were given over 5minutes. The efficacy of volume loading was assessed by the measure of the systolic arterial pressure (SAP), cardiac index (CI), stroke volume variation (SVV) and the indexed systemic vascular resistance (iSVR). Studied parameters were assessed at baseline, 5, 30, 60 and 180minutes after the end of HyperHES® infusion. Results: SAP (105±23 vs 77±10; p <0.001) and CI (4.8±1.1 vs 3.5±0.9; p <0.001) were significantly increased whereas iSVR (1175±310 vs 1501±337; p <0.01) and SVV (13±7 vs 20±5; p <0.01) were significantly decreased 5minutes after the HyperHES® infusion. Sodium (145±6 vs 136±5; p <0.001) and chloride (118±7 vs 107±6; p <0.001) were increased 5minutes after the infusion. The PaO2/FiO2 ratio as the extravascular lung water was not influenced by the infusion. The follow-up of renal parameters during the three first days (creatinemia, uremia and diuresis) did not revelead significant variations. Conclusion: In patients with hemorrhagic shock, the infusion of hypertonic saline (7.5%) hydroxyethyl starch association was followed by an increase in SAP, CI serum sodium and chloride concentrations. Study design: Prospective observational study. [Copyright &y& Elsevier]

Abstract: In order to address the possible role of blood acid–base status in controlling the rectal gland, dogfish were fitted with indwelling arterial catheters for blood sampling and rectal gland catheters for secretion collection. In intact, unanaesthetized animals, isosmotic volume loading with 500mmolL−1 NaCl at a rate of 15mLkg−1 h−1 produced a brisk, stable rectal gland secretion flow of about 4mLkg−1 h−1. Secretion composition (500mmolL−1 Na+ and Cl−; 5mmolL−1 K+; <1mmolL−1 Ca2+, Mg2+, SO4 2−, or phosphate) was almost identical to that of the infusate with a pH of about 7.2, HCO3 − mmolL−1 <1mmolL−1 and a (1Torr) close to . Experimental treatments superimposed on the infusion caused the expected disturbances in systemic acid–base status: respiratory acidosis by exposure to high environmental , metabolic acidosis by infusion of HCl, and metabolic alkalosis by infusion of NaHCO3. Secretion flow decreased markedly with acidosis and increased with alkalosis, in a linear relationship with extracellular pH. Secretion composition did not change, apart from alterations in its acid–base status, and made negligible contribution to overall acid–base balance. An adaptive control of rectal gland secretion by systemic acid–base status is postulated—stimulation by the “alkaline tide” accompanying the volume load of feeding and inhibition by the metabolic acidosis accompanying the volume contraction of exercise. [Copyright &y& Elsevier]

Arterial and venous pressures were measured in hagfishes subjected to acute changes in salinity. The osmotic pressure of the seawater (SW) was increased or decreased by approximately 10%. Sixty minutes after the change in medium osmolarity the osmotic pressure of the blood corresponded with that of the medium. Following transfer to 90% SW all measured parameters changed as predicted for a passive increase in blood volume, apart from the pressure in the posterior cardinal vein (PCV) which fell. By 2 h dorsal aortic (DA) pressure and pressure in the PCV and supraintestinal vein had returned to pre-change values. In contrast, following exposure to 110% SW, pressures fell and apart from the supraintestinal vein they remained low at 120 min. At 24 h, DA pressure was lower than pre-change values for both groups. The data are consistent with the concept of central venous tone being regulated in hagfishes, which cope better with volume expansion than volume depletion. [ABSTRACT FROM AUTHOR]

Plasma catecholamines were measured following surgery under anaesthesia and after exposing hagfish to 90 and 110% sea water (SW). Plasma noradrenaline (NA) concentration increased from a resting value of 7 to 818 nM l−1 on anaesthesia. Plasma adrenaline (AD) did not change. NA concentrations also increased during volume depletion (110% SW), but to much lower values (26 nM l−1 at 100 min). AD concentrations were increased at 20 min, then fell. During volume loading (90% SW) NA fell, and AD increased to a maximum concentration of 511 nM l−1 at 40 min (resting concentration 24 nM l−1). The data are consistent with a vasoconstrictory role for NA on central veins when venous pressures fall and a vasodilatory role for AD on volume expansion. [ABSTRACT FROM AUTHOR]

Aims: This study was designed to test if the renal excretion of the N-terminal prohormone of the B-type natriuretic peptide (NTproBNP) is modulated by angiotensin-converting enzyme inhibition (ACE-I). Methods: Following 7 days on a sodium-enriched diet and an induction period of 4 days with incremental dosages of enalapril (2.5, 5, 7.5, 10 mg) or placebo, 10 healthy subjects underwent crossover and double-blind treatment with 20 mg enalapril sodium or placebo at 8:00 h. After 4 h (at 12:00 h), 20 ml·kg–1 NaCl 0.9% was infused over 60 min. Hemodynamics were determined and blood and urine were sampled at 8:00, 12:00, 13:00, 14:00, 16:00, and 18:00 h. Angiotensin II (AII), NTproANP, and NTproBNP were determined by radio- and electrochemiluminescence immunoassays. Results: In the whole group, ACE-I led to a lower arterial blood pressure during the fourth day of induction and during the time from 8:00 to 16:00 h, a decrease in AII levels from 8:00 to 14:00 h (p < 0.05), and to a higher cumulative urine output (p < 0.05) in comparison with control. Neither cumulative sodium nor urinary NTproBNP/creatinine excretion were significantly increased after ACE-I. However, a subgroup of 6 volunteers – showing an increase in sodium excretion after ACE-I – also demonstrated lower AII levels at 13:00 h, a higher cumulative urine flow, and a higher urinary NTproBNP/creatinine excretion in comparison with control (all: p < 0.05). Conclusions: This suggests that the renal excretion of NTproBNP is modified by enalapril. However, it remains to be determined if this is a direct effect of ACE-I, the decrease in arterial blood pressure, or other potentially confounding variables like bradykinin or endopeptidase activity. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: The role of the Frank–Starling mechanism in the regulation of cardiac systolic function in the ischemic failing heart was examined in conscious dogs. Left ventricular (LV) dimension, pressure and systolic function were assessed using surgically implanted instrumentations and non-invasive echocardiogram. Heart failure was induced by daily intra-coronary injections of microspheres for 3–4 weeks via implanted coronary catheters. Chronic coronary embolization resulted in a progressive dilation of the left ventricle (12±3%), increase in LV end-diastolic pressure (118±19%), depression of LV dP /dt max (−19±4%), fractional shortening (−36±7%), and cardiac work (−60±9%), and development of heart failure, while the LV contractile response to dobutamine was depressed. A brief inferior vena caval occlusion in dogs with heart failure decreased LV preload to match the levels attained in their control state and caused a further reduction of LV dP /dt max, fractional shortening, stroke work and cardiac work. Moreover, in response to acute volume loading, the change in the LV end-diastolic dimension–pressure (ΔLVEDD–ΔLVEDP) curve in the failing heart became steeper and shifted significantly to the left, while the increases in LV stroke work and cardiac work were blunted. Thus, our results suggest that the Frank–Starling mechanism is exhausted in heart failure and unable to further respond to increasing volume while it plays an important compensatory role in adaptation to LV dysfunction in heart failure. [Copyright &y& Elsevier]

This article cites a study investigating the hypothesis that initial distribution volume of glucose measures has a close relationship with intrathoracic blood volume during hemodynamically unstable states early after esophagectomy. Although patients with aortic aneurysm were excluded from the study, patients who had a history of diabetes mellitus and/or cardiovascular diseases such as hypertension without apparent ischemic heart disease were included into the study. Seventeen consecutive surgical patients admitted postoperatively to the general intensive care unit (ICU) from March 2003 to August 2004 were initially enrolled into the study. Postoperative measurements were made three times: immediately after admission to the ICU on the operative day, during clinically defined hypotension, and 10 minutes after completion of volume loading with 250 mL of 10% low-molecular-weight dextran over 20 to 30 minutes. The findings have not supported the hypothesis.

Objective. – Assessment of haemodynamic effects of 250 ml hypertonic saline 7.5% (HS) perfusion in critically ill patients with severe sepsis or septic shock.Study design. – Observational study.Patients. – Twelve mechanically ventilated patients with severe sepsis or septic shock requiring a pulmonary artery catheter and volume loading.Intervention. – Two hundred and fifty millilitres HS were given over 15 min. Were measured: heart rate (HR), mean arterial pressure (MAP) and pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), cardiac index (CI), indexed systemic vascular resistance (ISVR), indexed pulmonary vascular resistance (IPVR), plasma sodium, chloride, protein and haemoglobin concentrations and arterial blood lactate. Studied parameters were assessed at baseline (T0) and 5 (T0) and 105 min (T120) after the end of HS infusion.Results. – MAP, HR and RAP were not altered. HS increased PAPM (25 ± 5–30 ± 6 mmHg), PCWP (13 ± 3–18 ± 4 mmHg) and CI (3.5 ± 1.2–4.6 ± 1.1 l/min per m2) at T20 (P < 0.05). ISVR and IPVR were decreased at T20. Protein and haemoglobin were decreased at T20. Sodium and chloride were increased at T20 (from 136 ± 4 to 147 ± 4 and from 110 ± 6 to 123 ± 6 mmol/l, respectively, P < 0.01) and T120.Conclusion. – In patients with severe sepsis or septic shock, 250 ml HS transiently (<120 min) increases CI and PCWP and induces an increase in sodium and chloride concentrations. [Copyright &y& Elsevier]

A jet inner-loop bioreactor (JIBR) was used to treat synthetic sanitary sewage with low, medium and high COD load. The experimental results show that it could meet discharge standard at 20–30 min of HRT (hydraulic retention time) for low COD concentration and 60–120 min of HRT for medium and high COD concentration. The maximal COD volume loading and COD sludge loading of 27 kg·m−3·d−1 and 5 kg/d per kg MLSS were acheived respectively, that were 10–20 times higher than those of traditional wastewater treatment processes. The BOD5 removal efficiency was more than 90% and NH−N more than 85%. The study on the activity showed that the oxygen consumption rate of the activated sludge in the JIBR was 39. 13 mg·L−1·h−1, which was 1. 7 times higher than that of the SBR (Sequencing Batch Reactor) and the dominant bacteria in jet inner-loop bioreactor was Pseudomonas species. [ABSTRACT FROM AUTHOR]

: BackgroundIt is recommended that patients with impending abdominal compartment syndrome (ACS) should be volume loaded to insure the adequate preload. We evaluated our prospective resuscitation database to determine how patients who developed ACS differ from non-ACS patients in response to early volume loading.: MethodsOver 36 months, 152 consecutive high-risk patients were resuscitated by a standard intensive care unit (ICU) protocol that escalates interventions in nonresponders. Interventions, responses, and outcomes are prospectively collected and the characteristics of ACS and non-ACS patients were compared.: ResultsTwenty-three patients (15%) developed ACS and were decompressed 8 ± 1 hours after ICU admission. The ACS and non-ACS patients had similar demographics and injury severity. The severity of pre-ICU shock tended to be greater in the ACS patients. During the first 8 hours of ICU resuscitation, patients who developed ACS received more blood transfusions (11 ± 2 versus 2 ± 0.2 units; P<0.05) and crystalloids (13 ± 2 versus 4 ± 0.3 L; P<0.05). As a result, pulmonary capillary wedge pressure increased more in the ACS patients (20 ± 1.5 versus 15 ± 0.5 mm Hg; P<0.05), but comparatively the cardiac index did not (3.2 ± 0.2 versus 4.2 ± 0.1 L/min/m2; P<0.05) and the ACS patients developed pathologic elevations of gastric regional CO2 pressures (70 ± 7 versus 48 ± 1 mm Hg P<0.05).: ConclusionsConventional preload directed resuscitation to enhance cardiac function is not effective in patients with impending ACS, and this traditional resuscitation strategy is detrimental in this subgroup of patients. [Copyright &y& Elsevier]

In the mammalian heart the metabolic costs of pressure loading exceed those of volume loading. As evidence suggests that the opposite may be true in fish, we evaluated the metabolic costs of volume and pressure loading in the isolated trout heart and compared the results with the mammalian heart based on the biomechanical properties of cardiac muscle. The highest power output (2.33±0.32 mW g–1, n=5) appeared at the highest preload pressure tested (0.3 kPa) and at an afterload of 5 kPa. At a higher afterload, power did not increase because stroke volume fell. The highest mechanical efficiency (20.7±2.0%, n=5) was obtained at a preload of 0.15 kPa and an afterload of 5 kPa. Further increases in preload or afterload did not increase mechanical efficiency, probably because of increases in ventricular wall stress which increased the oxygen consumed disproportionately more than the stroke work. Under pressure unloading (25% decrease in power output), mechanical efficiency was significantly higher in comparison with volume unloading. Given that stiffness of the ventricular tissue is larger in trout than in rat papillary muscles, it is suggested that the increased strain during volume loading is energetically disadvantageous for stiff muscles like those of trout, but it is advantageous when muscle stiffness is lower as it occurs in the rat papillary muscle. [ABSTRACT FROM AUTHOR]

Volume loading tends to increase blood pressure. Resultant arterial baroreflexes, especially the heart rate component, would counteract renal compensation of volume expansion. In this study, we investigated effect of volume loading on baroreflex vagal bradycardia (BVB) induced by electrical stimulation of the aortic depressor nerves in chloralose/urethane-anesthetized, succinylcholine-immobilized, artificially ventilated rats. As a result, we confirmed that volume loading inhibits BVB. The inhibition was abolished following spinal cord transection at C2. In contrast, volume loading did not affect the bradycardia induced by electrical stimulation of peripheral cut ends of the cervical vagus. These findings suggest that the inhibition of BVB by volume loading is mediated by afferent input which is conveyed in the sympathetic nerves and ascends in the spinal cord, and produced at a central site. [Copyright &y& Elsevier]

Severe OHSS is an iatrogenic, potentially life-threatening complication of controlled ovarian hyperstimulation. Intravenous human albumin, administered around the time of oocyte retrieval has been claimed to prevent development of this serious event. It was hypothesized that albumin acts through its osmotic pressure and through the binding and inactivation, at a critical time of the cycle, of an hCG-mediated factor secreted by the corpora lutea, that impedes capillary integrity and leads to the development of OHSS. The present article evaluates the available evidence in the medical literature whether albumin is effective in reducing the risk of severe OHSS. Several trials have been identified, most of them were retrospective and few were prospective randomized controlled trials. Although albumin prophylaxis cannot offer absolute protection, all three randomized placebo-controlled trials, that have been published so far, demonstrated a significant reduction in the incidence of severe OHSS. [ABSTRACT FROM AUTHOR]

SUMMARY 1. The aims of the present study were to characterize cardiac output (CO) in transgenic mice that overexpress the β2-adrenoceptor and to evaluate ultrasonic flowmetery for continuous CO measurement in the mouse in vivo. 2. Under conditions of anaesthesia, open chest and positive ventilation, CO was determined with a transonic flowmeter at baseline and during dobutamine administration and intravenous volume loading in wild-type mice (n = 17) and β2-adrenoceptor transgenic (n = 9) and wild-type mice with chronic myocardial infarct (n = 16). 3. Compared with wild-type mice, β2-adrenoceptor transgenic mice with markedly enhanced ventricular contractility had a significantly higher CO, heart rate (HR) and maximal acceleration of aortic flow. Both dobutamine and volume loading increased CO in the two groups and higher levels of CO were measured in transgenic mice during the interventions. At baseline or during interventions, stroke volume was similar between β2-adrenoceptor transgenic and wild-type mice. Infarcted mice with impaired cardiac function had a significantly lower CO under basal and stress conditions. 4. Thus, β2-adrenoceptor transgenic mice revealed higher CO that was largely attributable to a significantly higher HR but not to an increase in stroke volume. Transonic flowmetery can detect differences in CO among mice in various functional states and is suitable for evaluation of cardiac functional reserve in mice in vivo by continuous monitoring of CO responses to different interventions. [ABSTRACT FROM AUTHOR]

Objective: To test the hypothesis that nitric oxide is beneficial in acute right heart failure after right ventricle infarct. Right ventricle infarct results in a decrease in right heart function with a subsequent reduction in ejection fraction and cardiac index. The pulmonary circulation is compromised as the right ventricle weakens, and the resulting stasis and further weakening of the ventricle present clinically as an increase in right heart afterload. Pulmonary vasodilation should ease these hemodynamic symptoms of right heart infarct.Design: Ten 3-4-month-old pigs were chosen as experimental animals. All animals were cannulated, a sternotomy was performed and branches of the right main coronary were ligated to cause infarct of the right ventricle. After a 4-h stabilization period, all animals received fluid preload with a dextrose-based solution after which control hemodynamic measurements were recorded. Treatment with inhaled nitric oxide was begun at progressive concentrations and hemodynamic measurements recorded at 30-min intervals.Results: Nitric oxide treatment significantly reduced right heart afterload, which was also apparent as a reduction in left heart preload. A significant deterioration was observed in cardiac output as well as in left and right ventricle stroke work indices.Conclusion: The use of nitric oxide in this model of right heart infarct in previously healthy young swine effected a decrease in both right heart afterload and left heart preload, with an overall deterioration in global hemodynamics. [ABSTRACT FROM AUTHOR]

Changes in myocardial loading conditions influence the ventricular action potential via mechanoelectric feedback, a mechanism impaired in pathology. In vivo the QT interval of the electrocardiogram which reflects the action potential duration allows appropriate determination of its modifications. The effects of changes in cardiac loading conditions (load reduction with trinitrin; volume loading with Plasmion) on regional function and ventricular local electrogram were investigated in conscious dogs before (control) and after 4 weeks of rapid pacing (dilated cardiomyopathy, DCM). In controls both interventions increased heart rate. Trinitrin increased end-diastolic wall thickness (EDWth, P<0.001) and reduced absolute QT interval duration (P<0.05). Plasmion decreased EDWth (P<0.001) and increased left ventricular end diastolic pressure (LVEDP, P<0.001) without QT interval alteration. However, the corrected QT interval was unchanged in both interventions. In DCM, trinitrin did not change the QT interval. Plasmion increased LVEDP (P<0.01) and prolonged QT and corrected QT intervals (P<0.01) despite the tachycardia. In controls the changes in cardiac loading conditions did not modify the QT interval, suggesting intact endogenous regulation of repolarization. The impaired adaptation observed in DCM contributed to an increase in QT interval following volume loading. In this model, a prolonged repolarization after abrupt volume loading may result from enhanced or disclosed mechanoelectric feedback. [ABSTRACT FROM AUTHOR]