Reduction In Central Venous Pressure Research Articles

Acute kidney injury in acute decompensated heart failure related cardiogenic shock: data from the Alt-Shock2 registry

Abstract Funding Acknowledgements None. Background Acute kidney injury (AKI) is one of the most common complications in patients with cardiogenic shock (CS), proving the strict relationship between heart and kidney (the so-called cardio-renal syndrome). AKI is a marker of shock severity, but also independently associated with worse outcomes. Purpose Many data are available on the prevalence of AKI in acute heart failure, but very few studies assessed the role of AKI in CS and they were mainly focused on acute myocardial infarction (AMI)-related CS. Aim of our study was to analyze the impact of AKI on acute decompensated heart failure (ADHF)-CS. Methods Between March 2020 and August 2022, we prospectively enrolled 375 CS patients from a Cardiac Intensive Care Units Network of 12 centers. Among these patients 121 (33.9% of the whole cohort) with ADHF-CS were included for the present analysis. AKI was defined according to KDIGO 2012 criteria as serum creatinine increase ≥ 0.3 mg/dl or 1.5 times compared to admission value, or urinary output < 0.5 ml/kg/h. Results Table 1 shows the baseline characteristics of the cohort. Patients with AKI were older (70 years old [55.5; 76] vs 61 [54; 69], p<0.05), had more comorbidities and a worse CS profile on admission. On multivariable analysis, SCAI stage D-E on admission was independently associated with a higher risk of AKI 24 hours after admission (OR 5.54 and p = 0.01). Treatment with mechanical circulatory support did not prevent AKI (OR 0.84 and p = 0.8). Notably, patients with a greater reduction in central venous pressure (CVP) 24 hours after admission had a lower risk of AKI (deltaCVP in AKI group 0 [-3;0] versus deltaCVP in no-AKI group -3 [-6;0], p = 0.025). Kaplan-Meier curves showed significantly worse survival in patients with AKI (Figure 1A). Cox regression analysis confirmed an association between AKI and increased risk of death (HR 2.14, CI 95% 1.16-3.96, p = 0.01). Notably, this association was even more pronounced in patients with SCAI stages A-B-C (HR 2.81, CI 95% 1.30-6.09, p = 0.01). Finally, in patients treated with renal replacement therapy (RRT) there was no association with lower survival at 180-days follow up (Figure 1B). Conclusions Our study confirms that AKI is a predictor of adverse outcomes in patients with ADHF-CS. Effective decongestion 24 hours after admission was associated with a lower risk of AKI. Considering that AKI had a negative impact even at lower SCAI stages, our findings underscore the importance of early identification of renal injury to promptly target decongestion with pharmacologic therapy and, ultimately, early use of RRT.

Positive correlation between echocardiographic tricuspid E peak velocity and central venous pressure in dogs: A preliminary study.

In the absence of vascular obstruction, central venous pressure (CVP) is a hydrostatic pressure in the cranial and caudal vena cava, providing valuable information about cardiac function and intravascular volume status. It is also a component in evaluating volume resuscitation in patients with septic shock and monitoring patients with right heart disease, pericardial disease, or volume depletion. Central venous pressure is calculated in dogs by invasive central venous catheterization, which is considered high-risk and impractical in critically ill patients. This study aimed to investigate the feasibility of using echocardiographic tricuspid E/E' as a noninvasive method to estimate CVP in anesthetized healthy dogs under controlled hypovolemic conditions. Ten male mixed-breed dogs were included in the study after a thorough health assessment. For hypovolemia induction, blood withdrawal was performed, and echocardiographic factors of the tricuspid valve, including peak E and E' velocities, were measured during CVP reduction. Repeated measures analysis of variance and Bonferroni post hoc tests were employed to compare the average difference between measured echocardiographic indices and CVP values derived from catheterization and intermittent measurement methods. Spearman's ρ correlation coefficient was used to evaluate the correlation between echocardiographic indices and CVP. E peak velocity had a significant negative correlation with venous blood pressure phases (r=-0.44, P=.001), indicating a decrease in peak E velocity with progressive CVP reduction. However, tricuspid valve E' peak velocity and E/E' did not correlate with CVP, suggesting that these parameters are not reliable for CVP estimation in dogs.

Oxygen inhalation decreases the central venous pressure in adult patients late after Fontan operations

BackgroundElevated central venous pressure (CVP) and decreased arterial oxygen saturation (SaO2) are the characteristics of patients after Fontan operations and determine morbidity and mortality in the long-term. Oxygen inhalation therapy theoretically increases SaO2 and may decrease the elevated CVP in these patients. However, there is no previous study to support this hypothesis. This study aimed to determine the acute effects of oxygen inhalation on the hemodynamics of adult patients late after Fontan operations using cardiac catheterization. MethodsThis study enrolled 58 consecutive adult patients (median age, 30 years; female, n = 24) who had undergone Fontan operations. We assessed the hemodynamic changes during oxygen inhalation (2 L/min) with a nasal cannula in cardiac catheterization. We divided the studied patients into two groups according to the reduction in CVP during oxygen inhalation using the median value: responders (>2 mmHg) and non-responders (≤2 mmHg). Clinical characteristics of the responders to oxygen inhalation were investigated with uni- and multivariate analyses. ResultsSaO2 increased from 93.3 % (91.3–94.5 %) to 97.5 % (95.2–98.4 %) (p < 0.001) and CVP decreased from 12 mmHg (11–14 mmHg) to 10 mmHg (9–12 mmHg) (p < 0.001) after oxygen inhalation. There was a weak but significant correlation between the increase in SaO2 and the decrease in CVP (R = 0.29, p = 0.025). Pulmonary blood flow increased from 4.1 L/min (3.5–5.0 L/min) to 4.4 L/min (3.7–5.3 L/min) (p = 0.007), while systemic blood flow showed no significant changes. A multivariate analysis revealed that high baseline CVP was associated with a larger decrease in CVP (>2 mmHg) after oxygen inhalation. ConclusionsOxygen inhalation increased SaO2 and decreased CVP, especially in patients with high baseline CVP. Further studies with home oxygen therapy are needed to investigate the long-term effects of oxygen inhalation in adult patients who underwent Fontan operations.

Countermeasures for Maintaining Cardiovascular Health in Space Missions.

During space exploration, the human body is subjected to altered atmospheric environments and gravity, exposure to radiation, sleep disturbance, and mental pressures; all these factors are responsible for cardiovascular diseases. Under microgravity, the physiological changes related to cardiovascular diseases are the cephalic fluid shift, dramatic reduction in central venous pressure, changes in blood rheology and endothelial function, cerebrovascular abnormalities, headaches, optic disc edema, intracranial hypertension, congestion of the jugular vein, facial swelling, and loss of taste. Generally, five countermeasures are used to maintain cardiovascular health (during and after space missions), including shielding, nutritional, medicinal, exercise, and artificial gravity. This article concludes with how to reduce space missions' impact on cardiovascular health with the help of various countermeasures.

P218 POTENTIAL ROLE OF NITROGLYCERIN FOR DIURETIC RESISTANCE IN ACUTE DECOMPENSATED HEART FAILURE: A PROOF OF CONCEPT STUDY

Abstract Background Congestion is a major determinant of end–organ dysfunction and diuretic resistance in acute decompensated heart failure (ADHF). Vasodilator therapy with nitroglycerin may help treat misdistribution of blood volume, reduce intra–abdominal pressure and improve end–organ function by recruiting capacitance veins. We assessed the role of intravenous nitroglycerin on top of maximal medical therapy to overcome diuretic resistance in ADHF patients. Methods This is a monocentric prospective study including patients with ADHF, systolic dysfunction (left ventricular ejection fraction [LVEF]&amp;lt;35%), persistent moderate–to–severe congestion and oliguria (&amp;lt;0.5 ml/Kg/h) despite high dose intravenous furosemide (&amp;gt;250 mg/die) plus a second diuretic (metolazone and/or acetazolamide). Exclusion criteria were systolic blood pressure &amp;lt; 90mmHg and eGFR &amp;lt; 20 ml/min/1.73m2. Intravenous nitroglycerin was added and uptitrated to the maximum tolerated dose while keeping the other treatments unchanged for at least 24 hours. The primary endpoint was change in urine output at 24 hours (T1) and 72 hours (T3) after nitroglycerin initiation compared to baseline (T0). Secondary endpoints were changes in central venous pressure (CVP), creatinine and total bilirubin. Results We enrolled 17 consecutive patients between March 2020 and October 2021. Mean age was 63±14 years, mean LVEF 31±15%, mean tricuspid annular plane systolic excursion 14.5±4 mm and mean eGFR 41.7±27.3 ml/min/1.73m2. 13 (76%) patients showed a cold profile; among them, 9 (69%) were on dobutamine, 5 (38%) on adrenaline and 3 (23%) on dopamine. At study enrolment all patients were receiving high dose intravenous furosemide (535±395mg/die), 8 (47%) sodium nitroprusside (0.3±0.5y/Kg/min), 9 (53%) metolazone (5mg/die) and 8 (47%) acetazolamide (250 mg/die). Urine output was significantly higher both at T1 and T3 compared to T0 (192±140ml/h vs 50±34ml/h, p &amp;lt; 0.001, and 153±87ml/h vs 50±34ml/h, p &amp;lt; 0.001, respectively; p for overall comparison&amp;lt;0.001). Also, a significant reduction of CVP was found at T1 and T3 compared to T0 (14±6mmHg vs 19±3mmHg, p = 0.025, and 12±5mmHg vs 19±3mmHg, p = 0.022, respectively; p for overall comparison=0.039). No significant changes of creatinine and total bilirubin were reported. Conclusions In this cohort of ADHF patients with diuretic resistance, adding nitroglycerin on top of maximal treatment yielded a potential benefit by significantly increasing hourly urine output whilst reducing CVP.

Transient effects of carotid baroreflex stimulation via the neck chamber device on central venous pressure.

We examined in 11 young subjects (age 29.7±3.6 years, mean±SEM) whether carotid baroreceptor stimulation via the neck chamber device may affect central venous pressure (CVP), thus potentially involving other reflexogenic areas in the examined responses. Application of progressively greater neck chamber subatmospheric pressures caused a progressive lengthening in RR interval, which reached a peak at the maximal value of negative neck chamber pressure applied. This was accompanied by significant and progressively greater reduction in CVP values when the data were calculated considering the early changes occurring within the first 2 seconds of the stimulus. There was a weak correlation between the early changes in CVP and the RR interval responses when all stimuli were pooled together (r = 0.32, P < .05). The results of the present study suggest that the neck chamber technique employed to assess carotid baroreceptor‐heart rate sensitivity can transiently affect via the CVP reduction cardiopulmonary receptors activity, which may participate at the integrated reflex responses.

Effusive–constrictive pericarditis secondary to pneumopericardium associated with gastropericardial fistula

A 66‐year‐old man with a history of gastric pull‐up reconstruction for oesophageal cancer was hospitalized because of prolonged chest pain. Chest X‐ray demonstrated pneumopericardium. Computed tomography revealed ulceration and abscess in the gastric conduit adjacent to the heart, suggesting gastropericardial fistula. As the patient did not show tamponade physiology, he was conservatively treated with antibiotics. The pneumopericardium diminished; however, he developed effusive–constrictive pericarditis with overt heart failure symptoms. Because pericardiocentesis failed to relieve the symptoms, pericardiectomy was performed. Intraoperative exploration revealed remarkably thickened pericardium and epicardium constituting multiple layers with purulent effusion. Epicardiectomy as well as pericardiectomy were required to achieve the effective reduction of central venous pressure. Perforation of the gastric conduit into the pericardial cavity was identified and repaired. Histopathology demonstrated thickened pericardium composed of hyalinized stroma, collagenous bundles, and infiltration of inflammatory cells. Streptococcus anginosus and Candida tropicalis were identified by culture of the resected tissue.

Reducing intracranial pressure by reducing central venous pressure: assessment of potential countermeasures to spaceflight-associated neuro-ocular syndrome.

Spaceflight-associated neuro-ocular syndrome (SANS) involves unilateral or bilateral optic disc edema, widening of the optic nerve sheath, and posterior globe flattening. Owing to posterior globe flattening, it is hypothesized that microgravity causes a disproportionate change in intracranial pressure (ICP) relative to intraocular pressure. Countermeasures capable of reducing ICP include thigh cuffs and breathing against inspiratory resistance. Owing to the coupling of central venous pressure (CVP) and intracranial pressure, we hypothesized that both ICP and CVP will be reduced during both countermeasures. In four male participants (32 ± 13 yr) who were previously implanted with Ommaya reservoirs for treatment of unrelated clinical conditions, ICP was measured invasively through these ports. Subjects were healthy at the time of testing. CVP was measured invasively by a peripherally inserted central catheter. Participants breathed through an impedance threshold device (ITD, -7 cmH2O) to generate negative intrathoracic pressure for 5 min, and subsequently, wore bilateral thigh cuffs inflated to 30 mmHg for 2 min. Breathing through an ITD reduced both CVP (6 ± 2 vs. 3 ± 1 mmHg; P = 0.02) and ICP (16 ± 3 vs. 12 ± 1 mmHg; P = 0.04) compared to baseline, a result that was not observed during the free breathing condition (CVP, 6 ± 2 vs. 6 ± 2 mmHg, P = 0.87; ICP, 15 ± 3 vs. 15 ± 4 mmHg, P = 0.68). Inflation of the thigh cuffs to 30 mmHg caused no meaningful reduction in CVP in all four individuals (5 ± 4 vs. 5 ± 4 mmHg; P = 0.1), coincident with minimal reduction in ICP (15 ± 3 vs. 14 ± 4 mmHg; P = 0.13). The application of inspiratory resistance breathing resulted in reductions in both ICP and CVP, likely due to intrathoracic unloading.NEW & NOTEWORTHY Spaceflight causes pathological changes in the eye that may be due to the absence of gravitational unloading of intracranial pressure (ICP) under microgravity conditions commonly referred to as spaceflight-associated neuro-ocular syndrome (SANS), whereby countermeasures aimed at lowering ICP are necessary. These data show that impedance threshold breathing acutely reduces ICP via a reduction in central venous pressure (CVP). Whereas, acute thigh cuff inflation, a popular known spaceflight-associated countermeasure, had little effect on ICP and CVP.

Temporary right ventricular circulatory support following right ventricular infarction: results of a groin-free approach.

AimsAcute right heart failure (RHF) is a severe complication of right ventricular infarction. The management of acute RHF poses a number of challenges, such as providing haemodynamic support. Temporary circulatory support (TCS) may be required upon failing medical therapy. The ProtekDuo® dual lumen cannula provides a minimally invasive option for (TCS) through a groin‐free internal jugular vein approach. We present the largest patient series to date using the ProtekDuo® cannula as temporary right ventricular assist device (t‐RVAD) in RHF after acute myocardial infarction (MI).Methods and resultsFrom July 2016 to November 2019, 10 patients underwent t‐RVAD implantation for RHF following acute MI. Transthoracic and transoesophageal echocardiography were performed in all patients to assess cardiac function, with a particular focus on RV function. Cumulative 30‐day survival was 60%. Mean TAPSE was 6.4 ± 3.1 mm, mean fractional area change was 12.1 ± 4.2%, and mean right ventricular end diastolic area was 19.8 ± 2.7 cm2. Mean implantation time was 32.8 ± 8.3 min. Mean interval after first cardiac intervention was 4.6 ± 5.8 days. Mean t‐RVAD time was 10.0 ± 7.4 days with a significant reduction in central venous pressure 19.3 ± 2.7 vs. 8.2 ± 2.6 mmHg, P < 0.001 and a significant increase in central venous saturation 52.8 ± 15.6 vs. 80.0 ± 6.0%, P < 0.001. Mean intensive care unit stay was 18.6 ± 12.2 days. Four patients were weaned from TCS. Two patients were bridged to a long‐term paracorporeal RVAD. There were no t‐RVAD associated complications. Causes of death (n = 4) were multiorgan failure, electromechanical dissociation, and haemorrhagic stroke. Mean follow‐up time was 96.0 ± 107.6 days. No independent predictors of mortality were identified in univariate analysis.ConclusionsWe show that groin‐free, percutaneous implantation of the ProtekDuo® cannula is a feasible and safe tool for TCS in acute RHF post‐MI. This approach provides the advantages of percutaneous implantation including complete mobilization and non‐surgical bedside explantation, as well as the option for adding an oxygenator to the t‐RVAD circuit.

Levosimendan Improves Oxidative Balance in Cardiogenic Shock/Low Cardiac Output Patients.

The beneficial effects exerted by levosimendan against cardiac failure could be related to the modulation of oxidative balance. We aimed to examine the effects of levosimendan in patients with cardiogenic shock or low cardiac output on cardiac systo-diastolic function and plasma oxidants/antioxidants (glutathione, GSH; thiobarbituric acid reactive substances, TBARS). In four patients undergoing coronary artery bypass grafting or angioplasty, cardiovascular parameters and plasma GSH and TBARS were measured at T0 (before levosimendan infusion), T1 (1 h after the achievement of the therapeutic dosage of levosimendan), T2 (end of levosimendan infusion), T3 (72 h after the end of levosimendan infusion), and T4 (end of cardiogenic shock). We found an improvement in the indices of systolic (ejection fraction, cardiac output, cardiac index) and diastolic (E to early diastolic mitral annular tissue velocity, E/’; early to late diastolic transmitral flow velocity, EA) cardiac function at early T2. A reduction of central venous pressure and pulmonary wedge pressure was also observed. Plasma levels of GSH and TBARS were restored by levosimendan at T1, as well. The results obtained indicate that levosimendan administration can regulate oxidant/antioxidant balance as an early effect in cardiogenic shock/low cardiac output patients. Modulation of oxidative status on a mitochondrial level could thus play a role in exerting the cardio-protection exerted by levosimendan in these patients.

Blood-saving technologies in extensive liver resections

The researches devoted to blood-saving technologies in extensive liver resections are analyzed in the manuscript. Resection of three and more liver segments is effective method of surgical treatment of various focal liver lesions. Surgical (anatomical resection with hilar glissonean access, Pringle maneuver, modern technical equipment, etc.), anesthesiological (reduction of central venous pressure, hemostatic agents) and transfusion (autologous blood donation, transfusion, cell saver, etc.) methods contribute to prevention and reduction of blood loss. Intraoperative measures for blood loss prevention should include adequate surgical incision and liver mobilization, precise techniques of parenchymal dissection (for example, cavitation surgical aspirator-destructor), use of clip applicators and local or systemic hemostatic agents.

Single Center Percutaneous Right Ventricular Assist Device Experience - 100% In-Hospital Survival Post-Left Ventricular Assist Device

Purpose Right ventricular (RV) failure is a frequent complication of left ventricular assist device (LVAD) implantation in patients with end-stage heart failure, impacting 20% of patients. Percutaneous support can be used in this scenario, however prior data supporting this approach showed survival at 30 days or hospital discharge was only 60%. Methods Retrospective review was conducted of all patients who developed severe RV failure requiring percutaneous right ventricular assist device (RVAD) following durable LVAD implant between 01/01/2017 and 07/31/2018. Patient demographics were reviewed in addition to key hemodynamic and laboratory values were collected pre-RVAD implantation and at the time of explant (post-RVAD). Pre-RVAD and post-RVAD data was compared using paired T tests. Survival at 30 days or at date of hospital discharge (whichever was longer) was considered as the primary outcome. Patient hemodynamic measures were evaluated as secondary outcomes. Results Of 41 patients who received LVAD, 10 (24%) developed severe RV failure postoperatively. Baseline characteristics include age 51±14.5 years, with 30% females. Incidence of ischemic cardiomyopathy was 20%. Most patients received LVAD as destination therapy (80%). RVAD support via percutaneous cannulation was maintained for a median duration of 15.5 days (Range - 7 to 23 days). Survival at 30 days or to hospital discharge was 100%. We observed a reduction in central venous pressure from 17.2±4.5 mm(Hg) to 11±3.1 mm(Hg), p=0.004 and an increase in LVAD flow from 4.5±0.8 l/min to 5.1±0.4 l/min, p=0.018. There was a trend towards increase in mixed venous oxygen saturation from 61.5±11.1% to 67.0±7.0%, p=0.224. Conclusion Percutaneous RVAD cannulation for treatment of RV failure after LVAD implantation provides superior early postoperative survival than traditional management techniques. These findings support broader implementation of this technique to further characterize its benefit.

Age-dependent impairment of the erythropoietin response to reduced central venous pressure in HFpEF patients.

Despite growing research interest in the pathophysiology of heart failure with preserved ejection fraction (HFpEF), it remains unknown whether central hemodynamic alterations inherently present in this condition do affect blood pressure and blood volume (BV) regulation. The present study sought to determine hemodynamic and endocrine responses to prolonged orthostatic stress in HFpEF patients. Central venous pressure (CVP) assessed via the internal jugular vein (IJV) aspect ratio with ultrasonography, arterial pressure and heart rate were determined at supine rest and during 2 hours of moderate (25–30°) head‐up tilt (HUT) in 18 stable HFpEF patients (71.2 ± 7.3 years), 14 elderly (EC), and 10 young (YC) healthy controls. Parallel endocrine measurements comprised main BV‐regulating hormones: pro‐atrial natriuretic peptide, copeptin, aldosterone, and erythropoietin (EPO). At supine rest, the IJV aspect ratio was higher (>30%) in HFpEF patients compared with EC and YC, while mean arterial pressure was elevated in HFpEF patients (98.0 ± 13.1 mm Hg) and EC (95.6 ± 8.3 mm Hg) versus YC (87.3 ± 5.0 mm Hg) (P < 0.05). HUT increased heart rate (+10%) and reduced the IJV aspect ratio (−52%), with similar hemodynamic effects in all groups (P for interaction ≥ 0.322). The analysis of endocrine responses to HUT revealed a group×time interaction for circulating EPO, which was increased in YC (+10%) but remained unaltered in HFpEF patients and EC. The EPO response to a given reduction in CVP is similarly impaired in HFpEF patients and elderly controls, suggesting an age‐dependent dissociation of EPO production from hemodynamic regulation in the HFpEF condition.

Disminución de la presión venosa central: efecto sobre el gasto cardíaco

IntroductionThe reduction of central venous pressure (CVP) below 5mmHg has been recommended to decrease bleeding during hepatic surgery. The effect of this practice on cardiac function has not been quantified. ObjectiveTo measure the repercussion of the decrease of CVP on left ventricular end diastolic volume (LVEDV) and cardiac index (CI). MethodPatients undergoing general anaesthesia for major surgery were studied. Monitoring included direct arterial pressure, CVP, and transesophageal echocardiography (TEE). During a stable period of anaesthesia, all of these parameters were measured before and after lowering CVP to 3-4mmHg. ResultsThirty-two patients were studied. Twelve patients met TEE diagnostic criteria for diastolic dysfunction (DD). Basal and post CVP reduction values of LVEDVI and CI were 49.4±13 and 40.1±13ml/m2, 2.8±0.56 and 2.5±0.7l/m2 respectively (both P<.01). All these variations were greater in patients with DD. ConclusionsReduction of CVP produced a moderate but significant decrease in LVEDV and CI This should be considered in patients with conditions that may increase the effect of decreasing the CVP.

A Case of Carcinoid Syndrome with Carcinoid Valvular Heart Disease Treated Successfully

A 39-year-old lady presented in early 2011 with Carcinoid syndrome due to Ileal Carcinoid with liver metastases and Carcinoid valvular heart disease with Right heart failure. Liver resection combined with ethanol injection of Liver metastases was carried out after reduction of Central Venous Pressure by an initial Tricuspid valve replacement (TVR), in a staged manner, with resolution of symptoms. This case highlights the necessity of TVR prior to major Liver resection for Liver metastases in Carcinoid heart disease with Tricuspid regurgitation as well as the value of treating Carcinoid heart disease aggressively.

Reduction in central venous pressure enhances erythropoietin synthesis: role of volume-regulating hormones.

Erythropoiesis is a tightly controlled biological event, but its regulation under non-hypoxic conditions, however, remains unresolved. We examined whether acute changes in central venous blood pressure (CVP) elicited by whole-body tilting affect erythropoietin (EPO) concentration according to volume-regulating hormones. Plasma EPO, angiotensin II (ANGII), aldosterone, pro-atrial natriuretic peptide (proANP) and copeptin concentrations were measured at supine rest and up to 3h during 30° head-up (HUT) and head-down tilt (HDT) in ten healthy male volunteers. Plasma albumin concentration was used to correct for changes in plasma volume and CVP was estimated through the internal jugular vein (IJV) aspect ratio with ultrasonography. From supine rest, the IJV aspect ratio was decreased and increased throughout HUT and HDT respectively. Plasma EPO concentration increased during HUT (13%; P=0.001, P for linear component=0.017), independent of changes in albumin concentration. Moreover, ANGII and copeptin concentrations increased during HUT, while proANP decreased. The increase in EPO concentration during HUT disappeared when adjusted for changes in copeptin. During HDT, EPO, ANGII and copeptin concentrations remained unaffected while proANP increased. In regression analyses, EPO was positively associated with copeptin (β=0.55; 95% CI=0.18, 0.93; P=0.004) irrespective of changes in other hormones and albumin concentration. Reduction in CVP prompts an increase in plasma EPO concentration independent of hemoconcentration and hence suggests CVP per se as an acute regulator of EPO synthesis. This effect may be explained by changes in volume-regulating hormones.

Cardiopulmonary and arterial baroreceptor unloading during passive hyperthermia does not contribute to hyperthermia-induced hyperventilation.

What is the central question of this study? Does baroreceptor unloading during passive hyperthermia contribute to increases in ventilation and decreases in end-tidal carbon dioxide during that exposure? What is the main finding and its importance? Hyperthermic hyperventilation is not mitigated by expanding central blood volume and reloading the cardiopulmonary baroreceptors via rapid saline infusion or by reloading the arterial baroreceptors via phenylephrine administration. The absence of a reduction in ventilation upon reloading the baroreceptors to pre-hyperthermic levels indicates that cardiopulmonary and arterial baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. This study tested the hypothesis that baroreceptor unloading during passive hyperthermia contributes to increases in ventilation and decreases in end-tidal partial pressure of carbon dioxide (P ET ,CO2) during that exposure. Two protocols were performed, in which healthy subjects underwent passive hyperthermia (increasing intestinal temperature by ∼1.8°C) to cause a sustained increase in ventilation and reduction in P ET ,CO2. Upon attaining hyperthermic hyperventilation, in protocol1 (n=10; three females) a bolus (19±2mlkg(-1) ) of warm (∼38°C) isotonic saline was rapidly (5-10min) infused intravenously to restore reductions in central venous pressure, whereas in protocol2 (n=11; five females) phenylephrine was infused intravenously (60-120μgmin(-1) ) to return mean arterial pressure to normothermic levels. In protocol1, hyperthermia increased ventilation (by 2.2±1.7lmin(-1) , P<0.01), while reducing P ET ,CO2 (by 4±3mmHg, P = 0.04) and central venous pressure (by 5±1mmHg, P <0.01). Saline infusion increased central venous pressure by 5±1 mmHg (P<0.01), restoring it to normothermic values, but did not change ventilation or P ET ,CO2 (P>0.05). In protocol2, hyperthermia increased ventilation (by 5.0±2.7lmin(-1) , P <0.01) and reduced P ET ,CO2 (by 5±2 mmHg, P<0.01) and mean arterial pressure (by 9±7mmHg, P <0.01). Phenylephrine infusion increased mean arterial pressure by 12±3mmHg (P<0.01), restoring it to normothermic values, but did not change ventilation or P ET ,CO2 (P>0.05). The absence of a reduction in ventilation upon reloading the cardiopulmonary and arterial baroreceptors to pre-hyperthermic levels indicates that baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans.

Reverse Trendelenburg position is a safer technique for lowering central venous pressure without decreasing blood pressure than clamping of the inferior vena cava below the liver.

Bleeding remains an important intraoperative complication in patients who undergo hepatectomy. It is generally believed that a reduction in central venous pressure will decrease bleeding from the hepatic venous system. To our knowledge, however, no study has compared the effectiveness of these techniques for controlling bleeding. So we compared the effectiveness of central venous pressure control techniques, such as infrahepatic inferior vena cava clamping, changes in surgical position of the patient, and hypoventilation anesthesia, for lowering central venous pressure. The study group comprised 50 patients who underwent hepatectomy in our department from 2012 through 2013. A central venous catheter was inserted into the right internal jugular vein, and the tip was placed in the superior vena cava. A transducer was placed along the mid-axillary line of the left side of the chest. After opening the abdomen, changes in central venous pressure were measured during inferior vena cava clamping, the reverse Trendelenburg position, the Trendelenburg position, and hypoventilation anesthesia. The inclination relative to the transducer, as measured with an inclinometer, was -10 degrees for the Trendelenburg position and +10 degrees for the reverse Trendelenburg position. The tidal volume was set at 10 mL/kg during conventional anesthesia and 5 mL/kg during hypoventilation anesthesia. The mean central venous pressure was 8.0 cm H(2)O in the supine position during conventional anesthesia, 5.0 cm H(2)O during inferior vena cava clamping, 5.6 cm H(2)O during reverse Trendelenburg position, 10.6 cm H(2)O during Trendelenburg position, and 7.6 cm H(2)O during hypoventilation anesthesia. The mean central venous pressure during inferior vena cava clamping and reverse Trendelenburg position was significantly lower than that during supine position (P = 0.0017 and P = 0.0231, respectively). The mean central venous pressure during hypoventilation anesthesia was not significantly lower than that during supine position (P = 0.9934). Mean systolic blood pressure was significantly decreased during inferior vena cava clamping (P = 0.0024), but not during reverse Trendelenburg position (P = 0.6344). Reverse Trendelenburg position decreased central venous pressure without significantly decreasing the systolic blood pressure, suggesting that it is possible to perform hepatectomy with reverse Trendelenburg position more safely than with inferior vena cava clamping.

Acute effects of haemodialysis on central venous and arterial pressure characteristics.

Haemodynamic stability of patients during haemodialysis (HD) sessions is of pivotal importance and accurate determination of dry weight remains a challenge. Little information is available about central venous and aortic pressure during dialysis. In this pilot study we used a non-invasive technique to describe the changes in central venous pressure (CVP) during dialysis. An ultrasound-assisted pressure-manometer was used at the cephalic vein during haemodialysis to quantify CVP. Central aortic pressure changes were assessed as aortic augmentation index and subendocardial viability ratio. Bioimpedance was applied to measure total body water, as well as extracellular and intracellular water before and after HD. Measurements were performed prior during and after 1 and 2 h on HD. Ten patients were included with a median age of 72 years (23-82). Haemodialysis reduced the weight by 2.0 kg, corresponding to a measured decrease in total body water of 1.9 L. The mean CVP showed a significant decrease (9.0-0.8 cmH₂O; P = 0.0005) during dialysis. The significant drop in CVP was found during the first hour (9-2.8 cmH₂O). Starting and stopping dialysis was reflected by a reduction of 2.6 cmH₂O and a rise of 2.8 cmH₂O (n.s.). Aortic augmentation index decreased from 26.1% to 21.0% (n.s.). Subendocardial viability ratio increased from 126% to 156% (P < 0.05) during HD, and decreased to 139% direct after HD (n.s.). This is the first study that illustrates a prominent reduction of CVP during the first hour of haemodialysis. Non-invasive CVP measurement is feasible during haemodialysis and adds another piece in the puzzle of factors involved in haemodynamic stability.

Infrahepatic Inferior Vena Cava Clamping for Reduction of Central Venous Pressure and Blood Loss During Hepatic Resection

Infrahepatic Inferior Vena Cava Clamping for Reduction of Central Venous Pressure and Blood Loss During Hepatic Resection