OBJECTIVETo assess the significance of stroke volume variation (SVV) and intrathoracic blood volume index (ITBI) on the responsiveness to volume loading in mechanically ventilated canine with hemorrhagic shock.

METHODSHemorrhagic shock canine model was established with the modified Wiggers' method. The heart rate (HR), mean artery pressure (MAP), central venous pressure (CVP), pulmonary artery wedge pressure (PAWP), intrathoracic blood volume index (ITBI) and stroke volume variation (SVV) were investigated by Swan-Ganz catheter or PiCCO monitor. Graded volume loading (VL) was performed. Successive responsive VLs were performed (increase in SV > 5% after VL) until continuous change in SV < 5% (unresponsive) was reached.

RESULTSFourteen canines were studied and a total of 134 VLs were performed. In 94 VLs, an increase in SV of more than 5% was reached. In the other 40 VLs, increase in SV was less than 5%. The change of HR, MAP, ITBI, SVV in responsive were more than those of unresponsive after VL. The change of CVP, PAWP in responsive were less than those of unresponsive. Significant correlation was found between DeltaSV after VL and the baseline values of ITBI, SVV. No correlation was found between DeltaSV and HR, MAP, CVP, PAWP. Significant correlations were also found between DeltaSV and DeltaCVP, DeltaPAWP, DeltaITBI, DeltaSVV after fluid loading. No correlation was found between DeltaSV and DeltaHR, DeltaMAP. By using receiver operating characteristic analysis, the area under the curve were 0.872 for SVV and 0.689 for ITBI, more than those of HR, MAP, CVP, PAWP statistically. As SVV value of 9.5% or more will predict an increase in the SV of at least 5% in response to a VL with a sensitivity of 92.6% and a specificity of 82.5%.

CONCLUSIONSSVV and ITBI were more useful indicators than CVP and PAWP on the assessment of responsiveness to volume loading. SVV as a functional preload parameter and for on-line monitoring may help to improve the hemodynamic management.

Animals ; Blood Volume ; physiology ; Blood Volume Determination ; methods ; Dogs ; Female ; Male ; Shock, Hemorrhagic ; diagnosis ; physiopathology ; Stroke Volume ; physiology

In this paper, we propose the construction of a fifth-order Windkessel model, and give complete mathematical solutions for this model. Utilizing the diastolic pulse wave analytical methods, we derived the parameters of the mathematical model. The parameters were further applied to estimate arterial compliance, blood flow inertia, peripheral resistance and other indices. With simulation tools we assess the validity of the model, and built a simulation circuit with the model parameters R, C and L. The model parameters were obtained from the high-order Windkessel model. The stroke volume of left ventricle is employed as the input of the simulation circuit. At the end of the circuit, the responding signal was gained. And it in turn was compared with the measured pulse waveform. The results show that the fifth-order Windkessel model is superior to the third-order Windkessel model in the pulse wave fitting and stability, and thus better reflects the role of microvessles in the circulatory system.
Algorithms ; Blood Vessels ; physiology ; Compliance ; Computer Simulation ; Humans ; Microcirculation ; physiology ; Models, Cardiovascular ; Stroke Volume ; physiology

The production of miniature animals has been suggested for use in organ transplantation. At present, many of the studies about application of animal organs to human have been focused on pigs because of the number of advantages involved and due to their similarities with human. However, a physiological analysis of the organs to be transplanted has not yet been carried out. Therefore, this study analyzed whether or not there were physiological and morphological differences in the hearts of conventionallyreared pigs and micropigs. In this study, the morphological and physiological functions of the heart were examined using radiographic and echocardiographic equipment. In the lateral radiographic view, the heart of the micropig has a larger cardiac long axis : short axis ratio than does the conventional pig, but the difference in the vertebral heart score was not significant. In addition, there were no morphological differences on the X-ray fluoroscopic view. There were no differences in echocardiographic values, except for several values in the left ventricle traces. Overall, it is expected that the values measured in this study will contribute to understanding of the physiological characteristics of micropigs.
Animals ; Echocardiography/veterinary ; Fluoroscopy/veterinary ; Heart/*physiology/*radiography ; Stroke Volume/physiology ; Swine ; Swine, Miniature

BACKGROUNDStroke volume variation (SVV) is a robust indicator of fluid responsiveness during volume change. We compared the sensibility of SVV by Vigileo/Flotrac to central venous pressure (CVP) when volume changes in patients undergoing intraoperative acute normovolemic hemodilution (ANH) and acute hypervolemic hemodilution (AHH).

METHODSForty patients were randomly divided into an ANH group (n = 20) and an AHH group (n = 20). All patients received general anesthesia and were mechanically ventilated. Data were collected from 7 different time-points in the ANH group: baseline, after withdrawal of 5%, 10%, and 15% of the estimated blood volume (EBV) and after replacement with an equal volume of 6% hydroxyethyl starch 130/0.4 (HES) in 5% EBV increments to baseline. There were four time points in the AHH group: baseline, after 5%, 10%, and 15% expansion of the EBV with 6% HES. At each time-point, CVP, SVV and other hemodynamic parameters measurements were obtained.

RESULTSAfter removal of 10% and 15% EBV, SVV significantly increased from 10.9 ± 3.0 to 14.1 ± 3.4 and 10.9 ± 3.0 to 16.0 ± 3.3 (P < 0.01), and returned to a final value of 10.6 ± 3.4 after volume replacement. The CVP value was unchanged after removal and replacement of 15% of the EBV. There were no significant changes in SVV after 5%, 10% whereas there was a significant reduction after 15% (8.2 ± 1.7) expansion of the EBV compared with baseline (9.9 ± 1.8) (P = 0.033). However, there was a significant increase in CVP after 10% (10.3 ± 2.4), 15% (11.3 ± 2.2) expansion of the EBV compared with baseline (8.2 ± 2.7) (P < 0.01).

CONCLUSIONSVV is a more sensitive parameter for volume than CVP during hypovolemia, on the contrary CVP is more sensitive than SVV during hypervolemia.

Anesthesia ; Central Venous Pressure ; physiology ; Hemodilution ; Humans ; Hypovolemia ; physiopathology ; Stroke Volume ; physiology

Echocardiography, Transesophageal ; Humans ; Monitoring, Physiologic ; standards ; Pulmonary Circulation ; physiology ; Pulmonary Wedge Pressure ; Stroke Volume

BACKGROUNDThe term heart failure with normal ejection fraction (HFNEF) is often used to describe the syndrome of heart failure with normal ejection fraction. Based on the previous studies, HFNEF has a significant morbidity and mortality and is associated with a similar prognosis to heart failure with reduced ejection fraction (HFREF). The present study aimed to investigate the clinical characteristics and prognosis of HFNEF in elderly patients.

METHODSConsecutive elderly patients (≥ 60 years old) hospitalized for the first episode of heart failure (HF) in Beijing Hospital from January 2003 to December 2009 were retrospectively recruited. Three hundred and ten patients with HF were eligible for our study. As recently recommended, a cut-off value of 50% was used to distinguish HFNEF (LVEF ≥ 50%) from HFREF (LVEF < 50%). Data were retrospectively obtained from hospital records and databases. Follow-up data were obtained by telephone and from hospital records. For every eligible patient, the clinical characteristics and prognosis were collected and compared between the HFNEF and HFREF groups.

RESULTSPatients with HFNEF accounted for 54.5% of all cases of elderly patients with HF. Compared with HFREF, the elderly patients with HFNEF had a higher proportion of females (62.1% vs. 32.6%, P < 0.001), higher body mass index (BMI) ((24.9 ± 4.7) vs. (23.5 ± 4.0) kg/m(2), P = 0.011), higher systolic blood pressure at admission ((141.5 ± 22.6) vs. (134.3 ± 18.6) mmHg, P = 0.002), but lower hemoglobin levels ((118.3 ± 22.7) vs. (125.8 ± 23.8) g/L, P = 0.005). The incidence of coronary heart disease (43.2% vs. 65.2%, P < 0.001) and myocardial infarction (16.6% vs. 46.1%, P < 0.001) were significantly lower in elderly patients with HFNEF than in those with HFREF (P < 0.001). With a mean follow-up of 33.5 (0.5 - 93) months, 120 patients (38.7%) died, including 94 (30.3%) cardiac deaths. The HFNEF group had fewer deaths than the HFREF group at the end of the first follow-up (46/169 (27.2%) vs. 58/141 (41.1%)) and at the end of the second follow-up (56/169 (33.1%) vs. 64/141 (45.4%)). Kaplan-Meier survival analysis showed a significantly higher survival rate in elderly patients with HFNEF than those with HFREF (P = 0.021 for total mortality and P < 0.001 for cardiac mortality). Multiple Logistic regression analysis showed that LVEF < 50% was an independent risk factor for death in elderly patients with HF.

CONCLUSIONSMore than half of elderly patients with HF have a normal LVEF. The prognosis of the elderly patients with HFNEF is poor, though slightly better than the elderly patients with HFREF.

Aged ; Aged, 80 and over ; Female ; Heart Failure ; pathology ; Humans ; Male ; Middle Aged ; Prognosis ; Stroke Volume ; physiology

Heart failure with preserved ejection fraction (HFpEF) is a syndrome with highly heterogeneous clinical symptoms, and its incidence has been increasing in recent years. Compared with heart failure with reduced ejection fraction (HFrEF), HFpEF has a worse prognosis. Traditional therapies targeting the internal mechanisms of the heart show limited or inefficacy on HFpEF, and new therapeutic targets for HFpEF are expected to be found by focusing on the extracardiac mechanisms. Recent studies have shown that cardiopulmonary pathophysiological interaction exacerbates the progression of HFpEF. Hypertension, systemic vascular injury, and inflammatory response lead to coronary microvascular dysfunction, myocardial hypertrophy, and coronary microvascular remodeling. Acute kidney injury affects myocardial energy production, induces oxidative stress and catabolism of myocardial protein, which leads to myocardial dysfunction. Liver fibrosis mediates heart injury by abnormal protein deposition and inflammatory factors production. Skeletal muscle interacts with the sympathetic nervous system by metabolic signals. It also produces muscle factors, jointly affecting cardiac function. Metabolic syndrome, gut microbiota dysbiosis, immune system diseases, and iron deficiency promote the occurrence and development of HFpEF through metabolic changes, oxidative stress, and inflammatory responses. Therefore, the research on the extracardiac mechanisms of HFpEF has certain implications for model construction, mechanism research, and treatment strategy formulation.
Humans ; Heart Failure/diagnosis* ; Stroke Volume/physiology* ; Myocardium/metabolism* ; Cardiomyopathies/metabolism* ; Hypertension ; Ventricular Function, Left

Objective: To analyze the characteristics, diagnosis and treatment status of Takotsubo syndrome (TTS) of Chinese patients. Methods: Complete literature review was performed to summarize Chinese TTS cases between 2007 and 2018. Results: A total of 131 literatures were included including 160 TTS patients (age (58.3±14.7) years). There were 137 female patients (85.6%) in this cohort, the age was (59.6±14.0) years. There were 124 cases (77.5%) of stress-evoking factors, of which 83 cases (66.9%) were self-stress factors. There were 97 cases (60.6%) complained of chest pain and 15 cases (9.4%) with syncope. Forty-eight cases (30.0%) presented with cardiogenic shock. CK-MB and cTnT/I increased in 109 cases (80.1%). There were 124 cases (77.5%) presented with ST segment elevation on electrocardiogram, which were common in lead V₂-V₅. Echocardiography results were available in 128 cases (80.0%), reduced left ventricular ejection fraction (<50%) was reported in 78 cases (73.6%). Coronary angiography was performed in 133 patients (83.1%), of which 126 patients (94.7%) had normal coronary arteries or single non-significant stenosis. One hundred and thirty-eight patients (87.3%) were apical type. The misdiagnosis rate on admission was 96.9% (155/160), of which 141 cases (88.1%) were misdiagnosed as acute myocardial infarction. Nitroglycerin was used in 36 patients (30.3%). Angiotensin converting enzyme inhibitor or angiotensin Ⅱ receptor antagonist were used in 38 patients (31.9%). β blockers were used in 46 patients (38.7 %). Dopamine was used in 22 cases (18.5%) and norepinephrine was used in 12 cases (10.1%). Intra-aortic balloon counter pulsation was used in 5 cases (3.1%). Cardiopulmonary resuscitation was performed in 9 cases (5.6%). Cardiac function recovery time was 7 (6, 15) days. The average InterTAK diagnosis score was (51.5±18.1) points, and value was>70 points in 2 cases (1.3%). There were 92 patients in the high-risk group, and there were 3 recurrent TTS cases. Five patients died. Conclusions: TTS incidence tends to be young and dominates in female in China. The misdiagnosis rate is extremely high on admission. Most patients are treated with medication.
Adult ; Aged ; Echocardiography ; Electrocardiography ; Female ; Humans ; Middle Aged ; Stroke Volume/physiology* ; Takotsubo Cardiomyopathy/diagnosis* ; Ventricular Function, Left/physiology*

Age Factors ; Cardiac Output ; physiology ; Cardiography, Impedance ; methods ; Child ; Child, Preschool ; Electric Impedance ; Female ; Heart ; physiology ; Humans ; Male ; Stroke Volume ; physiology ; Tomography ; methods

BACKGROUNDFew studies have reported the effect of different volume responsiveness evaluation methods on volume therapy results and prognosis. This study was carried out to investigate the effect of two volume responsiveness evaluation methods, stroke volume variation (SVV) and stroke volume changes before and after passive leg raising (PLR-ΔSV), on fluid resuscitation and prognosis in septic shock patients.

METHODSSeptic shock patients admitted to the Department of Critical Care Medicine of Zhejiang Hospital, China, from March 2011 to March 2013, who were under controlled ventilation and without arrhythmia, were studied. Patients were randomly assigned to the SVV group or the PLR-ΔSV group. The SVV group used the Pulse Indication Continuous Cardiac Output monitoring of SVV, and responsiveness was defined as SVV ≥12%. The PLR-ΔSV group used ΔSV before and after PLR as the indicator, and responsiveness was defined as ΔSV ≥15%. Six hours after fluid resuscitation, changes in tissue perfusion indicators (lactate, lactate clearance rate, central venous oxygen saturation (SCVO2), base excess (BE)), organ function indicators (white blood cell count, neutrophil percentage, platelet count, total protein, albumin, alanine aminotransferase, total and direct bilirubin, blood urea nitrogen, serum creatinine, serum creatine kinase, oxygenation index), fluid balance (6- and 24-hour fluid input) and the use of cardiotonic drugs (dobutamine), prognostic indicators (the time and rate of achieving early goal-directed therapy (EGDT) standards, duration of mechanical ventilation and intensive care unit stay, and 28- day mortality) were observed.

RESULTSSix hours after fluid resuscitation, there were no significant differences in temperature, heart rate, blood pressure, SpO2, organ function indicators, or tissue perfusion indicators between the two groups (P > 0.05). The 6- and 24-hour fluid input was slightly less in the SVV group than in the PLR-ΔSV group, but the difference was not statistically significant (P > 0.05). The SVV group used significantly more dobutamine than the PLR-ΔSV group (33.3% vs. 10.7%, P = 0.039). There were no significant differences in the time ((4.8±1.4) h vs. (4.3±1.3) h, P = 0.142) and rate of achieving EGDT standards (90.0% vs. 92.9%, P = 0.698), or in the length of mechanical ventilation and ICU stay. The 28-day mortality in the SVV group (16.7% (5/30)) was slightly higher than the PLR-?SV group (14.3% (4/28)), but the difference was not statistically significant (P = 0.788).

CONCLUSIONSIn septic shock patients under controlled ventilation and without arrhythmia, using SVV or PLR-ΔSV methods to evaluate volume responsiveness has a similar effect on volume therapy results and prognosis. The evaluation and dynamic monitoring of volume responsiveness is more important for fluid resuscitation than the evaluation methods themselves. Choosing different methods to evaluate volume responsiveness has no significant influence on the effect of volume therapy and prognosis.

Adult ; Female ; Fluid Therapy ; Humans ; Male ; Middle Aged ; Monitoring, Physiologic ; methods ; Shock, Septic ; pathology ; therapy ; Stroke Volume ; physiology