Hemodynamic Parameters in the Assessment of Fluid Status in a Porcine Hemorrhage and Resuscitation Model

Development of a Direct Non-Puncture Device for Measuring Portal Venous Pressure during Liver Transplantation-A Swine Model

Portal hypertension-related complications pose a significant risk for liver failure post-transplantation. Thus, accurate monitoring of intraoperative portal venous pressure (PVP) is crucial. However, current PVP monitoring techniques requiring direct percutaneous puncture carry the risk of graft damage. In this study, we present an innovative non-puncture PVP monitoring device (PVPMD) using a 3D-printed prototype. PVPMD design is inspired by the sphygmomanometer principle, and strategically encompasses the portal vein and enables precise PVP measurement through blood flow ultrasonography after temporary occlusion. By a series of mini-pig experiments, the prototype PVPMD demonstrated a strong correlation with invasive catheter measurements in the main trunk of the portal vein (rs = 0.923, p = 0.000). There was a significant repeatability and reproducibility between the prototype PVPMD- and invasive catheter-measured PVP. This indicates that the PVPMD holds immense potential for direct application in liver transplantation and surgery. Moreover, it has the potential to replace catheter-based central venous pressure (CVP) measurements, thereby mitigating catheter-related complications during many surgeries. In conclusion, our innovative device represents a significant advancement in PVP monitoring during liver transplantation, with comprehensive validation from principle exploration to successful animal experiments. We anticipate that this groundbreaking PVPMD will attract the attention of researchers and clinicians, propelling the noninvasive measurement of PVP or other venous/arterial pressures into a new era of clinical practice.

Evaluation of common clinical and hemodynamic parameters to pulmonary capillary wedge pressures in patients undergoing right heart catheterization

Introduction

A cornerstone of heart failure assessment is the right heart catheterization and the pulmonary capillary wedge pressure measurement it can provide. Clinical and hemodynamic parameters such as weight and jugular venous distention are less invasive measures often used to diagnose, manage, and treat these patients. To date, there is little data looking at the association of these key parameters to measured pulmonary capillary wedge pressure (PCWP). This is a large, retrospective, secondary analysis of a right heart catheterization database comparing clinical and hemodynamic parameters against measured PCWP in heart failure patients.

Methods

A total of 538 subjects were included in this secondary analysis. Spearman's Rho analysis of each clinical and hemodynamic variable was used to compare their association to the documented PCWP. Variables analyzed included weight, body mass index (BMI), jugular venous distention (JVD), creatinine, edema grade, right atrial pressure (RAP), pulmonary artery systolic pressure (PASP), systemic vascular resistance, pulmonary vascular resistance, cardiac output (thermal and Fick), systolic blood pressure, diastolic blood pressure, heart rate, respiratory rate, oxygen saturation (SpO2), and pulmonary artery diastolic pressure (PADP).

Results

Ten out of 17 selected parameters had a statistically significant association with measured PCWP values. PADP had the strongest association (0.73, p<0.0001), followed by RAP and PASP (0.69, p<0.0001 and 0.67, p<0.0001, respectively). Other significant parameters included weight (0.2, p<0.001), BMI (0.2, p<0.001), SpO2 (-0.17, p<0.0091), JVD (0.24, p<0.005) and edema grade (0.2, p<0.0001).

Conclusion

This retrospective analysis clarifies the associations of commonly used clinical and hemodynamic parameters to the clinically used gold standard for volume assessment in heart failure patients, PCWP.

The Effect of Fluid Pre-loading on Vital Signs and Hemodynamic Parameters in a Porcine Model of Lipopolysaccharide-Induced Endotoxemia

Background Animal models of distributive hypotension and resuscitation allow the assessment of hemodynamic monitoring modalities and resuscitation strategies. The fluid-first paradigm for resuscitation is currently being challenged with clinical trials. In this investigation, venous return and perfusion are assessed, and full hemodynamics are characterized, in a porcine model of endotoxemic hypotension with and without fluid pre-loading. Methods Two groups of six pigs had the induction of standardized endotoxemic hypotension ("critical hypotension"). Group 1 underwent four 10 cc/kg crystalloid boluses, and Group 2 was not fluid pre-resuscitated. Both groups underwent progressive norepinephrine (NE) up-titration to 0.25 mcg/kg/minute over 30 minutes. Vital signs, central parameters, and laboratory values were obtained at baseline, "critical hypotension," after each bolus and during NE administration. Results Endotoxemia decreased the systemic vascular resistance (SVR) in Group 1 (1031±106 dyn/s/cm-5 versus 738±258 dyn/s/cm-5; P=0.03) and Group 2 (1121±196 dyn/s/cm-5 versus 759±342 dyn/s/cm-5; P=0.003). In Group 1, the four fluid boluses decreased heart rate (HR), pulmonary capillary wedge pressure (PCWP), and central venous pressure (CVP) (P<0.05). No changes were observed in blood pressure, cardiac output (CO), or lactate. NE up-titration increased HR in Group 1 and decreased CVP in both groups. Higher final CVP (11 {3} versus 4 {4} mmHg; P=0.01) and PCWP (5 {1} versus 2 {2} mmHg; P=0.005) values were observed in Group 1 relative to Group 2, reflecting increased venous return. Conclusions Porcine endotoxemic hypotension and resuscitation were robustly characterized. In this model, fluid loading improved venous return with NE, though perfusion (CO) was preserved by increased NE-induced chronotropy.

Central Venous Waveform Analysis and Cardiac Output in a Porcine Model of Endotoxemic Hypotension and Resuscitation

BACKGROUND

Cardiac output (CO) is a valuable proxy for perfusion, and governs volume responsiveness during resuscitation from distributive shock. The underappreciated venous system has nuanced physiology that confers valuable hemodynamic information. In this investigation, deconvolution of the central venous waveform by the fast Fourier transformation (FFT) algorithm is performed to assess its ability to constitute a CO surrogate in a porcine model of endotoxemia-induced distributive hypotension and resuscitation.

STUDY DESIGN

Ten pigs were anesthetized, catheterized, and intubated. A lipopolysaccharides infusion protocol was used to precipitate low systemic vascular resistance hypotension. Four crystalloid boluses (10 cc/kg) were then given in succession, after which heart rate, mean arterial pressure, thermodilution-derived CO, central venous pressure (CVP), and the central venous waveform were collected, the last undergoing fast Fourier transformation analysis. The amplitude of the fundamental frequency of the central venous waveform's cardiac wave (f0-CVP) was obtained. Heart rate, mean arterial pressure, CVP, f0-CVP, and CO were plotted over the course of the boluses to determine whether f0-CVP tracked with CO better than the vital signs, or than CVP itself.

RESULTS

Distributive hypotension to a 25% mean arterial pressure decrement was achieved, with decreased systemic vascular resistance (mean 918 ± 227 [SD] dyne/s/cm-5 vs 685 ± 180 dyne/s/cm-5; p = 0.038). Full hemodynamic parameters characterizing this model were reported. Slopes of linear regression lines of heart rate, mean arterial pressure, CVP, f0-CVP, and CO were -2.8, 1.7, 1.8, 0.40, and 0.35, respectively, demonstrating that f0-CVP values closely track with CO over the 4-bolus range.

CONCLUSIONS

Fast Fourier transformation analysis of the central venous waveform may allow real-time assessment of CO during resuscitation from distributive hypotension, possibly offering a venous-based approach to clinical estimation of volume responsiveness.

Noninvasive Venous Waveform Analysis Correlates With Pulmonary Capillary Wedge Pressure and Predicts 30-Day Admission in Patients With Heart Failure Undergoing Right Heart Catheterization

BACKGROUND

Heart failure is the leading cause of hospitalization in the elderly and readmission is common. Clinical indicators of congestion may not precede acute congestion with enough time to prevent hospital admission for heart failure. Thus, there is a large and unmet need for accurate, noninvasive assessment of congestion. Noninvasive venous waveform analysis in heart failure (NIVAHF) is a novel, noninvasive technology that monitors intravascular volume status and hemodynamic congestion. The objective of this study was to determine the correlation of NIVAHF with pulmonary capillary wedge pressure (PCWP) and the ability of NIVAHF to predict 30-day admission after right heart catheterization.

METHODS AND RESULTS

The prototype NIVAHF device was compared with the PCWP in 106 patients undergoing right heart catheterization. The NIVAHF algorithm was developed and trained to estimate the PCWP. NIVA scores and central hemodynamic parameters (PCWP, pulmonary artery diastolic pressure, and cardiac output) were evaluated in 84 patients undergoing outpatient right heart catheterization. Receiver operating characteristic curves were used to determine whether a NIVA score predicted 30-day hospital admission. The NIVA score demonstrated a positive correlation with PCWP (r = 0.92, n = 106, P < .0001). The NIVA score at the time of hospital discharge predicted 30-day admission with an AUC of 0.84, a NIVA score of more than 18 predicted admission with a sensitivity of 91% and specificity of 56%. Residual analysis suggested that no single patient demographic confounded the predictive accuracy of the NIVA score.

CONCLUSIONS

The NIVAHF score is a noninvasive monitoring technology that is designed to provide an estimate of PCWP. A NIVA score of more than 18 indicated an increased risk for 30-day hospital admission. This noninvasive measurement has the potential for guiding decongestive therapy and the prevention of hospital admission in patients with heart failure.

Congenital portopulmonary shunt in a cat

A 9-year-old spayed female crossbreed cat with chief complaints of anorexia and hypersalivation had high serum concentrations of ammonia and fasting and postprandial total bile acid. Therefore, she was referred to our hospital. On the first evaluation, haematology, serum chemistry, radiography and ultrasonography findings suggested that she had a congenital portosystemic shunt. CT revealed a shunt vessel from the left gastric vein to the left pulmonary vein. During median celiotomy and sternotomy, gross findings and mesenteric portography revealed abnormal vessel shunting from the left gastric vein to the left pulmonary vein. Complete ligation of the shunt vessel was achieved. She recovered without any complications. Postoperative serum chemistry revealed that ammonia and total bile acid levels decreased to within the reference intervals. This report is the first to describe the clinical features and surgical outcome of a cat with a congenital portopulmonary shunt.

Comparison of clinical symptoms and bioimpedance to pulmonary capillary wedge pressure in heart failure

Introduction

Clinical symptoms of heart failure commonly include fatigue, edema, and shortness of breath. Unfortunately, clinical monitoring has proven unreliable in predicting congestion and the need for hospitalization. Biosensing wearables have been developed as a potential adjunct to clinical signs and symptoms to detect congestion before it becomes severe thus preventing a heart failure hospitalization.

Hypothesis

Clinical signs and symptoms of heart failure will correlate with thoracic bioimpedance measurements (ZOE®) and pulmonary capillary wedge pressure (PCWP).

Methods

One hundred and fifty-five subjects undergoing right heart catheterization (RHC) were prospectively enrolled. A Zo value (ohms) was obtained, jugular venous pressure (JVP) was estimated, edema graded, and shortness of breath (SOB) assessed in all subjects. RHC was performed by a scheduled cardiologist per routine. One-way ANOVA was performed to assess the relationship between variables. A Pearson correlation coefficient was used to compare the Zo value and PCWP.

Results

Neither estimated JVP (cmH2O) (p = 0.65, n = 110) nor edema scores (p = 0.12, n = 110) demonstrated a significant relationship to PCWP. The presence of subjective SOB also did not demonstrate a significant association with PCWP (p = 0.99, n = 110). There was no correlation between ZOE® and PCWP (r = -0.08, p = 0.56, n = 56).

Conclusions

These findings support the idea that traditional measures for monitoring heart failure patients are limited.

Respiratory Non-Invasive Venous Waveform Analysis for Assessment of Respiratory Distress in Coronavirus Disease 2019 Patients: An Observational Study

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Due to the rapid rate of severe acute respiratory syndrome coronavirus 2 transmission and the heterogeneity of symptoms of coronavirus disease 2019, expeditious and effective triage is critical for early treatment and effective allocation of hospital resources.