A Porcine Model of Acute Respiratory Failure with a Continuous Infusion of Oleic Acid.

This protocol outlines an acute respiratory distress model utilizing centrally administered oleic acid infusion in Yorkshire pigs. Prior to experimentation, each pig underwent general anesthesia, endotracheal intubation, and mechanical ventilation, and was equipped with bilateral jugular vein central vascular access catheters. Oleic acid was administered through a dedicated pulmonary artery catheter at a rate of 0.2 mL/kg/h. The infusion lasted for 60-120 min, inducing respiratory distress. Throughout the experiment, various parameters including heart rate, respiratory rate, arterial blood pressure, central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, end-tidal carbon dioxide, peak airway pressures, and plateau pressures were monitored. Around the 60 min mark, decreases in partial arterial oxygen pressure (PaO2) and fraction of oxygen-saturated hemoglobin (SpO2) were observed. Periodic hemodynamic instability, accompanied by acute increases in pulmonary artery pressures, occurred during the infusion. Post-infusion, histological analysis of the lung parenchyma revealed changes indicative of parenchymal damage and acute disease processes, confirming the effectiveness of the model in simulating acute respiratory decompensation.

Adult and Pediatric Porcine Model of Acute Volume Overload.

This protocol describes an acute volume overload porcine model for adult Yorkshire pigs and piglets. Both swine ages undergo general anesthesia, endotracheal intubation, and mechanical ventilation. A central venous catheter and an arterial catheter are placed via surgical cutdown in the external jugular vein and carotid artery, respectively. A pulmonary artery catheter is placed through an introducer sheath of the central venous catheter. PlasmaLyte crystalloid solution is then administered at a rate of 100 mL/min in adult pigs and at 20 mL/kg boluses over 10 min in piglets. Hypervolemia is achieved either at 15% decrease in cardiac output or at 5 L in adult pigs and at 500 mL in piglets. Hemodynamic data, such as heart rate, respiratory rate, end-tidal carbon dioxide, fraction of oxygen-saturated hemoglobin, arterial blood pressure, central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, partial arterial oxygen pressure, lactate, pH, base excess, and pulmonary artery fraction of oxygen-saturated hemoglobin, are monitored during experimentation. Preliminary data observed with this model has demonstrated statistically significant changes and strong linear regressions between central hemodynamic parameters and acute volume overload in adult pigs. Only pulmonary capillary wedge pressure demonstrated both a linear regression and a statistical significance to acute volume overload in piglets. These models can aid scientists in the discovery of age-appropriate therapeutic and monitoring strategies to understand and prevent acute volume overload.

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.

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.

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.

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

OBJECTIVES: 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. DESIGN: A post hoc analysis of respiratory data from non-invasive venous waveform analysis among patients enrolled in an observational study was performed. SETTING: Vanderbilt University Medical Center. PATIENTS: Peripheral venous waveforms were recorded from admission to discharge in enrolled coronavirus disease 2019-positive patients and healthy age-matched controls. INTERVENTIONS: Data were analyzed in LabChart 8 to transform venous waveforms to the frequency domain using fast Fourier transforms. The peak respiratory frequency was normalized to the peak cardiac frequency to generate a respiratory non-invasive venous waveform analysis respiratory index. Paired Fisher exact tests were used to compare each patient's respiratory non-invasive venous waveform analysis respiratory index at admission and discharge. A nonparametric one-way analysis of variance was used for multiple comparisons between patients with coronavirus disease 2019 and healthy controls for respiratory non-invasive venous waveform analysis respiratory index. MEASUREMENTS AND MAIN RESULTS: Fifty coronavirus disease 2019-positive patients were enrolled between April 2020, and September 2020, and 45 were analyzed; 34 required supplemental oxygen and 11 did not. The respiratory non-invasive venous waveform analysis respiratory index was significantly higher for the 34 patients with coronavirus disease 2019 who received supplemental oxygen (median, 0.27; interquartile range, 0.11-1.28) compared with the 34 healthy controls (median, 0.06; interquartile range, 0.03-0.14) (p < 0.01). For patients with coronavirus disease 2019 who received supplemental oxygen, respiratory non-invasive venous waveform analysis respiratory index was significantly lower at hospital discharge (p = 0.02; 95% CI, 0.10-1.9) compared with hospital admission (median = 0.12; interquartile range, 0.05-0.56). For patients with coronavirus disease 2019, a respiratory non-invasive venous waveform analysis respiratory index of 0.64 demonstrated sensitivity of 92%, specificity of 47%, and positive predictive value of 93% for predicting requirement of supplemental oxygen during the hospitalization. CONCLUSIONS: Respiratory non-invasive venous waveform analysis respiratory index represents a novel physiologic respiratory measurement with a promising ability to triage early care and predict the need for oxygen support therapy in coronavirus disease 2019 patients.