Bret Alvis, MD
Vanderbilt University Medical Center
Nashville, Tennessee
Disclosure information not submitted.
Monica Polcz, MD
Resident Physician
Vanderbilt University Medical Center
Nashville, Tennessee, United States
Disclosure information not submitted.
Eric Wise, MD, MA
Assistant Professor of Surgery
University of Minnesota Medical School
Minneapolis, Minnesota
Disclosure information not submitted.
Colleen Brophy, MD
Professor
Vanderbilt University Medical Center, United States
Disclosure information not submitted.
Kyle Hocking, PhD
Assistant Professor
Vanderbilt University, United States
Disclosure information not submitted.
Title: Vital signs, NIVA, and central parameters in a volume overload porcine model
Introduction: Hypervolemia can result in significant morbidity and mortality, especially in the critically ill. Unfortunately, there is a severe opacity of research investigating what hemodynamic parameters are best at detecting when a patient’s resuscitation results in volume overload. In this investigation, a porcine model of over-resuscitation is used to determine which hemodynamic parameters, including Non-Invasive Venous waveform Analysis (NIVA), optimally detects volume status during volume overload.
Methods: Eight pigs were anesthetized and cannulated with an arterial line and a pulmonary artery catheter. Pigs were given up to 5000 mL of Plasmalyte via a central catheter. After each 500 mL of Plasmalyte, vital signs (heart rate, systolic blood pressure, mean arterial pressure, diastolic blood pressure, NIVA Score, pulse pressure variation) and centrally obtained hemodynamic parameters (mean pulmonary artery pressure [MPAP], pulmonary capillary wedge pressure [PCWP], central venous pressure [CVP] and cardiac output [CO]) were obtained. Volume overload was analyzed using one-way ANOVA with Tukey’s post-hoc test to determine whether there were differences among each parameter over the range of volume and compared against baseline values. Conformity of parameters during the range of over-resuscitation was assessed using a Pearson correlation. The relationship of NIVA scores and PCWP was assessed using a Bland-Altman agreement analysis.
Results: Only NIVA Score and central hemodynamic parameters CVP, MPAP, CO and PCWP changed during over-resuscitation when analyzed with the Pearson correlation (p < .05). Additionally, compared to baseline, only NIVA Score, MPAP, CO, and PCWP showed significant changes in values (p < 0.05). Despite the significant linear correlation, CVP was not statistically significant from baseline to any value up to 5000 mL. When comparing NIVA and PCWP, a Bland-Altman plot was used which yielded a bias of 0.5, a standard deviation of 2.8 and 95% limits of agreement spanning -5.1 to 6.1.
Conclusions: PCWP displayed the strongest relationships to volume overload of all parameters measured. Standard vital signs did not significantly change as the pig became volume overloaded. NIVA was the only non-invasive hemodynamic parameter to significant change during volume overload.