A nursing-led sepsis response team guiding resuscitation with point-of-care ultrasound: A review and model for improving bundle compliance while individualizing sepsis care.

A dysregulated host response to infection resulting in life-threatening organ dysfunction defines the onset of sepsis. Unfortunately, sepsis is common, costly, and deadly. The Surviving Sepsis Campaign publishes regularly updated, evidence-informed, detection, and treatment guidelines culminating in time-sensitive care "bundles.

Optimising flow without congestion using the venous-arterial Doppler enhanced resuscitation framework.

Introduction: Ultrasonography as a guide for intravenous (IV) fluid therapy is increasingly accepted within the spheres of acute care. Initial investigations and protocols often focused on measures of arterial flow as an objective approach for personalising organ 'perfusion.' More recently, and with literature associating excessive IV fluid with adverse outcomes, venous ultrasound as a measure of organ 'congestion' is taking hold.

The correlation between carotid artery Doppler and stroke volume during central blood volume loss and resuscitation.

Background: Using peripheral arteries to infer central hemodynamics is common among hemodynamic monitors. Doppler ultrasound of the common carotid artery has been used in this manner with conflicting results. We investigated the relationship between changing common carotid artery Doppler measures and stroke volume (SV), hypothesizing that more consecutively-averaged cardiac cycles would improve SV-carotid Doppler correlation.

The left ventricular outflow tract and carotid artery velocity time integrals.

The left ventricular outflow tract velocity time integral (LVOT VTI) is commonly used in the intensive care unit as a measure of stroke volume (SV) and how the SV changes in response to an intervention; therefore, the LVOT VTI is used to guide intravenous fluid management. Various peripheral Doppler surrogates are proposed to infer the LVOT VTI (e.g.

The Correlation between Carotid Artery Corrected Flow Time and Velocity Time Integral during Central Blood Volume Loss and Resuscitation.

Background: Doppler ultrasound of the common carotid artery is used to infer central hemodynamics. For example, change in the common carotid artery corrected flow time (ccFT) and velocity time integral (VTI) are proposed surrogates of changing stroke volume. However, conflicting data exist which may be due to inadequate beat sample size and measurement variability - both intrinsic to handheld systems.

Simultaneous Venous-Arterial Doppler Ultrasound During Early Fluid Resuscitation to Characterize a Novel Doppler Starling Curve: A Prospective Observational Pilot Study.

The likelihood of a patient being preload responsive-a state where the cardiac output or stroke volume (SV) increases significantly in response to preload-depends on both cardiac filling and function. This relationship is described by the canonical Frank-Starling curve. : We hypothesize that a novel method for phenotyping hypoperfused patients (ie, the "Doppler Starling curve") using synchronously measured jugular venous Doppler as a marker of central venous pressure (CVP) and corrected flow time of the carotid artery (ccFT) as a surrogate for SV will refine the pretest probability of preload responsiveness/unresponsiveness.

Inferior Vena Caval Measures Do Not Correlate with Carotid Artery Corrected Flow Time Change Measured Using a Wireless Doppler Patch in Healthy Volunteers.

(1) Background: The inspiratory collapse of the inferior vena cava (IVC), a non-invasive surrogate for right atrial pressure, is often used to predict whether a patient will augment stroke volume (SV) in response to a preload challenge. There is a correlation between changing stroke volume (SV) and corrected flow time of the common carotid artery (ccFT). (2) Objective: We studied the relationship between IVC collapsibility and ccFT in healthy volunteers during preload challenges.

A framework for heart-lung interaction and its application to prone position in the acute respiratory distress syndrome.

While both cardiac output (Q) and right atrial pressure (P) are important measures in the intensive care unit (ICU), they are outputs of the system and not determinants. That is to say, in a model of the circulation wherein venous return and cardiac function find equilibrium at an 'operating point' (OP, defined by the P on the x-axis and Q on the y-axis) the P and Q are, necessarily, variables. A simplified geometrical approximation of Guyton's model is put forth to illustrate that the variables of the system are: 1) the mean systemic filling pressure (P), 2) the pressure within the pericardium (P), 3) cardiac function and 4) the resistance to venous return.

Simultaneous venous-arterial Doppler during preload augmentation: illustrating the Doppler Starling curve.

Providing intravenous (IV) fluids to a patient with signs or symptoms of hypoperfusion is common. However, evaluating the IV fluid 'dose-response' curve of the heart is elusive. Two patients were studied in the emergency department with a wireless, wearable Doppler ultrasound system.

Carotid Artery Corrected Flow Time Measured by Wearable Doppler Ultrasound Accurately Detects Changing Stroke Volume During the Passive Leg Raise in Ambulatory Volunteers.

Background: The change in the corrected flow time of the common carotid artery (ccFTΔ) has been used as a surrogate of changing stroke volume (SVΔ) in the critically-ill. Thus, this relatively easy-to-obtain Doppler measure may help clinicians better define the intended effect of intravenous fluids. Yet the temporal evolution of SVΔ and ccFTΔ has not been reported in volunteers undergoing a passive leg raise (PLR).

A Wireless, Wearable Carotid Doppler Ultrasound Aids Diagnosis and Monitoring of Pericardial Tamponade: A Case Report.

Unlabelled: Pericardial tamponade can often be diagnosed through clinical findings and echocardiography; however, the diagnosis can be aided by demonstrating the hemodynamic consequences of the effusion. We describe the use of a wearable carotid Doppler device to help diagnose and monitor pericardial tamponade.

Case Summary: A 54-year-old man developed hypotension after an endobronchial biopsy for a lung mass.

A Novel Spectral Index for Tracking Preload Change from a Wireless, Wearable Doppler Ultrasound.

A wireless, wearable Doppler ultrasound offers a new paradigm for linking physiology to resuscitation medicine. To this end, the image analysis of simultaneously-acquired venous and arterial Doppler spectrograms attained by wearable ultrasound represents a new source of hemodynamic data. Previous investigators have reported a direct relationship between the central venous pressure (CVP) and the ratio of the internal jugular-to-common carotid artery diameters.

Detecting the Change in Total Circulatory Flow with a Wireless, Wearable Doppler Ultrasound Patch: A Pilot Study.

Unlabelled: Measuring fluid responsiveness is important in the management of critically ill patients, with a 10-15% change in cardiac output typically being used to indicate "fluid responsiveness." Ideally, these changes would be measured noninvasively and peripherally. The aim of this study was to determine how the common carotid artery (CCA) maximum velocity changes with total circulatory flow when confounding factors are mitigated and determine a value for CCA maximum velocity corresponding to a 10% change in total circulatory flow.

The effect of gravity-induced preload change on the venous excess ultrasound (VExUS) score and internal jugular vein Doppler in healthy volunteers.

Background: The venous excess ultrasound (VExUS) score is a multi-organ Doppler approach to assess venous congestion. Despite growing use of VExUS in research and clinical practice, other veins can be visualized to assess for venous hypertension, which may overcome acquisition barriers of the VExUS exam. In this pilot, observational study, we used a wearable Doppler ultrasound to assess the relationship between jugular venous Doppler and the VExUS score under different preload conditions.