For emergency department (ED) patients in a state of circulatory shock, treatment with fluids, vasopressors and inotropes is essential for restoring blood flow to vital organs. However, recent studies have challenged the use of edarly goal directed therapy targets during resuscitation. In addition, evidence also shows that both under and over resuscitation is harmful to patients. Consequently, there exists the need for a simple non-invasive algorithm to assess if treatments are improving organ perfusion, while avoiding potential harms.
The objective of our study is to demonstrate the feasibility of using a non-invasive flow monitoring device (PhysioFlow bioimpedance device (NeuMedX Inc Bristol PA, USA)) to guide therapy (fluid bolus, vasopressor or inotrope), in conjunction with a decision algorithm. We hypothesize that flow guided treatment will improve organ perfusion and clinical outcomes for patients presenting with circulatory shock.
This is a cross-sectional, non-blinded, convenience sample, feasibility study at an academic tertiary ED. This study is intended to examine potential issues for the design of a larger trial. Inclusion criteria are: patients 18 years of age or older with any of: systolic blood pressure (SBP) < 90 mmHg, mean arterial pressure (MAP) < 65 mmHg, lactate ≥3.0 mmol/L or clinical signs of shock. Exclusion criteria are: acute myocardial infarction and/or evidence of cardiogenic shock, patients awaiting left ventricular assist device, active cardiopulmonary resuscitation, patients who have already received >1000 mL of crystalloid fluid, patients transferred from another hospital (as fluid resuscitation may have already occurred) or at the discretion of the treating physician.
Identified patients with hypo-perfusion presenting to the ED will have the PhysioFlow® device applied. The most responsible ED physician will be given the flow guided algorithm to follow. This algorithm uses blood pressure, urine output and other clinical parameters, in addition to real time non-invasive measures of flow, as triggers for treatment of hypo-perfusion with IV fluids, vasopressors, or inotropes. Physicians will be surveyed to determine if the algorithm was easy to use and if they encountered any issues.
Work Done to Date
A quality-assurance study was completed in our ICU to ensure the device was providing reliable measures. In addition, we have completed enrollment of 10 patients at one ER at the McGill University Health Centre and are now actively recruiting at a second ER. Our plan is start a multicentred RCT in early 2019.
Impact on Emergency Medicine Care
Our flow guided resuscitation study will provide valuable information for busy ED physicians. We expect that patients will benefit from reduced ICU length of stay and have fewer complications from fluid overload. Treatment non-responders can be identified earlier for transfer to ICU. We also predict that flow-guided resuscitation will result in faster stabilization of critically ill patients. With increased performance pressure on EDs in Canada, this could be a valuable initiative to reduce the burden on our strained clinical resources.