Sepsis continues to claim millions of lives annually world-wide, uniting clinicians in the mission to provide optimized and personalized care. At the core of this mission is ongoing debate surrounding the optimal resuscitation strategies. Front line clinicians are caught in the fray, trying to balance the at times competing, yet overlapping, priorities of pressure and flow. This blog post delves deep into the pressure and flow discussion, exploring both parameters, and ultimately providing a practical approach to this in clinical practice.

1. The Ongoing Debate
Every day in the corridors of EDs, hospital wards, and ICUs are discussions about the ideal metrics for the resuscitation of sepsis. Some clinicians choose the widely available metric of mean arterial pressure (MAP), whereas others argue that ‘flow’ (cardiac output) to organs takes priority. Both metrics, when scrutinized, offer insights into the macrocirculatory dysfunction observed in sepsis, but how do we integrate these concepts?

Traditionally, medicine has leaned heavily on pressure metrics like MAP, however, multiple studies assessing different MAP targets for critically ill patients and sepsis have failed to show a benefit of one MAP over another. Some critics of these studies cite the lack of personalization of a ‘One MAP fits all’ approach, where others feel these studies demonstrate that MAP may be less important than we once thought. Regardless of the reason, contemporary thinking and research has shifted towards optimizing ‘flow’.

2. Shifting the Focus to Flow
Proponents of a ‘flow’ paradigm argue that during the complex interplay of sepsis pathophysiology, ‘flow’ is more important for organ perfusion than pressure. Consider cardiogenic shock, a scenario where the cardiac output can be severely decreased (with organ dysfunction), but the patient can have entirely normal blood pressure. This is because the body increases peripheral resistance to offset low flow, often at the expense of organ perfusion.

When we think of sepsis, we typically think of distributive shock with vasodilation and low peripheral vascular resistance. The reality is far more complicated. Septic shock has multiple presentations in addition to vasodilation: hypovolemia due to decreased intake or fluid leakage, low cardiac output from septic cardiomyopathy, or even obstructive shock due to high pulmonary pressures. This complexity has forced innovators to develop novel solutions to quantify flow.

3. Quantifying Flow
Our existing diagnostic arsenal to quantify flow are limited, and require expensive, invasive, and inaccessible equipment. While pulmonary artery catheters, NICOM monitors, and comprehensive echocardiography provide insights, they are often not available to frontline clinicians. This had led to calls within the emergency medicine, hospitalist, and critical care communities to develop non-invasive, rapid, and cost-effective solutions to tailor resuscitation. This includes assessing patients for markers of fluid responsiveness (will IV fluids actually increase their flow?) and fluid tolerance (will IV fluids cause harm?).

4. A unified approach to pressure and flow
We advocate for a unified approach to pressure and flow. The first step is to ensure an adequate MAP (which may vary per patient) to defend the critical organ perfusion pressure, but then, we should turn our attention to quantifying and optimizing flow. While there are many methods to quantify flow, the one you choose should be accessible, cost effective, and able to quantify fluid responsiveness (benefit of fluids), and fluid tolerance (harms of fluids).
The FloPatch is one solution that allows clinicians to individualize flow at the bedside. With FloPatch, you can monitor the response to vasopressors, inotropes, and IV fluids in real-time to personalize fluid management. This ensures you aren’t increase pressure, at the expense of flow.

5. Lets come together (right now)
Perhaps it’s time to transcend the false pressure vs. flow dichotomy. Instead of choosing on one over the other, why not utilize both? With FloPatch, you can seamlessly integrate both metrics, optimizing care for septic patients. The future of sepsis care promises to be an exciting one, and with the right tools, we can provide physiology informed, evidence based, and personalized care to our patients that need it most.