# Shock With Preserved EF: Measure Forward Flow

A reassuring summary measurement should not override evidence of shock. The goal is organ perfusion with an appropriate filling-pressure balance.

![Infographic: Shock With Preserved EF: Measure Forward Flow](https://urinenephrology.org/visual-reference/images/mastery-rhc-shock.png?v=20261003c)

## EF can conceal low output

EF = stroke volume ÷ end-diastolic volume. If a small stiff ventricle holds 60 mL and ejects 33 mL, EF is 55%, yet stroke volume is low. Hypotension, cool extremities, oliguria, or rising lactate must not be dismissed because EF is preserved.

## Recognize low perfusion

Hypotension, cool extremities, altered mentation, oliguria, and rising lactate should prompt assessment of circulation even when systolic function appears preserved.

## Validate the measurements

Check zeroing, waveform quality, timing, oxygen saturations, and the method used for cardiac output. Derived values inherit measurement errors.

## Classify pressure and flow separately

High filling pressures with low output describes congestion plus impaired forward flow. It is not an instruction to give more fluid simply because BP is low. Confirm catheter measurements and integrate echo, rhythm, perfusion, and response before choosing fluid removal, vasoactive support, or another intervention.

## Treat the mechanism

Volume, vasoactive, mechanical, and disease-specific therapies have different roles. Use hemodynamics to test the physiological hypothesis and reassess response.

## Do not anchor on EF

A reassuring summary measurement should not override evidence of shock. The goal is organ perfusion with an appropriate filling-pressure balance.

## Source lessons

- [rhc cardiogenic shock](https://urinenephrology.org/mastery/cases/rhc-cardiogenic-shock.html)
- [index](https://urinenephrology.org/mastery/rhc/index.html)

Read alongside the full lessons; the findings and decisions shown here require the stated clinical context.