How to Use This Book

Chapter anatomy

Every clinical chapter is built to the same sequence, so that the same information is always in the same place:

Reading paths

The systematic path. Part I → Part II → Part III → Part IV → Part V. This is the training path and assumes you want the physics before the physiology before the pathology.

The syndrome path. Start in Part V at the clinical problem in front of you; each syndrome chapter links back to the parameter chapters it depends on. This is the reference path.

The parameter path. Appendix B lists every measurement with its normal range, its severity grading, and the chapter that explains it.

Conventions

• Bold thresholds are the primary decision cut-offs.
• Equations are reproduced in Appendix A with their worked example.
• An Evidence quality callout marks a statement resting on expert opinion or on extrapolation from non-ICU populations.
• Every velocity is stated with its unit; tissue Doppler and mitral inflow in cm/s, CW jets in m/s.

A note on thresholds

A threshold is a decision boundary chosen to trade sensitivity against specificity in a defined population. Applied outside that population it is not merely less accurate — it may be meaningless. Wherever a threshold's validation population differs materially from the ICU population, this book says so.

Treating a guideline cut-off as a physical constant is the single commonest error in critical care echocardiography.

Where guidelines disagree

This book does not average conflicting numbers into an invented consensus. Both positions are given with their attribution. The recurring examples: