Q: Which of the following have been proposed (may not have strong evidence) to measure  fluid responsiveness? 

A) Oximetric waveform variation (plethysmographic waveform of the pulse oximeter) 
B) Vena cava assessment
C) Assessment of B-lines on lung ultrasound 
D) Femoral vein diameter 
E) All of the above


Answer:  E

Objective of above question is to introduce various measures which have been used - though may not be clinically evidence based to assess fluid responsiveness in hemodynamically unstable patients. 

If you notice, passive leg raising, point-of-care echocardiography or arterial line based waveform analysed hemodynamic data are not included in the question as they are usually well known.


References:

1. Cannesson M, Desebbe O, Rosamel P, et al. Pleth variability index to monitor the respiratory variations in the pulse oximeter plethysmographic waveform amplitude and predict fluid responsiveness in the operating theatre. Br J Anaesth 2008; 101:200. 

2.  Feissel M, Michard F, Faller JP, Teboul JL. The respiratory variation in inferior vena cava diameter as a guide to fluid therapy. Intensive Care Med 2004; 30:1834. 

3.  Lichtenstein DA, Mezière GA, Lagoueyte JF, et al. A-lines and B-lines: lung ultrasound as a bedside tool for predicting pulmonary artery occlusion pressure in the critically ill. Chest 2009; 136:1014. 

4.  Cho RJ, Williams DR, Leatherman JW. Measurement of Femoral Vein Diameter by Ultrasound to Estimate Central Venous Pressure. Ann Am Thorac Soc 2016; 13:81.