Figure 1.

The physiological explanation for the changes in stroke volume and IVC diameter caused by mechanical ventilation. RV right ventricle, LV left ventricle, SV_max⁡ and SV_min⁡ maximum and minimum stroke volume, RAP right atrial pressure, IAP intraabdominal pressure, IVC D _max⁡ and IVC_min⁡ maximum and minimum inferior vena cava diameter during the cycle. ^aThe pulmonary transit time represents the time taken for blood to travel through the pulmonary circulation. ^bSV is the product of the velocity-time integral (area under the Doppler signal curve) and the diameter of the vessel at the point the reading was taken.