What is the Vd/Vt ratio calculated for a 7-year-old following surgery with current monitoring data of FiO2 0.40?

To determine the Vd/Vt ratio for a patient, particularly in a pediatric setting, it is important to understand what the ratio signifies. The Vd/Vt ratio refers to the fraction of tidal volume that is represented by dead space ventilation (Vd), which does not participate in gas exchange, compared to the total tidal volume (Vt).

In a healthy child, the normal Vd/Vt ratio typically ranges from about 20% to 30%. However, certain conditions like surgery, especially if there were complications or if the child is experiencing altered lung mechanics, can potentially elevate this ratio. Given that the FiO2 is monitored at 0.40, providing supplemental oxygen may indicate that the child is receiving additional support for oxygenation, but it does not directly alter the Vd/Vt ratio itself.

When the calculation yields a result of 20%, it signifies a scenario where the child's mechanics are relatively efficient post-surgery, with only a portion of the tidal volume being utilized for dead space. This is consistent with expectations immediate post-operative recovery where dead space ventilation might be increased slightly but still remains within a typical range.

Thus, selecting 20% aligns well with physiological expectations following surgery and illustrates that while some ineff