Fig. 3.

There was a marked linear (y = 2.06x + 56.80; r² = 0.71) increase in mechanical ventilation prevalence over the 20-year period in the university hospital medical wards (black line), but not MICU (gray line). Vertical gridlines show January of each year. Most years there was a seasonal pattern on the medical wards, with peak ventilator use during the winter. Seasonality analysis (insert) shows winter peaks in the medical wards (black line) but not the MICU (dotted line) or GICU (gray line)