There are many situations where altitude can have a significant effect on a casualty suffering, either from decompression sickness or other pressure related trauma that would necessitate an evacuation at low level. This is often not possible where high terrain is involved, or where flights at low levels would very considerably increase fuel utilization and reduce aircraft range. A Hyperlite solves the problem, as the patient can be maintained at a low positive pressure, without even the need for breathing oxygen at high dosages throughout the flight.