the load placed on the respiratory muscle pump exceeds its capacity,
ventilatory failure ensues. This situation is ultimately fatal unless
either medical therapy is able to reduce the load or mechanical
ventilation is instituted. Preexisting neuromuscular disease is
sometimes the primary indication for mechanical ventilation, but the
more usual indications, at least in the general ICU setting, are
nonneurologic causes, for example, trauma, surgery, and sepsis, in
patients not previously known to have neurologic disease.