Critique of intermittent mandatory ventilation.

Kirby and Downs are to be congratulated for introducing a technique that has greatly extended the principles of the old Engström ventilator. IMV permits diagnostic distinction and therapeutic choice between lung distention, for mechanical improvement and oxygen exchange, and mechanical ventilation for pH homeostasis. They have stimulated great interest on the part of manufacturers and clinicians. Factual physiological support is still relatively slim, hypotheses greatly outstripping their supporting data. Much of the existing data are as yet either poorly based or, in one or two instances, in error. Where data do exist, their clinical importance is frequently unclear--effects on cardiac output being a good example. The obvious popularity of this technique certainly justifies its further study, and I look forward to seeing the results. I hope that, if studies being carried out in our own intensive care unit are subject to a similar degree of criticism, my resilience will equal that of the authors of these very interesting chapters.