Pulmonary Sequelae after Artificial Ventilation

Abstract

Intermittent positive pressure ventilation (IPPV) really began in Denmark in the polio epidemic of 1953 when medical students hand-bagged dozens of patients with bulbar involvement. Lassen’s dramatic paper (1) of this reads more like a battle report than a scientific article and converted these tentative steps to the use of IPPV devices as the major method of mechanical support in respiratory failure. This substantially increased the therapeutic range for mechanical ventilators as negative pressure devices were limited in the pressures that they could apply to the lung. It then became possible to treat diffuse parenchymal disease with hypoxic respiratory failure: the two paradigms being infant and adult respiratory distress syndrome (IRDS and ARDS). Now high oxygen concentrations were being forced into lungs with a nonuniform distribution of compliance and created two new problems: pulmonary barotrauma and oxygen toxicity. In a major collaborative study on ARDS it was concluded that over half the patient deaths on conventional mechanical ventilators, were attributed to complications of the ventilator itself; either due to barotrauma or oxygen toxicity (2). A similar situation probably applies to infants with the additional problem of ventilator-induced chronic lung damage, which has no clear counterpart in adult patients.