A description has been given of the use of tracheostomy and IPPR in the treatment of twenty-five cases suffering from respiratory and circulatory complications after open-heart surgery. In patients suffering from respiratory abnormalities, results were good. In those with a derangement of the circulation results were poor. However, it was concluded that therapy in this group is often justified. Although arterial blood gas determinations are of value, the decision to use artificial ventilation must be based on a consideration of the history and clinical state in addition to the biochemical data.