Biomedical subjects
Publications and source records attributed to M J Polonius.
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Some new predictors of postoperative psychosis in open-heart surgery have been identified in a multifactorial study of somatic and psychological factors: Somatic predictors are lower body weight, higher blood levels of urea nitrogen and creatinine, preoperative use of tranquilizers, especially in patients with double valve replacement or congenital heart disease and preoperative cerebral embolism in mitral valve disease. Bypass-time has not proved to be a valid predictor. Psychological predictors are distress provoked by severity and duration of illness, repeated delay of surgery as well as the manner of psychological coping with the illness.
A brief history of the development of coronary heart surgery is presented. Modern methods include the aorto-coronary bypass using saphenous vein graft or the thoracic internal artery, and the resection of ventricular aneurysm. The own experience with a group of 262 patients revealed a total mortality of 11,4%. Selected indication, improved surgical technique and postoperative care changed coronary surgery during the recent years into a routine method. The operative risk is characterized by the anatomical location of the occlusive artery disease as well as by the left ventricular function. But even in the group with high surgical risk the operative treatment is justified since life expectancy under conservative therapy is limited. In a group with 17 late death the main cause was due to cardiac insufficiency. In the group of survivors approximately 84% of the bypass were patent after an average period of 18 months.
From 1970 until 1975 single mitral valve replacement was carried out in 162 patients using Björk-Shiley disc prostheses. The surgical mortality (within 30 days postoperatively) was 9.3% (n=15). Out of these 15 patients 9 died due to myogenic cardiac insufficiency. 21 patients with "Low-output-Syndrome" due to myogenic insufficiency however survived. The improvement of intraoperative myocardial protection since 1972 (using hypothermia and cardioplegic induced cardiac arrest) reduced the frequency of myogenic cardiac insufficiency to 1%. Unrelated to the above mentioned we saw in 18.5% of all patients after ECC-procedures a temporary "Low-output-Syndrome" after the 3rd postoperative day due to pericardial effusion.
From 1972 to 1974 524 patients underwent surgery with extra corporal circulation. 83 (15,8%) patients had to be postoperatively ventilated for a prolonged period or reintubed after a symptomfree interval due to anticipated or manifested complications. 31 (37%) out of these expired. There was no death due to the prolonged ventilation itself, shown by the group, in which the causes for the above treatment were others but respiratory failure or insufficiency. All patients of this group survived. Indications, technique and results are described and discussed.
In 1972 and 1973 there have been 698 (351 with ECC) cardiovascular surgical procedures. 29 cases of renal insufficiency were seen in this group, 15 requiring peritoneal dialysis. There were only two survivors in the latter group. However none died due to renal insufficiency. The indication, technique, complications, results are discussed in detail.
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The risk of open heart surgery can be lowered by combination of different methods of myocardial protection. 1. Cardioplegia with a potassium free Mg-1-aspartate and Procaine-solution (Cardioplegin). 2. Coronary perfusion after ischemia longer than 35-40 minutes in case of excessive left ventricular hypertrophy or failure. 3. Hypothermia. Surface cooling gives an additional safety if coronary perfusion is not ideal possible in case of multiple coronary stenoses. For patients with this dispositions a continuous coronary perfusion with cardioplegic solution might be advisable, as it was presented by Gercken in his paper. This method was used three times already in human, but is still in an experimental stage.