Correspondence: Dr J. Wahren, Department of Clinical Physiology, Huddinge Hospital, S-141 86 Huddinge, Sweden.ponent of respiratory failure. Moreover, the concentration of energy-rich compounds in muscle rose significantly as the patients responded to treatment, which emphasizes the importance of adequate nutritional therapy in this disorder.

Resuscitation was attempted in 319 patients brought to hospital with cardiac arrest during a 5‐year period. Primary successful results were achieved in 50 patients (15.7%). Twelve patients were long‐term survivors (3.4%), 10 of whom had normal brain function, whereas 2 had mild cerebral dysfunction. To improve prognostication in patients with initially successful resuscitation, Bayes' theorem was applied using 4 clinical findings after 24 hours' treatment: reactions to painful stimuli, pupillary size, light reactions and BP. Bayes' theorem as well as coma depth after 24 hours gave valuable information regarding individual prognosis.

Twenty-nine patients, divided into three groups: 1) chronic obstructive pulmonary disease; 2) acute or chronic pulmonary disease with left heart failure; 3) respiratory insufficiency after peritonitis, pancreatitis, and/or sepsis, were studied during respirator treatment with regard to gas exchange, breathing mechanics and central circulation. The dead space ventilation was somewhat greater in group 1 than in the other groups. The alveolar-arterial oxygen tension difference was least in group 1, greater in group 2 and extremely high in group 3. Neither dynamic compliance of the thorax nor inspiratory resistance showed any significant differences between the groups. The cardiac output had the highest values in group 3. The venous admixture was generally small in group 1 and extremely large in group 3. The pulmonary artery pressures were highest in group 2. Three variables proved to be valuable when assessing the prognosis of a patient: a large venous admixture; a large alveolar-arterial oxygen tension difference, and a high pulmonary artery pressure indicated a less favourable prognosis.

No abstract

The immediate effects of intermittent positive pressure breathing (IPPB) on air were studied in seven patients (age 55-73 years) with advanced chronic obstructive lung disease (COLD) and with chronic respiratory insufficiency. Dynamic lung compliance was reduced by an average of 25% by IPPB, while inspiratory resistance increased by 40%. Distribution of inspired gas, as determined by nitrogen washout, became more even with IPPB. Respiratory frequency was not altered, whereas total ventilation increased by 25% during IPPB and PaCO2 was reduced. Oxygen uptake was reduced by 6%. PaO2 did not change during IPPB but had decreased by an average of 20% 10 minutes after IPPB and then slowly improved; PaCO2 did not change after IPPB. The pressures in the right atrium, pulmonary artery, and in pulmonary wedge position all increased approximately 2 mm Hg (approximately 2 cm H2O) with IPPB, while intrathoracic pressure rose on an average by 5 cm H2O, the transmural pressures thus being lowered during IPPB. The pulmonary vascular resistance was not significantly altered by IPPB, whereas the systemic vascular resistance rose 25%. Cardiac output was reduced approximately 20% and venous admixture almost 50%.