Cardiovascular research
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Cardiovascular research · Jun 1985
Comparative StudyIntrathoracic and abdominal pressure variations as an efficient method for cardiopulmonary resuscitation: studies in dogs compared with computer model results.
Intrathoracic pressure variations are currently proposed as the main flow-generation mechanisms in standard and modified cardiopulmonary resuscitation (CPR) techniques. A method of changing pressure within the thorax and abdomen without any degree of heart compression was developed and tested in dogs. Intrathoracic and abdominal pressure waves were induced by cyclic inflation and deflation of the lungs and of perithoracic and periabdominal balloons. ⋯ The average flow in the carotid artery was 21.7 +/- 7.8 ml . min-1, which was 18 +/- 6% of the baseline carotid flow before CPR. Three different factors were found to improve the efficiency of CPR: periabdominal balloon inflation simultaneous with the intrathoracic pressure waves; increased frequency of the pressure waves from 60 to 100 cycles per minute; and inflation of the periabdominal balloon 50 to 100 ms before the thoracic balloon. Blood-gas and acid-base balance analysis during CPR revealed well-oxygenated arterial blood with a marked respiratory alkalosis and a slowly developing metabolic acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)