On-line monitoring of mixed venous oxygen saturation after cardiothoracic surgery.

On-line monitoring of MVo2 sat. in vivo by means of fibreoptic reflectometry was studied in 19 patients as to its predictive value during the postoperative course after thoracotomy for periods up to 60 hours. In all but one of the 10 patients with MVo2 sat. less than 65% for at least one hour complications occurred. A fall of MVo2 sat. of more than 5% or a value below 60% predicted a period of hypotension in six patients. In two of them this coincided with a period of ventricular arrhythmias. In those with MVo2 sat. greater than 65% no postoperative complications such as arrhythmias, shock, respiratory dysfunction or oliguria took place.