The necessity for following certain physiological functions of a patient undergoing heart-lung surgery is well known.1-3 At Stanford University Hospital we have, over the past several years, evolved certain techniques for accomplishing this which we feel will be of interest to other workers in this and similar fields.
Figure 1 is a diagrammatic representation of the floor plan and the personnel involved. Functions which are usually monitored include the EKG, arterial pressure, inferior vena caval pressure (via the long saphenous vein), and superior vena caval pressure. In addition, when hypothermia is employed, blood temperature and body temperature are also followed. These functions are deemed to be an irreducible minimum consistent with the welfare of the patient undergoing open-heart surgery. Other functions, such as venous and arterial oxygen saturation, blood pH,4 respiratory and pump-oxygenator carbon dioxide levels, and atrial and ventricular pressures, are sometimes determined when indicated but are