Long term pulmonary artery pressure monitoring in the management of the critically ill.

Detailed experience during prolonged pulmonary artery pressure monitoring (up to 19 days) in 86 seriously ill patients is reviewed. Strict adherence to a protocol developed for insertion and maintenance of Swan-Ganz catheters resulted in successful catheterization of the pulmonary artery in nearly 100% of patients with minimal morbidity. Several technical problems associated with the use of this catheter-monitoring system are described, excessive balloon inflation with resultant misleading, spuriously high pressure measurement being one of the most serious. Most technical problems are avoidable. In the majority of critically ill patients both central venous and pulmonary artery diastolic pressures proved to be in-accurate estimates of pulmonary artery wedge pressure (PAW). PAW was a useful adjunct in the assessment of intravascular volume and hemodynamic alterations in these patients. The Swan-Ganz catheter serves for other functions including collection of mixed venous blood for cardiac output determination and injection of contrast material for small vessel angiography. Measurement of pulmonary artery wedge pressures should be routinely included in the sequential hemodynamic evaluation of most patients sufficiently ill to be hospitalized in an intensive care unit.