Hemodynamic waveform detection from pulmonary artery catheters in the ICU

We systematically evaluated whether routine pulmonary artery catheterization and the standard recording systems used in the ICU allowed physicians to detect right atrial pressure (RAP) and pulmonary artery wedge pressure (PAWP) waveform components. Fifty-seven patients requiring pulmonary artery catheterization were studied. Standard 7.5 French (Fr), VIP(TM) (venous infusion port) Swan-Ganz® pulmonary artery catheters (PAC) were used in all patients along with standard pressure tubing, transducers, and either of two types of Hewlett-Packard strip-chart recording systems for simultaneous ECG and PAC waveform recording. The waveforms were later analyzed by four investigators, blinded to diagnosis, who formed a consensus. In the RAP waveform recording, a, c, and v waves were detected in 80%, 28%, and 50% of the patients, respectively. In the PAWP waveform recording, a and v waves were detected in 44% and 28% of the patients, respectively. The data were analyzed to determine whether the ability to detect waveform components was associated with cardiac history, hemodynamic variables, or the sensitivity of the waveform strip-chart recorder. Only the sensitivity of the waveform recorder was significantly associated with the ability to detect waveforms. Hemodynamic waveforms cannot be distinguished in a significant number of patients by physicians using the standard PAC and recording systems used in the ICU setting. Increased recorder sensitivity will enhance the detection of waveform components.