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Transesophageal Doppler (TED) monitoring provides continuous, noninvasive monitoring of cardiac output by measurement of aortic flow velocities. Because of the effects on aortic flow dynamics resulting from atherosclerosis, aortic cross-clamping, and wide variations in arterial blood pressure, the validity of TED monitoring during aortic surgery is unresolved. The authors prospectively evaluated a second-generation TED cardiac output monitor in 42 patients undergoing aortic reconstructive surgery. Four hundred eighty-nine simultaneous measurements of TED and thermodilution cardiac output were obtained. Transesophageal Doppler measurements were highly correlated to thermodilution measurements (R = 0.94); however, Bland-Altman analysis revealed a moderate error in the TED measurements (2 SD of the bias = 1.4 L/min). Trending analysis showed that TED monitoring accurately tracked changes in thermodilution cardiac output. Placement of an aortic cross-clamp resulted in significant reductions in the accuracy of Doppler measurements. Arterial blood pressure variations did not systematically affect the accuracy of the transesophageal technique. Limitations of TED monitoring, including a difficult calibration procedure, poor performance during aortic cross-clamping, and the need for probe repositioning, suggest further development is warranted.

We evaluated our experience with 846 consecutive transesophageal echocardiography (TEE) intraoperative monitoring procedures performed between November 1989 and July 1991. TEE frequency was 36 +/- 11 per month (range 16-55) and represented 69.8% of cardiac valve surgery cases, 40.2% of coronary artery bypass graft cases, and 2.2% of total operative caseload. Major patient complications consisted of transient vocal cord paresis and ingestion of glutaraldehyde-disinfectant solution. Minor complications consisted of a chipped tooth (one case) and pharyngeal abrasions (three cases). The Quality Assurance (Q/A) Program evaluated both record keeping and quality of imaging, as judged by cardiologist echocardiographer reviewers. The percentage of completion for each Q/A indicator was as follows: medical record documentation, 88%; database form annotation, 94%; and provision of videotape recording, 91%. TEE database forms were analyzed further in terms of the percentage of fields completed. Completion scores were 73%. The following scoring system was utilized for videotape evaluation by the cardiologists: 1 = excellent; 2 = good; 3 = poor. The median grade for both two-dimensional echocardiography and color flow Doppler (CFD) examinations was 2. Poor quality images (grade 3) were present in 15.2% of two-dimensional echocardiography and 20.3% of color flow Doppler examinations, and disproportionately associated with 4/26 attendings. Supplemental audit of the cardiology reviewers performance demonstrated 569/846 videotapes showed no objective evidence of review. The cardiology reviewer forms of the remaining 277 videotapes were evaluated in terms of the percentage of fields completed. The completion score was 56%. These data suggest the need for formal Q/A for intraoperative TEE, both for anesthesiologists and reviewing cardiologists.

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