Precision and accuracy of intraoperative temperature monitoring. Anesth Analg 1983; 62:211-4.Using tympanic membrane (TM) temperature as a standard for core temperature, we quantitated the accuracy and precision of seven other temperature monitoring sites during anesthesia, namely, the nasophaynx, esophagus, rectum, bladder, axilla, forehead, and great toe. Accuracy was quantitated as the difference between TM temperature and the temperature at each of the other sites; precision was quantitated as the correlation between TM temperature and the temperature at each of the other sites. Results indicate that the accuracy of measurements made using the great toe, forehead, and axilla is less than the accuracy of measurements made using the nasophaynx, esophagus, bladder, and rectum. Precision of measurements made using the nasopharynx, esophagus, and bladder is greater than the precision at the axilla, forehead, and rectum, and much higher than the precision at the great toe. Measurements of body temperature using the nasopharynx, esophagus, and bladder are recommended for intraoperative use as providing the best combination of accuracy and precision.The performance of any measuring instrument is defined in terms of its precision and accuracy. Precision quantitates the variability of a measurement when compared to another measurement and accuracy quantitates the difference between a measurement and the true value (1). Using tympanic membrane temperature as the true value for body core temperature (2), we sought to assess the precision and accuracy of several commonly employed sites for measurement of body temperature. Materials and MethodsAfter obtaining approval from the institutional Human Subjects Committee and informed written consent from study participants, 56 patients (21 men and 35 women) scheduled for noncardiac surgery were studied. Patients with a history of problems with the tympanic membrane or middle ear were excluded.Temperatures were measured with a Mon-a-therm temperature monitor (Model 6000, Mon-a-therm, Inc, St Louis, MO) that was calibrated before each use. The following disposable thermocouple probes were This study was supported in part by a grant from the Mon-atherm, lnc, St. Louis, Missouri.

To ascertain the immediate effects of coronary artery bypass grafting on regional myocardial function, intraoperative transesophageal two-dimensional echocardiograms were obtained in 20 patients using a 3.5 MHz phased array transducer at the tip of a flexible gastroscope. Cross-sectional images of the left ventricle were obtained at multiple levels before skin incision and were repeated serially before and immediately after cardiopulmonary bypass. Using a computer-aided contouring system, percent systolic wall thickening was determined for eight anatomic segments in each patient at similar loading conditions (four each at mitral and papillary muscle levels). Of the 152 segments analyzed, systolic wall thickening improved from a prerevascularization mean value (+/- SEM) of 42.7 +/- 2.9% to a postrevascularization mean value of 51.6 +/- 2.6% (p less than 0.001). Thickening improved most in those segments with the worst preoperative function (p less than 0.001). Chest wall echocardiograms obtained 8.4 +/- 2.3 days after operation showed no deterioration or further improvement in segmental motion compared with transesophageal echocardiograms obtained after revascularization. Thus: regional myocardial function frequently improves immediately after bypass grafting, with increases in regional thickening being most marked in those segments demonstrating the most severe preoperative dysfunction, and this improvement appears to be sustained; and in some patients, chronic subclinical ischemic dysfunction is present which can be improved by revascularization.

Between 4 and 10% of patients with renal cell carcinoma have tumor involving the inferior vena cava and many of these patients have suprahepatic extension. In patients with intracaval neoplastic extension precise definition of the superior aspect of the tumor thrombus is critical. Transabdominal ultrasonography, computerized tomography (CT), magnetic resonance imaging (MRI) and inferior venacavography are all currently used to evaluate the inferior vena cava in these patients. Intraoperative transesophageal echocardiography was used to image the inferior vena cava in 5 patients with renal cell carcinoma and intracaval neoplastic extension. In each patient transesophageal echocardiography correctly revealed the superior extent of tumor thrombus. In 3 patients tumor thrombus was found at a higher level by transesophageal echocardiography than by CT, MRI and inferior venacavography. In all patients tumor imaging by transesophageal echocardiography correlated well with the gross appearance and extent of tumor found at operation. Echocardiography also documented the absence of residual gross tumor after resection. Transesophageal echocardiography was also useful to assess left ventricular function. Although each of these patients had a pulmonary artery catheter as well transesophageal echocardiography can be useful in situations when right atrial tumor thrombus prevents right heart catheterization. This small series demonstrates that intraoperative transesophageal echocardiography can accurately evaluate the extent of tumor thrombus and provides a means to assess myocardial function complementary to the pulmonary artery catheter.