Transnasal transesophageal echocardiography: a modified application mode for cardiac examination in ventilated patients

In 42 endotracheally intubated patients, we examined the utility of a miniaturized monoplane probe for transnasal transesophageal echocardiography (TEE). Transnasal TEE was prospectively evaluated in 26 deeply and 16 mildly sedated patients receiving topical anesthesia with lidocaine jelly 2%. The patients with deep sedation were additionally examined with transoral monoplane and multiplane TEE. Transnasal esophageal insertion of the TEE probe was successfully performed in 90% of patients. Endotracheal malpositioning was corrected in two patients. Nasal bleeding required treatment in another patient. Topical anesthesia was adequate in 82% of mildly sedated patients. Left ventricular short- and four-chamber long-axis views of good quality were obtained with transnasal (transoral) monoplane TEE in 76% (81%) and 92% (96%) of patients (differences not significant). Compared with conventional multiplane TEE, transnasal monoplane TEE missed diagnoses in 19% of patients. The relative error (mean +/- SEM) of quantification with transnasal TEE was <9% +/- 2% for ventricular diameters and <7% +/- 2% for cross-sectional area measurements, with a bias of 0.5 +/- 3.8 cm2 and 0.1 +/- 2.4 cm2 (mean +/- 2 SD) for left ventricular end-diastolic and end-systolic short-axis areas. The relative error in measuring intracardiac flow velocities was >40%, but systolic to diastolic peak velocity ratios at the valvular site were determined with an error <4% +/- 3%. Transnasal monoplane TEE can be performed even in mildly sedated patients with an endotracheal tube without further need for analgesia or sedation. The technique is as useful as conventional transoral TEE to image standard tomographic planes for quantification, but it is less suited for comprehensive echocardiographic diagnosing. Implications: Transnasal insertion of a miniaturized monoplane transesophageal echocardiography (TEE) probe was studied in endotracheally intubated patients. Nasal passage was well tolerated even by patients with only mild sedation. Imaging quality was similar to conventional transoral monoplane TEE with larger transducers, but technical restraints cause a deficit in complete cardiac diagnosing obtained with multiplane TEE.