Andrew Maslow

Accuracy of Transesophageal Echocardiography for Identifying Left Atrial Thrombi: A Prospective, Intraoperative Study

Two-dimensional echocardiography is the noninvasive di agnostic technique of choice for identifying intracardiac thrombi. Left ventricular thrombi, a complication of myocardial infarction and dilated cardiomyopathy, are reasonably well visualized by conventional transthoracic echocardiography, which has surgery- and autopsy-documented sensitivity of 77% to 95% [1, 2]. However, two-dimensional transthoracic echocardiographic identification of left atrial thrombi is less successful because of the posterior location of the left atrium and frequent difficulty in imaging the atrial appendage. The sensitivity of transthoracic echocardiography for detecting left atrial thrombi is only 39% to 63% [3-5], with more limited success for identifying thrombi in the left atrial appendage. Even with modified views [6], the left atrial appendage may be visualized in less than 20% of patients [7]. Transesophageal echocardiography is a recently introduced, moderately invasive diagnostic imaging technique that allows superior visualization of posterior structures such as the left atrium and the atrial appendage. Transesophageal echocardiography is frequently done in the search for atrial thrombi among patients presenting with acute thromboembolism [8, 9]. It has also been used to exclude atrial thrombi before procedures that are considered to be associated with a higher risk for thromboembolism if atrial thrombi are present, such as percutaneous balloon mitral valvuloplasty [10, 11] and cardioversion [12, 13]. Although small surgical series [7, 14] have suggested that the positive predictive value of transesophageal echocardiography is high, no large, consecutive, intraoperative series have been reported. We determined the accuracy of transesophageal echocardiography for identifying and excluding left atrial thrombi by doing intraoperative transesophageal studies in patients who were having cardiac surgery and in whom direct visualization of the left atrial contents was planned. Methods Patients The study sample consisted of 231 consecutive adult patients who had transesophageal echocardiographic examination before elective cardiac surgery between 1 October 1989 and 25 August 1995. Visualization of the left atrial contents was planned as part of the surgical procedure. Patients included 128 women and 103 men (mean age SD, 64 13 years). The indications for repair or replacement of the mitral valve included rheumatic mitral valve disease (86 patients), mitral valve prolapse (71 patients), ischemic mitral regurgitation (30 patients), prosthetic valve dysfunction (22 patients), endocarditis (11 patients), cardiomyopathy (3 patients), and radiation-induced mitral valve injury (1 patient). Seven additional patients were having excision of a left atrial myxoma. Eighty-three patients (36%) were experiencing atrial fibrillation at the time of transesophageal study, and 46 additional patients (20%) had a history of atrial fibrillation. Four patients were experiencing a paced rhythm and 144 patients, a sinus rhythm. Thirty-nine patients (17%) had a history of thromboembolism, and 106 patients (46%) were receiving warfarin during at least part of the month before surgery. Transesophageal Echocardiography Transesophageal echocardiography was done after induction of general anesthesia and sternotomy using a commercial 5.0-MHz monoplane (48 patients) or biplane (69 patients) probe or a 5.0/3.5-MHz multiplane probe (114 patients) and a Sonos 1000, 1500, or 2500 echocardiograph unit (Hewlett Packard Co., Medical Products Division, Andover, Massachusetts). The left atrial appendage was initially viewed in the horizontal (0-degree) plane with the tip of the probe slightly flexed; the probe was gently withdrawn until the bifurcation of the pulmonary artery was visualized. Initial imaging of the left atrial appendage in the vertical (90-degree) plane was followed by posterior and anterior rotation of the probe until the coronary sinus and aorta were visualized, respectively. Multiplane imaging was done at 0 degrees and 90 degrees as described above, followed by imaging of the left atrial appendage in the horizontal (0-degree) plane and 5- to 10-degree stepwise rotation of the imaging sector from 0 degrees to 180 degrees during continuous visualization of the appendage. An atrial thrombus was reported when at least one observer identified a well-circumscribed, echo-reflective mass that was of different texture than the atrial wall and that had a uniform consistency [15]. Spontaneous echo contrast (a marker of blood stasis) was defined as dynamic smokelike echoes within the atrium [16]. The extent of mitral regurgitation was assessed by color Doppler and graded on a scale of 0 (none) to 3 (severe). Images and Doppler data were recorded on videotape; independent decisions on the presence of a thrombus were made by an observer performing the study in the operating room and by a second observer who reviewed the videotape at a later date without knowledge of the first observers conclusions. Both observers made decisions without knowledge of the patients clinical history. All observers were attending physicians with extensive training and experience in transesophageal echocardiography (> 150 studies) [17]. Nine observers were used, although five observers read 91% of the studies (WJM, 34%; CAW, 21%; PS, 14%; JMH, 14%; ADM, 8%). Transesophageal echocardiographic data on the presence or absence of a thrombus were initially withheld from the surgeon unless they were considered to affect patient care (for example, a mobile thrombus in the body of the left atrium). Two hundred twenty-nine patients were studied during surgery immediately before the initiation of cardiopulmonary bypass. Two patients had elective transesophageal echocardiographic study that showed left atrial appendage thrombus and that was followed within 1 week by mitral valve surgery. Transthoracic Echocardiography Data from conventional transthoracic echocardiographic examinations done within 30 days of surgery were available on 143 patients (62%). Two-dimensional imaging had been done using a Hewlett Packard Sonos 500, 1000, or 1500 combined imaging unit and a Doppler echocardiograph unit equipped with a 2.0- or 2.5-MHz phased-array transducer. The M-mode left atrial dimension was measured in the parasternal long-axis view. We considered ventricular systolic function to be abnormal if evidence suggested global or regional hypokinesis. Surgical Confirmation All patients had cardiotomy under cardiopulmonary bypass, which was done using moderate hypothermia (28 C) and aortic arterial and bicaval venous cannulation under one period of continuous aortic cross-clamping. Cold crystalloid or blood-potassium cardioplegia was administered antegrade, retrograde, or in combination every 15 to 20 minutes. In most patients, the left atrium was then entered through an incision in the interatrial groove. In patients with left atrial myxomas, the left atrium was approached either through the right atrium and atrial septum or through a biatrial incision [18]. The surgeon then visually inspected the body of the atrium and the appendage. If a thrombus was identified, its size and site were recorded. Statistical Analysis All data are expressed as the mean SD. We compared categorical variables using the chi-square test with continuity (Yates) correction for small numbers (Statview II, Abacus Concepts, Berkeley, California). We compared continuous variables using analysis of variance. In all analyses, tests were two-tailed, and a P value of less than 0.05 was considered to be statistically significant. We calculated the sensitivity, specificity, positive and negative predictive values, and accuracy for the identification of left atrial thrombi by transesophageal echocardiography; we used surgical identification or exclusion as the reference standard. The hospital Investigational Review Board approved the study. Results Transesophageal Echocardiography Transesophageal imaging of the body of the left atrium was done in all patients without complication. The left atrial appendage was evaluated in 229 patients. Two patients had previously had cardiac surgery, during which the appendage had been amputated. Transesophageal echocardiography identified 14 left atrial thrombi. Thrombus size ranged from 3 to 80 mm (7 patients had thrombi ranging from 3 to 10 mm, 4 had thrombi ranging from 11 to 20 mm, and 3 had thrombi that were greater than 20 mm). Eleven thrombi were confined to the atrial appendage (Figure 1, top left), 1 thrombus was located within the body of the atrium and extended into the appendage (Figure 1, top right), 1 thrombus was located entirely within the body of the left atrium (Figure 1, bottom left), and 1 thrombus was identified across the interatrial septum (Figure 1, bottom right). Three thrombi were identified with the use of the single-plane transesophageal probe. Five thrombi were identified during biplane probe examination, and 6 thrombi were seen with the use of the multiplane transesophageal probe. Ten of 11 thrombi identified with the biplane or multiplane probe were seen in both the horizontal (0-degree) imaging plane and in the vertical (90-degree) and intermediate imaging planes. One thrombus imaged during biplane examination was visualized only in the vertical plane (Figure 2) and was not apparent in the horizontal (0-degree) plane. Two of 14 left atrial thrombi were identified by only one observer. In both of these cases, thrombi were apparent on transesophageal echocardiography in the distal appendage in patients with rheumatic mitral valve disease, atrial fibrillation, and severe left atrial spontaneous contrast. These thrombi included 1 thrombus observed during monoplane study and another during biplane study. Figure 1. Transesophageal echocardiograms. Panel A. white arrow Panel B. white arrow Panel C. white arrow Panel D. white arrows Figure 2. Transesophageal echocardiograms obtained

Echocardiographic predictors of left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve after mitral valve reconstruction for myxomatous valve disease.

OBJECTIVE To determine predictors of systolic anterior motion and left ventricular outflow tract obstruction (SAM/LVOTO) after mitral valve repair (MVRep) in patients with myxomatous mitral valve disease. BACKGROUND Mechanisms for the development of SAM/LVOTO after MVRep have been described; however, predictors of this complication have not been explored. We hypothesize that pre-MVRep transesophageal echocardiography (TEE) can predict postrepair SAM/ LVOTO. METHODS Using TEE, the lengths of the coapted anterior (AL) and posterior (PL) leaflets and the distance from the coaptation point to the septum (C-Sept) were measured before and after MVRep in 33 patients, including 11 who developed SAM/LVOTO (Group 1) and 22 who did not (Group 2). RESULTS Group 1 patients had smaller AL/PL ratios (0.99 vs. 1.95, p < 0.0001) and C-Sept distances (2.53 vs. 3.01 cm, p = 0.012) prior to MVRep than those in Group 2. Resolution of SAM/LVOTO was associated with increases in AL/PL ratio and C-Sept distance. This reflects a more anterior position of the coaptation point in those who developed SAM/ LVOTO. CONCLUSIONS These data suggest that TEE analysis of the mitral apparatus can identify patients likely to develop SAM/LVOTO after MVRep for myxomatous valve disease. The findings are consistent with the concept that SAM of mitral leaflets is due to anterior malposition of slack mitral leaflet portions into the LVOT. The position of the coaptation point of the mitral leaflets is dynamic and a potential target and end point for surgical designs to prevent SAM/LVOTO post MVRep.

Precardiopulmonary Bypass Right Ventricular Function Is Associated with Poor Outcome After Coronary Artery Bypass Grafting in Patients with Severe Left Ventricular Systolic Dysfunction

Patients with severe left ventricular systolic dysfunction (LVSD) undergoing coronary artery bypass grafting (CABG) have an increased risk for morbidity and mortality. The purpose of this study was to assess the association of pre-CABG right ventricular (RV) function with outcome for patients with severe LVSD. We performed a retrospective evaluation of 41 patients with severe LVSD (left ventricular ejection fraction [LVEF] ≤25%) scheduled for nonemergent CABG. Data were obtained from review of medical records, transesophageal echocardiography tapes, and phone interview. The pre- and post-cardiopulmonary bypass (CPB) LVEF and the RV fractional area of contraction (RVFAC) were calculated by using intraoperative transesophageal echocardiography. Group 1 patients had an RVFAC ≤35% (n = 7), whereas Group 2 patients had RVFAC >35% (n = 34). The durations of mechanical ventilation and of intensive care unit and hospital stays are presented as the median. Pre-CABG LVEF was similar between Groups 1 and 2 (15.8% ± 3.3% versus 17.8% ± 3.9%). Compared with Group 2, Group 1 patients required greater duration of mechanical ventilation (12 days versus 1 day;P < 0.01), longer intensive care unit (14 versus 2 days;P < 0.01) and hospital (14 versus 7 days;P = 0.02) stays, had a more frequent incidence and severity of LV diastolic dysfunction, and had a smaller change in LVEF immediately after CPB (4.1% ± 8.3% versus 12.5% ± 9.2%;P = 0.03). All Group 1 patients died of cardiac causes within 2 yr of surgery; five died during the same hospital admission. Three Group 2 patients died: one of colon cancer at 18 mo after CABG and two of cardiac causes 24 and 48 mo after surgery. A fourth patient was awaiting cardiac transplantation 4 yr after surgery. The remaining Group 2 patients were New York Heart Association Classification I or II. For patients with severe LVSD undergoing CABG, pre-CPB RV dysfunction was associated with poor outcome. Patients with RVFAC >35% had a relatively uneventful perioperative course and good long-term survival, whereas patients with RVFAC ≤35% had a poor early and late outcome. Assessment of RV function is useful to further assess the risk of CABG.

Protective versus Conventional Ventilation for Surgery: A Systematic Review and Individual Patient Data Meta-analysis.

Background:Recent studies show that intraoperative mechanical ventilation using low tidal volumes (VT) can prevent postoperative pulmonary complications (PPCs). The aim of this individual patient data meta-analysis is to evaluate the individual associations between VT size and positive end–expiratory pressure (PEEP) level and occurrence of PPC. Methods:Randomized controlled trials comparing protective ventilation (low VT with or without high levels of PEEP) and conventional ventilation (high VT with low PEEP) in patients undergoing general surgery. The primary outcome was development of PPC. Predefined prognostic factors were tested using multivariate logistic regression. Results:Fifteen randomized controlled trials were included (2,127 patients). There were 97 cases of PPC in 1,118 patients (8.7%) assigned to protective ventilation and 148 cases in 1,009 patients (14.7%) assigned to conventional ventilation (adjusted relative risk, 0.64; 95% CI, 0.46 to 0.88; P < 0.01). There were 85 cases of PPC in 957 patients (8.9%) assigned to ventilation with low VT and high PEEP levels and 63 cases in 525 patients (12%) assigned to ventilation with low VT and low PEEP levels (adjusted relative risk, 0.93; 95% CI, 0.64 to 1.37; P = 0.72). A dose–response relationship was found between the appearance of PPC and VT size (R2 = 0.39) but not between the appearance of PPC and PEEP level (R2 = 0.08). Conclusions:These data support the beneficial effects of ventilation with use of low VT in patients undergoing surgery. Further trials are necessary to define the role of intraoperative higher PEEP to prevent PPC during nonopen abdominal surgery.

Association between driving pressure and development of postoperative pulmonary complications in patients undergoing mechanical ventilation for general anaesthesia: a meta-analysis of individual patient data.

BACKGROUND Protective mechanical ventilation strategies using low tidal volume or high levels of positive end-expiratory pressure (PEEP) improve outcomes for patients who have had surgery. The role of the driving pressure, which is the difference between the plateau pressure and the level of positive end-expiratory pressure is not known. We investigated the association of tidal volume, the level of PEEP, and driving pressure during intraoperative ventilation with the development of postoperative pulmonary complications. METHODS We did a meta-analysis of individual patient data from randomised controlled trials of protective ventilation during general anesthaesia for surgery published up to July 30, 2015. The main outcome was development of postoperative pulmonary complications (postoperative lung injury, pulmonary infection, or barotrauma). FINDINGS We included data from 17 randomised controlled trials, including 2250 patients. Multivariate analysis suggested that driving pressure was associated with the development of postoperative pulmonary complications (odds ratio [OR] for one unit increase of driving pressure 1·16, 95% CI 1·13-1·19; p<0·0001), whereas we detected no association for tidal volume (1·05, 0·98-1·13; p=0·179). PEEP did not have a large enough effect in univariate analysis to warrant inclusion in the multivariate analysis. In a mediator analysis, driving pressure was the only significant mediator of the effects of protective ventilation on development of pulmonary complications (p=0·027). In two studies that compared low with high PEEP during low tidal volume ventilation, an increase in the level of PEEP that resulted in an increase in driving pressure was associated with more postoperative pulmonary complications (OR 3·11, 95% CI 1·39-6·96; p=0·006). INTERPRETATION In patients having surgery, intraoperative high driving pressure and changes in the level of PEEP that result in an increase of driving pressure are associated with more postoperative pulmonary complications. However, a randomised controlled trial comparing ventilation based on driving pressure with usual care is needed to confirm these findings. FUNDING None.

The hemodynamic effects of methylene blue when administered at the onset of cardiopulmonary bypass.

Hypotension occurs during cardiopulmonary bypass (CPB), in part because of induction of the inflammatory response, for which nitric oxide and guanylate cyclase play a central role. In this study we examined the hemodynamic effects of methylene blue (MB), an inhibitor of guanylate cyclase, administered during cardiopulmonary bypass (CPB) to patients taking angiotensin-converting enzyme inhibitors. Thirty patients undergoing cardiac surgery were randomized to receive either MB (3 mg/kg) or saline (S) after institution of CPB and cardioplegic arrest. CPB was managed similarly for all study patients. Hemodynamic data were assessed before, during, and after CPB. The use of vasopressors was recorded. All study patients experienced a similar reduction in mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) with the onset of CPB and cardioplegic arrest. MB increased MAP and SVR and this effect lasted for 40 minutes. The saline group demonstrated a persistently reduced MAP and SVR throughout CPB. The saline group received phenylephrine more frequently during CPB, and more norepinephrine after CPB to maintain a desirable MAP. The MB group recorded significantly lower serum lactate levels despite equal or greater MAP and SVR. In conclusion, administration of MB after institution of CPB for patients taking angiotensin-converting enzyme inhibitors increased MAP and SVR and reduced the need for vasopressors. Furthermore, serum lactate levels were lower in MB patients, suggesting more favorable tissue perfusion.

Three-Dimensional Echocardiographic Assessment of Changes in Mitral Valve Geometry After Valve Repair

BACKGROUND Application of annuloplasty rings during mitral valve (MV) repair has been shown to significantly change the mitral annular geometry. Until recently, a comprehensive two-dimensional echocardiographic evaluation of annular geometric changes was difficult owing to its nonplanar orientation. In this study, an analysis of the three-dimensional intraoperative transesophageal echocardiographic evaluation of the MV annulus is presented before and immediately after repair. METHODS We performed three-dimensional geometric analysis on 75 patients undergoing MV repair during coronary artery bypass graft surgery for mitral regurgitation or myxomatous mitral valve disease. Geometric analysis of the MV was performed before and immediately after valve repair with full rings and annuloplasty bands. The acquired three-dimensional volumetric data were analyzed in the operating room. Specific measurements included annular diameter, leaflet lengths, the nonplanarity angle, and the circularity index. Before and after repair data were compared. RESULTS Complete echocardiographic assessment of the MV was feasible in 69 of 75 patients (92%) within 2 to 3 minutes of acquisition. Placement of full rings resulted in an increase in the nonplanarity angle or a less saddle shape of the native mitral annulus (137 +/- 14 versus 146 +/- 14; p = 0.002. By contrast, the nonplanarity angle did not change significantly after placement of partial rings. CONCLUSIONS Mitral annular nonplanarity can be assessed in the operating room. Application of full annuloplasty rings resulted in the mitral annulus becoming more planar. Partial annuloplasty bands did not significantly change the nonplanarity angle. Neither of the two types of rings restored the native annular planarity.

Inhaled albuterol, but not intravenous lidocaine, protects against intubation-induced bronchoconstriction in asthma

BackgroundThe ability of intravenous lidocaine to prevent intubation-induced bronchospasm is unclear. The authors performed a prospective, randomized, double-blind, placebo-controlled trial to test the ability of intravenous lidocaine and inhaled albuterol to attenuate airway reactivity after tracheal intubation in asthmatic patients undergoing general anesthesia. MethodsSixty patients were randomized to receive either 1.5 mg/kg intravenous lidocaine or saline, 3 min before tracheal intubation. An additional 50 patients were randomized to receive 4 puffs of inhaled albuterol or placebo 15–20 min before tracheal intubation. Anesthesia was induced with propofol. Immediately after intubation and at 5-min intervals, transpulmonary pressure and airflow were recorded, and lower pulmonary resistance (RL) was calculated. Isoflurane was administered after the initial two measurements to assess reversibility of bronchoconstriction. A bronchoconstrictor response to intubation was defined as RL greater than or equal to 5 cm H2O · l−1 · s−1 in the first two measurements after intubation and RL subsequently decreasing by 50% or more after isoflurane. ResultsThe lidocaine and placebo groups were not different in the peak RL before administration of isoflurane (8.2 cm H2O · l−1 · s−1vs. 7.6 cm H2O · l−1 · s−1) or frequency of airway response to intubation (lidocaine 6 of 30 vs. placebo 5 of 27). In contrast, the albuterol group had lower peak RL (5.3 cm H2O · l−1 · s−1vs. 8.9 cm H2O · l−1 · s−1;P < 0.05) and a lower frequency of airway response (1 of 25 vs. 8 of 23;P < 0.05) than the placebo group. ConclusionsInhaled albuterol blunted airway response to tracheal intubation in asthmatic patients, whereas intravenous lidocaine did not.

Transoesophageal echocardiography during scoliosis repair: comparison with CVP monitoring

PurposeAccurate haemodynamic assessment during surgical repair of scoliosis is crucial to the care of the patient. The purpose of this study was to compare transoesophageal echocardiography (TEE) with central venous pressure monitoring in patients with spinal deformities requiring surgery in the prone position.MethodsTwelve paediatric patients undergoing corrective spinal surgery for scoliosis/kyphosis in the prone position were studied. Monitoring included TEE, intra-arterial and central venous pressure monitoring (CVP). Haemodynamic assessment was performed prior to and immediately after positioning the patient prone on the Relton-Hall table. Data consisted of mean arterial blood pressure (mBP), heart rate (HR), CVP, left ventricular end-systolic and end-diastolic diameters (LVESD and LVEDD respectively) and fractional shortening (FS). Right ventricular (RV) function and tricuspid regurgitation (TR) were assessed qualitatively. Analysis was performed using descriptive statistics, Student’s t test, sign rank, and correlation analysis.ResultsThere was an increase in CVP (8.7 mmHg to 17.7 mmHg;P <.01), and decreases in LVEDD (37.1 mm to 33.2 mm;P <.05), and mean blood pressure (75.0 mmHg to 65.7 mmHg;P <.05) when patients were placed in the prone position. Fractional shortening, LVESD, and HR did not change from the supine to the prone position. Right ventricular systolic function and tricuspid regurgitation were unchanged.ConclusionThese data indicate that the CVP is a misleading monitor of cardiac volume in patients with kyphosis/scoliosis in the prone position. This is consistent with previous studies. In this clinical situation, TEE may be a more useful monitoring tool to assess on-line ventricular size and function.RésuméObjectifL’évaluation hémodynamique précise pendant la correction chirurgicale d’une scoliose est déterminante pour les soins donnés au patient. Le but de l’étude actuelle était de comparer l’échographie transoesophagienne (ETO) au monitorage de la pression veineuse centrale chez les patients souffrant de déformations rachidiennes nécessitant une chirurgie en décubitus ventral.MéthodesDouze patients pédiatriques devant subir, en décubitus ventral, une chirurgie de correction pour une scoliose ou une cyphose ont été étudiés. Le monitorage comprenait l’ETO, la mesure de la pression intra-artérielle et de la pression veineuse centrale (PVC). Lévaluation hémodynamique a été faite avant et immédiatement après l’installation du patient en décubitus ventral sur la table Relton-Hall. Les données comportaient la tension artérielle moyenne (TAm), la fréquence cardiaque (FC), la PVC, les diamètres ventriculaires gauches télosystolique et télodiastolique (DVGTS et DVGTD respectivement) et le raccourcissement fractionnaire (RF). La fonction du ventricule droit (VD) et la régurgitation tricuspidienne (RT) ont été évaluées qualitativement. L’analyse a été réalisée à partir de statistiques descriptives, du test t de Student, du test de rang et de l’analyse de corrélation.RésultatsIl y a eu un accroissement de la PVC (de 8,7 mmHg à 17,7 mmHg;P <,0l), et une diminution du DVGTD (de 37,1 mm à 33,2 mm;P < 0,05) et de la tension artérielle moyenne (de 75,0 mmHg à 65,7 mmHg;P < 0,05) quand les patients ont été placés en décubitus ventral. Le raccourcissement fractionnaire, le DVGTS et la FC n’ont pas été modifiés lors du changement de position, de la position couchée au décubitus ventral. La fonction systolique du ventricule droit et la régurgitation tricuspidienne n’ont pas changé.ConclusionCes résultats indiquent que la PVC n’est pas un moniteur fiable du volume cardiaque chez les patient souffrant de cyphose ou de scoliose, placés en décubitus ventral. Cela correspond aux études antérieures. Dans cette situation clinique, l’ETO peut être un outil de surveillance plus utile pour une évaluation en ligne de la taille et de la fonction ventriculaires.

Pulsed wave Doppler measurement of cardiac output from the right ventricular outflow tract.

Doppler ultrasound can be used to measure cardiac output (CO).Intraoperative Doppler cardiac output (DCO) by transesophageal echocardiography (TEE) has been studied using blood flow velocity from the left ventricular outflow tract (LVOT), the mitral valve (MV), and the main pulmonary artery (MPA). The purpose of this study was to compare DCO, measured from a relatively new TEE view of the right ventricular outflow tract (RVOT), with thermodilution cardiac output (TDCO). We also compared changes in DCO from the RVOT to changes in TDCO. A 5.0/3.7 MHz multiplane TEE probe was placed in 45 adult cardiac surgical patients undergoing general anesthesia. Patients were excluded if there was greater than mild tricuspid valve insufficiency. From the transgastric view, at approximately 110-140 degrees, the RVOT was imaged. DCO was calculated from 1) the time-velocity integral (TVI) using pulse wave (PW) Doppler, 2) the area of the RVOT (measured in early systole using the diameter (pi (D/2)2) of the RVOT at the level of the PW Doppler sample volume), and 3) the heart rate. Simultaneous TDCO was performed by a separate examiner. The RVOT was imaged satisfactorily in 84% of patients (38/45). The mean bias between DCO and TDCO was -0.01 L/min (2 SD +/- 0.45 L/min; n = 38). There was good correlation between DCO and TDCO (R2 = 0.97). Changes in TDCO and changes in DCO were compared in 15 patients. The mean bias between changes in DCO and changes in TDCO was 0.04 L/min (2 SD +/- 0.66 L/min). Analysis of the changes in DCO and TDCO showed good correlation (R2 = 0.96). We conclude that there is a good correlation between DCO measured from the RVOT and TDCO. This technique permits cardiac output measurement without the necessity of placing a pulmonary artery catheter, and it also provides a method of evaluating RVOT blood flow. (Anesth Analg 1996;83:466-71)