The impact of intra-operative transoesophageal echocardiography on cardiac surgical practice

The use of transoesophageal echocardiography during cardiac surgery has increased dramatically and it is now widely accepted as a routine monitoring and diagnostic tool. A prospective study was carried out between September 2004 and September 2007, and included all patients in whom intra-operative echocardiography was performed, 2 473 (44%) out of a total of 5 591 cases. Changes to surgery were subdivided into predictable (where echocardiographic examination was planned specifically to guide surgery) and unpredictable (new pathology not diagnosed pre-operatively). A change in the planned surgical procedure was documented in 312 (15%) cases. In 216 (69%) patients the changes were predictable and in 96 (31%) they were unpredictable. The number of predictable changes increased between 2004–5 and 2006–7 (8% vs 13%, p = 0.025). In these cases, intra-operative echocardiography was specifically requested by the surgeon to help determine the operative intervention. This has implications for consent and operative risk, which have yet to be fully determined.     

Transthoracic and transoesophageal echocardiography: a systematic review of feasibility and impact on diagnosis,management and outcome after cardiac surgery

Transthoracic and transoesophageal echocardiography are increasingly used as tools to improve clinical assessment following cardiac surgery. However, most physicians are not trained in echocardiography, and there is no widespread agreement on the feasibility, indications or effect on outcome of transthoracic or transoesophageal echocardiography for patients after cardiac surgery. We performed a systematic review of electronic databases for focused transthoracic and transoesophageal echocardiography after cardiac surgery which revealed 15 full‐text articles. They consistently reported that echocardiography is feasible, whether performed by a novice or expert, and frequently resulted in important changes in diagnosis of cardiac abnormalities and their management. However, most were observational studies and there were no well‐designed trials investigating the impact of echocardiography on outcome. We conclude that both transthoracic and transoesophageal echocardiography are useful following cardiac surgery.     

The safety of intraoperative transesophageal echocardiography: a case series of 7200 cardiac surgical patients

Transesophageal echocardiography (TEE) is an invaluable intraoperative diagnostic monitor that is considered to be relatively safe and noninvasive. Insertion and manipulation of the TEE probe, however, may cause oropharyngeal, esophageal, or gastric trauma. We report the incidence of intraoperative TEE-associated complications in a single-center series of 7200 adult cardiac surgical patients. Information related to intraoperative TEE-associated complications was obtained retrospectively from the intraoperative TEE data form, routine postoperative visits, and cardiac surgical morbidity and mortality data. The overall incidences of TEE-associated morbidity and mortality in the study population were 0.2% and 0%, respectively. The most common TEE-associated complication was severe odynophagia, which occurred in 0.1% of the study population. Other complications included dental injury (0.03%), endotracheal tube malpositioning (0.03%), upper gastrointestinal hemorrhage (0.03%), and esophageal perforation (0.01%). TEE probe insertion was unsuccessful or contraindicated in 0.18% and 0.5% of the study population, respectively. These data suggest that intraoperative TEE is a relatively safe diagnostic monitor for the management of cardiac surgical patients. IMPLICATIONS: The overall morbidity (0.2%) and mortality (0%) rates of intraoperative transesophageal echocardiography (TEE) were determined in a retrospective case series of 7200 adult, anesthetized cardiac surgical patients. The most common source of TEE-associated morbidity was odynophagia (0.1%), which resolved with conservative management. These results suggest that TEE is a safe diagnostic tool for the management of cardiac surgical patients.     

The impact of intraoperative echocardiography on clinical outcomes following adult cardiac surgery

Over the past 30 years, intraoperative echocardiography has become an invaluable diagnostic tool and monitor of cardiac performance for the management of cardiac surgical patients. The essential information provided by intraoperative echocardiography regarding hemodynamic management, cardiac valve function, congenital heart lesions, and great vessel pathology has contributed to its widespread popularity. Numerous investigations have been conducted in an attempt to specifically demonstrate a beneficial impact of intraoperative echocardiography in cardiac surgery. However, there is a relative paucity of data derived from prospective trials in which the use of intraoperative echocardiography has been randomized among various cardiac surgical patient populations to formally ascertain, rather than simply infer, its putative impact on perioperative decision-making and clinical outcomes. Ironically, the popularity of intraoperative echocardiography has imposed ethical limitations on performing randomized trials in patient populations for whom significant benefit has been previously inferred. Nonetheless, significant evidence has been published to support its almost universal acceptance as an important perioperative diagnostic tool and monitor for cardiac surgical patients. This review focuses on the impact of intraoperative echocardiography on clinical outcomes in the more common adult cardiac surgical scenarios, including coronary artery bypass graft surgery, mitral and aortic valve surgery, and in evaluating the intrathoracic aorta.     

Intraoperative transoesophageal echocardiography for paediatric cardiac surgery--an audit of 200 cases

We report out initial experience with intraoperative transoesophageal echocardiography (TOE) in 200 patients undergoing repair of congenital heart disease. Complications associated with probe insertion precluded a full study in 11 patients (5.5%) and included airway obstruction (n = 6), inability to pass the probe (n = 4) and vascular compression (n = 1). The preoperative diagnosis was confirmed by TOE in 176 of 189 cases (93%) with minor variances in 12 (6.3%) and one major variance (additional large muscular ventricular septal defect (VSD)). Unexpected abnormalities not diagnosed preoperatively were found at surgery in four cases (2%) and were all of trivial operative significance. Postoperative studies showed no residual defect in 96 (51%) and trivial or mild residual defects in 72 patients (38%). There were moderate or severe residual defects in 21 cases (11%). Ten cases (5.3%) returned to bypass for further surgery, with eight achieving complete or adequate amelioration. In six of the 10 cases, return to bypass was prompted by the TOE examination alone. There was one re-operation in the postoperative period for a VSD patch dehiscence. Routine TOE offers significant advantages in the management of patients undergoing repair of congenital heart disease, particularly in postoperative assessment. Careful monitoring of perfusion and ventilation is required, particularly during probe insertion in children weighing 5 kg or less.     

The impact of neurophysiological intraoperative monitoring on surgical decisions: a critical analysis of 423 cases

OBJECT: The aim of this observational clinical study was to analyze the impact of neurophysiological intraoperative monitoring (IOM) on the surgical procedure and to assess the benefits of such monitoring. METHODS: Data for 423 patients who underwent neurophysiological IOM with somatosensory evoked potentials and brainstem auditory evoked potentials during neurosurgical procedures were collected prospectively. The patients were classified into one of five groups according to the findings of IOM, the intervention following a monitoring alarm, and the patient's postoperative neurological condition. These groups were as follows: patients with true-positive findings with intervention (42 cases, 9.9%), those with true-positive findings without intervention (42 cases, 9.9%), those with false-positive findings (nine cases, 2.1%), those with false-negative findings (16 cases, 3.8%), and those with true-negative findings (314 cases, 74.2%). Different interventions followed an event identified with monitoring. These interventions were related to dissection in 17 cases, to perfusion pressure in 11, to a limitation of the surgical procedure in five, to vessel clipping in four, to vasospasm in three, and to retraction in one case. In one case the surgical procedure was abandoned. A critical analysis and cautious estimation of the interventions revealed that IOM was helpful in preventing a postoperative deficit in 5.2% of the monitored cases. CONCLUSIONS; For critical analysis of the benefits of IOM one must evaluate not only the findings of IOM and the patient's postoperative neurological condition but also the intraoperative findings and surgical interventions following a monitoring alarm. Evidence is presented that IOM is helpful in preventing a postoperative deficit.     

The effect of routine intraoperative transesophageal echocardiography on surgical management

OBJECTIVE: To assess the effects of routine intraoperative transesophageal echocardiography (TEE) on surgical management of patients undergoing all types of cardiac surgery. DESIGN: Prospective, observational. Setting: A single-institution, clinical investigation, university-affiliated hospital. PARTICIPANTS: Two hundred eighty-three consecutive patients undergoing cardiac surgery. INTERVENTIONS: A comprehensive TEE examination was performed in every patient after the induction of anesthesia. An appropriate surgical plan was then developed. A focused TEE examination was also performed at the conclusion of surgery. Whether or not TEE findings represented new information and whether or not this new information altered surgical management was documented. MEASUREMENTS AND MAIN RESULTS: There were 106 new TEE findings in 87 patients (31%). Half of the new findings involved the mitral valve, and a quarter involved the tricuspid valve. The new TEE information altered surgical management 77 ways in 71 patients (25%). Half of the altered surgical managements involved the mitral valve, and a third involved the tricuspid valve. In 8 patients (3%), TEE information influenced decisions regarding use/nonuse of cardiopulmonary bypass (CPB). In 2 patients, TEE examination after the separation from CPB prompted reinitiation of CPB. In 1 patient, TEE examination after the induction of general anesthesia prompted cancellation of surgery. CONCLUSIONS: The routine use of TEE during cardiac surgery revealed new cardiac pathology in 1 of every 3 patients and led to altered surgical management in 1 of every 4 patients. TEE information also influenced decisions regarding use/nonuse of CPB in 3% of patients. Thus, the authors suggest that intraoperative TEE should be used routinely in all patients undergoing cardiac surgery.     

Assessment of a new ventricular contractile index obtained with transoesophageal echocardiography before and after cardiopulmonary bypass in cardiac surgical patients

We have compared a new contractile index "left ventricular end-systolic wall stress-heart rate-corrected velocity of circumferential fibre shortening (vcfc)" with conventional contractile indices in 13 patients undergoing coronary artery bypass grafting. We generated the slopes of the "end-systolic wall stress-vcfc", "end-systolic wall stress-area" and "peak arterial pressure-area" relationships by altering arterial pressure before and after cardiopulmonary bypass (CPB). In all patients, significant correlations were obtained for end-systolic wall stress-area and peak arterial pressure-area relationships before and after CPB. In all patients, significant inverse linear correlations were obtained for the end-systolic wall stress-vcfc relationship before CPB; however, inverse linear correlation was absent in eight patients after CPB. It may be that the increased afterload had less influence on left ventricular systolic function after CPB as a possible mechanism of loss of the inverse linear correlation in the end-systolic wall stress- vcfc relationship.      

Measurement of cardiac output by transoesophageal echocardiography: a comparison of two Doppler methods with thermodilution

This study assessed the agreement between three methods of cardiac output (CO) measurement, thermodilution, the current clinical standard, and two transoesophageal echocardiographic techniques. Measurements were performed in 37 patients using thermodilution, continuous wave Doppler across the aortic valve and pulsed wave Doppler positioned in the left ventricular outflow tract. The aortic valve area was measured by direct planimetry, and the left ventricular outflow tract area was calculated from its diameter. Weighted least products regression analysis was employed to detect bias, and standard deviation of the difference (SDdiff) was calculated. There was no fixed bias but there was proportional bias between continuous wave Doppler and thermodilution methods (SDdiff 0.92 l/min). There was fixed bias but not proportional bias between pulsed wave and thermodilution methods (SDdiff 1.1 l/min). There was neither fixed nor proportional bias between pulsed wave and continuous wave Doppler methods (SDdiff 1.1 l/min). The transoesophageal Doppler methods described can be clinical alternatives to thermodilution cardiac output measurement.     

Surgical repair of a postendocarditis abscess cavity in the heart guided by intraoperative transoesophageal echocardiography.

A case of aortic prosthetic endocarditis is presented that was complicated by the formation of a cavity in the spatium between the aorta and the roof of the left atrium. At the primary operation this cavity had not been detected. During reoperation the surgeon localized the cavity in the cardioplegic heart, guided by transoesophageal echocardiography.     

Unusual cause of intraoperative hypotension diagnosed with transoesophageal echocardiography in a patient with renal cell carcinoma

Transoesophageal echocardiography (TOE) is not commonly used in the management of non-cardiac cases. We report a case where the use of TOE played a major role in the intraoperative diagnosis and subsequent management of a patient exhibiting severe hypotension whilst undergoing a nephrectomy. The rare diagnosis of a secondary intraventricular tumour would not have been evident with more conventional monitoring techniques.     

The impact of internet and simulation‐based training on transoesophageal echocardiography learning in anaesthetic trainees: a prospective randomised study

With the increasing role of transoesophageal echocardiography in clinical fields other than cardiac surgery, we decided to assess the efficacy of multi‐modular echocardiography learning in echo‐naïve anaesthetic trainees. Twenty‐eight trainees undertook a pre‐test to ascertain basic echocardiography knowledge, following which the study subjects were randomly assigned to two groups: learning via traditional methods such as review of guidelines and other literature (non‐internet group); and learning via an internet‐based echocardiography resource (internet group). After this, subjects in both groups underwent simulation‐based echocardiography training. More tests were then conducted after a review of the respective educational resources and simulation sessions. Mean (SD) scores of subjects in the non‐internet group were 28 (10)%, 44 (10)% and 63 (5)% in the pre‐test, post‐intervention test and post‐simulation test, respectively, whereas those in the internet group scored 29 (8)%, 59 (10)%, (p = 0.001) and 72 (8)%, p = 0.005, respectively. The use of internet‐ and simulation‐based learning methods led to a significant improvement in knowledge of transoesophageal echocardiography by anaesthetic trainees. The impact of simulation‐based training was greater in the group who did not use the internet‐based resource. We conclude that internet‐ and simulation‐based learning methods both improve transoesophageal echocardiography knowledge in echo‐naïve anaesthetic trainees.     

Measurement of cardiac output by transoesophageal Doppler echocardiography in anaesthetized horses: comparison with thermodilution

In order to determine if transoesophageal Doppler echocardiography could be used to estimate cardiac output in anaesthetized horses, we have compared the technique with estimations of cardiac output by thermodilution in eight healthy adult thoroughbreds. Measurements of aortic blood flow velocity were made by high pulse repetition frequency (HPRF) and continuous wave (CW) Doppler echocardiography from a 3.5-MHz transoesophageal probe. Cardiac output was increased during the study by administration of dobutamine, providing a range of cardiac output measurements by thermodilution from 15.0 to 64.4 liter min-1. Estimations derived from CW Doppler overestimated cardiac output compared with thermodilution (bias = 4.0 litre min-1). Estimations from HPRF Doppler echocardiography more closely reflected measurements obtained by thermodilution (bias = 0.7 litre min-1). Limits of agreement between the techniques were similar for both modes of insonation (HPRF = -7.7 to 9.1 litre min-1, CW = -4.9 to 12.8 litre min- 1). There were significant differences in bias between both Doppler techniques and thermodilution for individual horses. As a result, for any individual horse, limits of agreement between the techniques were closer (HPRF = +/- 6.4 litre min-1, CW = +/- 7.6 litre min-1). We conclude that transoesophageal echocardiography provided an alternative, effective and non-invasive method for measurement of cardiac output in anaesthetized horses.      

The usefulness of transesophageal echocardiography during intraoperative cardiac arrest in noncardiac surgery

According to guidelines established by the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists, life-threatening hemodynamic disturbances are classified as a category I indication for the intraoperative use of transesophageal echocardiography (TEE). However, the usefulness of TEE during intraoperative cardiac arrest and its impact on patient management have not been rigorously investigated. Using our departmental TEE database, we identified a population of 22 patients who underwent noncardiac surgical procedures and experienced unexpected intraoperative hemodynamic collapse requiring the initiation of Advanced Cardiac Life Support procedures between the time of induction of general anesthesia and the termination of the surgical procedure. Results of TEE examinations, patient records, detailed operative records, and outcome of patients were reviewed for the utility of TEE to diagnose the etiology of the hemodynamic collapse. Furthermore, the impact on subsequent patient management was evaluated. A primary suspected diagnosis of the underlying pathological process was established in 19 of 22 patients with TEE, including 9 with thromboembolic events, 6 with acute myocardial ischemia, 2 with hypovolemia, and 2 patients with pericardial tamponade. A definitive diagnosis could not be made in 3 patients with TEE. In 18 patients, TEE guided specific management beyond implementation of Advanced Cardiac Life Support protocols, including the addition of surgical procedures in 12 patients. Fourteen patients survived to leave the operating room, and 7 of these patients were eventually discharged from the hospital. Thus, TEE may provide additional diagnostic information in patients with intraoperative cardiac arrest and may directly guide specific, potentially life-saving therapy.     

The effect of transoesophageal echocardiography probe insertion on tracheal cuff pressure

Increased tracheal cuff pressure during mechanical ventilation is associated with reduced mucosal blood flow and ischaemia, as well as postoperative sore throat. We assessed the potential effects of transoesophageal echocardiography probe insertion on the tracheal cuff pressure in patients undergoing cardiac surgery. Using a manometer, the cuff pressure of a high-volume, low-pressure tracheal tube (inner diameter 7.0 mm for women and 7.5 mm for men) was adjusted to 25-30 cm H(2)O before blind insertion of a transoesophageal echocardiography probe. The pressure changes were then recorded for 1 min. After probe insertion, the mean (SD) intra-cuff pressure increased from 27.7 (1.5) to 36.2 (6.4) cm H(2)O (p < 0.001) and was > 35 cm H(2)0 in 17/38 patients (45%). Our results suggest that transoesophageal echocardiography probe insertion may increase the tracheal cuff pressure more than that is generally recommended and therefore the latter should be routinely monitored under such circumstances.     

Cost-effectiveness of routine intraoperative transesophageal echocardiography in pediatric cardiac surgery: a 10-year experience

The beneficial effect of transesophageal echocardiography (TEE) on medical and surgical treatment of children with congenital heart disease has been established. Its cost-effectiveness, however, has not been extensively studied. We analyzed reports of 580 routine TEE examinations performed in our institution between January 1994 and December 2003 in patients younger than 17 yr who required congenital cardiac surgery. After excluding patients who died immediately postoperatively, we identified 33 patients (5.7%) who required a second bypass run on clear-cut indication, i.e., surgical reoperation, and who clearly benefited from TEE findings. An estimate of both fixed and variable costs revealed a savings of 850 to 2655 Swiss francs (CHF) ($690 to $2130 US) per child. This figure undoubtedly underestimates the true cost-effectiveness of routine intraoperative TEE in this setting because we used mostly conservative estimates of the benefits and liberal estimates of the costs. The potential benefits of TEE in hemodynamic monitoring and medical management, in reduction of postoperative morbidity, and in improvement in the quality of life are intangible and were not considered. Although benefits and costs vary according to market conditions, patient populations, surgical practice, and technical expertise with TEE, our analysis demonstrates substantial cost-effectiveness in the use of routine TEE during pediatric cardiac surgery.