Transesophageal Doppler Research Articles

Correlation, agreement and concordance of cardiac output estimated by transthoracic ultrasound and transesophageal Doppler with pulmonary artery thermodilution in anesthetized cats

ObjectiveTo characterize the correlation, agreement and concordance of cardiac output (CO) measured with transthoracic ultrasound and the correlation and concordance of aortic blood flow (ABF) minute distance (MD) measured by transesophageal Doppler with CO measured by pulmonary artery thermodilution (PATD) in cats. Study designExperimental study. AnimalsA group of six healthy male neutered cats, aged 2–8 years and weighing 5.3 ± 0.3 kg. MethodsCats were anesthetized with isoflurane in oxygen. CO was measured by PATD (COPATD) and transthoracic echocardiography (COECHO). ABF MD was measured using an esophageal Doppler flow probe aligned with descending ABF. All measurements were made under three conditions: dexmedetomidine (20 μg kg–1) intravenously; atipamezole (200 μg kg–1) intramuscularly and atropine (20 μg kg–1) intravenously as needed to achieve a minimum heart rate of 140 beats minute–1; and dopamine (20 μg kg–1 minute–1) intravenously in that order. Correlation between COPATD and COECHO, and COPATD and Doppler MD was evaluated using repeated measures correlation. Agreement between COPATD and COECHO was evaluated using Bland–Altman method. Differences between consecutive pairs of CO measurements were calculated for concordance analysis. ResultsCorrelation between COPATD and COECHO and between COPATD and MD was significant (p < 0.001), with correlation coefficients greater than 0.92. A bias of > 27% and upper limits of agreement of 66% were found between COPATD and COECHO. Concordance rate with COPATD was 76–80% for COECHO and 72% for MD. Conclusions and clinical relevanceEchocardiographic methods for the measurement of CO showed poor agreement and concordance with PATD. MD showed poor concordance with PATD. As such, these methods cannot be used as an alternative to PATD nor can they appropriately track changes in CO in anesthetized cats.

Evaluation of transpulmonary indicator dilution and transesophageal Doppler flow meter for cardiac output measurement in anesthetized cats

Evaluation of transpulmonary indicator dilution and transesophageal Doppler flow meter for cardiac output measurement in anesthetized cats

Development of an in vitro platform for transesophageal echocardiographic and color Doppler hemodynamic assessments of left atrial appendage occlusion devices

Abstract Introduction Device-related thrombus (DRT) remains a significant complication after left atrial appendage occlusion (LAAO) and is associated with device position. Clinical prospective study of the influence of device position on DRT is cumbersome. Purpose To establish an in vitro bench test platform that allows visual, transesophageal echocardiographic and color Doppler hemodynamic assessments of left atrial appendage occlusion devices. Methods Based on a mock circulatory system, an in vitro platform was developed to create pathophysiological environment and left atrium wall motion under atrial fibrillation condition. Results LAAO devices could be visualized in the left atrium phantom model using transesophageal echocardiography and color Doppler measurement of local blood velocity at LAAO devices were proven to be capable. Deep implantations resulted in uncovered left upper pulmonary vein ridges. In comparison to ostium-fitted device positions, deep implantations were associated with reduced velocity of blood and the local velocity in the "cul-de-sac" remained lower than the critical threshold of 0.2 m/s. Conclusions An in vitro platform was developed that allows transesophageal echocardiographic and color Doppler hemodynamic assessments of left atrial appendage occlusion devices.

Abstract 15834: The Utility of Intra-Operative Coronary Doppler Profiles in Predicting Early and Late Major Adverse Cardiovascular Events After Arterial Switch Operation

Introduction: Coronary artery transfer is the most important technical point in the arterial switch operation (ASO). Intra-operative echocardiography identifies aberrancies in coronary artery Doppler profiles guiding immediate surgical management. Objective: We sought to determine whether abnormal intra-operative coronary artery Doppler profiles are associated with major adverse cardiovascular events (MACE; death, transplantation, heart failure, arrhythmia, need for coronary re-intervention) following ASO at 30-days, 5 &amp; 10 years. Methods: Single centre retrospective review of patients undergoing ASO between 2009 - 2022. Transesophageal or epicardial intra-operative coronary artery Doppler profiles were analysed. Patient variables were abstracted from records. Freedom from MACE was estimated using Kaplan-Meier methods. Results: 347 patients were included. Coronary anatomy was usual (1LCx2R) in 237 (68%), single sinus ostia in 24 (7%), intramural in 14 (4 %). Overall 30-day MACE was 11.2% [8.3%, 15.1%], increasing to 25% [12.1, 47.4%] with single sinus ostia &amp; 35.7% [16.7%, 65.7%] with intramural. Overall 5 &amp; 10-year MACE was 16.5% [12.9, 20.9%], 33.8% [18.5%, 56.4%] with single sinus ostia &amp; 50.0% [27.8%, 77.1%] with intramural. A higher probability of MACE was seen with coronary Doppler reverse flow, absence of normal pattern (Table 1) and a higher peak velocity (Figure 1). Overall 30-day mortality was 1.2% [95%CI 0.4%, 3.0%] and at 5 &amp; 10 years was 6.5% [4.3%, 9.8%]. Conclusions: Intra-operative abnormal coronary artery Doppler profiles during ASO may identify those at highest risk of early and late adverse events, guiding follow-up surveillance strategies.

Invasive Monitoring in the Intensive Care Unit

The purpose of monitoring of the patient in an intensive care unit (ICU) is to improve patient care, like bringing about a change in the treatment or transfer of the patient to a step-down unit. Monitoring also shows the extent of compliance with a formulated standard of care or the degree of deviation from the expected standard of care. The monitoring used for a patient admitted to an ICU can be invasive or noninvasive. Invasive monitoring in an ICU includes arterial blood pressure, transesophageal Doppler, central venous pressure (CVP) measurement, pulmonary artery catheterization, arterial blood gas (ABG) analysis and measurement of intracranial pressure (ICP) and intra-abdominal pressure (IAP). Monitoring of the physiologic parameters depends on the underlying illness of the patient and the availability of equipment in the ICU.

Hemodynamic monitoring and correlation between electrical cardiometry and esophageal Doppler in patients undergoing major abdominal surgery

ABSTRACT Background Transesophageal Doppler (TED) is a minimally invasive monitor that allows continuous hemodynamic variables monitoring. Non-invasive electrical cardiometry (EC) and TED methods added an additional facility to monitor cardiac output (CO) continuously and guide fluid management. The aim of this study was to correlate hemodynamic monitoring between non-invasive EC and Esophageal Doppler (ED) in cases undergoing major abdominal surgery. Methods This prospective observational study was carried out on 35 adult cases, American Society of Anesthesiologists (ASA) physical status II or III, undergoing major abdominal surgery. Esophageal Doppler and EC were attached to the same patient. Parameters measured were hemodynamic parameters. Results Comparison of CO with ICON and ED showed that the ICON mean value ranged from 5.6 to 6.2 l/min, and the ED mean value always ranged from 5.7 to 7.6 l/min with the non-significant difference between the two methods. The precision for the ICON ranged from 15.19 to 17.99% and the precision for ED ranged from 13.39 to 17.08%. At a 15% change in ICON, the ED values’ sensitivity was 72.6% and specificity was 30.9% with AUC 0.505. Conclusion The agreement between CO measured by EC and ED is acceptable. Both monitored trend changes and guided fluid administration in the operation theater. The EC is as accurate as ED in measuring hemodynamics during major abdominal surgery.

Transesophageal Doppler corrected flow time versus plethysmography variability index for goal-directed fluid management in cirrhotic patients during liver resection: a randomized controlled trial

Abstract Background Central venous pressure (CVP) readings are affected by several factors. The need to test the technology of noninvasive or minimal invasive monitoring during liver surgery to guide fluids intake is the focus of this trial. Adult hepatic patients undergoing elective open liver resection were randomized into transesophageal Doppler (TED, n = 20) or plethysmography variability index (PVI, n = 20). PVI blinded to anesthetist in TED group (gp) and vice versa. During dissection, crystalloids were restricted to keep corrected flow time (FTc) parameter of TED &lt; 330 msec or PVI &gt; 14%, otherwise infused at 6 ml/kg/h. Following resection, colloids infused if FTc &lt; 330 msec or PVI &gt; 14% despite crystalloids infusion. Primary aim is to compare TED-corrected flow time (FTc, msec) parameter to PVI (%) for guiding intravenous fluids during liver resection. Secondary to study their correlations and each parameter effect on blood loss and consumption, morbidity and intensive care unit (ICU) stay. Results It is presented as median [IQ]. Volumes of crystalloids and colloids guided by FTc and PVI were not different (p = 0.3, p = 0.1, respectively) despite negligible correlations. Normovolemic existed during dissection despite 2 h of fluids restriction. FTc was 327 (320–341) msec, PVI was 11.50 (11.00–14.00) %, and CVP in TED gp 11.00 (10.00–12.00) vs. 9.00 (9.00–11.50) mmHg in PVI gp, p = 0.2. Blood loss was 1500 (475–2000) ml in TED vs. 950 (675–1925) in PVI, p = 0.5. Patients’ % in need for blood transfusion and volumes in TED vs. PVI gps were similar: red blood cells: 30%, 350 (350–350) vs. 40%, 525 (350–700) ml, and p = 0.2. Plasma is 20%, 200 (200–300) vs. 40%, and 400 (200–400) ml, p = 0.3. There was no difference in nausea, vomiting, or ICU stay, (p &gt; 0.05). Conclusions Volume of fluids guided by PVI was not different from that by TED, despite lack of correlation. Transfusion-free dissection was possible for a significant number of patients with normovolemia. Trial registration PACTR201808140151322 (www.pactr.org)

Acute Respiratory Distress Syndrome and Shunt Detection With Bubble Studies: A Systematic Review and Meta-Analysis.

Medical literature analysis and retrieval system online, Excerpta Medica dataBASE, Cochrane Library, and database of abstracts of reviews of effects databases on March 26, 2021. Articles relating to respiratory failure and sonographic shunt detection. Articles were independently screened and extracted in duplicate. Data pertaining to study demographics and shunt detection were compiled for mortality and oxygenation outcomes. Risk of bias was appraised using the Joanna-Briggs Institute and the Newcastle-Ottawa Scale tools with evidence rating certainty using Grading of Recommendations Assessment, Development and Evaluation methodology. From 4,617 citations, 10 observational studies met eligibility criteria. Sonographic detection of right-to-left shunt was present in 21.8% of patients (range, 14.4-30.0%) among included studies using transthoracic, transesophageal, and transcranial bubble Doppler ultrasonographies. Shunt prevalence may be associated with increased mortality (risk ratio, 1.22; 95% CI, 1.01-1.49; p = 0.04, very low certainty evidence) with no difference in oxygenation as measured by Pao2:Fio2 ratio (mean difference, -0.7; 95% CI, -18.6 to 17.2; p = 0.94, very low certainty). Intra- and extrapulmonary shunts are detected frequently in ARDS with ultrasound techniques. Shunts may increase mortality among patients with ARDS, but its association with oxygenation is uncertain.

A concise history of echocardiography: timeline, pioneers, and landmark publications.

Echocardiography is less than 70 years old, and many major advances have occurred within living memory, but already some pioneering contributions may be overlooked. In order to consider what circumstances have been common to the most successful innovations, we have studied and here provide a timeline and summary of the most important developments in transthoracic and transoesophageal ultrasound imaging and Doppler techniques, as well as in intravascular ultrasound and imaging in paediatric cardiology. The entries are linked to a comprehensive list of first publications and to a collection of first-hand historical accounts published by early investigators. Review of the original manuscripts highlights that it is difficult to establish unequivocal precedence for many new imaging methods, since engineers were often working independently but simultaneously on similar problems. Many individuals who are prominently linked with particular developments were not the first in their field. Developments in echocardiography have been highly dependent on technological advances, and most likely to be successful when engineers and clinicians were able to collaborate with open exchange between centres and disciplines. As with many other new medical technologies, initial responses were sceptical and introduction into clinical practice required persistence and substantial energy from the first adopters. Current developments involve advances in software as much as in equipment, and progress will depend on continuing collaborations between engineers and clinical scientists, for example to identify unmet needs and to investigate the clinical impact of particular imaging approaches.

Correlation between Doppler Echocardiography and Right Heart Catheterization Assessment of Systolic Pulmonary Artery Pressure in Patients with Mitral Regurgitation: A Prospective Observational Study.

Pulmonary hypertension (PH) is common in patients with left-side valvular diseases, especially with mitral regurgitation (MR). Measurement using pulmonal artery catheter (PAC) is the gold standard to asses pulmonary vascular pressures. During mitral valve surgery echocardiography is routinely used for valvular management and to evaluate pulmonary hemodynamic. The accuracy of echocardiographic measurements is controversial in the literature. We aimed to evaluate the reliability and accuracy of the noninvasive measurement for systolic pulmonary artery pressure (SPAP) using Doppler echocardiography compared to the invasive measurement using PAC in patients presenting with MR undergoing surgery. This prospective observational study evaluated 146 patients with MR undergoing cardiac surgery between 09/2020 and 10/2021. All patients underwent simultaneous SPAP assessment by PAC and transesophageal echocardiography at three different time points: before heart-lung-machine (HLM), after weaning from HLM and at the end of surgery. Mean patients' age was 61 11.5 years, and 51 (35%) patients were female. Most of patients presented with severe MR (n = 126; 86.3%) or endocarditis (n = 18; 12.3%). Patients underwent either isolated mitral valve surgery (n = 65; 44.5%) or mitral valve surgery combined with other surgeries (n = 81; 55.5%). Mean SPAP was underestimated by transesophageal echocardiographic measurement in comparison to PAC measurement before HLM (41.9 13.1 mmHg vs. 44.8 13.8 mmHg, p 0.001), after weaning from HLM (37.6 9.3 mmHg vs. 42.4 10.1 mmHg, p 0.001), and at the end of surgery (35.6 9.1 mmHg vs. 39.9 9.9 mmHg, p 0.001). This difference remained within the sub-analysis in patients presented with moderate or severe PH during all the time points. Bland-Altman analysis showed that transesophageal echocardiographic measurement underestimate SPAP in comparison to PAC as these two approaches are significantly different from one another. In patients presented with MR, transesophageal Doppler echocardiography could asses the presence of PH with high probability. This assessment is however underestimated and the use of PAC in those patients to diagnose, classify and monitor the therapy of PH remains recommended if required.

Pulse Wave Analysis Using the Pressure Recording Analytical Method to Measure Cardiac Output in Pediatric Cardiac Surgery Patients: A Method Comparison Study Using Transesophageal Doppler Echocardiography as Reference Method.

Cardiac output (CO) is a key determinant of oxygen delivery, but choosing the optimal method to obtain CO in pediatric patients remains challenging. The pressure recording analytical method (PRAM), implemented in the MostCareUp system (Vygon), is an invasive uncalibrated pulse wave analysis (PWA) method to measure CO. The objective of this study is to compare CO measured by PRAM (PRAM-CO; test method) with CO simultaneously measured by transesophageal Doppler echocardiography (TEE-CO; reference method) in pediatric patients. In this prospective observational method comparison study, PRAM-CO and TEE-CO were assessed in pediatric elective cardiac surgery patients at 2 time points: after anesthesia induction and after surgery. The study was performed in a German university medical center from March 2019 to March 2020. We included pediatric patients scheduled for elective cardiac surgery with arterial catheter and TEE monitoring. PRAM-CO and TEE-CO were compared using Bland-Altman analysis accounting for repeated measurements per subject, and the percentage error (PE). We included 52 PRAM-CO and TEE-CO measurement pairs of 30 patients in the final analysis. Mean ± SD TEE-CO was 2.15 ± 1.31 L/min (range 0.55-6.07 L/min), and mean PRAM-CO was 2.21 ± 1.38 L/min (range 0.55-5.90 L/min). The mean of the differences between TEE-CO and PRAM-CO was -0.06 ±0.38 L/min with 95% limits of agreement (LOA) of 0.69 (95% confidence interval [CI], 0.53-0.82 L/min) to -0.80 L/min (95% CI, -1.00 to -0.57 L/min). The resulting PE was 34% (95% CI, 27%-41%). With a PE of <45%, PRAM-CO shows clinically acceptable agreement with TEE-CO in hemodynamically stable pediatric patients before and after cardiac surgery.

The Use of Transesophageal Doppler and Central Venous Oxygen Saturation as Predictors of Weaning Success

Weaning individuals from mechanical ventilation (MV) is a challenge to physicians. Respiratory failure is the main reason for weaning failure (WF), but heart failure plays a pivotal role as well. Transesophageal Doppler (TED) is a minimally invasive method of hemodynamic tracking with fewer problems. The study authors evaluated the role of TED in predicting WF. An observational study. A university teaching hospital. Weaning individuals. TED was applied before initiating the spontaneous breathing trial (SBT). Hemodynamic parameters, arterial blood gases, and TED (peak velocity [PV], cardiac output [COP]) were reported while cases were on MV before initiating the SBT, and at the successful completion of SBT. Succeeded (group S) and failed individuals (group F, who needed reintubation within 48 hours) were compared. The sensitivity, specificity, and area under the receiver operating curve were calculated. A subgroup of patients with cardiac comorbidities and impaired cardiac contractility was further analyzed. The authors included 39 critically ill patients for weaning from MV. The reintubation rate was 54.8%. In patients with cardiac morbidity, delta change (dC) in PV and COP as predictors of WF showed 100% sensitivity and specificity, with 18% and 14% cut-offs after initiating the SBT (dC between the beginning and end of the successful SBT), respectively. Central venous oxygen saturation revealed a significant difference between patients with cardiac morbidity and noncardiac patients with lower sensitivity and specificity in the prediction of WF. TED could be a helpful method for the weaning of patients with cardiac morbidity from MV. The dC in PV and COP >18% and >14% were significant predictors of WF in these subjects, respectively.

Predictors of Exercise Capacity in Dilated Cardiomyopathy with Focus on Pulmonary Venous Flow Recorded with Transesophageal Eco-Doppler.

The aim of this study was to clarify the relative contribution of elevated left ventricle (LV) filling pressure (FP) estimated by pulmonary venous (PV) and mitral flow, transesophageal Doppler recording (TEE), and other extracardiac factors like obesity and renal insufficiency (KI) to exercise capacity (ExC) evaluated by cardiopulmonary exercise testing (CPX) in patients with dilated cardiomyopathy (DCM). During the CPX test, 119 patients (pts) with DCM underwent both peak VO2 consumption and then TEE with color-guided pulsed-wave Doppler recording of PVF and transmitral flow. In 78 patients (65%), peak VO2 was normal or mildly reduced (>14 mL/kg/min) (group 1) while it was markedly reduced (≤14 mL/kg/min) in 41 (group 2). In univariate analysis, systolic fraction (S Fract), a predictor of elevated pre-a LV diastolic FP, appeared to be the best diastolic parameter predicting a significantly reduced peak VO2. Logistic regression analysis identified five parameters yielding a unique, statistically significant contribution in predicting reduced ExC: creatinine clearance < 52 mL/min (odds ratio (OR) = 7.4, p = 0.007); female gender (OR = 7.1, p = 0.004); BMI > 28 (OR = 5.8, p = 0.029), age > 62 years (OR = 5.5, p = 0.03), S Fract < 59% (OR = 4.9, p = 0.02). Conclusion: KI was the strongest predictor of reduced ExC. The other modifiable factors were obesity and severe LV diastolic dysfunction expressed by blunted systolic venous flow. Contrarily, LV ejection fraction was not predictive, confirming other previous studies. This has important clinical implications.

Assessing the left atrial appendage thrombus using 3D transesophageal echocardiography and pulse wave doppler

Abstract Background/Introduction In some patients, detecting and visualizing left atrial appendage (LAA) thrombus (especially at fundus level) seems to be challenging. Thus looking for indirect signs such as morphology, size and function may be of use. Purpose Finding echocardiographic signs suggesting presence of LAA thrombus using 3D TEE &amp; pulse wave doppler. Methods We collected data via transesophageal echocardiography (TEE) from different set of patients with diseased heart (valvular especially mitral stenosis, congenital, pre-cardiac conversion for atrial fibrillation). And that by using EPIQ7 echo machine by Phillips. With each patient, we acquired pulse wave doppler determining the maximum (telesystolic) emptying velocity at mid LAA (MEV-LAA), and maximum long axis surface area of LAA (LAA-SA) using Xplan modality or multiplanar reconstruction from gated 3D acquisitions of LAA. Doing so we tried to assess the relationship between LAA thrombus and its morphology (2D/3D) using the 04 shapes classification (windsock, cauliflower, chicken wing, cactus), measuring LAA-SA considering a cutoff of 6cm2 or above a dilated LAA. A MEV-LAA considered diminished if less than 25cm/s. Finally we calculated the ratio of LAA-SA/MEV-LAA. Results We assessed a group of 55 patients. LAA thrombus was visualized in 10 of them. The predominant morphology was windsock 50.9% then equally chicken wing and cauliflower 14.5%, cactus 11%. Thrombus occurred in major part with cauliflower type with 50% of all patients with the same shape. LAA was dilated in 25 patients in whom 7 had LAA thrombus (Se: 70% Sp: 60% PPV: 22%). LAA maximum emptying velocity was reduced in 18 patients in whom 10 had LAA thrombus (Se: 100% Sp: 82.2% PPV: 36%). We found that 7 patients with a ratio LAA-SA/MEV-LAA &amp;lt;1.7 had LAA thrombus (Se: 70% Sp: 97.8% PPV: 47%). Cauliflower morphology has the highest occurrence of thrombus as demonstrated in the literature. LAA-SA is the least reliable criteria associated with LAA thrombus. MEV-LAA is has the most sensible value of the three measurements. The ratio LAA-SA/MEV-LAA seems to have the highest specificity and positive predictive value in terms of association with thrombus (in cauliflower type this ratio seems to be less specific). Some limitations of this study was the limited number of patients assessed, no comparison in terms of sex (LAA size is different in men and women according to literature), sinus rhythm versus atrial fibrillation (LAA maximum emptying velocity), no correlation with CT-scan of LAA concerning dimensions and thrombus. Conclusion 3D transesophageal echocardiography and pulse wave doppler study of the LAA seems to be associated with thrombus formation especially indirect signs and indexed values (ratio LAA-SA/MEV-LAA), that tends to push the diagnostic power of TEE. Promptly this will lead to more investigations on a large scale number of patients in different sub-type groups. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Mustapha Pacha University Hospital Center, department of Cardiology A2 3D TEE of LAA and Mitral prosthesisXplan on LAA, cauliflower type

Left Atrial Appendage Function Assessment by Tissue Doppler Transesophageal Echocardiography in Acute Ischemic Stroke Patients

Background: Strokes due to Cardioembolic causes are the most severe in ischemic stroke subtypes. LAA flow patterns and function could be assessed accurately by TEE. The study aimed to present the importance of Transesophageal echocardiography in the assessment of LAA function and its relation to cardioembolic stroke. Methods: 120 patients were enrolled in the study and were subdivided into 3 subgroups, each group included 40 patients. Group A; patients had a stroke with normal sinus rhythm, Group B; patients had a stroke with atrial fibrillation, and Group C; normal control subjects. The study participants were evaluated by medical history, physical examination, standard 12-leads electrocardiogram, a transesophageal echocardiographic detailed evaluation of the LAA, and brain CT and/or MRI for patients with stroke. Results: both stroke patients with AF and sinus rhythm had significantly higher LAA mean orifice diameter and higher LAA length than control patients, significantly lower mean LAA medial wall tissue Doppler upward and downward motion velocities than control patients and that patients with stroke and AF had significantly lower mean LAA pulsed wave emptying and filling velocities than both patients with stroke and sinus rhythm and control patients. Presence of LAA thrombi, spontaneous echo contrast, and stroke recurrence were higher in stroked AF patients than stroke patients with sinus rhythm. Conclusion: increased LAA orifice diameter, LAA length, and reduced filling and emptying velocities and upward and downward motion velocities of the medial wall of LAA as detected by TEE are associated with stroke and cardio embolization.&#x0D;

Non-invasive methods of cardiac output measurement and their importance in everyday clinical practice: the current state of knowledge

Cardiac output is an important parameter in the evaluation of the patients’ haemodynamic status which can be measured using a number of methods with varying degrees of invasiveness. These include invasive (such as pulmonary artery catheterization, transpulmonary thermodilution, lithium dilution), minimally invasive (catheter-based arterial pressure curve contour analysis, transoesophageal Doppler) and non-invasive (electrical bioimpedance, transthoracic echocardiography, measurement of exhaled CO2, continuous non-invasive blood pressure measurement) techniques. With advances in medicine, the role of non-invasive methods as an alternative to pulmonary artery catheterization continues to grow. The undoubted advantage of non-invasive methods is their safety for the patients and their wide availability. In contrast, invasive methods are characterized by greater measurement precision. It is up to the physician to choose the most appropriate haemodynamic monitoring method depending on the clinical situation. The aim of this article is to discuss non-invasive cardiac output measurement techniques and their application in everyday clinical practice.

The usefulness of the transesophageal Doppler in the anesthetic management of Morgagni hernia repair - A case report

Morgagni hernia in adults is a rare condition and is associated with complications such as recurrent chest infections, respiratory failure and cardiac tamponade. Its correction represents an anesthetic challenge. Intraoperative esophageal Doppler provides important information in real time about the patient’s cardiac function and vascular filling, aiding in decision making by the anesthesiologist. We report a case of a 70–year–old woman, ASA Physical Status–III, and presented with chest pain, dyspnea and hypoxemia. Her chest x-ray revealed opacification of 2/3 of the left hemithorax and 1/2 of the right. Computed tomography confirmed a bilateral Morgagni hernia. The patient underwent immediate corrective surgery. Intraoperative cardiovascular function was monitored with esophageal Doppler. Compression and decompression of thoracic structures produces enormous hemodynamic and respiratory impact. After herniated contents removal it showed an increase in systolic volume and cardiac index and a correction of flow time. Transient arterial hypotension was verified, requiring fluid therapy and vasopressor support. Diaphragmatic defect was corrected and general hemodynamic stabilization was achieved. Patient was discharged asymptomatic. The esophageal Doppler was important in this case because it allowed us to measure fundamental hemodynamic variables in real time, such as cardiac index or systolic volume, and to subsequently act accordingly.&#x0D; Key words: Esophageal; Doppler; Morgagni hernia; Anesthesia&#x0D; Citation: Babo NM, Monteiro MT, Santos AB, Carreira CR. The usefulness of the transesophageal Doppler in the anesthetic management of Morgagni hernia repair - A case report. Anaesth pain intensive care 2021;25(2):206-211. DOI: 10.35975/apic.v25i2.1467 &#x0D; Received: 19 November 2020, Reviewed: 22 December 2020, Accepted: 12 January 2021

Estimation of cardiac output variations induced by hemodynamic interventions using multi-beat analysis of arterial waveform: a comparative off-line study with transesophageal Doppler method during non-cardiac surgery

Multi-beat analysis (MBA) of the radial arterial pressure (AP) waveform is a new method that may improve cardiac output (CO) estimation via modelling of the confounding arterial wave reflection. We evaluated the precision and accuracy using the trending ability of the MBA method to estimate absolute CO and variations (ΔCO) during hemodynamic challenges. We reviewed the hemodynamic challenges (fluid challenge or vasopressors) performed when intra-operative hypotension occurred during non-cardiac surgery. The CO was calculated offline using transesophageal Doppler (TED) waveform (COTED) or via application of the MBA algorithm onto the AP waveform (COMBA) before and after hemodynamic challenges. We evaluated the precision and the accuracy according to the Bland & Altman method. We also assessed the trending ability of the MBA by evaluating the percentage of concordance with 15% exclusion zone between ΔCOMBA and ΔCOTED. A non-inferiority margin was set at 87.5%. Among the 58 patients included, 23 (40%) received at least 1 fluid challenge, and 46 (81%) received at least 1 bolus of vasopressors. Before treatment, the COTED was 5.3 (IQR [4.1–8.1]) l min−1, and the COMBA was 4.1 (IQR [3–5.4]) l min−1. The agreement between COTED and COMBA was poor with a 70% percentage error. The bias and lower and upper limits of agreement between COTED and COMBA were 0.9 (CI95 = 0.82 to 1.07) l min−1, −2.8 (CI95 = −2.71 to−2.96) l min−1 and 4.7 (CI95 = 4.61 to 4.86) l min−1, respectively. After hemodynamic challenge, the percentage of concordance (PC) with 15% exclusion zone for ΔCO was 93 (CI97.5 = 90 to 97)%. In this retrospective offline analysis, the accuracy, limits of agreements and percentage error between TED and MBA for the absolute estimation of CO were poor, but the MBA could adequately track induced CO variations measured by TED. The MBA needs further evaluation in prospective studies to confirm those results in clinical practice conditions.

Central venous pressure monitoring in critical care settings.

Patients who present with acute cardiovascular compromise require haemodynamic monitoring in a critical care unit. Central venous pressure (CVP) is the most frequently used measure to guide fluid resuscitation in critically ill patients. It is most often done via a central venous catheter (CVC) positioned in the right atrium or superior or inferior vena cava as close to the right atrium as possible. The CVC is inserted via the internal jugular vein, subclavian vein or via the femoral vein, depending on the patient and their condition. Complications of CVC placement can be serious, so its risks and benefits need to be considered. Alternative methods to CVC use include transpulmonary thermodilution and transoesophageal Doppler ultrasound. Despite its widespread use, CVP has been challenged in many studies, which have reported it to be a poor predictor of haemodynamic responsiveness. However, it is argued that CVP monitoring provides important physiologic information for the evaluation of haemodynamic instability. Nurses have central roles during catheter insertion and in CVP monitoring, as well as in managing these patients and assessing risks.

A novel method of trans-esophageal Doppler cardiac output monitoring utilizing peripheral arterial pulse contour with/without machine learning approach.

Transesophageal Doppler (TED) velocity in the descending thoracic aorta (DA) is used to track changes in cardiac output (CO). However, CO tracking by this method is hampered by substantial change in aortic cross-sectional area (CSA) or proportionality between blood flow to the upper and lower body. To overcome this, we have developed a new method of TED CO monitoring. In this method, TED signal is obtained primarily from the aortic arch (AA). Using AA velocity signal, CO (COAA-CSA) is estimated by compensating changes in the aortic CSA with peripheral arterial pulse contour. When AA cannot be displayed properly or when the quality of AA velocity signal is unacceptable, our method estimates CO (CODA-ML) from DA velocity signal first by compensating changes in the aortic CSA, and by compensating changes in the blood flow proportionality through a machine learning of the relation between the CSA-adjusted CO and a reference CO (COref). In 12 anesthetized dogs, we compared COAA-CSA and CODA-ML with COref measured by an ascending aortic flow probe under diverse hemodynamic conditions (COref changed from 723 to 7316ml·min-1). Between COAA-CSA and COref, concordance rate in the four-quadrant plot analysis was 96%, while angular concordance rate in the polar plot analysis was 91%. Between CODA-ML and COref, concordance rate was 93% and angular concordance rate was 94%. Both COAA-CSA and CODA-ML demonstrated "good to marginal" tracking ability of COref. In conclusion, our method may allow a robust and reliable tracking of CO during perioperative hemodynamic management.