Transoesophageal two-dimensional echocardiographic evaluation of anaesthetic effects on left ventricular function

Utilization of echocardiography in Intensive Care Units: results of an online survey in Germany

BACKGROUND

In patients with hemodynamic instability echocardiography has been recommended as the preferred modality to evaluate the underlying pathophysiology. However, due to the fact that recent scientific data on the utilization of echocardiography in German Intensive Care Units (ICU) are scarce, we sought to investigate current practice.

METHODS

A structured, web-based, anonymized survey was performed from May until July 2015 among members of the German Interdisciplinary Association of Critical Care and Emergency Medicine (DIVI) consisting of 14 questions. Descriptive data analysis was performed.

RESULTS

One hundred four intensivists participated in the survey. Two-thirds of participants (66%) used echocardiography regularly for hemodynamic monitoring and stated that it changed the therapy in 26-50% of the cases irrespective of the time performed after ordering the examination. Transthoracic (TTE) were more frequently used than transesophageal (TEE) examinations. Twenty-six percent of the participants held an echocardiography certificate with a formal examination, 27% completed a structured training without an examination and almost half of the questioned ICU personnel (47%) did not complete a comprehensive training.

CONCLUSIONS

The results of this survey demonstrate a widespread utilization of echocardiography as part of routine diagnostic on frequent number of operative ICUs. However, there might be a lack of structured echocardiographic training especially for anesthesiologists.

Dobutamine aggravates haemodynamic deterioration induced by pleural effusion: A randomised controlled porcine study

BACKGROUND

Pleural effusion is a common finding in critically ill patients and may contribute to circulatory instability and the need for inotropic support.

OBJECTIVE

We hypothesised that dobutamine would affect the physiological determinants preload, afterload, contractility and changes of inferior vena cava characteristics during experimental pleural effusion.

DESIGN

A randomised, controlled laboratory study.

SETTING

Animal laboratory, conducted from March 2013 to May 2013.

ANIMALS

Twenty-four Landrace and Yorkshire female piglets (21.3 ± 1.7 kg).

INTERVENTION

Twenty piglets were included in the analyses. After inducing bilateral pleural effusion (30 ml kg), the piglets were block randomised to either incremental dobutamine infusion (n = 10) or control (n = 10).

MAIN OUTCOME MEASURES

Ultrasonographic measures of left ventricular end-diastolic area, left ventricular afterload, left ventricular fractional area change and inferior vena cava diameter and distensibility were used to assess the basic physiological effect of incremental dobutamine administration during experimental pleural effusion.

RESULTS

In the dobutamine group, preload, measured as left ventricular end-diastolic area, decreased from 11.3 ± 2.0 cm after creation of the pleural effusion to 8.1 ± 1.5 cm at a dobutamine infusion rate of 20 μg kg min (P < 0.001). In the same period, central venous pressure and the expiratory diameter of the inferior vena cava decreased from 9 ± 3 to 7 ± 4 mmHg (P < 0.001) and from 1.1 ± 0.2 to 0.9 ± 0.1 cm (P = 0.008), respectively.

CONCLUSION

In a porcine model of pleural effusion, dobutamine affected basic haemodynamic determinants substantially by decreasing left ventricular preload. Changes in central venous pressure and inferior vena cava characteristics were minimal, discouraging their use as indices of preload. This study underlines the significance of evaluating basic haemodynamic determinants to avoid inappropriate, potentially harmful treatment.

Transthoracic echocardiography in the perioperative setting

PURPOSE OF REVIEW

A need for further assessment of patients in the perioperative setting and an increasing availability of ultrasonography equipment have facilitated the diffusion of ultrasonography and lately focused transthoracic echocardiography (TTE) in anesthesiology practice. This review will discuss the possible use of focused TTE in the perioperative setting and provides an update on present and future perspectives.

RECENT FINDINGS

Several studies focusing on patient management and diagnostic accuracy of perioperative, focused TTE, have been published recently. Several multidisciplinary guidelines addressing use and educational aspects of focused ultrasonography are available, yet guidelines focusing solely on the use in the perioperative setting are lacking.

SUMMARY

Hemodynamically significant cardiac disease or pathophysiology can be disclosed using TTE. Focused TTE is feasible for perioperative patient management and monitoring and will be an inevitable and indispensable tool for the anesthetist. Future research should focus on the outcome of perioperative TTE performed by anesthetists, using rigorous study designs and patient-centered outcomes such as mortality and morbidity.

New pocket echocardiography device is interchangeable with high-end portable system when performed by experienced examiners

BACKGROUND

Cardiovascular status is a crucial determinant in the pre-operative assessment of patients for surgery as well as for the handling of patients with acute illness. We hypothesized that focus-assessed transthoracic echocardiography (FATE) could be performed with the subject in the semi-recumbent position. The aim was also to test whether the image quality of Vscan is interchangeable with a conventional high-quality portable echocardiography system. Furthermore, we evaluated the time needed to achieve an interpretable four-chamber view and to complete a full FATE examination.

METHODS

Sixty-one subjects were included. All subjects were examined in accordance with the FATE protocol in the semi-recumbent position on two different systems: the novel Vscan pocket device and the high-quality portable Vivid i system. Two evaluations were performed. In group A (n=30), the focus was on image quality. In group B (n=31), the focus was on the time consumed.

RESULTS

Group A: All patients (100%) had at least one image suitable for interpretation and no significant difference in image quality (P=0.32) was found between the two different systems. Group B: The mean value for the total time consumed for a full FATE was 69.3 s (59.8-78.8) on the Vscan and 63.7s (56.7-70.8) on the Vivid i, with no significant difference among the scanners (P=0.08).

CONCLUSION

The Vscan displays image quality interchangeable with larger and more expensive systems. The apparatus is well suited for performing a FATE examination in a 1-day surgery setting and could very well also be applicable in almost any situation involving patients with acute illness.

Transoesophageal echocardiographic monitoring during paediatric cardiac surgery: obtainable information and feasibility in 532 children

BACKGROUND

We hypothesized that transoesophageal echocardiography (TOE) performed by the anaesthesiologists would be beneficial for monitoring purposes during paediatric cardiac surgery. We present the results for the first 5 years in 532 consecutive children.

METHODS

The probe was successfully inserted in 99% of cases and remained in the oesophagus for 211 min on average (range 10-555 min).

RESULTS

Insignificant valve leak, single- or biventricular failure and volume depletion were the most common new findings due to TOE. Changes in inotropic strategy and volume replacement were the most frequent interventions. In 45% of the cases, new information was disclosed and, in a total of 8% of cases, decisive information was provided. Except for tracheal extubation in one child who was uneventfully reintubated, no severe complications were identified.

CONCLUSIONS

These data stress the safety and ease of performing TOE in children undergoing cardiac surgery. There is evidence for benefit from TOE findings to potentially enhance the therapeutic basis.

Rapid atrial pacing for detecting provokable demand ischemia in anesthetized patients

A stress test that can be performed intraoperatively might be valuable for cardiac risk stratification in patients needing urgent noncardiac surgery and for early evaluation of coronary reserve in patients undergoing aortocoronary bypass surgery. Therefore, we evaluated the sensitivity and safety of rapid atrial pacing combined with electrocardiography and transesophageal echocardiography for inducing and detecting provokable demand ischemia in 20 anesthetized patients with multivessel coronary artery disease. Rapid atrial pacing induced ST segment changes or new segmental wall motion abnormalities (SWMA), which were defined as evidence of induced ischemia in 15 of the 20 patients. Unexpectedly, the new SWMA normalized during the first beat after abrupt cessation of pacing in three patients who did not show any ST segment changes. Simultaneously, left ventricular preload was severely decreased during pacing and recovered to baseline immediately when pacing was abruptly discontinued. Rapid atrial pacing was safe in all patients, but the target heart rate could not be achieved because of heart block or arterial hypotension in 4 of the 20 patients. These findings raise the question of whether rapid atrial pacing is the most appropriate approach for inducing provokable demand ischemia in anesthetized patients. However, its potential usefulness for predicting adverse cardiac outcomes has not been evaluated and would require larger studies. In addition, the immediate normalization of new SWMA after abrupt cessation of pacing in some patients calls into question the validity of new SWMA as evidence of myocardial ischemia when left ventricular preload is severely decreased.

Early effects of coronary artery bypass surgery and cold cardioplegic ischemia on left ventricular diastolic function: evaluation by computer-assisted transesophageal echocardiography

OBJECTIVE

Although left ventricular (LV) systolic function undergoes a temporary decrease after cardiopulmonary bypass (CPB) in patients undergoing coronary artery bypass grafting (CABG), data on the effects of CABG and cardioplegic arrest on LV diastolic function are contradictory. The objective of the present study was to further evaluate the effects of CABG and CPB on LV diastolic function.

DESIGN

A prospective study.

SETTING

A multi-institutional investigation at a university hospital.

PARTICIPANTS

20 patients on beta-receptor antagonists, scheduled for CABG and with a preoperative ejection fraction over 0.5.

INTERVENTIONS

Central hemodynamic measurements, transesophageal LV short-axis images, and mitral Doppler flow profiles were obtained before and after volume loading that in turn was performed both before surgical incision and after weaning from CPB.

MEASUREMENTS AND MAIN RESULTS

Heart rate, cardiac output, and peak atrial filling velocity increased; systemic vascular resistance decreased; whereas stroke volume, LV area ejection fraction, deceleration rate and slope of early diastolic filling, time-velocity integral of early diastolic filling, and the ratio between early and atrial peak filling velocity were unchanged post-CPB compared with pre-CPB. LV end-diastolic stiffness that was calculated for each patient pre-CPB and post-CPB using the formula: P = B*eS*A), where P is the LV filling pressure and A is the end-diastolic short-axis area, was unchanged post-CPB compared with pre-CPB.

CONCLUSIONS

Both the active and passive components of LV diastolic function are well maintained shortly after CABG and cardioplegic arrest in patients with a good preoperative systolic LV function.

Utility and limitations of biplane transesophageal echocardiographic automated border detection for estimation of left ventricular stroke volume and cardiac output

Recent echocardiographic ABD algorithms can estimate LV volume on-line from a single long-axis plane. The objective of this study was to assess the capability and limitations of transesophageal ABD to estimate stroke volume and cardiac output in patients before and after coronary artery bypass surgery by correlating these data with simultaneous thermodilution measurements. ABD data were acquired on-line from the transverse-plane four-chamber view and the longitudinal-plane two-chamber view and calculated by automated area-length and Simpson's rule formulas for volume. Thirty-three studies were attempted in 18 patients. Technically adequate ABD data were available in all patients from at least one view. Twenty-two (67%) of 33 studies from the four-chamber view and 27 (82%) of 33 studies from the two-chamber view were technically adequate. Cardiac output by all ABD methods was significantly correlated with thermodilution values (r range 0.72 to 0.89; SEE range 0.48 to 0.55 L/min). The two-chamber view underestimated cardiac output slightly, by an average of 0.4 L/min, whereas the four-chamber view consistently underestimated cardiac output by an average of 1.9 L/min. The area-length and Simpson's rule algorithms produced similar results. Biplane transesophageal ABD is an alternative method for estimating cardiac output; the two-chamber view in particular has potential for on-line volume determination.

Assessment of the immediate effects of cardiopulmonary bypass on left ventricular performance by on-line pressure-area relations

BACKGROUND

Pressure-volume relations have been established as useful measures of left ventricular (LV) performance. Application of these methods to the intraoperative setting have been limited because of difficulties acquiring LV volume data. Transesophageal echocardiographic automated border detection can measure LV cross-sectional area as an index of volume, which can be coupled with pressure data to construct pressure-area loops on-line. The purpose of this study was to evaluate intraoperative LV performance in patients undergoing coronary bypass surgery before and immediately after cardiopulmonary bypass using on-line pressure-area relations.

METHODS AND RESULTS

Studies were attempted in 13 consecutive patients. Simultaneous measures of LV cross-sectional area, LV pressure, and electromagnetic flow probe-derived aortic flow recorded on a computer work station interfaced with the ultrasound system. Pressure-area loops were compared with simultaneous pressure-volume loops constructed from pressure and flow data during inferior vena caval occlusions before and after bypass. Pressure-volume calculations (end-systolic elastance, maximal elastance, and preload-recruitable stroke work) were then applied to pressure-area loops with area substituted for volume data. Changes in stroke force from pressure-area loops were closely correlated with changes in estimates of stroke work from pressure-volume loops for individual patients before bypass (r = .99 +/- .03, SEE = 5 +/- 2%, n = 10) and after bypass (r = .96 +/- .05, SEE = 5 +/- 2%, n = 9). Pressure-area estimates of end-systolic elastance, maximal elastance, and preload-recruitable stroke force decreased significantly from before to after cardiopulmonary bypass in the 7 patients with paired data sets. Load-dependent measures of LV function (stroke volume, cardiac output, and fractional area change) were unchanged after surgery in these same patients.

CONCLUSIONS

Intraoperative pressure-area loops may be acquired and displayed on-line using transesophageal echocardiographic automated border detection and readily analyzed in a manner similar to pressure-volume loops. LV performance was depressed immediately after cardiopulmonary bypass compared with before. On-line pressure-area relations may be clinically useful to assess LV performance in patients undergoing cardiac surgery in whom load and contractility may be expected to vary rapidly.

Comparison of left ventricular function by echocardiographic automated border detection and by radionuclide ejection fraction

Echocardiographic automated border detection can provide on-line estimates of left ventricular cavity area by differentiating blood from tissue backscatter characteristics. The objective of this study was to assess the ability of short-axis measurements of left ventricular cavity area by automated border detection to determine left ventricular function by comparing these measurements to radionuclide measures of ejection fraction in the same patients. Eighty-eight consecutive patients, aged 53 +/- 14 years, underwent automated border detection studies within 2 hours of radionuclide ventriculography. Short-axis imaging with automated border detection was attempted at basal, midpapillary muscle, and apical levels. Maximal left ventricular length was also measured from apical 4- and 2-chamber views by standard imaging. Fractional area change--(end-diastolic area-end-systolic area)/end-diastolic area--was determined at each short-axis level. Volumes and ejection fractions were calculated using: volume = 5/6 (midventricular area).length. Simpson's rule for 3 short-axis measurements was calculated using: volume = (length/12) (5.basal area + 2.mid-area + 4.apical area). Technically adequate automated border detection data could be obtained on 69 patients (78%) at basal and mid-levels, and at all 3 short-axis levels in 66 patients (75%). Correlations with radionuclide ejection fraction were as follows: midventricular fractional area change--R = 0.84, SEE = 12%, y = 0.86 x - 7; area-length ejection fraction--R = 0.89, SEE = 9%, y = 0.96 x - 4; and Simpson's rule--R = 0.91, SEE = 8%, y = 0.89 x + 1.(ABSTRACT TRUNCATED AT 250 WORDS)

On-line estimation of changes in left ventricular stroke volume by transesophageal echocardiographic automated border detection in patients undergoing coronary artery bypass grafting

Echocardiographic automated border detection can determine the interface between blood and myocardial tissue and calculate left ventricular (LV) cavity area in real-time. The objective was to determine if on-line measurements of LV cavity area by transesophageal automated border detection could be used to determine beat-to-beat changes in stroke volume in humans. Studies were attempted on 9 consecutive patients, aged 66 +/- 8 years, undergoing coronary bypass surgery. Stroke volume was measured by electromagnetic flow from the ascending aorta, and LV cavity area was measured at the midventricular short-axis level. Simultaneous area and flow data were recorded on a computer workstation through a customized interface with the ultrasound system. Recordings were performed during baseline apnea and rapid alterations induced by inferior vena caval occlusions before and after cardiopulmonary bypass. Measurements of stroke area (maximal area-minimal area) were correlated with stroke volume for matched beats. Data were available for analysis on 8 of 9 patients before and on 5 patients after cardiopulmonary bypass for 644 beats. Stroke area was closely correlated with stroke volume both before (mean R = 0.94 +/- 0.03, SEE = 0.33 +/- 0.12 cm2) and after (mean R = 0.92 +/- 0.05, SEE = 0.59 +/- 0.81 cm2) cardiopulmonary bypass. The slopes of these stroke area-stroke volume relations were quite reproducible from before to after cardiopulmonary bypass in the same patient but varied between individual patients. Transesophageal automated border detection has potential for on-line estimation of changes in stroke volume in selected patients.

Usefulness of transesophageal echocardiography in the pediatric catheterization laboratory

Transesophageal echocardiography was performed in 51 children (aged 2 to 14 years, mean 4; weight 9 to 50 kg, mean 21) undergoing elective diagnostic or therapeutic cardiac catheterization. The interventional procedures were percutaneous balloon dilation of pulmonary (n = 8) and aortic (n = 2) valve stenosis, percutaneous closure of patent ductus arteriosus (n = 8), and attempted occlusion of Pott's anastomosis by the double umbrella device (n = 1). The diagnostic catheterizations were performed on preoperative children of whom 5 had undergone previous palliative procedures. Precise placement of the balloon across the valve, timing of balloon inflation and deflation according to real-time monitoring of ventricular function and immediate evaluation of results and complications were accomplished with transesophageal monitoring. The exact position of distal and proximal umbrellas of patent ductus occlusive devices was checked on transesophageal imaging and completeness of occlusion controlled on color Doppler. The only relevant information in the preoperative cases was the detection of a septic thrombus in a severely ill patient. With more experience and smaller probes, transesophageal echocardiography may become a new method of monitoring cardiac catheterization also in smaller children where it may reduce duration of the procedure and amount of contrast material.

Comparison of the findings on preoperative dipyridamole perfusion scintigraphy and intraoperative transesophageal echocardiography: implications regarding the identification of myocardium at ischemic risk

The evidence of myocardium at potential ischemic risk on preoperative dipyridamole perfusion scintigraphy was compared with that of manifest ischemia on intraoperative transesophageal echocardiography in 26 patients at high risk of a coronary event undergoing noncardiac surgery. The clinical outcome was also assessed. Induced intraoperative wall motion abnormalities were more common in patients and myocardial segments with, than in those without, a preoperative reversible perfusion defect (both p less than 0.05). Conversely, a preoperative reversible perfusion defect was more common in patients and segments with, than in those without, a new intraoperative wall motion abnormality (both p less than 0.05). Six patients, five with a reversible scintigraphic defect but only three with a new wall motion abnormality, had a hard perioperative ischemic event. Events occurred more often among patients with, than in those without, a reversible perioperative scintigraphic defect (5 [33%] of 15 vs. 1 [9%] of 11) but this difference did not reach significance (p = 0.14), probably owing to the sample size. Intraoperative wall motion abnormalities were all reversible and did not differentiate between risk groups; these findings were possibly influenced by treatment. These preliminary data support the known relation between reversible scintigraphic defects and perioperative events and identify another manifestation of ischemic risk in the relation between reversible scintigraphic defects and induced intraoperative wall motion abnormalities. The value of intraoperative echocardiography in identifying ischemia and guiding therapy in patients with a reversible scintigraphic abnormality should be further assessed.

The effects of intravenous nitroglycerin and isosorbide dinitrate on hemodynamics and myocardial metabolism

Myocardial ischemia before and during coronary artery surgery is significant, because patients who develop perioperative myocardial ischemia have an increased incidence of postoperative myocardial infarctions. Thus, the prevention of ischemic episodes is of great importance. This study was undertaken to (1) compare the effects of intravenous nitroglycerin (NTG) with isosorbide dinitrate (ISDN); (2) investigate if the continuous infusion of nitrates had beneficial effects on cardiac performance and metabolism; and (3) compare the control of blood pressure with the nitrates versus halothane during a standardized anesthetic. Twenty-one patients participated in the study, and all had the following: a radial arterial catheter, peripheral venous catheter, 7F pulmonary artery catheter, and Baim coronary sinus flow catheter. The study was carried out in the prebypass period beginning with awake measurements of baseline parameters, and ending after median sternotomy. The patients were divided into three groups: group 1 received an infusion of NTG; group 2 received an infusion of ISDN; and group 3, the control, received neither nitrate, but halothane was added to control hemodynamics. Measurements were made at the following time intervals: (1) baseline; (2) after 5 minutes of the nitrate infusions while awake (groups 1 and 2); (3) after induction of anesthesia, laryngoscopy, and intubation; and (4) after median sternotomy. In groups 1 and 2, the nitrates were infused at 0.1 mg/kg/h for 5 minutes. Thereafter, blood pressure control and treatment of episodic hypertension were achieved by alteration of the rate of nitrate infusions, or, in group 3, by 0.5% to 2% of inspired halothane.(ABSTRACT TRUNCATED AT 250 WORDS)