Zak Hillel

Cardiac output by transesophageal echocardiography using continuous-wave Doppler across the aortic valve.

Background:The use of transesophageal echocardiography for the determination of cardiac output (CO) has been limited to date. We assessed the capability of aortic continuous-wave Doppler transesophageal echocardiography to determine CO (DCO) in a transgastric long-axis imaging plane of the heart by comparing DCO to thermodilution CO (TCO). Methods:DCO was determined in 63 consecutive patients undergoing cardiac surgery. Aortic valve area was obtained from the transverse short-axis view of the valve assuming a triangular shape for the valve orifice. Stroke volume was calculated as the product of velocity–time integral and aortic valve area: stroke volume = velocity–time integral × aortic valve area. DCO was calculated off-line, by multiplying stroke volume with heart rate: DCO = stroke volume × heart rate. Results:The aortic valve orifice was easily imaged in all patients. Excellent-quality continuous-wave Doppler flow profiles were obtained in nearly all (62 of 63). A total of 109 DCO determinations were performed. Mean DCO was 4.35 ± 1.18 1·min-1 (range 2.02-7.42 1·min-1), and mean TCO was 4.41 ± 1.17 1·min-1 (range 2.24-8.94 1·min-1). Very high correlation and agreement were found between the two methods: DCO = 0.94 × TCO + 0.19, r=0.94, SEE (standard error of the estimate) = 0.41 1·min-1; 95% confidence interval=0.06 ± 0.83 1·min-1. Relative changes from pre- to postbypass CO (Δ) also showed a strong correlation (ΔDCO=0.93 × ΔTCO + 5.4%, r=0.82, SEE=17.8%). For CO changes greater than 10%, Doppler was in accordance with thermodilution in 43 of 45 measurements. DCO repeatability coefficient was 0.51 1·min-1. Conclusions:Compared to thermodilution, continuous-wave Doppler measurements of blood flow velocity across the aortic valve in the transesophageal echocardiographic transgastric view allow accurate CO determination.

Lack of Effectiveness of the Pulmonary Artery Catheter in Cardiac Surgery

BACKGROUND: The pulmonary artery catheter (PAC) continues to be used for monitoring of hemodynamics in patients undergoing coronary artery bypass graft (CABG) surgery despite concerns raised in other settings regarding both effectiveness and safety. Given the relative paucity of data regarding its use in CABG patients, and given entrenched practice patterns, we assessed the impact of PAC use on fatal and nonfatal CABG outcomes as practiced at a diverse set of medical centers. METHODS: Using a formal prospective observational study design, 5065 CABG patients from 70 centers were enrolled between November 1996 and June 2000 using a systemic sampling protocol. Propensity score matched-pair analysis was used to adjust for differences in likelihood of PAC insertion. The predefined composite endpoint was the occurrence of any of the following: death (any cause), cardiac dysfunction (myocardial infarction or congestive heart failure), cerebral dysfunction (stroke or encephalopathy), renal dysfunction (dysfunction or failure), or pulmonary dysfunction (acute respiratory distress syndrome). Secondary variables included treatment indices (inotrope use, fluid administration), duration of postoperative intubation, and intensive care unit length of stay. After categorization based on PAC and transesophageal echocardiography use (both, neither, PAC only, transesophageal echocardiography only), we performed the primary analysis contrasting PAC only and neither (total, 3321 patients), from which propensity paring yielded 1273 matched pairs. RESULTS: The primary endpoint occurred in 271 PAC patients versus 196 without PAC (21.3% vs.15.4%; adjusted odds ratio [AOR], 1.68; 95% confidence interval [CI], 1.24 to 2.26; P < 0.001). The PAC group had an increased risk of all-cause mortality, 3.5% vs 1.7% (AOR, 2.08; 95% CI, 1.11 to 3.88; P = 0.02) and an increased risk of cardiac (AOR, 1.58; 95% CI, 1.14 to 2.20; P = 0.007), cerebral (AOR, 2.02; 95% CI, 1.08 to 3.77; P = 0.03) and renal (AOR, 2.47; 95% CI, 1.68 to 3.62; P < 0.001) morbid outcomes. PAC patients received inotropic drugs more frequently (57.8% vs 50.0%; P < 0.001), had a larger positive IV fluid balance after surgery (3220 mL vs 3022 mL; P = 0.003), and experienced longer time to tracheal extubation (15.40 hours [11.28/20.80] versus 13.18 hours [9.58/19.33], median plus Q1/Q3 interquartile range; P < 0.0001). Use of PAC was also associated with prolonged intensive care unit stay (14.5% vs 10.1%; AOR, 1.55; 95% CI, 1.06 to 2.27; P = 0.02). CONCLUSIONS: Use of a PAC during CABG surgery was associated with increased mortality and a higher risk of severe end-organ complications in this propensity-matched observational study. A randomized controlled trial with defined hemodynamic goals would be ideal to either confirm or refute our findings.

A randomized double-blinded multicenter comparison of remifentanil versus fentanyl when combined with isoflurane/propofol for early extubation in coronary artery bypass graft surgery

We compared a fentanyl/isoflurane/propofol regimen with a remifentanil/isoflurane/propofol regimen for fast-track cardiac anesthesia in a prospective, randomized, double-blinded study on patients undergoing elective coronary artery bypass graft surgery. Anesthesia was induced with a 1-min infusion of 0.5 mg/kg propofol followed by 10-mg boluses of propofol every 30 s until loss of consciousness. After 0.2 mg/kg cisatracurium, a blinded continuous infusion of remifentanil at 1 &mgr;g · kg−1 · min−1 or the equivalent volume rate of normal saline was then started. In addition, a blinded bolus syringe of 1 &mgr;g/kg remifentanil or 10 &mgr;g/kg fentanyl, respectively, was given over 3 min. Blinded remifentanil, 1 &mgr;g · kg−1 · min−1 (or the equivalent volume rate of normal saline), together with 0.5% isoflurane, were used to maintain anesthesia. Significantly more patients (P < 0.01) in the fentanyl regimen experienced hypertension during skin incision and maximum sternal spread compared with patients in the remifentanil regimen. There were no differences between the groups in time until extubation, discharge from the surgical intensive care unit, ST segment and other electrocardiogram changes, catecholamine levels, or cardiac enzymes. The remifentanil-based anesthetic (consisting of a bolus followed by a continuous infusion) resulted in significantly less response to surgical stimulation and less need for anesthetic interventions compared with the fentanyl regimen (consisting of an initial bolus, and followed by subsequent boluses only to treat hemodynamic responses) with both drug regimens allowing early extubation.

The efficacy and resource utilization of remifentanil and fentanyl in fast-track coronary artery bypass graft surgery : A prospective randomized, double-blinded controlled, multi-center trial

We compared (a) the perioperative complications; (b) times to eligibility for, and actual time of the following: extubation, less intense monitoring, intensive care unit (ICU), and hospital discharge; and (c) resource utilization of nursing ratio for patients receiving either a typical fentanyl/isoflurane/propofol regimen or a remifentanil/isoflurane/propofol regimen for fast-track cardiac anesthesia in 304 adults by using a prospective randomized, double-blinded, double-dummy trial. There were no differences in demographic data, or perioperative mortality and morbidity between the two study groups. The mini-mental status examination at postoperative Days 1 to 3 were similar between the two groups. The eligible and actual times for extubation, less intense monitoring, ICU discharge, and hospital discharge were not significantly different. Further analyses revealed no differences in times for extubation and resource utilization after stratification by preoperative risk scores, age, and country. The nurse/patient ratio was similar between the remifentanil/isoflurane/propofol and fentanyl/isoflu-rane/propofol groups during the initial ICU phase and less intense monitoring phase. Increasing preoperative risk scores and older age (>70 yr) were associated with longer times until extubation (eligible), ICU discharge (eligible and actual), and hospital discharge (eligible and actual). Times until extubation (eligible and actual) and less intense monitoring (eligible) were significantly shorter in Canadian patients than United States’ patients. However, there was no difference in hospital length of stay in Canadian and United States’ patients. We conclude that both anesthesia techniques permit early and similar times until tracheal extubation, less intense monitoring, ICU and hospital discharge, and reduced resource utilization after coronary artery bypass graft surgery.

Role of Mitral Valve Plication in the Surgical Management of Hypertrophic Cardiomyopathy

BACKGROUND We have previously reported our 3-step repair for obstructive hypertrophic cardiomyopathy (HCM) consisting of resection of the septum, horizontal plication of the anterior mitral leaflet (AML), and release of abnormal papillary muscle attachments. This article reviews our complete experience with surgical management of HCM to better understand the role and relevance of mitral plication. METHODS From 1997 to 2011, 132 patients with HCM underwent surgical treatment at our institution. Eighty-two patients (62%) received AML plication based on selection criteria and were classified as group A; patients in group B did not receive plication. All patients underwent preoperative and postoperative echocardiography. Long-term clinical follow-up was obtained by review of scheduled echocardiograms and direct patient interview. RESULTS The average age of all patients was 55.5 years. Operative mortality was 0%. The mean left ventricular outflow tract (LVOT) gradient decreased from 118±41 mm Hg to 6±13 mm Hg (p<0.0001). Mean mitral regurgitation improved from 2.4±1.0 to 0.5±0.7 (p<0.0001). Postoperatively, 96.2% of patients had no residual systolic anterior motion (SAM). Significant improvements in heart failure classification and quality of life scores were noted for all patients. Comparison of groups A and B showed no statistically significant differences in outcomes, complications, or survival. Survival at 1, 5, and 10 years was 98%, 98%, and 92%, respectively. CONCLUSIONS The heterogeneity of the pathologic process in HCM supports detailed analysis of the septum, mitral leaflets, and subvalvular apparatus. Surgical management of HCM that includes horizontal plication of a lax and elongated AML is safe and results in durable clinical and echocardiographic improvement.

The association between Doppler transmitral flow variables measured by transesophageal echocardiography and pulmonary capillary wedge pressure.

The association between Doppler transmitral flow variables, measured by transesophageal echocardiography (TEE), and pulmonary capillary wedge pressure (PCWP) was studied in 88 patients undergoing coronary artery surgery.The Doppler flow variables and PCWP were measured after sternotomy by blinded investigators. In the first part of the study, patients were divided into two groups according to left ventricular (LV) ejection fraction (EF): Group A, EF >35% (n = 38) and Group B, EF <or=to35% (n = 34). In Group B, significant correlations were found between deceleration time of early filling (DCT-E) and PCWP (r2 = 0.899) and deceleration slope of early filling and PCWP (r2 = 0.692), (P < 0.001 for both). When the relationship between DCT-E and PCWP was tested prospectively in a third group of patients [Group C; EF <or=to 35% (n = 16)], a close agreement between the calculated and measured PCWP (bias = -0.55 +/- 3.87 mm Hg) was noted. The sensitivity, specificity, and positive predictive value of DCT-E >or=to150 ms for PCWP <10 mm Hg were 93.3%, 100%, and 100%, respectively. In summary, patients with decreased left ventricular systolic function undergoing coronary artery surgery demonstrated high, statistically significant, correlations between PCWP and the deceleration time or deceleration slope of early diastolic filling as measured by transesophageal Doppler echocardiography. (Anesth Analg 1997;84:491-6)

A comparison of left ventricular performance indices measured by transesophageal echocardiography with automated border detection.

Background Automated border detection (ABD) allows semiautomated measurement of left ventricular (LV) areas. They can be combined with left ventricular pressure signals to generate pressure‐area loops and pressure‐dimension indices of contractility. This study compared conventional indices of ventricular performance (fractional area change [FAC] and circumferential fiber shortening [Vcfc]) with pressure‐dimension indices of contractility. A secondary aim was to compare the effects of volatile anesthetics on the indices. Methods Using transesophageal echocardiography with automated border detection, FAC and Vcfc were obtained in 23 patients after cardiopulmonary bypass. Left ventricular pressures were obtained with a left ventricular catheter. Preload reduction by inferior vena caval occlusion was used to obtain end‐systolic elastance (Ees), preload recruitable stroke force (PRSF), and dP/dtmax [middle dot] EDA‐1 (EDA = end‐diastolic area). In 11 patients, the measurements were repeated at 1 end‐tidal minimum alveolar concentration of halothane or isoflurane. The results are expressed as mean +/‐ SD. Results After cardiopulmonary bypass, FAC was 31.1 +/‐ 7.9%, Vcfc was 0.6 +/‐ 0.2 circ [middle dot] s‐1, Ees was 25.8 +/‐ 11.6 mmHg [middle dot] cm‐2, PRSF was 60.8 +/‐ 26.6 mmHg, and dP/dtmax [middle dot] ‐EDA‐1 was 245 +/‐ 123.4 mmHg [middle dot] s‐1 [middle dot] cm‐2. At 1 minimum alveolar concentration of a volatile anesthetic agent, FAC, Vcfc, and dP/dtmax [middle dot] EDA‐1 remained unchanged. Significant decreases in Ees (19%) and PRSF (28%) were observed. Conclusions The association between pressure‐dimension indices and Vcf (c) or FAC was weak or nonexistent. A reduction in myocardial contractility induced by the administration of volatile anesthetic agents was detected by Ees and PRSF, but not by FAC, Vcfc, or dP/dtmax [middle dot] EDA (‐1). After myocardial revascularization, Ees and PRSF appear more sensitive than FAC or Vcfc for measuring changes in contractility.

A study of the human aortic valve orifice by transesophageal echocardiography

The transverse short-axis plane of the aortic valve was imaged by transesophageal echocardiography at a relatively high frame rate in 25 anesthetized patients undergoing heart surgery. The effective, time-averaged aortic valve area (a-AVA) was compared with areas obtained with triangular and circular valve orifice models (t-AVA and c-AVA, respectively). The aortic valve orifice was circular during 33.6% +/- 17.5% of systole. The relations between the triangular or circular aortic valve areas and a-AVA were as follows: t-AVA = 1.04 x a-AVA - 0.14 (r = 0.90; standard error of the estimate = 0.24 cm2) and c-AVA = 1.37 x a-AVA + 0.00 (r = 0.90; SEE = 0.30 cm2). Bias analysis showed no significant difference between a-AVA and t-AVA (bias = -0.04 +/- 0.23 cm2; difference not significant) but a significant overestimation of the average valve area by c-AVA (bias = +0.88 +/- 0.30 cm2; p < 0.001). Thus the aortic valve orifice was not circular for the entire duration of systole and valve area calculations based on a triangular model approximated a-AVA more closely than did those based on a circular model. These findings suggest that, for echocardiographic measurements that incorporate the aortic valve orifice area (e.g., stroke volume determinations), the use of a triangular valve area model, rather than a circular model, may produce more accurate results in anesthetized patients with heart disease.

Left atrial function is unchanged by implantable defibrillator shocks on hearts in sinus rhythm.

Sixteen patients in sinus rhythm at baseline undergoing implantable cardioverter-defibrillator implantation were monitored with transesophageal echocardiography both before and after direct current cardioversion with currents of 15 to 20 J, for any direct current induced atrial dysfunction. We found no change in the indexes of atrial function or appearance of spontaneous echo contrast in the immediate postshock period by intraoperative transesophageal echocardiography.

Clinical transesophageal echocardiography, a problem-oriented approach

of the topic for example four lines on ‘Safe anaesthetic in liver disease’. Other parts are much too basic to fulfil the author’s objectives of being a useful reference for senior trainees and consultants but would be relevant for new trainees. Just when you might get frustrated you come across one of the many helpful algorithms such as the ‘Management of paediatric murmurs’ algorithm or the practical and comprehensive antithrombotic prophylaxis and postoperative pain management guidelines. It is imperative in a small didactic book like this that the advice is practical, up-to-date and accurate. The information regarding hypertension, the management of diabetes mellitus and steroid replacement therapy does not meet such a high standard. The sections covering Physiology, Pharmacology/ statistics and Audit lend themselves much better to the authors approach. There are numerous aspects of the basic sciences that I cannot precisely bring to mind for teaching trainees and this small book would be helpful in that regard. Like wise, it may provide a useful adjunct to revision for both parts of the FRCA. The emergency section is comprehensive, includes all the advance life support algorithms and is well laid out with a largely consistent recognition and management approach. The authors describe this book as a ‘compilation of lists and diagrams ... for reference when a fact, statistic or formula eludes the memory’ and not a ‘definitive pocket textbook of anaesthesia’. With so many reproduced good algorithms and useful nuggets of information the book is at its best when it sticks to this objective. It is difficult to see who will buy this book though as the practical areas are too basic for the target readership whilst complex topics are too sparsely covered for the novice. It may be useful for the departmental library but I won’t be recommending it to the trainees.