Zaki-Udin Hassan

Transesophageal Echocardiography for the Noncardiac Surgical Patient

Transesophageal echocardiography (TEE) has been established as a very valuable asset for patient monitoring during cardiac surgery. The value of perioperative TEE for patients undergoing noncardiac surgery is less clear. This article reviews the technical aspects of TEE and comments on the potential benefit of using TEE as a monitoring modality apart from cardiac surgery. Based on patients comorbidities and/or injury pattern, TEE is a fast and minimally invasive approach to obtain important hemodynamic information, especially useful in a hemodynamically unstable patient. However, certain requirements for the use of the technique are necessary, most important the development of sufficient echocardiographic skills by the anesthesiologists. Indications, skill requirements, and possible complications of the technique are reviewed.

Using a mannequin-based simulator for anesthesia resident training in cardiac anesthesia.

Simulators are used for training medical personnel. This report details the use of a human patient simulator for initial clinical experience of anesthesia housestaff with cardiopulmonary bypass.

Anesthetic Implications of Obesity in the Surgical Patient

The obese patient presents many challenges to both anesthesiologist and surgeon. A good understanding of the pathophysiologic effects of obesity and its anesthetic implications in the surgical setting is critical. The anesthesiologist must recognize increased risks and comorbidities inherent to the obese patient and manage accordingly, optimizing multisystem function in the perioperative period that leads to successful outcomes. Addressed from an organ systems approach, the purpose of this review is to provide surgical specialists with an overview of the anesthetic considerations of obesity. Minimally invasive surgery for the obese patient affords improved analgesia, postoperative pulmonary function, and shorter recovery times at the expense of a more challenging intraoperative anesthetic course. The physiologic effects of laparoscopy are discussed in detail. Although laparoscopys physiologic effects on various organ systems are well recognized, techniques provide means for compensation and reversing such effects, thereby preserving good patient outcomes.

How do we integrate thromboelastography with perioperative transfusion management

F or the foreseeable future, conventional coagulation testing will remain important for anticipation, intervention, and management of hemorrhage and thrombosis in surgical patients. Conventional tests used at our institution include platelet (PLT) count, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen levels, sometimes other factor levels, and D-dimer. Activated clotting time (ACT; International Technidyne Corp., Edison, NJ) is a point-of-care (POC) test run in our operating room. However, today’s complex and prolonged operations increasingly require effective, targeted use of blood products and hemostasis-altering drugs, which in turn demands more complete and timely coagulation information than conventional testing typically provides. Inherently long turnaround times can render laboratory results irrelevant before they can be reported, creating demand for POC testing including ACT and PLT function screening assays such as the PLT function analyzer (PFA-100; Siemens USA, Washington, DC). POC testing has its own limitations, including cost, quality control (QC), equipment maintenance, and correlation with laboratory-based testing. Available, more sophisticated testing can do a better job for complex surgical patients in the operating room. Another limitation of most coagulation tests is their artificial, analytical nature, which isolates components of the hemostasis system under contrived laboratory conditions. The in vivo coagulation mechanism resembles an intricate ballet performed by flowing red blood cells (RBCs), PLTs, subendothelial proteins, and various circulating proenzymes and cofactors on a dynamic threedimensional stage of phospholipid bilayers and meshed fibrin strands, resulting in a clot that stanches hemorrhage, remains localized to the site of injury, and gradually dissolves as healing proceeds. No in vitro coagulation test will ever do full justice to the in vivo system. While also artificial, whole blood thromboelastography (TEG) nevertheless more closely mimics physiologic hemostasis, providing specific information about coagulation status in real time, and it is currently used extensively at our institution to guide specific interventions with blood product replacement and drug therapy. The basic technology was developed by Hartert in the late 1940s, but was not widely used until much more recently. Two versions of this technique are currently available: TEG (Haemonetics Corp., Braintree, MA) and ROTEM (Tem International GmbH, Munich, Germany). A third method, Sonoclot (Sienco, Inc., Arvada, CO), employs a slightly different clot detection principle. This article will focus on TEG because we currently use it at our institution (Fig. 1). The test is conceptually simple. In our laboratory, a small quantity of fresh citrated whole blood is mixed with kaolin and excess calcium, much as in the aPTT, except that in TEG, the RBCs and PLTs remain to fulfill their physiologic roles. The multiple variables of TEG include not only the time to initial clot detection (the sole endpoint of the aPTT) but also the subsequent rate of clotting, the strength of the clot over time, and the rate and degree of clot lysis. Since both the primary (PLT-related) and the secondary (factor-related) components of hemostasis participate in the reaction, the features of the curve can identify and guide management of thrombocytopenia, factor deficiencies, hypofibrinogenemia, fibrinolysis, or inappropriate dosing of hemostasis-altering agents. At our institution, we primarily use citrated whole blood samples. Versions of TEG using citrated or very fresh uncitrated blood with or without kaolin are available as ABBREVIATIONS: ACT = activated clotting time; aPTT = activated partial thromboplastin time; CPB = cardiopulmonary bypass; LMWH = low-molecular-weight heparin; MA = maximum amplitude; PT = prothrombin time; R time = reaction time; TEG = thromboelastography.

Initial results of a structured rotation in hematology and transfusion medicine for anesthesiology residents.

STUDY OBJECTIVE To develop and evaluate a new curriculum in transfusion medicine for anesthesiology residents. STUDY DESIGN Quasi-experimental study. SETTING Single center, pilot curriculum in the anesthesiology residency program at a university-affiliated medical center. PARTICIPANTS Group TM consisted of residents who participated in the one month-long transfusion medicine rotation in postgraduate year 2 (PGY2; n = 9). The comparison group (non-TM) consisted of residents who had no exposure to the transfusion medicine rotation (n = 21). MEASUREMENTS We compared results of the 2009 American Board of Anesthesiology In-Training Exam (ABA-ITE) 2009 by residents of our program with the national performance of residents in the first clinical anesthesia year (AMG CA1 = PGY-2) and second clinical anesthesia year (AMG CA2 = PGY-3) on transfusion medicine/hematology knowledge. Performance on a pre-test and post-test of those who took part in the transfusion medicine curriculum, and overall performance on the ABA-ITE, of departmental residents who had and had not participated in the Transfusion Medicine curriculum within the target knowledge area of hematology/transfusion medicine and compared against national peer performance data, was assessed. An anonymous electronic survey (5-Point Likert scale) was used to assess the perceived educational value of the curriculum. MAIN RESULTS Transfusion medicine-related knowledge of anesthesia residents markedly improved from the pre- to post-rotation examination and on the ABA-ITE. In the ABA-ITE 2009, the TM group performed better than their national peers (AMG CA1 and CA2) in the hematology content area. The post-rotation anonymous resident survey indicated high resident satisfaction. CONCLUSIONS A structured transfusion medicine curriculum improved anesthesiology resident knowledge in transfusion medicine and was associated with high learner satisfaction.

Integrating echocardiography into human patient simulator training of anesthesiology residents using a severe pulmonary embolism scenario.

Introduction: Echocardiographic images were integrated into patient simulation (PS)-based resident training with a goal of highlighting the applicability and limitations of pure pressure-based measurements in the management of different disease states. Methods: Relevant echocardiographic images were selected, categorized, and sequenced to best represent specific hemodynamic changes and incorporated into a Powerpoint slideshow. Appropriate PS scenarios were then created to represent the hemodynamic changes seen with the selected pathophysiologic states. Instructors then displayed the visual images along with PS scenarios during lecture and testing sessions at the PS bedside during standard didactic sessions with small groups of anesthesiology residents and informal resident testing sessions. Conclusions: The use of echo images to demonstrate, in real time, the hemodynamic consequences of changes in myocardial contractility, cardiac chamber volume, and valvular function is possible during PS in anesthesiology residency training. Echo imaging as a teaching tool during anesthesiology residency may yield a greater understanding of the pathophysiology of certain disease states, ultimately leading to faster diagnosis and more appropriate intervention by anesthesiologists.

Surgical Resident Training Using Real-Time Simulation of Cardiopulmonary Bypass Physiology with Echocardiography

BACKGROUND With increasing complexity of medical care and continuing limitations on medical education, the use of simulation is becoming ever more important. Several simulators have been developed to teach procedural-based surgical tasks. The care of the cardiac surgical patient requires an in-depth understanding of physiology, particularly as pertains to cardiopulmonary bypass. We describe the use of the Human Patient Simulator (HPS) to teach perioperative fundamentals to surgical residents. METHODS General surgery residents from the University of Kentucky participated in an interactive simulation pilot program. The METI (Medical Education Technology, Inc, Sarasota, Florida) HPS was used with custom programming to demonstrate simulated intraoperative and postoperative physiology related to cardiopulmonary bypass. Didactics, in addition to intraoperative echocardiographic images, were provided. Fund of knowledge was assessed by a computerized pre- and posttest that was administered to the trainees, and self-assessment data were collected using a Likert scale. RESULTS Nineteen general surgery residents participated. An overall improvement in performance on the test was demonstrated from 63% correct to 85% correct. In general, residents found the simulation useful, appreciated the opportunity to treat crisis situations without risk of harm to a patient, and felt they could apply the knowledge gained from this program in their future practice. CONCLUSIONS Simulation serves as a useful adjunct to medical education. We have demonstrated the use of the HPS to provide a real-time simulation of the physiology of cardiopulmonary bypass and postoperative care. We plan to use this system as part of our standard curriculum of training rotating residents and junior fellows and anticipate this system could be used as part of future cardiothoracic simulations.

The patient simulator for training of anesthesia residents in the management of one lung ventilation.

Simulators are used extensively for the training of medical personnel. All anesthesia providers should be prepared and trained in the management of one lung ventilation for pulmonary surgery, yet familiarization with one lung ventilation may not be possible on a routine basis in the operating room. Therefore, this reports details the first use of the patient simulator (PS) to enhance the training of anesthesia residents in the management of one lung ventilation. A detailed report of our computer program for simulating one lung ventilation is included.

Transesophageal echocardiography monitoring in the delivery of a preeclamptic parturient with severe left ventricular noncompaction

A multidisciplinary approach to the preterm delivery of a preeclamptic parturient with severe left ventricular (LV) noncompaction and pulmonary hypertension using transesophageal echocardiography (TEE) as a monitor of hemodynamic status in lieu of a pulmonary artery catheter during general anesthesia for Cesarean section is presented. This case adds to the available literature on LV noncompaction with pulmonary hypertension in preeclamptic parturients, and addresses the anesthetic concerns and approaches to management using echocardiography in these highly complex patients.

Neurophysiological monitoring simulation using flash animation for anesthesia resident training.

Introduction: Surgery of the spine is associated with the possible complication of permanent nerve injury. Neurophysiological monitoring is widely used during spine surgery to decrease the incidence and severity of neurologic injury. A profound understanding of physiological and pharmacological factors influencing evoked potentials is expected from the anesthesia provider. Methods: Because demonstration and teaching of all somatosensory evoked potential (SSEP) changes is difficult in the clinical environment, we developed human patient simulator scenarios to facilitate the anesthesia resident training in neurophysiological monitoring. A SSEP simulation for resident training was created using flash animation in a patient simulation program and is the focus of this report. Feedback from participants (anesthesia residents) was obtained by a postscenario survey. Results: This report provides a detailed description of the scenario and computer program. The survey findings indicated that the simulation session is an effective teaching method of SSEP monitoring. Conclusion: Flash animation integration into a patient simulation program for SSEP monitoring appears to be an effective method for anesthesia resident education in neurophysiological monitoring.