Friday, May 10, 2013

E-CHALLENGES & CLINICAL DECISIONS

E-CHALLENGES & CLINICAL DECISIONS

Feroze Mahmood, MD Madhav Swaminathan, MD
Section Editors


Major Surgery, Hemodynamic Instability, and a Left Atrial Appendage Clot: What to Do?

Remco Bergman, MD, Omair Shakil, MD, Bilal Mahmood, BA, and Robina Matyal, MD


A 77-YEAR-OLD PATIENT was scheduled for emergency spinal surgery for multiple cervical vertebral fractures. He had sustained bilateral fractures of the C5 and C6 pedicles after falling from his bed. Of note, the injury was associated with neurologic deficits (motor and sensory) in the upper and lower extremities and the patient’s cervical spine was deemed unstable. His medical history was significant for coronary artery disease, congestive heart failure, and transient ischemic attacks and he had an automatic internal cardiac defibrillator placed recently for recurrent ventricular tachycardia.

After obtaining intravenous access by 2 peripheral catheters and 1 arterial catheter, the patient was brought to the operating room. The induction of general anesthesia was uneventful and the airway was secured with modified rapid-sequence induction using a glidescope while maintaining inline traction. Immediately after the start of the surgery, the patient went into atrial fibrillation (AF), with a heart rate of 120-130 beats/min, accompanied by a decrease in blood pressure from 110/80 to 80/50 mmHg. There were no accompanying ST-segment changes on the electrocardiogram. The position of his endotracheal tube was confirmed, the depth of anesthesia was ensured, and he was administered a rapid fluid bolus of lactated Ringer’s solution, 500 mL. Intermittent boluses of intravenous phenylephrine (500 [H9262]g) and esmolol (total 50 mg) also were administered to support his systolic blood pressure and control his heart rate, respectively. With these measures, the patient’s heart rate decreased to 90 beats/min and his blood pressure improved to 90/50 mmHg. Given his medical history of coronary artery disease and persistent hemodynamic instability, transesophageal echocardiography (TEE) was performed to assess his volume status and cardiac function. The TEE demonstrated mild symmetric left ventricular hypertrophy with cavity dilation, global moderate-to-severe systolic dysfunction, an ejection fraction of 30%, and severe diastolic dysfunction (decreased compliance) with an E/e= of 15. There also was moderate aortic stenosis (AS) with an aortic valve area of 1.0 cm2. Although the degree of myocardial dysfunction was known from the patient’s history, the moderate AS was a new finding. In addition, the left atrium was dilated moderately, with a sluggish flow and significant spontaneous echocardio-graphic contrast in the left atrial appendage (LAA). Interestingly, an echodensity measuring 2 cm [H11003] 1.5 cm also was visualized in the LAA; the appearance of which was consistent with a thrombus (Fig 1).


Fig 1. Midesophageal 2-chamber view showing the left atrial appendage with an echodensity most consistent with a thrombus.


ECHOCARDIOGRAPHIC FINDINGS

1. The presence of a significant compliance abnormality of the left ventricle, given the patient’s history of congestive heart failure, necessitated a judicious approach to fluid administration.

2. The occurrence of AF with moderate AS, leading to a loss of an atrial contribution to left ventricular filling, required fluid administration.

3. The moderate AS and LAA thrombus were unexpected findings.


From the Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA

Address reprint requests to Omair Shakil, MD, Research Fellow, Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, One Deaconess Road, CC-470, Boston, MA 02215. E-mail: oshakil@bidmc.harvard.edu

© 2013 Elsevier Inc. All rights reserved. 1053-0770/2703-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2012.09.007

Journal of Cardiothoracic and Vascular Anesthesia, Vol 27, No 3 (June), 2013: pp 625-626

625
626 BERGMAN ET AL

CLINICAL CHALLENGES

1. To achieve optimal fluid management, despite the contradictory demands of the patient’s clinical situation; ie, AF and AS requiring fluid administration versus the conservative approach demanded by the decreased left ventricular compliance.

2. Optimal management of the AF and LAA thrombus; ie anticoagulation (risk of persistent hemodynamic instability) versus cardioversion (risk of thrombus dislodgement).


CLINICAL DECISIONS

1. The patient’s blood pressure was supported with pre-load augmentation and [H9251]-adrenergic drugs (phenylephrine).
2. Heart rate control was achieved with [H9252]-adrenergic blocking drugs (esmolol).

3. A mutual decision was reached with the surgical team to withhold cardioversion to decrease the risk of possible LAA thrombus dislodgement.

4. A cardiology consultation was scheduled in the immediate postoperative period to manage the anticoagulation and AF.


DISPOSITION

Afterwards, the patient was extubated uneventfully and transferred to the coronary care unit. On the second postoperative day, intravenous heparin infusion was started, which was bridged to oral anticoagulation with coumadin. The patient was discharged a few days later in stable condition.


EDITORIAL

Anesthesiologists and Transesophageal Echocardiography: Echocardiographers or Echocardiologists?

DURING HEMODYNAMIC INSTABILITY, clinicians choose to use monitors which they are most accustomed to.1 The time-limited nature of decision-making in the perioperative arena necessitates an approach that quickly can establish a diagnosis and dictate treatment. The use of TEE under such circumstances has been established as an essential monitor.2 The therapeutic impact of intraoperative TEE traditionally has been defined as a change in the surgical/anesthetic management or the addition of postoperative follow-up.3 Life-threatening hypoxia and intractable hypotension are considered category I indications for intraoperative TEE3 and there is unequivocal evidence of the impact of TEE for these indications. However, the use of intraoperative TEE to confirm a clinical suspicion with no change in therapy generally is not considered a major therapeutic intervention. Although arguably equally valuable, such an impact is difficult to quantify and therefore not considered, possibly leading to an underestimation of the true therapeutic effect.

The case presented in this issue of the Journal highlights many of these very important and debatable issues.4 The presented patient undergoing emergency cervical spine surgery suddenly developed significant hemodynamic instability shortly after the start of surgery. At this point, the anesthesia team did not have adequate access to the patient to place invasive monitoring lines, and the traumatic nature of the case made it a rather urgent situation. The team quickly had to establish or exclude a diagnosis for the sudden hemodynamic instability. Under the circumstances, a rapid TEE examination was the most obvious and logical choice. However, although the TEE examination provided the necessary answers, it raised certain questions. A thrombus was visualized unexpectedly in the left atrial appendage during TEE. Although atrial fibrillation and hemodynamic instability are indications for an emergency cardioversion, the presence of a left atrial appendage

thrombus was a complicating factor. The risk of possible dislodgment of the thrombus with cardioversion had to be weighed against the risk of further hemodynamic deterioration. Although a discussion of the pros and cons of cardioversion under these circumstances is beyond the scope of this editorial, this intraoperative situation represented a decision-making dilemma. The multiple complicating factors (history of trauma, nature of the injury/surgery, atrial fibrillation, and the unexpected finding of a left atrial appendage thrombus) necessitated a patient-specific approach in a multidisciplinary fashion.

Although the patient did not have “life-threatening” hemodynamic instability, the circumstances were such that a diagnosis had to be established or excluded rapidly. Although TEE provided the desired information, ironically it created a clinical challenge, with no absolutely correct answers. Not only did TEE assist in resuscitation and the exclusion of diagnoses, it also had an enormous therapeutic impact in the conventional sense, in that it changed the anesthetic management and eventual disposition of the patient.5

With the increasing use of intraoperative TEE, anesthesiologists are finding themselves in unchartered territories and increasingly are involved in the decision-making that was once considered outside the scope of their traditional practice and expertise. There seems to have been a gradual transformation of anesthesiologists’ role from perioperative “echocardiographer” to “echocardiologist.” This changes the anesthesiologists’ role from a service provider to an active decision-maker with the ability to affect outcome.5

Remco Bergman, MD Feroze Mahmood, MD
Department of Anesthesia, Critical Care, and Pain Medicine
Beth Israel Deaconess Medical Center
Harvard Medical School
Boston, MA


REFERENCES
1. Jacka MJ, Cohen MM, To T, et al: The use of and preferences for the transesophageal echocardiogram and pulmonary artery catheter among cardiovascular anesthesiologists. Anesth Analg 94:1065-1071, 2002

2. Mahmood F, Christie A, Matyal R: Transesophageal echocardiography and noncardiac surgery. Semin Cardiothorac Vasc Anesth 12:265-289, 2008

3. American Society of Anesthesiologists and Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography: Practice guidelines for perioperative transesophageal echocardiography. An updated report by the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists Task Force on Transesophageal Echocardiography. Anesthesiology, 112:1084-1096, 2010
4. Bergman R, Shakil O, Mahmood B, et al: Major surgery, hemo-dynamic instability, and left atrial appendage clot: What to do? J Cardiothorac Vasc Anesth 2012 (in press)

5. Suriani RJ, Neustein S, Shore-Lesserson L, et al: Intraoperative transesophageal echocardiography during noncardiac surgery. J Cardiothorac Vasc Anesth 12:274-280, 1998


© 2013 Elsevier Inc. All rights reserved. 1053-0770/2703-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2012.09.008