Chronotropic incompetence on dobutamine stress echocardiography in candidates for a liver transplant.

OBJECTIVES: We evaluated dobutamine stress echocardiography as an initial screening test for a cardiac evaluation before a liver transplant. MATERIALS AND METHODS: We retrospectively examined 111 liver transplant candidates who had undergone previous cardiac evaluation; 30 of whom had undergone a liver transplant. RESULTS: Eighty patients (72.1%) completed a dobutamine stress echocardiography (41 chronotropically competent, 39 incompetent), while 31 patients (27.9%) required us to terminate early. Overall, 68 patients (61%) were on ß-blockers (21 required early dobutamine stress echocardiography termination, 30 chronotropically incompetent, and 17 competent). Patient results were normal. Thirty patients underwent a liver transplant. Among candidates requiring termination of early dobutamine stress echocardiography, posttransplant cardiac events included 1 fatal acute myocardial infarction, 1 nonfatal acute myocardial infarction, and 1 idiopathic cardiomyopathy. Among chronotropically incompetent patients, 2 patients had transient bradycardia, and among those who were chronotropically competent, 1 had refractory atrial fibrillation, and 1 had transient bradycardia. CONCLUSIONS: Nearly 50% of patients with end-stage liver disease may not reach the target heart rate. Early termination of dobutamine stress echocardiography because of cardiac symptoms or significant echocardiographic changes have more effect in predicting postoperative cardiac events, but further evaluation is required even if their target heart rate is close to that desired. Lower target heart rate may be acceptable in chronotropically incompetent individuals provided they are asymptomatic, have no echocardiographic changes, or cardiovascular risk factors, especially if they are on ß-blockers.

Anesthetic considerations in candidates for lung volume reduction surgery.

The administration of anesthesia to patients undergoing lung volume reduction surgery (LVRS) requires a complete understanding of the pathophysiology of severe chronic obstructive pulmonary disease, the planned surgical procedure, and the anticipated postoperative course for this group of patients. Risk factors and associated morbidity and mortality are discussed within the context of patients with obstructive pulmonary disease in the National Emphysema Treatment Trial having surgical procedures. Preoperative evaluation and the anesthetic techniques used for patients undergoing LVRS are reviewed, as are monitoring requirements. Intraoperative events, including induction of anesthesia, lung isolation, management of fluid requirements, and options for ventilatory support are discussed. Possible intraanesthetic complications are also reviewed, as is the optimal management of such problems, should they occur. To minimize the potential for a surgical air leak in the postoperative period, positive-pressure ventilation must cease at the conclusion of the procedure. An awake, comfortable, extubated patient, capable of spontaneous ventilation, is only possible if there is careful attention to pain control. The thoracic epidural is the most common pain control method used with patients undergoing LVRS procedures; however, other alternative methods are reviewed and discussed.

A surprising twist: an unusual failure of a keyed filling device specific for a volatile inhaled anesthetic.

We describe two cases in which keyed filling devices for sevoflurane were inadvertently screwed onto isoflurane bottles. The mishaps were possible because the collars on sevoflurane and isoflurane bottles are mirror images of each other. The particular keyed filling device was designed with a flexible outer sleeve and could be screwed onto the wrong bottle while slightly gouging its soft plastic collar. The keyed filling adapters for sevoflurane and isoflurane could each be manipulated to fit the other's bottle. A manufacturer (Southmedic, Inc., Barrie, Canada) has modified their keyed filling adapters to prevent this unusual circumstance from recurring.