Consequences of electroencephalographic-suppressive doses of propofol in conjunction with deep hypothermic circulatory arrest.

BACKGROUND: Some patients who undergo cerebral aneurysm surgery require cardiopulmonary bypass and deep hypothermic circulatory arrest. During bypass, these patients often are given large doses of a supplemental anesthetic agent in the hope that additional cerebral protection will be provided. Pharmacologic brain protection, however, has been associated with undesirable side effects. These side effects were evaluated in patients who received large doses of propofol. METHODS: Thirteen neurosurgical patients underwent cardiopulmonary bypass and deep hypothermic circulatory arrest to facilitate clip application to a giant or otherwise high-risk cerebral aneurysm. Electroencephalographic burst suppression was established before bypass with an infusion of propofol, and the infusion was continued until the end of surgery. Hemodynamic and echocardiographic measurements were made before and during the prebypass propofol infusion and again after bypass. Emergence time also was determined. RESULTS: Prebypass propofol at 243 +/- 57 micrograms.kg-1.min-1 decreased vascular resistance from 34 +/- 8 to 27 +/- 8 units without changing heart rate, arterial or filling pressures, cardiac index, stroke volume, or ejection fraction. Propofol blood concentration was 8 +/- 2 micrograms/ml. Myocardial wall motion appeared hyperdynamic at the end of cardiopulmonary bypass, and all patients were weaned therefrom without inotropic support. After bypass, vascular resistance decreased further, and cardiovascular performance was improved compared to baseline values. Nine of the 13 patients emerged from anesthesia and were able to follow commands at 3.1 +/- 1.4 h. Three others had strokes and a fourth had cerebral swelling. CONCLUSIONS: Propofol infused at a rate sufficient to suppress the electroencephalogram does not depress the heart or excessively prolong emergence from anesthesia after cardiopulmonary bypass and deep hypothermic circulatory arrest.

Cardiac performance preserved despite thiopental loading.

BACKGROUND: Some cerebral artery aneurysms require cardiopulmonary bypass and deep hypothermic circulatory arrest to be clipped safely. During bypass these neurosurgical patients often are given large doses of thiopental in the hope that additional cerebral protection will be provided. However, thiopental loading during bypass has been associated with subsequent cardiac dysfunction in patients with heart disease. This study was undertaken to determine how patients without concomitant heart disease would respond to thiopental loading. METHODS: Twenty-four neurosurgical patients with giant cerebral aneurysms and little or no cardiac disease were anesthetized with fentanyl, nitrous oxide, and isoflurane. Thiopental was titrated to achieve electroencephalographic burst-suppression before bypass, and the infusion was continued until after separation. Prebypass hemodynamic and echocardiographic measurements were obtained during a stable baseline and 15 min after thiopental loading began. They were repeated after bypass. RESULTS: Prebypass thiopental loading increased heart rate from 61 +/- 11 to 72 +/- 13 beats/min and decreased stroke volume from 43 +/- 10 to 38 +/- 8 ml.beat-1.m-2, but arterial and filling pressures, vascular resistance, cardiac index, and ejection fraction remained the same. Before bypass, thiopental plasma concentration measured 28 +/- 8 micrograms/ml. Loading continued for 2-3 h until after bypass was terminated, and the overall infusion rate was 18 +/- 5 mg.kg-1.h-1. All patients were easily separated from bypass without inotropic support. Following bypass, vascular resistance was decreased; heart rate, filling pressures, and cardiac index were increased; stroke volume had returned to its baseline; and ejection fraction was unchanged. CONCLUSIONS: It was concluded that if preoperative ventricular function is good, thiopental loading to electroencephalographic burst-suppression causes negligible cardiac impairment and does not impede separation from cardiopulmonary bypass.

Protein-losing enteropathy detected by 99mTc-labeled human serum albumin abdominal scintigraphy.

99mTc-labeled human serum albumin (HSA) abdominal imaging is a new way of demonstrating gastrointestinal protein loss. We present two children with hypoalbuminemia of obscure etiology in whom albumin loss was localized in the gastrointestinal tract with 99mTc-HSA scintigraphy and the loss correlated with abnormal fecal alpha 1-antitrypsin excretion. In the absence of gastrointestinal blood loss or contamination of the 99mTc-HSA with free pertechnetate, significant activity accumulating in the gastrointestinal tract and moving with its contents is thought to represent 99mTc-HSA leakage into bowel lumen. Abdominal imaging with 99mTc-HSA has a low radiation burden to the patient and is readily available, relatively inexpensive, and easily performed. It can be used as a screening test for the detection of protein-losing enteropathy. It also offers the potential of being able to localize the site of protein loss visually within the gastrointestinal tract.

Computed tomography of the brain in the Smith-Lemli-Opitz syndrome.

Computed tomographic (CT) scans of the brain in a child with Smith-Lemli-Opitz syndrome revealed enlargement of the ventricular system, hypoplasia of the cerebellum, and abnormal thickening of the gray matter, consistent with pachygyria. These findings have been previously noted in autopsies performed on patients with this disorder. We conclude that CT scanning is a valuable tool in the evaluation of children suspected of having the Smith-Lemli-Opitz syndrome.