Selective percutaneous transhepatic embolization of the portal vein in preparation for extensive liver resection: the ipsilateral approach.

The ipsilateral approach was used at preoperative portal vein embolization in 38 patients with hepatobiliary malignancy. The right anterior portal branch was punctured. Two different 5.5-F triple-lumen balloon catheters were used, and fibrin glue and iodized oil were injected. Portal vein embolization was successful in all cases (right lobe, 24 patients; left lobe and right anterior segment, six; right lobe and left medial segment, three; right posterior segment, two; right anterior segment, one; left lobe, one; and right and caudate lobes, one).

Resection of metastatic liver cancer in a patient with an anomalous intrahepatic portal system: a case report.

Resection of metastatic liver cancer in a patient with an anomalous intrahepatic portal system is presented. A 67-year-old man was referred to our hospital with a liver tumor. Percutaneous transhepatic portography demonstrated that the right anterior branch of the portal vein rose from the left portal vein with agenesis of the umbilical portion. Cholangiography disclosed obstruction of the right posterior segmental bile duct by the tumor. Barium enema demonstrated a Borrmann type II cancer in the sigmoid colon. Right hepatic lobectomy and high anterior resection of the colon were performed, and postoperative histologic examination confirmed that the liver tumor was metastatic adenocarcinoma of the colon. The ligamentum teres arose from the right anterior portal vein and separated the left medial segment from the right anterior portal segment of the liver. These anomalies led to the performance of right lobectomy instead of trisegmentectomy and the patient died 10 months later of hepatic recurrence. This case emphasizes the importance of delineating the hepatic vascular anatomy before liver resection and illustrates one of the pitfalls related to portal venous anomalies.

Biofeedback training for reduced respiratory rate in chronic obstructive pulmonary disease: a preliminary study.

The overall objective of this preliminary investigation was to determine whether breathing patterns of patients with chronic obstructive pulmonary disease could be altered by training patients to voluntarily change their breathing, using techniques of biofeedback training. The specific aims were (1) to develop a method of monitoring respiratory rate and tidal volume with a device that was both accurate and usable without discomfort or inconvenience to the patient; (2) to use the method with patients having chronic obstructive pulmonary disease to determine whether respiratory rate could be slowed by voluntary controls; and (3) to determine whether patients who could slow their breathing rate would increase their tidal volume and demonstrate other respiratory changes.

Biofeedback of alveolar carbon dioxide tension and levels of arousal.

This is a preliminary study designed to investigate the potential usefulness of alveolar (lung) CO2 feedback training in promoting sleep onset in primary insomniacs. The present study was undertaken to determine if normal subjects could, without obvious manipulation of breathing, bring alveolar (lung) CO2 tension under voluntary control using biofeedback techniques and, if so, whether this control would be accompanied by shifts in level of wakefulness. Subjects participated in five baseline and five training sessions in which EEG, alveolar CO2 tension, and thoracic/abdominal respiratory movement were monitored. The feedback consisted of a pitch-modulated tone plus visual scores. We found that CO2 tension in awake portions of "up" trials was significantly higher than for awake portions of "down" trials (p less than .01), indicating that learning had occurred. In the initial trials, when subjects raised CO2 tension they became drowsy and often fell asleep, and when they lowered CO2 tension they aroused themselves. However, when subjects were awakened immediately upon falling asleep, there developed a decoupling of EEG and CO2 changes. The presence of such a decoupling phenomenon makes it unclear whether CO2 feedback will be useful in promoting sleep onset in primary insomniacs.

Anxiety change through electroencephalographic alpha feedback seen only in high anxiety subjects.

Subjects who were either high or low in trait anxiety used alpha feedback to increase and to decrease their electroencephalographic alpha activity. The alpha changes were tightly linked to anxiety changes, but only in high anxiety subjects (for whom anxiety was reduced in proportion to alpha increases, and was increased in proportion to alpha suppression). Low trait-anxiety subjects were superior at both enhancement and suppression training, but their alpha changes were not related to anxiety changes. In both groups, anxiety changes were generally unrelated to either resting levels or changes in frontalis electromyograms and respiration rate. These results suggest that long-term alpha feedback training (at least 5 hours) may be useful in anxiety therapy.

Methodological issues in alpha biofeedback training.

Current controversies concerning outcomes of EEG alpha feedback training are at least in part due to methodological differences among different studies. The aim of this paper is to provide future and present researchers in this field with an analysis of methods used in most of the studies published from 1968 to 1976, and to comment on those methodological issues we think most important. These include alpha assessment, training schedules, and uni- versus bidirectional training. This analysis is accomplished in part by a series of tables listing 45 studies and the detailed methodologies used. It is believed that the probabilities of successful feedback enhancement of alpha can be substantially improved by incorporating the following suggestions: (a) employing at least four training sessions, (b) the use of continuous rather than dichotomous feedback, supplemented by periodic quantitative scores of progress, and (c) using training trials of at least 10 minutes' duration.

Conflicting results in EEG alpha feedback studies: why amplitude integration should replace percent time.

Success or failure of EEG feedback training for alpha enhancement can depend on how alpha activity is quantified and fed back. Alpha-enhancement failures usually employ a percent time (%) technique; successes typically use amplitude integration (variation of). To dramatize the differences between percent and integration techniques, we derived both measures simultaneously from left occipital (O1) and left central (C3) sites for 16 male subjects who were given 5.6 hours of integrated alpha feedback from the midline occipital (Ozeta) site. At both the O1 and C3 sites the integrated and percent measures were not equivalent and not linearly related. Statistically significant differences in the (integrated, percent) correlation coefficients (z-transpormed) were observed under the different recording conditions: alpha enhancement, alpha suppression, and baselines. Theoretical discussion of integration and percent techniques is given and the adoption of amplitude integration measures and feedback stimuli is strongly advocated.