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H K Cheung

Publications and source records attributed to H K Cheung.

At least 19 recordsLinked to original sources
PubMed2005

The components of executive functioning in a cohort of patients with chronic schizophrenia: a multiple single-case study design.

We examined the fractionation of executive functioning performance in ninety patients with schizophrenia, who were tested for initiation, sustained attention, switching/flexibility, attention allocation and impulsivity/disinhibition. The participants were also given tests of general intelligence and memory. We analysed the executive functioning performance of individual patients against normative data from our laboratory, and summary scores for all of the executive functioning components were computed. For each component, participants were classified as having impairment with a test performance of 1.5 standard deviations or more from the norm of the corresponding test. Of all of the participants, 27.8% (n=25) demonstrated poor performance in all of the components, and 5.6 % (n=5) exhibited intact or fair performance in all of the components. Furthermore, 18.9% (n=17) showed intact or fair performance in one component, 16.7% (n=15) in two components, 21.1% (n=19) in three components and 10% (n=9) in four components. The groups did not differ in education, gender or duration of illness, but the group that showed impaired performance in all of the components demonstrated the most severe psychotic symptoms after controlling for background intelligence, age and medication. The differential breakdown for the executive functioning performance across the participants suggests that the fractionation of central executive functioning occurs in schizophrenia.

Adult↗
PubMed2005

The significance of hepatic vein outflow volume in hepatic outflow insufficiency of living right liver graft evaluated by Doppler ultrasound.

The color Doppler ultrasound has been used to evaluate hepatic vein (HV) outflow insufficiency based on flow velocity and waveforms. In our experience, some cases with flat waveforms are clinically asymptomatic. The parameters of HV flow velocity and waveforms are not always correlated with clinical problems. So, we proposed that total HV flow volume (HVFV) may be a more reliable index. From August 2001 to July 2003, 31 cases among 48 adult-to-adult living related transplants of a right liver graft had one HV anastomosis. HV velocity, waveforms, and HVFV were compared both before and after transplantation. We set the minimal HVFV ratio at 80% based on the original HVFV before graft retrieval. There was no significant difference in HVFV before liver graft retrieval between the 2 groups, but there was a significant change after transplantation. There were no cases of HV insufficiency among group A patients (>80%), whose HVFV ranged from 397 to 1181 mL/min with ratios from 75% to 180% (mean 115%). In group B, there were 4 complicated cases with prolonged severe ascites (<80%) with HVFV ratios from 56% to 76% (mean 66%). Fisher exact test showed a great significance (P < .001). Thus the preliminary criteria of 80% minimal HVFV ratio allows detection of HV insufficiency for further interventional management.

Adult↗
PubMed2004

Problem-solving ability in chronic schizophrenia. A comparison study of patients with traumatic brain injury.

We tested the hypothesis that patients with schizophrenia are more prone to impairment in planning and problem-solving as compared with normal controls and patients with traumatic brain injury (TBI) by administering the Tower of Hanoi (TOH) task. A total of one hundred and fifty-three participants (51 in each group) were recruited. The performance of the patient groups was markedly worse than normal controls in terms of profile score, number of rule-breaking behaviour, and mean execution time. Two-way 3 (group) x 6 (complexity) ANOVAs indicated that significant main effects of group and complexity were observed in the number of moves, planning time to initiate the first move and subsequent execution time. The general performance of TOH in the schizophrenia group was very similar to that of the TBI group. Subsequent comparison of sub-groups of frontal and posterior lobe damage indicated the pattern of performance in schizophrenia patients lie between them. Taken together, these findings suggest that neither focal frontal nor temporal lobe damage is a sufficient explanation for the problem-solving deficits in patients with schizophrenia.

Adult↗
PubMed2004

Executive dysfunctions in schizophrenia. Relationships to clinical manifestation.

Studies suggest that executive functions in patients with schizophrenia are markedly impaired as compared with normal controls. Most previous studies employed tests of executive functions adopted from frontal lobe neuropsychological paradigms based on lesion studies. This study employed several more recently developed theory-driven tests of executive functions addressing the construct of the supervisory attentional system. We explore the pattern of executive function impairment using factor analysis and subsequently investigate the relationships between these executive function factors and the clinical features in a sample of chronic schizophrenic patients. A total of 51 patients with chronic schizophrenia were recruited. The Sustained Attention Response to Task (SART), Six Elements Test (SET) and Hayling Sentence Completion Test (HSC) were used to assess executive functions. Three factors were identified within the executive function tests: 1) The "semantic inhibition factor" comprised items in the HSC, 2) the "action/attention inhibition" factor comprised the SART commission error and the SET rule-breaking score and 3) the "output generation factor" comprised the SET raw score and the correct SART response. Significant relationships were found between these derived factors and clinical features after partialling out the confounding effect of age, education and illness duration. The three theory-based tests of executive function were shown to have good construct validity among the group of chronic schizophrenic patients.

Adult↗
PubMed2004

A study of sensitivity of the sustained attention to response task in patients with schizophrenia.

The sustained attention to response task (SART), a measure of sustained attention created by Robertson, Manly, Andrade, Baddeley, and Yiend (1997), was administered to 51 patients with schizophrenia and 51 normal controls to provide information on the sensitivity of the measure in this clinical group. Patients with schizophrenia performed significantly worse than the normal controls in correct response, reaction time for correct response, and efficiency estimate of taking account of both the accuracy and speed of movement. Moreover, the patient group was more often correctly classified as defective on the basis of efficiency estimate than the normal controls. These data provide further evidence of the sensitivity of the SART to patients with schizophrenia.

Adult↗
PubMed2001

Single imaging modality evaluation of living donors in liver transplantation: magnetic resonance imaging.

BACKGROUND: Liver graft size, anatomy of the bile duct and the vascular inflow and outflow are essential for living related liver transplantation (LRLT). Preoperative delineation of those variations that would change the operative procedure to achieve a successful result especially in an emergency condition. PURPOSE: Our aim was to develop a rapid and noninvasive imaging diagnostic method for the detection of anatomical variants that is mandatory for a safe operation when selecting potential liver transplant living donors. We used a different magnetic resonance (MR) imaging technique, which enabled to us to exploit the anatomical landmark of the liver, signal enhancement of blood flow in the abdomen, and the intrahepatic biliary routes inside the liver. Then, with the help of Advantage Window workstation reconstruction, the reconstructed single vascular or biliary systems were displaced in a three-dimensional fashion and the whole examination finished within 30 min. METHODS: Modification of the standard MR technique was performed on a superconductive 1.5T whole body image scanner, MR arteriogaphy, venography, and cholangiography with three-dimensional reconstruction in evaluating the anatomy of the hepatic arteries, hepatic veins, portal venous system, bile ducts, and liver size in potential liver transplant living donors. These anatomical structures were compared with traditional imaging methods. RESULTS: In all 38 cases, as well as delineation of the portal vein detail to the segmental level was satisfactorily obtained in this MR study. The images were well displayed in a three-dimensional fashion, which had good correlation with images from traditional imaging modalities and operative findings. In 86.8% cases, the MR arteriography was well matched with the celiac angiography. Of those 17 operative cases, estimation of liver volume was well correlated with the liver graft within 3.9-12.5% variation. In the major hepatic vein, we obtained 100% accuracy and 88.2% in the minor branches. Of 12 donors received intraoperative cholangiography during liver donation, good correlation of biliary anatomy was achieved. One donor was excluded from graft donation due to the complicated arterial supply to the left liver. According to the anatomical variation, surgical procedures in graft harvesting and anastomosis were readjusted and no major complications were found in those donors and all recipients survived after liver transplantation. CONCLUSION: MR volumetry, venography, angiography, and cholangiography with three-dimensional reconstruction is sufficient for all major imaging evaluation. It may replace the traditional conventional catheter angiography, computed tomography, sonography and endoscopic retrograde cholangiography as a single investigation in the evaluation of the potential liver transplant donors. Angiography is only valuable in suboptimal cases and intraoperative cholangiography is only performed in biliary ductile variants.

Adult↗
PubMed2001

Interventional radiologic procedures in liver transplantation.

Postoperative biliary and vascular complications contribute significantly to morbidity and mortality in liver transplantation. Interventional radiologists are an integral part of the multidisciplinary team necessary for optimizing the management of these complications. During a 15-year period, 39 cadaveric and 25 living related liver transplantations were performed at the Chang Gung Memorial hospital, Taiwan. Of 64 liver transplant recipients, 9 (3 adult and 6 pediatric) underwent 13 interventional radiological procedures for the treatment of biliary sludge-casts (n = 2), bile duct occlusion or stenosis (n = 2), hepatic veins thrombosis (n = 1), hepatic veins stenosis (n = 1), portal vein stenosis with splenorenal shunting (n = 1), biloma (n = 1), and infected fluid collection or ascites (n = 4). Antegrade or retrograde interventional approach was used to successfully treat all biliary complications, and all percutaneous drainage procedures were effective in the control of intra-abdominal fluid collections. Portal vein stenosis was treated by balloon dilatation, and the associated splenorenal shunt was closed by metallic coil embolization via transhepatic catheterization of the portal vein. Hepatic vein stenosis was effectively treated by balloon dilatation and expandable metallic stent deployment via transfemoral and jugular venous approaches, respectively. Hepatic vein thrombosis was only partially lysed by transvenous streptokinase administration, and surgical thrombectomy was needed to achieve complete recanalization. The total success rate of the interventional procedures was 92 % with no procedure-related complications. The overall survival rate in this series is 89 %, and all patients who underwent living related liver transplantation maintain to date a 100 % survival rate. We can conclude that interventional radiological procedures are very useful for managing biliary and vascular complications after liver transplantation. These techniques provide a cure in most situations, thus obviating the need for further surgical intervention or re-transplantation.

Adolescent↗
PubMed2001

Biliary complications in living related liver transplantation.

BACKGROUND: Biliary tract reconstruction has long been considered the Achilles' heel of liver transplantation as biliary complications can increase morbidity and mortality especially in partial liver graft transplantation. METHODS: Thirty-four living related liver transplants were performed at Chang Gung Memorial Hospital in Kaohsiung for 33 children and 1 adolescent during a 5.5-year period. All potential donors underwent a detailed preoperative imaging study of the vascular and biliary anatomy, including three-dimensional helical computed tomographic cholangiography (n = 20), magnetic resonance cholangiography (n = 14), and intra-operative cholangiography (n = 31) before graft retrieval. All hepatic artery anastomoses were performed in the standard microsurgery fashion and their patency was confirmed intra-operatively using Doppler ultrasound. RESULTS: The biliary complication rate was 8.8% (3/34), including multiple intrahepatic biliary stenosis of unknown origin (n = 1), bile leakage from the Roux-en-Y loop (n = 1), and a missed biliary radicle (n = 1) which were treated via interventional radiological and surgical procedures. The overall graft and patient survival rates were 100%. CONCLUSION: The biliary complication rate in this series was low compared to those of other experienced centers. Complete study of the variations of intrahepatic duct ramification pre-and-intra-operatively provided adequate information on the appropriate transection plane. Furthermore, intra-operative Doppler ultrasound verification of vessel patency helps prevent vascular complications, which has been identified as a cause of biliary complications.

Adolescent↗
PubMed2000

Outflow tract reconstruction in living donor liver transplantation.

BACKGROUND: Hepatic venous reconstruction is critical in living donor liver transplantation because outflow obstruction may lead to graft dysfunction or loss. We describe our experience and analyze outcomes with a technique of creating a single outflow tract using venoplasties of the graft and recipient hepatic veins. PATIENTS AND METHODS: A retrospective study was done on 38 consecutive living donor liver transplants performed from June 1994 to March 2000. The grafts included 36 left-side grafts and 2 right-side grafts. Nine grafts had multiple hepatic veins and required a venoplasty of two or three hepatic veins to create a single outflow orifice. Triple recipient hepatic venoplasty was performed in 32 patients, double venoplasty in 5 and none in 1. RESULTS: There were four cases of outflow obstruction, three occurring in patients with a double recipient venoplasty. Two of the problems were remedied intraoperatively by adjusting the position of the graft although two were structural in nature and required the insertion of expandable metallic vascular stents. All donors and recipients with their original grafts are alive at a mean follow-up period of 27 months. CONCLUSION: A triple recipient venoplasty with a matching venoplasty of multiple graft hepatic veins to create a single wide outflow orifice is recommended in living donor liver transplantation using left side grafts.

Adolescent↗
PubMed2000

Minimal blood loss living donor hepatectomy.

BACKGROUND: Donor hepatectomy with maximal safety while preserving graft viability is of principal concern in living donor liver transplantation. There are compelling reasons for avoiding blood transfusion, even with autologous blood, to avoid the potential risks it imposes on healthy donors. This study aims to describe the surgical technique and clinical outcomes of living donor hepatectomy with minimal blood loss requiring no blood transfusion. METHODS: Donor hepatectomy was performed in 30 living donors according to a detailed preoperative imaging study of the vascular and biliary anatomy. Liver parenchymal transection was carried out with strict adherence to a meticulous surgical technique without vascular inflow occlusion to either side of the liver. Pre-, intra-, and postoperative data were gathered, and factors related to blood loss were analyzed retrospectively. RESULTS: The intraoperative blood loss ranged from 20 to 300 ml with a mean of 72.0+/-58.9 ml (median, 55 ml), and neither homologous nor autologous blood transfusion was required in any of the donors intra- and postoperatively. All 30 donors were discharged with minimal complications, and remain well at a mean follow-up of 24 months after donation. Excellent graft viability was verified by the fact that all 30 recipients are alive and well with a few manageable complications. The actual graft and patient survival are both 100% at the time of writing. CONCLUSIONS: Regardless of the extent of donor hepatectomy, blood loss can and should be kept to a minimum, and living donor hepatectomy without blood transfusion is a realistic objective.

Adolescent↗
PubMed2000

Aspiration in chest compression alone without mechanical ventilation in the head down position in dogs.

BACKGROUND: Previous work by the authors has shown that chest compressions alone without mechanical ventilation during cardiopulmonary resuscitation in the natural supine position was associated with pulmonary aspiration in dogs. The purpose of this investigation was to test the hypothesis that a head down position may prevent aspiration during chest compressions alone and whether oxygenation can be improved by simply insufflation of oral oxygen 10 min after cardiac arrest. METHODS: Cardiac arrest was induced in ten mongrel dogs which were anesthetized and paralysed. Eight underwent chest compressions alone in different head down positions using an automatic compressor at 9 kg compression force and 3 cm compression depth. The study was composed of two parts. Part 1 evaluated the effect of insufflation of 10 l/min O2, into the mouth of the dogs, 10 min after initiation of resuscitation, using chest compressions alone. Part 2 was designed to test our hypothesis that the head down position may protect the lungs from aspiration during chest compression alone. The mouths of the dogs were filled with mixed barium and the dogs underwent serial episodes of chest compressions, for 10 min each, in the 20 degree head down, 10 degree head down and the natural supine positions. Chest X-rays with antero-posterior and lateral views were taken to evaluate pulmonary aspiration. Two additional dogs underwent direct chest compression alone in the natural supine position and the time of chest compression was shortened to 5 min. RESULTS: All dogs in the natural position showed evidence of pulmonary aspiration of barium, five or six of the dogs showed tracheal aspiration in the 10 degree head down position, while no any barium was visualized in the tracheo-broncheal trees of the dogs in the 20 degree head down position. Supplemental oxygen in the mouth improved the mean PaO2 from 67 +/- 26 to 160 +/- 97 mmHg during chest compressions alone. CONCLUSION: Chest compression alone without mechanical ventilation in the supine position caused pulmonary aspiration in the unprotected airway in dogs. This complication could be prevented by adopting a 20 degree head down position. The 10 degree head down position seemed to reduce the severity of the pulmonary aspiration, but not enough to eliminate the danger altogether. Supplemental oxygen in the mouth can improve oxygenation in chest compressions alone.

Administration, Oral↗
PubMed2000

Repeated hypotensive episodes due to hepatic outflow obstruction during liver transplantation in adult patients.

We report two cases of unusual repeated hypotension, decreased cardiac output, decreased mixed venous oxygen saturation, decreased central venous pressure, pulmonary artery pressure, and pulmonary wedge pressure after the completion of all vascular anastamoses of liver transplantation. These unstable hemodynamics appear to reflect a clinically relevant picture of hypovolemia. However, the real cause was partial hepatic outflow obstruction. The obstruction was suspected because hypotension was alleviated by elevating the full-sized liver graft ventrally and to the left. Doppler ultrasound examination confirmed that the flow velocity of the hepatic vein outflow was insufficient when the liver fell to its resting position in the right hepatic fossa. An additional side-to-side cavo-caval anastomosis resolved the problem in one patient, whereas the other required not only the additional anastomosis, but also application of a tissue expander filled with 770 mL normal saline beneath the liver to eliminate the obstruction. We emphasize that obstruction of the hepatic outflow causes only temporal hypovolemia because of a decrease of venous return and that treatment of this complication should be surgical intervention to relieve the obstruction. Blind resuscitation with fluids will not solve the problem and, in fact, may result in fluid overload with subsequent complications.

Adult↗