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Biomedical subjects

G Lau

Publications and source records attributed to G Lau.

50 records · Page 3Linked to original sources

Amniotic fluid embolism: a review of 10 fatal cases.

A study of 10 fatal cases of amniotic fluid embolism, confirmed by autopsy and post-mortem histological examination, that occurred in Singapore between 1983-1992, showed that the majority (9 cases) were multiparous, with between 2-4 previous normal pregnancies each. Seven had uneventful antenatal histories. In all cases, the clinical onset was sudden and unexpected, having occurred during the first stage of labour in 8 subjects and being associated with convulsions in 5. There were seven cases of coagulopathy, with 6 of disseminated intravascular coagulation. Overall, foetal survival was poor. Three cases were associated with induction of labour, while another 3 occurred after augmentation. Emergency caesarean sections were performed in 5 cases. Autopsy demonstrated moderate to severe pulmonary oedema in 9 cases, accompanied by pulmonary haemorrhage in 6. Mild coronary atheroma was present in 6 cases, with 3 showing subendocardial haemorrhage. Significant utero-cervical ruptures or lacerations were found in 3 cases. Microscopy demonstrated the presence of squamous epithelial emboli within the pulmonary vasculature in all cases. Other histological features included fibrin microthrombi (3 cases), alveolar and pulmonary interstitial inflammation, focal myocardial and hepatocellular necrosis, and myocardial interstitial inflammation. Although the precise pathogenesis of amniotic fluid embolism has remained somewhat enigmatic, recent evidence points towards a combination of a severe haemodynamic disturbance followed by secondary coagulopathy in about 40% of patients who survive the initial event. Leucotrienes, prostaglandins and other vasoactive substances contained in amniotic fluid are postulated to play a fundamental role in its pathogenesis. Amniotic fluid is also thought to possess thromboplastin-like properties.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Peri-operative deaths in Singapore: a forensic perspective in a study of 132 cases.

A study of 132, largely non-traumatic, peri-operative deaths out of 6605 Coroner's autopsies, conducted over a three-year period from 1989 to 1991, showed a preponderance of males (M:F ratio = 1.36), with almost half (46.3%) being middle-aged subjects between 40 to 59 years, while infants (< one year old) made up about a tenth of the cases. A total of 51 cases (38.6%) were related to cardiothoracic surgery, which also accounted for the majority of deaths that had occurred intra-operatively (11/21 or 8.3% in all) and within the first postoperative day (16/36 or 12.1% in all). The vast majority of cases (81.8%) were pathologically natural deaths, with 15.2% attributable to complications or mishaps of surgery and invasive diagnostic or therapeutic procedures. There were three anaesthetic deaths which accounted for 2.3% of the cases. Out of 124 completed Coroner's inquiries as at the end of June 1993, verdicts of death from natural causes were recorded in 110 (83.3%) cases. General surgery accounted for the highest proportion of unnatural deaths (6.1%), which was twice that for cardiothoracic surgery (3.0%). While there was close agreement between a finding of a pathologically natural death and a similar Coroner's verdict (107/110 or 97.3%), only a total of ten out of 23 pathologically unnatural deaths received verdicts of misadventure at the time of writing. Although a verdict of misadventure usually pertained to an iatrogenic death, this was not invariably the case. Thus far, no findings of medical negligence was made in any of the Coroner's inquiries into these cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Connection of electronic medical devices in ICU according to the standard 'MIB'.

In the daily routine of an SICU, particularly in cardiac surgery, the nurses are to an increasing extent confronted with problems of connecting and using medical instruments as well as with documentation of the data of these instruments. An increasing number of user errors is to be expected. Use of advanced computer technology can help avoid such errors. In this paper the system 'ALODIN' is presented which is developed in our institutions according to the IEEE standard 'Medical Information Bus' (MIB). ALODIN-I will be part of a CCCS (computerized critical care system) which is installed in the clinic for cardiovascular surgery at Medical School Hannover.

Computer Peripherals↗

Isolated colonic hemangioma in a child.

Hemangiomas of the large bowel are very rare and usually occur in the rectosigmoid. A large cavernous hemangioma of the colon was demonstrated in a 9-month-old child who presented with recurrent lower gastrointestinal tract bleeding. Barium examination demonstrated an annular lesion of the hepatic flexure. Computed tomography demonstrated the extent of the lesion, and contrast enhancement suggested the vascular nature of the tumour before a laparotomy was performed to remove the tumour.

Colonic Neoplasms↗

Use of a computerized closed-loop sodium nitroprusside titration system for antihypertensive treatment after open heart surgery.

This study evaluates the clinical applicability of administering sodium nitroprusside by a closed-loop titration system compared with a manually adjusted system. The mean arterial pressure (MAP) was registered every 10 and 30 sec during the first 150 min after open heart surgery in 20 patients (group 1: computer regulation) and in ten patients (group 2: manual regulation). The results (16,343 and 2,912 data points in groups 1 and 2, respectively), were then analyzed in four time frames and five pressure ranges to indicate clinical efficacy. Sixty percent of the measured MAP in both groups was within the desired +/- 10% during the first 10 min. Thereafter until the end of observation, the MAP was maintained within +/- 10% of the desired set-point 90% of the time in group 1 vs. 60% of the time in group 2. One percent and 11% of data points were +/- 20% from the set-point in groups 1 and 2, respectively (p less than .05, chi-square test). The computer-assisted therapy provided better control of MAP, was safe to use, and helped to reduce nursing demands.

Adult↗

Omental pedicle grafting in the treatment of postcardiotomy sternotomy infection.

Postcardiotomy sternal infection occurred in 20 (2%) of 1007 patients undergoing cardiac surgery between September 1985 and December 1987, a 10-fold increase over the preceding 33 months (4 [0.24%] of 1627 patients). Cultures were sterile in 5 patients and yielded staphylococci in 12 and a variety of bowel organisms in 3. The cause for the increased occurrence of sternal wound infection is unclear after multivariate analysis, although infections have precipitously dropped subsequent to changing to cefuroxime sodium antibiotic prophylaxis. Treatment has evolved to appropriate antibiotics and early débridement of involved sternum and cartilage. Rewiring the sternum is not attempted. If gross purulence is not present, primary closure is accomplished using muscle flaps (2 patients) or omental pedicle grafts (17 patients). In the presence of gross purulence, the wound is packed open for 5 days and then closed in the above fashion. Two patients required skin grafts for primary closure. The omental pedicle flap is preferred due to simplicity and improved coverage of the sternal defect inferiorly. Nineteen patients healed primarily. A superficial wound infection was drained in 1 patient. Midline incisional hernias developed in 3 muscular patients. Omentum is now harvested through a left subcostal incision. Hospital stay was under 2 weeks in 13 patients. One death occurred due to multisystem failure prior to completion of wound closure. In our experience, early sternal débridement and omental pedicle grafting with primary closure is appropriate therapy for postcardiotomy sternotomy infections. The presence of gross purulence may require 5 days of open packing prior to omental grafting. No significant complications occurred, and mortality was low. A left subcostal incision for omental harvesting is utilized to avoid the occurrence of delayed incisional hernias.

Cardiac Surgical Procedures↗

Potential exposure of cooks to airborne mutagens and carcinogens.

Recent case-control and proportionate mortality studies in Canada, the United States, Britain, and Denmark have shown that cooks and other food-service workers may have elevated risks of cancers of the nasopharynx, buccal cavity, esophagus, lung, and bladder. The purpose of this pilot study was to determine if there might be airborne products of cooking which may be risk factors for these cancers in cooks. Eight air samples were taken in four restaurants and subsequently analyzed for mutagenicity using the Ames assay, and for carcinogens using gas chromatography/mass spectrometry. All four samples taken in the restaurant cooking areas were mutagenic to TA98 without metabolic activation, and two were mutagenic to TA100 also without metabolic activation. Of the four dining area samples, one was mutagenic to TA100 and one to TA98, both without metabolic activation. Compounds tentatively identified by mass spectrometry did not include known carcinogens. The ventilation systems in all four restaurants allow the exposure of cooks to both the air from dining room smoking areas and the volatile products of cooking.

Air Pollutants, Occupational↗

Closure of bronchopleural fistulas by an omental pedicle flap.

Bronchopleural cutaneous fistulas are a serious problem that are difficult to treat with any assurance of success. Thoracoplasty, muscle pedicle grafts, and attempts at reclosure have been used with limited success. We have used the omental flap technique in the management of five patients with bronchopleural cutaneous fistulas. In our patients and in four cases in the literature, the success rate has been 100 percent. The omental pedicle flap is a simple way to close bronchopleural fistulas. It avoids extensive chest wall dissection and destruction in patients who often have marked respiratory embarrassment and other underlying disease. The results have been excellent.

Bronchial Fistula↗

[Anorectal continence following manual and mechanical anastomosis suture. Results of a controlled study of rectal surgery].

In a controlled clinical trial-manual vs. stapler anastomosis in rectal surgery-it was found that both suture techniques per se made no difference in the function of anal continence. The anal pressures at rest and sphincter contraction remained unchanged. A linear reduction of functional reservoir of the "neorectum" could be shown, which depended on the level and healing of the anastomosis. An anastomosis level at 6 cm from anocutaneous line is important for functional reasons. Anastomoses above this level do not cause any consequences for anal continence. Anastomoses below this level result in a reduced functional reservoir for at least 6 months. Within this period a decrease in anal continence is possible, especially in cases of disturbed healing of the anastomosis.

Adult↗

Effects of public description on the detection and tolerance of laboratory pain.

Experimental procedures designed to modify an hypothesized pain detection threshold were arranged to test the notion that to describe a painful experience publicly results in subsequent increased detection of similar pain. First, subjects were pre-tested on their ability to detect and tolerate cold pressor pain. While waiting for a second test, half of the subjects were engaged in conversation by a confederate to whom the subject described his/her impressions of the pre-test. The other half waited in silence for the second test. Results showed that, relative to those who did not describe pain, subjects who publicly described the pain experience had low pain thresholds on the post-test, tolerated the pain less long and reported engaging in a greater number of thoughts indicating that the pain started sooner and was more intense on the post-test. Possible mechanisms to explain this effect are discussed, clinical implications are presented and directions for future research on the same process are outlined.

Adaptation, Psychological↗

Prevention of complications after liver trauma.

Treatment of 681 cases of liver trauma during the past ten years at the San Francisco General Hospital was reviewed. The mortality was 14.7 per cent and the morbidity rate 18.9 per cent. The complications relating specifically to liver injury were bleeding subphrenic or subhepatic abscesses, intrahepatic abscess, biliary fistula, and liver failure. These complications and the recommended management of the liver injury are discussed.

Adolescent↗

A preoperative protocol for the prevention of infection in children with tunnelled right atrial catheters.

The use of central venous lines has come to be widely accepted by children with cancer and their families. However, attendant infection is a cause of considerable morbidity. Coagulase-negative staphylococci, the predominant aerobic species on the skin, are now the commonest cause of catheter-related bacteremia. We introduced a protocol to reduce the colonization of the skin at the catheter insertion site. Antiseptic skin scrubs, with 4% chlorhexidine gluconate, were performed on the neck and anterior chest the night before and again on the morning of the surgical procedure. A single dose of cephalothin (or vancomycin for penicillin-allergic patients) was administered IV immediately before the operation. Compared to the 12 month period prior to initiation of this protocol, the rate of infections (occurring within 30 days of catheter placement) in the 3.5 year period of intervention dropped from 8 to 4.9 per 1,000 catheter days. The proportion of infections that were staphylococcal was reduced from 93 to 63% and the proportion of non-ports removed within 30 days of placement fell from 45 to 0%. Despite these changes, the major contribution to improved infection control appeared to be the use of an increased proportion of ports (a rise from <10 to almost 60%).

Administration, Topical↗

Closing time.

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England↗