Field assessment of nanoscale bimetallic particles for groundwater treatment.

A field demonstration was performed in which nanoscale bimetallic (Fe/Pd) particles were gravity-fed into groundwater contaminated bytrichloroethene and other chlorinated aliphatic hydrocarbons at a manufacturing site. With diameters on the order of 100-200 nm, the nanoparticles are uniquely suited to rapidly degrade redox-amenable contaminants and for optimal subsurface delivery and dispersion. Approximately 1.7 kg of the nanoparticles was fed into the test area over a 2-day period, resulting in minimal clogging of the injection well. The test area was located within a well-characterized region of the contaminant plume and included an injection well and three piezometer couplets spaced 1.5 m apart. Despite the low nanoparticle dosage, trichloroethene reduction efficiencies of up to 96% were observed over a 4-week monitoring period with the highest values observed at the injection well and adjacent piezometers. Data from the field assessment were consistent with the results of pre-injection laboratory studies, which showed rapid dechlorination of target chlorinated compounds accompanied by a sharp decrease of standard oxidation potential and an increase in pH.

A phase 2 clinical trial comparing Ro 48-6791, a new short-acting benzodiazepine, with propofol for induction of anaesthesia.

A phase 2, single-blinded, randomized, multicentre trial was conducted to compare recovery times from anaesthesia between patients induced with a new short-acting benzodiazepine Ro 48-6791 (Hoffman-La Roche, Sydney, N.S.W.) or propofol. Seventy-six patients were randomly allocated to receive either Ro 48-6791 or propofol for induction followed by a standardized anaesthetic. Alertness and ambulatory function during recovery were scored by a rater blinded to treatment group. Mean time to awakening was longer for the Ro 48-6791 group (15 min), compared with propofol (7 min, P < 0.001), as was mean time to full clinical recovery (116 min vs 75 min respectively, P = 0.002). Both groups showed similar cardiovascular stability following induction, but shorter apnoea times were demonstrated for Ro 48-6791 (48s vs 133, P < 0.001). The longer recovery times with Ro 48-6791 would make this drug a less suitable sole induction agent than propofol for routine use in day stay surgery. Further studies of Ro 48-6791 should pay particular attention to the effect of dose reduction on recovery profile.

Sudden onset of subarachnoid block after subdural catheterization: a case of arachnoid rupture?

We describe a patient who received an apparently uneventful extradural block in labour but developed rapid extension of neural block within minutes of receiving her first incremental dose 2 h later. Computed contrast tomography revealed radio-opaque dye within both the subdural and subarachnoid spaces, but none within the extradural space. This case report demonstrates that subdural spread of low-dose local anaesthetics is not always clinically distinguishable from extradural analgesia and that the arachnoid membrane may subsequently perforate with potentially serious consequences.

Are pancreatoenteric anastomoses improved by duct-to-mucosa sutures?

The patency of anastomoses joining the pancreas to either a Roux-Y loop of jejunum or the stomach was evaluated in 26 dogs. At a preliminary operation, the head and uncinate process of the pancreas were resected while carefully preserving the duodenal blood supply. The remaining body and tail of the pancreas were totally obstructed. After obstruction for a mean of 22 (range: 6 to 42) days, one of three anastomoses was performed: (1) inversion pancreatogastrostomy with two layers of sutures; (2) a similar inversion pancreatojejunostomy to the side of a Roux-Y jejunal loop; or (3) pancreatojejunostomy in which the major duct was joined to the jejunal mucosa with interrupted sutures. Six animals were kept for controls. Anastomotic patency was assessed after 8 to 12 weeks by pancreatography, with minimal pressures to achieve anastomotic flow recorded. Weight trends were consistent with anastomotic status. The eight dogs with duct-to-mucosa sutures clearly achieved superior anastomotic patency.

Reassessment of primary resection of the perforated segment for severe colonic diverticulitis.

Primary resection with colostomy has been widely adopted during the past decade for the treatment of patients with severe complications of diverticulitis. Because of this, a retrospective review was performed of all patients undergoing surgery for colonic diverticular disease during the two time periods 1974 to 1978 (n = 196) and 1982 to 1986 (n = 230). Forty-three patients had abscess or peritonitis from 1974 to 1978, whereas 52 had these complications from 1982 to 1986. Colostomy and drainage alone were used for 31 of 43 patients (72%) from 1974 to 1978, while primary resection with colostomy was used for 39 of 52 patients (75%) from 1982 to 1986 (p less than or equal to 0.5). Despite this shift in treatment method, mortality increased from 14% in 1974 to 1978 to 19% in 1982 to 1986 (p = NS). Patients with peritonitis had identical mortalities (22%) during both intervals. Patients with abscess experienced an increase in mortality from 8% in 1974 to 1978 to 15% in 1982 to 1986 (p = NS). The widespread use of primary resection for patients with severe complications of diverticulitis appears not to have altered mortality for those with diffuse peritonitis and may have worsened the outcome for those with abscess.

A statistical analysis of drainage versus nondrainage of elective cholecystectomy.

A retrospective review is undertaken to evaluate the effects of drainage versus nondrainage of the gallbladder bed after elective cholecystectomy. Two hundred charts of patients who underwent elective cholecystectomy without choledochotomy were reviewed. Patient selection was based upon several criteria: elective cholecystectomy, lack of explorations of the common duct and lack of associated surgical procedures. Two equal groups were analyzed. Those who had postoperative drainage of the subhepatic space and those who did not have drainage. Postoperative length of stay, maximum postoperative temperature elevation and the number of postoperative analgesics were significantly higher (p less than 0.001) in the drainage group. The rate of progression to regular diet was significantly faster in the nondrainage group (p less than 0.001) and the number of complications was higher in the drainage group (p less than 0.05). No complications were noted due to the lack of drain placement. It was concluded that routine drainage of the subhepatic space after elective cholecystectomy without choledochotomy is unnecessary and contributes to increased postoperative morbidity, length of hospital stay and a higher rate of complications.

Surgical aspects of Clostridium septicum septicemia.

Clostridium septicum is a virulent cause of gas gangrene and sepsis. Although thought to be rare, a survey of our affiliated hospitals for a recent five-year period disclosed eight cases. Seven of the eight had an occult malignant neoplasm. The eighth patient was thought to be preleukemic. All seven malignant neoplasms involved the gastrointestinal tract. Four patients were admitted with gangrene of an extremity, three with abdominal pain, and one with both. In four patients, C septicum septicemia appeared in an extremity before the underlying gastrointestinal malignant neoplasm was recognized. Four patients had surgical therapy and two survived; four received medical therapy and one survived. Patients who have C septicum septicemia should be assumed to harbor an underlying malignant neoplasm until proved otherwise.

Comparison of weight loss after gastric exclusion and partitioning.

We report follow-up findings after two to almost four years on 100 patients who were described in a previously published prospective randomized series. Horizontally stapled gastric partition (gastroplasty) was compared with gastric exclusion (bypass) using a Roux-en-Y jejunal loop. An additional 142 patients had the identical operative procedures performed during the same time period, but chose their own operation. Both procedures used a small gastric pouch (15 mL) and calibrated 10-mm opening. Weight loss was better after exclusion and has continued to be better. Patients who lose weight well do not regain. There were complications in 8% of the exclusion patients and 12% of the partitioning patients and one death in the exclusion group--0.4% of the total group. Since gastric exclusion is safe and produces significantly better weight loss, we believe it sets the current standard against which all other bariatric surgery must be compared.

Survival following extended operations for extracolonic invasion by colon cancer.

Of 460 cases of colon cancer treated between 1972 and 1976, 24 were unusual. These patients required en bloc resection of the colon with one or more adjacent organs for dense adhesions between the colon and these organs. In 66% of the cases these adhesions represented microscopic tumor invasion. Lymph nodes were positive for disease, stage C-3, in only four specimens. The pathologic features of the tumor were well differentiated in 87%. The operative mortality was 8% and two patients died of recurrent disease one and three years postoperatively. One man is alive seven years postoperatively with recurrent disease. Nineteen patients (79%) are alive five to nine years following surgery with no evidence of disease. A comparison with patients with similarly staged Dukes' B and C disease shows a substantially improved survival at five years when extended operation is performed.

Prospective controlled study of gastrointestinal stapled anastomoses.

A controlled prospective study was carried out in a university-affiliated community hospital to evaluate the use of gastrointestinal staples compared with conventional sutures for anastomotic construction. The study included 100 randomized cases (50 sutured and 50 stapled) requiring anastomoses. Consecutive patients were accepted into the study, and no patients were excluded. There was no significant difference between the two groups in operating room time or the duration of postoperative hospitalization, nasogastric intubation or intravenous intubation. The complication rate was similar and comparable to previously published results. On three occasions, it was necessary during operation to convert from the use of staples to sutures when immediate disruption was noted at a gastroduodenal anastomosis.

Biliary tract surgery.

Postoperative wound infection rates after biliary tract surgery vary tremendously from 2% after uncomplicated cholecystectomy to 20% in series including many jaundiced patients. Almost all such infections arise from organisms growing in the diseased biliary tract, since infection rate of 1% are achieved when the bile is sterile. A history of cholangitis identifies only one third of the patients with infected bile, but four easily recognized clinical factors point to positive bile cultures in 60% to 75% of patients: (1) age over 70, (2) obstructive jaundice, (3) common duct stones without jaundice, and (4) emergent acute cholecystitis. These selected high-risk patients have postoperative infection rates of 20% to 27%. Preoperative administration of cephaloridine reduced this high rate of infection to 5% in a prospective randomized but not blinded trial. The initially reported experience of 84 patients has been extended to 140 and continues to confirm the efficacy of prophylactic antibiotics in selected high-risk patients. In contrast, there is no present evidence supporting the use of antibiotic prophylaxis in low-risk patients under 70 years of age undergoing uncomplicated cholecystectomy.

Role of gastrin determinations in clinical surgery.

Patients with recurrent ulcer without retained antrum and with a complete vagotomy will have a low gastric acid output. Those with incomplete vagotomy and gastric resection will have a fasting and histamine-stimulated gastric acid output which are normal' this is as though they had no previous gastric operation. Both groups of patients will have a normal fasting and postprandial serum gastrin. Patients with recurrent ulcer associated with retained antrum will have a fasting and histamine-stimulated acid output above normal. In the latter, fasting serum gastrin will be increased twice normal but not as markedly increased as found in Zollinger-Ellison syndrome. Patients with retained antrum will have a marked postprandial increase in serum gastrin about two times the fasting level. Those patients with this syndrome will have markedly elevated fasting and histamine-stimulated gastric acid as well as marked hypergastrinemia.

Gastrin determinations in symptomatic patients before and after standard ulcer operations.

Whereas 67 patients with duodenal ulcer had fasting and 30-minute postprandial mean serum gastrin levels not substantially different from 32 normal subjects, they had substantially higher fasting and histamine-stimulated gastric acid secretion. The increased acid secretion found in patients with duodenal ulcer is not caused by increased serum gastrin levels. Ten patients with recurrent ulcer, after incomplete vagotomy and gastric resection, had high gastric acid secretion and normal serum gastrin levels. Three patients with recurrent ulcer following complete vagotomy and gastric resection, but with retained antrum, had both high gastric acid secretion and high fasting and postprandial secrum gastrin levels. Three patients with Zollinger-Ellison tumors had even higher basal acid outputs and serum gastrin levels. The combination of basic gastric acid secretory studies and serum gastrin determinations may identify three causes of recurrent ulcer: incomplete vagotomy, retained antrum, and Zollinger-Ellison tumor.

Hemorrhage due to diffuse erosive gastritis.

Of 796 patients admitted with upper gastrointestinal bleeding during a five-year period, 156 (20%) had erosive gastritis. Vigorous nonoperative treatment stopped bleeding in 117 (75%); emergency operation was required in 39 (25%). In 24 of these 39 patients (group A), subtotal gastric resection with truncal vagotomy was performed. In the remaining 15 patients (group B), the operation was limited to pyloroplasty, truncal vagotomy, and multiple suture ligation. These patients were, on the average, 20 years older than the patients in group A, and 12 had life-threatening preoperative problems. (Only four of the group A patients had life-threatening preoperative problems.) The operative mortality in group A was 42%, with rebleeding occurring 33%. In group B, only 17% rebled and the operative mortality was 45%. Survival in the two groups was similar, even though those patients in group B were more critically ill. The less radical procedure may often be the best choice in the high-risk and elderly patients who bleed massively and in whom immediate salvage of life is the main issue.