Asbestos fibers in parenteral medication.

The adequacy of current regulations for the control of particulate matter in injectable medicines has been brought into question by a recent television program which reported that asbestos fibers had been found in a number of such preparations. The fibers were identified as chrysotile, which occurs very widely as a secondary mineral in rocks, and is almost ubiquitous among minerals derived from natural erosion. Fibers are found in almost all drinking water and air samples unrelated to any contamination of fiber resulting from industrial exploitation. Because of this, even extreme laboratory precautions may fail to eliminate every fine fiber. A normal person living in an urban environment inhales about 10(5) asbestos fibers daily and ingests 10(10). There is evidence that a small proportion of these fibers regularly enters the circulation, and some fibers may be excreted in the urine. Elimination also occurs because retained chrysotile fibers fragment and disappear relatively quickly from human tissues, probably through macrophage action. Fiber length and dose are also important in disease causation. Established evidence on fiber length, durability, and quantitative exposure required for disease production does not indicate that the fibers reported to have been found in parenteral preparations constitute any hazard.

Carcinogenicity of the insulation wools: reassessment of the IARC evaluation.

In assessing the health evidence concerning man-made mineral fibers, the chemical composition, surface activity, durability, and size of fibers have to be taken into account. Special-purpose fine glass fibers need to be separated from the insulation wools (glass, rock, and slag wool). The epidemiological evidence is sufficient to conclude that there has been no mesothelioma risk to workers producing or using glass wool, rock wool, or slag wool. The epidemiological studies have been large and powerful, and they show no evidence of a cause-effect relationship between lung cancer and exposure to glass wool, rock wool, or slag wool fibers. There is some evidence of a small cancer hazard attached to the manufacturing process in slag wool plants 20 to 50 years ago, when asbestos was used in some products and other carcinogenic substances were present. However, this hazard is not associated with any index of exposure to slag wool itself. Animal inhalation studies of ordinary insulation wools also show that there is no evidence of hazard associated with exposure to these relatively coarse, soluble fibers. The evidence of carcinogenicity is limited to experiments with special-purpose fine durable glass fibers or experimental fibers, and only when these fibers are injected directly into the pleural or peritoneal cavity. Multiple chronic inhalation studies of these same special-purpose fine glass fibers have not produced evidence of carcinogenicity. It is suggested that the present IARC evaluation of the carcinogenic risk of insulation wools should be revised to Category 3: not classifiable as to carcinogenicity to humans.

Asbestos-related benign disease and cancer: symptoms and treatment.

Long lasting occupational exposure to asbestos dust may cause skin corns, benign pleural effusion, hyaline plaques of the parietal pleura, diffuse thickening of the pulmonary pleura, and asbestosis, i.e. diffuse interstitial pulmonary fibrosis. Malignant disorders include lung cancer and mesothelioma of the pleura, peritoneum and pericardium. In general, many years elapse from first exposure to the appearance of symptoms. Almost all these diseases are the result of dusty working conditions more than 20 years ago. In spite of the fact that the general public is invariably exposed to small amounts of the material, asbestos is not a public health problem. Even living in a building containing sprayed asbestos is calculated to produce a lifetime risk of death which is negligible. There is no evidence to indicate that ingested asbestos fibres represent a major health problem.

What every surgeon should know regarding asbestos-related disease.

Long-lasting occupational exposure to asbestos dust may cause pleural disease, asbestosis, bronchogenic carcinoma and mesothelioma. Many years elapse from first exposure to the appearance of symptoms. Almost all these diseases are the result of dusty working conditions 20-40 years ago. The pathological sequelae are usually irreversible and can progress after exposure ceases. There is no satisfactory treatment. Prevention is the only practical way. In spite of the fact that the general public is invariably exposed to small amounts of the material, asbestos is not a public health problem. Exemptions are the buildings not properly cared for containing sprayed asbestos. But even living in such buildings is calculated to produce a negligible risk of death. Asbestos-related diseases occur where long-lasting inhalation of high amounts of fine asbestos dust has occurred. There is no evidence to indicate that ingested asbestos fibers represent a major health problem. Industry is now replacing asbestos in many products by other fibers. Natural and synthetic organic materials used in fiber cement products are unable to reach the alveoli. They are not cancerogenic and there is no reason to believe that such fibers cause chronic pulmonary disease.

Prevention of fatal pulmonary embolism in patients with fractures of the neck of the femur.

Patients with fractures of the neck of the femur have an extremely high incidence of venous thrombosis and pulmonary emboli, if not receiving prevention with drugs. From a prospective, randomized multicenter trial comparing the effectiveness of two methods for the prevention of postoperative fatal pulmonary emboli, we analyzed those patients having been operated upon for a fracture of the neck of the femur. One hundred and seventy-two patients having had heparin-DHE prevention and 157 having had dextran prevention are compared with 150 patients in the control group and 165 patients who were given phenindione for anticoagulation orally. The data from the latter two groups stem from a study done in 1959 by Sevitt and Gallagher which for the first time established the value of oral anticoagulation for reducing pulmonary emboli. All three prophylactic methods reduce the incidence of pulmonary emboli to the same degree. The mortality associated with pulmonary emboli is 2 per cent in the phenindione group, 2.3 per cent in the heparin-DHE group and 3.8 per cent in the dextran group, in contrast with 10 per cent in the control group. Total mortality has been lowered significantly in all three groups as compared with the control group. Fatal pulmonary emboli were found only when prophylaxis had been stopped or was incomplete and were not found when prophylactic regimen was done properly. In 1980, the hospital stay was about one week shorter than in 1959.

Prevention of thrombo-embolic complications in paraplegics.

We have analysed 11 studies dealing with thrombo-embolic complications and their prevention in paraplegics. The incidence of deep vein thrombosis in a total of 1316 hospitalized patients (not receiving any sort of specific prevention), lies between 13 per cent when the diagnosis is made on clinical grounds alone, and reaches 84 per cent when a fibrinogen test and phlebography are carried out routinely. In 904 patients not receiving prevention pulmonary emboli occur in 4-15 per cent, but in only two studies were autopsies carried out. It is most likely that thrombo-embolic complications in paraplegics are even more common than in orthopaedic patients. Five studies dealt with prevention of thrombo-embolic complications; three with oral anticoagulation, two using physical methods, one dealing with subcutaneous heparin and one testing platelet inhibitors. None of the studies published so far is controlled, prospective and randomized at the same time, and uses objective diagnostic methods. Since all studies show one or more methodological problems, it is impossible to make clear statements regarding the relative effectiveness of various prophylactic methods in this type of patient. The apparently extremely high risk for thrombo-embolic complications, however, would make routine prevention in paraplegics mandatory.

[In which operations is antibiotic prevention carried out with only a a single dose? Results of a survey among chief physicians in general surgery in German-speaking Switzerland]. / Bei welchen Operationen wird eine Antibiotika-Prophylaxe mit nur einer Dosis durchgeführt? Ergebnisse einer Umfrage unter allgemeinchirurgischen Chefärzten der deutschsprachigen Schweiz.

We have been asking 108 surgeons in chief of the German speaking part of Switzerland in what operations they are giving an antibiotic prophylaxis. We wanted to know how far the application of the single-dose concept has been entering every day's practice in Switzerland. Its value has been proven in several prospective, randomized, controlled studies. Out of 84 valid questionnaires we could see that single-dose prophylaxis has not yet come into common use, although it is not only more reasonable but also less expensive than a prolonged course. Fortunately, already 90% of the surgeons are giving an antibiotic prophylaxis in colorectal surgery and 53% in biliary tract surgery. A majority of surgeons do not yet provide antibiotic prophylaxis in gastric surgery nor in appendectomies, where the single-dose prophylaxis is effective as well.

[The value of heparin-dihydergot in the prevention of thromboembolic complications]. / Wert von Heparin-Dihydergot zur Prophylaxe thromboembolischer Komplikationen.

57 papers dealing with the prevention of postoperative thromboembolic complications have been analyzed. They comprise 28 prospective, randomized, comparative studies using objective diagnostic techniques. 2 X 5000 IU daily of heparin-DHE lowers the incidence of deep vein thrombosis in general surgery, thoracic surgery and gynecology significantly better than 2 X 5000 IU heparin alone. In hip surgery 3 X 5000 IU heparin-DHE is more effective than the same amount of heparin alone. In the entire field of orthopedic surgery, heparin-DHE, in a dosage of 2 X 5000 IU, lowers the incidence of fatal pulmonary emboli just as well as dextran 70. With regard to prevention of deep vein thrombosis in general surgery, there is no statistically significant difference between prevention with 2 X 2500 IU heparin-DHE and 2 X 5000 IU heparin. 2 X 2500 IU heparin-DHE significantly lowers the incidence of bleeding complications in general surgery, as evaluated in double-blind studies and compared to 2 X 5000 IU heparin alone.

Prevention of thromboembolic complications with miniheparin-dihydroergotamine in patients undergoing lumbar disc operations.

We have evaluated the incidence of bleeding complications using miniheparin (2 X 2500 IU daily)-dihydroergotamine starting preoperatively in a randomized, controlled, prospective, double-blind study in 50 patients undergoing herniated lumbar disc operations. There was no difference in the incidence of intraoperative bleeding problems between the two groups. Preoperatively, 13 patients have been treated in another hospital with conventional low-dose heparin, and of these 13 patients, 7 developed bleeding complications. There were two deep wound hematomas in the placebo group. Early removal of stitches or operative revision of the wound was not necessary in either group. We conclude that the use of minidose heparin-dihydroergotamine is feasible for the prevention of thromboembolic complications in patients undergoing herniated lumbar disc operations, since an increased incidence of bleeding complications was not observed. This preventive method should therefore be further clinically evaluated.

[Should antibiotic prevention be used in biliary tract surgery?]. / Soll man in der Gallenwegchirurgie eine Antibiotika-Prophylaxe machen?

A prospective, controlled, double-blind, randomized multicentre trial in Switzerland has been conducted to investigate the effectiveness of 5 g mezlocillin given during induction of anesthesia for prevention of infectious complications in biliary tract surgery. All adults undergoing elective or emergency surgery were included. Single-dose prevention reduces the incidence of wound infections from 10% to 4%, but does not reduce other kinds of infectious complications. The incidence of wound infections in the control group in Switzerland is only about half that in other countries. It is concluded that administration of single-dose mezlocillin to all patients in this type of surgery is justified. On the basis of risk factors it is impossible to predict reliably the patients who do not need protection.

[Perispinal anesthesia and subcutaneous administration of low-dose heparin-dihydergot for prevention of thromboembolism]. / Rückenmarksnahe Anaesthesie und subkutan verabreichtes low-dose Heparin-Dihydergot zur Thromboembolieprophylaxe.

The risk of haematoma formation in the spinal canal following spinal or epidural anaesthesia given in the presence of s.c. heparin-dihydroergotamine (DHE) for prevention of postoperative thromboembolic complications was examined. The data were obtained from a study that compared the effectiveness of s.c. heparin-DHE and i.v. Dextran 70. Heparin-DHE was administered two hours before anaesthesia and surgery and during the postoperative course. All patients underwent elective or emergency operations of the musculo-skeletal system. The s.c. heparin-DHE group consisted of 187 patients operated under spinal (82 patients) or epidural (105 patients, 66 of whom received an epidural catheter) anaesthesia. There were no clinical signs to suggest the presence of an epidural haematoma nor were there any neurological symptoms. The same was true in the dextran group. Specific neurological examinations were not carried out, but the clinical results were controlled by means of a questionnaire filled out by the patients 6 weeks postoperatively. We conclude that s.c. heparin-DHE or i.v. dextran 70 has been used safely in the presence of spinal or epidural anaesthesia in these patients.