Continued from page 1.
* Glove quality. Denise M. Korniewicz, D.N.Sc., R.N., director, acute care, graduate program, Johns Hopkins School of Nursing, and widely considered the "glove guru," presented a study on the use of double-gloving for added protection. Dr. Korniewicz had been firt to identify the problem of high rates of failure in many brands and materials of disposable examination gloves. Her earlier findings were influential in the FDA's decision to make glove manufacturers' testing criteria more stringent.
Dr. Korniewicz's new study found that latex brands leaked less than vinyl varieties. She found no advantage to double-gloving with latex, since the first pair held up well and the second offered no additional protectin. Leakage was substantially less, however, when vinyl brands were doubled. [8]
Having to wear two pairs of vinyl gloves as contrasted with only one pair of latex "makes wearing vinyl gloves much more expensive in the long run" despite the originally lower price of vinyl ones, Dr. Korniewicz told MLO. The next phase of her research, she said, will include an extensive study on gloves that are used during surgical procedures.
* Lab-acquired HIV. As of the time of the conference, 24 cases of occupationally acquired HIV infection in the United States had been documented. An additional 16 were suspected but could not be documented because no base-line specimen had been taken at the time of exposure.
Russ Metler, R.N., M.S.P.H., a nurse epidemiologist at the division of HIV/AIDS at the CDC, presented a study showing that lab workers represent nearly one-third (32%) of all cases of overt AIDS due to HIV received at work. That makes laboratorians the second-highest subgroup in that category; the largest is nurses. Phlebotomy (including arterial blood sampling), representing 50% of all health care exposures, was the single most dangerous work-related activity cited. Manipulation of intravenous devices or sites was the cause of 36% of exposures; manipulation of lab equipment, 9%. [9]
* AZT. Jerome Tokars, M.D., M.P.H., an epidemiologist at the CDC's hospital infection program, updated attendees on the Federal cooperative needlestick surveillance study. From October 1988 to April 1991, Dr. Tokars said, 1,525 health care workers potentially exposed to HIV were tested at baseline and six months or more after exposure. Four of 1,346 in a subset of those injured via needlesticks or cut with a contaminated sharp object seroconverted and became infected.
Seroconversion took place in none of the 179 health care workers who were exposed through a mucous membrane of nonintact skin. From October 1988 to April 1991, 123 health care workers used Zidovudine (azidothymidine, or AZT) and completed at least a six-week follow-up. Although none of these study subjects had seroconverted when last tested, it is too soon to predict the efficacy of the drug in halting the progress of the virus.
Seventy percent of those taking AZT experienced at least mild symptoms, including nausea, malaise, headache, or vomiting; 2% experienced anemia. Adverse effects caused 36% to discontinue treatment. All symptoms of the drug were reversible.
A 100-mg median daily dose of AZT was given over a median period of 42 days. The median interval from exposure to HIV-infected material to the time of receiving the first dose of the drug was six hours, an average derived from a broad range: Five minutes to 17 days.
Prophylactic use of ACT for health care workers exposed to HIV continues to be debated with passion. It will take many years to assess the efficacy of the drug adequately. [10]
* The (in)famous dentist. Partly because of fast-breaking news about a few dentists in the United States, the hottest topic at the conference was infection with HIV in patients from physicians, dentists, or other health care workers. Donald Marianos, D.D.S., M.P.H., dental officer for the Center for Prevention Services at the CDC, conducted a follow-up investigation of the cluster transmissions of HIV by a now-deceased Florida dentist that have led to at least five cases of HIV infection in his former patients.
Dr. Marianos said that although the exact mechanisms of transmission in these cases had not been established, recommended biosafety procedures had clearly been breached in his dental practice in several ways. Gloves and other disposable items, for example, were frequently washed and reused. Siloxane injectors, used in making impressions from teeth and crowns, and prophylactic cups, which are fitted to the ends of drills used in cleaning teeth, were immersed in germicides for indefinite periods and reused.
The dentist employed no established infection control or biosafety protocol in his office and provided no biosafety training to his office staff. [11] The staff did indicate verbally, however, that the dentist's own biosafety practices improved over time.
James A. Cottone, D.M.D., M.S., professor and director of the division of oral diagnosis and oral medicine at the University of Texas Health Science Center, San Antonio, conducted an international survey of dentists' knowledge about HIV and infection control practices. Dr. Cottone told MLO that the Florida dentist "was probably very average for what dental practice was like during those years--1986 to 1988--and possibly today."
Criticizing CDC guidelines as vague and general, Dr. Cottone stressed the need for discipline-specific recommendations. He concluded that the mode of transmission from the Florida dentist was still unclear and might never be known. [12]
Commenting privately later, Dr. Gershon said Dr. Marianos's report "reaffirms everything we believe in with respect to the need to establish basic infection control procedures." She emphatically stated, "This is what happens when there is a universal lack of compliance with universal precautions." Research on establishing better engineering controls and safer devices, she added, is sorely needed.
* Rish of reverse transmission. Attracting considerable attention at the conference were efforts to gauge the risk of HIV transmission to patients during invasive medical procedures. Albert B. Lowenfels, M.D., professor of surgery and of community and preventive medicine at New York Medical College, Valhalla, N.Y., estimated the risk from surgeon to patient. According to his calculations, the risk to a surgeon or to another member of the operating team of receiving a puncture injury during a single invasive procedure was greater than one in 100.
Taking a conservative stance, Dr. Lowenfels estimated that at most, one in 200 surgeons across the United States is now HIV positive. He suggested that the risk of HIV transmission to a patient from an HIV-positive surgeon after a single needlestick, scalpel cut, or similar injury in the operating room was 1.5 in 1,000--half the risk factor for health care workers of contracting HIV from an infected patient during a single injury (3:1,000).
One reason transmission from surgeon to patient is less likely than from patient to surgeon is that during an invasive procedure the surgeon is virtually bathed in the patient's blood. The patient, however, is exposed to a far lower volume, if any, of the surgeon's blood, even if the surgeon has incurred a percutaneous injury.
A second reason for the low probability of reverse transmission is that most seroconversions in health care workers to date have resulted from punctures with hollow needles, which can hold substantially more blood than the solid needles, sutures, and scalpels used during surgery.
Third, during surgical procedures, the external surface of a solid needle is often wiped virtually clean by the surface of the glove before the point can pierce the skin. This series of events lowers the inoculum.
When a surgeon's HIV status is unknown, the overall probability of reverse transmission is obtained by multiplying all independent risks together. In the study by Dr. Lowenfels, that risk was calculated at one in 1.3 million. The investigator deduced that reverse transmission might lead to HIV infection in four to five of the 27 million operations performed annually in the United States.
David M. Bell, M.D., chief of AIDS activity in the CDC's hospital infections program, conducted a study similar to the one by Dr. Lowenfels. Dr. Bell estimated that from 1980 to 1990, 12 to 129 patients had acquired HIV from infected surgeons or dentists.
The CDC was harshly criticized by members of the audience for having promulgated guidelines they considered far too broad and vague. In response, Dr. Bell called the current guidelines "suboptimal" and "needing revision," which he said was in progress. He indicated, however, that the new recommendations were "controversial" and "required higher and higher levels of approval" before they could be released. "It gets delayed," he admitted. [13]
Start Of Article
« Previous 1 2 3 Continued »
