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Biomedical subjects

D K Henderson

Publications and source records attributed to D K Henderson.

At least 55 records · Page 3Linked to original sources

Adverse exposures and universal precautions practices among a group of highly exposed health professionals.

An anonymous national survey of a representative population of healthcare workers who were thought likely to have frequent and intensive exposures to blood and other body fluids (certified nurse-midwives [CNMs]), was conducted to assess the type and frequency of self-reported occupational exposures to blood and body fluids experienced, the extent to which barrier precautions and other infection control measures were used, whether or not reported use of barriers was associated with a lower perceived rate of exposures and factors that influenced the use of infection control procedures. Of those responding, 74% had soiled their hands with blood at least one time in the preceding six months, 51% had splashed blood or amniotic fluid in their faces and 24% reported one or more needlestick injuries during that same period. Our study also found evidence of an association between the practice of needle recapping and the occurrence of needlestick injury (p = .003). Despite a high level of training and knowledge, only 55% reported routinely practicing universal precautions (UPs). Several factors that potentially influenced the use of UPs were studied, including healthcare worker perceptions of risk of occupational bloodborne infection, knowledge of routes of transmission of bloodborne pathogens and rationale for not using appropriate barriers. Our data suggest that occupational exposures occur frequently and that healthcare workers' (HCWs') perceptions of risk for occupational infection play an important role in influencing use of UPs. This study emphasizes the importance of developing new strategies for UP training.

Acquired Immunodeficiency Syndrome↗

Risky business: using necessarily imprecise casualty counts to estimate occupational risks for HIV-1 infection.

Although the genesis of healthcare worker anxiety regarding occupational risks of HIV-1 infection is clear, the reasons for continued insistence on a meticulous "casualty count" become less clear with time. One could, in fact, argue that the precise number of such infections has become virtually meaningless, because the routes of occupational/nosocomial transmission of HIV-1 and the magnitude of risk for infection following an adverse exposure in the healthcare setting have been well-characterized. Nevertheless, with the substantial limitations of these data clearly in mind, we have summarized the numbers of healthcare workers reported to have HIV-1 infection in each of the above categories in Table 2. The likelihood that an individual case represents true occupational infection decreases as one moves down the table. Having waded through the depths of this literature, we have reached the conclusion that, of the available data, the magnitude of risk for occupational HIV-1 infection remains the single most useful and instructive statistic available. Longitudinal cohort studies of HCWs involved in the day-to-day care of HIV-1-infected patients and in the handling and processing of specimens from such patients provide the best available evidence regarding the magnitude of risk for transmission of this virus in the healthcare setting. Fourteen prospective studies are currently in progress, with approximately 2,000 HCWs enrolled (Table 4). Six HCWs enrolled in these studies have developed serologic evidence of HIV-1 infection following percutaneous exposures, yielding an infection rate per participant of 0.32% and an infection rate per exposure of 0.31%.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗

Potential for laboratory exposures to biohazardous agents found in blood.

The magnitude of risk for occupational exposures to biohazardous agents found in blood was assessed by 800 environmental samples taken from a total of 10 clinical and research laboratories at the National Institutes of Health (NIH). Thirty-one samples from 11 work stations in three laboratories contained hepatitis B virus surface antigen (HBsAg). Observations of workers indicated that environmental contamination arose from several sources. Among the 11 work stations with HBsAg environmental samples, eight had high work loads, seven had inappropriate behaviors, and nine had flawed laboratory techniques. This information suggests that a multifactorial approach is needed to minimize the risk of laboratory-associated infections.

Blood↗

Prophylactic zidovudine after occupational exposure to the human immunodeficiency virus: an interim analysis.

Note from Dr. Merle A. Sande--Health care workers are at risk of acquiring human immunodeficiency virus (HIV) infection subsequent to accidental sticks with needles contaminated with blood from infected patients. The risk is small but real. Postexposure management is critically important, but few solid data are available. Can zidovudine (AZT, azidothymidine) prevent infection? How soon after exposure must the drug be given? At what dosage? For how long? Two leading authorities were asked to discuss this problem and to offer recommendations. Both have developed programs in their institutions, Dr. David K. Henderson at the Warren Grant Magnuson Clinical Center at the National Institutes of Health and Dr. Julie L. Gerberding at the University of California, San Francisco.

Acquired Immunodeficiency Syndrome↗

Admission of AIDS patients to a medical intensive care unit: causes and outcome.

As the number of cases of AIDS increases, it is important to determine whether ICUs can be productively and safely used for this patient population. From July 1981 to March 1987, 216 patients were admitted to the medical ICU: 166 (77%) were admitted for procedures and 50 (23%) were admitted for life-sustaining support. Most of the patients were admitted for respiratory failure (36 of 50), primarily as a result of Pneumocystis carinii pneumonia. Other patients were admitted for cardiovascular instability (six of 50 patients), CNS dysfunction (four patients), or other reasons (four patients). Of 50 patients admitted to the ICU, 13 (26%) were alive 3 months after hospital discharge. Despite 25 needle-stick injuries and 56 mucosal splashes involving human immunodeficiency virus (HIV)-infected patients and staff, no staff member converted HIV serology. These results suggest that AIDS patients may benefit from ICU admission. These patients appear to pose a low risk to the hospital staff in terms of occupationally acquired HIV infection, but strong emphasis needs to be placed on minimizing accidental exposures to potentially infected body fluids and to adhering to universal precautions.

Acquired Immunodeficiency Syndrome↗

Indolent epidemic of Pseudomonas cepacia bacteremia and pseudobacteremia in an intensive care unit traced to a contaminated blood gas analyzer.

An epidemic of Pseudomonas cepacia bacteremia and pseudobacteremia occurred in the medical intensive care unit at the Clinical Center of the National Institutes of Health. Sixteen patients in the intensive care unit became colonized or infected with this organism in a 21-month period; whereas P. cepacia had been isolated only 16 times in the preceding 90 months from the entire hospital. Further analysis demonstrated a significant association of the epidemic cases with bloodstream isolation of the organism (p less than 0.001, Fisher's exact test). Mortality associated with bacteremia caused by P. cepacia was 38 percent. Intensive investigation of the intensive care unit and its surrounding environment eventually demonstrated that a blood gas analyzer in a satellite laboratory adjacent to the intensive care unit was the reservoir for the outbreak. Replacement of the machine resulted in termination of the outbreak, P. cepacia continues to represent an environmental threat to hospitalized patients.

Blood Gas Analysis↗

Chronic fungal sinusitis in apparently normal hosts.

Several fungal species are capable of causing either noninvasive fungal sinusitis or invasive disease characterized by erosion into mucosa, submucosa, bone, and deeper contiguous structures. The diagnosis of invasive infection becomes firmly established only after histologic demonstration of hyphae within these areas. Computerized tomography and magnetic resonance imaging can assist in distinguishing between invasive and noninvasive disease by outlining bone and adjacent structures. The 2 forms of chronic fungal sinusitis mandate different therapeutic approaches. While patients with noninvasive infection require only surgical removal of hyphal masses and the reestablishment of sinus drainage for a successful outcome, invasive infection necessitates not only thorough surgical debridement of abnormal tissues but may also require prolonged antifungal chemotherapy. All patients require long-term follow-up. Even the combined approach has sometimes proven disappointing during long-term follow-up of disease, rendering investigational therapy appropriate in some patients.

Adult↗

Nosocomial transmission of hepatitis A in an adult population.

Nosocomial transmission of hepatitis A from patients to staff members is an unusual event. Recently, several cases of occupational transmission of hepatitis A to health care workers have been reported in the literature. Most of these have occurred as a result of transmission from an infected child to a staff member involved in his or her care. We report an additional case of transmission of hepatitis A from an infected adult to a staff member and review the literature regarding nosocomial hepatitis A transmission. The review emphasizes several points that nearly all instances of nosocomial transmission of hepatitis A have in common, including the role of asymptomatic infection, the timing of hospitalization, and the fact that index patients often have an underlying illness that obscures the early diagnosis of hepatitis A. In addition, several other areas of controversy with respect to hepatitis A are discussed.

Adult↗

Bioassay for SF 86-327, a new antifungal agent.

A bioassay with Trichophyton mentagrophytes is described for SF 86-327, an allylamine antifungal agent. SF 86-327 serum concentrations were measured by bioassay in 117 serum sampler from five patients receiving 500 mg/day. The peak, trough, and area under the concentration-time curve were determined after the first dose and at steady state. Drug accumulation occurred with prolonged therapy.

Antifungal Agents↗

Risk of nosocomial infection with human T-cell lymphotropic virus type III/lymphadenopathy-associated virus in a large cohort of intensively exposed health care workers.

To assess the risk of nosocomial transmission of human T-cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV), we prospectively evaluated a cohort of 531 health care workers. One hundred fifty of these employees reported percutaneous or mucous membrane exposures to blood or body fluids from a patient with the acquired immunodeficiency syndrome (AIDS) during the treatment of 238 such patients since 1981. None of these 150 employees had serologic evidence of HTLV-III/LAV infection on follow-up from 6 to 46 months after exposure. Of the 150, 46 were studied immunologically and 29 had lymphocytes cultured for HTLV-III/LAV. Results of all studies were normal. Of the 531 employees, 3 (0.56%) had serologic evidence of HTLV-III/LAV infection. All were seropositive at the time of study entry; none reported adverse nosocomial exposures. All acknowledged membership in one or more established risk groups for AIDS. This study provides strong evidence that the risk of nosocomial transmission of HTLV-III/LAV is extremely low.

Acquired Immunodeficiency Syndrome↗

Tolerance to cryptococcal polysaccharide in cured cryptococcosis patients: failure of antibody secretion in vitro.

Ten patients cured of cryptococcosis and 14 normal volunteers were immunized with subcutaneous injections of cryptococcal polysaccharide (CPS). Peripheral mononuclear cells cultured from the volunteers 7 days post-immunization secreted significant amounts of IgM, IgA and IgG antibody to CPS in vitro. In cell cultures obtained 7 days after immunization of patients, nine of 10 had neither IgM nor IgG antibody response to CPS, and eight lacked anti-CPS IgA. Depletion of T lymphocytes from patients' cell cultures did not promote specific antibody secretion to CPS by B cells. The intense, prolonged antigenaemia with CPS that accompanies cryptococcosis may be responsible for the failure of cured patients to have circulating anti-CPS-secreting cells after immunization.

Adult↗

Symposium on infections in the compromised host. The acquired immunodeficiency syndrome.

The Acquired Immunodeficiency Syndrome (AIDS) is a recently recognized syndrome caused by a newly described retrovirus, Human T-Cell Lymphotropic Virus-III(HTLV-III). A disease that selectively attacks the immune system, manifested by opportunistic infections and unusual neoplasms, AIDS has continued to be confined primarily to several unique at-risk populations. AIDS has evoked unprecedented interest in the medical community, and care of patients with this nearly universally fatal syndrome presents many unique challenges to the health care team.

Acquired Immunodeficiency Syndrome↗