Thyge L. Nielsen

Incidence and risk factors of occupational blood exposure: A nation-wide survey among Danish doctors

Occupational blood exposures involves a risk of transmission of serious infections. We performed a nation-wide survey, to describe the incidence and risk factors of percutaneous (PCE) and mucocutaneous (MCE) blood exposures among hospital employed doctors in Denmark. Of 9,374 questionnaires, 6,256 (67%) were returned and 6,005 were eligible for analysis. The highest risk per person-risk-year (pry) was found in General surgery, Neurosurgery, Obstetrics-Gynaecology and Orthopaedic surgery (6.2--8.5 PCE/pry and 7.3--8.8 MCE/pry). The second risk group was Anaesthesiology and Oto-rhino-laryngology (2.6--3.1 PCE/pry and 6.0--6.9 MCE/pry). Finally Pathology, Internal medicine, Radiology and Paediatrics had a considerable risk (0.8--1.3 PCE/pry and 1.3--2.9 MCE/pry). Potential risk factors were examined by Poisson regression. Employment as senior as compared to junior doctor was associated with a higher risk of PCE (RR 2.2) and MCE (RR up to 2.7 depending on experience) among surgeons and an increased risk of PCE in anaesthetists (RR 1.7). In contrast, senior physicians in Internal medicine, Radiology and Paediatrics had a several fold lower risk of PCE (RR 0.6) and MCE (RR 0.6 in males, 0.3 in females). Only 35% adhered to the basic principles of universal precautions (UP) and non-compliance was associated with a considerably increased risk of both MCE and PCE, especially in non-surgical specialties. In conclusion, we found an unacceptably high incidence of occupational blood exposures among Danish doctors. Non-compliance with UP was associated with an increased risk of exposure and efforts to improve compliance with UP as well as implementation and evaluation of other preventive measures are needed.

Percutaneous blood exposure among Danish doctors : Exposure mechanisms and strategies for prevention

The objective of this study was to describe the mechanisms of percutaneous blood exposure (PCE) among doctors and discuss rational strategies for prevention. Data were obtained as part of a nation-wide questionnaire survey of occupational blood exposure among hospital employed doctors in Denmark. The doctors were asked to describe their most recent PCE, if any, within the previous 3 months. Detailed information on the instruments, procedures, circumstances and mechanisms that caused the PCE was obtained. Of 9375 doctors, 6256 (67%) responded, and 6005 questionnaires were eligible for analysis. Of 971 described PCE the majority were caused by suture needles (n = 483), IV-catheter-stylets (n = 94), injection needles (n = 75), phlebotomy needles (n = 53), scalpels (n = 45), arterial blood sample needles (n = 41) and bone fragments (n = 23). Inattentiveness was the most common cause, contributing to 30.5% of all PCE. Use of fingers rather than instruments was a major cause of injury in surgical specialties and was a contributing cause of 36.9% PCE on suture needles. Common contributing causes when fingers were used (n = 199) were poor space in (30.2%) or view of (18.6%) the operation field. It was often argued that instruments were not practical to use or might harm the tissue. Of 689 PCE in surgical specialties, 17.4% were inflicted by colleagues. Up to 53.3% of PCE on hollow-bore needles could be attributed to unsafe routines like recapping only, but other mechanisms like sudden patient movements and ‘acute situation’ were common, especially in the case of PCE on iv-catheter-stylets. It is concluded that the exposure mechanisms of PCE reflect both unsafe routines, difficult working conditions and unsafe devices. Education in safer working routines are needed in all specialties. Introduction of safer devices should have a high priority in surgical specialties, and should be considered in non-surgical specialties too.

The Seroprevalence of Hepatitis B and C in Hospitalized Danish Patients

Health care workers are at risk of acquiring blood-borne infections. To assess the risk of exposure to hepatitis B or C in the case of occupational blood exposure, we determined the seroprevalence of these infections in 466 patients admitted to a Copenhagen university hospital. Serological markers for hepatitis B or C were detected in 56 patients (12.0%). The seroprevalence of HBsAg and anti-HCV was 0.9% and 1.5% respectively. HCV RNA, indicating ongoing hepatitis C, was found in five of seven anti-HCV-positive patients by polymerase chain reaction. The serological findings had not previously been diagnosed in 4 of 10 potentially infectious patients and only 6 of 10 patients belonged to high-risk groups. In conclusion, health care workers should be aware of the potential the occupational risk of hepatitis B and C even in a low-prevalence country like Denmark. Management of health care workers after blood exposure should include serological testing for both hepatitis B and C. Strict adherence to universal precautions is recommended and vaccination against hepatitis B should be encouraged.

Occupational Blood Exposure among Health Care Workers: I. Frequency and Reporting

The frequency and reporting rate concerning occupational blood exposure were investigated among former and currently employed medical staff at a Department of Infectious Diseases (DID) having a high prevalence of HIV-positive patients. Subjects were asked to complete an anonymous questionnaire describing occupational percutaneous exposure (PCE) and mucocutaneous exposure (MCE) to blood, experienced during their employment at the DID. 135 out of 168 (80%) subjects responded. 45 subjects described 37 incidents of PCE and 15 of MCE. 44 of the exposures (85%) involved HIV-positive blood and 6 (11.5%) involved blood from a patient with hepatitis B. Annual incidence rates of PCE and MCE were: for A) interns and residents, 0.51 PCE/year and 0.17 MCE/year; B) for senior residents and senior physicians, 0.13 PCE/year and 0.21 MCE/year; C) for registered nurses, 0.11 PCE/year and 0.03 MCE/year; D) for auxiliary nurses, 0.09 PCE/year and 0.11 MCE/year. 35% of PCE and 87% of MCE were not reported to the security representative, the major reason being that the subject felt it to be unnecessary. We conclude that medical employment, especially as interns and residents at clinics for infectious diseases, carries a real and serious risk of contracting infectious diseases due to occupational exposure to blood. The importance of reporting needs to be emphasized.

Randomized Study of Sulfamethoxazole-trimethoprim versus Aerosolized Pentamidine for Secondary Prophylaxis of Pneumocystis carinii Pneumonia in Patients with AIDS

In a prospective, randomized open-label trial, the efficacy of sulfamethoxazole-trimethoprim (SMX-TMP) 400/80 mg b.i.d. was compared with the efficacy of aerosolized pentamidine (AP) 60 mg every 2nd week as secondary prophylaxis (SP) against recurrence of Pneumocystis carinii pneumonia (PCP) in AIDS patients. 94 patients participated in the study, 47 in each group. The patients were observed for a mean period of 17.2 months. PCP recurred in the AP group in 8 cases, while 1 relapse occurred in the SMX-TMP group. The one-year cumulative relapse rate was 9.0% (95% CI 0-19%) in the AP group compared with 2.4% (95% CI 0-8%) in the SMX-TMP group (p < 0.05). The odds ratio was 4.2 (95% CI 0.5-39.8) in favour of SMX-TMP. Furthermore, we found a tendency towards a protective effect against toxoplasmosis in the SMX-TMP group, though there was no difference in survival between the two groups. There was no statistical difference in frequency of crossover from one therapy form to the other. Based on these data we recommend SMX-TMP for secondary PCP prophylaxis.

Occupational blood exposure among health care workers: II. Exposure mechanisms and universal precautions.

We investigated mechanisms of mucocutaneous exposure (MCE) and percutaneous exposure (PCE) to blood, and compliance with protective barriers among all former and presently employed medical staff at a Danish Department of Infectious Diseases. All subjects were asked to complete an anonymous questionnaire. 135 out of 168 (80%) subjects responded. 37 incidents of PCE and 15 MCE were described. More than 50% of PCE had occurred without obvious explanation during medical procedures, or were caused by unexpected patient movement, while only 1 PCE was caused by recapping. 35% of PCE occurred during drawing of venous blood samples. Compliance with usage of gloves was high (70-100%), depending on the procedure, and 72% of the subjects claimed to have sufficient knowledge of the risk of blood exposure and how to prevent it. Yet 11 (73%) out of 15 MCE might have been prevented by appropriate use of protective barriers. To further reduce the frequency of blood exposure, the development of safer instruments and unceasing education in safer technique and use of protective barriers are of major importance.

Prevention of pneumocystis carinii pneumonia relapse by aerosolised pentamidine, 60 mg biweekly, using an acorn system 22 nebuliser

The effectiveness of biweekly administration of 60 mg aerosolised pentamidine (AP) as secondary prophylaxis against relapse of Pneumocystis carinii pneumonia (PCP) was investigated in 45 male AIDS patients. The nebuliser used was an Acorn System 22. In total the patients received AP for a mean period of 13.8 months (3.4-28.8). Six episodes of recurrent PCP were recorded. Relapse per full year of treatment on AP was 12%.

The Outcome of Pneumocystis carinii Pneumonia in Danish Patients with AIDS

A total of 100 consecutive patients with AIDS were evaluated for efficacy and safety of treatment and secondary prophylaxis directed against Pneumocystis carinii pneumonia (PCP). 89 episodes of PCP were recorded in 75 patients. 63 of the 75 patients (84%) with a first episode of PCP were discharged. Of 72 patients with a first episode of PCP who were initially treated with trimethoprim-sulfamethoxazole. 76% completed therapy successfully. Side effects were common, but generally mild and tolerated during continued treatment. 7/11 patients (64%) with a first episode of PCP who required mechanical ventilation were discharged. Long term prognosis for these patients was not worse than for patients who did not require mechanical ventilation. Relapse of PCP occurred in 3/50 patients (6%) during secondary prophylaxis, 160 mg trimethoprim and 800 mg sulfamethoxazole (TMP-SMZ) every 24 h, compared to 11/16 (69%) patients who were not receiving prophylaxis (p less than 0.00001). No patients discontinued prophylaxis because of side effects. It is concluded that for most patients with AIDS and PCP, treatment and secondary prophylaxis with TMP-SMZ is safe and effective.

CD4 lymphocyte counts and serum p24 antigen of no diagnostic value in monitoring HIV-infected patients with pulmonary symptoms.

The diagnostic value of the CD4 cell counts and the HIV p24 antigen were evaluated in a consecutive series of 105 HIV-infected patients experiencing 128 episodes of pulmonary symptoms which required bronchoscopy. One-third of patients with opportunistic infection (OI) had CD4 counts greater than 0.200 x 10(9)/l, and 60% of patients without OI had CD4 counts less than 0.200 x 10(9)/l; 47 and 42% of patients with and without OI, respectively, had detectable p24 antigen in serum. Only 36% of the patients with OI presented the combination of CD4 cells less than 0.200 x 10(9)/l and p24 in serum. In conclusion, the CD4 cell counts and the presence of p24 antigen in serum had a very limited predictive value for the presence of OI in HIV-infected patients with pulmonary symptoms.

Cardiac arrest during treatment of pneumocystis carinii pneumonia with intravenous pentamidine isethionate.

A 27-year-old man, HIV-positive for 4 years, developed ventricular fibrillation and cardiac arrest during treatment of Pneumocystis carinii pneumonia with intravenous pentamidine isethionate. The dosage was 4 mg/kg/day for 18 days. Nephrotoxicity occurred and raised serum potassium. The plasma concentration of pentamidine was 580 nmol/l. Careful monitoring of renal and cardiac functions is recommended during intravenous therapy with pentamidine isethionate.