New York University Tuberculosis Exposure Control Plan

Transcription

1 New York University Tuberculosis Exposure Control Plan A. Purpose The purpose of this plan is to establish guidelines and policies for reducing the risk of transmission of TB to employees and volunteers in the University Health Center. The TB Exposure Control Plan is available to all employees at all times. Employees are advised of this availability during orientation and mandatory annual update education/training sessions. B. Background The prevalence of TB is not distributed evenly throughout all segments of the U.S. population. In 1998 there were 1,558 confirmed cases of TB in New York City-more than any other city in the country. Some subgroups or individuals have a higher risk for TB either because they are more likely than others in the general population to have been exposed to and infected with Mycobacterium Tuberculosis [the bacteria which causes TB] or because their infection is more likely to progress to active TB after they have been infected. In some cases, both of these factors may be present. Groups of people known to have a higher prevalence of TB infection include contacts with individuals who have active TB, foreign-born persons from areas of the world with a high prevalence of TB, medically underserved populations, homeless persons, current or former correctional-facility inmates, alcoholics, injecting-drug users, and the elderly. Groups with a higher risk for progression from latent TB infection to active disease include persons who have been infected recently (i.e. within the previous 2 years), children <4 years of age, persons with fibrotic lesions on chest radiographs, and persons with certain medical conditions (i.e. human immunodeficiency virus (HIV) infection, silicosis, gastrectomy or jejuno-ileal bypass, being >10% below ideal body weight, chronic renal failure with renal dialysis, diabetes mellitus, immunosuppression resulting from receipt of highdose corticosteroid or other immunosuppressive therapy, and some malignancies). C. Transmission of TB M. Tuberculosis is carried in airborne particles, or droplet nuclei, that can be generated when individuals who have pulmonary or laryngeal TB sneeze, cough, speak, or sing. The particles are an estimated 1-5 micron in size, and normal air currents can keep them airborne for prolonged time periods and spread them throughout a room or building. Infection occurs when a susceptible person inhales 1

2 droplet nuclei containing M. tuberculosis, and these droplet nuclei traverse the mouth or nasal passages, upper respiratory tract, and bronchi to reach the alveoli of the lungs. Usually within 2-10 weeks after initial infection with M. tuberculosis, the immune response limits further multiplication and spread of the tubercle bacilli, however, some of the bacilli remain dormant and viable for many years. This condition is referred to as latent TB infection. Individuals with latent TB infection usually have positive purified protein derivative (PPD)-tuberculin skin-test results, but they do not have symptoms of active TB, and they are not infectious. D. Individuals Most Likely to Develop Active TB In general, people who become infected with M. tuberculosis have approximately a 10% risk for developing active TB during their lifetimes. This risk is greatest during the first 2 years after infection. Immunocompromised persons have a greater risk for the progression of latent TB infection to active TB disease: HIV infection is the strongest know risk factor for this progression. Persons with latent TB infection who become co-infected with HIV have approximately an 8-10% risk per year of developing active TB. HIV-infected persons who are already severely immunosuppressed and who become newly infected with M. tuberculosis have even greater risk for developing active TB. The probability that a person who is exposed to M. tuberculosis will become infected depends primarily on the concentration of infectious droplet nuclei in the air and the duration of exposure. Characteristics of the TB patient that enhance transmission include the following: a) Disease in the lungs, airways, or larynx b) Presence of acid-fast bacilli (AFB) in the sputum c) Failure of the patient to cover the mouth and nose when coughing/sneezing d) Presence of cavitation on chest radiograph e) Inappropriate or short duration of chemotherapy f) Administration of procedures that can induce coughing or cause aerosolization of M. tuberculosis (e.g. intubation) In addition, the environmental factors that enhance the likelihood of transmission include the following: a) Exposure in relatively small, enclosed spaces b) Inadequate local or general ventilation that results in insufficient dilution and/or removal of infectious droplet nuclei c) Re-circulation of air containing infectious droplet nuclei Characteristics of the individuals exposed to M. tuberculosis that may affect the risk for becoming infected are not as well defined. In general, those who have been infected previously with M. tuberculosis may be less susceptible to subsequent 2

3 infection. However, re-infection can occur among previously infected persons, especially if they are severely immunocompromised. Vaccination with Bacille of Calmette and Geerin (BCG) probably does not affect the risk for infection; rather, it decreases the risk for progressing from latent TB infection to active TB. Finally, although it is well established that HIV infection increases the likelihood of progressing from latent TB infection to active TB, it is unknown whether HIV infection increases the risk for becoming infected if exposed to M. tuberculosis. E. Risk For Exposure Transmission of M. tuberculosis is a recognized risk in health-care facilities. The magnitude of the risk varies considerably by the type of health-care facility, the prevalence of TB in the community, the patient population served, the Health Care Worker s [HCW] occupational group, the area of the health-care facility in which the HCW works, and the effectiveness of TB infection/control interventions. The risk may be higher in areas where patients with TB are provided care before diagnosis and initiation of TB treatment and isolation precautions (e.g. in prehospital care settings) or where diagnostic or treatment procedures that stimulate coughing are performed. Nosocomial transmission of M. tuberculosis has been associated with close contact with persons who have infectious TB and with the performance of certain procedures (e.g. endotracheal intubation and suctioning). Aerosol treatments that induce coughing may also increase the potential for transmission of M. tuberculosis. F. Symptoms of TB The symptoms make take from two to ten weeks to develop for 1% of the people infected, whereas 5-10% may take months, years or even decades to show signs of the disease. The usual symptoms include the following: a) Prolonged cough [more than two weeks] b) Fever, chills and night sweats c) Unexplained fatigue d) Loss of appetite e) Unexplained weight loss G. Treatment and Cure TB can be treated and cured. There are many different treatment regimens. The most commonly used drugs are Isoniazid (INH), Rifampin, and Pyrazinamide. Preceding are the two general types of treatment: 3

4 a) Treatment for active TB Treatment regimen depends on the specifics of the case. In New York City, individuals with active TB are placed on at least 4 drugs for 6-12 months. When multi-drug resistant TB [MDR-TB] is suspected, up to 6 drugs may be used. b) Prophylactic treatment for TB infection An individual who has a positive Mantoux test [PPD], but does not have active TB, may develop active disease at any time in the future. In order to prevent this from happening, the health care provider may recommend that some individuals undergo drug treatment. The usual course of treatment is 1-2 drugs for 6 months. As true of most prescription drugs, anti-tuberculosis drugs occasionally have side effects and may cause other medications to act differently. Information on the side affects can be obtained from the University Health Center [UHC]. H. NYU Tuberculosis Exposure Control Program An effective TB infection control program requires early identification and isolation of persons who have active TB. The primary emphasis of this TB Exposure Control Plan is to achieve these goals by three measures: a) Use of administrative measures to reduce the risk for exposure to individuals who have infectious TB b) Use of engineering controls to prevent the spread and reduce the concentration of infectious droplet nuclei c) Use of personal respiratory protective equipment where there is a risk for exposure to M. tuberculosis Specific steps taken to reduce the risk of transmission of M. tuberculosis will be: 1. Rapid identification of potentially infectious patients Prompt identification of potentially infectious individuals is the cornerstone of the UHC program to protect the employees. All incoming patients with pulmonary signs or symptoms are to be evaluated for pulmonary TB. Any patient suspected of having TB will be given tissues and instructed to cover their mouths when coughing or speaking. 4

5 2. Isolation of potentially infectious patients Patients who are infectious or are suspected of being infectious are to be immediately placed in TB isolation. They are isolated in specially designed infectious disease isolation rooms, which incorporate the following features: a) Negative Pressure: Air will be drawn from the surrounding areas to help ensure that the bacterium doesn t seep out of the rooms and into the hallways. b) 100% Exhaust: None of the air from the isolation rooms is recirculated to other areas of UHC. The air is exhausted away from intake vents, operable windows, animals and people. c) At least 6 Air Changes Per Hour [ACH]: This air exchange will ensure that high concentrations of bacteria do not build up in the rooms. d) HEPA Filters: A high efficiency system will be part of the ventilation system supplying air to the isolation rooms. Proper installation and testing along with meticulous maintenance are critical. The filters must be installed to prevent leakage between filter segments and between the filter bed and its frame. A regularly scheduled maintenance program is required to monitor the HEPA filter for leakage and filter loading. A manometer or other pressure-sensing devices will be installed in the system to provide an accurate and objective way to determine the need to replace the filter as well as the pressure of the room. Maintenance must not contaminate the delivery system or the area served. Special care must be taken in handling the filter, not to jar or drop filter element during or after removal. The filter must be disposed of as contaminated biological waste. Trained personnel wearing appropriate respiratory protection must perform this maintenance. In addition, the filter housing and ducts leading to the housing must be labeled clearly with the words Contaminated Air. 3. Restricted access to patient in TB isolation Patients in TB isolation must remain in their rooms except for testing if it is critical to their treatment. Only direct care providers/deliverers [e.g., Nurses, Building Services, etc.] will be allowed to enter the isolation areas. Patients can be contacted by 5

6 phone for activities such as nutritional counseling and social work consults. 4. Environmental controls for high-risk procedures Sputum inductions and aerosolized pentamidine treatments are not to be performed in the UHC. If the patient is suspected to have active TB, transfer to a hospital more equipped such as NYU Medical Center. 5. Established respirator usage for HCW at UHC Respirators are used to protect personnel from exposure to airborne M.TB. The respirators in use at UHC filter particles the size of droplet nuclei, such that the filtering device will be effective for molecules 1-5 microns in size. A. Mask use indication respiratory devices will be worn whenever there is confirmation that an airborne infectious disease exists. If a patient has obvious droplet expression due to coughing or sneezing, for example, a respirator must be worn for the duration of patient care and treatment after being donned. B. Donning procedure guidelines: 1. The HCW will obtain a respirator in the appropriate size as previously determined by Qualitative fit-testing [QLFT]. 2. Remove the respirator from the packaging, and hold in its flat, folded format. 3. Keep the respirator closed, bend the nose clip around to fit shape of nose, then bend in a slight upward flare. 4. Open the respirator carefully so that there is minimal handling inside the respirator. 5. Pull the lower portion of the headband strap so that it hangs longer than the upper portion of the strap. The upper portion of the strap should be against the nose clip. Remove any twists in the strap. Hook the respirator under the chin and stretch the lower portion of the 6

7 strap over the head. Position the strap around the neck. 6. Pull the portion of the strap that is against the nose clip over the head. Position high on the crown of the head and above the ears. Adjust straps so that there is equal tension on all four straps. 7. Use fingers to shape the nose clip so that the respirator seals over the nose. Ensure that the respirator fits comfortably and seals against the face. 8. Check the fit by placing both hands completely over the respirator and exhale forcefully. A positive pressure should be felt inside the face piece. If air escapes around the nose, re-adjust the nose clip. If air leaks around the edges, adjust the straps to obtain a better fit. If a proper fit is not achieved, Do Not Enter the contaminated area. C. Doffing procedure guidelines: 1. Remove the respirator from the face by using the head strap only. 2. Discard the respirator into the appropriate biomedical waste receptacle if it has been used with a patient with documented respiratory infection, contaminated with blood or OPIM, or been damaged so that the structural integrity is compromised. 3. Wash hands with soap and water or a waterless antiseptic hand cleaner. Hands must be washed at completion of treatment or call and at the first opportunity for cleansing. D. Additional considerations: 1. When a potential infectious respiratory exposure exists, always don a respiratory prior to entering the area surrounding the patient. 2. Ensure hands are clean as possible prior to putting on the respirator. 7

8 3. Ensure that the respirator covers the nose and mouth while performing treatment or services for a patient. 4. Change a respirator if it becomes wet. The respirator is ineffective when moist. 5. Never let a respirator hang around the neck. 6. Before changing a respirator, wash hands. 7. Never remove the respirator while performing treatment or services for the patient. 8. Respirator may be reused if not contaminated by blood, not structurally compromised or not worn around patients documented as having respiratory infection. 9. Never touch the respirator while in use. 10. Do not compromise face seal with beards, facial hair or other conditions that prevent direct contact between the face and the edge of the respirator. 11. All employees who must wear respiratory protection, must be medically evaluated to wear the device. 12. Environmental Services will perform fit testing on all employees that must wear respiratory protection as part of their job. 6. Employee testing for TB All employees are encouraged to have a PPD test for TB done on an annual basis. The test will be paid for by the department and will be performed by the UHC. Following any significant exposure to M. TB, responders will be sent for baseline testing and any follow-up test or treatment as recommended by medical personnel at UHC. Any employee who has a persistent cough [i.e., cough lasting three or more weeks] especially in the presence of other signs or symptoms compatible with active TB [weight loss, night sweats, bloody sputum, anorexia or fever] must be promptly evaluated for TB. No employee may return to work until a diagnosis of TB has been excluded or that individual is on therapy and a determination has been made that the person is non-infectious. 8

9 7. Training for employees All HCW will be trained on the transmission of M. TB, symptoms of TB, types of testing/screening programs, preventive methods and controls, and treatments. Any employee required to wear a respirator will also be trained under NYU Respiratory Protection Program [Policy # 109]. 9