Droplet precautions are measures that have been developed to limit the airborne spread of microorganisms in droplets that are larger than 5 microns in diameter (a micron is 10−6 of a meter or one millionth of a meter). These droplets are typically expelled into the air by coughing, sneezing, and even by talking.
Droplets that are smaller in diameter are considered to be aerosols and, since they may travel greater distances, are governed by the airborne precautions category of infection control.
The droplet precautions developed by agencies including the U.S. Centers for Disease Control and Prevention (CDC) and issued as guidelines in 1996 are designed to limit the spread of droplets with the cells of the eyes, nose, and mouth. This is important in a hospital, where droplets expelled by someone with an infection could spread the disease to someone else.
Because the droplets are relatively large, they are heavier and tend not to travel as far (less than three feet) as aerosolized microorganisms. Thus, droplet precautions are designed to prevent the movement of microorganisms from one person to someone else who is within about three feet or less.
Viral diseases for which droplet precautions are necessary include chickenpox, influenza, measles, German measles, mumps, smallpox, and severe acute respiratory syndrome (SARS). Bacterial diseases requiring these precautions include whooping cough, a form of meningitis, psittacosis, Legionnaire's disease, diphtheria, and pneumonia. Finally, the inhalation of fungi-laden droplets can cause allergic alveolitis, aspergillosis, histoplasmosis, and coccidiodomycosis.
Droplet precautions are a necessary part of a hospital's infection control strategy. Without such precautions, the airborne spread of disease would occur more frequently. These precautions can be initiated by the attending health care providers, including the physician and the nursing staff, and by the person in charge of infection control. The latter usually has the final say in whether precautions will be observed or not. The use of droplet precautions must be documented in the patient records. This information that can be important in tracing the effectiveness of the precautions in controlling the infection and minimizing its spread.
WORDS TO KNOW
AEROSOL: Particles of liquid or solid dispersed as a suspension in gas.
CONTACT PRECAUTIONS: Contact precautions are actions developed to minimize the transfer of microorganisms by direct physical contact and indirectly by touching a contaminated surface.
DROPLETS: A drop of water or other fluid that is less than 5 microns (a millionth of a meter) in diameter.
Placing the infected patient in a separate room can be sufficient to prevent the spread of droplet-borne microbes. Specially ventilated rooms are not required, nor does the door to the room need to be closed. If a separate room is not available, then the infected patient should be housed with a patient who has an infection with the same microorganism and no other condition. That way, if the microbe is transferred between the patients via droplets, it will have a negligible influence on either patient's health. The patients's beds should be physically separated by a minimum of three feet, and visitors should not be allowed within three feet of the patient they are visiting.
A face mask should be worn when either a health care provider or a visitor comes in close contact with the infected patient. Standard masks, similar to the type worn by carpenters to prevent inhalation of dust and other construction debris, are sufficient. Ideally, the mask should be put on as a person enters the patient's room and should be discarded in a hazardous waste container as the person is leaving.
The infected patient should be moved to other areas of the hospital only as is necessary, and should wear a mask during the transport. In addition, any visitors who have not been previously exposed to the infection that the patient has should not be allowed to enter the patient's room. Droplet precautions are often used in conjunction with contact precautions (infection control procedures designed to minimize the spread of disease by direct or indirect contact) in hospitals.
Droplet precautions can be discontinued when a patient's symptoms, such as coughing, have disappeared.
Droplet precautions are intended to benefit the patient and medical personnel and to control and contain a disease outbreak. However, these measures come not only with a financial cost, but with a psychic cost when images of masked patients, cargivers, and even members of the general public are given wide circulation by the media. A recent example occurred in Toronto, Canada, in March 2003, when several hundred people were affected by a SARS outbreak. Unsettling images of masked citizens in China (where the SARS outbreak originated) engaging in everyday activities, and of masked healthcare workers in Toronto were shown around the world. The precautions observed during the Toronto outbreak were subsequently cited as key in containing the infection. Yet, this success came at a cost. A report released in 2005 documented that infection control procedures, including droplet precautions, lost revenue, and additional labor costs, for one of the several affected Toronto hospitals totaled $12 million.
Drexler, Madeline. Secret Agents: The Menace of Emerging Infections. New York: Penguin, 2003.
Tierno, Philip M. The Secret Life of Germs: What They Are, Why We Need Them, and How We Can Protect Ourselves Against Them. New York: Atria, 2004.
Wenzel, Richard P. Prevention and Control of Nosocomial Infections. New York: Lippincott Williams & Wilkins, 2002.
Centers for Disease Control and Prevention. “Droplet Precautions.” April 1, 2005. <http://www.cdc.gov/ncidod/dhqp/gl_isolation_droplet.html> (accessed April 3, 2007).