Coronaviruses can cause different pathological processes, from a flu like the common cold to severe acute respiratory failure. The new virus is a strain of the coronavirus family that until then had not been identified in humans (SARS-CoV-2).
The virus is transmitted from person to person when droplets containing viral particles from a patient or an asymptomatic carrier come into contact with mucous membranes in the mouth, nose or eyes of healthy individuals.
Among the main preventive measures for contamination are social isolation, avoiding close or direct contact with other individuals, keeping a social distance between 1.5 m and 2.0 m; avoid touching the face; Wash your hands frequently with soap and water or use an alcohol-based hand rub.
However, during ultrasound examinations, proximity to patients is inevitable, as the physician needs to touch the patient with the transducer to acquire diagnostic images. On the other hand, the safety of doctors, as well as of all health professionals, who cannot be omitted in times of health crisis like this one, must be an absolute priority. Thus, the Brazilian College of Radiology and Image Diagnosis (CBR), in line with other scientific societies, took the initiative to disseminate this document, emphasizing the importance of carrying out the exams with maximum safety.
1) Security starts with proper indication of the exam. Patients should not be exposed to unnecessary risk or occupy health teams with tests that will not add relevant information to the patient's conduct. exams of checkup as well as various examinations of "routine" can be postponed for more opportune times. Only this attitude reduces the risk of contamination for individuals, who will not travel to the services, and allows medical teams to direct their time and effort to care for those who really need it.
2) We encourage studies focused on the patient's complaint or the prescribing physician's diagnostic suspicion, in order to reduce the examination time.
And, finally, individual protection measures that are different from specific scenarios must be implemented.
Scenario 1: ultrasound examination performed on an outpatient without respiratory symptoms
The patient does not need to wear a mask. The use of PPE is not formally recommended for those who perform the ultrasound examination.
Scenario 2: ultrasound examination performed on an outpatient with respiratory symptoms
The patient must wear a mask with minimum filtration equivalent to PFF1, such as surgical masks, from entering the clinic
For the doctor it is indicated:
Use of mask with minimum filtration equivalent to PFF2 - N95;
Disposable gloves, non-sterile;
Long-sleeved waterproof apron, preferably disposable;
Goggles or full face shield.
Scenario 3: ultrasound examination performed on a hospitalized patient WITHOUT respiratory symptoms
The patient does not need to wear a mask. The use of PPE is not formally recommended for those who perform the ultrasound examination.
Scenario 4: ultrasound examination performed on a hospitalized patient WITH respiratory symptoms
The patient must wear a mask with minimum filtration equivalent to PFF1
For the doctor it is indicated:
Use of mask with minimum filtration equivalent to PFF2 - N95;
Disposable gloves, non-sterile;
Long-sleeved waterproof apron, preferably disposable;
Goggles or full face shield.
CLEANING AND ANTISEPSY OF ULTRASOUND EQUIPMENT AND TRANSDUCERS
Another point is cleaning and antisepsis of ultrasound equipment and transducers. The coronavirus is surrounded by a lipid capsid that makes it particularly sensitive to routinely used disinfectants. There is evidence that the virus is effectively inactivated with proper procedures, including the use of common disinfectants in diagnostic clinics and in the hospital environment. The World Health Organization (WHO) suggests that “complete cleaning of surfaces in the environment with water and detergent, followed by the application of disinfectants commonly used at the hospital level” are effective and sufficient procedures to inactivate the new coronavirus.
Ordinary cleaning of the device can be carried out with a cloth soaked in 70% alcohol.
To clean the transducers, disinfection must be effective for any transmissible pathogen, which can be done with several products:
- On the basis of sodium hypochlorite as Dakin's liquid (0.5% active sodium hypochlorite solution);
- Based on quaternary ammonium (QUAT), taking care that the total concentration for use must be less than 0.8%;
- Based on hydrogen peroxide accelerated to a maximum of 0.5%;
- Based on alcohol or alcohol and quaternary ammonia (QUAT). The alcohol content cannot exceed 70%;
It must be taken into account that not all cleaning solutions are compatible with transducers. Therefore, it is recommended to consult the maintenance and cleaning manuals of each device, which contain information on which products can be used to ensure patient safety without damaging the equipment.
CONDUCTOR GEL
To avoid contamination of the ultrasound gel, it is recommended to cap the vial, tube or canister after each use. When applying the gel, do not allow the gel container to touch the patient's skin or the transducer surface.
REPORTING ROOMS
Proper cleaning of benches, keyboards and mice in the report rooms can be done with common products, including 70% alcohol.
For cases without suspected COVID-19, without epidemiology and without respiratory symptoms, the usual disinfection is carried out and the room (and equipment) is released for examinations to be carried out immediately afterwards. After performing tests on patients with high suspicion and/or confirmed COVID-19, it will be necessary to proceed with the disinfection recommended above and the room (and equipment) can be used again afterwards if the patient has all the recommended PPE. If there has been production of aerosols and/or release of any secretion from the patient, after disinfection, wait 2 hours to use it.
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Sources:
- Wilder-Smith A, Chiew CJ, Lee VJ. Can we contain the COVID-19 outbreak with the same measures as for SARS? The Lancet Infectious Disease, Mar 2020, doi: 10.1016/S1473-3099(20)30129-8
- Kampf G, Todt D, Pfaender S, Steinmann E. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. The Journal of Hospital Infection, Mar 2020, 104:246-251.
- Siddharta A, Pfaender S, Vielle NJ, Dijkman R, Friesland M, Becker B, et al. Virucidal Activity of World Health Organization-Recommended Formulations Against Enveloped Viruses, Including Zika, Ebola, and Emerging Coronaviruses. J Infect Dis. 2017; 215: 902–906.
- Ki, HK, Han, SK, Son, JS, and Park, SO Risk of transmission via medical employees and importance of routine infection-prevention policy in a nosocomial outbreak of Middle East respiratory syndrome (MERS): a descriptive analysis from a tertiary care hospital in South Korea. BMC Pulm Med. 2019; 19: 190