Advancing infection control in Australasian medical ultrasound practice

Abstract

Introduction/Aims

Australasia is witnessing a rapidly increasing use of diagnostic medical ultrasound in clinical practice with industry statistics giving a conservative estimate of ten million scans performed annually in Australia and New Zealand. Ultrasound practice has broadened from its traditional use in radiology, obstetrics and gynaecology, vascular and cardiology specialties to embrace emergency medicine, rheumatology, midwifery, physiotherapy, paramedics and other point of care practice. With this expansion of practice comes an increase in the potential risk for ultrasound transmitted bacterial or viral infection due to suboptimal cleaning habits of transducers, cords and keyboards.

Results/Conclusion

This study describes results of an Australasian survey on the disinfection and hygiene practice in medical ultrasound. Results highlighted a significant need for updated guidelines and education on infection prevention and control in medical ultrasound.

Introduction

With the expanding use of diagnostic ultrasound in medical practice in Australia, there is an increased risk of healthcare‐associated infections (HAIs) being transmitted between patient, operator and the ultrasound equipment. Effective infection control within the ultrasound practice has become an important and serious issue that needs to be addressed.

Over 200,000 HAIs are reported annually in Australia, and they are one of the major causes of morbidity and mortality in our healthcare facilities.1 In an attempt to address this problem, the National Health and Medical Research Council (NHMRC) developed a risk‐management framework for human and system factors associated with the transmission of infection. This framework includes NHMRC Ref:CD33 Australian Guidelines for the Prevention and Control of Infection in Healthcare 2010.1 Standards Australia, a peak non‐governmental standards body, recommends ‘AS/NZS 4187‐2014’ be followed for disinfecting and sterilising reusable medical equipment, and the Therapeutic Goods Administration (TGA) ‘54B’ regulates the types of disinfectants suitable for high‐, medium‐ and low‐level medical use. These three bodies set the basic guidelines for infection control applicable to the practice of diagnostic ultrasound in Australia.2, 3

A literature search has resulted in numerous protocols and recommendations that aim to prevent cross contamination and infection and improve the safety of patients undergoing ultrasound examination.4, 5, 6, 7 The majority of these protocols had no input from relevant infection prevention and control (IPC) advisors.

Recent Australian research showed the prevalence of bacterial contamination within the ultrasound unit with potentially pathogenic species including Acinetobacter lwoffii and Staphylococcus haemolyticus.8, 9 These findings suggest that current disinfection guidelines need to be revised with a greater focus on IPC within the ultrasound unit. The works join an increasing list of literature where the conclusions show a risk of viral or bacterial infection being transmitted to the patient during an ultrasound examination due to transducer contamination.10, 11, 12, 13, 14, 15, 16, 17, 18 There are however limited studies on the risk of contamination of the actual ultrasound machine and workstations.8, 19, 20

A short pilot survey conducted by the Australasian Society for Ultrasound in Medicine (ASUM) indicated that there are operators who do not comply with ultrasound disinfection guidelines.21 In an attempt to further understand the current ultrasound disinfection methods and hygiene practices, a comprehensive survey was designed and promoted by the World Federation of Ultrasound in Medicine (WFUMB) to all of its six member federations and societies. This article describes the results obtained from Australia and New Zealand.

Methods

A total of 28 questions on ‘Disinfection and Hygiene practice in Medical Ultrasound’ were designed using an online survey tool (Survey Monkey). This was sent to members from ASUM, Australasian Sonographers Association and other societies that utilise ultrasound in January 2016. The survey was divided into three main components. The first part of the survey explored the background demographics of the respondents such as qualification, current employment status, place of work (private or public) and number of scans performed per day. The second part of the survey questioned the disinfection practices of the respondents including methods of disinfecting external and intracavity transducers, cleaning the ultrasound machine keyboard and cord and the use of sterile gel, gloves and probe covers. The final part of the survey explored the training and support of respondents. There were also options to include comments in a text box.

Results

A total of 395 respondents were from Australia and New Zealand (data as of 2 November 2016) with sonographers representing the majority of respondents (Table 1).

Table 1.

Training background of respondents from Australia and New Zealand

Training background	Responses % (number)
Radiologist	1.03 (4)
Obstetrician/Gynaecologist	2.05 (8)
Vascular/Cardiologist	0.26 (1)
Emergency Medicine Specialist	2.05 (8)
Medical practitioner specialising in ultrasound	0.51 (2)
Medical practitioner using ultrasound occasionally	1.03 (4)
Sonographer/ultrasound technician	84.10 (328)
Formal qualification in ultrasound	4.87 (19)
Other (please specify)a	4.10 (16)
Total	390b

^aresponses included: Trainee sonographer, radiographer, breast sonographer and nurse practitioner.

^bOf a total of 390 respondents, five skipped question.

A total of 60% of respondents worked in a private practice and the remainder from public hospitals. When assessing workload, 36% of respondents performed between 12 and 15 scans per day, followed by 22% who performed between 16 and 19 scans per day (Table 2).

Table 2.

Number of scans performed per day from Australian and New Zealand respondents

Number of scans performed per day	Responses % (number)
Nil	0.67 (3)
<3	3.04 (12)
4–7	7.34 (29)
8–11	22.03 (87)
12–15	36.71 (145)
16–19	22.53 (89)
More than 20	7.59 (30)
Total	395

A number of statements were used to assess the respondent's use of approved and non‐approved agents for the disinfection of ultrasound transducers (Table 3). With regard to the use of non‐approved agents such as Milton's solution, a total of 12% (36 of 293 respondents) still use the product for disinfecting external transducers and 16% (44 of 270 respondents) use the product for disinfecting intracavity transducers. Furthermore, 3.6% (12 of 334 respondents) do not use an approved high‐level disinfectant for intracavity scans every time. When the ultrasound transducer comes into contact with blood, over 13% (50 of 361 respondents) do not use an approved high‐level disinfectant to clean the transducer every time.

Table 3.

Statements regarding the use of approved and non‐approved agents for disinfection of ultrasound probes

Statement	Never (0%)a	Rarely (1–19%)a	Occasionally (20–39%)a	Sometimes (40–59%)a	Frequently (60–79%)a	Usually (80–99%)a	Every time (100%)a	Total number of responses (out of 395)
I disinfect external transducers with Milton solution (or equivalent)	87.71% (257)	5.12% (15)	2.73% (8)	2.05% (6)	0.68% (2)	0.68% (2)	1.02% (3)	293
I disinfect intracavity transducers with Milton solution (or equivalent)	83.70% (226)	6.30% (17)	2.22% (6)	0.74% (2)	1.11% (3)	0.37% (1)	5.56% (15)	270
At the end of every intracavity scan, I disinfect the transducer with an approved high‐level disinfectant	1.2% (4)	0.3% (1)	0.3% (1)	0.0% (0)	0.3% (1)	1.50% (5)	96.41% (322)	334
When blood comes into direct contact with any transducer, I disinfect with an approved high‐level disinfectant	2.22% (8)	1.39% (5)	0.55% (2)	1.39% (5)	1.66% (6)	6.65% (24)	86.15% (311)	361

^aValues are expressed as responses % (number of responses).

With regard to cleaning the ultrasound unit after an examination, respondents were more likely to clean the ultrasound machine cord instead of the keyboard after each patient. A proportion of respondents never cleaned the keyboard (7.6%) or the cord (5.6%; Table 4).

Table 4.

Frequency of cleaning the ultrasound machine keyboard and cords

Cleaning Frequency	Machine keyboard Response % (number)	Machine cord Response % (number)
After each patient	10.97 (43)	35.37 (139)
Once a day	56.12 (220)	31.81 (125)
Once a week	20.66 (81)	15.52 (61)
Once a month	7.91 (31)	8.14 (32)
Once every 6 months	2.04 (3)	3.56 (14)
Never	7.57 (8)	5.60 (22)
Total	392a	393b

^aOf a total of 395 respondents, three skipped question.

^bOf a total of 395 respondents, two skipped question.

A number of statements were used to assess the training and support provided within the respondent's ultrasound department (Table 5). A total of 61% of respondents undertook a workplace disinfection induction and 54% receive support from infection control specialists. When purchasing an ultrasound machine, 52% of respondents did not receive training from the machine manufacturer on how to clean the appropriate transducer. When purchasing a disinfection product, 29% of respondents did not receive any training from the product manufacturer on how to use the product.

Table 5.

Statements regarding support and training

Statement	Yes Response % (number)	No Response % (number)	Total number of responses (out of 395)
In your department, do you undertake a workplace disinfection induction?	61.70 (240)	38.30 (149)	389
In your department, do you receive any support or training from infection control specialists?	54.87 (214)	45.13 (176)	390
When purchasing a new ultrasound machine/transducer, do you receive any training from the machine manufacturer on how to clean the appropriate transducer?	47.76 (181)	52.24 (198)	379
When purchasing a new product to clean the transducer, do you receive any training from the product manufacturer on how to use the appropriate product?	70.48 (265)	29.52 (111)	376

Many respondents filled comments into the open‐ended boxes requesting for further training, support and clearer guidelines pertaining to disinfection of ultrasound transducers.

Conclusion

Ultrasound training courses in Australia are amongst the best in the world, with a large percentage of course time spent on the correct use of the ultrasound technology. Unfortunately, the subject of IPC may not be adequately covered in these training programmes. Information on the infectious status of a patient may not be accessible to the ultrasound operator at the time of the examination. This lapse of disclosure increases the risk of infection transmission to the operator and to subsequent patients as correct disinfection procedures of the ultrasound equipment may have been neglected. Hence, it would be prudent for all ultrasound users to not only undertake a basic IPC training programme but also to understand the infection control guidelines set by their national governing bodies or societies.

Realising the need for updated infection control guidelines for ultrasound practice, ASUM in collaboration with the Australasian College of Infection Prevention and Control (ACIPC) has developed the ‘Guidelines for Reprocessing Ultrasound Transducers’.22 Once implemented, these recommendations, if correctly followed, should limit the spread of HAIs in the ultrasound unit.