Infections associated with use of ultrasound transmission gel: proposed guidelines to minimize risk

Practice 'safe scans': why ultrasound transducer covers should be considered best practice

Single-injection, ultrasound-guided nerve block procedures involve puncturing the skin in close proximity to an ultrasound transducer, creating a potential vector for transmission of microbial organisms when skin flora and blood come into contact with the probe. Practice patterns regarding disinfection of the transducer and the use of barrier protection are inconsistent, ranging from sterile sleeve probe covers to no cover at all. Although sleeve probe covers are easy and straightforward to use and serve to protect patients, providers and medical equipment, their utilisation remains controversial. Standardisation of their use eliminates the impact of improper or haphazard probe disinfection and makes infection control practices consistent and reproducible. This position is shared by multiple societies and authorities on ultrasound and acute care medicine. In this Daring Discourse, we outline the arguments supporting the utilisation of single-use sleeve probe covers to ensure patient safety with respect to vector-borne transmission of microbes during single-injection regional anaesthesia procedures.

Image-Guided Intra-articular Hip Injections and Risk of Infection After Hip Arthroscopy

BACKGROUND

Although intra-articular injections are important in the management of patients who may later undergo hip arthroscopy, conflicting data are available regarding the safety of such injections when administered within 3 months of surgery. Furthermore, despite the increasing use of image-guided intra-articular hip injections, it is unknown whether the type of imaging modality used is associated with infection after hip arthroscopy.

PURPOSE

To assess the risk of infection associated with image-guided intra-articular injections before hip arthroscopy and, secondarily, compare that risk between ultrasound (US) and fluoroscopic (FL) guidance.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This was a retrospective cohort study of patients in a large national insurance database who underwent hip arthroscopy between 2007 and 2017. Patients were required to have continuous enrollment from at least 1 year before to 6 months after hip arthroscopy. Patient age, sex, geographic region, medical history, surgical details, and hip injections were collected. Patients who underwent injection ≤3 months preoperatively and >3 to ≤12 months preoperatively were compared with patients who did not undergo preoperative injection. Bivariate analyses and multivariable logistic regressions were used to assess the association between ipsilateral preoperative hip injection and surgical site infection within 6 months of surgery.

RESULTS

We identified 17,987 patients (36.3% female; mean ± SD age, 37.6 ± 14.0 years) undergoing hip arthroscopy, 2276 (12.7%) of whom had an image-guided hip injection in the year preceding surgery (53.0% FL). Patients who underwent intra-articular injection ≤3 months preoperatively had similar infection rates to patients who did not undergo preoperative injection in the year before surgery for both the FL (0.46% vs 0.46%; P≥ .995) and the US cohorts (0.50% vs 0.46%; P = .76). Results persisted in adjusted analysis (FL ≤3 months: OR, 1.04; 95% CI, 0.32-3.37; P = .94; US ≤3 months: OR, 1.19; 95% CI, 0.36-3.90; P = .78). Similar results were seen for patients undergoing injections >3 to ≤12 months preoperatively.

CONCLUSION

Postoperative infection was rare in patients undergoing intra-articular hip injection ≤3 months before hip arthroscopy and was no more common than in patients not undergoing preoperative injection. Moreover, no differences were seen in infection risk between US and FL guidance. Although intra-articular hip injections should always be administered with careful consideration, these results do not suggest that these injections are uniformly contraindicated in the 3 months preceding hip arthroscopy.

The need for participation in the development and critical review of recommendations for infection control policies involving vascular ultrasound

Recently reported guidelines from the Society of Diagnostic Medical Sonography regarding disinfection of ultrasound probes and infection control policies for ultrasound procedures conflict with accepted clinical norms in vein practices and recommendations from the American Institute for Ultrasound in Medicine. We have provided a review of these conflicting policy recommendations and new proposed practice recommendations and a call for physicians who perform ultrasound-guided procedures to be involved in the process of development and critical review of societal recommendations.

Emergency ward ultrasound: clinical audit on disinfection practices during routine and sterile examinations

Context

In the emergency ward, where the use of ultrasound is common (including for sterile procedures), ward equipment is constantly exposed to high risks of microbiological contamination. There are no clear guidelines for disinfection control practices in emergency departments, and it is not known how emergency ward doctors follow good hygiene practices.

Method

A multi-centre audit was conducted in 16 emergency services from Northern France regional hospitals, in form of a questionnaire. It was proposed to all emergency ward physicians. We excluded questionnaires when physicians mentioned that they did not use ultrasound on a daily basis. The questionnaire was designed using existing hygiene and ultrasound disinfection practices guidelines from varying French medical societies. It included three different clinical scenarios: (a) ultrasound on healthy skin, (b) on injured skin, and (c) ultrasound-guided punctures. All questions were closed-ended, with only one answer corresponding to the guidelines. We then calculated compliance rates for each question, each clinical situation, and an overall compliance rate for all the questions.

Results

104 questionnaires were collected, and 19 were excluded. For the 85 analysed questionnaires, the compliance rates were 60.4% 95% CI [56.4–64.7] for ultrasound on healthy skin, 70.9% 95% CI [66.3–76.1] on injured skin and 69.4% 95% CI [65.1–73.6] for ultrasound-guided punctures. The overall compliance rate for the compliance questions was 66.1% 95% CI [62.8–69.1]. Analysis of the questionnaires revealed severe asepsis errors, misuse of gel, ignorance of infection control practices to be applied in the context of ultrasound-guided puncture and exposure of the probe to body fluids.

Conclusion

This study details areas for quality improvement in the disinfection of emergency ultrasound scanner use. Consequently, we propose a standardized protocol based upon the recommendations used for the questionnaire drafting, with a visual focus on the low compliance points that have been revealed in this audit. This protocol has been distributed to all the medical emergency services audited and included in the emergency resident’s ultrasound learning program.

Survey of ultrasound-guided peripheral intravenous practices: a report of supply usage and variability between clinical roles and departments

BACKGROUND

The purpose of this study was to investigate ultrasound-guided peripheral intravenous (UGPIV) supply usage practices by clinicians working in vascular access, in emergency departments (EDs), or in other roles.

METHODOLOGY

In 2019, a voluntary cross-sectional descriptive survey was conducted via SurveyMonkey. Data collected included demographics, practice-oriented information, procedural activities, and supplies used for UGPIV insertions. Frequency distributions and results of Fisher's exact test and one-way analysis of variance were reported using R v.3.5.2.

RESULTS

A total of 26,649 surveys were distributed with a response rate of 5.5% (n = 1475). Forty-eight percent of respondents (n = 709) indicated that they worked in a vascular access role, 310 (21%) worked in an ED, and 455 (31%) categorized their role as other. Clinically meaningful differences existed in all variables for UGPIV procedures and supplies between departments (P < 0.0001) and in all care settings. Using an investigatorconstructed overall metric of supplies used, important differences were demonstrated between personnel supply use in vascular access roles and other roles (P < 0.0001) and personnel in EDs and other roles (P < 0.0001).

CONCLUSIONS

Use of supplies for UGPIV insertions varies by department. The variability in supply usage for UGPIV insertions revealed by this survey suggests a need for clinical education on guideline application and evaluation of compliance with policies to promote standardization of supplies for UGPIV insertion.

Identification and Analysis of Bacterial Contamination of Ultrasound Transducers and Multiuse Ultrasound Transmission Gel Bottle Tips Before and After the Aseptic Cleansing Technique

OBJECTIVES

To provide a descriptive analysis for species identification of culture and Gram stain results from ultrasound transducers and multiuse ultrasound transmission gel bottle tips in active clinical use and to compare bacterial cultures from ultrasound transducers before and after aseptic cleansing.

METHODS

A prospective blinded descriptive analytic study of 18 distinct clinical care sites within a single primary clinical institution was conducted. Before and after a disinfectant towel cleanse, transducers were pressed against tryptic soy agar contact plates. Plates were deidentified and submitted for blind incubation, Gram staining, and species identification with microsequencing. Results were classified as clinically relevant (CR) or non-clinically relevant. In total, 188 samples were analyzed: 80 from ultrasound transducers before and cleansing, 13 from multiuse gel bottle tips before and after cleansing, and 2 precleansing samples from the data collector's pen and badge.

RESULTS

Fifty-nine precleansing samples (73.8%) grew cultures with CR bacteria, and 21 samples (26.3%) did not. Staphylococcus simulans represented 31.0% of all positive culture samples. Thirteen postcleansing samples (16.3%) grew cultures with CR bacteria, equating to a 78.0% reduction of CR bacterial growth (likelihood ratio, 57.10; P < .001).

CONCLUSIONS

Ultrasound transducers have a notable CR bacterial burden and may serve as potential infective vectors. Aseptic cleansing effectively eliminates most of the bacterial load from ultrasound transducers, but some bacteria persist, presenting a risk of nosocomial infection with ultrasound-guided interventions. These findings support American Institute of Ultrasound in Medicine 2018 guidelines intended to ensure an appropriate level of transducer preparation based on the examination type while emphasizing rational infection control measures to minimize the risk of potential patient harm.

Prevention of pathogen transmission during ultrasound use in the Intensive Care Unit: Recommendations from the College of Intensive Care Medicine Ultrasound Special Interest Group (USIG)

ICU ultrasonography constitutes important part of modern car patient care. Current standards and practice of infection control and prevention are inadequate. This purpose of this document is to adapt and expand the 2017 Australasian Society for Ultrasound in Medicine (ASUM) and the Australasian College for Infection Prevention Control (ACIPC) guidelines on minimum standards for reprocessing/cleaning of ultrasound transducers to the specifics of intensive care medicine and provide advice to the ICU practitioners and health care administrators. It considers the medical, administrative, financial and practical controversies surrounding implementation, and addresses emerging issues of care for patients with confirmed or suspected Corona Virus Disease 2019 (COVID-19).

Medical Ultrasound Disinfection and Hygiene Practices: WFUMB Global Survey Results

As ultrasound technology rapidly evolves and is used more frequently in every area of medical diagnosis and treatment, it may be overlooked as a potential vector in the transmission of a health care-associated infection. A survey on disinfection and hygiene practice in medical ultrasound was disseminated via the World Federation for Ultrasound in Medicine and Biology (WFUMB) to its six member federations and associated ultrasound societies globally. One thousand twenty-nine responses were obtained across a broad range of ultrasound practitioners. A total of 76% of respondents used transducer covers every time to scan open wounds and 71% when blood and bodily fluids were present or for an interventional procedure. Approved high-level disinfectants are not always used, even when blood comes into contact with the transducer or after endocavity scans. Alcohol-based wipes were used by many respondents to clean both external transducers and endocavity transducers. Open-ended responses indicated that a large caseload hindered the time required for cleaning and that access to clear guidelines would be beneficial. Global survey results indicate that some users do not comply with disinfection practice, and there is a gap in knowledge on basic infection prevention and control education within the ultrasound unit. As the infectious status of a patient is not often disclosed prior to an ultrasound examination, training in suitable protocols for the cleaning and disinfection of ultrasound equipment is imperative to mitigate the risk of potential infection.

Infection prevention and control in ultrasound - best practice recommendations from the European Society of Radiology Ultrasound Working Group

OBJECTIVES

The objective of these recommendations is to highlight the importance of infection prevention and control in ultrasound (US), including diagnostic and interventional settings.

METHODS

Review of available publications and discussion within a multidisciplinary group consistent of radiologists and microbiologists, in consultation with European patient and industry representatives.

RECOMMENDATIONS

Good basic hygiene standards are essential. All US equipment must be approved prior to first use, including hand held devices. Any equipment in direct patient contact must be cleaned and disinfected prior to first use and after every examination. Regular deep cleaning of the entire US machine and environment should be undertaken. Faulty transducers should not be used. As outlined in presented flowcharts, low level disinfection is sufficient for standard US on intact skin. For all other minor and major interventional procedures as well as all endo-cavity US, high level disinfection is mandatory. Dedicated transducer covers must be used when transducers are in contact with mucous membranes or body fluids and sterile gel should be used inside and outside covers.

CONCLUSIONS

Good standards of basic hygiene and thorough decontamination of all US equipment as well as appropriate use of US gel and transducer covers are essential to keep patients safe.

MAIN MESSAGES

• Transducers must be cleaned/disinfected before first use and after every examination. • Low level disinfection is sufficient for standard US on intact skin. • High level disinfection is mandatory for endo-cavity US and all interventions. • Dedicated transducer covers must be used for endo-cavity US and all interventions. • Sterile gel should be used for all endo-cavity US and all interventions.

Ultrasound-Guided Peripheral Intravenous Line Placement: A Narrative Review of Evidence-based Best Practices

Peripheral intravenous line placement is a common procedure in emergency medicine. Ultrasound guidance has been demonstrated to improve success rates, as well as decrease complications and pain. This paper provides a narrative review of the literature focusing on best practices and techniques to improve performance with this procedure. We provide an evidence-based discussion of preparation for the procedure, vein and catheter selection, multiple techniques for placement, and line confirmation.

JOURNAL CLUB: Ultrasound-Guided Breast Interventions: Low Incidence of Infectious Complications With Use of an Uncovered Probe

OBJECTIVE

The purpose of this study was to determine the incidence of infectious complications after ultrasound-guided breast interventions performed with an intermediate-level disinfection protocol without an ultrasound probe cover.

MATERIALS AND METHODS

Two independent institutional databases were searched to identify breast infections in patients who underwent ultrasound-guided interventions between January 2005 and July 2013. The departments of radiology and infectious diseases independently maintained these databases. A comprehensive retrospective chart review based on periprocedural antibiotic use and clinical documentation of infection was also performed to reduce the likelihood of missing potential infectious complications.

RESULTS

A total of 12,708 ultrasound-guided breast procedures were performed in the time frame of this study. All potential cases of procedure-related infection were included for subspecialist review in an effort to give the most conservative (highest) estimate of infectious complications. Among these cases, 14 documented cases of possible procedure-related infection were identified, for an overall incidence of 0.11%. All infections were localized skin or soft-tissue infections and adequately treated with a short course of oral antibiotics. No cases of more serious infections or sepsis were found. None of the reported infections required IV antibiotic therapy, percutaneous intervention, surgical intervention, or hospitalization.

CONCLUSION

The incidence of infectious complications after an ultrasound-guided breast intervention without an ultrasound probe cover is extremely low. Physicians can use this information in the development of their disinfection protocols and to provide accurate information in counseling patients during preprocedural consultation.

The ultrasound unit and infection control - Are we on the right track?

Best practice guidelines for the disinfection of ultrasound transducers and infection prevention in ultrasound departments are generally recommended by either government health groups or the ultrasound societies of individual countries. The literature shows a wide variance in not only transducer cleaning methods but basic hygiene practices in the ultrasound workplace. This paper describes results from a UK survey of disinfection of ultrasound transducers and hygiene practice in the workplace. The survey revealed that some ultrasound practitioners did not follow current guidelines with regard to the correct disinfection method of transducers, cords or ultrasound machine keyboards. Furthermore, the survey exposed the lack of training from the product manufacturers on how to use the disinfection product appropriately. These inconsistencies may be responsible for compliance issues and highlight the need for an awareness campaign and a unified approach to infection control by ultrasound practitioners.

Infection prevention and ultrasound probe decontamination practices in Europe: a survey of the European Society of Radiology

OBJECTIVES

Although ultrasound (US) is considered one of the safest imaging modalities, concerns have been raised regarding potential infection transmission risks through US procedures. A survey was undertaken by the European Society of Radiology (ESR) to establish infection prevention and control measures in US and to highlight the importance of good medical practice.

METHODS

An online survey was sent to all 22,000 full ESR members.

RESULTS

The response rate of completed surveys was 4.3 % (946 practitioners, 97 % of which were radiologists, mostly working in larger hospital settings). Among respondents, 29 %, 11 % and 6 % did not disinfect the US probe after every patient when performing standard surface US, endo-cavity US and interventional procedures, respectively. Eleven percent did not always use probe covers for endo-cavity US; for interventional procedures, the proportion was 23 %. A minority used sterile gel sachets in direct patient contact for endo-cavity scans (30 %), and 77.5 % used sterile gel for interventional procedures.

CONCLUSIONS

The survey results highlight a wide range of practices throughout Europe and the need to raise awareness amongst practitioners regarding the importance of infection prevention and control measures. The development of European recommendations encompassing all US examinations, together with education is a priority.

MAIN MESSAGES

• Transmission of infection through ultrasound procedures is possible. • There is a wide range of ultrasound probe decontamination practices in Europe. • Not all practitioners use probe covers for endo-cavity or interventional ultrasound. • Not all practitioners use sterile gel for internal and invasive procedures. • Currently there are no European recommendations encompassing all US examinations.

Prolonged postprocedural outbreak of Mycobacterium massiliense infections associated with ultrasound transmission gel

Postprocedural infections by Mycobacterium abscessus complex are increasing worldwide, and the source and route of transmission are infrequently identified. Here the extension of a previous clustering of paediatric patients with surgical site infections due to a single strain of the subspecies M. massiliense is reported. The investigation was conducted at a 2200-bed teaching hospital in Taiwan and included microbial surveillance of the environment (water, air, equipment and supplies) and a case-control study. We performed molecular identification and typing of the isolates by a trilocus sequencing scheme, confirmed by multilocus sequencing typing and pulsed-field gel electrophoresis. We investigated 40 patients who developed postprocedure soft tissue or bloodstream infections by M. massiliense (TPE101) during a 3-year period. Thirty-eight patients were identified at hospital A, and one newborn and her mother were identified at hospital B (185 km from hospital A). A case-control study identified the association of invasive procedures (adjusted odds ratio, 9.13) and ultrasonography (adjusted odds ratio, 2.97) (both p <0.05) with acquiring the outbreak strain. Isolates from the cases and unopened bottles of ultrasound transmission gel were all of strain ST48 and indistinguishable or closely related by pulsed-field gel electrophoresis. After replacement of contaminated gel, no new cases were detected during 18 months' follow-up. This investigation identified the use of contaminated gel as the common source causing an outbreak on a larger scale than had been recognized. Our findings halted production by the manufacturer and prompted revision of hospital guidelines.

Investigation of current infection-control practices for ultrasound coupling gel: a survey, microbiological analysis, and examination of practice patterns

BACKGROUND AND OBJECTIVES

Ultrasound coupling gel may serve as a vector for the spread of bacteria and has been the causative agent for significant health care-associated infections. The purpose of this study was to document existing infection-control procedures and level of contamination present within nonsterile ultrasound gel from several clinical departments at a single institution. A second purpose was to examine the effectiveness of clinician education and manufacturer-based ultrasound additives on ultrasound gel contamination and in vitro bacterial proliferation, respectively.

METHODS

Compliance with Health Canada recommended infection-control policies were determined by survey. Contamination of in-use ultrasound gel bottles was determined by inspecting cultures after 72 hours of incubation. After infection-control education, a 28-day interval assessment was used to examine contamination rates in newly provided ultrasound gel. The ability of ultrasound gel containing parabens to prevent bacterial growth was examined in cultures grown with and without ultrasound gel.

RESULTS

Practitioners were not compliant with Health Canada recommendations, but the baseline ultrasound gel contamination rate within these departments was only 2.5%. Education in infection control did not improve the contamination rate over 28 days. Contamination was discovered in ultrasound gel supplied directly from the manufacturer. Ultrasound gel suppressed but did not prevent bacterial growth in a species- and time-specific manner.

CONCLUSIONS

The source of contamination for in-use ultrasound gel may be of manufacturer or human origin. Because additives to the ultrasound gel are not bactericidal, sterile ultrasound gel should be used for invasive and high-risk cases, and improving infection-control policies is warranted.

An outbreak of Pseudomonas aeruginosa respiratory tract infections associated with intrinsically contaminated ultrasound transmission gel

We describe an outbreak of Pseudomonas aeruginosa respiratory tract infections related to intrinsically contaminated ultrasound gel used for intraoperative transesophageal echocardiograms in cardiovascular surgery patients. This investigation led to a product safety alert by the Food and Drug Administration and the development of guidelines for appropriate use of ultrasound gel.