Disinfection of Ultrasound Transducers Used for Percutaneous Procedures: Intersocietal Position Statement

Cost of sterility: probe covers should not be mandated for single-shot peripheral nerve blocks

Ultrasound guidance has become ubiquitous with regional anesthesia, but little consistency exists on necessary ultrasound probe hygiene and sterility barriers. Fear of possible infection has led to calls for universal use of sterile ultrasound probe covers. Available data seems to suggest that single-shot peripheral nerve blocks have a low infectious risk. The widespread use of single-use disposable probe covers would carry an associated cost, increased environmental impact, and little evidence to suggest that they are effective at preventing infection if proper technique is used. While various parties have labeled single-shot nerve blocks as a sterile procedure, in practice, it is a clean technique. In this article, we argue that mandating the use of probe covers is unnecessary and that it should be left to the anesthesiologist to determine what type of anti-infection equipment is necessary for single-shot nerve blocks based on their practice situation and expertize.

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.

Best Practices for Point of Care Ultrasound: An Interdisciplinary Expert Consensus

Despite the growing use of point of care ultrasound (POCUS) in contemporary medical practice and the existence of clinical guidelines addressing its specific applications, there remains a lack of standardization and agreement on optimal practices for several areas of POCUS use. The Society of Point of Care Ultrasound (SPOCUS) formed a working group in 2022 to establish a set of recommended best practices for POCUS, applicable to clinicians regardless of their training, specialty, resource setting, or scope of practice. Using a three-round modified Delphi process, a multi-disciplinary panel of 22 POCUS experts based in the United States reached consensus on 57 statements in domains including: (1) The definition and clinical role of POCUS; (2) Training pathways; (3) Credentialing; (4) Cleaning and maintenance of POCUS devices; (5) Consent and education; (6) Security, storage, and sharing of POCUS studies; (7) Uploading, archiving, and reviewing POCUS studies; and (8) Documenting POCUS studies. The consensus statements are provided here. While not intended to establish a standard of care or supersede more targeted guidelines, this document may serve as a useful baseline to guide clinicians, leaders, and systems considering initiation or enhancement of POCUS programs.

Comparison of Low-Level to High-Level Disinfection in Eliminating Microorganisms From Ultrasound Transducers Used on Skin: A Noninferiority Randomized Controlled Trial

INTRODUCTION

There is a lack of international consensus as to whether high- or low-level disinfection (HLD or LLD) is required for ultrasound (US) transducers used during percutaneous procedures. This study compared the effectiveness of LLD to HLD on US transducers contaminated with microorganisms from skin.

METHODS

Two identical linear US transducers repeatedly underwent either LLD or HLD during the study. Randomization determined which of these transducers was applied to left and right forearms of each participant. Swabs taken from transducers before and after reprocessing were plated then incubated for 4-5 days, after which colony forming units (CFU) were counted and identified. The primary hypothesis was the difference in the proportion of US transducers having no CFUs remaining after LLD and HLD would be less than or equal to the noninferiority margin of -5%.

RESULTS

Of the 654 recruited participants 73% (n = 478) had microbial growth from both transducers applied to their left and right forearms before reprocessing. These were included in the paired noninferiority statistical analysis where, after disinfection, all CFUs were eliminated in 100% (95% CI: 99.4-100.0%) of HLD transducer samples (n = 478) and 99.0% (95% CI: 97.6-99.7%) of LLD transducer samples (n = 473). The paired difference in the proportion of transducers having all CFUs eliminated between LLD and HLD was -1.0% (95% CI: -2.4 to -0.2%, P-value <.001).

CONCLUSIONS

Disinfection with LLD is noninferior to HLD when microorganisms from skin have contaminated the transducer. Therefore, using LLD for US transducers involved in percutaneous procedures would present no higher infection risk compared with HLD.

Infection Control for Perioperative Ultrasonography and Echocardiography

Ultrasound technology has revolutionized point-of-care diagnostics, decision-making, and the guidance of interventional procedures in Anesthesiology and Perioperative Medicine. Recent literature has highlighted important infection control considerations when performing transesophageal or transthoracic echocardiography, point-of-care ultrasound, and ultrasound-guided procedures. This narrative review focuses on operator precautions and disinfection methods and summarizes key recommendations from the international Echocardiography and Radiology Societies.

Anaesthetist’s adherence to aseptic ultrasound practices when performing Ultrasound Guided Peripheral Intravenous Cannulation (USGPIVC). A quality improvement project

Background: Sterile ultrasound covers and conducting mediums are recommended when performing ultrasound guided percutaneous procedures to minimise risk of infection to the patient. Purpose manufactured ultrasound transducer cover kits meet these requirements. Transparent dressings meet some of these requirements however, they are not approved for use as ultrasound transducer covers. We recognised that our departmental practice may not adhere to these standards. Objective: The primary objective was to identify and improve the rate of adherence to the recommended aseptic precautions by anaesthetists performing ultrasound guided percutaneous procedures at the Department of Anaesthesia, Royal Brisbane and Women’s Hospital, the largest tertiary referral hospital in Queensland, Australia. Secondary objectives were to identify types and rates of use of various probe covers and ultrasound conductive mediums used. Design: A complete quality improvement cycle was undertaken using a plan, do, study, act model. Methods: Firstly, a departmental wide voluntary survey was distributed in March 2019 focused on practitioner’s baseline aseptic practices for ultrasound guided peripheral intravenous cannulation (USGPIVC). Subsequently a suite of interventions were undertaken between May 2019 to April 2020 focusing on highlighting recommended aseptic practices through the use of high-quality sterile transducer covers and sterile conducting mediums for all ultrasound guided percutaneous procedures. Components of the intervention included the development of a departmental policy, educational activities, and improving equipment availability and access. A post- intervention follow up audit was repeated in April 2020 to measure changes in practice. Results: Of 134 anaesthetic consultants or trainees 58 completed the pre-intervention survey and 47 completed the post- intervention survey. After the intervention the use of recommended transducer covers and conducting mediums increased from 10.3% to 76.6% and 58.6% to 83.0% respectively. Participants were more likely to choose both a recommended transducer cover and conducting medium than at least one non-recommended option ([OR] 20.4, 95% CI: 7.1 - 58.4). There was a 122% increase in the number of recommended transducer cover kits ordered when comparing stock inventory over a six-month period before and after the intervention. Conclusion: Adherence to the recommended aseptic precautions for USGPIVC improved after the implementation of educational interventions.

Incidence of infectious complications following ultrasound-guided percutaneous musculoskeletal interventions with the use of an uncovered transducer footprint

OBJECTIVES

To determine the incidence of infectious complications following ultrasound-guided musculoskeletal interventions performed with a disinfected uncovered ultrasound transducer footprint.

METHODS

Electronic medical records of all patients who underwent an ultrasound-guided musculoskeletal procedure (including injection, calcific lavage, or ganglion cyst aspiration) performed by any of the 14 interventional musculoskeletal radiologists at our institution between January 2013 and December 2018 were retrospectively reviewed to identify procedure site infections. Biopsies and joint aspirations were excluded. The procedures were performed using a disinfected uncovered transducer footprint. First, an automated chart review identified cases with (1) positive answers to the nurse's post-procedure call, (2) an International Classification of Diseases (ICD) diagnostic code related to a musculoskeletal infection, or (3) an antibiotic prescription within 30 days post-procedure. Then, these cases were manually reviewed for evidence of procedure site infection.

RESULTS

In total, 6511 procedures were included. The automated chart review identified 3 procedures (2 patients) in which post-procedural fever was reported during the nurse's post-procedure call, 33 procedures (28 patients) with an ICD code for a musculoskeletal infection, and 220 procedures (216 patients) with an antibiotic prescription within 30 post-procedural days. The manual chart review of these patients revealed no cases of confirmed infection and 1 case (0.015%) of possible site infection.

CONCLUSIONS

The incidence of infectious complications after an ultrasound-guided musculoskeletal procedure performed with an uncovered transducer footprint is extremely low. This information allows radiologists to counsel their patients more precisely when obtaining informed consent.

KEY POINTS

• Infectious complications after ultrasound-guided musculoskeletal procedures performed with a disinfected uncovered transducer footprint are extremely rare.

Ultrasound-guided regional anesthesia in COVID-19 and future pandemics: infection control

PURPOSE OF REVIEW

Infection control is inherent in ultrasound-guided regional anesthesia practice, because ultrasound transducer and coupling gel can be vectors for pathogen transmission. We reviewed the current standards and recommendations of ultrasound transducer cleaning, disinfection, and safe handling of ultrasound equipment. Based on the available data, we propose a set of practical recommendations applicable to coronavirus disease 2019 (COVID-19) pandemic and future epidemics.

RECENT FINDINGS

Regional anesthesia is often preferred over general anesthesia for COVID-19 patients. Avoidance of general anesthesia reduces the need for aerosol generating procedures. Administration of ultrasound-guided regional anesthesia and surgery under regional anesthesia in COVID-19 patients requires careful infectious precautions to prevent the viral spread through the use equipment.

SUMMARY

Ultrasound machine, transducer and coupling gel can serve as a vector for transmission of pathogens. In the era of COVID-19 pandemic, standardized strategies are recommended to minimize the risk of spread of COVID-19 to both patients and the healthcare providers.