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)

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.

Automated versus manual B-lines counting, left ventricular outflow tract velocity time integral and inferior vena cava collapsibility index in COVID-19 patients

Background and Aims

The incorporation of artificial intelligence (AI) in point-of-care ultrasound (POCUS) has become a very useful tool to quickly assess cardiorespiratory function in coronavirus disease (COVID)-19 patients. The objective of this study was to test the agreement between manual and automated B-lines counting, left ventricular outflow tract velocity time integral (LVOT-VTI) and inferior vena cava collapsibility index (IVC-CI) in suspected or confirmed COVID-19 patients using AI integrated POCUS. In addition, we investigated the inter-observer, intra-observer variability and reliability of assessment of echocardiographic parameters using AI by a novice.

Methods

Two experienced sonographers in POCUS and one novice learner independently and consecutively performed ultrasound assessment of B-lines counting, LVOT-VTI and IVC-CI in 83 suspected and confirmed COVID-19 cases which included both manual and AI methods.

Results

Agreement between automated and manual assessment of LVOT-VTI, and IVC-CI were excellent [intraclass correlation coefficient (ICC) 0.98, P < 0.001]. Intra-observer reliability and inter-observer reliability of these parameters were excellent [ICC 0.96-0.99, P < 0.001]. Moreover, agreement between novice and experts using AI for LVOT-VTI and IVC-CI assessment was also excellent [ICC 0.95-0.97, P < 0.001]. However, correlation and intra-observer reliability between automated and manual B-lines counting was moderate [(ICC) 0.52-0.53, P < 0.001] and [ICC 0.56-0.69, P < 0.001], respectively. Inter-observer reliability was good [ICC 0.79-0.87, P < 0.001]. Agreement of B-lines counting between novice and experts using AI was weak [ICC 0.18, P < 0.001].

Conclusion

AI-guided assessment of LVOT-VTI, IVC-CI and B-lines counting is reliable and consistent with manual assessment in COVID-19 patients. Novices can reliably estimate LVOT-VTI and IVC-CI using AI software in COVID-19 patients.

Preparedness of Australasian emergency departments for point-of-care ultrasound in the COVID-19 pandemic

Introduction

Point-of-care ultrasound (POCUS) has been brought to the limelight again, with a surge in lung ultrasound in suspected COVID-19 patients. This is due to POCUS superiority over chest X-ray, equivalent efficacy to computerised tomography chest for COVID-19 diagnosis and potential minimisation of cross-infection. However, inadequate disinfection practices could make ultrasound machines a vector for disease transmission. This study, conducted during the early phase of the COVID-19 pandemic, surveyed the preparedness of Australasian Clinicians for responsible POCUS practice within the Emergency Department (ED).

Methods

An anonymous online survey conducted from 20th April to 3rd June 2020 among emergency clinicians providing POCUS within Australasian EDs investigated preparedness to provide effective POCUS while minimising cross-infection.

Results

The survey received 171 responses and 116 being eligible for analysis. Most respondents (n = 96, 98%) had a separate 'hot zone' with a dedicated US device (n = 75, 77%), but lacked COVID-19-specific standard-operating procedures (n = 51, 52%) or a designated safety and compliance officer (n = 36, 37%). Most clinicians (n = 86, 88%) were willing to perform ultrasound in highly infectious patients, despite poor formal training (n = 66, 67%) or COVID-19-specific lung protocols (n = 59, 60%). Most (n = 92, 93%) had access to appropriate low-level disinfectant wipes but varied significantly in disinfection practice due to a lack of timely, formal or unified guidelines.

Conclusion

Australasian EDs significantly lacked investment in education, training and protocols to conduct safe POCUS in the COVID-19 pandemic. A framework with evidence-based, logistically feasible protocols supporting safe emergency POCUS is required to deal with similar future infectious outbreaks.