One of the causes of patients getting sick in hospital is the transfer of bacteria from one patient to the other (nosocomial infection). This transfer of bacteria can lead to serious illness, even death. There are numerous precautions taken in hospital to prevent this, such as hand washing, wearing gloves, sterile gowns and gloves during procedures etc. There has been a tremendous growth in the use of point of care ultrasound to assist clinicians in the Emergency Department, Intensive Care Unit and Anaesthetic Department. We suspect that probes, which are in contact with patients’ skin are not cleaned as often or as thoroughly as they should be. This might lead to bacterial colonization.
Often the ultrasound probes are used to assist with invasive procedures such as the placement of central and peripheral venous catheters. There is a potential for the probes to be contaminated by patients’ blood during these procedures, as well as their skin bacteria. This situation would clearly pose a risk to the well being of our patients and staff, and these procedures are most commonly performed on our sickest, most at risk patients.
We aim to investigate the bacterial colonization and blood contamination on ultrasound probes in the Emergency Departments and Intensive Care Units across numerous hospitals in South East Queensland. The amount of bacteria, the type of bacteria and the amount of blood contamination will be investigated and reported. This study has the potential to demonstrate possible contamination of our sickest patients by blood and pathogenic bacteria from ultrasound probes used by the clinicians who are caring for them. The results should lead to recommendations regarding standardised work practices for the use of this equipment in the Intensive Care Unit and the Emergency Department.
We performed 109 tests for blood and 131 tests for microbial contamination, with 61% of samples testing positive for blood contamination (95% CI, 52%-71%) and 48% testing positive for microbiological contamination (95% CI, 40%-57%). Transducer leads and transducers had high blood contamination (88% and 57%, respectively) and microbiological contamination (62% and 46%, respectively). Equipment from ICUs was less likely to test positive (odds ratio, 0.55; 95% CI, 0.37-0.79). Only 51% of blood-contaminated samples were visibly stained, and visible staining was not associated with microbiological contamination (57%; P=1).
Our results show significant contamination of ultrasound equipment, and that visual inspection of equipment is neither sufficient nor reliable in excluding contamination. Ultrasound equipment is a possible factor in the transmission of infectious diseases in EDs and ICUs. Guidelines must be formulated, disseminated and rapidly adopted to ensure the safety of the most acutely ill patients exposed to ultrasound procedures in acute care settings.
- Keys M., Sim B.Z., Thom O., Tunbridge M., Barnett A.G., Fraser J.F., "Efforts to Attenuate the Spread of Infection (EASI): a prospective, observational multicentre survey of ultrasound equipment in Australian emergency departments and intensive care units", 'Crit Care Resusc.', 2015; 17(1):43-6
Trainee Grant Scheme
Dr Ogilvie Thom
A/Prof Adrian Barnett