Potential Adverse Ultrasound-related Biological Effects

Abstract

Ultrasound energy exerts important cellular, genetic, thermal, and mechanical effects. Concern about the safety of ultrasound prompted several agencies to devise regulatory limits on the machine output intensities. The visual display of thermal and mechanical indices during ultrasound imaging provides an aid to limit the output of the machine. Despite many animal studies, no human investigations conducted to date have documented major physiologic consequences of ultrasound exposed during imaging. To date, ultrasound imaging appears to be safe for use in regional anesthesia and pain medicine interventions, and adherence to limiting the output of ultrasound machines as outlined by the Food and Drug Administration may avoid complications in the future. This article reviews ultrasound-related biologic effects, the role of the regulatory agencies in ensuring safety with the use of ultrasound, and the limitations and implications of ultrasound use in humans. P IERRE Curie's discovery of the piezoelectric effect in 1880 launched the ultrasound technology revolution. This technology was first applied in ships for depth detection and in metallurgy for fracture identification, but medical applications were soon appreciated shortly thereafter.1 Medical ultrasound imaging has been used extensively for more than five decades, and the variety of uses for which this technology is used expanded rapidly. For example, the use of ultrasound for interventions during regional anesthesia and pain medicine allows the practitioner to reliably see the target, needle, and injectate with good resolution. 2 The primary advantages of ultrasound in these settings include real-time assessment, absence of radiation, decreased cost, and portability.2

Ultrasound Investigation and the Eye

“…As such, we reanalyzed the data (SctO 2 against SjvO 2 ) by using a Bland-Altman plot with multiple measurements per subject. 3 Nevertheless, we found little change in the 95% limit of agreement (from −37.8% to +23.6% with mean difference −7.2) compared with that (−38.2%, 23.8% with mean difference −7.2) of our previous data. 1 In fact, we used a Bland-Altman plot with multiple measurements per subject in another study and demonstrated a lack of agreement of SctO 2 and SjvO 2 values during the surgery in the beach chair position.…”

“…3 Our data showed significant changes in intraorbital temperature after exposure to the nonorbital rated Sonosite Micromaxx 6-13 MHz linear transducer (Bothell, WA).…”

“…They have also shown that this thermal effect is time dependent. In our study, two trained investigators made all measurements, and strict attention was paid to decrease exposure time to ultrasound to less than 60 s. As has recently been highlighted, 3 "minimizing the exposure time is probably the most important factor for ensuring patient safety from thermal injury." Moreover, in our study, applying the probe on a thick layer of ultrasound gel over the closed upper eyelid could have decreased the heat transfer.…”

The American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, and the Asian Australasian Federation of Pain Societies Joint Committee Recommendations for Education and Training in Ultrasound-Guided Interventional Pain Procedures

“…The pain physician should limit and minimize the use of ultrasound to only the time necessary to perform each procedure. 16 …”

Ultrasound guided chronic pain interventions (Part I)

“…However, long-term clinical effects of tissue heating and cavitation is not known yet. [11] In pain treatment, US is used in interventions performed on peripheral nerves, neuroaxial structures and musculoskeletal structures. These common interventions are listed below:…”