Ultrasound gel causes
inflammation in subcutaneous
tissue and muscle in Wistar rats
Dr Paul Lee-Archer
Royal Children’s Hospital
Brisbane, Australia
Background
 Ultrasound guided procedures are
increasingly being used in anaesthesia
 Hollow needles introduce small amounts of
gel into tissues
 Ultrasound gel is designed to be topical
only, its safety as an injectable has not
been assessed
 This study aimed to determine what effect
ultrasound gel has on subcutaneous tissue
and muscle
Background
 Current evidence mainly limited to
case reports of contact dermatitis
 Preservatives and stabilisers
implicated in these reactions
 Infection/contamination risk
 Report of cell lysis in FNA samples
contaminated with gel
 Exact composition of gels not always
known
Methods
 20 Wistar rats anaesthetised and
injected with Parker Aquasonic 100
sterile ultrasound gel
 Two injection sites:
 Subcutaneously in chest
 Intramuscularly in thigh
 Corresponding sites on opposite side
of the body injected with saline to act
as a control
Methods
 After seven days the rats were
euthanised, sites examined and tissue
harvested
 Slides of the tissue samples were
prepared
 The examining pathologist was
blinded as to which samples were
controls
Results
 Macroscopically, the ultrasound gel
injection sites developed a hard,
mobile lump and some skin necrosis
 Microscopically all the ultrasound gel
samples exhibited a florid
inflammatory reaction
 The presence of giant cells suggests a
foreign-body reaction
Results
Fig 1. Site of subcutaneous ultrasound gel injection
exhibiting swelling and skin necrosis seven days after
injection.
Conclusions
 Ultrasound gel causes inflammation in
rat tissue
 Limitations:
 Rat model may not be representative
 Relatively large volumes used
 Only one brand of ultrasound gel tested
 Is there any clinical relevance?
Conclusions
 Possible solutions
 Avoid injecting through a layer of gel
 Use a different medium such as sterile
water
 Develop a new ultrasound gel that is safe
to inject
References
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1. Belavy D. Regional Anesthesia Needles Can Introduce Ultrasound Gel into Tissues. Anesth Analg. 2010 Sept; 111: 811-812.
2. Ando M, Ansotegui J, Munoz D, Fernandez de Corres L. Allergic contact dermatitis from imidazolidinyl urea in an ultrasonic gel.
Contact Dermatitis 2000; 42: 109-110.
3. Ayadi M, Martin P, Bergoend H. Contact dermatitis to a carotidian
Doppler gel. Contact Dermatitis 1987; 17: 118-119.
4. Eguino P, Sánchez A, Agesta N, Lasa O, Ratón JA, Díaz-Pérez JL. Allergic
contact dermatitis due to propylene glycol and parabens in an ultrasonic gel.
Contact Dermatitis. 2003 May; 48(5): 290.
5. Erdmann SM, Sachs B, Merk HF. Allergic contact dermatitis due to methyldibromoglutaronitrile in Euxyl K 400 in an ultrasonic
gel. Contact Dermatitis. 2001 Jan; 44(1): 39-40.
6. Gebhart M, Stuhlert A, Knopf B. Allergic contact dermatitis due to Euxyl K 400
in an ultrasonic gel. Contact Dermatitis. 1993 Nov; 29(5): 272.
7. Horiguchi Y, Honda T, Fujii S, Matsushima S, Osaki Y. A case of allergic
contact dermatitis from propylene glycol in an ultrasonic gel, sensitized at a
leakage skin injury due to transcatheter arterial chemoembolization for
hepatocellular carcinoma. Int J Dermatol. 2005 Aug; 44(8): 681-3.
8. Kessler J, Schafhalter-Zoppoth I, Gray AT. Allergic contact dermatitis caused
by ultrasonic gel. Reg Anesth Pain Med. 2006 Sep-Oct; 31(5): 480-1.
9. Khan IJ, Azam NA, Goyal R, Nabi NU. Contact urticaria to ultrasonic gel. Eye
(Lond). 2007 Jul; 21(7): 1016.
10. Leitner B, Hemmer W, Focke M, Gotz M, Jarisch R. Contact dermatitis against ultrasonic gel. Dermatosen in Beruf und Umwelt.
1999; 47(4): 164-165.
11. Uter W, Schwanitz HJ. Contact dermatitis from propylene glycol in
ECG electrode gel. Contact Dermatitis 1996; 34: 230-231.
12. Villa A, Venegoni M, Tiso B. Cases of contact dermatitis caused by
ultrasonographic gel. J Ultrasound Med. 1998 Aug; 17(8): 530
13. Hutchinson J, Runge W, Mulvey M, Norris G, Yetman M, Valkova N, Villemur R, Lepine F. Burkholderia cepacia Infections
Associated with Intrinsically Contaminated Ultrasound Gel: The Role of Microbial Degradation of Parabens. Infect Control Hosp
Epidemiol. 2004; 25(4): 291-296.
14. Molyneux AJ, Coghill SB. Cell Lysis Due to Ultrasound Gel in Fine Needle Aspirates: An Important New Artefact in Cytology.
Cytopathology. 1994; 5:41–45.
15. Sinha R, Punj J, Pandey R. Use of saline infusion instead of gel for ultrasound-guided (USG) central venous cannulation. Acta
Anaesthesiologica Scandinavica. 2008 May; 52(5): 721.