Jet injector

A health worker using a jet injector on a child

A jet injector is a type of medical injecting syringe that uses a high-pressure narrow jet of the injection liquid instead of a hypodermic needle to penetrate the epidermis. It is powered by compressed air or gas, either by a pressure hose from a large cylinder, or from a built-in gas cartridge, small cylinder, or spring (as in the Medijector Vision, Vitajet, Injex 23 and 30, or Insujet).

Jet injectors are used for mass vaccination, and as an alternative to needle syringes for diabetics to inject insulin. As well as health uses, similar devices are used in other industries to inject grease or other fluid.

The term "hypospray" is largely restricted to science-fiction, but there are cases in scientific periodicals of a real jet injector being called a hypospray.[1][2][3]

Types

A Med-E-Jet vaccination gun from 1980

The Jet Injector Gun and the Ped-O-Jet are air-powered medical injector devices designed to administer vaccinations very efficiently. Invented by Aaron Ismach, these medical devices were bought in mass quantities by the US government and provided to governments around the world to eradicate smallpox and other diseases. Servicemen in the Armed Forces were routinely injected with these medical devices to immunize them, and civilian usage included vaccinations during situations such as flu epidemics. The Jet Injector is powered by electricity, while the Ped-O-Jet version is powered by a foot pump and does not require electricity to administer the vaccines. These devices have various specialized nozzles for different medication densities, and can also be used to inoculate animals.

The Biojector 2000 is a make of gas-cartridge-powered jet injector. It is claimed by its manufacturer that it can deliver intramuscular injections and subcutaneous injections up to 1 milliliter. The part which touches the patient's skin is single-use and can be replaced easily. It can be powered from a big compressed gas cylinder instead of gas cartridges. It is made by Bioject.[4]

The Vision (MJ7) is a compact, spring-powered jet injector. It can deliver up to 1.6ml in 0.03ml increments, and is designed to last 3000 injections. The medication travels through a hole in the needle-free syringe that is about half the diameter of a 30 gauge syringe. The part which touches the patient's skin can be used for a week. The device was designed by Antares Pharma (formerly Medi-Jector). [5]

The PharmaJet Needle-Free Injector delivers vaccines either intramuscularly or subcutaneously by means of a narrow, precise fluid stream syringe that delivers the medicine or vaccine through the skin in one-tenth of a second.[6]

Diabetics have been using jet injectors in the United States for at least 20 years. These devices have all been spring loaded. At their peak, jet injectors accounted for only 7% of the injector market. Currently, the only model available in the United States is the Injex 23. In the United Kingdom, the Insujet has recently entered the market. As of June 2015, the Insujet is available in the U.K. and a few select countries.

Concerns

Because the jet injector breaks the barrier of the skin, there is a potential that biological material is transferred from one user to the next. Some infectious viruses such as hepatitis B can be transmitted by less than one millionth of a millilitre[7] so makers of injectors need to ensure there is no cross-contamination between applications. The World Health Organization no longer recommends jet injectors for vaccination due to risks of disease transmission.[8]

An experiment using mice, published in 1985, showed that jet injectors would frequently transmit the viral infection LDV from one mouse to another.[9] Another study used the device on a calf, then tested the fluid remaining in the injector for blood. Every injector they tested had detectable blood in a quantity sufficient to pass on a virus such as hepatitis B.[7]

From 1984–1985 a weight-loss clinic in Brazil injected a pregnancy hormone into their clients, mostly using a jet injector. It was noted that a number of these patients became sick with hepatitis. When studied, 57 out of 239 people who had received the jet injection tested positive for hepatitis B.[10]

As well as transmission between patients, jet injectors have inoculated bacteria from the environment into users. In 1988 a podiatry clinic used a jet injector to deliver local anaesthetic into patients' toes. Eight of these patients developed infections caused by Mycobacterium chelonae. The injector was stored in a container of water and disinfectant between use, but the organism grew in the container.[11] This species of bacteria is sometimes found in tap water, and had been previously associated with infections from jet injectors.[12]

History

Accidental jet injection

Accidents have happened in vehicle repair garages and elsewhere where one of the following has unintentionally acted as a hypodermic jet injector:

Accidental injection of oil or paint by such high-pressure sprays can cause very serious injuries which may require amputation, and can induce fatal sepsis.

References

  1. ↑ Clarke AK, Woodland J (February 1975). "Comparison of two steroid preparations used to treat tennis elbow, using the hypospray". Rheumatol Rehabil 14 (1): 47–9. doi:10.1093/rheumatology/14.1.47. PMID 1091959.
  2. ↑ Hughes GR (June 1969). "The use of the hypospray in the treatment of minor orthopaedic conditions". Proc. R. Soc. Med. 62 (6): 577. PMC 1811070. PMID 5802730.
  3. ↑ Baum J, Ziff M (March 1967). "Use of the hypospray jet injector for intra-articular injection". Ann. Rheum. Dis. 26 (2): 143–5. doi:10.1136/ard.26.2.143. PMC 1031030. PMID 6023696.
  4. ↑ http://www.bioject.com/
  5. ↑ http://www.wikinvest.com/stock/Antares_Pharma_%28AIS%29/Antares_Medi-jector_Series_Needle-free_Injectors
  6. ↑ "PharmaJet Product Page".
  7. 1 2 Hoffman, P.N; R.A Abuknesha; N.J Andrews; D Samuel; J.S Lloyd (2001-07-16). "A model to assess the infection potential of jet injectors used in mass immunisation". Vaccine 19 (28–29): 4020–7. doi:10.1016/S0264-410X(01)00106-2. PMID 11427278.
  8. ↑ World Health Organization (2005-07-13). "Solutions: Choosing Technologies for Safe Injections". Archived from the original on 21 September 2012. Retrieved 2011-05-06.
  9. ↑ Brink, P.R.G.; Van Loon, M.; Trommelen, J.C.M.; Gribnau, W.J.; Smale-Novakova, I.R.O. (1985-12-01). "Virus Transmission by Subcutaneous Jet Injection". J Med Microbiol 20 (3): 393–7. doi:10.1099/00222615-20-3-393. PMID 4068027.
  10. ↑ Canter, Jeffrey; Katherine Mackey; Loraine S. Good; Ronald R. Roberto; James Chin; Walter W. Bond; Miriam J. Alter; John M. Horan (1990-09-01). "An Outbreak of Hepatitis B Associated With Jet Injections in a Weight Reduction Clinic". Arch Intern Med 150 (9): 1923–1927. doi:10.1001/archinte.1990.00390200105020. PMID 2393323. Retrieved 2011-05-06.
  11. ↑ Wenger, Jay D.; John S. Spika; Ronald W. Smithwick; Vickie Pryor; David W. Dodson; G. Alexander Carden; Karl C. Klontz (1990-07-18). "Outbreak of Mycobacterium chelonae Infection Associated With Use of Jet Injectors". JAMA 264 (3): 373–6. doi:10.1001/jama.1990.03450030097040. PMID 2362334.
  12. ↑ Inman, P.M.; Beck, A.; Brown, A.E.; Stanford, J.L. (August 1969). "Outbreak of injection abscesses due to Mycobacterium abscessus". Archives of Dermatology 100 (2): 141–7. doi:10.1001/archderm.100.2.141. PMID 5797954.
  13. ↑ Rees CE (11 September 1937). "Penetration of tissue by fuel oil under high pressure from diesel engine". JAMA 109 (11): 866–7. doi:10.1001/jama.1937.92780370004012c.
  14. ↑ The DoD order
  15. ↑ Veterans info page
  16. ↑ "PharmaJet's Stratis® Needle-free Injector Receives WHO PQS Certification as a Pre-qualified Delivery Device for Vaccine Administration". FierceVaccines.
  17. ↑ http://www.cdc.gov/flu/protect/vaccine/jet-injector.htm

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