Letters

Problems during infusions

BMJ 1995; 310 doi: https://doi.org/10.1136/bmj.310.6989.1271 (Published 13 May 1995) Cite this as: BMJ 1995;310:1271

Severe electrical shock occurred during use of Welmed P1000 syringe pump

  1. P Ford,
  2. D Wood
  1. Consultant anaesthetist Chief medical electronics officer Intensive Care Unit, Wigan Trust Hospitals, Wigan WN1 2NN

    EDITOR,—The Welmed P1000 syringe pump is the earliest of 15 pumps purchased between 1990 and 1993 in our intensive care unit. It is powered by both a back up battery and the mains; when static it is powered by the mains to charge the back up battery.

    A male nurse who was supervising a ventilated patient grasped this pump at either end between both hands. It was attached in series with four others to a drip stand. He received an immobilising electric shock lasting roughly 15 seconds. By kicking over the drip stand he detached himself from the pump. He developed a sinus tachycardia (200 beats/min), hypertension (170/110 mm Hg), and involuntary contractions of his forearm muscles. All resolved within 40 minutes, but upper limb girdle pain persisted for three days.

    When the pump was opened a small quantity of clear fluid was found around the junction between the upper and lower halves. The base mouldings contained further fluid. Over the circuit board was a protective cardboard screen saturated by fluid, which had apparently conducted the current from the mains cable to the outer metallic base plate. Insulating plastic was layered over only half of the inner surface of the base. The pump has no sealign device between the top and bottom of the casing.

    Routine service examinations by our electronics department six months earlier had found small amounts of brown opaque fluid in the cases of eight of these pumps. When the manufacturer was informed it acknowledged having received similar reports from other hospitals. It had no explanation for this finding. It had, however, incorporated a seal into the new models.

    We believe that, despite the inclined plane to the casing, fluid migrated by capillary attraction into the pump, having broached the junction of the case. This hypothesis is based on observation of fluid and crystallised deposits on the inner surface of the eight contaminated pumps. Leaking infusion bags or syringes are the presumed source of the extraneous fluid. Furthermore, saline solutions could promote the conduction of electrical current through the equipment.

    The Medical Devices Directorate (Department of Health) has been contacted, the manufacturers alerted again, and all our pumps re-examined. Drips are positioned clear of the syringe pumps, and syringes are repeatedly checked for leaks while in use. A “non-contact power sensor” is now used to check the electrical stability of all pumps.

    We wish to alert all users to this potentially fatal hazard.

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