Circulation 107,515 • Volume 27, No. 3 • Winter 2013   Issue PDF

Coring and Fragmentation May Occur With Rubber Cap and Blunt Needles

Tariq Chaudhry, MD; Andrew Serdiuk, DO
Coring example

A cored piece of propofol rubber cap after the cap was pierced with a blunt tip plastic needle to draw the medication. Such contamination has been linkedto latex sensitivity and fragment embolization.

A 45-year-old female was being prepared for induction of general anesthesia for a total thyroidectomy. An induction dose of propofol was drawn through a disposable syringe attached to a blunt plastic needle to pierce the rubber stopper. After the needle was withdrawn, a dark object was seen at the bottom of the propofol vial. Upon close inspection, a cored piece of rubber from the vial’s rubber stopper was identified (Figure).

The issue of coring, the shearing off of a portion of the rubber stopper from a medication vial as it is pierced has been described in the past. The frequency of such incidents seems to be rising as the use of blunt plastic tips increases. Per one study, the incidence of coring was 29% with blunt plastic needles as opposed to only 4% with acutely beveled sharp steel needles.1 The cored fragments can be difficult to visualize because of their small size, the masking effect of the vial labels, or the medication opacity.

Exposure to the macro and microscopic rubber fragments has been linked to latex allergy as well as embolization into small vessels causing ischemia.2 Aspiration of a cylinder shaped rubber core back into the syringe followed by introduction into a patient’s blood stream might seem an unlikely combination of events. A case of near-embolization of the rubber core from a propofol vial that lodged itself into the 24-gauge angiocath interrupting the propofol infusion and setting off the high-pressure pump alarm during a rigid bronchoscopy has been reported.3

Microscopic rubber particles can contaminate the medication and upon systemic administration may cause latex allergy. Isolated cases of systemic reactions to latex allergens have been reported and often associated with the use of multidose vials.4

The amount of latex protein in the multidose vials was determined to be extremely low in 1 study after the rubber stopper was punctured 40 times.5 As we try to protect personnel and patients from the dangers of needle sticks, we may be increasing exposure of our patients to unintended risks.

he use of blunt needles with filters may prevent aspiration of the macro rubber particles. Removing the rubber stopper from the vial altogether addresses the macro or microscopic particle contamination concerns but may increase the potential for errors in dosage, dilution, contamination, and waste.6 Each health care institution should therefore formulate management guidelines for the use of multidose vials in the care of latex-sensitive patients.

Tariq Chaudhry, MD

Andrew Serdiuk, DO

Moffitt Cancer Center

Tampa, Florida


  1. Wani T, Govinda R, Wadhwa A. Studying incidence of coring in anesthesia practice and difference between blunt and sharp needles. [abstract] Anesthesiology 2008;109:A368.
  2. Sakai O, Furuse M, Nakashima N. Cut-off fragments of rubber caps of bottles of contrast material: Foreign bodies in the drip infusion system. Am J Neuroradiol 1996;17:1194-5.
  3. Riess ML, Strong T. Near-embolization of a rubber core from a propofol vial. Anesth Analg 2008;106:1020-1.
  4. Vassallo SA, Thurston TA, Kim SH, Todres ID. Allergic reaction to latex from stopper of a medication vial. Anesth Analg 1995;80:1057-8.
  5. Yunginger JW, Jones RT, Kelso JM, Warner MA, Hunt LW, Reed CE. Latex allergen contents of medical and consumer rubber products. [abstract] J Allergy Clin Immunol 1993;91:241.
  6. Senst BL, Johnson RA. Latex allergy. Am J Health Syst Pharm 1997;54:1071-5.