///2010 Abstract Details
2010 Abstract Details2018-05-01T17:52:49+00:00

A UK national survey on the use of filter needles in drawing drugs for intrathecal use

Abstract Number: 97
Abstract Type: Other

Biju Kurian MBBS, FRCA, FCARCSI, PGA1 ; Naresh Sandur MBBS, MD, FRCA2; Sathya Jaganathan MBBS, FRCA3; Khalid Hasan MBBS, FRCA4

Introduction: Existing literature shows that glass particle contamination occurs upon opening of glass ampoules.1 The use of filter needles, to aspirate drugs from glass ampoules, has been shown to significantly reduce glass particle contamination.2 In the majority of hospitals in UK, drugs for intrathecal (spinal) use are presented in single-use glass ampoules. We present the results of a national survey on the use of filter needles in drawing up drugs for intrathecal use.

Methods: A web link to an online questionnaire was sent to all the NHS anaesthetists in UK, through their department secretaries. We received responses from 1171 anaesthetists, which included 623 consultants, 103 Associate Specialists and Staff Grades, and 413 trainees. 44% of the respondents were involved in providing obstetric anaesthesia.

Results: 4.4% (n=51) and 6.7% (n=78) do not use a filter needle to draw up the intrathecal dose of local anaesthesia and adjuvant drug, respectively. The majority, 77.6% (n=904), draw up the local and the adjuvant in different syringes and then mix the two prior to injection. Of these, 16.2% (n=154), mix the two by injecting from one syringe into the other through the same filter needle, thus negating the purpose of the filter. The majority, 60% (n=569), however, mix the two using a separate non-filter needle. 16% (n=193) draw the LA and the adjuvant into the same syringe. A small number, 2.8% (n=33), inject the LA and the adjuvant separately.

Discussion: The results show that a significant number of anaesthetists do not use a filter needle, and a greater number, use it incorrectly. If the results are extrapolated to the whole anaesthetic body, an alarming number of patients are being exposed to glass particles either by omission or the incorrect use of filter needles.Animal studies have shown that glass particles can cause inflammatory reactions and granuloma formation in various body tissues.3 In the interest of patient safety, the correct use of a filter needle can mitigate the risk of instilling glass particles into the intrathecal space. Another aspect that needs to be considered, is the potential microbiologic contamination caused by these galss particles, and the need for micro filters.


1.Carbone-Traber K, Shanks C. Glass particle contamination in single-dose ampoules. Anaesthesia 1986;65:1361-1363.

2.Sabon RL, Cheng EY, Stommel KA, Hennen CR. Glass particle contamination: Influence of aspiration methods and ampoule types. Anaesthesia 1989; 70:859-862.

3.Waller DG, George CF. Ampoules, infusions and filters. Br Med J 1986; 273:714

SOAP 2010