Use of a large bore syringe creates significantly fewer high intensity transient signals (HITS) into a cardiopulmonary bypass system than a small bore syringe.
BACKGROUND
High intensity transient signals (HITS) have been reported to occur following perfusionist intervention during cardiac surgery. This study investigates the relationship of the syringe bore, injection rate, and HITS created.


METHODS
Syringes (10 mL) with a male luer-lock connection (Large Bore) and Abboject 'jet syringes' with a 20 GA needle and male luer-lock connector (Small Bore) were filled with 10 mL of 0.9 N saline. A perfusionist was randomly assigned a set of four similar syringes followed by the other syringe bore. Each of the four syringes was injected into an in vitro saline-primed cardiopulmonary bypass (CPB) system over 5, 10, 15, or 20 sec. Sixteen randomizations of small and large bore syringes were completed at the four injection times (128 injections). HITS in the CPB arterial line were detected with transcranial Doppler (TCD) probes, were recorded for the 2 min following the injection, and were counted independently off-line by two reviewers.


RESULTS
The use of a large bore syringe compared to a small bore syringe created significantly fewer HITS (29 +/- 6 versus 145 +/- 17 [mean +/- SEM], p<0.001) introduced into the CPB arterial line. Injection over a longer time produced significantly fewer HITS than shorter injection times (p<0.001).


CONCLUSIONS
Significantly fewer HITS are introduced into the CPB system by using standard syringes and slower injection time.
Geriatric Research Education and Clinical Center, VA Boston Healthcare System, Boston 02130, USA. jrudolph@partners.org
James L
JL
Rudolph
Daniel
D
Tilahun
Patrick R
PR
Treanor
Val E
VE
Pochay
Meetali A
MA
Mahendrakar
Praveen
P
Sagar
Viken L
VL
Babikian
D002315:Cardiopulmonary Bypass / Q000295:instrumentation* / Q000379:methods; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000517:prevention & control*; D013594:Syringes / Q000009:adverse effects* / Q000592:standards*; D013997:Time Factors; D017585:Ultrasonography, Doppler, Transcranial