To the Editor:-It can be quite difficult to insert an adequately sized and reliable intravenous cannula into small infants. Small infants frequently arrive in the operating room bearing the scars of multiple previous attempts at venous access, which limit the remaining options. If blood transfusion may be required, it is necessary to have at least a 22-gauge cannula.

I have found that my success rate at the cannulation of very small vessels, e.g., those fine veins on the dorsum of a preterm or small infant's foot, has been much improved by using the following technique. A venous tourniquet is placed and the skin is prepared in the usual fashion. A 22-gauge angiocath (Angiocath; Becton Dickinson Infusion Therapy Systems, Inc., Sandy, UT) is inserted toward the vein at a shallow angle. As soon as there is a “flashback” of blood into the hub of the needle, the cannula is held absolutely still, and the needle is very gently removed. Blood will usually be seen flowing back into the cannula. A 0.018" (0.46-mm dia) spring-wire guide (Spring wire guide AW-04018; Arrow International, Inc., Reading, PA) is now gently advanced through the cannula into the vein. In most instances, this guide wire is easily inserted, even into very small veins, and can be seen tracking inside the vein for some distance up the limb. The cannula is now advanced over the guide wire with full confidence that it will end up lying freely within the lumen of the vein and that it will provide a very reliable intravenous route.

This technique should be considered for all very small infants and especially for those in whom all the “good veins” have already been used, traumatized, or both. During the past month I have used this method in 11 infants, and it has been successful in every case. A former resident, now a practicing pediatric anesthesiologist, has also adopted this method, has proclaimed it to be most useful, and encouraged me to submit this report (R Seal, personal communication, 1998).

David J. Steward, M.B., B.S., F.R.C.P.C.

Professor of Anesthesiology; University of Southern California; Director of Anesthesiology; Children's Hospital Los Angeles; Los Angeles, California;DSTEWARD%SMTPGATE@CHLAIS.USC.EDU

(Accepted for publication November 9, 1998.)