Paediatric venepuncture and peripheral intravenous access — viva

Opening (must-hit)

"Paediatric venepuncture is a single needle puncture to draw blood, while peripheral intravenous cannulation places an indwelling cannula for ongoing therapy. In a child both succeed or fail on the right site, the right comfort and the right operator. I choose the site by age — the dorsal hand veins first, then the antecubital fossa, the forearm and the great saphenous at the ankle — and match the gauge to the child: 24G for the neonate and infant, 22G for the infant and small child, 20G for the older child, 18G for the adolescent or a rapid bolus. I apply a comfort bundle in advance — topical anaesthesia at the correct lead time, sucrose in the infant, distraction and comfort positioning — and I let no operator make more than two attempts. When surface veins fail I use ultrasound-guided access, and in arrest I go straight to intraosseous access." [6] [7] [9]

Branch A — Site and gauge

Examiner: A 2-year-old needs a cannula. What site and gauge do you choose? Candidate: I start distally on the dorsum of the non-dominant hand, because the veins are superficial and easy to secure and a distal site leaves proximal options open. I would use a 22G (blue) cannula for an infant or small child, and I have the next size up and down ready. The principle is the smallest cannula, the largest gauge number, that delivers the therapy. [6]

Branch B — The comfort bundle

Examiner: How do you keep this child calm and pain-free? Candidate: I apply a comfort bundle as a procedural step. For a non-emergency needle I apply topical anaesthesia at the correct lead time — EMLA about 60 minutes before, Ametop about 30 to 45 minutes, or LMX4 about 30 minutes — and occlude it. I give oral sucrose at about 1 to 2 millilitres two minutes before in an infant. I position the child on a parent's lap, use age-appropriate distraction, and commit a single calm operator. The point is that comfort is what makes the vein appear, because a frightened child's vessels constrict. [7] [9]

Branch C — The difficult-access child

Examiner: The hand veins are gone after two attempts. What now? Candidate: I stop, call a senior, and go to ultrasound-guided peripheral access. I use a linear high-frequency probe, find a compressible anechoic vein in the short axis, centre it, and insert the cannula out-of-plane, advancing in small increments and watching the tip tent the wall then flash. The vein compresses; the artery does not — compressibility is the key sign. If this fails or the child deteriorates, I move to intraosseous access. [1] [2]

Branch D — The shocked child

Examiner: The child is now in septic shock. How does that change your plan? Candidate: Peripheral access is now both most urgent and least likely to succeed, because vasoconstriction has hidden the veins. I go to ultrasound early, keep intraosseous access ready, and place the largest cannula the vein allows so a bolus runs fast. I never let a hunt for a peripheral line delay resuscitation. The APLS rule is to move to intraosseous access within about 90 seconds of failed peripheral attempts in an emergency, or as the first route in a shocked child with no obvious vein. [2] [6]

Branch E — A complication at the site

Examiner: A running cannula becomes swollen, painful and discoloured. What is happening and what do you do? Candidate: This is an extravasation injury, and if a vesicant was running it can cause tissue necrosis. I stop the infusion immediately, leave the cannula in to aspirate any residual drug, elevate the limb, mark the area, inform senior staff, and assess for compartment syndrome. Plastic surgery referral may be needed for a large vesicant injury. I never continue an infusion against resistance or swelling. [6]

Branch F — The neonate and EMLA

Examiner: You are about to apply EMLA to a 4-week-old preterm infant for a blood sample. Any concern? Candidate: Yes. EMLA contains prilocaine, which carries a risk of methaemoglobinaemia in the preterm infant and in infants under about three months, so I avoid EMLA in this age group and use alternative comfort measures. For the neonate I use a 24G cannula on the hand or scalp, guard the volume I draw, and remember that umbilical venous access is available in the first week. [7]

Branch G — After the cannula is in

Examiner: The cannula is placed and flushes easily. What now? Candidate: I secure it with a transparent dressing, confirm patency with a free flush and no swelling, document the site, gauge, date and operator, date-label the dressing, set a review and a removal plan, and monitor for infiltration and phlebitis. I use it only while clinically needed — routine replacement every few days is no longer recommended. [6]