title: Flush volumes delivered from pressurized bag pump flush systems in neonates and small children.
abstract: BACKGROUND
  The aim of this study was to measure the volumes of fluid delivered with a fast flush bolus from a flow regulating device.
  
  
  METHODS
  In-vitro fast flush bolus volumes, the volumes delivered from a bag pump flush system while opening the flow regulating device for 1, 2 or 5 s, were gravimetrically measured through a 22-G and a 24-G cannula. In-vivo 1- and 2-s fast flush bolus volumes and the volume required to purge the tubing between stopcock and arterial cannula from visible blood after blood sampling were recorded in 12 anaesthetized neonates and infants (mean age 2.17 +/- 1.97 months, range 0.26-5.37 months) with a 24-G radial arterial cannula by continuously weighing the bag pump flush system at manometer pressures of 100, 200 and 300 mmHg.
  
  
  RESULTS
  In-vitro fast flush bolus volumes ranged from 0.23 +/- 0.04 ml (1-s, 100 mmHg, 24-G cannula) to 2.95 +/- 0.38 ml (5-s, 300 mmHg, 22-G cannula). Volumes were larger using a 22-G cannula than a 24-G cannula (P < 0.01) and increased with longer flushing periods (P < 0.0001) and higher manometer pressures (P < 0.0001). In-vivo 1- and 2-s fast flush bolus volumes correlated well with driving pressures (infusion pressure minus mean arterial pressure) (r2 = 0.81/0.72). 1-s fast flush bolus volumes delivered (ml) were 0.0025 x mmHg driving pressure and 2-s fast flush bolus volumes delivered (ml) were 0.0043 x mmHg driving pressure. The mean volume delivered to purge blood from the arterial pressure tubing was 0.94 +/- 0.18 ml (range 0.61-1.34 ml).
  
  
  CONCLUSIONS
  Fast bolus flushing from pressurized infusion bag systems, using the flow regulating device tested, can be applied during neonatal and paediatric anaesthesia without delivering uncontrolled amounts of fluid.
authors.affiliation: Department of Anaesthesia, University Children's Hospital Zurich, Switzerland.
authors.forename: Anita
authors.initials: A
authors.lastname: Cornelius
authors.forename: Christian
authors.initials: C
authors.lastname: Balmer
authors.forename: Maja I
authors.initials: MI
authors.lastname: Hug
authors.forename: Andreas Ch
authors.initials: ACh
authors.lastname: Gerber
authors.forename: Markus
authors.initials: M
authors.lastname: Weiss
mesh_terms: D000704:Analysis of Variance; D000758:Anesthesia; D002404:Catheterization; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D007231:Infant, Newborn; D007260:Infusion Pumps; D012044:Regression Analysis; D013997:Time Factors