Randomised experimental comparison of 23G versus 22G needle for ultrasound guided invasive fetal procedures
Fetus, ultrasound, amniocentesis, fetal membranes, fetal surgery
Published online: Jul 29 2010
Abstract
Objectives: To experimentally compare the standard 22G spinal needle with a newer 23G needle with specific ultrasound visualisation tip (Cook echotip®, Spencer, Indiana, USA) in the setting of ultrasound-guided invasive intrauterine procedures.
Materials and Methods: We first determined the size of the defects created in human fetal membranes using light microscopy and adapted area calculating software by both needles in an in vitro model performing 20 paired experiments on 4 term membrane specimens. Secondly, we determined the performance of 3 groups of operators, with different levels of experience in invasive intrauterine procedures during cordocentesis on a simulator model, using either a 22G or 23G needle. For each procedure, we measured the time required to successfully obtaining 2 ml of artificial blood in 24 paired experiments.
Results: The mean ± SD defect sizes created was 0.66 ± 0.12 mm2 with
the 22G needle and 0.59 ± 0.13 mm2 with the 23G needle (P = 0.11). The
mean duration of sampling was 144 ± 188 sec with the 22G needle versus
140 ± 120 sec
with the 23G needle (P = 0.99) for all operators pooled but four out of
six operators showed shorter sampling times with a 22G needle.
Conclusion: This experimental study shows that the use of a 23G needle
compared to a 22G needle was not associated
with significantly different procedure duration or defect size.
