Transcutaneous pressure at which the internal jugular vein is collapsed on ultrasonic imaging predicts easiness of the venous puncture

Even though we use ultrasound guidance for central venous puncture, we sometimes experience difficulties. We infer that in such cases the vein is collapsed and that the transcutaneous ultrasound probe pressure at which the vein is collapsed (P _tc) may predict the easiness of the venous puncture. We measured P _tc and the diameter of the internal jugular vein in 47 adult patients in our ICU. After successful puncture, we also measured venous pressure (P _v). The patients were divided into two groups based on the number of puncture attempts: ≥3 attempts constituted the “difficult group” and <3 attempts was considered the “easy group:” 33 patients were in the easy group and 14 patients were in the difficult group. The easy group showed significantly higher P _tc value (9.3 ± 3.8 vs. 3.5 ± 0.9 cmH₂O, P < 0.0001) and larger vertical diameter (9.2 ± 3.1 vs. 6.8 ± 2.2 mm, P = 0.013) than the difficult group. We observed a clear border between the minimum P _tc in the easy group (6 cmH₂O) and the maximum value in the difficult group (5 cmH₂O). In conclusion, venous collapsibility and vertical diameter determine difficulty in performing venous puncture.