M/29 Bullpup has been evaluated in internal medicine wards and by dedicated vascular-access teams. These are the key results, with links to the sources.
Peer-reviewed · 2026
M/29 vs a guidewire midline: same dwell, far fewer occlusions
University Clinical Centre, Medical University of Warsaw, Poland · retrospective, 2021–2024 · 78 M/29 vs 399 direct-Seldinger long peripheral catheters
2.7%removed for occlusion with M/29, vs 21.8% with the guidewire catheter
62.7%removed because therapy ended, vs 44.5%
10.2 daysmean dwell with M/29 (9.3 with the comparator), no significant difference
7 daysmedian dwell in both groups. M/29 matched the guidewire catheter on longevity
The authors conclude that long peripheral catheters are a safe and effective option for prolonged therapy, and that device factors such as occlusion can drive complication rates even when dwell times are similar.
Sarek MM, Latos M. Comparison of use and maintenance of two types of long peripheral intravenous catheters inserted using the direct Seldinger technique and the over-the-needle method – a retrospective study. Problemy Pielęgniarstwa 2026;34(2). Read the article
Peer-reviewed · 2025
Safe, rapid access in internal medicine, including vasopressors
Rambam Health Care Campus, Haifa, Israel · retrospective observational · 109 patients, 128 catheters
13complications per 1,000 catheter-days
8.8 daysmean dwell time
22patients received vasopressors through the M/29 without complications
21%of patients were discharged home with the line for continued therapy
65.6% of insertions succeeded at the first attempt, in a population with many difficult-access patients. The authors describe the device as a safe, rapid and effective means of venous access, well suited to point-of-care use.
Weber Y, Cohn-Schwartz D, Khamis S, Neuberger A, Berger G. Safety and efficacy of a new long peripheral catheter in hospitalized patients – a retrospective observational study. SAGE Open Medicine 2025;13:20503121251337197. Read the article
Congress · WoCoVA 2022
460 M/29 insertions in one year by a hospital PICC team
Motol University Hospital, Prague, Czech Republic · 1,156 long peripheral catheters inserted by the PICC team in 2021
460M/29 catheters (8.5 and 9.8 cm), 40% of all long peripheral lines that year
76 yrsmedian patient age
9–10 daysmedian dwell, comparable to a 12 cm Seldinger catheter (10 days)
N.S.no significant difference in complications between devices
The team uses ultrasound to match catheter to vein: the 18G 9.8 cm M/29 for veins up to 2 cm deep. They conclude that matching the device to the vein helps preserve the venous system and control device costs.
Experience with long peripheral catheters. PICC team, FH Prague Motol. 7th World Congress on Vascular Access (WoCoVA), 2022.
Background literature
Why longer peripheral lines make sense
Short cannulas fail early
In the French CATHEVAL multicentre study, about half of peripheral catheters failed before the end of treatment. The risk was higher in patients over 70.
Computational modelling shows that the tip angle and the pressure on the vein wall drive mechanical failure. A longer, flexible catheter keeps the tip better centred in a larger vein.
