Defense of Mohammed HOJEIJ

Neonatal intensive care units often use multi-infusion: several drugs and nutritional supplies are administered simultaneously via a single catheter, using tubing, valves, filters and manifolds. In this context, flow rates are very low, the therapeutic margin is narrow, and line hydraulics vary constantly (addition of accessories, height changes, manipulations, temporary occlusions). These variations can cause clinically significant transient episodes of under- or overflow, particularly during start-up and setpoint changes.

This thesis proposes an alternative architecture based on pressure regulation actuation rather than syringe pump piston displacement. Fast-acting pressure regulators impose input pressures, while flow sensors close the loop to follow prescribed flow profiles.

This thesis proposes an alternative architecture based on pressure regulation actuation rather than syringe pump piston movement.

The work combines

• a control-oriented hydraulic model, incorporating regular losses in the tubing and, where necessary, singular losses induced by components (valves, filters, connectors),
• a sliding mode control (SMC) to reject bounded disturbances and compensate for model uncertainties,
• an adaptive super-twisting extension (ASTW) to improve transient smoothness and maintain good performance when fluid geometry, flow rates or viscosity vary, without systematic retuning.

An experimental campaign was carried out on two- and four-inlet platforms, with protocols inspired by clinical practice: low and higher regimes, viscosity contrast (water vs. lipid emulsion), simple and complex configurations, and disturbance scenarios (height variations, catheter manipulation, brief occlusion).

The results highlight the benefits of pressure regulation coupled with robust nonlinear control: improved plateau stability, reduced excursions during setpoint changes, limited coupling between channels via the common manifold, and faster return to prescribed values after disturbance. They also show that the explicit integration of singular losses becomes decisive as soon as the line comprises several components.

At the end of the day, the thesis provides a complete framework-multi-inlet platform with pressure regulation, adapted hydraulic modeling and robust/adaptive control laws-opening a path towards more reliable and safer multi-infusion in neonatology.

Prospects include longer durations, a wider range of formulations, and the integration of safety functions (occlusion/disconnection detection, sensor monitoring).

Mrs SOUAD HARMAND University Professor Université Polytechnique Hauts de France, Thesis Director
. M. Michael DEFOORT Professeur des universités Université Polytechnique Hauts de France, Thesis co-director

Mr Safouene OUENZERFI Maître de conférences Université Polytechnique Hauts de France, Examiner
Ms Kaouther MOUSSA Maître de conférences Université Polytechnique Hauts de France, Examiner
Mr Riadh BOUBAKER Research Engineer, Société Nidek, Examiner
Didier SAURY M. Didier SAURY Professeur des universités Directeur Adjoint PPRIME/DFTC, ISAE-ENSMA / Institut PPRIME UPR CNRS 3346, Examiner

.

Mrs Nora ABID University Professor IUSTI Marseille, Rapporteur
. M. Nadhir MESSAI Professeur des universités Université de Reims, Rapporteur

Ms.

Mr Olivier NICOLE Société Vygon, Guest

Neonathalogy, perfusions, fluid mechanics, hydraulic modeling, sliding mode, ASTW
.