Evaluation of flow rate accuracy and pressure measurements of testing rig for neurological valve hydrodynamic tests

• Autor(a) principal: Pinto,José Ricardo Camilo
• Data de Publicação: 2014
• Outros Autores: Maset,Angelo Luiz, Andrade,José Ricardo, Mancini,Bruna Monieli, Pereira,Geovânia Marquini Laurentino, Barbosa,Ricardo César, Rollo,João Manuel Domingos de Almeida
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Brasileira de Engenharia Biomédica (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1517-31512014000100005
• topic: Neurological valve; Cerebrospinal fluid; Shunt; Testing rig

INTRODUCTION: Increased production and disorders in the circulation or absorption of cerebrospinal fluid (CSF) leads to increased intracranial pressure and causes a condition called hydrocephalus. The most common treatment for this disorder is the implantation of a ventricle-peritoneal shunt, which consists of the insertion of a ventricular catheter in the cerebral ventricle, a neurological valve for drainage control and a peritoneal catheter that leads the CSF to the abdominal region. The International Organization for Standardization (ISO) 7197 introduced requirements for the design and production of the shunts and neurological valve, including in vitro hydrodynamic tests, which are indispensable for evaluating the performance of the CSF drainage systems. METHODS: A testing rig built in accordance with ISO 7197 was evaluated for the uncertainty of flow and opening and closing pressure measurements, the pressure-flow relationship and reflux neurological valve resistance. The infusion pump and pressure measurement system were evaluated for calibration, hysteresis behavior and stability to determine the experimental uncertainties from hydrodynamic testing of two commercial products. RESULTS: The equipment showed uncertainties of less than 1% in the infusion pump, less than 4% in the pressure sensor and adequate performance for the hydrodynamic tests. CONCLUSION: The hydrodynamic test rig allowed the opening and closing pressures and the resistance to reflux to be obtained, and it also allowed the determination of the pressure and flow rate characteristics of two neurological commercial valves with experimental uncertainties that do not impact the results and the evaluation of in vitro performance of a shunt.