title: Laboratory testing of the Pressio intracranial pressure monitor.
abstract: OBJECTIVE
  The Sophysa Pressio (Sophysa Ltd., Orsay, France) is a new intracranial pressure monitoring system. This study aimed to evaluate its accuracy and compare it with the popular Codman intracranial pressure transducer (Codman/Johnson & Johnson, Raynham, MA) in vitro.
  
  
  METHODS
  A computerized rig was used to test the Pressio and Codman transducers simultaneously. Properties that were tested included drift over 7 days, the effect of temperature on drift, frequency response, the accuracy of measurement of static and pulsatile pressures, and connectivity of the system.
  
  
  RESULTS
  Long-term (7 d) relative zero drift was less than 0.05 mmHg. The temperature drift was low (0.3 mmHg/207C). Absolute static accuracy was better than 0.5 mmHg over the range of 0 to 100 mmHg. Pulse waveform accuracy, relative to the Codman transducer, was better than 0.2 mmHg over the range of 1 to 20 mmHg. The frequency bandwidth of the Pressio transducer was 22 Hz. The Pressio monitor can transmit data directly to an external computer without the use of a pressure bridge amplifier.
  
  
  CONCLUSIONS
  The new Pressio transducer proved to be accurate for measuring static and dynamic pressure during in vitro evaluation.
authors.affiliation: UK Shunt Evaluation Laboratory and Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge, England.
authors.forename: David
authors.initials: D
authors.lastname: Allin
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.forename: Zofia
authors.initials: Z
authors.lastname: Czosnyka
mesh_terms: D007427:Intracranial Pressure; D007753:Laboratories; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D012107:Research Design; D014160:Transducers, Pressure