Disputas: Anh Tuan Thai Nguyen

25 Oct

Praktisk informasjon

  • Dato: 25. oktober 2016
  • Tid: kl. 10.30 - 16.00
  • Sted: Campus Vestfold, Auditorium Sandefjord

Anh Tuan Thai Nguyen ved Fakultet for teknologi og maritime fag vil forsvare sin avhandling for graden ph.d.: Miniaturization of Circuit Packaging of an Accelerometer Heart Monitoring Device.

Bedømmelseskomité

  • PhD Maaike Op de Beeck Centre for Microsystems Technology, Imec, Belgia
  • Professor Philipp Häfliger, Universitetet i Oslo
  • Professor Erik A. Johannessen, Institutt for mikro- og nanosystemteknologi, HSN

Leder av disputas

Instituttleder Yngvar Berg

Veiledere

  • Førsteamanuensis Kristin Imenes, Institutt for mikro- og nanosystemteknologi, HSN
  • Professor Knut Aasmundtveit, Institutt for mikro- og nanosystemteknologi, HSN
  • Professor Nils Høivik, Institutt for mikro- og nanosystemteknologi, HSN

Program

  • Kl 10.30 Prøveforelesning: «Biocompatible packaging and electrical safety requirements for long term wireless biomedical implants»
  • Kl 13.00 Disputas

Prøveforelesning og disputas er åpen for alle interesserte.

Det vil bli en sammenkomst i personalkantina Grevinnen umiddelbart etter disputasen.

Engelskspråklig sammendrag av avhandlingen

Continuous monitoring of heart activity based on implantable accelerometer devices have proven to be an efficient method that can provide higher sensitivity and specificity than the conventional electrocardiography (ECG). The method can be specified for detection of ischemia on patient who has undergone Coronary Artery Bypass Graft (CABG) surgery. A previous version of the implantable accelerometer device was sutured to the heart surface and had to be removed before closing the patient’s chest since the device dimension was not suitable for closed chest implantation. From a surgical point of view, a heart muscle implantable accelerometer device can properly present the heart motion without interfering with surrounding organs. Such a device can be suitable for both intraoperative and postoperative monitoring procedures. However, a heart muscle implantable device requires miniaturization to ensure minimal tissue trauma and simple implantation procedure.

This study focuses on development of a MEMS-based 3-axis heart muscle implantable accelerometer device. The device is to be implanted into the heart muscle, remain in place after the thorax is closed, and be pulled out though an opening in the chest wall after a few days when intensive care is no longer needed.

Five different versions of a heart muscle implantable accelerometer device have been proposed and developed with regards to the regulatory compliances, clinical demands and requirements of components. These devices were categorized into two main groups built on two types of commercial accelerometer sensors. In comparison to the earlier implantable accelerometer device, the dimensions of these five versions were significantly reduced in steps from 11 mm down to 2.0 mm in the overall diameter.

In the second version device, pacing/sensing functionality similar to a temporary pacing wire was introduced. The study also suggests specific experimental set-ups for qualifying essential safety requirements (e.g. leakage current, tensile strength, flexural endurance, insulation strength) based on the standards and regulation for implantable devices. Tests of complete devices showed leakage currents well below the limit for heart implantable applications. This study also points out that the pulling strength of a device is important for accomplishing both the implantation and removal of the device. Different versions of the devices provided different pulling strengths, which varied from 12N up to 100N. The stability of the devices when implanted into the heart muscle varied between the different versions. Stability depend on the device dimension, encapsulation structure, cable flexibility and the implantation method. Implantation procedures for the different device versions and quality of the acceleration signals was verified and validated in several animal trials and is reported in detail in this study.