Electrosurgery and Temperature Increase in Tissue With a Passive Metal Implant.

During monopolar electrosurgery in patients, current paths can be influenced by metal implants, which can cause unintentional tissue heating in proximity to implants. Guidelines concerning electrosurgery and active implants such as pacemakers or implantable cardioverter defibrillators have been published, but most describe interference between electrosurgery and the active implant rather than the risk of unintended tissue heating. Tissue heating in proximity to implants during electrosurgery may cause an increased risk of patient injury.

Measuring Blood Pulse Wave Velocity with Bioimpedance in Different Age Groups.

In this project, we have studied the use of electrical impedance cardiography as a possible method for measuring blood pulse wave velocity, and hence be an aid in the assessment of the degree of arteriosclerosis. Using two different four-electrode setups, we measured the timing of the systolic pulse at two locations, the upper arm and the thorax, and found that the pulse wave velocity was in general higher in older volunteers and furthermore that it was also more heart rate dependent for older subjects. We attribute this to the fact that the degree of arteriosclerosis typically increases with age and that stiffening of the arterial wall will make the arteries less able to comply with increased heart rate (and corresponding blood pressure), without leading to increased pulse wave velocity.

On Sensitivity in Transfer Impedance Measurements.

The term sensitivity is sometimes misused when discussing volume impedance measurements. This is a critique of the name of the quantity sensitivity, as well as pointing out how the term easily can be misinterpreted. To resolve the issue, a shift of focus towards volume impedance density, which is a more useful quantity, is proposed.

Unintentional heating at implants when using electrosurgery.

Electrosurgery is a commonly used device in the operating room, but it has some adverse effects, which are only partly described in literature. Interference issues are well described, but unintended heating in and around implants is not well studied. We simulated different scenarios using a Finite Element Model to investigate unintended heating caused by electrosurgery.