Rui Correia

Anaesthesia induction in small mammal's using an instrumented anaesthetic chamber

Anaesthesia chambers are a method to induce an anaesthetic state to small mammals in laboratory procedures (e.g. mice), when animal handling can alter the outcome of the tests performed due to induced stress [1]. Loss of rightning reflex (LORR) and respiratory rate (RR) are parameters in which the technician relies to evaluate the anaesthesia depth on a visual evaluation. Piezoelectric elements have been successfully presented as a method to monitor vital signs, namely RR, in mice as a non-invasive method [2]. In previous work of this research team, an instrumented chamber with built-in piezoelectric sensors was presented and an accurate measure of the subjects RR was achieved [3]. The aim for this work is to present a preliminary integrated solution for LORR detection and RR monitoring, in order to be implemented in future anaesthesia studies. The tests were conducted on three white NMRI female mices, aging 2 months old and weighing between 38.6 and 40.8g. Each mice was placed inside the chamber and the anaesthetic state was induced at a 5% isoflurane concentration (Isoflo, Esteve Farma Lda., Carnaxide, Portugal) in 100% oxygen at 1 L/min until LORR. Then, the anaesthesia delivery was interrupted, and 100% oxygen at a delivery rate of 2 L/min was provided until recovery of the reflex was observed. One piezoelectric KPSG-100 (30 Vp-p, 1.2±0.2 kHz, Kingstate) sensor was placed underneath the anaesthesia chambers footholds. The sensor was connected to a Kistler 5073-A model charge amplifier (Kistler Corporation, NY, USA). The charge amplifier was configured using Kirstlers ManuWare software. The amplified signal output was then measured using a NI DAQ USB-6251, 16-bit, Multifunction I/O device (National Instruments, Austin, TX, USA) and filtered using a point-to-point 2nd order Butterworth band-pass filter with bandwidth from 0.5 Hz to 5 Hz, in a developed acquisition application in LabVIEW 2013 (National Instruments, USA). LORR detection was achieved through the implementation of an identification algorithm, regarding piezoelectric signal obtained through the mice movement within the chamber or from its breathing cycle. RR was calculated using a peak-to-peak detection algorithm. In the tests performed, it was possible to correctly identify the LORR moment and to achieve RR monitoring during the anaesthesia protocol (Fig 1.). RR variation due to the anaesthesia depth was also noticeable, from a lowering RR right after LORR, to a dissipation of anaesthetic until the moment of recovery. Comparing with the previous results [3], the implementation of the new setup enables a simple LORR detection method with an enhanced RR related signal amplitude (8 mVp-p to 32 mVp-p). Further tests are recommended to observe the system response to mice weight variations and positioning within the chamber. Nonetheless, with the respective validation, the presented system indicates a novel method for anaesthesia related studies and laboratory animal handling.

Remote sensing lab for medical thermal physiological assessment

Medical thermal imaging (MTI) has been used for over five decades, more in medical research than in daily clinical practice. However MTI can provide significant information about the peripheral physiology and thus be of a great help on clinic. Since it was firstly used in medicine, thermal image equipment has evolved, computers have been introduced, and guidelines and standards have been drawn. Even being the third oldest medical imaging modality, further developments are needed to achieve the level of other medical imaging methods, which are wider accepted. In addition, more significant technological development and the integration with the medical information systems still to be done. Other obstacles for the method adoption are the disregard of health professionals, the difficulty on getting adequate training and the large sources of error in a MTI examination. Based in this flaw, this document intends to describe the required developments to address MTI wider adoption and integration. In order to reduce the human factor and the examination environmental errors, the technological improvements needed to allow a remote automated assisted MTI laboratory are outlined. With the adoption and implementation of such suggestion, it will be possible, a wider acceptance of MTI among health professionals, a significant reduction of error sources, appropriate MTI operators training and consequent increase in the credibility and its application in clinical daily practice.

Development of an application for remote syringe pump control in anesthesia infusion

Anesthesia induction is a high risk step in every surgical procedure. However, monitoring and control of anesthesia depth is not fully developed, due to the lack of constant correlation between vital signs and drug infusion. This work proposes a LabVIEW user-friendly application tool to control syringe pumps using serial communication protocol, to enable a better control of the drug infusion process. This application adds several new functionalities, such as alarm detection and handling, faster modification of the infusion rate during anesthetic procedures, data logging, etc. in a simpler way than using the controls on the pump syringe. To make it more flexible, in order to fulfill the requirements of a research application, modular programming was used. This application combines in a single output file, synchronized signals from drug infusion and commands that have been sent. This way it will allow a much faster post-processing of the obtained data, like correlations between induction and depth of anesthesia. For future developments, this application should offer a virtual TCI option towards the control of anesthesia depth. Considering the programming method used, it will be possible to include PK-PD algorithms and link their output to the stored data, while controlling drug infusion process.

Development of new research software for real-time raw electroencephalogram analysis

This work purposes a tool that automatically analyses biomedical signals by applying pre-defined mathematic formulas and algorithms. This tool was developed for allowing a faster EEG signal processing towards the development of an index for monitoring depth of anesthesia in animals, and was tested with preliminary data from 8 dogs. This software automatically synchronizes the EEG signal with the time frames and clinical events desired, and automatically applies the mathematical formulas pre-defined by the operator, displaying the results of the signal processing in real-time. This allows the operator to switch between different EEG algorithms analysis in real-time, and select the algorithm that best fits the stage of anesthesia at each moment. During the development of this software application it was created a color scheme using five different colors based on five different clinical depth of anesthesia planes. This color scheme was linked to a composite permutation entropy index (CPEI) value, allowing a direct correlation between different levels of anesthesia depth and the color grading scale. Although this software was only used for EEG data analysis, it has the potential of being used for analyze other biological signals in real time.

From a wired to a wireless secure EPR: can we re-use existing security solutions?

The use of electronic information systems within the healthcare environment has become essential in order to enable the sharing of patient data. Several constraints during the development of IT solutions often imply that security is an afterthought. The use of wireless technology has been adopted in some healthcare organizations where, the access to patients information and clinical activities becomes ubiquitous and closer to the point of decision. There are, however, specific security problems inherent to wireless technology. The main objective of this study is to design a secure wireless solution from a wired system already in use. This paper shows that it is possible to use the security solutions developed for a wired system as a platform to implement a secure wireless version. This can save time and resources whilst minimizing most security risks inherent to wireless technologies.