Medical & biological engineering & computing
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Med Biol Eng Comput · Jul 2010
EditorialEvidence-based approach to the maintenance of laboratory and medical equipment in resource-poor settings.
Much of the laboratory and medical equipment in resource-poor settings is out-of-service. The most commonly cited reasons are (1) a lack of spare parts and (2) a lack of highly trained technicians. However, there is little data to support these hypotheses, or to generate evidence-based solutions to the problem. ⋯ We conclude that a great majority of laboratory and medical equipment can be put back into service without importing spare parts and using only basic knowledge. Capacity building in resource-poor settings should first focus on a limited set of knowledge; a body of knowledge that we call the biomedical technician's assistant (BTA). This data set suggests that a supported BTA could place 66% of the out-of-service laboratory and medical equipment in their hospital back into service.
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Med Biol Eng Comput · May 2010
A technique based on laser Doppler flowmetry and photoplethysmography for simultaneously monitoring blood flow at different tissue depths.
The aim of this study was to validate a non-invasive optical probe for simultaneous blood flow measurement at different vascular depths combining three photoplethysmography (PPG) channels and laser Doppler flowmeter (LDF). Wavelengths of the PPG were near-infrared 810 nm with source-to-detector separation of 10 and 25 mm, and green 560 nm with source-to-detector separation of 4 mm. The probe is intended for clinical studies of pressure ulcer aetiology. ⋯ Blood flows at rest and post-exercise were compared. It can be concluded that this probe is useful as a tool for discriminating between blood flows at different vascular tissue depths. The vascular depths reached for the different channels in this study were at least 23 mm for the near-infrared PPG channel (source-to-detector separation 25 mm), 10-15 mm for the near-infrared PPG channel (separation 10 mm), and shallower than 4 mm for both the green PPG channel (separation 4 mm) and LDF.
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Med Biol Eng Comput · Apr 2010
A novel online method to monitor autonomic nervous activity based on arterial wall impedance and heart rate variability.
This paper proposes a new method of evaluating autonomic nervous activity using the mechanical impedance of arterial walls and heart rate variability. The cardiovascular system is indispensable to life maintenance functions, and homeostasis is maintained by the autonomic nervous system. ⋯ In this paper, we monitored autonomic nervous system activity using the proposed system during endoscopic transthoracic sympathetic block surgery in eight patients with hyperhidrosis. The experimental results indicated that the proposed system can be used to estimate autonomic nervous activity in response to events during operations.
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Med Biol Eng Comput · Feb 2010
Theoretical evaluation of a simple cooling pad for inducing hypothermia in the spinal cord following traumatic injury.
The Pennes bioheat equation and finite element method (FEM) are used to solve for the temperature distributions in the spinal cord and cerebrospinal fluid (CSF) during 30 min of cooling for spinal cord injury (SCI) patients. The average CSF and spinal cord temperatures are reduced by 3.48 and 2.72 degrees C, respectively. The 100-mm wide pad provides the desired cooling and uses the least amount of material. ⋯ The temperature decrease in the spinal cord is more than doubled when the temperature at the back of the torso is lowered from 20 to 0 degrees C. Spinal cord ischemia, often observed after traumatic spinal cord injury, promotes cooling penetration. The proposed technique can reduce the spinal cord temperature by 2 degrees C within 30 min and may be a feasible treatment for traumatic SCI.
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Med Biol Eng Comput · Feb 2010
Increase in intrathoracic volume in pectus excavatum patients after the Nuss procedure.
In this study, we present finite element analysis models to calculate the increase in intrathoracic volume of pectus excavatum patients after the Nuss procedure. One virtue of our approach is that the measurement of the intrathoracic volume has no time difference and is not affected by postoperative pain, which cannot be achieved with a 2-year difference between pre- and postoperative pulmonary function testing or any other clinical method. ⋯ The increment curve was patient-dependent, although the increment behavior was similar among the six patients examined. The curve of the increase became flat when the elevating force exceeded 80 N or the displacement of the lower sternal end exceeded 2.6 cm in half of our cases.