From the first pacemaker implant in 1958, numerous engineering and medical activities for implantable medical device development have faced challenges in materials, battery power, functionality, electrical power consumption, size shrinkage, system delivery, and wireless communication. With explosive advances in scientific and engineering technology, many implantable medical devices such as the pacemaker, cochlear implant, and real-time blood pressure sensors have been developed and improved. This trend of progress in medical devices will continue because of the coming super-aged society, which will result in more consumers for the devices. The inner body is a special space filled with electrical, chemical, mechanical, and marine-salted reactions. Therefore, electrical connectivity and communication, corrosion, robustness, and hermeticity are key factors to be considered during the development stage. The main participants in the development stage are the user, the medical staff, and the engineer or technician. Thus, there are three different viewpoints in the development of implantable devices. In this review paper, considerations in the development of implantable medical devices will be presented from the viewpoint of an engineering mind.
Biocompatible Materials ; Biomedical Engineering ; Blood Pressure ; Cochlear Implants ; Corrosion ; Electronics, Medical ; Humans ; Medical Staff ; Micro-Electrical-Mechanical Systems

BACKGROUND/AIMS: Bile acid is an important luminal factor that affects gastrointestinal motility and secretion. We investigated the effect of bile acid on secretion in the proximal and distal rat colon and coordination of bowel movements in the guinea pig colon. METHODS: The short-circuit current from the mucosal strip of the proximal and distal rat colon was compared under control conditions after induction of secretion with deoxycholic acid (DCA) as well as after inhibition of secretion with indomethacin, 1,2-bis (o-aminophenoxy) ethane-N,N,N′,N′-tetra-acetic acid (an intracellular calcium chelator; BAPTA), and tetrodotoxin (TTX) using an Ussing chamber. Colonic pressure patterns were also evaluated in the extracted guinea pig colon during resting, DCA stimulation, and inhibition by TTX using a newly developed pressure-sensing artificial stool. RESULTS: The secretory response in the distal colon was proportionate to the concentration of DCA. Also, indomethacin, BAPTA, and TTX inhibited chloride secretion in response to DCA significantly (P < 0.05). However, these changes were not detected in the proximal colon. When we evaluated motility, we found that DCA induced an increase in luminal pressure at the proximal, middle, and distal sensors of an artificial stool simultaneously during the non-peristaltic period (P < 0.05). In contrast, during peristalsis, DCA induced an increase in luminal pressure at the proximal sensor and a decrease in pressure at the middle and distal sensors of the artificial stool (P < 0.05). CONCLUSIONS: DCA induced a clear segmental difference in electrogenic secretion. Also, DCA induced a more powerful peristaltic contraction only during the peristaltic period.
Animals ; Bile ; Calcium ; Colon ; Deoxycholic Acid* ; Gastrointestinal Motility ; Guinea Pigs* ; Guinea* ; Indomethacin ; Intestine, Large* ; Peristalsis ; Phenobarbital ; Rats* ; Tetrodotoxin

The loss of urinary bladder control/sensation, also known as urinary incontinence (UI), is a common clinical problem in autistic children, diabetics, and the elderly. UI not only causes discomfort for patients but may also lead to kidney failure, infections, and even death. The increase of bladder urine volume/pressure above normal ranges without sensation of UI patients necessitates the need for bladder sensors. Currently, a catheter-based sensor is introduced directly through the urethra into the bladder to measure pressure variations. Unfortunately, this method is inaccurate because measurement is affected by disturbances in catheter lines as well as delays in response time owing to the inertia of urine inside the bladder. Moreover, this technique can cause infection during prolonged use; hence, it is only suitable for short-term measurement. Development of discrete wireless implantable sensors to measure bladder volume/pressure would allow for long-term monitoring within the bladder, while maintaining the patient's quality of life. With the recent advances in microfabrication, the size of implantable bladder sensors has been significantly reduced. However, microfabricated sensors face hostility from the bladder environment and require surgical intervention for implantation inside the bladder. Here, we explore the various types of implantable bladder sensors and current efforts to solve issues like hermeticity, biocompatibility, drift, telemetry, power, and compatibility issues with popular imaging tools such as computed tomography and magnetic resonance imaging. We also discuss some possible improvements/emerging trends in the design of an implantable bladder sensor.
Aged ; Biocompatible Materials ; Catheters ; Child ; Hostility ; Humans ; Magnetic Resonance Imaging ; Microtechnology ; Quality of Life ; Reaction Time ; Reference Values ; Renal Insufficiency ; Sensation ; Telemetry ; Urethra ; Urinary Bladder* ; Urinary Incontinence

These are natural inhibitors of coagulation, and deficiencies of any of these factors is referred to as thrombophilia. The identified main causes of thrombophilia are deficiencies of antithrombin III, protein C, or protein S, resistance to actived protein C associated with Factor V Leiden mutation, and inherited hyperhomocystinemia. Inherited and acquired thrombophilias may also contribute to pathophysiological processes involved in recurrent pregnancy loss, fetal death, intrauterine growth restriction, placental abruption, placental infarction, and pre-eclampsia. Various therapeutic protocols with low-molecular-weight heparin (LMWH) were used. because it is associated with a low incidence of osteoporosis and thrombocytopenia. We experienced the two cases of successful deliveries by Cesarean section following a successful pregnancy maintenance in thrombophilia. we administered LMWH to prevent thromboembolism. one patient was the primi-gravidarum, with inherited thrombophilia, who has the familial history of pulmonary embolism and deep vein thrombosis. the other was the multi-gravidarum, with acquired thrombophilia, who has the past medical history of pulmonary embolism.
Abruptio Placentae ; Antithrombin III ; Cesarean Section ; Factor V ; Female ; Fetal Death ; Heparin, Low-Molecular-Weight ; Humans ; Incidence ; Infarction ; Osteoporosis ; Pre-Eclampsia ; Pregnancy Maintenance ; Pregnancy* ; Protein C ; Protein S ; Pulmonary Embolism ; Thrombocytopenia ; Thromboembolism ; Thrombophilia* ; Venous Thrombosis

The typical radiographic findings of pulmonary edema from the increased hydrostatic pressure shows centrally localized consolidation, which is known as a "butterfly or bat's wing" pattern. These terms describe the anatomic distribution of edema that uniformly involve the hilum and medulla of the lung but not the peripheral region of the lung parenchyma (cortex). We present a case of butterfly wing-like pulmonary edema on a chest radiograph by mitral regurgitation due to an idiopathic chordal rupture.
Butterflies ; Chordae Tendineae ; Edema ; Hydrostatic Pressure ; Lung ; Mitral Valve Insufficiency ; Pulmonary Edema* ; Radiography, Thoracic ; Rupture*