Our common understanding for the most important issues in daily life is improvement of health and quality of life in harmony with nature. At the early stage of biomedical engineering (BME) from 1950s to 1970s, it laid on the interdisciplinary region between medicine and engineering. During this period, medicine progressed rapidly through development of clinical examination tests, medical equipments and new drugs. Engineering contributed to medicine through not only providing modern technology but also offering logical thinking way by control and information theories. The growth of medical instrumentation was followed by intensive care units, catheterization laboratory, various medical imaging technologies (ultrasound, X-CT, MRI, SPT and PET) and artificial organs.
As the results of these developments, BME has been established as an independent profession. In Japan, the law of “clinical engineering technician” was enacted in May, 1987 and took effect in the next year. This is a quite unique law which guarantees the technician to manipulate the medical instruments to maintain human blood circulation, respiration and metabolism appropriately, enabling them to participate in the treatment of patients.
Thus, the current BME covers a variety of fields from basic research to clinical medicine. The following areas may have high priorities to promote BME further:
1. functional genomics, physiome
2. cellular and tissue engineering
3. biosensors, intelligent sensors, minutialized sensors
4. medical imaging, nano/micro imaging
5. artificial intelligence, signal interpretation and bioinformatics
6. analysis and support of biological function
7. artificial organs, assist devices and implantable devices
8. medical robotics and support for minimally invasive and/or safety treatment
9. rehabilitation engineering and technical aids for the aged
10. artificial environments (Virtual Reality, Augmented Reality), computational biology
11. BME education and technologies for developing societies
Now that the completion of human genome project was declared, it becomes important to understand the roles of the genes in a living body. Under these circumstance, the “Physiome project” has been commenced in 1997. “Physiome” is a newly coined word: physio= life or nature, ome= as a whole entity. The project is an integrated multi-centric program to design, develop, implement, test and document, archive and disseminate quantitative information of the functional behavior of organelles, cells, tissues, organs and organisms. Identification of each gene and its associated protein forces us to recognize the importance of functions of genes and proteins, and signal networks in organized cells, tissues, organs and organism.
From a therapeutic viewpoint, the results of pharmacological and/or gene interventions, such as desirable effects, adverse reactions and interaction between treatments in patients at risk are not highly predictable. For accurate prediction, a comprehensive grasp of functions of cells, tissues and organs through Physiome is essential.
BME can contribute greatly to gain insights into the functions of living body by systematically integrating among genes, proteins, cells, tissues and organs.

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The world-wide tendency of the resurgence of airborne nosocomial transmission of mycobacterium tuberculosis to patients and health care providers has embarraced intensivists in the last decade. It is not unusual that some pulmonary tuberculosis which is compatible both clinically and radiologically with acute respiratory distress syndrome is not recognized, not diagnosed or even not suspected at the time of ICU admission. Late diagnosis being followed by delayed measures contributes to the persistently high mortality of patients with tuberculosis in ICU. This also increases the risk of disease transmission to health care providers and other patients in the ICU. Emergence of contagious pulmonary tuberculosis in ICU requires urgent measures as well as tuberculosis in community. Complicance with infection control in critical care settings involves the integration of specific policies and procedures into crises-based practice in close collaborations with in-hospital infection control teams and implementation of high-yield triage-screening criteria. The author's advice is that each hospital should develop tuberculosis management policy depending on it's situation. Construction of an isolation compartment is also important to take care of a patient not only with tuberculosis but with other airborne infectious orgasisms.

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We examined the length of stay of 545 patients admitted to the pediatric intensive care unit (PICU), Osaka Medical Center and Research Institute for Maternal and Child Health from January 1, 1997 to December 31, 1999. The mean age of the patients was 2.3 years (range, 0 day-16.8 years). Mean stay in PICU for all patients was 10.6 days (range, 1-203 days), and the total patient days of PICU were 5, 787 days. Patients younger than the age of 28 days (neonates) comprised 19.6% of the PICU patients and occupied 45.1% of the total patient days. Of the neonates, 29 cases (27.1%) were re-admitted to PICU during the same hospitalization. Patients diagnosed with congenital anomalies complicated by severe organ insufficiency, including hypoplastic left heart syndrome, congenital diaphragmatic hernia or omphalocele, needed long PICU stays. Fifty-six percentages of PICU stays of the neonates were not reimbursed by the Japanese health insurance system for the intensive care unit (ICU). Reimbursement for the charges of ICU stay was predetermined to 14 days, however, according to provisional estimates, children and neonates admitted to our PICU required 21 days and 60 days, respectively. We reported the present situation of the PICU in a perinatal center. With the perinatal care progress, neonates will occupy a large fraction of PICU beds. Reform of the health insurance system should be considered to improve pediatric intensive care.

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Pressure support ventilation (PSV) is a mode of partial ventilatory support in which the breathing pattern can be easily affected by breath-by-breath interaction between the patient and a ventilator. Although propofol is advocated for sedation in the ICU, its effect on the breathing pattern during PSV is not well understood.
We studied seven postoperative patients on PSV during propofol sedation (Ramsay score: levels 4-5). Their breathing patterns were analyzed by a desktop computer equipped with a 16-bit AD board to process the flow and pressure signals of the ventilator (Bennet 7200) during and after propofol sedation for more than 30min.
After the termination of propofol sedation, the expiratory time decreased without any changes in the inspiratory time and mean inspiratory flow. This led to increases in respiratory frequency, duty cycle and minute ventilation. Respiratory cycles with a tidal volume of less than 50ml and with twice the mean tidal volume, respectively, appeared at 0% and 0.3% of all respiratory cycles. We concluded that propofol sedation at levels of 4-5 of Ramsay's score is associated with a decrease in minute ventilation due to prolongation of the expiratory time, without apparent changes in inspiratory drive in postoperative patients during PSV, and that it is effective for maintaining patients' adaptation to ventilators under PSV.

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A 48-year-old man in sudden shock and dyspnea was transferred to our hospital. Catecholamines, sodium bicarbonate, and intra-aortic balloon pumping were ineffective to cardiovascular collapse accompanied by metabolic acidosis that was presented on admission and worsened to critical bradycardia and finally to cardiac arrest during coronary angiography. Resuscitation efforts including temporary pacemaker and percutaneous cardiopulmonary support (PCPS) was promptly started and a 100mg of fursultiamine was given intravenously supposing that it was vitamin B₁ deficiency. Metabolic acidosis resolved and hemodynamics stabilized two hours and six hours after the administration respectively. Following administration of fursultiamine at 50mg/day improved his hemodynamics and metabolic acidosis dramatically and the patient was weaned from PCPS on the next day, then discharged, three days after, from the ICU without sequelae. We conclude that an immediate administration of vitamin B₁ is important for patients in whom beriberi heart is suspected.

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A 14-year-old female with severe status asthmaticus was treated with an inhalational anesthetic agent, isoflurane. The treatment resulted in successful remission, therefore it was discontinued after 68hr of inhalation and the total of 97 minimum-alveolar-concentration ·hour of isoflurane administration. However, she remained unconscious even more than 24hr after the cessasion of isoflurane. A computed tomography scan of brain revealed marked hypodensity in bilateral occipital regions, cerebellum, midbrain, and pons. Although these findings were consistent with basilar artery occlusion extensive investigations concerning coagualtion, brain vessels, and heart failed to identify the cause of infarction. We report a case of cerebral infarction and significant neurological deficits which were occured during isoflurane inhalation therapy. The cause is still unknown but we dare to warn that close observation is essential to prolonged anesthesia inhalation for asthmatic patients.

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Although many studies have shown that vasopressin, an antidiuretic hormone, helps to maintain blood pressure in case of cardiopulmonary resuscitation or septic shock, its use in hemorrhagic shock is controversial. We experienced a case of hemorrhagic shock due to rerupture of a common iliac arterial aneurysm in which a single-dose vasopressin improved hemodynamics during the reconstruction surgery. A 60-year-old man suffered rupture of a left common iliac arterial aneurysm and scheduled for an emergency surgery. Suddenly after the induction of anesthesia, his blood pressure fell down to 40/20mmHg and his heart rate increased to 170min_-1. This hypotention was caused by aneurysmal rerupture and hardly responded to the rapid infusion of plasma protein fraction or repeated injections of catecholamines. Then we tried 20 units of vasopressin intravenously. Vasopressin is a strong vasoconstrictor in high doses through V1 receptor of peripheral vessels. One bolus injection of vasopressin raised blood pressure over 80mmHg and decreased heart rate to 140min_-1 and thereafter neither chest compression nor extra bolus injections of catecholamines were needed. A gradual increase of urine output was recognized about one hour later. The replacement of the left common iliac artery with an artificial graft was successful and the patient recovered well without any neurological deficit after the surgery. This case demonstrates the efficacy of intravenous bolus vasopressin to maintain blood pressure in hemorrhagic hypovolemic shock.

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