Advances in research on neuroprotective effects of inert gas / 浙江大学学报·医学版

Inert gas is a group of rare gases with very low activity, their application in medical field has increasingly drawn attentions. It is known that inert gases helium, xenon and argon have protective effects on nervous system and the mechanisms are related to eradicating free radicals, anti-inflammation, suppressing apoptosis, influencing ion channels and so on. Further study on the neuroprotective effect of inert gas will shed light on a new approach to treat neurological diseases.

Heliox y su relación con la fisiología de los flujos respiratorios-aplicación clínica / Heliox and its relation with air way flow physiology: clinical application

Cada día, el hombre se enfrenta a nuevos retos, que lo impulsan a crear y a tratar con nuevas herramientas para mejorar la calidad de vida del paciente en una unidad de cuidado intensivo y en los servicios de urgencias ; puesto que el paciente en estado crítico presenta alteraciones fisiológicas más comúnmente en el sistema respiratorio y cardiovascular, que llevan al deterioro progresivo en su función y a una inadecuada entrega de oxígeno indispensable para el funcionamiento celular. Los últimos estudios traen nuevos tratamientos para enfermedades obstructivas, como la utilización de un gas inerte: el Helio combinado con el oxígeno inhalado, siendo este punto de donde se desprende el interés por saber cómo está siendo aplicado el oxígeno con otros gases, en este caso el Helio. Las enfermedades obstructivas que se presentan en adultos son una condición relativamente frecuente, en donde la obstrucción del aire es irreversible y lentamente progresiva. Al avanzar la enfermedad, hay un aumento de la alteración obstructiva e hiperinsuflación pulmonar con un incremento de la resistencia de la vía aérea.

Alterations of the Ventilation-Perfusion Ratio Measured by Using a Multiple Inert Gas Elimination Technique (MIGET) in One Lung Ventilated Rabbit / 대한마취과학회지

BACKGROUND: In this study, we performed one-lung ventilation (OLV) in rabbits to assess the effects of OLV on the VA/Q ratio and the respiratory physiological changes using MIGET. METHODS: Ten male New Zealand white rabbits, weighing 3-4 kg were selected. To perform MIGET, six inactive gases (SF6, krypton, desflurane, enflurane, diethyl ether, acetone) in 500 ml normal saline were injected intravenously. During two-lung ventilation (TLV), and after OLV for 30 minutes, blood was sampled for blood gas analysis and MIGET, hemodynamic variables were measured. For MIGET, the concentrations of the injected inert gases were measured and converted to retention/excretion data; the VA/Q distribution curve was obtained using a computer. RESULTS: Systolic, mean, and diastolic pulmonary pressures were elevated significantly and pulmonary resistance was doubled (P<0.05) in OLV compared to TLV. Blood pH decreased in OLV. The calculated intrapulmonary shunt was 19% and 52%, TLV and OLV, respectively. The analysis of VA/Q using MIGET showed that the VA/Q distribution curve was wider and that the VA/Q area was larger in normal rabbits. And, that intrapulmonary shunt approximated to 11%. In the case of OLV, a significant increase in shunt was observed but no change in the amount of dead space at distribution area, (log SDQ, log SDV) remained the same, whereas the VA/Q distribution curve shifted toward the right. CONCLUSIONS: OLV in rabbits showed severe hypercapnia and hypoxemia leading to a considerable increase in shunt. Because of the wide range of VA/Q distribution in TLV, no significant changes in respiratory variables were observed during OLV.

Bioterrorismo: onde estamos e para onde vamos? / Bioterrorism: where have we been and were are we going?

Objetivo: revisar os principais aspectos das armas químicas e biológicas que, propositalmente ou por um desastre, poderiam afetar a integridade física de criança e indivíduos em geral. Método: levantamento bibliográfico. Resultados: säo abordados casos de bioterrorismo já perpetrados anteriormente, apresentados os principais microrganismos envolvidos com suas variáveis epidemiológicas, laboratoriais e clínicas, bem como condutas de tratamento e profilaxia. Säo mencionados programas de planejamento de vigilância epidemiológica para os profissionais da Saúde estarem aptos a reconhecer e abordar o tema. Conclusöes: o bioterrorismo deixou de ser uma ameaça e está sendo uma triste realidade atual. Um conhecimento mais amplo sobre o assunto nos prepara melhor para uma possível eventualidade médica.

Measurement of Ventilation-Perfusion Ratio Using Multiple Inert Gas Elimination Technique in the Endotoxin-Induced Septic Rabbit / 대한마취과학회지

BACKGROUND: Endotoxin is a complex lipopolysaccharide molecule situated within the outer membrane of Gram-negative bacteria. Sepsis and acute respiratory failure (ARDS) can be induced by endotoxin. In order to introduce and develop the experimental model of ARDS in sepsis, we induced sepsis with the endotoxin and investigated the change of respiratory pathophysiology during sepsis using a multiple inert gas elimination technique (MIGET). METHODS: Ten New Zealand white rabbits were anesthetized and ventilated with a Harvard apparatus. In 5 rabbits, 2 mg/kg of lipopolysaccaride from E. coli was infused intravenously for 30 min (Toxin group). At 1, 2, 3, and 4 hours after endotoxin infusion, arterial blood gas, and hemodynamic profiles were checked. To perform the MIGET, six inert gases (SF6, krypton, desflurane, enflurane, diethyl ether, acetone) of widely varying solubility were infused peripherally and the excretion and retention data was determined from measurements of inert gas tensions in pulmonary arterial, systemic arterial blood samples and mixd expiratory gas sampling of pre and post septicemia using gas chromatography. We transformed and analysed the data into a V/Q distribution curve to find out the change of V/Q distribution curve. After the experiments, the animals were dissected and the lungs were extracted for wet/dry weight ratio (WW/DW) and microscopic examination. RESULTS: In the Toxin group, the pulmonary arterial pressures were increased and arterial oxygen tensions were decreased after the endotoxin infusion. The lung WW/DW were increased and inflammatory findings were seen in microscopic examination. In the MIGET, shunt, deadspace and log SDQ were increased in the toxin group, though there were wide V/Q distributions in the control group. CONCLUSIONS: We developed a successful endotoxin induced septic animal model, V/Q distribution curve and data using MIGET. The accomplishment of the experiment will not only allow us to better understand pulmonary pathophysiology of endotoxin induced sepsis using MIGET, but it will also contribute to other pulmonary physiology experiments associated with sepsis.

Acute Postoperative Unilateral Pulmonary Edema / 대한마취과학회지

There are many predisposing factors for acute pulmonary edema, namely, left ventricular failure due to cardiac disease or fluid overloading, hypoalbuminemia, pulmonary capillary endothelial damage from bacterial toxins or irritant gases, rare central nervous system injuries pulmonary hyersensitivity reactions, etc. Acute pulmonary edema following operations is a rare complication especially in a patient whose preoperative cardiopulmonary status was within normal limits. We present a case of unilateral pulmonary edema immediately following operation in a 46 year old male patient who had a modified pull-through operation due to tongue cancer and who had no evidence of preoperative cardiopulmonary disorders. The edema was relieved after 9 hours with intensive care of pulmonary edema such as IPPB with Omorphine, diuretics, corticosteroid, asemi-sitting position and frequent tracheal suction.

Measurement of Intraocular Pressure in Gas-filled Human Eye

The injection of various long-lasting inert gases into the vitreous cavity to flatten and support a detached retina is of proven value. Persistence of the inert gas can be advantageous from the point of view of retinal detachment surgery, but they can cause rising of the intraocular pressure(IOP) to a dangerously high level. So an accurate assessment of IOP in gas-filled eye is important. Previous studies documented that Schiotz tonometry significantly underestimates IOP in the gas-filled rabbit eye, and Goldmann tonometry is more accurate. But in the operating room, Schiotz tonometer is the only device to measure the IOP, so the relationship between the true lOP and the IOP measured by the Schiotz tonometry in the human eye is very important. In this study an attempt was made to find the extent of discrepancy between Schiotz and Goldmann tonometry in the assessment of IOP in the gas-filled human eye. We performed pars plana vitrectomy in 12 human eyes and pars plana vitrectomy with lensectomy in 10 human eyes. Postoperatively fluid-gas exchange was done with 15% perfluoropropane gas(C3F8). The IOP and gas level were checked immediately before fluid-gas exchange and 3hr, 6hr, 12hr, 24hr and 72hr after fluid-gas exchange using Schiotz and Goldmann tonometer. The relationship between IOP measured by Schiotz and Goldmann tonometer was suggested. In phakic and aphakic eyes, Schiotz tonometrry always gave a lower value, and the discrepancy seemed to be greater in the eyes filled with more gas.