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#16
28.06.2005, 05:04
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Öèòàòà:
Êëèíè÷åñêèå èñïûòàíèÿ, äîêàçàòåëüíîñòü â Ðîññèè ôèêöèÿ. Äåíåã äàëè, ïðîïèàðèëè è âñÿ ïðîáëåìà. Áëèí 
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#17
29.06.2005, 14:32
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Öèòàòà:
Òóò ìû âïåðåäè ïëàíåòû âñåé, ïîñêîëüêó êñåíîí çàðåãèñòðèðîâàí â Ðîññèè â êà÷åñòâå ìåäèöèíñêîãî ãàçà. Ïðîáóéòå, äåðçàéòå, ïèøèòå â ïðåñòèæíûå æóðíàëû.
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#18
29.06.2005, 14:35
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Öèòàòà:
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#19
29.06.2005, 14:39
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Öèòàòà:
Åñëè áû ê ýòîìó â íàøåé ñòðàíå øèðîêî èñïîëüçîâàëàñü òåõíèêà íèçêîïîòî÷íîé àíåñòåçèè - öåíû áû íàì íå áûëî! 
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#20
08.11.2005, 16:31
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Êîíôåðåíöèÿ â äåêàáðå
Íàøåë â èíòåðíåòå èíôîðìàöèþ î êîíôåðåíöèè ïî ìåäèöèíñêîìó êñåíîíó
[Ññûëêè äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì ], êîìó èíòåðåñíî ìîãóò ïîñåòèòü. ß ïîéäó. Âñåì óäà÷è.
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#21
08.11.2005, 20:11
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Öèòàòà:
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Êîíå÷íî
À êàê òàì â Øòàòàõ?
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#24
08.11.2005, 22:17
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Öèòàòà:
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#25
09.11.2005, 13:16
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Äóéòå â òðóáêó áîëüíîé
Öèòàòà:
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#26
14.11.2005, 13:13
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Öèòàòà:
[Ññûëêè äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì ]
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#27
14.11.2005, 14:29
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Öèòàòà:
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#28
15.11.2005, 05:02
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Öèòàòà:
Àâòîðû:M.Coburn.O.Kunitz,J.-H.Baumert,K.Hecker,R.Rossaint (University Hospital of Aachen,Germany.Aâòîðû ïðîâåëè èññëåäîâàíèå íà 80 ïàöèåíòàõ ñ èñïîëüçîâàíèåì êñåíîíîâîé àíåñòåçèè.Êîìïàíèÿ -ïðîèçâîäèòåëü ìåäèöèíñêîãî êñåíîíà -Messer-Grieshheim GmbH.Xenon áûë èñïîëüçîâàí ïî çàêðûòîìó êîíòóðó àíåñòåçèîëîãè÷åñêîãî àïïàðàòà (machine) Physioflex,Draeger ñ ìîäèôèöèðîâàííûì software äëÿ óìåíüøåíèÿ ðàñõîäà êñåíîíà ïðè óñëîâèè ìèíèìàëüíîãî ïîòîêà ñâåæåãî ãàçà.Êîíöåíòðàöèÿ êñåíîíà âî âäûõàåìîé ñìåñè îïðåäåëÿëàñü ñ ïîìîùüþ óñòðîéñòâà,îñíîâàííîãî íà îïðåäåëåíèè òåïëîïðîâîäíîñòè ãàçîâ âäûõàåìîé ñìåñè.Òî÷íîñòü îïåäåëåíèÿ +/- 3 îáüåìíûõ ïðîöåíòà.Ïîñêîëüêó êñåíîí-èíåðòíûé ãàç,òî îáû÷íûå ãàçîàíàëèçàòîðû,èñïîëüçóþùèå ïîëÿðèçóþùèå ñâîéñòâà ìîëåêóë âñåõ äðóãèõ ãàçîâ(êèñëîðîäà,óãëåêèñëîãî ãàçà,çàêèñè àçîòà è èñïàðÿåìûõ èíãàëÿöèîííûõ àíåñòåòèêîâ)äëÿ äåòåêöèè èõ êîíöåíòðàöèè,íå â ñîñòîÿíèè îïðåäåëèòü íàëè÷èå êñåíîíà âî âäûõàåìîû/âûäûõàåìîé ñìåñè.Ïîýòîìó,îñíîâíûì óñëîâèåì àäåêâàòíîãî îïðåäåëåíèÿ êîíöåíòðàöèè ñ ïîìîùüþ òåðìîêîíäóêòèâíîãî äàò÷èêà ÿâëÿåòñÿ äåíèòîãåíèçàöèÿ äûõàòåëüíîãî êîíòóðà,ïóòåì ïðåîêñèãåíàöèè ïàöèåíòà äëÿ óäàëåíèÿ àçîòà âîçäóõà.Èíà÷å äàò÷èê áóäåò îøèáî÷íî îïðåäåëÿòü àçîò êàê êñåíîí. Àíåñòåçèÿ ïîääåðæèâàëàñü ñìåñüþ 60% êñåíîíà â êèñëîðîäå. Àâòîðû óòâåðæäàþò,÷òî ðåçóëüòàòû êñåíîíîâîé àíåñòåçèè íå îòëè÷àþòñÿ ïî ñâîèì ïîñëåîïåðàöîííûì ýôôåêòàì îò ïðîïîôîëîâî/ðåìèôåíòàíèëîâîé àíåñòåçèè.
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#29
15.11.2005, 05:18
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#30
15.11.2005, 06:53
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Öèòàòà:
Online Early doi:10.1111/j.1365-2044.2005.04379.x Volume 0 Issue 0 APPARATUS Xenon measurement in breathing systems: a comparison of ultrasonic and thermal conductivity methods R. King1, M. Bretland1, A. Wilkes2 and J. Dingley1 Summary Xenon is an anaesthetic and possibly neuroprotective gas that is impossible to measure using conventional anaesthetic gas analysers. We compared the performance of two commissioned xenon analysers using ultrasonic and thermal conductivity principles against a reference method of laser refractometry. An experimental gas circuit was constructed and xenon concentrations compared over a range of 0–100% in oxygen. Eighty-two paired measurements were made comparing the experimental methods with laser refractometry. The ultrasonic method displayed good agreement with laser refractometry, with a mean difference of − 0.74% and two standard deviation limits of agreement of + 1.08% to − 2.56%. The agreement between laser refractometry and thermal conductivity was poor, the mean difference being − 5.37%, with two standard deviation limits of agreement of + 0.6% to − 11.3%. The ultrasonic method for measuring xenon concentrations can be used in breathing circuits. The thermal conductivity instrument may need further development -------------------------------------------------------------------------------- Recent developments Xenon is Greek for stranger. It was discover in 1898 and found to be the only noble gas to be anaesthetic under normobaric conditions. Xenon is extremely scarce with an average room containing only 4ml. Manufacture is by fractional distillation of air and costs 2000 times more than N2O. Commercial uses include lasers, high intensity lamps, flash bulbs, aerospace, X-ray tubes and medicine. Physical properties Colourless, odourless, tasteless. Monatomic gas, atomic number = 54, molecular weight = 131,3 Gas undr normal temperature and pressure 9 stable isotopes. Freezing point -111,9oC, Boiling point -108,1oC. 4 times more dense than air. Nonflammable and will not support combustion. Diffuses freely through rubber and silicone components. Anaesthetic agent First used in 1951 by Cullen on an 81yr old man having an orchidectomy.. Very close to the ‘ideal agent’ The very large electron shell of xenon ca be distorted and polarised by nearby molecules, creating a dipole. Xenon inhibits the plasma membrane Ca2+ pump, altering excitability. It inhibits the nociceptive responsiveness of spinal dorsal horn neurons. MAC = 71%. (With more widespread usage the Russians have noticed the MAC to be closer to 60%) Minimal haemodynamic effects. Lowest blood/gas partition coefficient = 0,115 of currently available inhalational agents. Low oil/water partition co-efficient of 20. Rapid induction and eduction regardless of duration of administration 4 stages of anaesthesia noted with 70% Xenon/ 30% oxygen. Whole body paraesthesia & hypo-algesia. Euphoria & increased psychomotor activity. Analgesia with partial amnesia (after 3-4min). Surgical anaesthesia with a degree of muscle relaxation. Equivalent analgesia when compared with equipotent doses of N2O The analgesia produced by both gases is not reversible by naloxone. No occupational/ environmental disadvantages. Specific effects on the body Respiratory Central depression causes a decrease in respiratory rate with a compensatory increase in tidal volume and can progress to apnoea Higher density and viscosity (compared with oxygen, air and N2O) theoretically makes xenon more likely to increase airway resistance. Clinically the airway resistance is slightly less than that seen with N2O and it can be used safely in lung disease Diffusion hypoxia is very mild as the blood/gas partition of Nitrogen (0.014) is only 10 times less than that of Xenon (0.14) as opposed to the almost 40 times less than Nitrous Oxide (0.47) Cardiovascular No inhibitory effects on cardiac ion channels i.e. calcium, sodium and inward potassium channels. No significant change in contractility, blood pressure and systemic resistance. Some reports of decrease in heart rate with variability in rhythm. No sensitisation of the myocardium to adrenaline May attenuate the myocardial depressant effects of isoflurane. In an animal study, xenon anaesthesia produced the highest regional blood flow to brain, liver, kidneys and GIT. The control groups were 1% halothane in Nitrous oxide and thiopentone with fentanyl. Central nervous system Xenon increases cerebral blood flow, increases intracranial pressure and decreases cerebral perfusion pressure in acute head injury patients. This is not associated with cerebral oligaemia or ischaemia. This increase in cerebral blood flow is reveresed by mild hyperventilation At present it is not recommended for neurosurgery. Renal No data available. Endocrine/neurohumoral Attenuates surgical stress due to analgesia. Does not have any short or long term cortisol suppresion effects. Toxicity Platelet aggregation potentiated at 2atm (relevant to deep-sea divers). No reported haematological toxicity. Malignant hyperthermia Seems not to trigger malignant hyperthermia. Metabolism and elimination Unlikely to be involved in any biochemical events in the body. Eliminated via the lungs. Under special conditions xenon is capable of forming compounds with very reactive elements e.g. clathrates, fluorides & chlorides Potential ways to make xenon anaesthesia economically acceptable. Decreasing manufacturing costs. This is only practical in large air separation plants. Current price is 10 US$/ litre Manufacture will increase as aerospace applications grow, but as this xenon is then lost to the atmosphere this will not contribute to decreasing the cost. Use in a fully closed breathing system Use of semiclosed systems (facemasks/LMA/spontaneous breathing) cost £1200/hr. Very low flow e.g. 0,3 l/min will cost £160-180/hr. Fully closed automated systems are available that are suitable for xenon anaesthesia Gas piston circle physioflex device Balanced circle systems. Circle priming Recycling devices are the only way of guaranteeing the availability of a sufficient amount of xenon for routine clinical use. Gas analysis Xenon can be measured with mass spectrometry, piezoelectric absorption, thermal conductivity and ultra-sound. Practical use Nitrogen must be washed out by giving a high flow of pure oxygen for at least 5 minutes Normal induction and muscle relaxation After intubation connect the patient to an appropriate anaesthesia delivery system The hypnotic concentration of 40-45% is achieved after 1.5min The anaesthetic concentration of 60-70% takes approximately 8 minutes. Summary Colourless and odourless gas with no irritation to the respiratory tract. Well tolerated with gas induction Low blood/gas and oil/water partition co-efficients allowing rapid induction and eduction Produces unconsciousness with analgesia and a degree of muscle relaxation MAC of 60-70% allows a reasonable inspired oxygen concentration It does cause respiratory depression, to the point of apnoea. It is cardiac stable. Not metabolised in the body and is eliminated rapidly and completely via the lungs. It is non toxic and is not associated with allergic reactions Stable in storage, no interaction with anaesthesia circuits or soda lime. Should not be used with rubber anaesthesia circuits as there is a high loss through the rubber Non flammable Expensive - Routine usage will only be possible with a closed circuit delivery system that recycles xenon. Owing to environmental concerns there may be no alternative but to use xenon even if it incurs an increase in cost.
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