Der Anaesthesist
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Randomized Controlled Trial Clinical Trial
[Increase in interleukin-6 plasma concentrations following hypotensive anesthesia with sodium nitroprusside].
In animal models authors have dealt with the question of whether hypotension alone can cause an acute-phase response even in the absence of marked blood loss and trauma. Sodium nitroprusside (SNP), which was employed in the animal models, is also used to induce hypotension in humans. Since no data are available on human subjects plasma concentrations of interleukin-6 (IL-6), an important mediator of the acute-phase response, were studied in patients during SNP infusion for induction of hypotension. ⋯ The SNP infusion exerted an important additional stimulus for IL-6 release after relatively mild surgical trauma in both groups. This finding is probably due to the liberation of NO from the SNP molecule and an increase in the intracellular concentration of cGMP. The elevation of the plasma catecholamines immediately after SNP administration should also be taken into account, because an augmentation of the cAMP in various cell types has been proven to result in increased release of IL-6.
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The occurrence of severe head injury, isolated or in connection with polytrauma, is a challenge for all physicians working in emergency care at the scene of an accident or afterwards in hospital care. It is an advantage to have a basic knowledge of neurological assessment. The Glasgow Coma Scale is widely used in this context; we refer to mild, moderate, and severe injuries. ⋯ It has not yet been possible to show that using corticosteroids is definitely beneficial in human brain trauma; there may be a positive effect in connection with spinal trauma. New therapies are being investigated, such as increasing CPP, administering AMPA/NMDA-antagonists, 21-aminosteroids, or hypertonic-hyperoncotic solutions. However, they have not as yet been proven effective for general clinical use or clinical use et al.
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Gamma-hydroxybutyric acid (GHB) is a naturally occurring transmitter in the mammalian brain, related to sleep regulation and possibly to energy balance in diving or hibernating animals. It has been used for almost 35 years as an intravenous agent for induction of anaesthesia and for long-term sedation. Its convincing pharmacological properties, without serious adverse effects on circulation or respiration, are compromised by its unpredictable duration of action. ⋯ We conclude that animal data may not apply to the use of GHB in humans, provided the dose is limited to the clinical needs. GHB is used in clinical practice in doses twice as high, or even higher, than the one we use for induction, without obvious side effects. However, the suppression of theta rhythm we observed in about half of the patients studied may indicate that even less than 50 mg/kg BW might be sufficient for adequate sedation.
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The arteriovenous oxygen content difference (avDO2) of the brain is dependent on O2 consumption (CM-RO2) and cerebral blood flow (CBF). With unchanging arterial O2 content, avDO2 is inversely related to cerebral venous O2 saturation (SO2). Measurement of SO2 in the jugular bulb not only provides information about the O2 balance of the brain, but may give an important estimation of CBF if a clinically useful correlation is proven. ⋯ In this clinical study, a close relationship between cerebral venous SO2 and CBF was not found. This was primarily due to the high variability of cerebral O2 uptake. Changes in cerebral venous SO2 may therefore not be used as an estimate of perioperative changes in CBF.
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The physiological pattern of regional pulmonary blood flow is mainly determined by the relationship of pulmonary arterial, venous, and alveolar pressures. Changes in alveolar pressure and pulmonary geometry may therefore be expected to influence regional perfusion, which is a key determinant of pulmonary gas exchange. Unilateral thoracotomy is usually performed with the patient in the lateral decubitus position. ⋯ Apart from a radial perfusion gradient in the right lower lobe during 2LVC and 2LVT, no isogravitational Qr gradients were observed. CONCLUSION. We conclude that controlled mechanical ventilation in the lateral decubitus position causes only minor changes in vertical blood flow distribution.