A. Rebel

Local cerebral blood flow, Local cerebral glucose utilization, and flow-metabolism coupling during sevoflurane versus isoflurane anesthesia in rats

Background Compared to isoflurane, knowledge of local cerebral glucose utilization (LCGU) and local cerebral blood flow (LCBF) during sevoflurane anesthesia is limited. Methods LCGU, LCBF, and their overall means were measured in Sprague‐Dawley rats (8 groups, n = 6 each) during sevoflurane and isoflurane anesthesia, 1 and 2 MAC, and in conscious control animals (2 groups, n = 6 each) using the autoradiographic 2‐[(14) C]deoxy‐D‐glucose and 4‐iodo‐N‐methyl‐[(14) C]antipyrine methods. Results During anesthesia, mean cerebral glucose utilization was decreased: control, 56 +/− 5 [micro sign]mol [middle dot] 100 g‐1 [middle dot]‐1; 1 MAC isoflurane, 32 +/− 4 [micro sign]mol [middle dot] 100 g‐1 [middle dot] min‐1 (‐43%); 1 MAC sevoflurane, 37 +/− 5 [micro sign]mol [middle dot] 100 g‐1 [middle dot] min‐1 (‐34%); 2 MAC isoflurane, 23 +/− 3 [micro sign]mol [middle dot] 100 g‐1 [middle dot] min‐1 (‐58%); 2 MAC sevoflurane, 23 +/− 5 [micro sign]mol [middle dot] 100 g‐1 [middle dot] min‐1 (‐59%). Local analysis showed a reduction in LCGU in the majority of the 40 brain regions analyzed. Mean cerebral blood flow was increased as follows: control, 93 +/− 8 ml [middle dot] 100 g‐1 [middle dot] min‐1; 1 MAC isoflurane, 119 +/− 19 ml [middle dot] 100 g‐1 [middle dot] min‐1 (+28%); 1 MAC sevoflurane, 104 +/− 15 ml [middle dot] 100 g‐1 [middle dot] min‐1 (+12%); 2 MAC isoflurane, 149 +/− 17 ml [middle dot] 100 g‐1 [middle dot] min‐1 (+60%); 2 MAC sevoflurane, 118 +/− 21 ml [middle dot] 100 g‐1 [middle dot] min‐1 (+27%). LCBF was increased in most brain structures investigated. Correlation coefficients obtained for the relationship between LCGU and LCBF were as follows: control, 0.93; 1 MAC isoflurane, 0.89; 2 MAC isoflurane, 0.71; 1 MAC sevoflurane, 0.83; 2 MAC sevoflurane, 0.59). Conclusion Mean and local cerebral blood flows were lower during sevoflurane than during isoflurane anesthesia. This difference cannot be explained by differing changes in glucose utilization because glucose utilization was decreased to the same extent in both groups.

Local coupling of cerebral blood flow to cerebral glucose metabolism during inhalational anesthesia in rats: desflurane versus isoflurane.

BACKGROUNDnIt is not known whether the effects of desflurane on local cerebral glucose utilization (LCGU) and local cerebral blood flow (LCBF) are different from those of other volatile anesthetics.nnnMETHODSnUsing the autoradiographic iodoantipyrine and deoxyglucose methods, LCGU, LCBF, and their overall means were measured in 60 Sprague-Dawley rats (10 groups, n = 6 each) during desflurane and isoflurane anesthesia and in conscious controls.nnnRESULTSnDuring anesthesia, mean cerebral glucose utilization was decreased compared with conscious controls: 1 minimum alveolar concentration (MAC) desflurane: -52%; 1 MAC isoflurane: -44%; 2 MAC desflurane: -62%; and 2 MAC isoflurane: -60%. Local analysis showed a reduction of LCGU in the majority of the 40 brain regions analyzed. Mean cerebral blood flow was increased: 1 MAC desflurane: +40%; 1 MAC isoflurane: +43%; 2 MAC desflurane and 2 MAC isoflurane: +70%. LCBF was increased in all brain structures investigated except in the auditory cortex. No significant differences (P < 0.05) could be observed between both anesthetics for mean values of cerebral glucose use and blood flow. Correlation coefficients obtained for the relation between LCGU and LCBF were as follows: controls: 0.95; 1 MAC desflurane: 0.89; 2 MAC desflurane: 0.60; 1 MAC isoflurane: 0.87; and 2 MAC isoflurane: 0.68.nnnCONCLUSIONnDifferences in the physicochemical properties of desflurane compared with isoflurane are not associated with major differences in the effects of both volatile anesthetics on cerebral glucose utilization, blood flow, and the coupling between LCBF and LCGU.

Neue Airbag-assoziierte Verletzungsmuster nach Verkehrsunfällen

ZusammenfassungExperimentelle Untersuchungen haben gezeigt, daß bei Verkehrsunfällen mit Frontalaufprall neue Rückhaltesysteme wie der Airbag das Auftreten vital bedrohlicher Verletzungen signifikant reduzieren. Ob der Airbag mit besonderen Verletzungsmustern in Verbindung gebracht werden kann, ist bislang noch nicht eindeutig belegt. Systematisch sind nach Aufarbeitung von Verkehrsunfällen mit Airbagbeteiligung, die Verletzungsmuster und der jeweilige klinische Verlauf von zwei Verkehrsunfällen mit Airbag untersucht worden. In einem Fall verhinderte das Aigbagsystem bei Frontalkollision bei einer Aufprallgeschwindigkeit von 100u2005km/h vital bedrohlich Verletzungen. In einem anderen Fall wurden zunächst nur geringgradige Gesichtsverletzungen nach dem Verkehrsunfall diagnostiziert; mit einer zeitlichen Verzögerung von 3u2005h trat hämodynamische Instabilität auf, die durch einen traumatischen Abriß der V. azygos bedingt war. Die Analyse der dargestellten Fälle zeigt neben den offensichtlichen Vorteilen des Airbagsystems Verletzungsmuster, die mit diesem Rückhaltesystem in Verbindung gebracht werden können. Das Airbag-assoziierte Verletzungsausmaß kann nach unseren dargestellten Ergebnissen nicht mit den üblichen klinischen Kriterien abgeschätzt werden. Es wird empfohlen, daß zunächst jeder Airbag-Verunfallte besonders aufmerksam untersucht und einer klinischen Überwachung zugeführt wird.AbstractExperimental studies have shown that in traffic accidents with frontal impact the new airbag system can significantly reduce the incidence of severe injuries and fatal outcome. The question of whether the airbag itself induces specific patterns of injury needs further investigation. Two cases of traffic accidents with airbag protection are presented here. The first case report clearly shows the life-saving and injury-reducing effect of the airbag system in a traffic accident with frontal impact at 100u2005km/h. In the second case only minor injuries of the face were diagnosed initially. Hemodynamic instability occurred after 3u2005h of hospitalization due to rupture of the azygos vein. Analysis of the presented cases shows that, besides the well-known benefits, there are certain injury patterns that seem to be related to the use of airbags. These have not been described before. It is concluded that patients who were involved in traffic accidents with airbag deployment have to be hospitalized and followed up carefully over time, even though they are initially stable, as potentially fatal sequelae of deceleration trauma can occur later. In our opinion it is not possible to estimate the severity of airbag-associated injuries with conventional methods.

Zerebrale Effekte von Perfluorcarbonen

ZusammenfassungPerfluorcarbone (PFC) sind künstliche Sauerstoffträger, die ursprünglich als Blutersatzstoffe entwickelt wurden. Auf Grund ihrer spezifischen Eigenschaften ist darüber hinaus ihr Einsatz bei ischämischen Perfusionsstörungen von potentiellen Nutzen. Neuere Perfluorcarbonpräparationen verfügen über eine höhere Sauerstofftransportkapazität und sind mit weniger Nebenwirkungen behaftet als die PFC der ersten Generation. Ältere und neuere PFC-Emulsionen, die für die intravaskuläre Applikation geeignet sind, wurden und werden im Tierversuch für den Einsatz in ischämischen Gebieten des Herzens und des Gehirns untersucht. In dieser Arbeit werden präklinische Studien bei Infarkten und Reperfusionsschaden beschrieben und potentielle Nutzungsmöglichkeiten dieser Substanzgruppe für diese Indikationsstellung diskutiert.SummaryFor the ussage as blood substitutes perfluorocarbons (PFC) have been developed as artificial oxygen carriers. In addition they may have potency for protective use in ischemic tissue. Formulation improvement achieved higher oxygen carrying capacity and better compatibility than the first generation of PFC. Preclinical studies have been performed in animal heart and brain. Former and progressed emulsification for intravascular use have been investigated for infarction and reperfusion injury. This investigations are reviewed and the potencies for the use of PFC in neurology, neurosurgery, diagnostics today and in the future are emphasized.