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This paper presents a concept for detection of venous air emboli inside the superior vena cava using a central venous catheter with integrated Doppler ultrasound transducer installed on the tip. Several Doppler probes each with a single insonation frequencies of 2 MHz, 4 MHz or 8 MHz are characterized and compared for usefulness in this scenario. During in vitro experiments using an artificial blood circulatory with blood mimicking fluid bubbles with defined volumes were injected and recorded as gaseous embolic events. The in vitro results of measured embolus-blood-ratio values (EBR) in respect to the air bubbles volumes and its echogenicity showed a good correlation with the simulation model of spherical cross section scattering of such air bubbles. It is shown that the probe design still needs some improvements using a 4 MHz insonation frequency to get a useable detection sensitivity in such scenario within vena cava superior. The results suggest that it is possible to estimate the air bubble volume corresponding to the EBR using such a catheter probe., In diesem Beitrag wird ein Konzept zur Erkennung von venösen Luftembolien in der oberen Hohlvene vorgestellt, bei dem ein zentraler Venenkatheter mit integriertem Doppler-Ultraschallwandler an der Spitze genutzt wird. Mehrere Doppler-Sonden mit jeweils einer einzelnen Beschallungsfrequenz von 2 MHz, 4 MHz oder 8 MHz werden charakterisiert und auf ihre Nützlichkeit in diesem Szenario verglichen. Bei in vitro Experimenten mit einem künstlichen Blutkreislauf mit Blutsimulatinsflüssigkeit wurden Blasen mit definierten Volumina injiziert und aufgezeichnet. Die in vitro Ergebnisse der gemessenen Embolus-Blood-Ratio-Werte (EBR) in Bezug auf die Luftblasenvolumina und ihre Echogenität zeigten eine gute Korrelation mit dem Simulationsmodell der Streuung solcher Luftblasen im Kugelquerschnitt. Es zeigt sich, dass das Design der Sonde bei Verwendung einer 4 MHz-Insonationsfrequenz noch einiger Verbesserungen bedarf, um eine brauchbare Detektionsempfindlichkeit in einem solchen Szenario innerhalb der Vena cava superior zu erhalten. Die Ergebnisse legen nahe, dass es möglich ist, die Luftblasenvolumina abzuschätzen, die der EBR mit einer solchen Kathetersonde entsprechen.

Background: The autosomal dominant inherited trait of malignant hyperthermia (MH) may result in a fatal metabolic crisis triggered by volatile anaesthetics and/or succinylcholine. Immediate diagnosis and goal-directed therapy reduce the mortality of an acute MH event to less than 5%. In order to reach this goal, national and international recommendations, standard operating procedures (SOPs) and guidelines were published. Aim: In a German national survey among anaesthesiologists, the current study investigated the awareness level of SOPs and guidelines for preparedness and treatment of an acute MH-crisis. Material and Methods: An online questionnaire including questions about demography and personal experiences with MH was posted to all members of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI). Other questions were concerned with the existence of SOPs and guidelines for preparedness and treatment of an acute MH crisis in hospital or outpatient settings, as well as the individual rating of German and European guidelines. The questionnaire was active from the 2nd of September until the 30th of September 2015. Results: 1,673 members of the DGAI participated in the study. 94.5% of the participants stated that they used volatile anaesthetics and/or succinylcholine. 34.0% had witnessed one or more clinical MH episodes, and 44.9% had experienced at least one or more cases in which MH had been suspected. As regards the use of volatile anaesthetics 84.6% of the heads of anaesthesiological departments and 77.1% of self-employed anaesthesiologists working in in private practices stated that they hold available SOPs/guidelines on MH. 66.7% of the participants believed that the DGAI guidelines are adequate, whereas 22.0% preferred the guidelines released by the EMHG. However, 14.3% were not aware of DGAI or EMHG guidelines. Discussion: National and international anaesthesiological societies recommend that SOPs/guidelines for the prevention, recogniti

It is 30 yr since the British Journal of Anaesthesia published the first consensus protocol for the laboratory diagnosis of malignant hyperthermia susceptibility from the European Malignant Hyperthermia Group. This has subsequently been used in more than 10 000 individuals worldwide to inform use of anaesthetic drugs in these patients with increased risk of developing malignant hyperthermia during general anaesthesia, representing an early and successful example of stratified medicine. In 2001, our group also published a guideline for the use of DNA-based screening of malignant hyperthermia susceptibility. We now present an updated and complete guideline for the diagnostic pathway for patients potentially at increased risk of developing malignant hyperthermia. We introduce the new guideline with a narrative commentary that describes its development, the changes to previously published protocols and guidelines, and new sections, including recommendations for patient referral criteria and clinical interpretation of laboratory findings

It is 30 yr since the British Journal of Anaesthesia published the first consensus protocol for the laboratory diagnosis of malignant hyperthermia susceptibility from the European Malignant Hyperthermia Group. This has subsequently been used in more than 10 000 individuals worldwide to inform use of anaesthetic drugs in these patients with increased risk of developing malignant hyperthermia during general anaesthesia, representing an early and successful example of stratified medicine. In 2001, our group also published a guideline for the use of DNA-based screening of malignant hyperthermia susceptibility. We now present an updated and complete guideline for the diagnostic pathway for patients potentially at increased risk of developing malignant hyperthermia. We introduce the new guideline with a narrative commentary that describes its development, the changes to previously published protocols and guidelines, and new sections, including recommendations for patient referral criteria and clinical interpretation of laboratory findings