No abstract

Despite maintaining arterial pressure with phenylephrine, cerebral desaturation occurred with upright positioning. Cerebral oxygen saturation can provide a valuable endpoint when evaluating the effect of vasopressor therapy on cerebral perfusion.

Sympathomimetic-based vasopressor agents constrict both human radial and pulmonary arteries with similar potency in each. In contrast, vasopressin, although a potent vasoconstrictor of radial vessels, had no effect on pulmonary vascular tone. These findings provide some support for the use of vasopressin in patients with pulmonary hypertension.

Ultrasound guidance allows real-time identification of relevant anatomy and needle position when performing brachial plexus regional anaesthesia. The aim of this investigation was to determine whether the use of surface ultrasound could improve the quality of brachial plexus anaesthesia for upper limb surgery. Forty patients were randomized to either conventional "landmark-based" plexus anaesthesia, or to an ultrasound-guided approach using a 13 mHz linear array transducer. Both interscalene and axillary techniques were used. The use of ultrasound significantly improved the onset and completeness of sensory (P=0.011) and motor (P=0.002) block. Ultrasound guidance also significantly reduced (P=0.012) the incidence of paraesthesia during the performance of the blocks. Ultrasound guidance increases the quality of sensory and motor blockade in brachial plexus regional anaesthesia, and by reducing the incidence of paraesthesia during performance of the blocks, may confer greater safety.

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The aim of this study was to investigate if endurance training during juvenile life 'reprogrammes' the heart and leads to sustained improvements in the structure, function, and morphology of the adult heart. Male Wistar Kyoto rats were exercise trained 5 days week for 4 weeks in either juvenile (5-9 weeks of age), adolescent (11-15 weeks of age) or adult life (20-24 weeks of age). Juvenile exercise training, when compared to 24-week-old sedentary rats, led to sustained increases in left ventricle (LV) mass (+18%; P < 0.05), wall thickness (+11%; P < 0.05), the longitudinal area of binucleated cardiomyocytes (P < 0.05), cardiomyocyte number (+36%; P < 0.05), and doubled the proportion of mononucleated cardiomyocytes (P < 0.05), with a less pronounced effect of exercise during adolescent life. Adult exercise training also increased LV mass (+11%; P < 0.05), wall thickness (+6%; P < 0.05) and the longitudinal area of binucleated cardiomyocytes (P < 0.05), despite no change in cardiomyocyte number or the proportion of mono- and binucleated cardiomyocytes. Resting cardiac function, LV chamber dimensions and fibrosis levels were not altered by juvenile or adult exercise training. At 9 weeks of age, juvenile exercise significantly reduced the expression of microRNA-208b, which is a known regulator of cardiac growth, but this was not sustained to 24 weeks of age. In conclusion, juvenile exercise leads to physiological cardiac hypertrophy that is sustained into adulthood long after exercise training has ceased. Furthermore, this cardiac reprogramming is largely due to a 36% increase in cardiomyocyte number, which results in an additional 20 million cardiomyocytes in adulthood.

The aim of this study was to define the anatomy relevant to brachial plexus regional anaesthesia and to identify the extent of variation between individuals. Surface ultrasound examination of the brachial plexus was performed on twenty volunteers. In the axilla there was considerable individual variation in the location of the median, radial and ulnar nerves in relation to the axillary artery. There was often more than one venous structure in this region, which was easily compressed by surface palpation. In the supraclavicular region, neural elements were located inferiorly to the subclavian artery in two volunteers. In one volunteer, a vein was identified between nerve trunks in the interscalene region. These findings indicate that the anatomical variation is considerable, even within the relatively small sample studied. For this reason, use of surface ultrasound may lead to increased success of brachial plexus regional anaesthesia and a decreased risk of intravascular injection.

Purpose The purpose of this narrative review is to describe an anatomical approach for residents-in-training and anesthesiologists who are learning techniques of ultrasound-guided regional anesthesia of the neck and upper limb Sources Relevant articles relating anatomy and anatomical variation to the emerging practice of ultrasoundguided regional anesthesia for the neck and upper limb were sourced via both Medline and PubMed databases. Also, our approach to teaching ultrasound technique has developed from using anatomical resources and cadaveric workshops. This approach emphasizes precise image acquisition, a detailed knowledge of anatomy and anatomical variations, and, importantly, visual interpretation of sonographic landmarks based on pattern recognition when interpreting sonograms. Principal findings Typical sonographic patterns orient the examiner to nerve position, which is necessary for executing successful regional anesthesia of the neck and upper limb. Only by understanding the typical anatomical arrangement can the examiner then visually interpret any individual anatomical variation that may occur. Conclusion Simple sonographic anatomical patterns can provide a strategy to correctly locate nerves when performing ultrasound-guided cervical and brachial plexus anesthesia. RésuméObjectif L'objectif de ce compte-rendu narratif est de de´crire une approche anatomique destine´e aux re´sidents en formation et aux anesthe´siologistes qui apprennent les techniques d'anesthe´sie re´gionale du cou et des membres supe´rieurs par e´choguidage. Sources Les articles pertinents traitant de l'anatomie et des variations anatomiques dans la pratique e´mergente de l'anesthe´sie re´gionale du cou et des membres supe´rieurs par e´choguidage ont e´te´tire´s des bases de donne´es Medline et PubMed. De plus, notre approche de l'enseignement des techniques e´choguide´es a e´volue´graˆce au recours ad es ressources anatomiques et des ateliers sur des cadavres. Cette approche met l'accent sur l'obtention d'images pre´cises, une connaissance de´taille´e de l'anatomie et des variations anatomiques et, composante importante, l'interpre´tation visuelle de points de repe`res e´chographiques selon une reconnaissance des configurations lors de l'interpre´tation des e´chogrammes. Constatations principales Les configurations e´chog-raphiques typiques fournissent des informations al 'examinateur quant a`la position des nerfs, ce qui est ne´cessaire a`la re´alisation d'une anesthe´sie re´gionale du cou et des membres supe´rieurs re´ussie. Il faut que l'examinateur comprenne la disposition anatomique typique pour ensuite pouvoir interpre´ter de façon visuelle les variations anatomiques individuelles potentielles.