[Hemodynamic monitoring - imaging procedures / cardiac ultrasound]. / Hämodynamisches Monitoring - Bildgebende bzw. Ultraschallverfahren.

Echocardiography as an imaging method in anaesthesia and intensive care medicine has enabled a new dimension of hemodynamic monitoring: the direct visualization of the cardiac function and its disruptions. Preconditions for a broad application in this area was the development of mobile, high-definition ultrasonic devices and the origination of focused examination techniques. A successful application of this method requires the respective know-how of the examiner, in order to take relevant decisions and avoid misdiagnoses. The following article shows the advantages and limitations of echocardiography in the diagnosis of hemodynamic instability. For TTE and TEE focused examination techniques are illustrated and evaluated with regards to their applicability to hemodynamic monitoring. Furthermore, the requirements on devices and education of the examiner are discussed.

[Does anesthesia harm children's brain?]. / Kinderanästhesie--Macht Narkose dumm?

Animal data, that could show a correlation between anesthetic exposure and longterm damage to the developing brain, have raised concern within the international anesthesiology community, but also in patients, parents and media. The evaluation of the available literature does not provide evidence for changes in routine anesthetic practice associated with the order, to establish evidence through increased basic and clinical research about the mechanisms and possible effects in humans.

Does anatomical completeness of the circle of Willis correlate with sufficient cross-perfusion during unilateral cerebral perfusion?

OBJECTIVES: The aim of the study was to evaluate the role of anatomical completeness of the circle of Willis for sufficient brain perfusion during unilateral cerebral perfusion and the methodology of the preoperative and intraoperative functional assessments of adequate cross-perfusion. METHODS: This prospective observational study included all elective patients (99) who underwent elective open arch surgery (hemiarch in 74 and arch replacement in 25 patients, respectively) at our institution between September 2004 and September 2006. Preoperative neuro-vascular evaluation included color-coded duplexsonography of the extracranial arteries, cranial CT angiography, and transcranial sonography. A functional test of cerebral cross-perfusion was performed during cross-clamping of the common carotid artery during cannulation by transcranial Doppler, electroencephalography and measurement of somatosensory evoked potentials. These examinations, which were completed through measurement of arterial pressure in both radial arteries, also served as an intraoperative assessment of cerebral perfusion during surgery. During mild hypothermic (30 degrees C) circulatory arrest with a mean duration of 18 min (range, 7-70) brain protection using unilateral cerebral perfusion was performed in all patients. RESULTS: As assessed in preoperative CT angiography, the circle of Willis was complete in only 59 patients. Eighteen patients showed a singular abnormal location within the circle of Willis, 13 patients presented with abnormalities within the posterior communicating arteries on both sides, and 9 patients within the anterior and posterior communicating arteries. Nevertheless, functional tests during carotid artery cross-clamping as well as intraoperative cerebral monitoring including transcranial Doppler showed no pathology in any patient, and only one patient with severe aortic valve calcification suffered from embolic minor stroke after surgery. CONCLUSIONS: The anatomical status of the circle of Willis assessed with cranial CT angiography does not correlate with functional and intraoperative tests examining the cerebral cross-perfusion. The authors do not recommend cranial CT angiography as a preoperative standard examination before open arch surgery in which unilateral cerebral perfusion is scheduled.