British journal of anaesthesia
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In the last decade, stents suitable for the management of tracheobronchial stenoses and obstruction have evolved from bulky prostheses requiring tracheal resection to small devices that are self-expanding and can be inserted using fibreoptic techniques. The experience base for this review is more than 100 patients between 1989 and 2001 who have been anaesthetized for stent insertion. Early cases required rigid bronchoscopy for the routine of insertion. ⋯ But the original one, based on the requirement for use of a rigid bronchoscope, is best for dealing with complications and extracting problem stents. The most frequent complication of the processes of stent insertion has been respiratory failure because of carbon dioxide retention, consequent on obstruction with secretions in the area of the carina. The nature of central airway problems suggests that anaesthesia induction, management and teaching should not be founded on the conventional model-base of upper airway obstruction.
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Cerebral perfusion pressure (CPP) is commonly calculated from the difference between arterial blood pressure (AP) and intracranial pressure (ICP). ICP can be considered the effective downstream pressure of the cerebral circulation. Consequently, cerebral circulatory arrest would occur when AP equals ICP. Estimation of AP for zero-flow pressure (ZFP) may thus allow estimation of ICP. We estimated ZFP from cerebral pressure-flow velocity relationships so that ICP could be measured by transcranial Doppler sonography. ⋯ Extrapolation of cerebral ZFP from instantaneous AP-V(MCA) relationships enables detection of severely elevated ICP and may be a useful and less invasive method for CPP monitoring than other methods.