ABSTRACT
We present a case of awake tracheal intubation with flexible bronchoscopy which resulted in incorrect tracheal tube placement. The presence of a stenotic subglottic lesion with an appearance similar to the carina led to the tube being positioned with only the tip within the trachea whilst the cuff was located between the vocal cords. A capnography trace was identified before induction of anaesthesia; however, visual confirmation of the carina was undertaken in a rushed manner due to the patient becoming agitated. Once the incorrect tracheal tube placement was identified, the decision was made to wake the patient. Thereafter, a more experienced operator successfully performed awake tracheal intubation with flexible bronchoscopy using a smaller tracheal tube, which easily passed through the subglottic stenosis. This report emphasises the importance of performing the 'two-point check' every time awake tracheal intubation is undertaken: to confirm correct tube placement, both a capnography trace and view of the tracheal lumen including the carina and main bronchi is required. This must be properly performed before induction of anaesthesia; safety should not be compromised by a stressful environment or time pressure.
ABSTRACT
PURPOSE: To quantify the crowding effect with eccentric stimuli and to determine the relative contribution of neural interaction and attention to crowding in central and eccentric vision. METHODS: Monocular visual acuity was measured with computer-generated tumbling E and Landolt C targets presented centrally or at 2 degrees in the right visual field. Crowding distractors were designed to cause increasing contour interaction or increasing need for focused attention. A four-alternative forced-choice method of constant stimuli was used. In experiment 2 the distance between the target and the distractors was varied. RESULTS: Data are presented in terms of normalized visual acuity. Crowding in central vision was minimal, mainly caused by contour interaction, and did not occur with distractors more than four stroke widths distant. Crowding in eccentric vision was far greater in magnitude and extent (occurring for distractors as far as 16 stroke widths distant) and was caused by contour interaction and attentional factors. CONCLUSIONS: The results indicate that eccentric vision differs quantitatively and qualitatively from central vision. The extent of contour interaction effects are consistent with the proposed size of cortical processing zones. The results are discussed with reference to current theories of preattentive and attentive tasks and with reference to subjects with low vision due to central scotoma who use an eccentric retinal locus for fixation.
Subject(s)
Attention , Retina/physiology , Visual Acuity/physiology , Adult , Eye Movements/physiology , Female , Fixation, Ocular/physiology , Humans , Male , Vision TestsABSTRACT
The present study investigated whether there is a statistically significant correlation between platelet aggregation inhibition (TAI) and prolongation of subaqueous bleeding time (SBT) under therapy with 40 mg (n = 20) and 500 mg (n = 20) acetylsalicylic acid (ASA) daily and when parameters return to normal after discontinuation of long-term (4 weeks) and short-term (1 week) treatment. The results of this study may be helpful in clinical practice when deciding upon indications for certain operative or anaesthetic procedures. RESULTS. Under ASA treatment, neither TAI nor prolongation of SBT was dependent on dosage or time (Figs. 1-4). After discontinuation of ASA, platelet aggregation returned to normal 1-4 days later than SBT, depending on the dosage and duration of medication. SBT declined to its initial value on the 3rd day following discontinuation of ASA in both dosage groups (Figs. 2 and 4). Normalisation of platelet aggregation depended on dosage: in those groups with 40 mg ASA, thrombocyte aggregation had normalised on the 4th day irrespective of duration of medication; in groups with 500 mg aggregation capacity was completely restored on the 5th day after 1-week therapy and on the 7th day after 4-week therapy (Figs. 1 and 3). Considering these results, an important factor is the time of discontinuation of ASA intake. Prior to scheduled operative procedures or regional anaesthetics near the spinal cord, ASA should be discontinued, depending on the dosage, 2-3 days ahead. At this time SBT has reached the initial value, however, the aggregation capacity of thrombocytes is still reduced for a few days.(ABSTRACT TRUNCATED AT 250 WORDS)
