Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Transcranial Doppler sonography (TCD) constitutes an advance in noninvasive monitoring of the cerebral circulation. However, as long as the diameter and cross-sectional area of the insonated middle cerebral artery (MCA) remain unknown, the derived flow velocities (v) are not informative. It is not known how the human MCA is influenced by anaesthetic agents. ⋯ The MAP, FECO2, and v showed only minor alterations; HR increased after 6, 10 and 20 min. Transcranial "vessel area" and "volume flow" showed increases after isoflurane inhalation. The increase of "vessel area" supports the assumption that isoflurane greater than 1 MAC dilates large human cerebral arteries, so that if flow velocities are considered alone, alterations of cerebral blood flow may easily be underestimated.
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The combined spinal-epidural technique is a modification of epidural analgesia which combines the rapid onset of spinal analgesia with the flexibility of an epidural catheter. We sought to evaluate the effectiveness of an intrathecal opioid--low-dose local anaesthetic combination for parturients in advanced labour, a setting where satisfactory epidural analgesia is often difficult to achieve. The technique was evaluated in an open-label, non-randomized trial using parturients in advanced, active labour for the provision of pain relief during the late first stage and second stage of labour. ⋯ Onset of analgesia was rapid (< five minutes) in all cases. Twenty-three patients (60%) delivered vaginally with no additional anaesthetic. The remaining 15 had supplemental local anaesthetic given via the epidural catheter, a mean of 123 +/- 33 min after the original spinal dose.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comment Letter
The oesophageal tracheal combitube for difficult intubation.