-
- C Werner, E Kochs, R Reimer, M Rau, and J Schulte am Esch.
- Abteilung für Anaesthesiologie, Universitäts-Krankenhaus Eppendorf, Hamburg.
- Anaesthesist. 1990 Sep 1;39(9):429-33.
AbstractAnesthesia may compromise the regulation of systemic and cerebral hemodynamics following changes in body position. Sudden decreases in cerebral perfusion pressure due to changes from a horizontal to a head-elevated position may cause decreases in cerebral blood flow (CBF), particularly in patients with preexisting cerebrovascular disease. Transcranial Doppler sonography (TCD) permits on-line measurement of blood flow velocity (BFV) in human basal cerebral arteries, and there is evidence that monitoring of BFV may indicate relative changes in CBF. The present study compares the effects of changes from a horizontal to a head-elevated position on blood flow velocity in the middle cerebral artery (MCA) in 30 patients (ASA I) with different levels of steady state anesthesia (group A: n = 20, isoflurane = 1.0 vol% end-tidal; group B: n = 10, isoflurane = 0.4 vol% end-tidal; O2/N2O; FiO2: 0.3; 6 1/min). The MCA was insonated by transtemporal approach using a 2 MHz Doppler ultrasound system (TC2-64 B, EME) with a range-gating mechanism, adjustable sample volume depth, and flow direction discrimination. Systolic (Vsyst, cm/s) and mean flow velocity (Vmean, cm/s), pulsatility index (PI), mean arterial blood pressure (MAP, mmHg), heart rate (HR, b/min) and end-tidal CO2 (pet-CO2, mmHg) were recorded with the subjects lying flat (baseline values) and for 5 min following adjustment to a 35-40 degrees head-elevated position. There was a significant reduction of 25% for Vsyst from 79 +/- 17 cm/s (baseline) to 59 +/- 13 cm/s and a 33% decrease for Vmean from 52 +/- 9 cm/s (baseline) to 35 +/- 9 cm/s in group A immediately after repositioning.(ABSTRACT TRUNCATED AT 250 WORDS)
Notes
Knowledge, pearl, summary or comment to share?You can also include formatting, links, images and footnotes in your notes
- Simple formatting can be added to notes, such as
*italics*
,_underline_
or**bold**
. - Superscript can be denoted by
<sup>text</sup>
and subscript<sub>text</sub>
. - Numbered or bulleted lists can be created using either numbered lines
1. 2. 3.
, hyphens-
or asterisks*
. - Links can be included with:
[my link to pubmed](http://pubmed.com)
- Images can be included with:
![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
- For footnotes use
[^1](This is a footnote.)
inline. - Or use an inline reference
[^1]
to refer to a longer footnote elseweher in the document[^1]: This is a long footnote.
.