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Response to the Valsalva manoeuvre after spinal anaesthesia
Author(s) -
MACFIE A. G.,
BRIMACOMBE J.
Publication year - 1992
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.1992.tb01944.x
Subject(s) - medicine , spinal anesthesia , anesthesia , valsalva maneuver , regional anaesthesia , blood pressure
Summary The waveform from a Criticare 504 pulse oximeter was recorded during the performance of a standard Valsalva manoeuvre in 20 patients before and after spinal anaesthesia. The pulse oximeter waveform showed changes typical of the expected heart rate and pulse volume changes seen in each phase of the Valsalva manoeuvre. There were no significant changes in the typical pulse volume changes of the Valsalva manoeuvre after spinal anaesthesia, which achieved a sensory block ranging in upper extent from T 3 ‐T 12 . There was, however, a significant delay in recovery of the pulse volume in phase 4 of the Valsalva manoeuvre after spinal anaesthesia from a mean (SD) of 3.1 (0.9) s to 6.2 (3.1) s (p < 0.05). There was also a significant reduction in reflex bradycardia seen in phase 4. However, this was found only at 5, 10 and 15 min after spinal anaesthesia and was not associated with a significant change in Valsalva ratio or maximum‐to‐minimum rate ratio. The study confirms that the normal response to a standard Valsalva manoeuvre is suppressed only mildly during spinal anaesthesia in normovolaemic fit patients.