Table 1.
Characteristics of the study participants.
Data are presented as mean values and standard deviations (SD).
Fig 1.
Schematic representation of the study design.
Table 2.
Effects of 60 s Mueller manoeuvres series on SAS, SBP, DBP, HR, CBFV, PI, RI and SaO2.
Data are presented as mean values and standard deviations (SD). All % changes are calculated with reference to baseline values.
Table 3.
Multivariate regression analysis.
Model explaining changes in cardiac SAS component with relation to cerebral blood flow velocity, heart rate, oxyhaemoglobin saturation and blood pressure fluctuations in response to the beginning and terminal part of the Mueller manoeuvres.
Fig 2.
Representative tracings from 10 s BP and SAS signals with corresponding wavelet transforms; baseline (panel A), WCO minimum (panel B) and WCO maximum (panel C) from one of participants. The SAS signal (in blue) is less regular than the BP signal (in red). Wavelet transform analysis reveals BP and SAS peaks at cardiac frequency marked with vertical magenta dotted lines (SAS analysis in blue, BP in red). Alterations in cardiac frequency are apparent throughout the Mueller manoeuvres.
Fig 3.
Representative tracings of 10 s signals of baseline (in green), 10 s of minimum WCO (in blue) and 10 s of maximum WCO (in red).
BP oscillations (panel A), SAS oscillations (panel B) and WCO (panels C, D and E). Cardiac frequency is indicated by vertical, magenta, dotted lines. Black solid lines (panels from C to E) illustrate results obtained for IAAFT surrogates.
Fig 4.
Representative WCO (panel B) and WPCO (panel C) tracings. BP (red) and SAS (blue) signals are provided in the panel A. WCO reaches its minimum between 8 and 18 s of the Mueller manoeuvres, and later upon recovery, reaches its maximum between 35 and 45 s for cardiac frequency. WPCO remains stable. Cardiac frequency is indicated by horizontal dotted lines.
Table 4.
Effects of a 60 s Mueller manoeuvres series on WCO and WPCO between BP and SAS oscillations at cardiac frequency.
Data are presented as mean values and standard deviations (SD). The minimum and maximum correspond to WCO minimum and maximum values during the Mueller manoeuvres series.