Table 1.
Subject characteristics and baseline physiological measurements.
Fig 1.
Schematic diagram of the model of peripheral vasoconstriction response to heat-induced pain.
Functional relationships between changes in temperature (ΔTemp), blood pressure (ΔMAP) and respiration (ΔVT) as inputs and changes in finger blood volume (ΔFBV) as the output. εFBV denotes extraneous fluctuations on FBV that are not captured by the model.
Table 2.
List of abbreviations.
Fig 2.
Representative data recorded during a test procedure in (a) a non-SCD subject and (b) a SCD subject. The top row shows changes in temperature (ΔTemp, °C). 0°C indicates no heat was delivered. Row 2 shows changes in beat-averaged blood pressure (MAP, mmHg). Row 3 shows changes in tidal volume (ΔVT, L). The bottom row shows corresponding changes in finger blood volume (ΔFBV, %).
Fig 3.
FBV response partitioned into contributions from each model component.
Predicted ΔFBV by each model component (thick lines) plotted on top of the measured ΔFBV (thin lines) during a test procedure in (a) a non-SCD subject and (b) a SCD subject, showing the relative contribution from each component on the total ΔFBV. The bottom row shows the sum of the predicted ΔFBV by all model components (thick line).
Fig 4.
Standardized FBV responses to a pain pulse and derived biophysical marker BMn.
(a) hTHM, standardized FBV responses to a pain pulse (mean ± SEM) in SCD (N = 22, thick line) and non-SCD (N = 23, thin line); (b) biophysical marker BMn capturing the initial neurogenic vasoconstriction caused by the direct effect of pain. Error bars show mean ± SEM. SCD had slightly stronger vasoconstriction than non-SCD (not statistically significant).
Fig 5.
Standardized FBV responses to a blood pressure pulse and derived biophysical marker BMv.
(a) hBPC, standardized FBV responses to a blood pressure increase (mean ± SEM) of SCD (N = 22, thick line) and non-SCD (N = 23, thin line); (b) biophysical marker BMv reflecting vasoconstriction as a result of blood pressure increase. Error bars show mean ± SEM. SCD had significantly stronger vasoconstriction than non-SCD after adjusting for age and sex (p = 0.0409).
Fig 6.
FBV responses of the interaction between pain and blood pressure and derived biophysical marker BMn-v.
(a) FBVBPCTHM, responses of the interaction between the simulated Temp and MAP pulses (mean ± SEM) in SCD (N = 22, thick line) and non-SCD (N = 23, thin line); (b) biophysical marker BMn-v reflecting total change in FBV as a result of the interaction between the two inputs. Error bars show mean ± SEM. SCD vasoconstricted while non-SCD vasodilated (p = 0.0167).