Table 2.

Physiological responses to HTS—all events, impaired and intact cerebrovascular reactivity

	Pre-HTS infusion	Post-HTS infusion	Mann-Whitney U (p value)
	Median (interquartile range)
All HTS administration events
ICP time above 22 mmHg (min)	16.33 (4.25 to 20.17)	4.67 (0.75 to 8.67)	0.0011*
ICP mean for 20 min window (mmHg)	23.23 (20.56 to 25.83)	18.52 (16.46 to 21.44)	< 0.0001*
CPP time below 60 mmHg (min)	0 (0 to 9.5)	0 (0 to 8.17)	0.91
CPP mean for 20 min window (mmHg)	67.65 (57.06 to 73.72)	72.95 (66.17 to 81.95)	0.02
AMP time above 2 mmHg (min)	20 (10.67 to 20)	12.92 (6.08 to 20)	0.22
AMP mean for 20 min window (mmHg)	2.84 (2.27 to 4.35)	2.27 (1.81 to 3.69)	0.09
PRx impaired (i.e., > + 0.30) prior to HTS
PRx time above + 0.30 (min)	20 (19 to 20)	17 (13.5 to 18)	< 0.0001*
PRx mean for 20 min window (a.u.)	0.83 (0.73 to 0.92)	0.53 (0.39 to 0.63)	< 0.0001*
RAP mean for 20 min window (a.u.)	0.73 (0.65 to 0.93)	0.84 (0.62 to 0.89)	0.72
PRx intact (i.e., < 0) prior to HTS
PRx time above + 0.30 (min)	0.5 (0.0 to 3.0)	3.5 (2.0 to 6.0)	0.01*
PRx mean for 20 min window (a.u.)	− 0.08 (− 0.21 to − 0.04)	− 0.04 (− 0.13 to 0.12)	0.19
RAP mean for 20 min window (a.u.)	0.83 (0.72 to 0.93)	0.88 (0.83 to 0.96)	0.22

For ICP, CPP, and AMP, the time is above their respective threshold and the mean value for the two 20-min windows with a 10-min delay. The time above/below threshold/mean value of PRx and the mean value RAP over the 20-min windows with a 10-min delay for PRx above + 0.3, and with a PRx below 0.0, before HTS infusion; median (interquartile range). A Mann-Whitney U test has been performed between each time segment

AMP, amplitude pulse of ICP; CPP, cerebral perfusion pressure; HTS, hypertonic saline; ICP, intracranial pressure; MAP, mean arterial pressure; min, minutes; mmHg, millimeters of mercury; PRx, pressure reactivity index (correlation between ICP and MAP); RAP, compensatory reserve index (correlation between AMP and CPP)

*p values are those reaching statistical significance (i.e., p < 0.05)