Table 2. Experimental protocol.

phase	process (patient in supine position)	duration (min)
1.	instrumentation, calibration, test measurement	20
2.	recovery	5
3.	steady state	2
4.	bolus administration of phenylephrine and nitroprusside	2
4.	recovery	5
5.	bolus administration of phenylephrine and nitroprusside	2
6.	recovery	5
7a.	steady state	6
7b.	HUT	5
7c.	steady state	2
7d.	administration of phenylephrine and nitroprusside	2
7e.	recovery after backward tilt	8
8.	repetition of 7.	23