Well if u mean for how long ought the patient stay in bed without disturbance following receiving his thrombolysis then it is 24 hours.

Yet if the question how effective will be rtpa to make the patient active again then it all depends on the following:

First the degree of deficit and his NIHSS.

Second whether he had a previous stroke and if yes then his mRS.

Third onset to door and door to needle ( time is brain ).

Forth comprehensive physiotherapy (neuroplasticity).

Thank you @ Tamer- i wanted to know - the first part you answered.

why is that if half life of tpa is not that long ?

Well @ Sharma I suppose it is not related to half life of tpa which is as you mentioned not that long rather than following the NINDS part 1 study which waited for 24 hours then measuring NIHSS and comparing it to baseline NIHSS.

Another point is that all related monitoring guidelines are along first 24 hours either Bl/Pr, cardiac for AF and so on, and early mobilization may disturb these readings.

Also it is a matter of agreement between physicians in a study of fifty-four clinicians found that perceived risk of neurological decline, especially due to sICH; infection of unknown cause; severe chest infection; severe stroke (NIHSS >20); drowsiness and confusion were factors that significantly influenced the decision to mobilize early.

Article Bed Rest or Mobilization after rt-PA? A Case-Crossover Study...