Eleven studies were included in the review (n=285). Sample sizes ranged from four to 98. One study was a randomised controlled trial (RCT) (n=82) and one was a controlled nonrandomised study (n=98); other trials were uncontrolled. Eight studies were prospective designs and two of these reported using consecutive enrolment of patients.
Short-term effects of prophylactic use: Hypervolaemia showed contradictory nonsignificant changes from baseline in three studies. There was no statistically significant difference between hypervolaemia and the comparison group in the single controlled study. Hypertension was associated with increased cerebral blood flow over baseline in two studies; this was statistically significant in one study. Triple-H therapy was associated with increased cerebral blood flow over baseline in two studies; this was statistically significant in one study.
Short-term effects of therapeutic use: Hypertension was associated with increased cerebral blood flow from baseline in all three studies; this was statistically significant in one study. Hypervolaemia had no statistically significant effect in any of three studies and the directions of the effects were inconsistent. Haemodilution was associated with a nonsignificant increase in cerebral blood flow in one study.
Long-term effects: Two controlled studies reported on long-term effects of hypervolemia; one was prophylactic and one was therapeutic. In the prophylactic study, hypervolaemia was reported to be associated with a nonsignificant decrease in cerebral blood flow compared to a nonsignificant increase in the control group; in the therapeutic study hypervolaemia was associated with a significant increase in cerebral blood flow over baseline and the control group showed no significant change.