Figure 4. Representative recordings of aggregation and intracellular free Calcium2+ concentration of human platelets during exposure to thrombin (closed triangle) and (A) halothane or (B) isoflurane in the absence of external Calcium2+ (with 50 micro Meter EGTA). Samples of washed platelet suspension were pretreated with halothane or isoflurane 2 min before exposure to 0.02 units/ml thrombin.