An apparatus includes a catheter, an introducer having a first member and a second member, a locking mechanism coupled to a distal end of the first member and configured to couple the introducer to a peripheral intravenous line, and an actuator coupled to the catheter. The actuator is configured to move from a first configuration, in which the catheter is disposed within the introducer, toward a second configuration to move the second member to a distal position relative to the first member. A portion of a guide of the second member being distal to the first member when the second member is in the distal position. The actuator is configured to move relative to the second member to be placed in the second configuration when the second member is in its distal position such that the catheter is disposed within and extending past an end of the peripheral intravenous line.