An infusion pump for metering fluid flow through an delivery tube of an infusion tubing set has an internal occlusion clamp which clamps the delivery tube to prevent the free flow of fluid through the tube when access to the delivery tube in the infusion pump is possible. To release the delivery tube from the infusion pump, a slide clamp is manually used to release the occlusion clamp to an open, non-occluding position while simultaneously occluding the delivery tube to prevent the free flow of fluid.