the present invention provides apparatuses and methods to safely and economically deliver infusion fluid to a patient during a medical procedure . the infusion fluid may be a sedative , analgesic , amnestic or other pharmaceutical agent for alleviating a patient &# 39 ; s pain and anxiety before , during and / or after a medical or surgical procedure . in general the apparatus comprises a microprocessor - based controller that receives inputs from a plurality of physiological monitors attached to a patient . the system controller processes the data from the physiological monitors and based upon a fluid infusion algorithm delivers infusion fluid to a patient . the physiological monitors monitor the patient throughout the course of the procedure and depending upon the health of the patient , drug delivery may be adjusted to optimize the procedure while ensuring the patient &# 39 ; s health is maintained . functionality detectors such as an occlusion sensor , air - in - line sensor and a fluid detection sensor alert a clinician to such hazards as a pressure build up in the infusion line , air - bubbles in the infusion line , and the absence of fluid in the infusion line .