A fluid delivery device to treat a host, comprising: a housing containing a fluid reservoir , a first sensor configured to measure a physiological parameter of the host, a transcutaneous access tool , and a transcutaneous access tool insertion mechanism ; the fluid reservoir to contain a therapeutic fluid; the transcutaneous access tool fluidly coupled to the fluid reservoir , the transcutaneous access tool configured to deliver the therapeutic fluid and the first sensor subcutaneously into tissue of the host; the transcutaneous access tool including a cannula having a first lumen fluidly coupled with the fluid reservoir , and a deployable and retractable needle/trocar located within the first lumen ; the transcutaneous access tool insertion mechanism configured to extend and insert the cannula and first sensor together with the needle/trocar subcutaneously into the tissue of the host upon deployment of the needle/trocar , and thereafter retract the needle/trocar within the first lumen of the cannula while the cannula and first sensor remain inserted subcutaneously in the tissue of the host; and the fluid delivery device configured to measure a value of the physiological parameter using the first sensor after delivery of the therapeutic fluid to the host within a predetermined time period after delivery of the therapeutic fluid, wherein the predetermined time period is in a range of 0.1 second to 300 seconds, and compare the after measured value to a predetermined representative value for the physiological parameter to confirm delivery of the therapeutic fluid to the host, or a before measured value of the physiological parameter measured using the first sensor before delivery of the therapeutic fluid to the host to confirm delivery of the therapeutic fluid to the host. a housing containing a fluid reservoir , a first sensor configured to measure a physiological parameter of the host, a transcutaneous access tool , and a transcutaneous access tool insertion mechanism ; the fluid reservoir to contain a therapeutic fluid; the transcutaneous access tool fluidly coupled to the fluid reservoir , the transcutaneous access tool configured to deliver the therapeutic fluid and the first sensor subcutaneously into tissue of the host; the transcutaneous access tool including a cannula having a first lumen fluidly coupled with the fluid reservoir , and a deployable and retractable needle/trocar located within the first lumen ; the transcutaneous access tool insertion mechanism configured to extend and insert the cannula and first sensor together with the needle/trocar subcutaneously into the tissue of the host upon deployment of the needle/trocar , and thereafter retract the needle/trocar within the first lumen of the cannula while the cannula and first sensor remain inserted subcutaneously in the tissue of the host; and the fluid delivery device configured to measure a value of the physiological parameter using the first sensor after delivery of the therapeutic fluid to the host within a predetermined time period after delivery of the therapeutic fluid, wherein the predetermined time period is in a range of 0.1 second to 300 seconds, and compare the after measured value to a predetermined representative value for the physiological parameter to confirm delivery of the therapeutic fluid to the host, or a before measured value of the physiological parameter measured using the first sensor before delivery of the therapeutic fluid to the host to confirm delivery of the therapeutic fluid to the host. a predetermined representative value for the physiological parameter to confirm delivery of the therapeutic fluid to the host, or a before measured value of the physiological parameter measured using the first sensor before delivery of the therapeutic fluid to the host to confirm delivery of the therapeutic fluid to the host. <EOS>