Active injection guide

Abstract

An active injection guide concurrently monitors surface contact and an instantaneous contact force along an injection axis of an injector in order to ensure that the injector is properly positioned on a patient before an injection can be initiated.

What is claimed is: 
     
         1 . An active injection guide comprising:
 an injector having an injection axis;   a contact surface configured to be placed on a target surface for an injection from the injector;   a contact sensor coupled to the contact surface, the contact sensor configured to detect an orientation of the injection axis to the target surface;   a load sensor coupled to the contact surface and configured to measure a force against the target surface along the injection axis; and   a controller configured to prevent activation of the injector until the orientation and the force are within predetermined ranges suitable for injection.   
     
     
         2 . The active injection guide of  claim 1  further comprising a feedback device configured to provide user feedback when the orientation and the force are within predetermined ranges suitable for injection. 
     
     
         3 . The active injection guide of  claim 2  wherein the feedback device includes at least one of a visual device, an audio device, and a haptic device. 
     
     
         4 . The active injection guide of  claim 1  wherein the contact sensor includes two spatially separated contact points, the two spatially separated contact points and the load sensor being arranged in a triangular pattern on the contact surface. 
     
     
         5 . The active injection guide of  claim 1  further comprising a controller configured to automatically initiate an injection when the orientation and the force are within predetermined ranges suitable for injection. 
     
     
         6 . The active injection guide of  claim 1  further comprising a controller configured to terminate the injection after the injection is initiated if the orientation or the force falls outside a corresponding predetermined range during the injection. 
     
     
         7 . The active injection guide of  claim 1  wherein the injector is a needle-free injector. 
     
     
         8 . The active injection guide of  claim 1  wherein the injector is an auto-injector. 
     
     
         9 . The active injection guide of  claim 1  further comprising a processor configured to calculate the orientation and the force based on signals from the contact sensor and the load sensor. 
     
     
         10 . The active injection guide of  claim 1  wherein the contact surface includes an injection protrusion extending past a plane of the contact surface toward the target surface along the injection axis when placed for use on the target surface, and wherein the load sensor is coupled to the injection protrusion and configured to detect an instantaneous contact force between the injection protrusion and the target surface. 
     
     
         11 . The active injection guide of  claim 10  wherein the injection protrusion causes a predefined deformation of the target surface relative to the contact surface when the contact sensor detects a contact between the contact surface and the target surface and the load sensor measures a target force in a predefined range of forces along the injection axis. 
     
     
         12 . The active injection guide of  claim 1  wherein the contact sensor is spatially separated from the load sensor. 
     
     
         13 . The active injection guide of  claim 1  wherein the contact sensor comprises an electrical impedance measuring sensor including a plurality of spatially separated electrically conductive contact points. 
     
     
         14 . The active injection guide of  claim 1  wherein the contact sensor comprises one or more mechanical switches. 
     
     
         15 . The active injection guide of  claim 1  wherein the contact sensor comprises one or more capacitive sensors. 
     
     
         16 . The active injection guide of  claim 1  wherein the load sensor comprises a strain gauge.