Administration apparatus for medical use

Abstract

An expansion/compression mechanism of a piston rod assembly is composed of a bush shaft, a first cylindrical piston rod that is screwed with the bush shaft, a second cylindrical piston rod that is screwed with the first piston rod, and a piston rod holding member for housing the bush shaft and the piston rods. Therefore, the piston rods move linearly in multiple stages, whereby the size of the whole apparatus is reduced.

1 . An administration apparatus for medical use including: 
 a drug cartridge having an end closed with a plunger, and containing a drug inside;    a cartridge holder for holding the drug cartridge;    a needle holder which is provided at an end of the cartridge holder slidably in the axial direction of the cartridge holder, and is swingable with respect to the axial direction at its sliding end portion; and    a needle assembly for inserting a needle into a target region, and administrating the drug that is ejected from the other end of the drug cartridge by a movement of a piston rod that presses the plunger in the drug cartridge, said needle assembly being detachably provided onto the needle holder;    wherein the needle holder is slid in the axial direction of the cartridge holder as well as it is swung with respect to the axial direction at its sliding end portion, thereby exposing a front end portion of the drug cartridge at the front end of the cartridge holder to detach the drug cartridge from the cartridge holder.    
     
     
         2 . An administration apparatus for medical use as defined in  claim 1  wherein 
 detaching of the drug cartridge is possible in a state where the needle assembly is attached to the needle holder.    
     
     
         3 . An administration apparatus for medical use as defined in  claim 1  wherein 
 the needle holder is provided with a lever for moving the drug cartridge toward the piston rod with the operation of attaching the needle assembly to the needle holder.    
     
     
         4 . An administration apparatus for medical use as defined in  claim 1  wherein 
 the cartridge holder is provided with a force-applying member for pushing the drug cartridge toward the needle holder.    
     
     
         5 . An administration apparatus for medical use as defined in  claim 1  wherein 
 when replacing the drug cartridge, the piston rod is moved back to its initial position with the operation of moving the needle holder toward the position where the needle assembly is attached.    
     
     
         6 . An administration apparatus for medical use as defined in  claim 1  further including 
 a movable target-region contact cover that covers the peripheral side surface of the needle holder,    wherein, when performing injection, only a needle of the needle assembly is exposed from the target-region contact cover.    
     
     
         7 . An administration apparatus for medical use as defined in  claim 6  wherein 
 when replacing the drug cartridge, the target-region contact cover is moved to the position where the needle holder is exposed.    
     
     
         8 . An administration apparatus for medical use as defined in  claim 6  further including 
 a unit for detecting the position of the target-region contact cover.    
     
     
         9 . An administration apparatus for medical use including: 
 a drug cartridge having an end closed with a plunger, and containing a drug inside;    a cartridge holder for holding the drug cartridge; and    a piston rod assembly having plural stages of expansion/compression mechanisms, and pushing the plunger in the drug cartridge to move the plunger.    
     
     
         10 . An administration apparatus for medical use as defined in  claim 9 , wherein 
 the plural stages of expansion/compression mechanisms of the piston rod assembly having plural stages of piston rods which are linearly slidable in parallel to the axial direction of the cartridge holder, and the length of each piston rod is shorter than the whole length of the drug cartridge.    
     
     
         11 . An administration apparatus for medical use as defined in  claim 10  wherein 
 the plural piston rods are concentrically arranged, and the piston rods are successively slid from the piston rod that is positioned at the outermost concentric circle.    
     
     
         12 . An administration apparatus for medical use which performs administration of a drug using an electric driving source, said apparatus comprising: 
 a drug cartridge having an end closed with a plunger, and containing a drug inside;    a cartridge holder for holding the drug cartridge;    a piston rod for pressing the plunger held in the drug cartridge to move the plunger;    a needle assembly for inserting a needle into a target region, and administering the drug that is emitted from the other end of the drug cartridge with a movement of the piston; and    a control circuit for controlling an air releasing operation for the drug cartridge and/or the injection needle so that the air releasing operation is carried out at a speed lower than the speed of drug administration.    
     
     
         13 . An administration apparatus for medical use as defined in  claim 12  wherein 
 the air releasing operation is carried out with the movement of the piston rod.    
     
     
         14 . An administration apparatus for medical use as defined in  claim 13  wherein 
 during the air releasing operation, the piston rod is moved at a speed lower than the speed of the piston rod during drug administration.    
     
     
         15 . An administration apparatus for medical use as defined in  claim 14  wherein 
 the low-speed operation of the piston rod during the air releasing operation is performed by PWM (Pulse Width Modulation) control for controlling the piston rod with the ON-OFF ratio of the pulse width being varied.    
     
     
         16 . An administration apparatus for medical use as defined in  claim 14  wherein 
 the low-speed operation of the piston rod during the air releasing operation is performed by voltage control.    
     
     
         17 . An administration apparatus for medical use which performs administration of a drug using an electric driving source, said apparatus comprising: 
 a drug cartridge having an end closed with a plunger, and containing a drug inside;    a cartridge holder for holding the drug cartridge;    a piston rod for pressing the plunger in the drug cartridge to move the plunger;    a needle assembly for inserting a needle into a target region, and administering the drug that is emitted from the other end of the drug cartridge with a movement of the piston rod; and    a control circuit for performing control so that an air releasing operation for the drug cartridge and/or the injection needle is always carried out before performing the drug administration operation.    
     
     
         18 . An administration apparatus for medical use as defined in  claim 17  further including 
 an air releasing switch for performing the air releasing operation, and an administration switch for injecting the drug,    wherein the control circuit permits an operation by turn-on of the administration switch after the air releasing operation.    
     
     
         19 . An administration apparatus for medical use as defined in  claim 12  further including 
 a contact sensor for detecting whether a portion of the administration apparatus in the vicinity of the needle assembly contacts a target region or not,    wherein the air releasing operation is suppressed when the contact sensor contacts the target region.    
     
     
         20 . An administration apparatus for medical use which performs administration of a drug using an electric driving source, said apparatus comprising: 
 a drug cartridge having an end closed with a plunger, and containing a drug inside;    a cartridge holder for holding the drug cartridge;    a piston rod for pressing the plunger in the drug cartridge to move the plunger;    a needle assembly for inserting a needle into a target region, and administering the drug that is emitted from the other end of the drug cartridge with a movement of the piston rod;    a dose setting circuit for setting, by a user, a dose of drug to be administered;    a dose holding circuit for holding doses of drug which have been administered in the past;    a dose comparison circuit for comparing the dose that is set by the dose setting circuit with the doses that are held in the dose holding circuit; and    a control circuit for performing control so as to suppress the operation of the piston rod when the result of comparison by the dose comparison circuit is equal to or larger than a predetermined value.    
     
     
         21 . An administration apparatus for medical use as defined in  claim 20  wherein 
 the dose holding circuit holds the dose of drug that has been administered most recently, and    the dose comparison circuit compares the dose that is set by the user with a dose that has most recently been administered.    
     
     
         22 . An administration apparatus for medical use as defined in  claim 20  wherein 
 the dose holding circuit holds the doses of drug of plural times of administrations performed in the past, and    the dose comparison circuit compares the dose that is set by the user with a dose that is obtained on the basis of the plural times of administrations performed in the past.    
     
     
         23 . An administration apparatus for medical use as defined in  claim 22  wherein 
 the dose obtained on the basis of the plural times of administrations performed in the past is an average of doses of the plural times of administrations in the past.    
     
     
         24 . An administration apparatus for medical use as defined in  claim 20  further including a notification unit for notifying the user that administration is not possible, when the result of comparison by the dose comparison circuit is equal to or larger than the predetermined value.  
     
     
         25 . An administration apparatus for medical use as defined in  claim 24  wherein 
 when the user permits administration of the dose of drug that is set by the user is permitted after notifying the user that administration is not possible using the notification unit, the control circuit cancels restriction on the operation of the piston rod.    
     
     
         26 . An administration apparatus for medical use which performs administration of a drug using an electric driving source, said apparatus comprising: 
 a drug cartridge having an end closed with a plunger, and containing a drug inside;    a cartridge holder for holding the drug cartridge;    a piston rod for pressing the plunger held in the drug cartridge to move the plunger;    a needle assembly for inserting a needle into a target region, and administering the drug that is emitted from the other end of the drug cartridge with a movement of the piston rod;    a dose setting circuit for setting, by a user, a dose of drug to be administered;    a dose detection circuit for detecting an actual dose of drug using an electronic circuit; and    a comparison detection circuit for comparing the dose that is set by the dose setting circuit with the result of detection by the dose detection circuit to detect overdose or underdose of the drug.    
     
     
         27 . An administration apparatus for medical use as defined in  claim 26  wherein 
 the comparison detection circuit stops the piston rod when it detects overdose of the drug, thereby to stop administration.    
     
     
         28 . An administration apparatus for medical use as defined in  claim 26  wherein 
 the dose detection circuit detects the dose on the basis of the amount of movement of the piston rod.    
     
     
         29 . An administration apparatus for medical use as defined in  claim 26  wherein 
 the dose detection circuit detects the dose on the basis of the time when the piston rod moves at a constant speed.    
     
     
         30 . An administration apparatus for medical use as defined in  claim 17  further including 
 a contact sensor for detecting whether a portion of the administration apparatus in the vicinity of the needle assembly contacts a target region or not,    wherein the air releasing operation is suppressed when the contact sensor contacts the target region.