|Title of Invention||
A DEVICE FOR REDUCING THE DOSE OF LOCAL ANAESTHETIC DRUG IN AXILLARY BLOCK
|Abstract||ABSTRACT A device has been fabricated for reducing the dose of local anaesthetic drugs necessary for axillary (Axilla-armpit) block anaesthesia. The conventional procedure for axillary block anaesthesia consumes near maximal dose of local anaesthetic drug. The present device helps in bringing down the dose of the drug. Reduction of the dose of local anaesthetic drug brings downs the chance of toxicity due to over dosage. This facilitates repeat use of the drug and also use of additional drug for simualtaneous operation at other sites of the body. The reduced dose also lessens the cost of anaesthesia.|
|Full Text||THE PATENT ACT, 1970
FORM - 3 A
A DEVICE FOR REDUCING THE DOSE OF LOCAL ANAESTHETIC DRUG
(j)IN AXILLARY BLOCK
Dr. Satyanarayan Mishra
342,1st Main Road,
Annamalai nagar 608-002
(An Indian Citizen)
The following specification particularly describes and ascertains the nature of this
invention and the manner in which it is to be performed.
Anaesthesia (Loss of Sensation) is of several types viz.
A) General - The whole body is anaesthetized
B) Regional i) Spinal/Epidural - Only lower limb is anaesthetized.
ii) Peripheral nerve block - Areas supplied by the particular
nerves get anaesthetized.
C) Local i) Infiltration:- Local anaesthetic drug is injected into the area
to be anesthetized.
ii) Topical:- Anaesthetic drug is applied over the skin/mucosa
of the area to be oberated. Upper limb (Hand, forearm and arm) can be effectively operated by peripheral nerve block. The nerves supplying the upper limb are from a nerve plexus called brachial plexus. These nerves along with the axillary artery, the main artery supplying blood to the upper limb, have a covering called axillary sheath during their course from the neck to the arm. The nerves lie around the artery. If the local anaesthetic drug is injected inside the axillary sheath, it remains there for sometime without spreading to surrounding tissue. This allows sufficient local concentration and sufficient time for contact of the drug with the nerves blocking the passage of sensation producing anaesthesia of the upperlimb.
But the drug solution spreads within the axillary sheath both upwards towards the neck and downwords toward the arm. For this reason large volume of local anaesthetic solution becomes necessary for ensuring an effective axillary
block. This plexus can be blocked at several levels viz. interscalene, supraclavicular, infraclavicular and axillary. When blocked at the level of axilla (arm pit) this is called axillary block, which is commonly used while performing surgery on hand and forearm. Also, the axillary block is the safest among brachial plexus blocks. Toxicity of local anaesthetic drugs are due to
i) Excessive dosage
ii) Accidental injection into a blood vessel. The maximum permissible dose of the commonly used local anaesthetic drugs are thus
Plain lignocaine - 3.5mg/Kg Body wt Lignocaine with adrenaline - 7mg/Kg Body wt Bupivacaine - 2mg/Kg Body wt
The minimum concentration necessary for a nerve block is 1% Lignocaine, and 0.25% bupivacaine.
Example:- Maximum permissible does of 1% lignocaine with adenaline for a 60kg adult is
60x7x100/1000 = 42ml For safety, always minimum amount of local anaesthetic drug should be used A combination of lignocaine and bupivacaine solution can also be used In a conventional method of axillary block the patient lies supine (flat). The arm is abducted and externally rotated; the elbow flexed with the palm facing up and
lying by the side of the head.The axillary artery is palpated. 30-50ml of 1% local anaesthetic solution is injected by single or multiple injections into the axillary sheath around the axillary artery. Sometimes a light tourniquet is applied on the upper arm to compress the axillary sheath, which in turn prevents the escape of local anaesthetic solution downwards (distally). This allows high concentration of local anaesthetic drug in the axillary sheath for successful nerve block. The axillary block consumes almost the maximum permissible dose of local anaesthetic drug. This has got following disadvantages.
i) If the block fails it can not be repeated forthwith because toxicity can
occur due to excessive dosage, ii) If simultaneous operation is necessary at another site on the same patient, it cannot be done using additional local anaesthetic since excessive dosage will cause toxicity, iii) It does not prevent the escape of local anaesthetic solution upwards within the axillary sheath. Statement of the invention
The present invention relates to a device for reducing the dose of local anaesthetic drug in axillary block; the said device consisting of a circular ring; the said ring made of solid stainless steel with uniform circular cross section; the said ring having two collars fixed to its top on opposite sides; the said collars being inverted CC5 shaped; the said collars being made of solid stainless steel with uniform circular cross section.
Method of Manufacture
The solid stainless steel rod is bent in a circular fashion and welded to complete the ring. The stainless steel rod meant for the collar is bent into a fiC form, inverted and welded to the ring. If necessary, the whole thing can be cast in a die. Method of using the device
The patient is positioned as in a conventional axillary block. One 21 size hypodermic needle is inserted into the axillary sheath on each side of the axillary artery. Total 20ml (10ml through each needle) of local anaesthetic solution is injected and the needles are withdrawn. The ring is applied over the skin encircling the injection sites and pressure is applied on the ring by vertically pressing on the collars, which distributes the force on the ring. This pressure on the ring is transmitted to the axillary sheath sealing it on all sides which prevents escape of anaesthetic solution on all sides and confines it to the area inside the ring. The skin inside the ring is massaged to allow fast passage of anaesthetic solution around the nerves within the confines of the ring.
High concentration of anaesthetic drug is maintained around the nerves and anaethesia of upper limb sets in despite lower dosage of the drug.
The advantage of using this device over the conventional method are:
1. If necessary, the block can be repeated without the chance of dose related toxicity.
2. Simultaneous operation on another site on the body can be performed using local anaesthetic drug without the fear of toxisity
3. The cost of drug per individual patient also comes down.
It is to be understood that the present invention is by no means limited to the particular construction herein disclosed and shown in the drawings, but also comprises any modification or equivalants within the scope of the disclosure.
The device will be described through the figures in the only accompanying drawing sheet. A is the ring; Bi and B2 are the collars. Fig 1 is the top view; Fig.2 is the side view; and Fig 3 is the bottom view.
1. A device for reducing the dose of local anaesthetic drug in axillary block;
the said device consisting of a circular ring; the said ring made of solid
stainless steel with uniform circular cross section; the said ring having two
collars fixed to it's top on opposite sides; the said collars being inverted 'C
shaped; the said collars being made of solid stainless steel with uniform
circular cross section.
2. The device as in claim 1 wherein the said ring is of oval shape
3. The device as in claims 1 and 2 wherein the ring is made of hollow tube.
4. The device as in claims 1 to 3 wherein the ring is having a soft coating on it.
5. The device as in claims 1 to 4 wherein the whole device can be fabricated
in a single die cast.
6. A device for reducing the dose of local anaesthetic drug in axillary block
substantially as herein described with particular reference to the figures in
the accompanying drawings.
|Indian Patent Application Number||725/CHE/2007|
|PG Journal Number||38/2013|
|Date of Filing||05-Apr-2007|
|Name of Patentee||DR. SATYANARAYAN MISHRA|
|Applicant Address||AN INDIAN NATIONAL RESEDINGAT 342, 1ST MAIN ROAD, MARIAPPA NAGAR, ANNAMALAI NAGAR-608002, INDIA|
|PCT International Classification Number||A61B17/02|
|PCT International Application Number||N/A|
|PCT International Filing date|