Poisoning by local anesthetics
Intoxication (poisoning) with local anesthetics can occur, for example, if the drug enters the bloodstream directly instead of into the tissue. The central nervous system can react with restlessness, muscle tremors and cramps, but also dizziness, nausea and vomiting. A metallic taste may appear in the area of the tongue and disturbances of sensation may occur.
If the intoxication is more severe, the heart is weakened and blood pressure drops. The heart rhythm can also slow down, which can lead to circulatory arrest. Allergic reactions rarely occur, especially due to the now rarely used local anaesthetics of the ester type. These can manifest themselves in the form of skin symptoms such as itching and hives, asthma attacks and even anaphylactic shock with circulatory failure.
Local anesthesia at the dentist
At the dentist, most procedures are performed under local anesthesia only. For this purpose, common agents such as lidocaine are used, to which adrenaline is added. Adrenaline prolongs the effect of the local anesthetic and reduces bleeding.
Local anesthesia is suitable for the oral cavity, as here, with the help of less targeted injections, numbness in the treatment area can be achieved. Depending on the treatment, a syringe containing the local anesthetic is inserted into the gums or down to the bone to inject the medication. The anaesthetized nerves and their continuing branches then no longer transmit pain impulses to the brain.
Depending on the type of anaesthetic, the duration of effect and thus freedom from pain is between one and five hours. Apart from a possible short pain during the administration of the injection, patients do not feel any pain during dental procedures. The local anesthetic procaine is also often used in dentistry. Local anesthesia at the dentist, local anesthesia at the dentist,
Local anesthesia for arm and shoulder injuries
For anesthesia of the shoulder and the arms, there are various possibilities of local anesthesia:
- Plexus brachialis anesthesia: The axillary approach in brachial plexus anesthesia (local anesthesia) is the simplest form of anesthesia in the shoulder region. The anesthetic is injected near the artery in the armpit. Since the artery is very easy to palpate, no ultrasound control or nerve stimulation is required.
However, the nerves in this area do not all converge, so a single injection is not sure enough to anaesthetize the entire arm. With this procedure, operations in the area of the lower arm and hand are possible. Contraindications for such a blockage are a pre-damage of the brachial plexus, an inflammation of the lymphatic ducts in this area, as well as a previous breast removal with removal of the lymph nodes.
- Vertical infraclavicular blockage: Another possibility of local anesthesia in this area is the so-called vertical infraclavicular blockage, which also allows interventions on the upper arm.
In this case, a puncture is made below the collarbone. To avoid the risk of lung injury, the puncture is performed under ultrasound control or with the help of a nerve stimulator. Due to the localization, there is also the risk of puncture of the axillary artery.
Since hemostasis is difficult in this case, the patient’s coagulation must not be impaired. Further contraindications are a lung dysfunction as well as paralysis of the phrenic nerve on the other side. This innervates the diaphragm and would lead to respiratory insufficiency in the case of paralysis on both sides, since the diaphragm is the main respiratory muscle.
- Interscale blockade: The third possibility of stunning in this area is the interscale blockade.
Here the puncture site is located above the collarbone and therefore also allows a shoulder operation. Due to the many important arteries and nerves running close by, a precise control of the puncture by ultrasound or nerve stimulation is a prerequisite for the performance of such an anesthesia. These conditions therefore also require the function of the corresponding nerves on the other side.This is because the phrenic nerve can also be paralyzed and thus make breathing impossible.
Also the so-called nervus recurrens runs in this area. It is responsible for the opening of the glottis and leads to hoarseness in cases of unilateral paralysis. However, if the nerve is paralyzed on both sides, the glottis is closed and thus hinders breathing.
A lung dysfunction is also considered a contraindication for such anesthesia. Furthermore, this local anesthesia involves the risk of injection into the vertebral artery, which supplies the brain with blood and can therefore lead to severe toxic reactions and seizures when administered under anesthesia. Similarly dangerous would be an injection into the epidural space or the spinal space.
