BASIC LEVEL - LOCAL ANESTHESIA AND NURSING

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Anesthesia nursing column

BASIC LEVEL - LOCAL ANESTHESIA AND NURSING

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Read Book Sources:

Basic Nursing Technology and Specialty Nursing Practice(2020.
08)

Author: Lei Ying, editor-in-chief

Tidy up:

School of Nursing, Xuzhou Medical University, Yang Tingting

Department of Anesthesiology, Beijing Tsinghua Chang Gung Hospital Tu Shumin

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First, commonly used local anesthetics

(1) According to the different chemical structure, it is divided into esters and amides:

● Ester local anesthetics include procaine, cloprocaine, tetracaine and cocaine;

● Amide local anesthetics such as docaine, bupivacaine, epticaine and ropivacaine
.

(2) According to the maintenance time of local anesthetic, it is divided into short-acting local anesthetic, medium-acting local anesthetic and long-acting local anesthetic.

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Second, commonly used local anesthesia methods:

Surface anesthesia, local infiltration anesthesia, regional blocks, intravenous local anesthesia, and nerve blocks
.

(1) Surface anesthesia: The local anesthetic with strong osmotic properties is in contact with the local mucosa, and the local anesthetic effect caused by penetrating the mucosa and acting on the nerve endings is called surface anesthesia
.

(1) Commonly used drugs: lidocaine, tetracaine
.

(2) Anesthesia method:

●Ocular surface anesthesia, mostly by instillation;

●The mucous membrane in the nasal cavity is often filled with cotton tablets;

●The pharyngeal and endotracheal mucosa is sprayed, and the intraurethral mucosal surface anesthesia is used for perfusion
.

(2) Local infiltration anesthesia: local anesthetics is injected in layers along the surgical incision line to block nerve endings
in tissues.

(3) Area block: inject local anesthetics around the perimeter and bottom of the surgical area to block the nerve trunk and nerve endings
entering the surgical area.

(4) Intravenous local anesthesia: a method of
injecting local anesthetic into the vein after ligating the tourniquet on the limb, so that the distal limb of the tourniquet can be anesthesized.

(5) Nerve block: refers to the anesthesia method
by which anesthetics are injected into or around the nerve/ganglion tissue to allow anesthesia to penetrate into the nerve tissue.

(6) Nursing

(1) General care:

● Local anesthetics have little impact on the body and generally do not require special care;

● Outpatient surgeons who use a lot of medication during the operation and have a long operation process should rest for a while after surgery, and can leave the hospital only after observing that there is no abnormality, and tell the patient to seek medical treatment
immediately if he is unwell.

(2) Adverse reactions and care of local anesthesia drugs:

●Adverse effects of local anesthetics include local and systemic
.

● Local adverse reactions: mostly caused by direct contact between local anesthetics and tissues, if the concentration of local anesthetics is high or contact with the nerve for too long can cause nerve damage, so the medication must follow the principle of
minimum effective dose and minimum effective concentration.

●Systemic adverse effects: including hypersensitivity, allergy, central neurotoxicity, and cardiotoxicity
.
Toxic reactions occur with small doses of local anesthetics, and hypersensitivity reactions
should be suspected.
As soon as it occurs, the drug is discontinued immediately and actively treated
.

●The vast majority of patients allergic to local anesthetics are allergic to esters, and conjunctiva, intradermal injection, or basophil degranulation testing
may be used for those suspected of allergic reactions.

● Central toxicity is manifested as numbness of the tongue or lips, headache, dizziness, tinnitus, blurred vision, nystagmus, slurred speech, muscle twitching, incoherence, confusion, convulsions, coma, and respiratory arrest; Cardiovascular toxicity manifests as decreased myocardial contractility, slowed conduction velocity, and peripheral vasodilation
.

●The key is prevention, and the injection of local anesthetics must be repeated before repeated "retraction tests" to confirm that there is no gas, no blood, and no cerebrospinal fluid
.

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3.
Neuraxial anesthesia

There are two cavities in the spinal canal that can be used for anesthesia, the subarachnoid space and the epidural space, and local anesthetic can be injected into these spaces to produce lower body or partial anesthesia
.
According to the different cavities injected by local anesthetics, it is divided into subarachnoid block (referred to as lumbar anesthesia), epidural block and lumbar anesthesia-epidural joint block, collectively known as spinal anesthesia
.

During neuraxial anesthesia, the patient is conscious, the analgesic effect is accurate, the muscle relaxation is good, but there is a certain disturbance to the physiological function, and it can not completely eliminate the visceral traction response Subarachnoid block, referred to as spinal anesthesia, is to inject local anesthetic into the subarachnoid space, so that the spinal nerve root, root ganglia and spinal cord surface part produce different degrees of blockage, the main action site is in the anterior and posterior roots
of the spinal nerve root.
The incidence of serious neurological complications or sequelae of spinal anesthesia is no higher than that of other anesthesia methods, and it is still the most commonly used anesthesia method
in lower limb and lower abdominal surgery.

(1) Classification

(1) Classification according to the plane of spinal nerve block:

(1) High-plane spinal anesthesia: the plane of spinal nerve block exceeds the thoracic plate.

Nerves below the thoracic 2 nerve, suitable for epigastric surgery, but often with respiratory and circulatory depression, must be prepared for first aid when applying; If the block plane exceeds thoracic 2, breathing and cardiac arrest may occur at any time, and clinical use is rare;

(2) Low-plane spinal anesthesia: the spinal nerve block plane is below thoracic 10, which has no effect on breathing and circulation, and is suitable for groin and lower limb surgery;

(3) Saddle anesthesia: only the sacrococcygeal nerve is blocked, suitable for anal and perineal surgery
.

(1) Classification according to the mode of administration:

(1) Unilateral spinal anesthesia: refers to the blockage of the spinal nerve root on one side, but in fact it is not limited to one side, but the plane of blockade on both sides is asymmetrical; If the side is taken in the decubitus position, the diseased side is in the lower position, the weight specific gravity solution is used, and the puncture needle is obliquely facing downward when injecting the drug, so that the blockade plane of the diseased side is higher than the healthy side, and the action time is also longer than that of the healthy side;

(2) Continuous spinal anesthesia: After puncture, the catheter is inserted into the subarachnoid space and administered in divided doses to maintain long-term spinal nerve block.

(2) Commonly used anesthetics: The more commonly used local anesthetics for subarachnoid block are procaine, tetracaine, bupivacaine and ropivacaine
.

(3) Factors affecting the plane of subarachnoid block: puncture gap, patient position, age, intra-abdominal pressure, body temperature, nature of the anesthetic, dose, concentration, volume, specific gravity, injection speed and needle tip inclined direction, etc
.

(4) Classification

1.
High epidural block: puncture between neck 5 and thoracic 6 to block the spinal nerves
of the neck and upper thoracic segment.
High epidural block is prone to serious complications and anesthesia accidents, and is rarely used
clinically from a safety point of view.

2.
Median epidural block: the puncture site is from chest 6 to thoracic 12
.

3.
Low epidural block: the puncture site is in the gap
of each spinous process in the waist.

4.
Sacral block: puncture through the sacral hiatus to block the sacral nerve
.

(5) Commonly used anesthetics: local anesthetics used for epidural block should have the characteristics of strong penetration and diffusion, small toxic adverse reactions, short onset of action and long action time, and the most commonly used clinical drugs are lidocaine, tetracaine and bupivacaine
.

(6) Factors affecting epidural block

(1) Drug volume and injection speed: the larger the drug volume, the faster the injection speed, and the wider
the level and range of sensory block.
Divided doses can enhance the blocking effect
.

(2) Catheter position and direction: When the catheter is inserted into the tip, the drug is easy to spread to the tip; When inserted towards the caudal end, it spreads in multiple directions to the caudal end; The catheter is biased to one side and unilateral anesthesia
may occur.
However, it is still the location of the catheter orifice that ultimately determines the direction of drug diffusion;

(3) Pregnancy: In the late stage of pregnancy, due to the compression of the inferior vena cava, the epidural space vein is filled, the gap is relatively small, and the amount of medication is reduced;

(4) Hypocoagulable state: easy to cause epidural hemorrhage, epidural hematoma
.

(7) Nursing

1.
General care

(1) Body position: In order to prevent headache after anesthesia, it is customary to go to the pillow to lie flat for 6 ~ 8 h
.

(2) Condition observation: closely monitor vital signs to prevent complications after anesthesia
.

(3) Psychological care: do a detailed job of explanation, introduce the process of anesthesia and necessary cooperation to patients, and alleviate their anxiety and fear
.

2.
Prevention and care of common complications

1) Subarachnoid block:

(1) Hypotension: caused by
sympathetic nerve block.
Prevention and control measures: speed up infusion, increase blood volume; If blood pressure drops sharply, ephedrine 15 ~ 30mg intravenously can be injected intravenously to constrict blood vessels and maintain blood pressure
.

(2) Nausea and vomiting: caused
by hypotension, vagus nerve hyperfunction, surgical traction of internal organs and other factors.
Prevention measures: oxygen, pressor, suspension of surgery to reduce vagus irritation, if necessary, metoclopramide 10 mg
intravenously.

(3) Respiratory depression: common in thoracic spinal nerve block, manifested as intercostal muscle paralysis, chest breathing weakening, tidal volume reduction, cough weakness, and even cyanosis
.
Prevention and control measures: cautious medication, oxygen inhalation, circulation maintenance, tracheal intubation in case of emergency, artificial respiration
.

(4) Headache: The incidence is 3% ~ 30%, mainly due to the penetration of the dura and arachnoid during lumbar puncture, resulting in
cerebrospinal fluid loss, intracranial pressure drop, and intracranial vasodilation stimulation.
Typical headache can occur 6 ~ 12h after puncture, when the patient raises his head or gets up for the first time after surgery, the pain is often located in the occipital, top or temporal area, pulsating, and aggravated
when raising the head or sitting up.
About 75% of patients disappear symptoms within 4 days, most of them do not exceed 1 week, but the course of disease in individual patients can be as long as more than
half a year.
Prevention: When visiting patients before anesthesia, do not suggest the possibility of headache after subarachnoid block; During anesthesia, fine puncture is used to avoid repeated punctures, improve puncture techniques, reduce needle puncture holes, and ensure sufficient fluid
infusion during and after surgery.

(5) Urinary retention: mainly caused by the late recovery of the 2nd, 3rd and 4th sacral nerves that innervate the bladder after being blocked, the pain of the incision after surgery in the lower abdomen, anus or perineum, the direct stimulation of the bladder during lower abdominal surgery, and the patient's unaccustomed to urinating in bed
.
Generally, acupuncture points such as foot Sanli, Sanyin sex, Yanglingquan, Guan Yuan and Zhongji, or hot compresses to the lower abdomen and bladder area can help relieve urinary retention
.

2) Epidural block:

(1) Total spinal anesthesia: the most dangerous complication of epidural anesthesia, when the puncture needle or catheter is mistakenly inserted into the subarachnoid space during epidural block, it is not detected in time, resulting in excessive local anesthetic injection into the subarachnoid space and abnormally extensive block.

● If not detected and properly treated in time, cardiac arrest
can occur.

● Once total spinal anesthesia is suspected, positive pressure ventilation should be performed immediately, and if necessary, tracheal intubation should be performed to maintain breathing, speed up the infusion rate, and give vasopressors to maintain circulatory function
.

● Prevention: Routine preparation of anesthesia machine and tracheal intubation equipment before anesthesia, meticulous and careful puncture operation, first withdraw before injection, observe whether there is cerebrospinal fluid, first use the test dose (3 ~ 5 mL) and observe 5 ~ 10 min during injection, and inject the test dose again after changing the position to re-examine, effectively preventing the patient from restlessness
during surgery.

(2) Puncture needle or catheter mistakenly into the blood vessel: the incidence rate is 0.
2% ~ 2.
8%.

Epidural space veins in full-term pregnancies are distended and are more likely to pierce the blood vessels, so they must be withdrawn
before injection.
Check for return of the extramembrane catheter
.
Once the local anesthetic is injected directly into the blood vessels, toxic reactions will occur, convulsions or cardiovascular symptoms
will occur.
The principle of treatment is oxygen, intravenous diazepam, or thiopental sodium to control seizures while maintaining ventilation and effective circulation
.

(3) Catheter breakage: It is one of the common complications of epidural block, mostly caused by poor catheter placement technology, poor catheter texture, local compression of catheter, improper extubation, too deep catheter or catheter circle
.
Prevention: Standardize the puncture technique, once the tip of the catheter crosses the slope of the puncture needle and cannot continue to enter, the puncture needle should be pulled out together with the catheter, and punctured separately, and excessive force
should not be used during extubation.

(4) Epidural space hemorrhage, hematoma and paraplegia: If the blood vessels are damaged during epidural puncture and catheterization, bleeding can be caused, and hematoma compressing the spinal cord can be complicated by paraplegia
.
CT or MRI can confirm the diagnosis and localization
.
An epidural aspiration should be performed as soon as possible to remove blood and, if necessary, an incision of the lamina to remove the hematoma
.
Prevention: Epidural block anesthesia is contraindicated for patients with coagulation dysfunction or during anticoagulant therapy, and the catheter placement should be delicate and gentle
.

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Article | Tu Shumin

Typography | meat