The mechanism of action of local anesthetics:
Promote Na+ flowing inward, producing a persistent depolarization.
Specifically blocks Na* channels of nerve cell membranes, impeding depolarization.
Promote K+ inward flow, impeding depolarization.
Reduce membrane permeability to Na+, K+, and Ca2+.
Bind to extracellular Na+, preventing Na+ inward flow during depolarization.
When an interscalene block is used, the most common block incompletion is:
Radial nerve
Median nerve
Ulnar nerve
Median nerve and radial nerve
Radial nerve and ulnar nerve
Factors affecting the action of local anesthetics do NOT include:
Site of injection
pH of body fluid
Concentration of the anesthetics
Function of the liver
Using of the vasoconstrictors
To prolong the duration of action of local anesthetics and reduce absorption, the recommended measure is:
Increasing the dosage of local anesthetics
Increasing the concentration of the local anesthetics
Adding a small amount of norepinephrine
Adding a small amount of epinephrine
Adjusting the PH of the drug to weak acidity
The reason procaine is not suitable for surface anesthesia is：
High irritation
High toxicity
Weak penetration
High diffusion
Effect of local vasodilatory
The most likely cause of hoarseness or loss of voice in a patient with cervical plexus nerve block is:
Toxic reaction to local anaesthetics
Recurrent laryngeal nerve block
Vagus nerve block
Phrenic nerve block
Anesthetics mistakenly entering the epidural space
The most common complication of subarachnoid anesthesia：
Retention of urine
Syndrome of cauda equina
Headache
Nausea and vomiting
Myelitis
The patient is most likely to present:
Total spinal anesthesia
Local anesthetic toxicity
Cerebrovascular accident
Hypersensitivity to local anesthetics
Respiratory depression
The most likely cause of this complication is:
Overdose of medication
Drug absorption rate is too fast
Rich blood supply at the injection site
Accidental vascular injection of local anesthetics
The patient has poor tolerance to anesthetics
Measures to avoid the above complications in this patient:
Controlling the drug dose
Slowing the rate of injection
Reducing the concentration of the drug
Withdrawing the drug before injection
Improving the patient's tolerance