Ventilation effect: Increased alveolar ventilation can transport more drugs to the alveoli to compensate for the uptake of drugs by the pulmonary circulation. As a result, the rate of increase in FA (alveolar concentration) and FA/FI is accelerated.

Concentration effect: The concentration of inhaled drugs not only affects the level of FA, but also affects the rate of FA rising. That is, the higher the FI (inhaled drug concentration), the faster FA rises. This phenomenon is called "concentration effect".

Cardiac output (CO): Anesthetics are transferred from the alveoli to the blood by diffusion.

Blood/gas distribution coefficient: refers to the dissolved amount of anesthetic gas in a unit volume of blood when the anesthetic gas and blood reach a state of equilibrium.

The concentration difference of anesthetics in alveoli and venous blood (FA-V): The greater the FA-V, the greater the amount of drug taken up by the pulmonary circulation, that is, the more anesthetics are taken away from the alveoli by the pulmonary blood.

Nitrous oxide (nitrous oxide,): It is a gas anesthetic with weak anesthetic properties. Its MAC (minimum alveolar concentration) is estimated to be 105%.

Sevoflurane: has strong anesthetic properties.

Desflurane (desflurane): has weak anesthetic properties.

Depolarizing muscle relaxants: represented by succinylcholine.

Non-depolarizing muscle relaxants: represented by tubocurarine.

Succinylcholine (Skolin): It is a depolarizing muscle relaxant with a rapid onset of action and complete and short-lived muscle relaxant effect.

Vecuronium (Vacronin): It is a non-depolarizing muscle relaxant with strong muscle relaxant effect, 1 to 1.5 times that of pancuronium, but its action time is shorter.

Rocuronium (Ecoson): It is a non-depolarizing muscle relaxant with a weak muscle relaxant effect, 1/7 that of vecuronium; its action time is 2/3 that of vecuronium, and it is moderately effective. Muscle relaxants.

Cisatracurium: a non-depolarizing muscle relaxant.

①An artificial airway (such as endotracheal intubation or supraglottic ventilation device) should be established and assisted or controlled breathing should be implemented;

② Muscle relaxants have no sedative or analgesic effects and cannot be used alone. They should be used in combination with other general anesthetics;

③The application of succinylcholine can cause a temporary increase in blood potassium, intraocular pressure and intracranial pressure. Therefore, it is contraindicated in patients with severe trauma, burns, paraplegia, glaucoma and elevated intracranial pressure;

④ Hypothermia can prolong the action time of muscle relaxants; inhaled anesthetics, certain antibiotics (such as streptomycin, gentamicin and polymyxin) and magnesium sulfate can enhance the effect of non-depolarizing muscle relaxants. effect;

⑤For patients with neuromuscular junction, such as patients with myasthenia gravis, the use of non-depolarizing muscle relaxants is contraindicated;

⑥Some muscle relaxants have a histamine-releasing effect, and should be used with caution by those with a history of asthma and allergies.

Morphine: An opioid drug extracted from opium.

Pethidine (Meperidine): It has the effects of analgesia, hypnosis and relieving smooth muscle spasm.

Fentanyl: Its effect on the central nervous system is similar to other opioids. Its analgesic effect is 75 to 125 times that of morphine. It lasts for 30 minutes and has an inhibitory effect on breathing.

Remifentanil: an ultra-short-acting analgesic.

Sufentanil: It is a derivative of fentanyl. Its analgesic effect is 5 to 10 times that of the latter, and its duration is approximately twice that of the latter.

Total intravenous anesthesia: refers to the combined application of multiple short-acting intravenous anesthetics after the induction of intravenous anesthesia, and the maintenance of anesthesia by intermittent or continuous intravenous injection.

Intravenous-inhalation combined anesthesia: The depth of total intravenous anesthesia lacks obvious signs, the timing of administration is difficult to grasp, and sometimes the anesthesia can suddenly lighten.

Confirmation method:

Endotracheal intubation may cause damage or loss of teeth, damage to the mucous membranes of the oral cavity, throat and nasal cavity leading to bleeding, and temporomandibular joint dislocation.

Endotracheal intubation under light anesthesia can cause severe choking, breath holding, larynx and bronchial spasm, increased heart rate and severe fluctuations in blood pressure, which can lead to myocardial ischemia or cerebrovascular accidents.

If the inner diameter of the endotracheal tube is too small, the respiratory resistance will increase; if the tube is too soft, it will easily deform, or cause respiratory obstruction due to compression or twisting.

If the catheter is inserted too deep, it may accidentally enter the main bronchus on one side, causing hypoventilation, hypoxia, or postoperative atelectasis.

① Failure of the anesthesia machine and insufficient oxygen supply can cause low inhaled oxygen concentration; insertion of the endotracheal tube into one side of the bronchus or protrusion outside the trachea, as well as respiratory obstruction, can cause hypoxemia, which should be discovered and corrected in time.

②Diffuse hypoxia: can cause nitrous oxide inhalation anesthesia. After stopping inhalation of nitrous oxide, oxygen should be continued for at least 5 to 10 minutes.

③Atelectasis: It can be corrected by suctioning sputum, increasing ventilation and lung recruitment.

④Aspiration: Oxygen therapy is effective in mild cases, and mechanical ventilation should be used in severe cases.

⑤Pulmonary edema: It can occur in acute left heart failure or increased pulmonary capillary permeability. The concentration of inspired oxygen should be increased and the primary disease should be actively treated.

① Excessive anesthesia can cause blood pressure to drop and pulse pressure to become smaller, especially in patients with hypovolemia before anesthesia.

② Excessive blood loss during surgery can cause hypovolemic shock.

③Allergic reactions, adrenal insufficiency, and rewarming can cause a decrease in vascular tone and lead to hypotension. Treatment includes replenishing blood volume, restoring vascular tone (application of vasoconstrictors), and treating the cause.

④Stretching the internal organs during surgery can often cause a reflex drop in blood pressure and bradycardia. The stimulation should be removed promptly and atropine treatment should be given if necessary.

①Related to comorbid diseases, such as essential hypertension, pheochromocytoma, hyperthyroidism, primary aldosteronism, and increased intracranial pressure.

②Related to surgery and anesthesia operations, such as surgical exploration, tracheal intubation, etc.

③Insufficient ventilation causes carbon dioxide retention.

④ Increase in blood pressure caused by drugs, such as ketamine.

Since the nonionic part is lipophilic and easily penetrates tissues, the pKa of local anesthetics can affect:

Influencing factors:

Common reasons:

① The medicinal liquid injected into the tissue must have a certain volume to form tension in the tissue, so that the medicinal liquid is in extensive contact with nerve endings to enhance the anesthesia effect;

② In order to avoid the dosage exceeding the one-time limit, the concentration of the medicinal solution should be reduced;

③Aspirate before each injection to avoid injecting into blood vessels;

④ There is no pain in parenchymal organs and brain tissue, so no injection of medicine is required;

⑤ The concentration of epinephrine in the medicinal solution is 1:200,000 to 1:400,000 (i.e. 2.5 to 5ug/ml), which can slow down the absorption of local anesthetics and prolong the action time.

①It can avoid penetrating into tumor tissue;

② It will not make the operation more difficult because some small lumps are not easily palpable after local infiltration of the medicinal solution;

③The local anatomy of the surgical area will not be difficult to identify due to injection of medicine.

Intercostal groove path: The patient lies on his back with his head turned to the opposite side and his arms next to his body so that his shoulders droop.

Supraclavicular approach: The patient's position is the same as the interscalene approach, but a small thin pillow is placed under the affected shoulder to fully expose the neck.

Axillary approach: The patient lies on his back, abduct the affected limb 90 degrees, and then flex the forearm upward 90 degrees, assuming a military salute posture.

Deep plexus block: There are two commonly used block methods:

Superficial plexus: Same position as above.

complication:

Finger root block: Insert a needle into the dorsal part of the finger root, slide forward through the phalanx and subcutaneously on the palm side. The operator can feel the tip of the needle against the palm side with his finger. At this time, the needle is retreated 0.2 to 0.3 cm, and 1% lidocaine is injected. 1ml.

Intermetacarpal block: The needle is inserted from the back of the hand between the metacarpal bones, directly to the subcutaneous surface of the palm.

① Enter the subarachnoid space of the root through the arachnoid villi and act on the spinal nerve root;

② The medicinal liquid leaks out of the intervertebral foramen and blocks the spinal nerves at the paravertebral level. Because the nerve sheath in the intervertebral foramen is very thin, local anesthetic may penetrate here and act on the spinal nerve root;

③ Directly penetrates the dura mater and arachnoid mater into the subarachnoid space, acting on the spinal nerve roots and spinal cord surface like spinal anesthesia.

①Hypotension: During neuraxial anesthesia, due to the blockade of sympathetic nerves, arterioles dilate, peripheral resistance decreases, venous dilation increases blood volume in the venous system, decreases blood return to the heart, and decreases cardiac output, resulting in hypotension. .

②Bradycardia: Because the sympathetic nerve is blocked, the excitability of the vagus nerve is enhanced, or when the high-level block is performed, the heart accelerating nerve (level above T4) is also blocked, which can slow down the heart rate.

Drop in blood pressure and slowed heart rate: The incidence and severity of drop in blood pressure during spinal anesthesia are closely related to the level of anesthesia.

Respiratory depression: often occurs in patients with high-level spinal anesthesia. Due to extensive thoracic spinal nerve block and intercostal muscle paralysis, the patient feels chest tightness, shortness of breath, difficulty speaking, weakened thoracic breathing, and cyanosis.

Nausea and vomiting: common in

Headache after spinal anesthesia: the incidence rate is 3% to 30%, often occurring 2 to 7 days after anesthesia, and is more common in young women.

Urinary retention: More common.

Neurological complications after spinal anesthesia:

Suppurative meningitis: It can be caused by direct or indirect reasons, such as skin infection, sepsis, etc. Severe cases can be life-threatening, so prevention is important.

① Central nervous system diseases, such as meningitis, anterior horn poliomyelitis, increased intracranial pressure, etc.;

② Coagulation dysfunction;

③Shock;

④Skin infection at the puncture site;

⑤Sepsis;

⑥Spinal trauma or tuberculosis;

⑦Acute heart failure or coronary heart disease attack.

① Resistance disappearance method: During the puncture process, the resistance is small at first, and when it reaches the ligamentum flavum, the resistance increases and there is a sense of toughness.

②Capillary negative pressure method: After the puncture needle reaches the ligamentum flavum, it is connected to the glass capillary tube containing liquid, and the needle continues to be inserted slowly.

Total spinal anesthesia: This is a phenomenon in which most or all of the local anesthetic used for epidural anesthesia is accidentally injected into the subarachnoid space, causing all spinal nerves to be blocked.

Toxic reactions of local anesthetics: There is a rich venous plexus in the epidural space, which absorbs local anesthetics quickly; the catheter can accidentally enter the blood vessel, allowing local anesthetics to be directly injected into the blood vessels; damage to the blood vessels by the catheter can also accelerate the absorption of local anesthetics.

Drop in blood pressure: Mainly due to the blockage of sympathetic nerves, which causes the dilation of resistance blood vessels and capacity blood vessels, leading to a drop in blood pressure.

Respiratory depression: Epidural blockade can affect the movement of the intercostal muscles and diaphragm, leading to a reduction in respiratory reserve function, but has little effect on resting ventilation.

Nausea and vomiting: Same as spinal anesthesia.

Nerve injury: Direct damage to the spinal nerve roots or spinal cord can occur due to puncture needles or harder catheters. The neurotoxicity of local anesthetics should also be considered.

Epidural hematoma: The incidence rate has dropped to 1:500,000 to 1:150,000 in recent years, but we must be vigilant that hematoma formation can cause paraplegia if not treated in time.

Anterior spinal artery syndrome: The anterior spinal artery is a terminal blood vessel that supplies the first 2/3 of the spinal cord cross section. If the blood supply is insufficient for a long time, it will cause spinal cord ischemia or even necrosis and a series of manifestations, called anterior spinal artery syndrome. levy.

Epidural abscess: Because the aseptic operation is not strict, or the puncture needle passes through the infected tissue, the epidural space is infected and an abscess gradually forms.

Difficulty in pulling out or breaking the catheter: The catheter may be difficult to pull out due to ankylosis of the lamina, ligaments and paravertebral muscles.

①Hypovolemia: manifested by dry mucous membranes, increased heart rate, and oliguria.

② Venous return disorder: can occur in mechanical ventilation, tension pneumothorax, cardiac tamponade, etc.

③ Decreased vascular tone: It can occur in neuraxial anesthesia, allergic reactions, adrenal insufficiency, etc., and can also occur when antihypertensive drugs, antiarrhythmic drugs, and rewarming are used.

④ Cardiogenic: including arrhythmia, acute heart failure, myocardial ischemia and pulmonary embolism.

① Postoperative pain, bladder retention, patient restlessness or vomiting.

②Hypoxemia and/or hypercapnia.

③ Increased intracranial pressure, hypothermia or medication errors.

④ There is a history of hypertension in the past, especially when the patient stops taking antihypertensive drugs before surgery.