Extubation during the recovery period from general anesthesia is a critical part of the entire perioperative period.
Due to the stimulation of the nerve endings of the trachea and throat by the tracheal tube and sputum suction tube, and as the patient becomes conscious, the pain of the surgical wound can be gradually perceived.
These factors may activate the body's stress system, causing sympathetic nerve excitation and the release of stress hormones, resulting in a series of drastic hemodynamic changes such as hypertension and tachycardia.
In severe cases, malignant arrhythmia or even cardiac arrest may occur, and serious adverse reactions such as bronchospasm, aspiration, increased intracranial pressure, and bleeding due to increased tension of the surgical wound may occur due to severe coughing and agitation induced during the extubation period.
Affect the patient's rapid postoperative recovery. For the general patients who were previously healthy, self-regulation can be carried out in a short period of time, but for elderly patients, especially those with cardiovascular and cerebrovascular diseases, due to systemic atherosclerosis, the elasticity of blood vessels is reduced.
As a result, the autoregulatory function of blood vessels gradually declines, making the extubation stress response more intense and risky. Therefore, how to effectively prevent or alleviate the stress response, agitation and discomfort caused by extubation during the awakening period of general anesthesia,
It is increasingly valued by clinical anesthesiologists. Stress response is an adaptive mechanism of the body to various stressor stimuli, which requires the participation of multiple systems.
Under normal circumstances, the interaction between the various systems can reach a balance, thus maintaining the stability of the internal environment. When stimulated by an external stressor, the body will activate the stress system, and the stress response produced by the appropriate stimulus intensity is a favorable defense response for the body.
However, if the stimulation is too strong, the overreaction will have a harmful effect on the body. The main causes of stress response during extubation under general anesthesia are: intraoperative intravenous anesthetic propofol and remifentanil, both of which have a short elimination half-life,
After the drug is stopped after the operation, the blood concentration in the patient's body decreases rapidly, so that the depth of anesthesia becomes shallow rapidly, and the patient can perceive the pain of the surgical wound in a short time, coupled with the stimulation of the tracheal tube and sputum suction tube to the nerve endings of the trachea and throat.
Secondly, with the metabolism of analgesics, sedatives and muscle relaxants, the patient's spontaneous breathing gradually recovers, and the airway responsiveness increases, which is also easy to cause serious adverse reactions such as choking cough and even bronchospasm.
At the same time, due to the release of the inhibition of the circulatory system by anesthetic drugs, it can lead to a transient increase in blood pressure, and cardiovascular accidents can occur in severe cases, and with the increase of age, the self-regulation function of the cardiovascular system gradually decays, which is more obvious.
The stress response caused by extubation during the awakening period of general anesthesia has the most obvious impact on the circulatory system, which can activate the sympathetic nervous system, resulting in violent fluctuations in circulatory parameters such as MAP and HR, and an imbalance of myocardial oxygen supply/oxygen consumption.
Myocardial ischemia can lead to serious consequences such as cardiac insufficiency or cardiac arrest. For patients with cardiovascular diseases, the elasticity of blood vessels is weakened, the self-regulatory function of blood vessels gradually declines, and the regulation ability of the autonomic nervous system decreases, which is more likely to lead to damage to the circulatory system.
Studies have found that patients with coronary heart disease and non-cardiac surgery are stimulated by tracheal intubation and extubation, which leads to the activation of the stress system and the enhancement of sympathetic nerve excitability, resulting in an imbalance between myocardial oxygen supply and demand.
As a result, such patients are highly susceptible to myocardial ischemia during anesthesia induction and extubation. Due to the stimulation of the nerve endings of the trachea and throat by the sputum suction tube and tracheal tube, it can induce choking, hoarseness, and edema of the upper respiratory tract tissues.
Serious complications such as laryngospasm or bronchospasm may occur, and aspiration, hypoxemia, or changes in lung function may occur after extubation. For thoracic surgery, single-lung ventilation with a double-lumen bronchial tube is often required.
This kind of catheter is relatively thick and hard, and the process of catheter insertion, intraoperative catheter position adjustment, and postoperative extubation can produce strong stimulation to the throat area, trachea and bronchi, and the above complications are more likely to occur.
Withdrawal of the endotracheal tube often results in increased intracranial and intraocular pressure, increased cerebral oxygen consumption, and may have deleterious effects in patients with cranial lesions.
However, for patients with head trauma undergoing surgery, the injury factors themselves and the stimuli of various operations during the extubation period produce a stress response, resulting in the release of a large number of toxic excitatory neurotransmitters and inflammatory factors, which can lead to secondary damage.
During the extubation period, the sympathetic-adrenomedullary axis is first activated, resulting in an increase in the secretion of catecholamine hormones, followed by the activation of the hypothalamic-pituitary-adrenocortical axis, resulting in an increase in cortisol secretion.
A large number of inflammatory factors produced by stress can cause insulin resistance, and at the same time, the level of catecholamines caused by stress increases, and the utilization rate of insulin in peripheral tissues decreases, so that the body is in a state of hyperglycemia.
The greater the trauma of the operation and the stronger the various stimuli during extubation, the more significant the increase in blood glucose levels. On how to effectively alleviate the stress response, agitation and discomfort caused by extubation during the recovery period of general anesthesia,
Scholars at home and abroad have used a variety of methods, and have achieved certain results. In recent years, scholars at home and abroad often control hemodynamic changes during extubation under general anesthesia by intravenous or endotracheal injection of lidocaine.
Intratracheal injection of 2% lidocaine can effectively reduce the choking reaction caused by extubation, and the circulatory parameters such as MAP and HR before and after extubation fluctuate less, and the level of stress hormones is also more stable than that of the control group.
The reason for this effect may be related to the fact that the local anesthetic effect of lidocaine directly blocks the site of initiation of the stress reflex arc (receptors).
Intravenous lidocaine can also suppress cough and maintain circulatory stability, but the duration of action is shorter and the effect is far less than that of topical endotracheal lidocaine.
It is reported that sufentanil has the strongest analgesic effect among the fentanyl group in clinical practice, has a certain inhibitory effect on circulation and respiration, and there is a dose-response relationship, and is widely used in general anesthesia induction and postoperative recovery period.
Some scholars have reported that intraoperative targeted infusion of sufentanil can effectively inhibit the cyclic fluctuations in the induction and extubation phases, but with the increase of dose, the inhibition effect becomes more obvious, and it may prolong the postoperative eye opening and extubation time, and even post-extubation respiratory depression occurs.
In elderly patients, the organ reserve function is reduced, and large doses of sufentanil may cause large fluctuations in circulation, so care should be taken to choose small doses when applying.
The latest research has confirmed that dezocine mainly stimulates kappa and μ1 receptors, produces analgesic effects, and can also inhibit the reabsorption of norepinephrine and serotonin, exerting a unique analgesic effect.
Because it does not infuse μ2 receptors, the incidence of adverse reactions such as respiratory depression, gastrointestinal reactions, and drug dependence is low. Studies have shown that the effect of dezocine advanced analgesia is clear, and it can effectively prevent central sensitization caused by stress stimuli.
The physicians observed the effect of dezocine advanced analgesia in elderly patients during the recovery period of anesthesia, and the results showed that the advanced analgesia of dezocine could not only maintain the stability of circulation during the recovery period, but also improve the perioperative safety of elderly patients, but it was also dose-related.
Pay attention to choosing the appropriate dosage when applying. The opioid agonist antagonist butorphanol has good analgesic effect, good sedative effect, mild respiratory depression and low drug dependence, and can effectively prevent perioperative agitation in patients with general anesthesia.
The study found that 20 μg/kg butorphanol for patients with hypertension significantly reduced the stress response during extubation and reduced the incidence of cardiovascular accidents.
According to reports, when slowly intravenous injection of 30 μg/kg butorphanol, patients after extubation are prone to drowsiness, respiratory depression, etc., which is aimed at young and middle-aged patients, while the elderly have increased sensitivity to the drug, and attention should be paid to reducing the dose when applying butorphanol.
In order to eliminate the adverse memories caused by extubation, the patient needs to have some sedation and brief amnesia during extubation. Propofol is a widely used sedative anesthetic in clinical practice, which has the advantages of rapid onset, rapid awakening, and low incidence of gastrointestinal reactions such as nausea and vomiting.
According to reports, the targeted infusion of sedative dose of 1 μg/ml propofol to 5 minutes after extubation can effectively inhibit the extubation reaction, do not prolong the extubation time, and have almost no inhibitory effect on respiration and circulation.
At the same time, because propofol has the advantage of anterograde amnesia, it is helpful to eliminate the bad memory caused by extubation. In recent years, a number of scholars have conducted a lot of research on dexmedetomidine.
Studies have found that compared with clonidine, dexmedetomidine is more selective for α2-adrenergic receptors, has the effect of inhibiting sympathetic, maintaining circulatory stability, and can reduce the occurrence of perioperative cardiovascular accidents, so it has been widely used in clinical practice.
Some scholars have reported that intravenous injection of 0.4 μg/kg dexmedetomidine 5 minutes before surgery can reduce the airway circulatory reflex during extubation. 0.2 μg/kg dexmedetomidine alone is not fully effective in controlling cyclic fluctuations during extubation.
The reason may be that the analgesic effect is insufficient, and the application of dexmedetomidine combined with dezosine to observe the quality of recovery in elderly patients shows that the effect of the combined group is significantly better than that of the dexmedetomidine group alone.
At present, short-acting antihypertensive drugs used in the extubation period of general anesthesia are more and more favored by anesthesiologists, and esmolol is an ultra-short-acting antihypertensive drug that is widely used in clinical practice.
Studies have found that esmolol 1.5mg/kg 2 minutes before extubation can effectively alleviate or eliminate the cardiovascular response caused by extubation, and can reduce myocardial oxygen consumption, and has few side effects, but esmolol cannot inhibit the activity of sympathetic nerves.
Urapidil, an α1-adrenergic receptor antagonist and 5-HT1A receptor agonist, is an antihypertensive drug with a dual mechanism of action of peripheral and central, and is commonly used to prevent cardiovascular response caused by extubation during general anesthesia recovery.
It was found that intravenous injection of 0.25~0.5mg/kg urapidil before the patient woke up could effectively inhibit the increase in blood pressure and heart rate during extubation in hypertensive patients, and it was dose-dependent.
However, there was no significant difference in the plasma concentrations of NE and Cor before and after extubation compared with the control group, indicating that urapidil had no obvious inhibitory effect on the stress response caused by extubation.
Nicardipine, the first dihydropyridine calcium channel blocker that can be administered intravenously, lowers blood pressure by regulating intracellular Ca2+ levels and dilating blood vessels, but nicardipine does not control the heart rate increase during extubation well.
Studies have confirmed that esmolol can effectively inhibit the rapid heart rate response caused by stress and reduce myocardial oxygen consumption. Therefore, some scholars have combined the two drugs of nicardipine and esmolol,
It can effectively prevent hemodynamic fluctuations caused by extubation and improve the quality of patient recovery. In recent years, some scholars have tended to use the two drugs in combination to prevent stress during extubation.
It can not only make up for the shortcomings of the pharmacological effect of a single drug, but also reduce the dose and side effects of each drug. For example, dexmedetomidine is often used in combination with opioids because dexmedetomidine inhibits stress and has a minimal effect on the respiratory system.
However, the analgesic effect is weaker than that of opioids, while opioids have a stronger analgesic effect, but respiratory depression often occurs.
It also reduces the incidence of side effects during single medication, which can better stabilize the hemodynamics during extubation and prevent stress responses, thereby improving the quality of patients' recovery.
The advantages of extubation under deep anesthesia are that it can reduce the choking caused by stimuli such as sputum suction tubes and tracheal tubes, relieve agitation during the awakening period, and better inhibit the stress response caused by extubation, but it will inevitably increase the incidence of reflux aspiration, respiratory obstruction and respiratory depression.
Propofol and sevoflurane, which are commonly used for extubation under deep anesthesia, have been shown to be effective in inhibiting cardiovascular responses during extubation, but patients treated with sevoflurane have a longer recovery time than those treated with propofol.
Extubation during the awakening period of general anesthesia is a key part of the perioperative period, and the stress response caused by extubation is inevitable, and there is no unified standard for how to comprehensively suppress the stress response during extubation.
Each drug has its own characteristics and defects, and anesthesiologists should combine the specific situation of the patient and the pharmacological effects of the drug to formulate a reasonable medication plan when choosing a drug to prevent stress.
The use of sedative drugs may prolong the patient's awakening time, and with the increase of the dose, the risk of tongue fall or even airway obstruction may occur;
Some sedative and analgesic drugs have respiratory depression, and attention should be paid to closely observing the patient's breathing during application, and the effect of antihypertensive drugs on patients' circulatory parameters such as MAP and HR is dose-related.
During application, the hemodynamic changes of patients should be closely observed to prevent serious complications caused by drug overdose, and the sensitivity of elderly patients to drugs should be enhanced, and more attention should be paid to the dosage of drugs.
Scholars at home and abroad have reported a variety of programs to prevent stress during extubation, and have achieved certain results, and by summarizing a variety of programs, it provides more ideas for further research to solve this problem.