High blood pressure after surgery. Pressure during anesthesia Increased pressure after anesthesia rhinoplasty

Arterial hypertension occurs in 25% of patients undergoing surgery. A pronounced increase in blood pressure is fraught with the development of ischemia or myocardial infarction, arrhythmia, heart failure, pulmonary edema, increased intraoperative blood loss, ruptured vascular sutures, increased intracranial pressure, hypertensive encephalopathy, or intracerebral hemorrhage.

When collecting an anamnesis, the severity and duration of arterial hypertension are revealed. It is believed that hypertension of the first and second stages does not increase the risk of complications in the perioperative period (systolic blood pressure does not exceed 180 mm Hg, and diastolic blood pressure is below 110 mm Hg). Clarify the presence and severity of pathological changes that accompany hypertension and increase the risk of complications: pathology of the kidneys, the presence of coronary artery disease, heart failure, myocardial infarction, a history of cerebrovascular accident, damage to the organs of vision. Pay attention to the pathology of the kidneys, adrenal glands, thyroid gland, excluding the secondary nature of hypertension. Find out what antihypertensive drugs the patient is using. Central?-agonists (clophelin),?-blockers can cause a rebound symptom when they are canceled. In addition, central agonists have a sedative effect and reduce the need for anesthetics. Diuretics, often prescribed to such patients, contribute to the development of electrolyte disorders, in particular hypokalemia, and potassium-sparing diuretics (spironolactone, triamterene) - hyperkalemia. These drugs deliberately reduce the volume of circulating blood, which, without adequate fluid therapy, can be the cause of severe hypotension, especially during the induction of anesthesia. There is evidence that angiotensin-converting enzyme blockers, in particular captopril, sometimes cause difficult-to-correct hypotension and hyperkalemia. The use of?-blockers contributes to the occurrence of bradycardia, AV blockade, decreased myocardial tone, increased bronchial tone, and depression.

Bradycardia, myocardial depression with the use of?-blockers during anesthesia is usually well corrected with atropine, calcium chloride, in rare cases it becomes necessary to use adrenomimetics

Undesirable consequences of taking calcium channel blockers (verapamil, diltiazem) are a decrease in myocardial contractility, bradycardia, conduction disturbances, and potentiation of the action of non-depolarizing muscle relaxants.

During a physical examination, the boundaries of the heart are determined in order to clarify the severity of ventricular hypertrophy. During auscultation, a presystolic gallop rhythm is often heard, associated with severe left ventricular hypertrophy. With the development of heart failure, wheezing in the lungs, a protodiastolic gallop rhythm are determined. Pay attention to the presence of peripheral edema (a manifestation of heart or kidney failure), signs of hypovolemia are possible: dry skin, tongue. Measurement of blood pressure, if possible, is carried out in a supine and standing position.

If organ changes are not expressed (hypertension stage I, II), conventional laboratory and instrumental studies are carried out. Pay attention to the level of blood electrolytes, creatinine, the presence of proteinuria, electrocardiographic changes, chest x-ray (in order to determine the degree of left ventricular hypertrophy).

If there are functional changes in the internal organs, their severity should be clarified. To do this, studies of the functional state of the cardiovascular system are carried out: ECG with stress tests, IRGT with a test for exercise tolerance, Echo-KG, which often reveals changes that are invisible during ECG and X-ray studies. If during the preliminary examination there is a suspicion of the presence of renal failure, an in-depth examination of kidney function is performed, including the determination of the glomerular filtration rate, ultrasound of the kidneys, etc. In patients with previously undiagnosed hypertension, the duration and severity of the process can be judged by the degree of changes in the fundus. Most often, the Keith-Wagner classification is used, which provides for the division of patients into 4 groups: 1) constriction of retinal arterioles. 2) constriction and sclerosis of retinal arterioles. 3) hemorrhages and exudate in addition to the first two signs. 4) edema of the optic nerve papilla (malignant hypertension).

Relative contraindications for elective surgery are diastolic pressure above 110 mm Hg. Art. especially in combination with damage to target organs (heart, kidneys, central nervous system). In such cases, drug correction of hypertension should be carried out.

In the preoperative period, patients, as a rule, continue to take antihypertensive drugs according to the usual scheme. In order to reduce feelings of anxiety, fear and, consequently, hemodynamic changes, sedatives are prescribed immediately before surgery. Benzodiazepines are most often included in premedication, neuroleptics, central ?-agonists are used according to indications. In patients with arterial hypertension, ganglionic blockers (arfonad, pentamine) are widely used. It is possible to use the following technique: before surgery, the patient's blood pressure response to intravenous administration of hexonium or pentamine at a dose of 0.2 mg/kg is determined. If this did not change the value of blood pressure, then the same dose is administered at the time of the onset of anesthesia and surgery; in the presence of a hypotensive reaction, the dose of the drug is halved. Then the administration of the same dose is repeated and, finally, the "residue" of the adapting dose is administered - 0.35 mg/kg. Injections are made in 5 - 7 minutes. To consolidate tachyphylaxis and enhance ganglioplegia, the gangliolytic is administered once again at a single dose at a dose of 0.75–1 mg/kg. If necessary, the drug can be re-introduced during the operation at a dose of 1–3 mg/kg. In this way, reliable ganglionic blockade is achieved while maintaining blood pressure at a normal level.

In emergency anesthesiology, there are situations when a patient develops a hypertensive crisis against the background of an acute surgical pathology. In this case, before starting the operation, it is necessary to try to reduce blood pressure to a working level. If hypertension is caused by a stressful situation, it is possible to use benzodiazepines (sibazon 5-10 mg), neuroleptics (fractional administration of droperidol 2.5-5 mg every 5-10 minutes). If it is necessary to achieve a quick effect (hypertensive crisis with the development of an attack of angina pectoris, heart failure), nitrates are used, starting with 25 mcg / min until the desired level of blood pressure is reached. It should be remembered that most often in patients with emergency surgical pathology there is a state of hypovolemia, against which a sharp decrease in blood pressure is possible, therefore, antihypertensive therapy should be combined with the elimination of hypovolemia.

For anesthesia in patients with hypertension, all known methods and drugs can be used (with the exception of ketamine). Switching off consciousness during induction anesthesia is carried out with barbiturates. In addition, anesthesia with the use of diprivan, clonidine (150 mcg 15 minutes before surgery) has proven itself well. Perhaps the use of neuroleptanalgesia. In emergency surgery, ataralgesia is often used. In any case, given the hemodynamic lability in patients with arterial hypertension, adequate infusion therapy is required in the perioperative period with a combination of crystalloid and colloid drugs. It is necessary to provide a sufficiently deep level of anesthesia before traumatic manipulations (intubation, bladder catheterization, skin incision, etc.). During anesthesia, it is desirable to maintain blood pressure at the level of working figures, however, a decrease in blood pressure by 20-25% from the original usually does not cause disturbances in cerebral blood flow and renal filtration.

Kidney function is monitored by hourly diuresis. If hypertension occurs during anesthesia, it is necessary to find its cause (insufficient analgesia, hypoxia, etc.) and take appropriate action. If there is no result, it is necessary to use antihypertensive drugs - sodium nitroprusside, nitroglycerin, phentolamine, ganglionic blockers, β-blockers (it is possible to increase the negative inotropic effect of inhalation anesthetics).

In the postoperative period, careful monitoring of blood pressure is also necessary, if possible, early extubation. If prolonged ventilation is required, sedatives are used. As the functional state of the patient is restored after surgery, one should strive for an earlier appointment of the usual therapy regimen for him. If hypertension is detected for the first time, then treatment should be prescribed taking into account the stage of hypertension.

If you have recently had surgery, your doctor may advise you to try to lower your blood pressure. You can do this by making changes to your diet and lifestyle. Be sure to check with your doctor before making any changes. He will advise you on the best options.

Steps

Dietary changes for low physical activity

    Eat less sodium. Sodium is found in salt, so limit your intake. The taste for salty food is acquired, that is, it is not inherent in a person from birth, but is formed as a habit. Some people who are accustomed to salting their food abundantly can consume up to 3.5 grams of sodium (as part of salt) daily. If you have high blood pressure after surgery and need to lower it, your doctor will recommend that you limit the amount of salt in your diet. In this case, you should consume no more than 2.3 grams of sodium daily. Do the following:

    • Be careful what you snack on. Instead of salty snacks like chips, crackers, or nuts, switch to apples, bananas, carrots, or bell peppers.
    • Choose canned foods that are low in salt or no salt at all, paying attention to the ingredients listed on the package.
    • Use much less salt when cooking, or don't add it at all. Instead of salt, use other seasonings such as cinnamon, paprika, parsley, or oregano. Remove the salt shaker from the table so as not to add salt to ready meals.

  1. Boost your health with whole grain foods. They contain more nutrients and dietary fiber than white flour and are easier to fill up. Try to get most of your calories from whole grains and other foods that contain complex carbohydrates. Eat six to eight servings a day. One serving may consist, for example, of half a glass of boiled rice or a piece of bread. Increase your intake of whole grains in the following ways:

    • Eat for breakfast oatmeal or coarse flakes. To sweeten porridge, add fresh fruits or raisins to it.
    • Study the composition of the bread you buy, giving preference to whole grains.
    • Switch from white flour to whole grain flour. The same applies to pasta.

  2. Eat more vegetables and fruits. It is recommended to eat four to five servings of fruits and vegetables per day. One serving is about half a cup. Vegetables and fruits contain micronutrients such as potassium and magnesium, which help regulate blood pressure. You can increase your intake of fruits and vegetables by:

    • Start your meal with a salad. By eating a salad first, you will muffle the feeling of hunger. Don't leave the salad for last - once you're full, you're unlikely to want to eat it. Diversify salads by adding various vegetables and fruits to them. Add as little salty nuts, cheese or sauces as possible to salads, as they contain a lot of salt. Dress up salads vegetable oil and vinegar, which contain almost no sodium.
    • For a quick snack, keep ready-to-eat fruits and vegetables on hand. When you go to work or school, bring peeled carrots, sweet pepper slices, or an apple with you.

  3. Limit your fat intake. A diet high in fat can lead to clogged arteries and high blood pressure. There are many attractive ways to reduce your fat intake while still getting all the nutrients you need to recover from surgery.

    Limit the amount of sugar you eat. Processed sugar contributes to overeating because it does not contain the nutrients your body needs to feel full. Try to eat no more than five sweets a week.

    • While artificial sweeteners like sucralose or aspartame can satisfy your sugar cravings, try replacing sweets with healthier snacks like vegetables and fruits.

    Maintaining a healthy lifestyle after surgery

    1. Quit smoking . Smoking and/or chewing tobacco constricts blood vessels and reduces their elasticity, leading to an increase in blood pressure. If you live with a smoker, ask him not to smoke in your presence so that you do not breathe tobacco smoke. This is especially important during the recovery period after surgery. If you smoke yourself, try to stop this bad habit. To do this, you can do the following:

    2. Don't drink alcohol. If you've recently had surgery, you're most likely taking medication to help you recover faster. Alcohol interacts with many medications.

      • In addition, your doctor may advise you to lose weight as well. alcoholic drinks contain a large number of calories, which will make your task more difficult.
      • If you find it difficult to stop drinking alcohol, talk to your doctor, who can prescribe the appropriate treatment for you and recommend where you can go for support.

    3. Try to reduce stress. Recovery after surgery is not easy, both physically and psychologically. Try these popular relaxation techniques that you can practice even with limited mobility:

      • Music or art therapy;
      • visualization (presentation of soothing pictures);
      • progressive tension and relaxation of individual muscle groups.

    4. If your doctor allows, exercise. This is a great way to reduce stress and get rid of excess weight. However, in the process of recovery after surgery, it is important to observe the measure and not overload your body.

      • Walking every day is completely safe after many types of surgeries, so check with your doctor to see if they are appropriate for you and when you can start.
      • Talk to your doctor and physical therapist about a safe exercise program. Continue to see your doctor and physical therapist regularly so they can monitor your condition and see if you are still physical exercise are good for you.

    Consultations with a doctor

    1. If you think you have high blood pressure, call your doctor. In most cases, people do not realize that they have high pressure because often it is not accompanied by noticeable symptoms. However, the following signs may indicate high blood pressure:

      • labored breathing;
      • headache;
      • nosebleeds;
      • blurred or double vision.

    2. Take blood pressure medication prescribed by your doctor. While you are recovering from surgery, your doctor may prescribe medications to lower your blood pressure. Because they can interact with other medicines, tell your doctor about all medicines you take, including over-the-counter medicines, supplements, and herbal remedies. Your doctor may prescribe the following drugs for you:

      • ACE inhibitors. These drugs cause the blood vessels to relax. They often interact with other medications, so tell your doctor about all medications you are taking.
      • calcium antagonists. This type of drug dilates the arteries and lowers the heart rate. Do not drink grapefruit juice while taking them.
      • Diuretics. These drugs increase the frequency of urination, thereby lowering the salt content in the body.
      • Beta blockers. Drugs of this type reduce the frequency and strength of the heartbeat.

In a healthy person, after anesthesia, there is a decrease in blood pressure and short-term bradycardia. This is due to the peculiarity of the effect of drugs for anesthesia on the body. Increased blood pressure after anesthesia can be observed in hypertensive patients due to a decrease in vascular elasticity. In most cases, this is a short-term phenomenon, but with a significant increase in blood pressure, appropriate measures must be taken.

Normally, blood pressure after general anesthesia is always low. This is due to the principle of action of drugs used for pain relief. They inhibit the activity of the nervous system, as a result, all processes in the body slow down. Since the nervous system needs time to recover, on the first day after general anesthesia, a breakdown and dizziness are possible, due to a decrease in pressure by 15-20 mm Hg. compared to normal human levels.

High blood pressure after anesthesia is a problem for hypertensive patients. This is due to the following mechanisms occurring in the body.

The prolonged course of hypertension leads to a violation of the elasticity of blood vessels. They lose flexibility and can no longer quickly respond to changing internal and external conditions. Due to the loss of elasticity, the change in vascular tone occurs slowly and usually it is always increased, which is explained by the peculiarities of the cardiovascular system.

In hypertensive patients, vascular elasticity is insufficient for an adequate response

At the time of the introduction of anesthesia, all processes in the body slow down. The absence of pain syndrome is explained by the effect on the nervous system, which inhibits the work of certain receptors. At this time, for every person, including hypertensive patients, all processes in the body slow down, including pressure, heartbeat and breathing.

After the anesthesia ceases to act, the vascular tone rapidly increases, that is, it returns to a normal state characteristic of hypertension. Due to the prolonged decrease in vascular tone at the time of anesthesia, too rigid walls experience even more stress, so the pressure rises. For example, if before the operation, a hypertensive patient always had a pressure of 150 mm Hg, after the cessation of anesthesia, it can jump to 170. This state persists for some time, and then the pressure returns to normal.

What is the danger of increasing blood pressure during surgery?

In rare cases, with hypertension, the pressure remains high even despite the effect of anesthesia. This phenomenon is dangerous and requires monitoring of the patient's condition during the operation.

Increased pressure during the action of local anesthesia or general anesthesia can cause large blood loss, due to high vascular tone.

There are a number of risks when administering potent anesthesia to hypertensive patients. These include:

  • hemorrhages in the brain during the operation;
  • cardiac arrhythmia in response to anesthesia;
  • heart failure;
  • hypertensive crisis after the cessation of anesthesia.

Adequate therapy of hypertension before surgery helps to prevent dangerous complications. Usually, the operating doctor, knowing about the patient's high blood pressure, makes a number of recommendations some time before the operation. This makes it possible to minimize Negative consequences anesthesia.


High blood pressure during surgery can cause bleeding

Hypotension and anesthesia

If in hypertension the danger lies in the fact that the pressure remains high both during the action of anesthesia and after surgery, then in hypotension the risks are due to a sudden drop in blood pressure.

After anesthesia, low pressure drops even lower, especially when general anesthesia is administered. During the operation, the vital signs of patients are carefully monitored, as there is a risk of pressure drop to critical values.

During the operation, negative reactions of the body to the effect of anesthesia may occur. For hypotensive patients, this is dangerous with acute hypoxia of the brain and sudden cardiac arrest.

Help for hypertensive patients after anesthesia

Having figured out that the pressure can really increase after anesthesia, you should first consult with the anesthesiologist and the operating doctor about methods for reducing pressure after the cessation of anesthesia.

Usually, hypertensive patients are given an injection of magnesia to reduce in the hospital. The clinic staff carefully monitors fluctuations in the patient's blood pressure both at the time of the operation and after the cessation of anesthesia.

If magnesia is ineffective, more potent drugs can be used. In addition to drugs, a patient prone to high blood pressure is shown bed rest, regardless of the type of operation, and rest. To speed up recovery after anesthesia, a balanced diet is necessary.

Before the operation, a hypertensive patient must inform the doctor about all allergic reactions to drugs. It is imperative to inform the doctor about the antihypertensive drugs that the patient takes constantly.

Despite the discomfort during the pressure surge, the patient has nothing to worry about, since the normalization of blood pressure after the operation is carried out by qualified specialists.

Means for anesthesia slightly reduce pressure, slow down the pulse and respiratory rate. But this is provided that under anesthesia the pressure indicators were within the normal range. Low or high blood pressure combined with anesthesia can lead to serious complications, so specialists strive to regulate all indicators before surgery.

General information

General anesthesia is a temporary inhibition of the functions of the central nervous system, which is accompanied by a loss of consciousness, inhibition of sensitivity, muscle relaxation, inhibition of reflexes and analgesia for surgical intervention. General anesthesia is carried out by suppressing the synaptic connection between neurons. There are 4 consecutive stages of general anesthesia, each of which is characterized by different indicators:

Enter your pressure

Move the sliders

  • BP, arterial pressure;
  • HR, heart rate;
  • RH is the frequency of respiration.

How does anesthesia affect blood pressure?

The effect on normal blood pressure is presented in the form of a table:

Reaction when high blood pressure

  • There may be a lot of blood loss during the operation.
  • Hemorrhage in the brain.
  • Hypersensitivity of the heart and blood vessels to surgery and drugs.
  • development of severe heart failure.

Under reduced pressure

  • Possible hypovolemic shock.
  • Heart failure.

Why is anesthesia dangerous?


An overdose can be fatal.

In case of an overdose, if the anesthetics have touched the respiratory and vascular-motor centers of the medulla oblongata, the agonal stage begins. Breathing stops and death occurs. In addition to overdose, other complications arise:

  • Hypoxic syndrome, which may be due to airway obstruction with vomit, laryngospasm and bronchospasm.
  • Hypertensive crisis, hemorrhagic stroke, if hypertension has not been eliminated before surgery. A hypotensive crisis may occur due to blood loss or if anesthesia is administered under reduced pressure. Rarely, there may be myocardial infarction, pulmonary edema and thrombosis of the pulmonary circulation.
  • Anaphylactic shock. Functional adrenal insufficiency.
  • After anesthesia, there may be jumps in blood pressure.

A. Bogdanov, FRCA

Hypertension is a very common disease. For example, in the United States, according to some estimates, up to 15% of the adult population suffers from hypertension. This is neither more nor less than 35 million people! Naturally, the anesthesiologist encounters such patients almost every day.

The severity of the disease increases with age. However, recent studies have shown that a significant proportion of children, at least in the United States where the study was conducted, have a tendency to high blood pressure. According to many hypertension experts, this condition develops into hypertensive disease later in life, although blood pressure in such patients remains normal until 30 years of age.

Physiological changes in patients in initial stage hypertension is minimal. Sometimes they have increased cardiac output, but peripheral vascular resistance remains normal. Sometimes there is an increase in diastolic pressure up to 95 - 100 mm Hg. In this phase of the disease, no disturbances are detected on the part of the internal organs, the defeat of which manifests itself in a later stage (brain, heart, kidneys). The average duration of this phase is 5 - 10 years, until the phase of constant diastolic hypertension occurs with diastolic pressure constantly exceeding 100 mm Hg. At the same time, previously elevated cardiac output is reduced to normal. There is also an increase in peripheral vascular resistance. Clinical symptoms in this phase of the disease vary widely and most often include headache, dizziness, and nocturia. This phase lasts quite a long time - up to 10 years. The use of drug therapy in this phase leads to a pronounced decrease in mortality. And this means that the anesthesiologist will meet with patients receiving sufficiently strong antihypertensive drugs in the relative absence of severe clinical symptoms.

After some time, an increase in peripheral vascular resistance and a decrease in organ blood flow cause disturbances in the internal organs, most often manifested as:

  1. Hypertrophy of the left ventricle with an increase in its blood supply; this creates conditions for the development of coronary artery disease and heart failure.
  2. Renal failure due to progressive atherosclerosis of the renal arteries.
  3. Impaired brain function as a result of both transient ischemic episodes and small strokes.

In the absence of treatment in this phase of the disease, the predicted life expectancy is 2 to 5 years. The entire process described can take a much shorter time - several years, sometimes months, when the disease is especially malignant.

The stages of hypertension are summarized in the table.

Table 1 . Stages of hypertension.

Comments and clinical manifestations

Anesthetic risk

Labile diastolic hypertension (diastolic blood pressure< 95)

Elevated CO, normal PSS, No dysfunction of internal organs. Virtually no symptoms. Diastolic blood pressure is sometimes elevated, more often normal.

< 110 и нет нарушений со стороны внутренних органов

Persistent diastolic hypertension

CO decreases, PSS rises. At first there are no symptoms, but later - dizziness, headache, nocturia. ECG shows LV hypertrophy

No more than in a healthy person, provided that diastolic blood pressure< 110 и нет нарушений со стороны внутренних органов

Internal disorders

Heart - LV hypertrophy, heart failure, myocardial infarction. CNS - strokes, cerebrovascular accidents. Kidneys - insufficiency.

High if not thoroughly evaluated and treated.

Organ failure

Serious failure of the above organs

Very tall

Until recently, systolic hypertension with normal diastolic pressure was considered a natural consequence of aging. However, at present a number of authors express their doubts about this; however, this form of hypertension is generally considered to be a risk factor.

The search for biochemical causes of hypertension has not yet been successful. There is no evidence of sympathetic nervous system hyperactivity in these patients; moreover, it seems that its activity is suppressed. In addition, evidence is accumulating that, contrary to popular belief, there is no retention and accumulation of sodium in the body, with the exception of certain conditions accompanied by activation of the renin-angiotensin system. Clinical studies confirm the fact that hypertensive patients excrete excess sodium in the same way as healthy people. Although dietary sodium restriction may improve the patient's condition, there is no evidence of pathological sodium retention in such patients.

An actual decrease in BCC was noted in patients with hypertension who did not receive treatment. This fact may explain the increased sensitivity of such patients to the hypotensive effect of volatile anesthetics.

According to modern views hypertension is a quantitative rather than a qualitative deviation from the norm. The degree of damage to the cardiovascular system depends on the degree of increase in blood pressure and the duration of this condition. Therefore, from a therapeutic point of view, a drug-induced decrease in blood pressure is accompanied by an increase in the life expectancy of these patients.

Preoperative assessment of the condition of patients with hypertension

From a practical point of view, one of the most difficult problems for an anesthesiologist faced with a patient with hypertension is the differential diagnosis between primary hypertension (hypertension) and secondary. If there is enough evidence in favor of hypertension, then the question is reduced to an adequate assessment of the patient's condition and determining the degree of operational risk.

The cardiovascular system

The leading cause of death in an untreated hypertensive patient is heart failure (see table).

Table 2. Causes of mortality in patients with hypertension (in descending order)

Untreated hypertension

  • * Heart failure
  • * Stroke
  • * Kidney failure

Treated hypertension

  • * Myocardial infarction
  • * Kidney failure
  • *other reasons

The simplified mechanism of events in this case is approximately the following: increased peripheral vascular resistance leads to left ventricular hypertrophy and an increase in its mass. Such hypertrophy is not accompanied by an adequate increase in coronary blood flow, which leads to the development of relative myocardial ischemia. Ischemia in combination with increased peripheral vascular resistance creates conditions for the development of left ventricular failure. The diagnosis of left ventricular failure can be established on the basis of such signs as the presence of moist rales in the basal parts of the lungs, left ventricular hypertrophy and darkening in the lungs on the radiograph, signs of left ventricular hypertrophy and ischemia on the ECG. However, it should be noted that in such patients, left ventricular hypertrophy is diagnosed using echocardiography; ECG and chest x-ray often do not change. In these cases, the patient should be carefully questioned for coronary disease hearts. If a major operation is to be undertaken, then it is quite possible that a more detailed assessment of the coronary circulation system is necessary. Naturally, the presence of even a small degree of left ventricular failure seriously increases the degree of operational risk; it needs to be corrected before the operation.

The patient's complaints provide additional information. Decreased exercise tolerance is a useful indicator of the patient's response to the upcoming surgical stress. Episodes of shortness of breath at night and nocturia in history should make the anesthesiologist think about the state of the reserves of the patient's cardiovascular and urinary systems.

Evaluation of the degree of change in the fundus provides an excellent opportunity to establish the severity and duration of hypertension. This is especially important in patients with previously undiagnosed hypertension. The most commonly used classification is Keith-Wagner, which includes 4 groups:

Although arteriosclerosis and hypertension are different diseases, there is no doubt that atherosclerotic changes develop faster in hypertensive patients. This affects the coronary, renal, cerebral vessels, reducing the perfusion of the relevant organs.

urinary system

A characteristic manifestation of hypertension is sclerosis of the renal arteries; this leads to a decrease in renal perfusion and, initially, to a decrease in glomerular filtration rate. With the progression of the disease and further deterioration of renal function, creatinine clearance decreases. Therefore, the definition of this indicator is an important marker of impaired renal function in hypertension. The proteinuria developing in addition to it is diagnosed at the general analysis of urine. Untreated hypertension leads to renal failure with azotemia and hyperkalemia. It should also be borne in mind that with prolonged use of diuretics for the treatment of hypertension in such patients (especially the elderly), hypokalemia develops. Therefore, the determination of plasma potassium levels should be included in the routine preoperative examination of hypertensive patients.

Late stages of renal failure lead to fluid retention as a result of a combination of increased renin secretion and heart failure.

Central nervous system

The second most common cause of death in patients with untreated hypertension is stroke. In the later stages of the disease, arteriolitis and microangiopathy develop in the vessels of the brain. The resulting small aneurysms at the level of arterioles are prone to rupture with an increase in diastolic pressure, causing a hemorrhagic stroke. In addition, high systolic pressure leads to an increase in cerebral vascular resistance, which may be the cause of ischemic stroke. In severe cases, acute hypertension leads to the development of hypertensive encephalopathy, which requires an emergency lowering of blood pressure.

Drug therapy for hypertension

In addition to knowledge of the pathophysiology of hypertension and a clear understanding of the physiological status of the patient, the anesthesiologist needs knowledge of the pharmacology of antihypertensive drugs, in particular their possible interactions with drugs used during anesthesia. These drugs, as a rule, have a fairly long-term effect, that is, they continue to exert their influence during anesthesia, and often after its termination. Many antihypertensive drugs affect the sympathetic nervous system, so it makes sense to briefly review the pharmacology and physiology of the autonomic nervous system.

The sympathetic nervous system is the first of two components of the autonomic nervous system. The second part is represented by the parasympathetic nervous system. Postganglionic fibers of the sympathetic nervous system are called adrenergic and perform a number of functions. The neurotransmitter in these fibers is norepinephrine, which is stored in vesicles located along the entire floor of the adrenergic nerve. Sympathetic nerve fibers do not have structures similar to the neuromuscular synapse; nerve endings form something like a network that envelops the innervated structure. Upon stimulation of the nerve ending, vesicles with norepinephrine are ejected from the nerve fiber into the interstitial fluid by reverse pinocytosis. Receptors located close enough to the site of norepinephrine release are stimulated under its influence and cause an appropriate response from effector cells.

Adrenergic receptors are divided into α1 α2, α3, β1 and β2 receptors.

1-receptors are classic postsynaptic receptors, which are a receptor-activated calcium channel, the activation of which is accompanied by an increase in the intracellular synthesis of phosphoinositol. This in turn leads to the release of calcium from the sarcoplasmic reticulum with the development of a cellular response. α1 receptors mainly cause vasoconstriction. Norepinephrine and epinephrine are non-selective ?-receptor agonists, that is, they stimulate both? 1 and? 2-subgroups. Prazosin, which is used as an oral antihypertensive drug, belongs to ?1-receptor antagonists. Phentolamine also causes mostly? I-blockade, although to a lesser extent it blocks and? 2-receptors.

a2 receptors are presynaptic receptors, the stimulation of which reduces the rate of activation of adenylate cyclase. Under the influence of a2 receptors, the further release of norepinephrine from the endings of adrenergic nerves is inhibited according to the principle of negative feedback.

Clonidine refers to non-selective α-receptor agonists (ratio α2-effect: α1-effect = 200: 1); this group also includes dexmedothymidine, which has a much greater selectivity.

1 receptors are generally defined as cardiac receptors. Although their stimulation occurs under the influence of adrenaline and noradrenaline, isoproterenol is considered the classic agonist of these receptors, and metoprolol is the classic antagonist. The α3I receptor is the enzyme adenylcyclase. Upon stimulation of the receptor, an increase in the intracellular concentration of cyclic AMP occurs, which in turn activates the cell.

The 3 and 2 receptors are considered to be mainly peripheral, although their presence has recently been found in cardiac muscle. Most of them are presented in the bronchi and smooth muscles of peripheral vessels. The classical agonist of these receptors is called terbutaline, the antagonist is atenolol.

Preparations for the treatment of hypertension

1-agonists: prazosin is the only member of this group used for long-term treatment of hypertension. This drug reduces peripheral vascular resistance without significantly affecting cardiac output. Its advantage is the absence of serious side effects from the central nervous system. Total side effects is small, no interactions with drugs used on the day of anesthesia have been described.

Phenoxybenzamine and phentolamine (Regitin) are ?1-blockers most commonly used to correct hypertension in pheochromocytoma. They are rarely used in the routine treatment of hypertension. However, phentolamine can be used for emergency correction of blood pressure in hypertensive crisis.

a2-agonists: a few years ago, a representative of this group of drugs, cponidine, was widely used to treat hypertension, but its popularity has noticeably decreased due to severe side effects. Clonidine stimulates a2 receptors in the central nervous system, which ultimately reduces the activity of the sympathetic nervous system. A well-known problem associated with clonidine is the withdrawal syndrome, which is clinically manifested in the development of severe hypertension 16 to 24 hours after discontinuation of the drug. Therapy with clonidine is a rather serious problem for the anesthetist in connection with the withdrawal syndrome. If the patient is to have a relatively minor operation, then the usual dose of clonidine is taken a few hours before induction of anesthesia. After recovery from anesthesia, it is recommended to start oral administration of the drug in usual doses as soon as possible. However, if the patient is to undergo an operation that will prevent him from taking oral medications for quite a long time, it is recommended that the patient be switched to another antihypertensive drug before elective surgery, which can be done gradually over a week using oral medications, or somewhat faster with them. parenteral administration. In the case of urgent surgery, when there is no time for such manipulations, in the postoperative period, it is necessary to monitor such patients in the intensive care unit with careful monitoring of blood pressure.

ß-blockers: the table below shows the drugs of this group, the most commonly used for the treatment of hypertension.

Drug b1-receptor

main path

selectivity

half-life (hour)

breeding

propranolol

metoprolol

Atenolol

Propranolol: the first β-blocker used in the clinic. It is a racemic mixture, while the L-form has a greater β-blocking activity, and the D-form has a membrane stabilizing effect. A significant amount of propranolol, when taken orally, is immediately eliminated by the liver. The main metabolite is 4-hydroxy propranolol, an active β-blocker. The half-life of the drug is relatively short - 4-6 hours, but the duration of the blockade of receptors is longer. The duration of action of propranolol does not change with impaired renal function, but can be shortened under the influence of enzyme inducers (phenobarbital). The spectrum of antihypertensive action of propranolol is characteristic of all β-blockers. It includes a decrease in cardiac output, renin secretion, sympathetic influence of the central nervous system, as well as blockade of reflex stimulation of the heart. The side effects of propranolol are quite numerous. Its negative inotropic effect can be enhanced by a similar effect of volatile anesthetics. Its use (like most other β-blockers) is contraindicated in bronchial asthma and chronic obstructive pulmonary diseases, since airway resistance increases under the influence of β-blockade. It should also be borne in mind that propranolol potentiates the hypoglycemic effect of insulin in diabetics. A similar effect is inherent in all β-blockers, but is most pronounced in propranolol.

Nadolol (korgard), like propranolol, is a non-selective blocker of β1 and β2 receptors. Its advantages include much more long time half-life, which allows you to take the drug once a day. Nadolol does not have a quinidine-like effect, and therefore its negative inotropic effect is less pronounced. In terms of lung disease, nadolol is similar to propranolol.

Metoprolol (lopressor) blocks predominantly β1-receptors, and therefore is the drug of choice for lung diseases. It has been clinically noted that its effect on airway resistance is minimal compared to propranolol. The half-life of metoprolol is relatively short. There are isolated reports of a pronounced synergism of the negative inotropic action of metoprolol and volatile anesthetics. Although these cases are considered rather as casuistry, and not a pattern, anesthesia of patients using this drug should be approached with extreme caution.

Labetalol is a relatively new drug with AI, βI, β2-blocking activity. It is often used in anesthesiology not only for hypertensive crises, but also to create controlled hypotension. The half-life of labetalol is about 5 hours, it is actively metabolized by the liver. The ratio of β u α blocking activity is approximately 60:40. This combination allows you to lower blood pressure without the occurrence of reflex tachycardia.

Timolol (blockadren) is a non-selective β-blocker with an elimination half-life of 4 to 5 hours. Its activity is approximately 5 to 10 times more pronounced than that of propranolol. The drug is used mainly locally in the treatment of glaucoma, however, due to the pronounced effect, systemic β-blockade is often observed, which should be taken into account when anaesthetizing patients with glaucoma.

Drugs of other groups are also used to treat hypertension. Probably, one of the longest used drugs is Aldomet (a-methyldopa), the duration of which has been used in the clinic for more than 20 years. It was assumed that this drug realizes its action as a false neurotransmitter. More recent studies have found that methyldopa is converted in the body to a-methylnorepinephrine, which is a potent a2-agonist. Thus, in terms of mechanism of action, it resembles clonidine. Under the influence of the drug, a decrease in peripheral vascular resistance is observed without a noticeable change in cardiac output, heart rate or renal blood flow. However, Aldomet has a number of side effects that are important for the anesthesiologist. First of all, there is a potentiation of the action of volatile anesthetics with a decrease in their MAC. This is understandable, given the similarity of the action of clonidine and aldomet. Another problem is the fact that long-term therapy with aldomet in 10-20% of patients causes the appearance of a positive Coombs test. In rare cases, hemolysis has been described. Difficulties with determination of compatibility at blood transfusion are noted. In 4-5% of patients under the influence of aldomet, an abnormal increase in hepatic enzymes is noted, which should be taken into account when using halogen-containing volatile anesthetics (hepatotoxicity). It should be emphasized that no relationship has been reported between the hepatotoxicity of volatile anesthetics and aldomet. In this case, we are talking more about issues of differential diagnosis.

Diuretics: Thiazide diuretics are the most commonly used of this group of drugs. Their side effects are well known and should be taken into account by the anesthetist. The main problem in this case is hypokalemia. Although hypokalemia per se can cause ventricular arrhythmias up to and including fibrillation, it is now believed that chronic hypokalemia resulting from long-term use of diuretics is not as dangerous as previously thought.

A decrease in circulating blood volume under the influence of diuretics has also been described, especially in the early stages of therapy. The use of various anesthetics in this situation may be accompanied by the development of rather severe hypotension.

Angiotensin-converting enzyme inhibitors: These include captopril, lisinopril, enalapril. These drugs block the conversion of inactive angiotensin 1 to active angiotensin 11. Therefore, these drugs are most effective in renal and malignant hypertension. Of the side effects, one should keep in mind a slight increase in the level of potassium. No serious interactions between captopril and drugs for anesthesia have been described. However, some cardiac centers avoid preoperative use of these drugs because severe and refractory hypotension has been described. It should also be taken into account that drugs of this group can cause a massive release of catecholamines in pheochromocytoma.

Calcium channel blockers: The most popular member of this group is nifedipine, which not only causes vasodilation but also blocks renin secretion. Sometimes this drug can cause quite significant tachycardia. Theoretically, drugs in this group can interact with volatile anesthetics, causing hypotension; however, this concept has not been clinically validated. However, the combination of calcium channel blockers and β-blockers should be kept in mind in the context of the use of volatile anesthetics. This combination can seriously reduce myocardial contractility.

Anesthesiological approach to a patient with hypertension

Times change. 20 years ago general rule all antihypertensive drugs were discontinued at least 2 weeks prior to elective surgery. Now it's the other way around. It is axiomatic that the hypertensive patient is maximally prepared for the operation, whose arterial pressure is controlled with the help of drug therapy up to the moment of the operation. Moreover, there is some evidence that operative risk is increased in untreated hypertensive patients.

A number of large epidemiological studies have shown that at a diastolic pressure level below 110 mm Hg. and in the absence of serious subjective complaints, elective surgery does not represent an increased risk for such patients. Naturally, this does not apply to cases where there are organ disorders as a result of hypertension. From a practical point of view, this means that an asymptomatic patient with labile hypertension, or with constantly elevated blood pressure, but with a diastolic pressure below 110 mm Hg. in the case of a planned operation has no greater operational risk than a patient with normal blood pressure. However, the anesthesiologist should keep in mind that such patients have very labile blood pressure. During surgery, they often develop hypotension, and in the postoperative period, hypertension in response to the release of catecholamines. Naturally, it is desirable to avoid both extremes.

Currently, hypertension is not a contraindication for any type of anesthesia (excluding the use of ketamine). It is important to note that it is necessary to achieve a sufficiently deep level of anesthesia before stimulation that causes activation of the sympathetic nervous system, such as tracheal intubation. The use of opiates, local anesthetics for irrigating the trachea also, according to some authors, can reduce sympathetic stimulation.

What level of blood pressure is optimal during surgery in a patient with hypertension? It is difficult, if not impossible, to answer this question definitively. Of course, if the patient has a moderately elevated diastolic pressure, then some decrease in it is likely to improve myocardial oxygenation. Reducing the increased tone of the peripheral vessels (afterload) ultimately leads to the same result. Therefore, a moderate decrease in blood pressure, especially if it is initially elevated, is quite reasonable. Fluctuations in blood pressure most dramatically affect changes in renal blood flow. Naturally, assessing glomerular filtration during surgery is quite difficult. The best practical monitor in this case is the assessment of hourly diuresis.

It is known that autoregulation of cerebral blood flow does not disappear in hypertensive disease, but the autoregulation curve shifts to the right towards higher numbers. Most hypertensive patients tolerate a drop in blood pressure of 20-25% of the original without any disturbance of cerebral blood flow. In such situations, the anesthesiologist is faced with a dilemma: lowering blood pressure, on the one hand, reduces mortality from heart failure, and on the other hand, increases the number of problems associated with a decrease in brain perfusion. One way or another, a moderate decrease in blood pressure is better from a physiological point of view than its increase. The anesthesiologist should remember that the use of β-blockers in hypertensive patients during anesthesia enhances the negative inotropic effect of volatile anesthetics, and therefore they should be used with great care. Bradycardia with the use of j3-blockers is corrected by intravenous atropine or glycopyrrolate. If this is not enough, intravenous calcium chloride can be used: adrenomimetics are the last line of defense.

As mentioned above, discontinuation of antihypertensive therapy before surgery is rare in modern practice. It has been convincingly proven. that continued use of almost all antihypertensive drugs not only reduces the hypertensive response to tracheal intubation, but also increases the stability of blood pressure in the postoperative period.

Patients with severe hypertension, which is defined as diastolic blood pressure greater than 110 mm Hg. and/or signs of multiple organ failure are a slightly more complex problem. If hypertension is diagnosed for the first time in such patients and they have not received any treatment, then elective surgery should be postponed and medical treatment should be prescribed (or revised) until blood pressure falls to acceptable levels. In surgical patients, severe hypertension is accompanied by increased operative mortality. From this point of view, relative contraindications to a planned operation are:

  1. Diastolic pressure above 110 mm Hg.
  2. Severe retinopathy with exudate, hemorrhage and papilledema.
  3. Renal dysfunction (proteinuria, decreased creatinine clearance).

Postoperative period

In the operating room, the anesthesiologist is in an ideal position, when constant monitoring allows you to quickly diagnose certain disorders and take measures to correct them. Naturally, pain impulses that cause sympathetic stimulation are much easier to suppress in the operating room than anywhere else. After the cessation of anesthesia, pain impulses and all other stimuli can cause a significant increase in blood pressure. Therefore, monitoring of arterial pressure in the immediate postoperative period has importance. Patients with very labile blood pressure may require invasive monitoring.

One of the advantages of the recovery room is that the patient is already out of anesthesia and can be contacted. The very fact of establishing contact serves as a diagnostic technique, indicating the adequacy of brain perfusion. In this case, blood pressure can be reduced to the required level and at the same time be able to assess the adequacy of cerebral blood flow.

It should also be noted that, according to a number of authors, lowering blood pressure in hypertensive patients is contraindicated if there is a history of stroke or cerebrovascular accident. In this case, the autoregulation of the cerebral blood flow disappears and lowering blood pressure becomes risky. This issue is still being debated and there is no consensus on this matter.

Monitoring of the ST segment and kidney function (diuresis) remains important.

It must also be borne in mind that in addition to hypertension, there are a number of other reasons for high blood pressure. For example, hypercapnia and an overfilled bladder are just two of the factors that can lead to severe hypertension. It is hardly advisable to use antihypertensive therapy without first eliminating the cause of hypertension.

Literature

    B. R. Brown "Anaesthesia for the patient with essential hypertension" Seminars in Anesthesia, vol 6, No 2, June 1987, pp 79-92

    E.D. Miller Jr "Anesthesia and Hypertension" Seminars in Anesthesia, vol 9, No 4, December 1990, pp 253 - 257

    Tokarcik-I; Tokarcikova-A Vnitr-Lek. Feb 1990; 36(2): 186-93

    Howell SJ; Hemming-AE; Allman KG; Glover L; Sear-JW; Foex-P "Predictors of postoperative myocardial ischaemia. The role of intercurrent arterial hypertension and other cardiovascular risk factors". Anaesthesia. Feb 1997; 52(2): 107-11

    Howell SJ; Sea-YM; Yeates-D; Goldacre M; Sear-JW; Foex-P "Hypertension, admission blood pressure and perioperative cardiovascular risk." Anaesthesia. Nov 1996; 51(11): 1000-4

    Larsen-JK; Nielsen-MB; Jespersen-TW Ugeskr-Laeger. 1996 Oct 21; 158(43): 6081-4

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