Perioperative hypertension: when the blood pressure increases by more than 20% of the basic value or above 140/90mmHg

reason

Perioperative hypotension: the drop in systolic blood pressure exceeds 20% of the basic value or falls below 80mmHg

reason

Conducive to surgical operations

Reduce blood loss, blood transfusion and blood waste

Increase safety during surgery

Main factors for maintaining blood pressure: cardiac output CO, systemic vascular resistance TSVR, circulating blood volume, blood vessel wall elasticity and blood viscosity

Mean arterial pressure MAP = CO × TSVR. The purpose of lowering blood pressure can be achieved by reducing TSVR while keeping cardiac output unchanged.

The "safe" lower limit of MAP for controlled hypotension is 50-60mmHg

Whether the blood in tissues and organs decreases is critical

Stable cardiac output is important to maintain tissue blood perfusion

Sufficient effective circulating volume is necessary to maintain adequate blood perfusion of organs.

The greatest danger lies in hypoxic damage to the brain and myocardium

In patients with chronic hypertension, the lower limit of safety and the lower limit of cerebral blood flow CBF are elevated. After effective antihypertensive treatment is applied, the CBF autoregulation curve can return to the normal position.

Patients with suspected ischemic heart disease should not undergo controlled hypotension in principle

For those with normal blood pressure before surgery, control systolic blood pressure to no less than 10.7kPa (80mmHg), or MAP between 50-60mmHg

The standard is to reduce the basal blood pressure by 30%, and make appropriate adjustments according to the blood leakage in the surgical field and the patient's condition.

Blood pressure reduction is mainly performed when there is the most bleeding or during the most important steps of the surgery, and the time for blood pressure reduction should be shortened as much as possible.

When MAP drops to 50mmHg, the time for each blood pressure reduction should not exceed 30 minutes.

If the operation time is long, if the blood pressure is only reduced by 30% of the basic value, the time for each blood pressure reduction should not exceed 1.5 hours.

Surgery where heavy bleeding and difficult hemostasis are expected, such as giant meningioma and pelvic surgery

Vascular surgery, such as aortic aneurysm, patent ductus arteriosus, intracranial vascular malformation

Fibrous surgery, delicate surgery in a small area that requires a clear surgical field, such as middle ear surgery and endoscopic sinus surgery

Those who have difficulty transfusing large amounts of blood or have contraindications to blood transfusion, or those who refuse blood transfusion due to religious beliefs

Those whose blood pressure, intracranial pressure and intraocular pressure rise excessively during anesthesia, which may lead to serious adverse consequences

Those with substantial lesions in important organs, such as cerebrovascular disease (severe hypertension, cerebral infarction), cardiac insufficiency (severe coronary heart disease, heart failure), severe liver and kidney insufficiency

Patients with vascular disease, such as severe hypertension, arteriosclerosis and organ malperfusion

hypovolemia or severe anemia

In patients with increased intracranial pressure, lowering blood pressure before surgical craniotomy is contraindicated.

For patients with obvious reduced oxygen transport in the body, organs, and tissues, the pros and cons of intraoperative controlled hypotension should be carefully weighed before using it as appropriate.

1. Cerebral embolism and cerebral hypoxia 2. Insufficient coronary blood supply, myocardial infarction, heart failure or even cardiac arrest 3. Renal insufficiency 4. Vascular embolism 5. Reactive bleeding after lowering blood pressure and bleeding at the surgical site 6. Sustained hypotension and shock 7. Drowsiness, prolonged awakening, etc.

1. Inhalation anesthetics and intravenous anesthetics 2. Vascular (direct) dilators (sodium nitroprusside, nitroglycerin) 3. Calcium channel blockers 4. Adrenaline α1 and β receptor blockers (phentolamine, esmolol) 5. Sympathetic ganglion blocking drugs 6. Potassium channel opener drugs 7. Angiotensin-converting enzyme inhibitors 8. Prostaglandin E1, etc. 1. Inhalation anesthetics, intravenous anesthetics

inhalation anesthetic

vasodilators

calcium channel blockers

Adrenaline 1,  receptor blocking drugs

adrenergic  receptor blockers

Adrenaline 1,  receptor blocking drugs

anesthesia requirements

blood loss

Voltage reduction range

ventilation and oxygenation

surgical position

monitor

stop bucking

Postoperative care