Postoperative Circulation Management (Anesthesia Handout)

Key content

Postoperative myocardial ischemia is predisposed to

1.
Oxygen transport

Maintaining oxygen transport to meet the needs of tissue metabolism is the purpose of postoperative circulation regulation

Three major factors affecting oxygen transport

Adjustment of cardiac output requires control of heart rate and rhythm, maintenance of acceptable preload, adjustment of afterload, maintenance of ventricular muscle contractility to manage hypocardiac syndrome; Provides both an acceptable hemoglobin concentration and an appropriate oxygen saturation

The data show that maintaining hematocrit between 30%~33% can maintain oxygen-carrying capacity and blood viscosity in the best balance

Hypoxemia of any cause can reduce oxygen supply

When airway resistance increases, treatment of bronchospasm increases arterial partial pressure of oxygen and cardiac output
.

When compliance decreases, the use of end-expiratory positive pressure and continuous positive pressure ventilation facilitates re-expansion
of the atelectasis lung.

Second, the evaluation of the cycle of physical examination

Invasive tests – pulmonary arterial catheters (PACs)

Echocardiography

Decreased myocardial contractility

Drugs that increase vasoconstriction increase the mobilization of calcium ions derived from intracellular and contractile proteins, or increase
the sensitivity of these proteins to calcium.

Drugs for the treatment of perioperative cardiac insufficiency, drug-denatured drugs

Left Simondan

Combination therapy: catecholamines

Phosphodiesterase inhibitors

Vasodilators for pulmonary vasodilators

3.
Postoperative arrhythmia

Later after surgery (1~3 days after surgery), supraventricular arrhythmias became the main problem, mainly atrial fibrillation
.
The incidence of postoperative atrial fibrillation is 30%~40%, but with the increase of age and valve surgery, the incidence can exceed 60%.

Causes of occurrence:

Genetic factors

Inappropriate myocardial protection during surgical procedures

Electrolyte abnormalities

Fluid replacement causes changes in atrial volume

Epicarditis

Stress and irritation

Risk factors:

Older age

History of atrial fibrillation

Valve surgery is performed

Prevention of atrial fibrillation

treat

4.
Postoperative hypothermia (1) Reduce the core temperature through cardiopulmonary diversion

(2) Increase the core temperature by cardiopulmonary diversion

(3) The body temperature drops again after weaning

(4) Rewarming after entering the ICU

After surgery, patients are often admitted to the ICU when the central body temperature is below 35°C,

Especially heart surgery
without cardiopulmonary bypass.

Dangers of postoperative hypothermia:

(1) It can lead to peripheral vasoconstriction and cause hypertension

(2) Cause bradycardia leading to decreased cardiac output, increased oxygen consumption and increased CO2 production, and if not adjusted in time, it is easy to cause hypercapnia, catecholamine release, tachycardia and pulmonary hypertension
.

(3) It can weaken the coagulation mechanism, platelet function and immune response, resulting in potential bleeding tendency and infection
after surgery.

(4) It is easy to induce chills

Precautions for rewarming:

Increased body temperature, usually at 36 ° C, vasoconstriction and hypertension

Replaced
by vasodilation, tachycardia, and hypotension.

Adequate volume during rewarming is helpful
in reducing rapid fluctuations in blood pressure.

5.
Postoperative myocardial ischemia

Wall motion score

The scoring method is as follows:

0 points = normal

1 point = slight motor function loss

2 points = severe hypomotor function with myocardial thickening

3 points = motor disorder

4 points = dyskinesia

6.
Postoperative hypertension

Hypertension is a common complication of cardiac surgery, reported in 30%~80% of patients
.

Although hypertensive patients are common in patients with a history of hypertension, hypertension can be developed in any patient
.

Arterial vasoconstriction with varying degrees of intravascular volume depletion is characteristic;

Factors associated with the development of hypertension:

Awakening under general anesthesia

Increase in endogenous catecholamines

Activation of the plasma renin-angiotensin system

Nerve reflexes (e.
g.
, heart, coronary arteries, large veins)

Risk factors for hypertension:

Inhibits left ventricular work

Increases myocardial oxygen demand

Increases the incidence of cerebrovascular disease

The sutures are cracked

Mitral regurgitation

arrhythmia

Increased bleeding

Treatment of hypertension

nitroglycerin

Adrenergic blockers such as phentolamine

β-blockers

α.
β receptor blockers
.

Dihydropyridine calcium channel blockers: nifedipine, diltiazem, nicardipine, iradipine, clovidipine;

ACE inhibitors

Dopamine receptor blockers: fenoldopam

Dihydropyridine blockers

Selectivity:

Nifedipine

Nicardipine half-life is 40 minutes

Clvidipine is underway as a new ultrashort-acting dihydropyridine

The third phase of research, with a half-life of only a few minutes, is likely in the future

Become an alternative to sodium nitroprusside
.

7.
Right heart failure

diagnosis

treat

8.
Cardiac tamponade

diagnosis

treat

(1) Replenishing blood volume and elevating the lower limbs can increase venous return
.

(2) The minimum tidal volume and minimum PEEP should be used, while increasing the systemic venous pressure,

(3) Sedatives and opioid analgesics should be given with caution as they may interfere with the release of adrenergic energy, causing sudden circulatory failure
.

Research progress in cardiovascular surgery and postoperative management

Postoperative management of postoperative complications of transcatheter aortic valve replacement

Vascular complications

stroke

Perivalvular leakage

Abnormal heart conduction

Echocardiography in the cardiothoracic intensive care unit

Part is drained from the inferior vena cava into ECMO, and after oxygenation,

Perfused from the femoral artery into the patient's body, the other part is refluxed from the superior vena cava to the right heart, through the patient's pulmonary oxygenation, into the left heart, through the left heart ejection, into the patient's arterial system;

If the patient's own lung function is insufficient, the blood oxygenated by the pulmonary circulation may be relatively hypoxic; If the patient's lung function is poor, the perfusion of the heart and brain will be hypoxic

Echocardiography in the cardiothoracic intensive care unit

Echocardiography to diagnose the phenomenon of north-south syndrome On echocardiography can be a "rotating" flow pattern of descending thoracic aorta stagnation caused by the return of blood from the 7 ventricles and outflow branches to the patient's interface: a north-south syndrome
in a patient with upper body hypoxemia.
The (A) short-axis view and (B) long-axis view of the descending aorta show an increase in spontaneous echogenic contrast (SEC) in the descending thoracic aorta, indicating stagnation
of blood flow.

Discontinuation of venous-arterial extracorporeal membrane oxygenation

summary

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