What Factors Increase Cardiac Arrest Survival?

Cardiac arrest refers to the sudden termination of the ejection function of the heart, the disappearance of aortic pulses and heart sounds, and severe ischemia and hypoxia of important organs (such as the brain), leading to the termination of life. This unexpected sudden death is also called sudden death in medicine. Ventricular fibrillation is the most common cause of cardiac arrest. If the patient is called for no response, and there is no response to the compression of the supraorbital and suborbital, it can be determined that the patient is in a coma. Pay attention to observe the patient's chest and abdomen for undulating breathing movements. If there is no pulsation in the carotid and femoral arteries, and no heartbeat can be heard in the precardiac area, it can be determined that the patient has a cardiac arrest.

Basic Information

English name

cardiacarrest

Visiting department

Cardiology

Common causes

Ventricular fibrillation

Common symptoms

Touch the carotid and femoral arteries, no heartbeat can be heard in the precardiac area

Causes of cardiac arrest

The common causes of cardiac arrest in the 2005 Cardiopulmonary Resuscitation and Cardiovascular Rescue Guide of the American Heart Association are summarized as follows: O2 deficiency. Hypokalemia / hyperkalemia and other electrolyte abnormalities. Low temperature / high body temperature. low blood volume. Hypoglycemia / hyperglycemia. Drugs. Heart pack stuffing. pulmonary embolism. Coronary blood vessel embolism. pneumothorax, asthma.

Clinical manifestations of cardiac arrest

The clinical course of cardiac arrest or sudden cardiac death can be divided into 4 periods: prodromal, morbid, cardiac arrest and death.

Precursory period

Many patients have prodromal symptoms, such as angina pectoris, shortness of breath, or palpitations, days or weeks, or even months before the onset of cardiac arrest, prone to fatigue and other non-specific complaints. These prodromal symptoms are not unique to sudden cardiac death but are common before any heart attack. Some data show that 50% of sudden cardiac death patients have been consulted within one month before the sudden death, but their main complaint is not necessarily related to the heart. Among survivors of cardiac arrest outside the hospital, 28% had angina pectoris or increased dyspnea before cardiac arrest. However, prodromal symptoms only indicate the risk of cardiovascular disease, and cannot identify those subgroups with sudden cardiac death.

2. Onset period

That is, the period of acute cardiovascular changes leading to cardiac arrest usually does not exceed 1 hour. Typical manifestations include: long-term angina pectoris or chest pain with acute myocardial infarction, acute dyspnea, sudden palpitations, persistent tachycardia, dizziness, etc. If a sudden cardiac arrest occurs without warning in advance, 95% of the cases are cardiogenic and have coronary artery disease. From the continuous ECG records obtained by sudden cardiac death, it can be seen that there are often changes in ECG activity within hours or minutes before sudden death. Among them, the rapid increase in heart rate and the deterioration of premature ventricular beats are the most common. Sudden death from ventricular fibrillation is usually preceded by a sustained or non-sustained ventricular tachycardia. Most of these patients with arrhythmia are awake before onset and in daily activities, the onset period (from onset to cardiac arrest) is short. ECG abnormalities are mostly ventricular fibrillation. Another part of the patients developed circulatory failure. They were inactive or even unconscious before cardiac arrest, and their onset was long. Noncardiac diseases often exist before dying cardiovascular changes. Electrocardiogram abnormalities are more common with ventricular arrest than ventricular fibrillation.

3. cardiac arrest

The complete loss of consciousness is characteristic of this period. If not rescued immediately, it usually enters the death period within a few minutes. Rarely spontaneous reversals.

Cardiac arrest is a sign of clinical death, and its symptoms and signs are as follows: the heart sound disappears; the pulse cannot be touched and the blood pressure cannot be measured; sudden loss of consciousness or short-term convulsions, which are usually systemic and mostly occur in the heart Within 10 seconds after apnea, sometimes with eye deflection; breathing is intermittent, sighing, and then stop. Occurred within 20 to 30 seconds after cardiac arrest; coma, occurred more than 30 seconds after cardiac arrest; mydriasis, mostly occurred 30 to 60 seconds after cardiac arrest. But this period has not yet reached biological death. If timely and appropriate rescue is available, there is a possibility of recovery.

The success rate of resuscitation depends on: sooner or later the start of resuscitation; the place where cardiac arrest occurs; the type of arrhythmia (ventricular fibrillation, ventricular tachycardia, electromechanical separation, ventricular pause); Clinical situation of patients before stopping. If cardiac arrest occurs in a place where cardiopulmonary resuscitation can be performed immediately, the success rate of resuscitation is high.

Under the condition that the hospital or the intensive care unit can be rescued immediately, the success rate of resuscitation mainly depends on the clinical situation of the patient before cardiac arrest: if it is an acute cardiac condition or a temporary metabolic disorder, the prognosis is better; if it is chronic Late-stage or severe non-cardiac conditions (such as renal failure, pneumonia, sepsis, diabetes, or cancer) have no greater success rate for resuscitation than out-of-hospital cardiac arrest. The success rate of the latter mainly depends on the type of ECG during cardiac arrest. Among them, ventricular tachycardia has the best prognosis (67% success rate), followed by ventricular fibrillation (25%), ventricular arrest and electromechanics. The prognosis for separation is poor. Older age is also an important factor affecting the success of recovery.

4. Biological death

The evolution of cardiac arrest to biological death mainly depends on the type of cardiac electrical activity and the timeliness of cardiac resuscitation. Ventricular fibrillation or ventricular arrest, if the cardiopulmonary resuscitation is not given within 4 to 6 minutes, the prognosis is poor. If cardiopulmonary resuscitation is not performed within 8 minutes, there is almost no survival except under special circumstances such as low temperature. According to statistical data, the immediate implementation of cardiopulmonary resuscitation and early defibrillation by witnesses is the key to avoiding biological death. The most common cause of death during hospitalization after CPR is damage to the central nervous system. Hypoxic brain injury and infections secondary to long-term use of respirators account for 60% of causes of death, low cardiac output accounts for 30% of causes of death, and only 10% of those die due to recurrence of arrhythmia. The prognosis of cardiac arrest in patients with acute myocardial infarction depends on whether it is primary or secondary: the former is not hemodynamically unstable when the cardiac arrest occurs; the latter is secondary to an unstable hemodynamic state. Therefore, if the primary cardiac arrest can be resuscitated immediately, the success rate can reach 100%; while the prognosis of the secondary cardiac arrest is poor, the recovery rate is only about 30%.

Cardiac arrest examination

ECG performance

1. Ventricular fibrillation or flutter, accounting for about 91%;

2. ECG mechanical separation, wide and deformed, low amplitude QRS, frequency of 20 to 30 times / minute, no mechanical contraction of myocardium;

3. The ventricle is at rest, showing a straight line without electric waves, or only atrial waves. Ventricular fibrillation did not return to cardioversion for more than 4 minutes, and almost all turned to ventricular rest.

Cardiac arrest diagnosis

1. Loss of consciousness.

2. The carotid and femoral pulses disappeared, and the heart sounds disappeared.

3. Sigh-like breathing. If the blood circulation cannot be restored urgently, stop breathing quickly.

4. The pupil is dilated, and the reflection of light weakens and even disappears.

Cardiac arrest treatment

1. Initial and secondary recovery

(1) Restore effective blood circulation Immediate chest heart compression. The main points are: the patient lies on his back, with the ground or hard board on his back, the operator's palms overlap, the elbows are straight, and the shoulder force is used to press the middle of the middle and lower 1/3 of the patient's sternum vertically to make the lower part of the sternum sink about 4cm The frequency is 70 to 80 times / minute. ECG monitoring, if ventricular fibrillation, DC defibrillation is performed. adrenaline: first intravenous injection, if it is too late to establish a venous channel can be injected intracardiacly or trachea. If it is difficult to defibrillate for a while, or if the defibrillation is not repeated at one time, intravenous injection of amiodarone, lidocaine, brombeam, or procainamide can be used. Drug defibrillation and electrical defibrillation are used alternately at the same time. Can improve the success rate of recovery. If the ventricle is stationary during ECG monitoring, isoproterenol can be added intravenously, and it can be repeated after 3 minutes. If the ventricular stasis medication is ineffective, perform thoracic cardiac pacing as soon as possible, or temporary intracardiac pacing via vein. Resuscitation is still ineffective for 20 minutes. You can open the chest and press the heart, and continue medication until hopeless.

(2) Immediately unblock the airway and artificial respiration when breathing stops. Tilt the patient's head back, raise the chin, and remove foreign body in the mouth. Tight mouth joint artificial respiration, pinch the patient's nostrils when blowing. If the patient's teeth are closed tightly, blow to the nose deliciously to make the patient's chest swell effective. 12 to 16 breaths per minute. Cardiac compressions are performed alternately at 1: 5 or 2:10. Inhale oxygen. If spontaneous breathing is not restored within 15 minutes, mechanical ventilation should be used for tracheal intubation as soon as possible, and respiratory stimulants are not recommended to avoid increasing cerebral oxygen consumption or causing convulsions.

(3) Correct acidosis In the past, conventionally, a large amount of sodium bicarbonate was used in the past. However, the modern principle of use is: it is better not to be late than to be less, but not more to owe. Because the main reason for acidosis during cardiac arrest is hypoperfusion and C0 ₂ accumulation, a large amount of intravenous sodium bicarbonate can increase tissue C 0 ₂ and the blood is overly alkaline, which shifts the Hb oxygenation curve to the left and inhibits and releases oxygen. Hypoxia of tissues can inhibit the function of myocardium and brain cells, cause high sodium and hypertonic states, and reduce the success rate of resuscitation. Therefore, it is best not to use it before establishing stable blood circulation and effective ventilation.

If a cardiac arrest patient occurs outside the hospital, a manual resuscitation operation should be performed on site, and an emergency treatment should be escorted to a nearby medical unit for second-stage resuscitation as soon as possible.

2. Post-recovery treatment

Cardiac arrest first aid

(1) Maintenance of blood circulation After cardiac resuscitation, there is often hypotension or shock. Blood volume should be appropriately supplemented and vasoactive drugs should be used to maintain blood pressure at normal levels.

(2) Maintain effective ventilation function Continue to inhale oxygen. If spontaneous breathing has not recovered, continue to use an artificial respirator; if spontaneous breathing recovers but is not sound and stable, use a breathing stimulant, such as nicosamide, stilbamine or Huisuling intramuscularly or intravenously; To actively prevent respiratory infections.

(3) ECG monitoring Arrhythmia is found to be handled as appropriate.

(4) Active brain resuscitation If the cardiopulmonary resuscitation takes a long time, the brain function will be damaged to varying degrees, manifested as a disturbance of consciousness, a residual mental and mobility impairment, and even a vegetative form. Therefore, brain resuscitation is the focus of the later stage. If the consciousness is accompanied by fever, the head of the head should be cooled; if the blood pressure is stable, artificial hibernation can be performed. Chlorpromazine and promethazine are usually given intravenously or intramuscularly. Prevention and treatment of cerebral edema: use dehydrating agent, adrenal glucocorticoid or albumin as appropriate. Drugs for improving brain cell metabolism: such as ATP, coenzyme A, cerebrolysin, citicoline, etc. oxygen radical scavenger. Hyperbaric oxygen chamber treatment.

(5) Protect renal function Closely observe urine output and blood creatinine to prevent and treat acute renal failure.

3. First aid measures

Rescue of cardiac arrest must be against time, never wait for an ambulance to arrive before being sent to hospital for treatment. Take the following first-aid measures immediately for CPR.

(1) Press one hand on the chest to support the patient's neck and back, and the other hand to hold the patient's forehead to push it back slightly, so that the lower jaw is tilted, and the head is tilted back, which is beneficial for ventilation. Do chest chest compressions. Ask the patient to pad a hard board on the back while doing mouth-to-mouth artificial respiration. Observe the patient's pupils. If the pupils diminish (the most sensitive and meaningful sign of life), the face and lips turn ruddy, indicating that the rescue is effective.

(2) Acupuncture acupuncture points in the middle of the human body or Laogong acupoint of the palm of the hand and Yongquan acupoint of the foot to play a rescue role.

(3) Quickly pull out the vomit from the pharynx to avoid clogging the airways or flowing back into the lungs, causing suffocation and aspiration pneumonia.

(4) Cool the ice pack on your head.

(5) Emergency delivery to hospital for treatment.

Cardiac arrest prognosis

In patients with successful cardiac arrest and resuscitation, it is important to assess left ventricular function in a timely manner. Compared with patients with normal left ventricular function, patients with left ventricular dysfunction are more likely to have a recurrence of cardiac arrest, respond poorly to antiarrhythmic drugs, and have a higher mortality rate.

The primary ventricular fibrillation in the early stage of acute myocardial infarction is a non-hemodynamic abnormality, and it is easy to achieve cardioversion after timely defibrillation. Cardiac arrest due to bradyarrhythmia or ventricular arrest due to acute inferior myocardial infarction has a good prognosis. In contrast, acute extensive anterior myocardial infarction with cardiac arrest due to atrioventricular or intraventricular block often has a poor prognosis.

Cardiac arrest secondary to acute large-area myocardial infarction and hemodynamic abnormalities has an immediate mortality rate of 59% to 89%, and cardiac resuscitation is often difficult to succeed. Even if the resuscitation is successful, it is difficult to maintain a stable hemodynamic state.