1. Start BRM according to the algorithm described above. If there is only one rescuer, and there is already an AED at his disposal, start the BRM with the use of the AED.
2. Once the AED is delivered to the scene:
Turn on the AED and place electrodes on the victim's chest. If a second rescuer is present, continuous compressions should be continued during electrode placement. chest (????????);
Make sure that no one touches the victim during rhythm analysis - this may disrupt the rhythm analysis algorithm;
An automatic external defibrillator performs an automated analysis of the victim's rhythm using a specially developed computer algorithm: VF and pulseless VT are recognized as rhythms requiring defibrillation.
If defibrillation is indicated (VF or pulseless VT), make sure that no one is touching the victim and press the button (if the AED is in automatic mode, you do not need to press the button); after applying the shock, continue BRM in a ratio of 30:2 without delay; also follow the AED's voice and visual commands;
If defibrillation is not indicated, continue BRM at a 30:2 ratio without delay and follow the AED's voice and visual commands.
Lateral stable position:
Exist various options lateral stable position, each of which must ensure that the victim’s body is positioned on its side, free outflow of vomit and secretions from the oral cavity, and no pressure on the chest:
1. remove the victim’s glasses and put them in a safe place;
2. kneel down next to the victim and make sure that both his legs are straight;
3. move the victim’s arm closest to the rescuer to the side to a right angle to the body and bend it elbow joint so that her palm is turned upward;
4. Move the victim’s second hand across the chest, and hold the back of the palm of this hand against the victim’s cheek closest to the rescuer;
5. with your other hand, grab the victim’s leg farthest from the rescuer, just above the knee and pull it up so that the foot does not come off the surface;
6. holding the victim’s hand pressed to his cheek, pull the victim’s leg and turn him to face the rescuer into a side position;
7. bend the victim’s thigh to a right angle at the knee and hip joints;
9. check for normal breathing every 5 minutes;
10. transfer the victim to a lateral stable position on the other side every 30 minutes to avoid positional compartment syndrome.
Algorithm of measures for obstruction of the respiratory tract by a foreign body.
Most cases of foreign body airway obstruction are food-related and witnessed. Timely recognition of obstruction and differentiation from other conditions accompanied by acute respiratory failure, cyanosis and loss of consciousness.
The algorithm for providing assistance depends on the degree of obstruction.
With mild obstruction, a person can answer the question “Are you choking?”, speaks, coughs, breathes. In this case, it is necessary to maintain a productive cough and monitor the victim.
With severe obstruction, a person cannot answer a question, cannot speak, can nod, cannot breathe or breathes hoarsely, makes silent attempts to clear his throat, and loses consciousness. A common feature of all types of obstruction is that, if it occurs while eating, the person grabs the throat.
In case of severe obstruction with preserved consciousness, it is necessary to perform 5 blows to the back:
Stand to the side and slightly behind the victim;
Supporting the victim by the chest with one hand, tilt him forward with the other so that when the foreign body moves, it falls out of the mouth, rather than sinking deeper into the respiratory tract;
Apply up to five sharp blows with the heel of your palm to the area between the shoulder blades;
After each blow, check to see if the airway is clear; strive to ensure that each blow is effective, and try to achieve restoration of airway patency in fewer blows.
If 5 blows to the back are ineffective, it is necessary to perform 5 pushes to the abdominal area (Heimlich maneuver):
Stand behind the victim and grab him at the level of the upper abdomen with both hands;
Tilt his torso forward;
Make a fist and place it between the navel and the xiphoid process of the sternum;
Grasp your fist with your other hand and make a sharp push inward and upward;
Repeat the manipulation up to five times;
If the obstruction cannot be eliminated, repeat alternately five times blows to the back and pushes to the stomach.
If the victim loses consciousness, carefully place him on the ground, call emergency services and begin chest compressions, which will help expel the foreign body from the respiratory tract. When performing BRM in this case, each time the airway is opened, the oral cavity should be checked for the presence of a foreign body pushed out of the airway.
If, after the obstruction resolves, the victim continues to have a cough and difficulty swallowing, this may mean that parts of the foreign body are still in the airway, and the victim should be sent to a medical facility. All victims treated with back blows and abdominal thrusts should be hospitalized and assessed for injuries.
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There are various options for a lateral stable position, each of which should ensure that the victim’s body is positioned on its side, the free outflow of vomit and secretions from the oral cavity, and the absence of pressure on the chest (Fig. 19):
1. remove the victim’s glasses and put them in a safe place;
2. kneel next to the victim and make sure that both legs are straight;
3. move the victim’s arm closest to the rescuer to the side to a right angle to the body and bend it at the elbow joint so that the palm is turned upward;
4. Move the victim’s second hand across the chest, and hold the back of the palm of this hand against the victim’s cheek closest to the rescuer;
5. With your other hand, grab the victim’s leg farthest from the rescuer, just above the knee and pull it up so that the foot does not come off the surface;
6. holding the victim’s hand pressed to his cheek, pull the victim’s leg and turn him to face the rescuer into a side position;
7. bend the victim’s thigh to a right angle at the knee and hip joints;
9. check for normal breathing every 5 minutes;
10. transfer the victim to a lateral stable position on the other side every 30 minutes to avoid positional compartment syndrome.
Rice. 19.
Typical mistakes when carrying out basic and advanced resuscitation measures
Delay in starting CPR and defibrillation, loss of time on secondary diagnostic, organizational and therapeutic procedures.
Lack of a single leader, presence of outsiders.
Incorrect technique of chest compressions (infrequent or too frequent, superficial compressions, incomplete relaxation of the chest, breaks in compressions when applying electrodes, before and after applying a shock, when changing rescuers).
Incorrect artificial respiration technique (airway patency is not ensured, air tightness during air injection, hyperventilation).
Lost time searching for intravenous access.
Multiple unsuccessful attempts at tracheal intubation.
Lack of accounting and control of ongoing treatment measures.
Premature cessation of resuscitation measures.
Weakening of control over the patient after restoration of blood circulation and breathing
FEATURES OF RESUSCITATION MEASURES IN CHILDREN
Scheme 2.
The BRM algorithm for children has the following differences from the algorithm for adults:
BRM start with 5 artificial breaths. Only if the child has lost consciousness in front of witnesses and no one else is around, you can start BRM with 1 minute of chest compressions and then go for help;
When performing artificial respiration, a baby (child under 1 year old) should not straighten his head; You should cover the baby’s mouth and nose with your lips at the same time (Fig. 28);
Rice. 28.
After performing 5 initial artificial breaths, check for signs of restoration of spontaneous circulation (movements, cough, normal breathing), pulse (in infants - on the brachial artery, in older children - on the carotid artery; pulse on the femoral artery - in both groups), spending This should take no more than 10 seconds. If signs of restoration of spontaneous circulation are detected, artificial respiration should be continued if necessary. If there are no signs of spontaneous circulation, begin chest compressions;
Perform chest compressions on the lower part of the sternum (find the xiphoid process and move one finger width higher), to 1/3 of the depth of the child’s chest. In infants - with two fingers in the presence of one rescuer and using the circular method in the presence of two rescuers. In children older than one year - with one or two hands (Fig. 29-30);
Rice. 29.
Rice. thirty.
Continue CPR in a 15:2 ratio;
When providing assistance for airway obstruction by a foreign body, abdominal thrusts are not used due to the high risk of internal organ damage in infants and children;
Technique for performing back blows on infants: hold the child in a position with his back up, while his head should be pointing down; the rescuer sitting on the chair must hold the baby, placing him on his lap; support the baby's head by positioning thumb hands on the corner of the lower jaw and one or two fingers of the same hand on the other side of the jaw; do not squeeze the soft tissues under the lower jaw; apply up to five jerky blows between the shoulder blades with the base of the palm, directing the force of the blows cranially;
Technique for performing back blows in children over 1 year of age: blows will be more effective if the child is given a position in which the head is located below the body; small child can be placed above the knee bent leg across, just like infant; if this is not possible, bend the child’s torso forward and hit the back while standing from behind; If blows to the back are ineffective, you should move on to performing chest thrusts.
Chest thrusts in infants: Place the baby on his back so that the head is lower than the body. This is easily achieved by placing your free hand along the child's back, with the fingers covering the back of the head. Lower the hand holding the child below your knee (or over your knee). Determine the place where the pressure will be applied ( Bottom part sternum, approximately one finger above the xiphoid process). Perform five chest thrusts; the technique resembles an indirect cardiac massage, but is performed more abruptly, sharply and at a slower pace. Chest thrusts in children over 1 year old - according to the usual method.
The advanced resuscitation algorithm for children has the following differences from the algorithm for adults:
Use any air ducts with great care, since a child’s soft palate can be easily injured;
Tracheal intubation should be performed by an experienced specialist, since children have anatomical features of the larynx. Typically, uncuffed endotracheal tubes are used in children under 8 years of age;
If it is impossible to provide intravenous or intraosseous routes of drug administration, the intratracheal route should be used (adrenaline 100 mcg/kg, lidocaine 2-3 mg/kg, atropine 30 mcg/kg, diluted in 5 ml of saline);
Adrenaline in children is administered intravenously or intraosseously at a dose of 10 mcg/kg (maximum single dose 1 mg); amiodarone – 5 mg/kg;
Defibrillation:
Electrode size: 4.5 cm in diameter for infants and children weighing less than 10 kg; 8-12 cm in diameter - for children weighing more than 10 kg (over 1 year);
If, with the standard arrangement of electrodes, they overlap each other, the electrodes should be placed in an anteroposterior position;
Discharge power – 3-4 J/kg;
At the scene of the incident and during transportation, the victim must be given an optimal (advantageous) position that affects the function of vital organs. This situation depends on the type of injury and the severity of the victim’s condition:
In victims who are unconscious due to traumatic brain injury, poisoning, cerebrovascular accident, etc., there is always a danger of tongue retraction, and due to suppression of cough and swallowing reflexes, blockage of the airways with vomit, saliva, sputum, foreign bodies, blood (especially if the victim is on his back). This inevitably leads to impaired lung function in the form of asphyxia (suffocation). To prevent this, the victim must be immediately placed in a stable lateral (drainage) position (Fig. 9).
Fig.9 Drainage position to prevent asphyxia
- Remove the victim's glasses (if any).
- Kneel at the victim's side. Make sure his legs are straight and his arms are at his side.
- Take the victim's arm closest to you at a right angle to the body, bend it at the elbow so that the palm is directed upward.
- Place the hand farthest from you diagonally on the victim’s chest; Place the back of the victim’s hand on the victim’s cheek closest to you.
- With your other hand, grab the victim’s leg farthest from you, under the knee; turn the victim towards you so that bent knee the victim and his foot were resting on the ground.
- Straighten the victim's head so that the airway remains clear. If necessary, adjust the position of the palm on which the patient's head rests so that the airway remains clear.
- Monitor the victim's breathing.
Before turning the body, to prevent the risk of displacement of the cervical vertebrae (if they are fractured), it is advisable to fix the cervical spine with a cervical splint (Fig. 10).
Fig. 10 Neck splint
The “frog” position is used if a pelvic injury is suspected, lower limbs. The victim is placed on his back with his knees and knees apart and half bent. hip joints limbs that rest on the bolster in the popliteal region (Fig. 11).
Fig. 11 “Frog” position for injury to the pelvis and lower extremities
A patient with spinal injuries is placed in a supine position with a cushion placed on them (Fig. 12).
The horizontal position of the body with the legs elevated by 30 - 40 cm is used for massive blood loss and ongoing internal bleeding (Fig. 14).
We have already mentioned the stable side position several times. Today we will tell you in more detail about what this position is, as well as how and when it should be used.
Reading the material below will not make you an expert in first aid. This material is intended to stimulate interest in acquiring knowledge in this area and help correct typical mistakes. Practicing quality first aid skills requires the use of competent instructors, simulation material and dummies. Always seek qualified help in this matter!
The name itself suggests that a person lies on his side and it provides a certain level of stability, which serves the following purposes:
- A person lying in a stable lateral position is able to breathe freely even in an unconscious state. He is not in danger of tongue retraction, because even if the tongue moves under the influence of gravity, it will not block the airways. The chest is not loaded with the weight of the victim and can move freely during breathing movements.
- This position allows the victim to be comfortable using the ““ method, because you can easily bring your ear closer to the victim’s mouth and place your hand on his chest, checking the movements of the chest.
- A stable lateral position ensures freedom of movement, even in case of nausea or vomiting. If the victim were to vomit the contents of his stomach, the vomit would not accumulate in the mouth, blocking the airways. They will simply flow down one of the cheeks under the influence of gravity. Yes, the victim will not look very good, but he will be able to breathe, which is much more important for us.
- A stable lateral position provides a certain level of fixation for the victim and prevents further injury. The victim’s head is fixed, and the body, even in a completely relaxed state, does not shift or roll in any direction, which is very useful during transportation.
We may need the listed advantages in the following situations:
- Complete or partial loss of consciousness (confusion, risk of fainting).
- The victim is unconscious but breathing on his own.
- Suspicion or presence of head injuries, accompanied by dizziness and nausea.
- For some reason, you need to separate from the victim. In this case, a stable lateral position provides you with confidence that the victim will not suffocate due to tongue retraction, will not be injured by loss of consciousness, falling or displacement of the body, etc.
Perhaps the only situation where the stable lateral position cannot be used is back injuries and cervical region spine, in which unnecessary movements (turning on one side) can only aggravate the situation.
To transfer the victim from a supine position to a stable lateral position, there is a method that uses a system of levers created from parts of the victim's body. This method allows you to turn over victims who are significantly larger than you in weight and size, without requiring excessive physical effort. To use this method, just follow a number of simple steps described below:
- Kneel to the side of the victim.
- Position the victim's arm closest to you at a 90-degree angle to the body and bend it at the elbow. The palm of the hand should be oriented upward.
- With his eponymous hand ( right hand- right, left - left, depending on your position) take the victim’s hand farthest from you, palm to palm, locking your fingers. Move your far hand over the victim's chest and place it on the victim's cheek, which is closer to you. Hold it in this position.
- With your other hand, reach out to the victim’s leg farthest from you, and, grabbing it at the knee area, lift it relative to the victim’s body, bending it at the knee joint. The entire area of the victim’s foot should rest on the ground.
- Keeping the victim's hand pressed to the cheek and using the victim's far leg bent at the knee joint as a lever, turn it towards you, while controlling the victim's head. He should turn on his side to face you.
- Position the victim's upper leg so that the hip and knee are bent at right angles.
- Place the victim's hand under the cheek so that the head remains tilted back and face down, which will allow free flow of fluid from the oral cavity.
- Tilt the victim's head back (if it was not possible to do this at the previous stage), thereby providing better relief.
- Remove vomit from the victim's mouth as necessary.
- Check that top hand did not lie on top of the lower one, and did not cause compression of the soft tissues.
- Do not leave the victim unless there is a compelling reason, observe his condition and re-assess his breathing at least once every 5 minutes.
The title image of this publication illustrates all the stages of the algorithm described above.
SHAKE test
There's an answer
NO answer (unconscious)
Call the brigade by phone 112 (03)
Open the upper airway
Assess breathing (see, hear, feel)
Breathing normally
Stable side position
NOT BREATHING for the EMS team: identify Beloglazov
NOT BREATHING or breathing abnormally, choking
Sanitation of the upper respiratory tract
S-m Beloglazova (-)
Determine the pulse in the carotid arteries - only emergency medical services teams
NMS perform 30 compressions (frequency of at least 100 per minute)
NO chest excursion
Perform 2 artificial breaths
If there is a pulse, perform only mechanical ventilation.
IS chest excursion
NMS at least 100 per minute.
Ventilation 400-600 ml per breath
Rice. 1. Algorithm for performing a basic resuscitation complex.
Basic resuscitation is carried out by “first contact” persons, including medical workers without resuscitation equipment and medications. In emergency medical conditions, it is possible to carry out a basic set of CPR by a doctor or paramedic of a mobile team working without medical assistants. In the vast majority of cases, basic resuscitation is carried out outside a medical institution.
Survival during basic resuscitation depends on three main factors:
Early recognition of critical violations of the vital functions of the body and/or ascertainment of a state of clinical death.
Immediate initiation of resuscitation measures and their adequate implementation, primarily chest compressions (CCC) during the first 5 minutes from circulatory arrest.
Urgently call a resuscitation team to provide qualified assistance.
2.1. Algorithm for carrying out a basic resuscitation complex
Assess the risk to the resuscitator and the patient.
Make sure of your own safety, the safety of the victim and others. It is necessary to find out and, if possible, eliminate and/or minimize the risks for the resuscitator and the patient (heavy traffic, threat of explosion, collapse, electrical discharge, exposure to aggressive chemicals, etc.). If there is a threat to the life and health of the resuscitator, assistance should be delayed until the threat is eliminated.
Shake - test.
P Rice. 2. Checking the victim’s reaction.
If the victim responded to your stimuli by opening his eyes or speaking, leave him in the same position, try to find out the reasons for what is happening and call for help, while regularly assessing the condition of the victim.
In the absence of consciousness. Free your chest from outer clothing if this takes no more than 10 seconds.
Opening of the airways (5 sec).
Restoring the patency of the upper respiratory tract (URT) is carried out using a number of techniques that allow you to move the root of the tongue away from the back wall of the pharynx. The most effective, simple and safe for the patient are the following.
A. Method of throwing back the head and lifting the chin with two fingers (Fig. 3). One palm is placed on the patient’s forehead, two fingers of the other hand, placed in the middle of the chin part of the lower jaw, raise the chin, tilting the head back by pressing on the forehead. Thus, a mechanical obstacle to the air flow is eliminated.
Rice. 3. Opening of the VDP. Throwing back the head and raising the chin.
An alternative way to this technique is to tilt the head back by placing one hand under the patient’s neck and the other by pressing on the victim’s forehead.
B. Extension of the lower jaw without extension of the head in case of suspected injury to the cervical spine (Fig. 4). When clearing the airway in a patient with suspected cervical spine injury, lower limb advancement should be used. Rice. 4. Opening of the upper respiratory tract.
jaw without extension of the head in the cervical region. The resuscitator is placed on the side of the victim's head. The bases of the palms, which are located in the zygomatic region, fixes the head from possible displacement to the surface on which assistance is provided. II-V (or II-IV) with the fingers of both hands, grabs the branch of the lower jaw near the auricle and pushes it forward (up) with force. , With
hands opens the victim's mouth.
The horizontal ramus of the mandible should not be grasped, as this may lead to the mouth closing. The same method, but with simultaneous tilting of the head back, can be used if there is no suspicion of injury to the cervical spine (triple Safar maneuver).
Breathing assessment (10 sec). 
N
bend over the patient and for 10 seconds. (Fig. 5) watch the movement of the chest, listen to the breathing, try to feel the breathing (the “see, hear, feel” principle). If there is breathing, place the victim in a stable lateral position.
ABOUT
Determination of the pulse on the carotid artery is performed only by professionals or persons proficient in this technique. For
This causes the fingers of the hand, bent at the phalanges, to slide from the thyroid cartilage to the sternocleidomastoid muscle. The time to determine the pulse in the carotid artery should not exceed 10 seconds.
P 
If there is no breathing, the oral cavity and oropharynx are examined and sanitized. (Fig. 6)
If there are visible foreign bodies in the oral cavity and oropharynx, perform sanitation of the oral cavity/oropharynx. Dentures loosely located in the oral cavity, objects, mucus, vomit are removed strictly under visual control. Insert one or two fingers into the oral cavity with the pads facing the palate, rotate them 90° and remove the contents through the corner of the mouth with a traction movement.
Other upper respiratory tract toilet techniques:
A
b) the “finger behind the teeth” technique (insert a finger between the victim’s cheek and teeth and place its tip behind the last molars; used for tightly clenched teeth);
c) with the lower jaw completely relaxed, a “tongue and jaw lift” is used (the thumb is inserted into the victim’s mouth and pharynx and the root of the tongue is lifted with its tip; the lower jaw is grabbed with the other fingers of the same hand and lifted). Use fingers wrapped in cloth to clean the oropharynx, or use suction devices. The liquid contents may leak out on their own when you turn your head to the side (not applicable if a cervical spine injury is suspected!).
Checking the pupils - assessed only by professionals (10 sec).
The pupils are wide, do not react to light, the cat's pupil symptom (Beloglazov) is negative (in 2 eyes): when the eyeball is compressed from the outer to the inner corner, the pupil does not deform like a “cat”. This symptom appears after 15-30 minutes. from the onset of biological death (CPR is not advisable if the symptom is positive).
When a state of clinical death is established, it is necessary to call a specialized emergency resuscitation team (ICU team) as quickly as possible, and, if possible, bring (or ask others)automatic external defibrillator in parallel, begin carrying out the CPR complex.
If you have an automatic external defibrillator, connect the electrodes and follow the voice instructions of the device.
A precordial shock is performed only by professionals if circulatory arrest occurs in the presence of medical personnel with reliably established VT/VF in the first 10 seconds, that is, in a controlled situation, and before the defibrillator is ready to operate.
Applied once, the fist of the right (left) hand is compressed and raised to a height of about 20-30 cm. The fist is vigorously lowered, hitting the sternum with the elbow edge of the fist at the point of compression during chest compressions (see below for searching for the point). Then perform CPR immediately.
Basic resuscitation (BRM) begins with performing NMS with a compression rate of at least 100 per minute.
One cycle of CPR includes 30 chest compressions (CHC) followed by 2 mouth-to-mouth artificial breaths (MV). In this case, the resuscitator is on the side of the patient’s body on his knees, pressing his knees to the side surface of the patient’s body. The patient's arm on the resuscitator's side is moved to the side by 90 degrees. When performing BRM in confined spaces, compressions can be performed over the victim’s head or, if there are two rescuers, standing over the victim with legs apart.
T 
The compression point is located in the center of the chest, which corresponds to the lower half of the sternum strictly along the midline.
bend over the patient and for 10 seconds. (Fig. 5) watch the movement of the chest, listen to the breathing, try to feel the breathing (the “see, hear, feel” principle). If there is breathing, place the victim in a stable lateral position.
Rice. 7. Position of hands when performing NMS.
Pressure is applied to the chest in the anteroposterior direction to a depth of at least 5 cm, but not more than 6 cm, with a frequency of at least 100 per minute. In this case, the compression and decompression phases must be equal. It is necessary to ensure complete decompression of the chest without losing hand contact with the sternum after each compression. Chest compressions should only be performed on a hard surface.
Artificial respiration technique using the mouth-to-mouth method. Take a normal breath, pinch the victim’s nose with the thumb and forefinger of the hand placed on the forehead, while it is necessary to fix the victim’s head with the same hand behind the forehead. Using two fingers of the other hand, pull the chin behind the mental part of the lower jaw, thus ensuring the opening of the airway (Fig. 8A).
Having tightly clasped the patient's lips, two slow, smooth artificial breaths are taken, lasting 1 second and with an approximate volume of 500-600 ml (Fig. 8B).
Artificial inspiration is not forced.
The criterion for the effectiveness of artificial inhalation is the presence of a rise of the chest during inhalation and a fall of the chest after inhalation.
During artificial respiration, it is recommended to use barrier devices (protective screens, a face mask with a one-way air movement valve - Pocket Mask) placed at the entrance to the patient's oral cavity.
Rice. 8. Performing mechanical ventilation using the “mouth to mouth” method.
When carrying out the primary resuscitation complex by persons without medical education and in the absence of the possibility of performing artificial respiration at the beginning of resuscitation, it is possible to carry out the first six (approximately 2 minutes) cycles of CPR without mechanical ventilation. Medical workers, if they have the necessary tools, must perform mask ventilation with the introduction of an air duct using an Ambu-type bag.
Perform 6 cycles of CPR (180 compressions, 12 breaths), which is approximately 2 minutes.
In the future, when performing CPR, checking the pulse in the carotid artery is performed every 6 cycles (approximately 2 minutes).
Transfer the patient to a stable lateral position.
Kneel down next to the victim and make sure both legs are straight.
Move the victim’s arm closest to the rescuer to the side to a right angle to the body and bend it at the elbow joint so that the palm is turned upward.
Move the victim’s other hand across the chest, and hold the back of the hand of this hand against the victim’s cheek closest to the rescuer.
With your other hand, grab the victim’s leg farthest from the rescuer, just above the knee, and pull it up so that the foot does not lift off the surface.
Keeping the victim's hand pressed to the cheek, pull the victim's leg and turn him to face the rescuer into a side position.
Bend the victim's thigh to a right angle at the knee and hip joints.
Check for normal breathing every 5 minutes.
Place the victim in a lateral stable position on the other side every 30 minutes to avoid positional compartment syndrome.
Rice. 10. Stable lateral position.
If breathing is not restored to normal levels, further intensive therapy is carried out aimed at maintaining the patency of the upper respiratory tract and prosthetic respiratory functions (introduction of an air duct, Combitube tube, laryngeal mask, mask ventilation using an Ambu bag, ventilators with inhalation of 100% oxygen).