S HOCK ( صدمة )

O BJECTIVES By the end of this lecture, the students would be able to: Define shock. Identify types of shock. Determine stages of shock. Identify general signs and symptoms of shock. Identify care management for the types of shock.

I NTRODUCTION Shock is a state of inadequate delivery of blood (oxygen) and glucose (nutrients) to the cells. Shock is fatal ( قاتل ) if left untreated ( غير معالج ). In other words, Shock is a life-threatening condition that occurs when the body is not getting enough blood flow as a result of severe hypotension.

Shock requires IMMEDIATE ( فوري ) medical treatment. If not properly managed the tissue damage becomes irreversible ( لا يرجع لوضعه السابق ) and finally leads to multi-organ failure ( فشل في عدة أعضاء ). The body cells most sensitive to lack of oxygen are in the heart, brain, and lungs.

B ASIC C AUSES OF S HOCK Heart attack or heart failure to pump blood effectively. Severe or sudden blood loss. Large drop in body fluids [often from burns or dehydration ( جفاف )]. Blood vessels dilate, causing blood to pool in extremities ( الأطراف ) and non-vital areas Major infections. Long exposure to extreme heat or cold.

T YPES OF S HOCK Hemorrhagic (Hypovolemic) Shock Non-Hemorrhagic Shock 1. Cardiogenic Shock 2. Septic/Toxic Shock 3. Neurogenic Shock 4. Anaphylactic/Vasogenic Shock 5. Psychogenic Shock 6. Metabolic Shock

S TAGES OF S HOCK A progressive process that can be either gradual ( تدريجي ) or rapid ( سريع ). Throughout ( خلال ) the progression ( تعاقب الأمر ) of shock, the victim’s condition constantly changes 1. Compensated Shock صدمة مُعوّضة : The body works to overcome developing hypotension and hypoperfusion ( قلة توزيع الدم ). 2. Uncompensated Shock: Defense mechanisms are unable to compensate for the systemic decline ( تردّي وضعف شامل بأجهزة الجسم ) caused by poor circulation. 3. Irreversible ( غير معكوسة – دائمة ): The body is unable to overcome the effects of anaerobic metabolism ( أيض غير هوائي ). The death of vital organs occur.

C YCLE OF T RAUMATIC S HOCK

S HOCK ’ S G ENERAL S IGNS AND S YMPTOMS

H EMORRHAGIC (H YPOVOLEMIC ) S HOCK A sudden decrease in the volume of blood, resulting in decreased blood return. Most common cause is hemorrhage ( نزيف ) due to: (1) stab wounds جروح ناتجة عن طعنات, (2) gunshot wounds, and (3) motor vehicle accidents. Other causes for hypovolemic shock are: (1) dehydration (caused by: excessive vomiting and diarrhea), and (2) burns.

Without sufficient blood or fluid replacement, hypovolemic shock syndrome may lead to irreversible cerebral and renal damage ( ضرر دماغي وكلوي ), cardiac arrest ( توقف في عضلة القلب ) and, ultimately ( في نهاية المطاف ), death.

N ON -H EMORRHAGIC S HOCKS 1. Cardiogenic Shock صدمة قلبية المنشأ 2. Septic Shock صدمة إنتانية ( تسممية ) 3. Neurogenic Shock صدمة عصبية المنشأ ( بالجهاز العصبي ) 4. Anaphylactic Shock صدمة تحسسية /Vasogenic Shock صدمة وعائية 5. Psychogenic Shock صدمة نفسية المنشأ 6. Metabolic Shock صدمة أيضية

1. C ARDIOGENIC S HOCK It is a shock due to a decrease in contractions/contractile ability of the myocardium ( عضلة القلب ). The most common cause is myocardial infarction ( احتشاء عضلة القلب ( موتها with greater than 40 percent muscle necrosis ( موت ), in which the heart fails to circulate blood efficiently. Reduction in cardiac output results in: (1) decreased circulating blood supply, and (2) decreased oxygen delivery.

2. N EUROGENIC S HOCK It is a shock that results due to the failure of nervous system to control the diameter of blood vessels leading to decreased arterial resistance and peripheral vasodilatation. Common causes are: (1) nerve paralysis (spinal cord or brain injuries), (2) severe blows ضربات شديدة to the abdomen, (3) hot bath or hot vapor bath, (4) certain drugs, and (5) hypoglycemia causing vasomotor center depression ( تردي عمل المركز الحركي ).

3. A NAPHYLACTIC /V ASOGENIC S HOCK It is a shock that results from an extreme and generalized allergic antigen-antibody reaction ( تفاعل ضد مستضد ) that may bring on vascular collapse ( انهيار عمل وعائي المنشأ ). Within 30 minutes, these changes usually occur: (1) diffuse متفشي vasodilation (2) increase size of vascular bed ( منطقة التقاء الشُرَينات والوُرَيدات ), (3) the blood is trapped in small vessels and viscera ( أحشاء ), and (4) temporary loss in total circulatory volume.

The allergic antigen-antibody reaction causes widespread histamine release, which results in swelling of the lips and tongue, bronchioles constriction ( تضيق قصيبات هوائية ) (causing wheezing, stridor), decreased cardiac output and hypoxia, flushing, and pruritus ( حكة ).

Common causes are: (1) exposure to sensitive drugs or other substances (serum, vaccines enzymes, hormones, penicillin and other antibiotics, local anesthestetics, salicylates), (2) exposure to diagnostic chemicals (radiographic contrast dye), (3) sensitivity to certain food (legumes, nuts, berries, seafood, eggs), and (4) exposure to insect venom سم (honeybees, mosquitoes, certain spiders).

4. P SYCHOGENIC S HOCK It is a shock that results from a sudden dilation of the blood vessels takes place in response to an emotional or traumatic situation causing the patient to faint ( يصاب بالإغماء ). Stimulation of the vagus nerve ( العصب الحائر ) causes the heart to slow down (bradycardia). When the bradycardia is severe enough, insufficient blood flow to the brain results and the patient loses consciousness (faints).

Several conditions may cause psychogenic shock including: (1) severely scared situations, (2) severe exhaustion ( إعياء شديد ), and (3) hearing bad news (e.g.: death of someone, failure in an exam).

5. S EPTIC OR T OXIC S HOCK It is a condition that shows vascular dilatation due to a major infection. The biochemical mediators (such as the inflammatory mediators cytokines) cause a damage to the blood vessels walls, which lose their ability to constrict. Diseases and conditions that predispose a patient to septic shock include: (1) liver disease, and (2) immune suppression (AIDS, drug therapy for cancer).

6. M ETABOLIC S HOCK This shock occurs due to a change in blood chemistry. The change in the chemistry might be due to: (1) salt and acid-base balance, (2) failure of the adrenaline ( هرمون الأدرينالين – هرمون للغدة الكظرية ), thyroid glands ( غدد درقية ) and pituitary glands ( غدد نخامية ), and (3) diabetes mellitus ( داء السكري ).

M ANAGEMENT OF S HOCK Check Responsiveness. Activate the EMS system immediately. Check the person's circulation, airway, and breathing. If necessary, begin cardiopulmonary resuscitation (CPR) to prevent irreversible organ damage and death. Note: Even if the person is able to breathe on his or her own, continue to check rate of breathing at least every 5 minutes until help arrives.

Place the victim in a comfortable position. If the victim DOES NOT have an injury to the head, neck, or spine عمود فقري, elevate the victim legs 30 cm (Trendelenburg’s position), with the head turned to one side. DO NOT elevate the head.

Careful! Do NOT reposition the victim if there is a possibility of spinal or neck injuries. In Cardiogenic Shock: Place the victim flat. In case the victim complains of difficulty breathing, place the victim in semi- Fowler’s position.

Give appropriate first aid for any wounds, injuries, or illnesses. Keep the victim warm (but not hot). Prevent hypothermia. Minimize effect of shock. Loosen tight clothing. Provide oxygen therapy, if available.

T REATMENT H INTS Fluid therapy and drug therapy should be provided as soon as possible by trained health professionals.

In Anaphylactic/Vasogenic Shock: More attention should be paid to: Securing the airway. Assessing for dyspnea ( ضيق تنفس ), respiratory difficulty, cyanosis, wheezing ( الصفير خلال التنفس ) (can be life-threatening). Observing for vertigo ( دوار ), decreased blood pressure, and increased pulse. Terminating the exposure to causative agent. First-line therapies, during acute stage: (1) epinephrine, (2) IV fluids, and (3) oxygen. Second-line therapies include: (1) antihistamines, and (2) corticosteroids.

P OSITIONING V ICTIMS ON A L ONG B ACKBOARD

Three or more rescuers needed. 1. Position long backboard beside the victim. 2. One rescuer maintains head in line while other rescuers take position. 3. On cue from rescuer at the victim’s head, other rescuers roll the victim toward them as a unit.

4. Slide backboard next to the victim. 5. On cue ( عند الإشارة ) from rescuer at head, other rescuers roll the victim as a unit. 6. The victim is secured to backboard using straps ( روابط وأحزمة ربط )