Management of Shock

Management of Shock

General Management

1. Attention to the management of ABCDEs- Suction may be required to remove any vomitus or secretions. If the airway is obstructed, extend the head, lift up the chin and insert an airway if the patient will tolerate it. In cervical cord injury is suspected jaw thrust is sufficient to clear air way. Give oxygen by mask 6 L/min. If the patient is not breathing adequately, ventilate with oxygen, using a mask or an ETT.
   
2. Positioning of the patient may be a valuable adjunct in the initial treatment of hypovolemic shock. Elevating the foot of the bed (i.e., placing it on shock blocks) and assumption of the Trendelenburg position without flexion at the knees are effective but may increase work of breathing and risk for aspiration. Simply elevating both legs may be the optimal approach.
   
3. Vascular access: once air way and breathing are supported; the priority in shock treatment is gaining vascular access for fluid resuscitation and medication.
   
4. Fluid resuscitation: Fluid therapy is an essential part of the treatment of any form of shock, the rationale being to improve microvascular blood flow by increasing plasma volume, and to increase cardiac output and tissue perfusion. However, too much fluid also carries risks, principally of pulmonary edema.
   

• The type of fluid: the selection being determined on an individual patient basis.
• The rate of fluid administration: It is important to define the amount of fluid to be administered over a defined interval. There are various recommendations of fluid challenges, for the management of severe sepsis and septic shock recommend 500-1000 mL of crystalloids or 300-500 mL of colloids over 30 minutes. 20 mL/kg fluid challenge in hypovolemic shock or with re-challenges of 5 - 10 mL/kg and 100 - 200 mL challenges in cardiogenic
• The goal to be achieved: The primary defect(s) that prompts the fluid challenge should be identified and quantitated so that a goal can be determined; most commonly this will be restoration of an adequate mean arterial pressure (greater than 70mmHg) or systolic blood pressure greater than 90 mmHg with clinical signs of peripheral perfusion.
• Safety limits: Pulmonary edema as a consequence of congestive heart failure is the most serious complication of fluid infusion. A safety limit, continuous assessment of lung, sclera, jugular vein oxygen saturation, must be set to avoid this complication. Repeated fluid challenges will enable help to continuously reassess a patient's ongoing fluid needs and limit the risks of adverse effects.

5. Maintain body temperature to normal: Hypothermia occurs secondary to inadequate tissue perfusion and poor oxygenation. At this point, the patient cannot control or maintain his/her own temperature.
   
6. Monitoring: Assess the effectiveness of fluid resuscitation and pharmacologic support by frequent continuous monitoring of the following:
   

• Oxyhemoglobin saturation with pulse oximetry
• Blood pressure and heart rate
• Mental status
• Temperature
• Urine out put

7. Frequent assessment: the condition of a patient especially child in shock is dynamic. Continuous monitoring and frequent reassessment of the respiratory, cardiovascular, and neurologic status are essential to evaluate trends in the child's condition and determine response to therapy.
   

Specific Management of Shock

Treatment of Hypovolemic Shock and Traumatic Shock

• Consider the general management of shock
• The initial management of the seriously injured patient requires attention to the ABCs of resuscitation: assurance of an airway (A), adequate ventilation (breathing, B), and establishment of an adequate blood volume to support the circulation (C). Control of hemorrhage requires immediate attention.
• Hypotension in patients with hypovolemic (hemorrhagic) shock should be aggressively treated with intravenous fluids and blood products, not vasopressors, unless there is profound hypotension that is unresponsive to fluid therapy, coexisting cardiogenic shock, or cardiac arrest
• Multiple short (1.5-2 inch), large-bore (14-16 gauge) cannula are placed in whichever veins are easily accessible. Peripheral lines are usually sufficient for initial resuscitation.
• Intravenous fluid resuscitation is the initial therapy for shock following injury. Even in critically ill trauma patients without ongoing hemorrhage, early and aggressive fluid replacement is associated with improved outcomes.
• Among the different crystalloid solutions available, lactated Ringer's is generally preferred over normal saline to avoid causing a hyperchloremic metabolic acidosis. Resuscitation with colloid fluids, such as albumin, is not commonly used. Dextrose-containing solutions may exacerbate ischemic brain damage and should be avoided in the absence of documented hypoglycemia. Even lactated Ringer's solution is slightly hypotonic and when administered in large volumes can aggravate cerebral edema.
• Persistent or worsening shock despite crystalloid therapy should prompt resuscitation with primarily blood products, starting with emergency type O packed red blood cells (PRBCs) until typed and cross matched products are ready for the patient. If available, whole blood with short storage duration is effective
• Colloid solutions (albumin, dextran, HES) are far more expensive than crystalloids, but they are more effective in rapidly restoring intravascular volume. Nonetheless, the interstitial fluid deficit associated with hypovolemic shock may be better treated with a crystalloid solution or a combination of colloids and crystalloids.
• Whichever fluid is chosen, it must be warmed prior to administration.
• Indicators of adequate fluid resuscitation include a urine output of 0.5 ml/kg/hour for adults and1 ml/kg/hr in children, maintenance of a mean arterial blood pressure of > 60- 70 mmHg, a decrease in heart rate, and normal pulse pressure.
• Shock that is refractory to aggressive fluid therapy may be due to uncontrolled hemorrhage that exceeds the rate of transfusion or to cardiogenic shock (eg, pericardial tamponade, myocardial contusion, myocardial infarction), neurogenic shock (eg, brain stem dysfunction, spinal cord transection), septic shock (a late complication), pulmonary failure (eg, pneumothorax, hemothorax), or severe acidosis or hypothermia. .
• Early stabilization of fractures, debridement of devitalized or contaminated tissues, and evacuation of hematoma all reduce the subsequent inflammatory response to the initial insult and minimize subsequent organ injury.

Treatment of Cardiogenic Shock

• Consider the general management of shock
• The goal is to increase contractility without significant increases in heart rate. Dopamine, norepinephrine, or vasopressin exerts both inotropic and vasoconstrictor actions that are useful in the presence of persistent hypotension.
• Pulmonary congestion or pulmonary edema may be responsive to intravenous furosemide.
• Referral in cases of refractory cardiogenic shock.
• Immediate pericardiocentesis for cardiac tamponade
• Chest decompression must be done for tension pneumothorax.

Treatment of Septic Shock

• Consider the general management of shock
• Aggressive volume expansion with a crystalloid solution
• Restoration of arterial oxygenation with inspired oxygen and frequently with mechanical ventilation is the highest priorities.
• In the presence of sepsis, augmentation of cardiac output may require inotropic support with dopamine (Renal dose 1-3 mic/kg/min), norepinephrine, or adrenaline
• Antibiotics should be administered, either appropriate for the results of cultures or empirical therapy based on the likely source of infection.
• Surgical debridement or drainage may also be necessary to control the infection

Treatment of Neurogenic Shock

• Consider the general management of shock
• Treatment involves a simultaneous approach to the relative hypovolemia and to the loss of vasomotor tone.
• Excessive volumes of fluid may be required to restore normal hemodynamic.
• Once hemorrhage has been ruled out, norepinephrine/epinephrine may be necessary to augment vascular resistance.

Treatment of Hypoadrenal Shock

• Consider the general management of shock
• In the hemodynamically unstable patient: dexamethasone sodium phosphate, 4 mg, should be given intravenously.
• Hydrocortisone 100 mg every 6 to 8 h, and tapered as the patient achieves hemodynamic stability.
• Simultaneous volume resuscitation and pressor support are required.

Treatment of Anaphylactic Shock

• Consider the general management of shock
• Rapidly administer pharmacologic support
• Epinephrine 0.01mg/kg
• Albuterol 0.5% for bronchospasm by intermittent nebulizer; 2.5 - 5mg/dose every 20 minutes or,
• Adrenaline nebulizer: Dose of 3-4 ml of 1:10,000 concentration added to nebulizer. Repeat this as needed.
• Antihistamine e.g., Diphenhydramine 1-2mg/kgIV/IM q 4-6 hrs maximum dose 50 mg
• Corticosteroids e.g., Methylpredinsolone 2mg/kg IV/IM loading, .5mg/kg q 6 hrs maintenance