Chapter 20 Shock

positive inotropic agents

increase contractility

Cardiogenic shock is characterized by

reduced cardiac output Occurs primarily as a result of severe dysfunction of the left or right ventricles or both, that results in inadequate cardiac pumping The low cardiac output state is associated with a high left ventricular filling pressure

The effect of nitric oxide on systemic arterioles is

vasodilation

In which stage of shock is a patient who has lost 1200ml of blood, who has normal blood pressure when supine, but who experiences orthostatic hypotension upon standing?

Class II - compensated stage - blood loss of 750 and 1500ml

Overproduction of nitric oxide is an important aspect of the pathophysiologic process of what type of shock?

Septic - due to release of immune cytokines

A pt with cold and edematous extremities, low cardiac output, and profound hypotension is likely to be experiencing a progressive stage of......... shock

Septic - in the progressive stage of septic shock- some pt's deteriorate to a hypodynamic state characterized by by decreased cardiac output and cold, clammy skin due narrowed pulse pressure

Improvement in a pt with septic shock is indicated by an increase in

Systemic vascular resistance

The progressive stage of hypovolemic shock is characterized by

Tachycardia Anxiety Low bp

Dobutamine (Dobutrex)

Used to decrease vascular resistance

Massive release of histamine with consequent vasodilation and hypotension occurs with what type of shock?

anaphylactic - exposure to a specific antigen causes receptors on mast cells and basophils to cross-link and activate histamine. The release of histamine along with other vasoactive chemicals produces bronchoconstriction

Sepsis has been recently redefined as

A systemic inflammatory response to infection

Low cardiac output in association with high preload is characteristic of......... shock.

Cardiogenic shock - preload is high and cardiac output is low

A patient presenting with fever, hypotension, and lactic acid is most likely to be experiencing which type of shock?

Septic

Class I - Initial stage of shock

Blood loss up to 750ml and pt's vitals remain normal

The majority of cases of anaphylactic shock occur when a sensitized individual comes in contact with

Antibiotics Anaphylactic shock is most frequently associated with antibiotic therapy

Tachycardia is an early sign of low cardiac output that occurs because of

Baroreceptor activity- a number of compensatory responses are set in motion to restore tissue perfusion and oxygenation in the early stage of shock Baroreceptors located in the aorta and carotid arteries quickly sense the decrease in pressure and transmit signals to vasomotor center in the brain stem medulla The sympathetic nervous system stimulates B1 receptors, which respond by increasing the heart rate in an attempt to increase cardiac output

Class III - Progressive stage of shock

Blood loss of 1500 and 2000ml - vital changes are changing

Positive inotropic drugs work by increasing

Contractility Cardiac output Tissue perfusion Myocardial oxygen demand

Lacted Ringers solution and normal saline are commonly used .........solutions that contain electrolytes

Crystalloid

Administration of which therapy is most appropriate for hypovolemic shock?

Crystalloids - solutions that contain electrolytes (isotonic solutions, such lactated ringers) - preferred for volume resuscitation, because they remain in the extracellular space and are more effective in increasing blood volume

Administration of a vasodilator to a patient in shock would be expected to

Decrease left ventricular afterload Vasodilators are used to decrease the workload of the heart by decreasing left ventricular afterload (nitroglycerin)

............. is a serious complication of septic shock characterized by abnormal clot formation in the microvasculature throughout the body

Disseminated intravascular coagulation

Septic shock is commonly associated with Gram neg and Gram pos organisms that enter the body through the

GI tract Genitourinary tract Respiratory tract Skin

In contrast to all other types of shock, the hyperdynamic phase of septic shock is associated with

High cardiac output - blood pressure falls because of the decreased systemic vascular resistance and decreased venous return

A pt experiences anaphylactic shock. The nurse expects to observe which signs and symptoms in the pt

Hypotension Angioedema Wheezing Urticaria Tachycardia Tachypnea Bronchoconstriction Laryngeal edema

B-adrenergic agonists

Increase tissue perfusion

Hypovolemic shock

Low preload and low cardiac output

Class IV - Refractory stage (severe hemorrhage)

More than 2000ml blood loss - to is lethargic, with severe hypotension

A type of shock that includes brain trauma that results in depression of the vasomotor center is

Neurogenic shock

Tumor necrosis factor (TNF) and interleukin-1 contribute to shock states because they induce production of

Nitric oxide

A pt who was involved in a fall from a tree becomes short of breath. The lung sounds are absent on one side. The pt is experiencing

Obstructive shock- as a result of a tension pneumothorax and is caused by shifting and compression of mediastinal structures including the heart, which compromises left ventricular filling

The urinary signs and symptoms of acute renal failure associated with the progressive stage of shock are

Oliguria Increased serum creatinine Increased blood urea nitrogen

Hypotension associated neurogenic and anaphylactic shock is due to

Peripheral pooling of blood - profound peripheral vasodilation of both arterioles and veins leads to peripheral pooling of blood and hypotension

Which causes of shock are considered to be obstructive

Pulmonary embolus Cardiac tamponade Tension pneumothorax

A pt experiencing shock may exhibit which signs and symptoms

Pulse of more than 100 beats/minute Fast and deep respiration's Cool, clammy skin Dilated pupils Decreased urinary output Increased urine specific gravity

A pt is diagnosed with cardiogenic shock. The pt is hyperventilating and is therefore at risk of the respiratory complication of

Respiratory alkalosis

Cardiac tamponade

Results from an accumulation of fluid in the pericardial sac causing elevation of pressures on both sides of the heart

tension pneumothorax

Results in shifting and compression of mediastinal structures including the heart, which compromises left ventricular filling