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