NUR 445 Exam 2 Questions With Complete Solutions

What is the definition of affinity? - AND the attraction between Hgb and O2 What does Hgb have an affinity to? - ANS Hgb has an attraction for O2 molecules What does the oxyhemoglobin dissociation curve represent? - ANS relationship between PaO2 and SaO2 What is PaO2? - ANS partial pressure of arterial O2 (arterial O2 tension) What is SaO2? - ANS Hgb saturation What does P50 represent? - ANS measures when Hgb is 50% saturated with O2 When does the P50 change? - ANS when physiologic factors are altered What does a left shift on the dissociation curve do to the affinity of O2 to hemoglobin? - ANS increases affinity = prevents release to tissues What does a right shift on the dissociation curve do to the affinity of O2 to hemoglobin? - ANS decreases affinity = readily release to tissues What causes a left shift on the dissociation curve? - ANS alkalosis, hypothermia, hypocapnia, decreased 2,3 DPG What causes a right shift on the dissociation curve? - ANS acidosis, hyperthermia, hypercapnia, increased 2,3-DPG What are three components of oxygenation? - ANS pulmonary gas exchange, O2 delivery, O2 consumption What 2 problems in oxygenation does the nurse assess for and intervene? - ANS decreased O2 supply, increased O2 demand What is the definition of oxygenation? - ANS the use of O2 for energy through aerobic metabolism What are the two goals in the assessment of oxygenation? - ANS to determine the overall adequacy of oxygenation and to determine which component of oxygenation dysfunction should be manipulated What are the three components of pulmonary gas exchange? - ANS ventilation, diffusion, perfusion What is the definition of ventilation? - ANS movement of air between the atmosphere and the lungs What is the actual work of breathing called (using the muscles, lungs, airway, nervous system)? - ANS ventilation What is the definition of diffusion? - ANS movement of gas across pressure gradient from area of high concentration to low concentration What is it called when O2 moves from alveoli to pulmonary capillaries? - ANS diffusion What is the definition of perfusion? - ANS pulmonary perfusion of pulmonary capillaries; flow of blood to tissues/organs What is perfusion affected by? - ANS Hgb, O2 affinity, and blood flow Why is the matching of ventilation to perfusion essential for gas exchange? - ANS when they are not matched, oxygen becomes impaired When might ventilation to perfusion mismatching occur? - ANS PE, pneumothorax, hypoxemia What are the components of oxygen delivery? - ANS CO, CaO2, ANS innervation, auto-regulation What is afterload? - ANS resistance ventricle pumps blood What is the normal value for afterload? - ANS 800-1200 What is cardiac output? - ANS amount of blood pumped each minute What is the normal value for cardiac output? - ANS 4-8 What is CaO2? - ANS Total O2 carried in arterial blood What is the combination of SaO2 and PaO2? - ANS CaO2 What is contractility? - AND the force of contractions What is DO2? - ANS process of O2 transport to cells, utilizing CO, CaO2, autoregulation, and ANS innervation What is the product of CO and CaO2? - ANS DO2 What is HgbO2? - ANS hemoglobin fully saturated with O2 What is SaO2/SpO2? - ANS ratio of HgbO2 to total Hgb What is the difference between SaO2 and SpO2? - ANS SpO2 means obtained through pulse oximetry, where SaO2 is via arterial blood What is stroke volume? - ANS volume pumped with each beat What is the normal value of stroke volume? - ANS 50-100 What is the normal value of Hgb? - ANS 12-17 What does PaO2 represent? - ANS amount of oxygen dissolved in plasma What does SaO2 represent? - ANS Saturation of Hgb with O2 (oxyhemoglobin) What is the percentage of the body's oxygen on HgbO2 (SaO2)? - ANS 97% What percentage of the body's oxygen is dissolved in plasma (PaO2)? - ANS 3% What can impair O2 delivery? - ANS dysrhythmias, heart failure, uncompensated decrease in CO, Hgb, or SaO2 How is O2 delivery assessed? - ANS CO, Hgb, SaO2, PaO2 (ABGs) How can CO be assessed at the bedside? - ANS pulses, heart sounds, monitor, fluid balance, CVP, heart sounds, O2 status, BP, pulse pressure, Hx of previous MI, acute MI or ischemia What is the definition of oxygen consumption? - ANS the rate at which O2 is used by cells to generate energy What is the definition of aerobic metabolism? - ANS carbs/fats/proteins broken down into ATP (through Krebs cycle); creates intracellular energy stores to release when energy is required What is the definition of anaerobic metabolism? - ANS backup mechanism to generate energy in the absence of O2; this occurs through the metabolism of carbs, the only food that can generate ATP without oxygen What are byproducts of anaerobic metabolism? - ANS pyruvate and lactate What can a patient develop if anaerobic metabolism persists? - ANS ischemic stroke, cardiac arrest, lactic acidosis What is oxygen extraction? - ANS when cells take O2 from the blood What % of O2 is taken up by the cells? - ANS 25% What % of O2 is returned to the right heart? - ANS 75% What is SvO2? - ANS blood returned to the heart through venous circulation Are tissue demands higher or lower with a left shift on the oxyhemoglobin curve? - ANS lower Are tissue demands higher or lower with a right shift on the oxyhemoglobin dissociation curve? - ANS higher How does a left shift on the oxyhemoglobin dissociation curve affect tissue oxygenation? - ANS increases affinity of Hgb for O2, Hgb binds with O2 (high HgbO2/SaO2), Hgb does not readily release oxygen, so less O2 is extracted and cells become hypoxic, more O2 remains in blood as it flows back to heart through venous system What assessments are associated with a left shift on the oxyhemoglobin dissociation curve? - ANS High SaO2, SpO2, SvO2 What are some precipitating conditions for a left shift on the oxyhemoglobin dissociation curve? - ANS environmental exposure (cold-water near drowning, cold weather exposure, induced hypothermia from surgery); hyperventilation; GI-associated loss of acid or gain of alkaline through vomiting or NG drainage; sodium bicarbonate How does a right shift on the oxyhemoglobin dissociation curve affect tissue oxygenation? - ANS decreases affinity of Hgb for O2, Hgb doesn't bind as readily with O2 (HgbO2/SaO2), Hgb readily releases O2, O2 extracted rapidly, leaving insufficient O2 for all tissue, less O2 remains in blood as it flows back to heart through venous system What assessments are associated with a right shift on the oxyhemoglobin dissociation curve? - ANS Low SaO2, SpO2, SvO2 What are some precipitating conditions for a right shift on the oxyhemoglobin dissociation curve? - ANS respiratory failure, high fever, metabolic acidosis What happens to oxygen consumption if a patient has a fever, infection or increased work of breathing? - ANS may be 2x the resting O2 consumption What conditions are associated with increased O2 consumption? - ANS hyperventilation, hyperthermia, trauma, sepsis, anxiety, stress, hyperthyroidism, increased muscle activity What conditions are associated with decreased O2 consumption? - ANS hypoventilation, hypothermia, sedation, neuromuscular blocking agents, anesthesia, hypothyroidism, inactivity How should a nurse care for a patient with decreased O2 consumption? - ANS assessment, repositioning, dressing change, bed bath, weighing on sling bed scale, visitors, and avoid restlessness/agitation How can you measure oxygen consumption? - ANS serum lactate levels, base deficit, and venous oxygen saturation monitoring What is a normal lactate level? - ANS less than 2 How must a serum lactate level be interpreted? - ANS cautiously in patients with cancer, liver failure, renal disease, or alcoholism because these levels can rise without necessarily having worsening O2 delivery When does a base deficit result? - ANS from an imbalance between O2 delivery and O2 consumption = lactic acidosis secondary to anaerobic metabolism What is the normal range for a base deficit? - ANS +2 to -2 What does a positive base deficit indicate? - ANS metabolic alkalosis What does a negative base deficit indicate? - ANS metabolic acidosis Why is a great base deficit a concern? - ANS higher than 15 is associated with 70% mortality rate What do abnormally low SvO2 values mean? - ANS less O2 is returning to the right heart = cells not getting enough O2 to meet their needs What is the clinical significance of a low SvO2? - ANS blood transfusion (if low Hgb), inotropic drug therapy (if low CO) What causes decreased SvO2? - ANS decreased supply and increased consumption What causes increased SvO2? - ANS increased supply and decreased consumption What are some examples of decreased supply causing decreased SvO2? - ANS decreased CO, HF, hypovolemia, dysrhythmias, cardiac depressants (BBs, etc), decreased O2 sats, respiratory failure, pulmonary infiltrates, suctioning, ventilator disconnection, decreased hemoglobin, anemia, hemorrhage What are some examples of increased supply causing increased SvO2? - ANS increased CO, inotropic drugs, intra-aortic balloon pump, afterload reduction, increased O2 sats, increased FiO2 (inspired O2), improvement in lung problems, increased Hgb, blood transfusion What are some examples of increased consumption causing decreased SvO2? - ANS hyperthermia, seizures, shivering, pain, increased WOB, increased metabolic rate, exercise, education What are some examples of decreased consumption causing increased SvO2? - ANS hypothermia, fever reduction, sepsis (late stages), paralysis, pain relief, anesthesia What is the definition of shock? - ANS a syndrome, a complex presentation of s/sx that describe a sequence of changes that occur when tissue O2 supply does not meet O2 demand What are the types of shock? - ANS cardiogenic, hypovolemic, obstructive, and distributive (Semitic, neurogenic, anaphylactic) When does shock occur? - ANS when O2 delivery does not support tissue demands How does the body's SNS respond to the development of shock? - ANS Increases HR, RR, glycolysis, gluconeogenesis, mobilization of free fatty acids, decreased UO, blood flow to internal organs (kidneys/GI, liver), intestinal peristalsis, cool skin, diaphoresis What are the stages of shock? - ANS Initial, compensatory, progressive, refractory What is the initial stage of shock? - ANS decreased CO and perfusion = anaerobic metabolism and lactic acidosis What is the compensatory stage of shock? - ANS neuroendocrine responses are activated to restore CO and O2 delivery; compensatory s/s are evident What is the progressive stage of shock? - ANS major dysfunction of many organs; continued low blood flow, poor tissue perfusion, inadequate O2 delivery, buildup of metabolic waste What is the refractory stage of shock? - ANS organs resistant to conventional therapies; profound hypotension and death is inevitable What are the objective parameters of shock? - ANS arterial pH - determines acidosis/alkalosis; serum lactate - result of anaerobic metabolism; base excess and deficit - reflects metabolic acid-base; venous oxygen saturation - SvO2 What is a normal pH? - ANS 7.35-7.45 What are some interventions to optimize O2 delivery? - ANS oxygen therapy and fluid resuscitation What are some interventions to decrease O2 consumption? - ANS decrease total body work, reduce pain/anxiety, maintain normothermia, maintain normal serum glucose level What is a nurses' role in the management of shock? - ANS frequent hemodynamic and oxygenation assessments, assess for continued or renewed bleeding, warmed fluids, correct fluid replacement, I/Os, s/s of dehydration, IV insertion and assessment, patient comfort and pain, DVT prevention, H2 inhibitors, PPIs, heparin, family communication When are vasopressors used in the treatment of shock? - ANS to increase BP through constriction of peripheral vasculature What are some common catecholamine vasopressors? - ANS norepinephrine (levophed, levarterenol), dopamine; a and b receptors What are some common non-catecholamine vasopressors? - ANS Phenylephrine (neo-synephrine) - a1 When might you use an inotrope in shock? - ANS to manipulate contractility and CO What are some common inotropic medications? - ANS dobutamine and milrinone When does cardiogenic shock occur? - ANS heart fails to function as a pump to deliver oxygenated blood to the tissues What is the most common cause of cardiogenic shock? - ANS left-sided STEMI What are some other causes of cardiogenic shock? - ANS papillary muscle rupture, mitral or aortic stenosis, ventricular septal rupture, end-stage cardiomyopathy, myocarditis, severe heart contusion What are the hemodynamic criteria for diagnosing cardiogenic shock? - ANS sustained hypotension (systolic 90 for 30 minutes), elevated PAWP (15), low cardiac index (2.2) What are some common clinical findings associated with cardiogenic shock? - ANS chest pain, pulmonary congestion, dyspnea, bilateral crackles, reduced mentation, mottled and cool skin, diaphoresis, weak peripheral pulses, tachycardia Which diagnostic tests may be completed to confirm cardiogenic shock? - ANS ECG, ECHO, cardiac enzymes, CXR, ABGs, BMP What are nursing and medical interventions directed toward in managing a patient in cardiogenic shock? - ANS Decrease myocardial demand, improve myocardial supply; emergency interventions What are some initial management interventions? - ANS Reduce pulmonary edema, increase systemic BP and CO, prevent or control dysrhythmias, intubation and ventilation, decrease demand, protect airway, thrombolytic therapy, IABP, percutaneous LVAD, veno-arterial extracorporeal membrane oxygenation, revascularization (angioplasty, CABG) What management interventions would need to be done to support circulation? - ANS vasopressors, inotropic agents, diuretics, hemodynamic monitoring, aortic counterpulsation, percutaneous LVAD, venoarterial extracorporeal membrane oxygenation What does an IABP do? - ANS invasive technology that reduces afterload and augments coronary perfusion (= increased CO and improved coronary flow) What might some patients need who have advanced cardiogenic shock refractory to IABP, PCI, or CABG? - ANS surgically placed percutaneous LVADs or venoarterial extracorporeal membrane oxygenation (VA ECMOs) What are some clinical manifestations of LSHF? - ANS dyspnea, bilateral crackles, distant heart sounds, third or fourth sounds, elevated PAWP, low cardiac index (CI), sustained systolic hypotension What are some clinical manifestations of RSHF? - ANS peripheral edema, split S2 sounds, elevated RAP, normal or low PAWP What is the outcome for a patient in cardiogenic shock? - ANS optimize cardiac output What are some interventions for a patient in cardiogenic shock? - ANS assess and compare to established norms, patient baselines and trends, implement interventions to optimize O2 delivery, implement interventions to decrease O2 consumption, administer medications What interventions can optimize O2 delivery in a patient in cardiogenic shock? - ANS administer supplemental O2, IV fluids, inotropic agents (dobutamine), vasodilators, implement IABP What interventions can decrease O2 consumption in a patient in cardiogenic shock? - ANS mechanical ventilation, sedatives, analgesics, anxiolytics, reduce pain and anxiety, comfort measures, calm and quiet environment What medications can be helpful in cardiogenic shock? - ANS diuretics, vasodilators, inotropic agents, thrombolytic therapy How does hypovolemic shock occur? - ANS trauma and surgical high acuity patients What is the most common form of hypovolemic shock? - ANS hemorrhagic shock What are some clinical manifestations of hypovolemic shock? - ANS hypotension (lower as loss increases), low CVP, RAP, PAWP, PAP, CO, venous capacitance, high HR, SVR, SVV (stroke volume variation), low UO, cool, clammy, poor capillary refill, peripheral pulses faint or absent What are the treatment priorities for a patient experiencing hypovolemic shock? - ANS secure airway, support breathing, control bleeding, restore fluid volume, ABCs with blood and fluid What are the three types of distributive shock? - ANS septic, anaphylactic, and neurogenic What do distributive shock states involve? - ANS impaired oxygenation d/t altered blood flow distribution What, regardless of underlying cause, is the primary characteristic of all forms of distributive shock? - ANS massive vasodilation What is the SIRS criteria? - ANS HR90, T38, RR20, WBC12, procalcitonin or CR-P 2+ deviations normal What is considered severe sepsis? - ANS organ dysfunction, hypoperfusion, hypotension, lactic acidosis, oliguria, acute change in mental status What is septic shock? - ANS hypotension despite fluid resuscitation, perfusion abnormalities (lactic acidosis, oliguria, acute change in mental status) What are the major nursing priorities for a patient with sepsis? - ANS administer antibiotics within 1 hour after order, but blood cultures obtained prior to; obtain serum-lactate level, SvO2 above 70% What is the goal of CVP for fluid resuscitation in a septic patient? - ANS greater than 8 mmHg (or 12 in ventilated patients) What is neurogenic shock associated with? - ANS acute spinal cord injury What are the two types of neurogenic shock? - ANS spinal shock and neurogenic shock What is the triad of expected signs of neurogenic shock? - ANS hypotension, bradycardia, hypothermia Why do the triad of expected signs of neurogenic shock happen? - ANS persistent vasodilation, prevented reflex tachycardia and dysrhythmias, sweating is absent below level of injury, lost sympathetic innervation and unopposed parasympathetic innervation What are the treatment strategies for patients in neurogenic shock? - ANS maintain stability of the spine, optimize O2 delivery, restore intravascular volume, continuous cardiac monitoring (meds to increase HR), airway and ventilation support What values will you see in a patient in neurogenic shock with a PA catheter? - ANS low SVR, CVP, PAP, PAWP, and CO What is anaphylactic shock? - ANS severe systemic allergic reaction to allergens (food, drugs, blood, insect venom, latex) What is the pathophysiology of anaphylactic shock? - ANS massive amounts of histamine and kinins are released from mast cells, which flood the circulation with mediators and lead to systemic vasodilation and increased capillary permeability. This allows fluid to shift from vessels into the interstitium which causes life threatening edema and hypovolemia = decreased venous return, decreased CO, and decreased O2 delivery What are the clinical manifestations of anaphylactic shock? - ANS hypotension, upper airway obstruction (angioedema, tongue or laryngeal edema, laryngospasm), flushing, urticaria, pruritus, abdominal cramping, diarrhea (rapid or gradual onset) What are the immediate goals for treatment? - ANS maintain airway, support blood pressure, O2 administration, early intubation if distressed, fluid resuscitation, drug therapy, and anything to treat the specific problem What is the first line therapy for treatment of anaphylactic shock? - ANS epinephrine, methylprednisolone, prednisone, diphenhydramine, ranitidine, albuterol, ipratropium bromide What are some nursing implications of epinephrine? - ANS first line therapy; restore vascular tone and BP; repeat every 5 minutes PRN What are some nursing implications of methylprednisolone? - ANS severe allergic reaction; inhibits release of allergic substances What are some nursing implications of prednisone? - ANS mild allergic reaction; inhibits release of allergic substances What are some nursing implications of diphenhydramine? - ANS blocks histamine release at receptor sites What are some nursing implications of ranitidine? - ANS blocks histamine release at receptor sites What are some nursing implications of albuterol? - ANS bronchodilation What are some nursing implications of ipratropium bromide - ANS bronchodilation; when bronchospasm is refractory to B-agonist therapy When do obstructive shock states occur? - ANS mechanical barrier to blood flow that blocks O2 delivery to tissues What are some major causes? - ANS pulmonary embolism, tension pneumothorax, cardiac tamponade What is a PE? - ANS clot, air, or tissue that obstructs blood flow through any part of the lungs What are the most frequent signs and symptoms of PE? - ANS dyspnea, tachypnea, pleuritic pain, cough, wheezing, crackles, tachycardia, DVT, apprehension, fever, unilateral leg pain and swelling (DVT finding), hemoptysis, shock What is a tension pneumothorax? - ANS collapse of an area of lung caused by increased pressure in the thoracic cavity What are some clinical manifestations of tension pneumo? - ANS decreased venous return and CO, chest pain, air hunger, respiratory distress, absent lung sounds on affected side, tracheal deviation What is cardiac tamponade? - ANS medical emergency that puts pressure on heart, compressing heart wall and restricting heart actions What is pulsus paradoxus? - ANS decrease of systolic BP during inspiration (greater than 10 mmHg) What is MODS characterized by? - ANS progressive dysfunction of two or more organ systems What do SIRS denote? - ANS systemic inflammation regardless of its cause When the underlying cause of SIRS is infection, what is it called? - ANS sepsis What are the 4 prominent explanations for pathologic changes associated with MODS? - ANS uncontrolled systemic inflammation, tissue hypoxia, unregulated apoptosis, microvascular coagulopathy What is a major focus of nursing care to prevent SIRS and sepsis? - ANS meticulous hand hygiene and universal precautions What nursing pieces are key to improving patient outcomes with SIRS sepsis and MODS? - ANS continuous monitoring of physiologic parameters, early recognition of changes, early interventions What are 4 priority goals to treat or prevent MODS? - ANS identify and treat infections, glycemic control, correct hypoxia and hypotension, impaired tissue oxygenation What are the outcomes for a patient with MODS? - ANS optimize pulmonary gas exchange and tissue perfusion What are the interventions for a patient with MODS? - ANS parameters and SOFA score, respiratory assessment, VS, end-tidal CO2, ABGs, sputum culture, antibiotic peak and trough levels, ventilation settings and parameters, HOB 30 degrees, promote rest/comfort/relieve pain/anxiety, improve diaphragm excursion, tracheal suctioning, antibiotics, bronchodilators, peripheral assessment, hemodynamic monitoring, ECG, O2 therapy, IV fluids, sedatives/analgesics/anxiolytics, inotropic meds, vasoconstrictors What are three important homeostatic activities of the normal coagulation process? - ANS platelet activation, clot formation, and fibrinolysis What are some clinical manifestations of DIC? - ANS petechiae, ecchymoses, bleeding, oozing from arterial line, catheters, injured tissues, GI tract, lungs, or CNS bleeding, cyanosis, ischemia, gangrene on fingers/nose/ears, oliguria, anuria, azotemia, hematuria, transient hypoxemia, pulmonary hemorrhage, ARDS, delirium, coma, cerebral hemorrhage, meningeal irritation, jaundice, necrosis, gangrene What is the imperative treatment of DIC? - ANS vigorously treat the underlying disease What are some interventions for DIC? - ANS volume replacement, correct hypotension, blood components (platelets/cryo, FFP), heparin, treat underlying disease What are some nursing considerations for patients in DIC? - ANS supportive care; early s/s of complications (kidney, lung, brain), and internal bleeding; bleeding and micro-thrombosis related clinical manifestations Where is the carina? - ANS at the junction of the Y formed by 2 primary bronchial branches Why is the carina clinically significant? - ANS when touched by a suction catheter or endotracheal tube, it can trigger a bronchospasm or severe coughing What two things keep lungs from collapsing? - ANS surfactant and the thorax What are the pleura? - ANS slick surfaced, moist membranes What is the parietal pleura? - ANS adheres to thoracic wall, mediastinum, and diaphragm What is the visceral pleura? - ANS adheres to lung parenchyma Why are the pleura important? - ANS as the thorax increases/decreases in size, the lungs increase/decrease in volume What happens to the work of breathing with decreased compliance? - ANS increased work of breathing Which pulmonary problems cause decreased lung compliance? - ANS pneumonia, pulmonary edema, pulmonary fibrosis, pneumothorax What is air trapping? - ANS abnormal retention of air in the lungs on exhalation What is the definition of respiration? - ANS process by which body's cells are supplied with O2 and CO2 is eliminated from the body What is external respiration? - ANS movement of gases across alveolar-capillary membrane (pulmonary gas exchange) What is internal respiration? - ANS movement of gases across systemic capillary cell membranes in the tissues (systemic gas exchange) What are the five factors that affect diffusion through the alveolar-capillary membrane? - ANS partial pressures, gas gradient, lung surface area, alveolar-capillary membrane thickness, length of gas exposure in lungs What plays a role in determining the affinity of oxygen to hemoglobin which directly affects diffusion? - ANS oxyhemoglobin dissociation curve How much pressure does oxygen in the alveoli exert? - ANS 100 mmHg What is the difference between PaO2 and PvO2? - ANS arterial vs venous O2 tension How much pressure does carbon dioxide on alveoli exert? - ANS 40 mmHg What does PCO2 represent? (PaCO2 and PvCO2) - ANS carbon dioxide tension (arterial or venous) Why is the carbon dioxide content higher in PvO2 than oxygen? - ANS CO2 is the major waste product of cellular metabolism and is transported through the blood for removal by the lungs What two circulatory systems are involved with perfusion? - ANS systemic and pulmonary What factors is pulmonary perfusion dependent on? - ANS adequate perfusion in the systemic system What is the minimal MAP for perfusing MAJOR organs? - ANS 60 mmHg What balance needs to occur for normal diffusion of gases? - ANS alveolar ventilation (movement of gas into alveoli) and pulmonary perfusion (blood flow through pulmonary capillaries) How is the relationship of ventilation to perfusion expressed? - ANS V/Q ratio What is the average V/Q ratio? - ANS 4:5 What does a high V/Q ratio mean? - ANS normal to increased alveolar ventilation associated with decreased perfusion How does a high V/Q ratio affect alveolar gas exchange? - ANS increased CO, decreased alveolar CO2, exists in upper lung fields When is a high V/Q ratio abnormal? - ANS decreased CO, pulmonary emboli, pneumothorax, destruction of pulmonary capillaries How will ABGs look in a high V/Q ratio? - ANS increased pH and PaO2, decreased PaCO2 What does a low V/Q ratio mean? - ANS decreased alveolar ventilation associated with normal or increased perfusion How does a low V/Q ratio affect alveolar gas exchange? - ANS decreased O2 in alveoli, increased CO2 in alveoli, exists in lower lung fields When is a low V/Q ratio abnormal? - ANS hypoventilation, obstructive or restrictive lung disease How will ABGs look in a low V/Q ratio? - ANS decreased pH and PaO2, increased PaCO2 How does prolonged bed rest affect perfusion? - ANS blood is gravity dependent, so it shifts from lung bases to whichever lung is in the dependent position; but air is still drawn to diaphragm How does prone positioning affect a patient in ARDS? - ANS improves oxygenation What is a pulmonary shunt? - ANS percentage of CO that flows from the right heart into the left heart without undergoing pulmonary gas exchange What does anatomic shunt refer to? - ANS blood that moves from the right heart into the left heart without coming into contact with alveoli What conditions are associated with an anatomic shunt? - ANS VSD, trauma, lung tumors What is a capillary shunt? - ANS normal flow of blood past completely unventilated alveoli; blood flowing by affected alveoli does not take part in diffusion What conditions are examples of a capillary shunt? - ANS atelectasis, consolidation, or fluid in alveoli What is an absolute shunt? - ANS combined amount of anatomic shunt and capillary shunt What is the hallmark of ARDS? - ANS refractory hypoxemia What is refractory hypoxemia? - ANS hypoxemia that is not significantly affected by administration of increasing levels of O2 (absolute shunt) What occurs with a shuntlike effect? - ANS shunting is not complete; excess perfusion and reduced ventilation What are common causes of shuntlike effects? - ANS bronchospasm, hypoventilation, pooling of secretions What is a method to calculate intrapulmonary shunt? - ANS PaO2/FiO2 What 3 main factors determine the amount of PVR? - ANS length of vessels, radius of vessels, and viscosity of blood Which is the major determinant of PVR? - ANS vessel radius (caliber) What is PVR altered by? - ANS volume of blood in pulmonary vascular system, amount of pulmonary vasoconstriction, and degree of lung inflation What are the causes of pulmonary vasoconstriction (increased PVR)? - ANS alveolar hypoxia, decreased pH, alveolar hypercapnia, positive pressure ventilation, histamine, prostaglandin, angiotensin, catecholamines, SNS stimulation What is the normal PVR range? - ANS 50-150 Why does pulmonary vasoconstriction occur? - ANS in response to hypoxia, hypercapnia, acidosis What is cor pulmonale? - ANS right ventricular hypertrophy and dilation (secondary to pulmonary disease) What is the ratio of bicarbonate to carbon dioxide? - ANS 20:1 What is the definition of an uncompensated A/B disturbance? - ANS abnormal pH with one abnormal value and one normal value A pH of 7.2, PaCO2 of 60, and HCO3 of 24 is an example of what level of compensation? - ANS uncompensated respiratory acidosis What is the definition of a partially compensated A/B disturbance? - ANS abnormal pH with 2 abnormal values (PaCO2 and HCO3 in opposite directions) A pH of 7.3, PaCO2 of 60, and HCO3 of 30 is an example of what level of compensation? - ANS partially compensated respiratory acidosis What is the definition of a compensated A/B disturbance? - ANS normal pH with 2 abnormal values A pH of 7.38, PaCO2 of 50, and HCO3 of 30 is an example of what level of compensation? - ANS chronic compensated acidosis What is the definition of a corrected A/B disturbance? - ANS normal pH with 2 normal values (no acid/base disturbance) A pH of 7.36, PaCO2 of 43, and HCO3 of 26 is an example of what level of compensation? - ANS corrected What is respiratory acidosis? - ANS when pH drops below 7.35 and PaCO2 rises above 45 What indicates alveolar hypoventilation? - ANS high CO2 (hypercapnia) What are common causes of respiratory acidosis? - ANS oversedation, overdose, brain injury, respiratory muscle fatigue, neuromuscular disease, mechanical ventilation, altered diffusion or V/Q mismatch (pulmonary edema, severe atelectasis, pneumonia, severe bronchospasm) What is respiratory alkalosis? - ANS pH is greater than 7.45 and PaCO2 falls below 35 What indicates alveolar hyperventilation? - ANS Low CO2 What are common causes of respiratory alkalosis? - ANS hypoxia, brain injury, fever, overventilation, pain, anxiety, fear What is the definition of base deficit? - ANS measure of the amount of buffer required to return the blood to a normal pH state; excess of fixed acids or deficit of base in blood (metabolic acidosis state for deficit, alkalosis for excess) What is metabolic acidosis? - ANS pH less than 7.35 and HCO3 less than 22 What are common causes of metabolic acidosis? - ANS diabetic acidosis (elevated ketones), uremia (high phosphates and sulfates), ingestion of acidic drugs (aspirin), lactic acidosis, diarrhea, GI fistulas, loss of body fluids below umbilicus (except foley), laxative overuse, hyperaldosteronism What other conditions besides shock cause lactic acidosis? - ANS severe dehydration, severe infection, severe trauma, diabetic ketoacidosis, hepatic failure What is metabolic alkalosis? - ANS pH greater than 7.45 and HCO3 is greater than 26 What are common causes of metabolic alkalosis? - ANS N/V, NG suction, steroids (mineralocorticoids), diuretics, binge-purge syndrome What is the normal range for pH? - ANS 7.35-7.45 What is the normal range for PaCO2? - ANS 35-45 What is the normal range for HCO3? - ANS 22-26 What is the normal range for PaO2? - ANS 80-100 What is the normal range for SaO2? - ANS 95-100% What is the normal range of Hgb? - ANS 12-15 (girls); 13.5-18 (boys) What are the steps in determining A/B and O2 status? - ANS pH, PaCO2, HCO3, determine status, PaO2, SaO2, Hgb, evaluate patient What values are indicative of mild hypoxemia? - ANS PaO2 60-75 What values are indicative of moderate hypoxemia? - ANS PaO2 45-59 What values are indicative of severe hypoxemia? - ANS PaO2 45 What is the definition of tidal volume? - ANS amount of air that moves in/out of lungs with each normal breath What is the definition of vital capacity? - ANS maximum amount of air expired after a maximal inspiration What is minute ventilation? - ANS total volume of air expired in 1 minute during exhalation What does forced expiratory volumes (FEVs) measure? - ANS how rapidly a person can forcefully exhale air after a maximal inhalation, measuring volume in liters over time (in seconds) Why is forced expiratory volume (FEVs) used? - ANS helps differentiate restrictive from obstructive pulmonary problems and measures airway resistance, as well as determining the severity of obstructive diseases What are three methods of monitoring gas exchange? - ANS pulse oximetry, capnography, and arterial line What are some causes of inaccurate pulse oximetry readings? - ANS motion artifact, external light sources, improper sensor placement, Hgb level, acid-base imbalance, vasoconstriction, cardiac dysrhythmias What is capnography? - ANS noninvasive monitoring on a graphic display of CO2 concentration that is exhaled by the patient during breathing Is capnography the same as end tidal CO2 monitoring? - ANS Yes What does capnography measure? - ANS end tidal CO2 (EtCO2) What is a normal EtCO2 range? - ANS 30-45 What is the definition of restrictive pulmonary disorder? - ANS decreased lung compliance, expansion, and volume d/t disease of parenchyma, pleura, chest wall, or neuromuscular system (decreased total lung capacity) What are some common external problems related to restrictive pulmonary disorders? - ANS obesity, myasthenia gravis, muscular dystrophy, guillain-barre syndrome, spinal cord trauma, extensive chest burns, scoliosis, flail chest What are some common internal problems related to restrictive pulmonary disorders? - ANS pneumonia, atelectasis, heart failure, pulmonary edema, pulmonary fibrosis, pulmonary tumors, pneumothorax, asbestosis What are some clinical manifestations of restrictive pulmonary disorders? - ANS increase RR, SOB, cough, chest pain/discomfort, fatigue, weight loss, normal or decreased PaO2, decreased tidal volume What is the definition of obstructive pulmonary disorders? - ANS pulmonary condition that hinder expiratory air flow What are some of the major obstructive pulmonary disorders? - ANS emphysema, chronic bronchitis, asthma, cystic fibrosis What are some clinical manifestations of obstructive disorders? - ANS excess mucus, wheezing, rhonchi, dyspnea, diminished breath/heart sounds, barrel chest, progressive hypercapnia, respiratory acidosis, progressive or episodic hypoxemia, cor pulmonale, accessory muscle use, increased expiratory time (expiration time longer than inspiration time), PFTs = normal to increased TLC, increased functional residual capacity (FRC), decreased forced expiratory volume (FEV), decreased vital capacity What are some characteristics of restrictive disorders? - ANS decreased lung expansion and compliance, normal air flow How are PFTs affected in restrictive disorders? - ANS decreased TLC and VT What pathological disturbances cause restrictive disorders? - ANS decreased functioning alveoli, loss of pulmonary tissue and respiratory muscle strength; disorders that decrease lung compliance external to the lungs What ABG disturbances are found in restrictive disorders? - ANS decreased PaO2, normal or low V/Q ratio, increased intrapulmonary shunt, increased PaCO2, decreased pH if ventilatory pump failure is present What do lung sounds of restrictive disorders sound like? - ANS rhonchi if secretions build up in large airways What are some characteristics of obstructive disorders? - ANS increased lung expansion and compliance, decreased expiratory air flow, prolonged expiratory time How are PFTs affected in obstructive disorders? - ANS decreased forced expiratory volumes (FEVs) What pathological disturbances cause obstructive disorders? - ANS bronchoconstriction, bronchospasm, airway edema, airway obstruction, airway collapse, pooling of copious secretions What ABG disturbances are found in obstructive disorders? - ANS increased PaCO2, decreased pH, normal to decreased PaO2 (may stay stable until severe disease state) What do lung sounds of obstructive disorders sound like? - ANS wheezes, rhonchi, diminished breath sounds What is status asthmaticus? - ANS acute severe asthma where symptoms do not respond to drug therapy What are some major findings of status asthmaticus? - ANS pulsus paradoxus (25+ mmHg), accessory muscle use, significant lung hyperinflation, ABG show hypoxemia with/out hypercapnia, reduced peak expiratory flow rate (FEV1 of 30% or less), sudden onset of decreased wheezing, reduced/no breath sounds, coma, confusion, inability to speak, one word phrases, fatigue What is an ominous finding of status asthmaticus? - ANS sudden decrease in wheezing or loss of breath sounds = complete airway obstruction from mucus plug and impending cardiopulmonary arrest How is asthmaticus treated? - ANS O2, IV corticosteroids, inhale heliox, repeated albuterol What do beta agonists do? - ANS stimulates B2 adrenergic receptors in lung What conditions do beta agonists help with? - ANS COPD, asthma, exercise-induced asthma What are some effects of beta agonists? - ANS tachycardia, hypertension, tremors, potential paradoxical response of increased bronchospasm, hypokalemia (in high doses) What are some nursing implications regarding beta agonists? - ANS document HR, BP, response, side effects, educate on correct use of inhaler/spacer/nebulizer, metered dose or dry powder or small volume nebulizer What do anticholinergic bronchodilators do? - ANS bronchodilator; maintenance for COPD What are some effects of anticholinergic bronchodilators? - ANS poor absorption via inhalation limits systemic side effects (anxiety, dizziness, headache, nervousness), cough, dry mouth What are some nursing implications of anticholinergic bronchodilators? - ANS document HR, BP, response, side effects, avoid eye exposure, consider soy base and ensure no allergies, caution in patients with glaucoma or prostatic hypertrophy, correct use of inhaler/spacer/nebulizer, metered dose or dry powder or small volume nebulizer What do corticosteroids do? - ANS anti-inflammatory for airway edema (asthma, COPD) What are some effects of corticosteroids? - ANS insomnia, mood changes, HTN, high BS, low K, fluid retention, adrenal suppression, poor wound healing, GI bleeding, immune suppression, infection, acute adrenal insufficiency, cough, hoarse voice, bronchospasm What are some nursing implications regarding corticosteroids? - ANS can be given IV, oral, or inhaled depending on acuity; used as controller, use with spacer or reservoir, oral hygiene, avoid stopping abruptly, monitor for adrenal insufficiency (hypotension, shock) What do methylxanthines do? - ANS bronchodilation, stimulates ventilation, potential anti-inflammatory What are some effects of methylxanthines? - ANS tachycardia, dysrhythmias, anxiety, insomnia, seizures, tremors, N/V, anorexia What are some nursing implications of methylxanthines? - ANS serum theophylline levels, toxicity common, I/Os, HR, BP, cardiac rhythm, assess for therapeutic effect/side effects What do mucolytics do? - ANS decreases viscosity of secretions; used for cystic fibrosis, bronchitis What are some effects of mucolytics? - ANS bronchospasm, bad odor/taste, nausea, pharyngitis, chest pain What are some nursing implications of mucolytics? - ANS assess cough clearance, bronchospasm, side effects What do pulmonary vasodilators do? - ANS improve oxygenation, rescue hypoxemia, reduce pulmonary HTN What are some effects of pulmonary vasodilators? - ANS hypotension, methemoglobinemia, headache, flushing, jaw pain What are some nursing implications of pulmonary vasodilators? - ANS monitor HR, BP, therapeutic effects, side effects, observe for rebound pulmonary HTN, hypoxemia What is respiratory insufficiency? - ANS state in which an acceptable level of gas exchange is maintained only through cardiopulmonary compensatory mechanisms What are the clinical signs & symptoms suspicious of impending respiratory failure? - ANS tachypnea, tachycardia, increased use of accessory muscles, nasal flaring, abnormal chest wall movements, labored breathing, decreasing SpO2, diaphoresis, orthopneic, air hunger, anxiety What is the definition of respiratory failure? - ANS caused by an imbalance in supply and demand, develops when cardiopulmonary system is unable to maintain adequate gas exchange What are the two component parts of acute respiratory failure? - ANS failure of oxygenation and failure of ventilation What is the definition of oxygenation failure? - ANS hypoxemia; CO2 diffuses across membrane 20x more rapidly than O2 The primary problem in oxygenation failure is what? - ANS hypoxemia What is the definition of ventilatory failure? - ANS acute respiratory acidosis; inability to move air into the alveoli, which decreases O2 exchange = buildup of CO2 What are the clinical manifestations of ventilatory failure? - ANS tachypnea, headache, flushed, wet skin, bounding pulse, HTN, tachycardia, lethargy, drowsiness, coma Why is ventilatory failure sometimes called CO2 narcosis? - AND the effect that CO2 has on LOC Why is ventilation failure considered a worse problem than oxygenation failure? - ANS acute respiratory acidosis can quickly deteriorate to systemic acidosis What are the clinical criteria for acute respiratory failure? - ANS acute respiratory failure = PaCO2 50, pH 7.3, PaO2 60 oxygenation failure = PaO2 60 ventilation failure = PaCO2 50, pH 7.3 What are the management goals for the patient in acute respiratory failure? - ANS treat underlying cause, support the patient, prevent/treat complications What are some common predisposing factors of ARDS? - ANS pneumonia, gastric aspiration, near drowning, direct severe chest contusion, inhalation injury, sepsis, severe traumatic injury with shock requiring massive blood transfusions, acute pancreatitis, drug overdose What are the common early onset clinical symptoms of ARDS? - ANS within 48-72 hours, CXR shows mild alveolar infiltrates, increased respiratory distress, distress, tachypnea, dyspnea, respiratory alkalosis (s/t hyperventilation); PaO2 shows mild hypoxemia What are the common progressive clinical symptoms of ARDS? - ANS cyanosis, productive cough, diffuse crackles, tachycardia, accessory muscle use, increasing hypoxemia trends (refractory to oxygen therapy), increasing restriction on PFTs (decreasing compliance and FRC) What is essential to successful ARDS management? - ANS rapid identification and treatment of underlying cause of ARDS episode How should a nurse care for a patient in ARDS? - ANS assess and compare to established norms, baseline, and trends, decrease lung fluid, increase pulmonary gas exchange, maintain airway patency and protect airway, drug therapy, monitor for effects, maintain adequate O2 delivery, reduce metabolic needs, maintain nutritional balance, reduce anxiety and delirium, promote rest, promote communication and family support What is a major complication factor in ARDS & what can it cause? - ANS massive collapse of alveoli = significant shunt = decreased lung compliance = severe hypoxemia What does PEEP apply to? - ANS positive pressure into the patient's airway at the end of expiration and prevents alveoli from closing How does PEEP work? - ANS maintains alveoli in an open state through breathing cycle = increased gas diffusion time = increased gas exchange; reduces shunt by recruiting collapsed alveoli (popping them open) What is the goal in using PEEP? - ANS Achieve adequate PaO2 (60 mmHg), while reducing inspired FiO2 to less than 0.6; high O2 concentration can cause O2 toxicity What are a few complications of PEEP? - ANS decreased CO, overdistention of alveoli, pneumothorax, microatelectasis What are two types of therapy for patient positioning with ARDS? - ANS continuous lateral rotation therapy and prone positioning What causes a thromboembolism? - ANS venous stasis, hypercoagulability, venous (endothelial) injury What are some signs and symptoms of thromboembolism? - ANS tachypnea, dyspnea, pleuritic pain, apprehension, cough, fever, tachycardia, unilateral leg pain and swelling (DVT finding), hemoptysis, shock How is thromboembolism managed? - ANS O2 therapy, shock management, anticoagulant therapy (heparin, unfractionated heparin, low-molecular-weight heparin, fondaparinux, warfarin), vena cava filter, thrombolytic therapy, embolectomy What causes a fat embolism? - ANS when fat gains access to venous circulation; long-bone trauma or orthopedic surgery