Partial preview of the text
Download CCRN Cardiovascular Exam with Questions and Answers and more Exams Medicine in PDF only on Docsity!
A patient is in cardiac and respiratory arrest. The selection of medications to reestablish cardiac function would stimulate the sympathetic nervous system betal receptors. This stimulation would result in increased automaticity and which of the following? a. Increased myocardial contractility b. Decreased left ventricular stroke work c. Decreased myocardial oxygen consumption d, Increased left ventricular afterload ANSWERV ¥V Correct answer: a Rationale: The sympathetic nervous system contains alpha, beta, and dopaminergic receptors that produce various responses when stimulated. Stimulation of betal receptors increases heart rate, conductivity, and myocardial contractility. Stimulation of beta2 receptors produces vasodilation and bronchodilation. Alpha receptors, when stimulated, produce vasoconstriction. Stimulation of dopaminergic receptors produces a vasodilating effect on renal, mesenteric, coronary, and cerebral vessels. Test-Taking Strategy: Note the helpful clue in the stem: stimulate the sympathetic system and recall that this results in a fight-or-flight response—the body is responding to survive. Stroke volume would increase, so eliminate option b. Afterload would increase, but this is due to alpha stimulation, not beta! stimulation, so eliminate option d. Because the heart is working faster and harder, the myocardial oxygen consumption does increase, so eliminate option c. Remember that the primary effects of betal receptors are to increase heart rate, contractility, and rate of conduction. Choose option a. A memory aid that also may help is this: beta 1 beta 2, | heart 2 lungs: betal affects the heart, and beta? affects the lungs. A patient arrived in the emergency department with complaints of chest pain. The 12-lead elcctrocardiogram shows ST segment elevation in leads V3 and V4. Occlusion of the affected coronary artery most likely would affect perfusion to which portion of the conduction system? a. Sinoatrial (SA) node b. Bachmann's bundle c. Atrioventricular (AV) node d. Bundle of His ANSWERV V Correct answer: d Rationale: ST segment elevation in leads V3 and V4 indicates injury to the anterior wall, which would occur with ocelusi n of the left anterior descending (LAD) artery. In most persons, the SA node, Bachmann's bundle, and AV node are supplied by the right coronary artery. The bundle of Ilis is supplied by the left anterior descending artery. This is why an anterior myocardial infarction may cause type II second-degree AV block or third-degree AV heart block at the level of the bundle of His. Test-Taking Strategy: Note that options a, b, and ¢ are part of the supraventricular conduction system. They usually are supplicd by the right coronary artery. The LAD artery supplics most of the interventricular conduction system, including the bundle of His and the bundle branches. Oxygen delivery (DO2) is the product of which of the following? a. PaO2. hemoglobin, mean arterial pressure b. SaO2, hemoglobin, cardiac output c. SvO2, cardiac index, SaQ2 d, PaO2, mean arterial pressure, SVO2 ANSWERV ¥V Correct answer: b Rationale: Ninety-seven percent of oxygen is attached to the hemoglobin molecule, so the SaO2 (arterial oxygen saturation) is a more accurate reflection of the amount of oxygen in blood. The PaO2 represents only the 3% that is dissolved in the plasma. The lungs must put the oxygen in the blood, the hemoglobin must carry the oxygen, and the cardiac output is a reflection of how well the heart is moving the blood with its hemoglobin with attached oxygen. SvO2 (venous oxygen saturation) is a reflection of the oxygen reserve. SvO2 is what is left over after the tissues have extracted what they need. The mean arterial pressure is a c. Mural thrombi d. Decrease in ventricular filling ANSWERV V Correct answer: d Rationale: The contribution that atrial contraction makes to ventricular filling volume is approximately 15% to 30%. Atrial fibrillation results in quivering but not contracting atria. The loss of 15% to 30% of diastolic filling volume reduces cardiac output and can have significant hemodynamic consequences. Although mural thrombi also are a problem, they result in an embolic phenomenon rather than a direct decrease in cardiac output. The relationship between the development of atrial fibrillation and the decrease in cardiac output make hypovolemia and decrease in contractility less likely. Test-Taking Strategy: Relate recent changes in patient status to recent occurrences. The patient had a change in atrial function, so select an option that results in loss of atrial contraction or "kick." Choose option d. A shift in the point of maximal impulse (PMI) to the fifth left intercostal space at the anterior axillary line could be caused by any of these conditions except: a. left ventricular hypertrophy. b. right tension pneumothorax. ¢. pericardial effusion. d. right pleural effusion. ANSWERV ¥V Correct answer: ¢ Rationale: In pericardial cffusion or tamponade, there is frequently loss of palpability of the apical impulse because of the fluid layer. Left ventricular hypertrophy, right tension pneumothorax, and a right pleural effusion could shift the PMI left of normal. Normally the PMI is located at the fifth left intercostal space at the midclavicular line. Test-Taking Strategy: Look for the process that would not shift the PMI to the left of the normal position. Picture the process. If the left ventricle is big, it will extend farther to the left. If there is excessive pressure or volume on the right side, it will push the heart toward the left. Pericardial effusion will decrease the intensity of the PMI but it won't shift it. Choose option c. An S4 is an expected physical finding in which of the following? a. Acute myocardial infarction b. Left ventricular failure c. Pericarditis d. Bundle branch block ANSWERV V Correct answer: a Rationale: An S4 is an indication of ventricular noncompliance. Noncompliance is caused by ischemia, infarction, hypertrophy, cardiac tamponade, constrictive pericarditis, or restrictive cardiomyopathy. Left ventricular failure would cause an $3. Pericarditis would cause a pericardial friction rub. Bundle branch blocks cause splits (left bundle branch block causes a paradoxical split of S2, and right bundle branch block causes a split of S1 and increased splitting of $2 during inspiration). Test-Taking Strategy: Read the question carefully and note the key word expected. Associate $4 with a noncompliant ventricle. Ischemia, infarction, and hypertrophy cause noncompliance. Choose option a. A woman, age 35 years, reports the feeling that her heart is racing out of her chest. shortness of breath, and dizziness on admission to the critical care unit. The patient reports a history of a"floppy valve" for the past 10 years. Which of the following is truce regarding the murmur of mitral valve prolapse? a. Early systolic with a low-pitched, blowing quality b. Radiates to the carotid arteries c. Loudest at the lower left sternal border d. Usually accompanied by a midsystolic click ANSWERV V Correct answer: d Rationale: The murmur of mitral valve prolapse is caused by mitral regurgitation. Mitral regurgitation murmurs are high-pitched, blowing, systolic murmurs that are loudest at the apex and radiate to the axilla. When specific to mitral valve prolapse, a midsystolic click usually is heard at the apex, and the murmur follows the click such as $1, click, murmur, $2. Test-Taking Strategy: Remember that all murmurs are high-pitched with the exceptions of mitral stenosis and tricuspid stenosis, so eliminate option a. Radiation is in the direction of b. Calcium c. Sodium d. Magnesium ANSWERYV ¥ Correct answer: ¢ Rationale: Sodium affects phase 0 of the action potential or the cellular response to a stimulus that results in depolarization. A prolonged QT segment represents prolonged repolarization. Calcium, magnesium, or potassium imbalances may affect phases 2 and 3 of the action potential by shortening or lengthening this phase. Low levels of any of these would result in prolonged repolarization, which would be seen as a prolonged QT segment. Test-Taking Strategy: If you have no idea of the correct answer, use a common sense approach. Potassium, calcium, and magnesium abnormalities almost always are seen together. Also, abnormal levels are most likely to result in more severe abnormal body functions. Abnormal sodium levels are less likely to have as dramatic findings unless levels are extremely abnormal, as may be seen in endocrine abnormalities. Which of the following is a manifestation of left atrial enlargement on the electrocardiogram? a. Increased amplitude of the P wave on a rhythm strip b. Wide, notched P waves in lead II on 12-lead electrocardiogram c¢. Diphasic P wave in lead V1 on 12-Icad clectrocardiogram d. Tall, peaked P waves in lead II on 12-lead electrocardiogram ANS WERV ¥ Correct answer: b Rationale: P waves represent atrial contraction, so look for changes in the P waves as an indication of atrial enlargement. Leads II and V1 are the two best P wave leads. P waves ona voltage standardized 12-lead electrocardiogram should be about 2% blocks tall and 2% blocks wide. The P wave in lead II becomes tall and peaked in right atrial enlargement and wide and notched in lefi atrial enlargement. The P wave is normally diphasie in lead V1. The initial half of the normal diphasic P wave in lead V1 represents right atrial depolarization, and the terminal half of the normal diphasic P wave in lead V1 represents left atrial depolarization. Therefore right atrial enlargement causes a dominant initial half of the diphasic P wave in lead V1, whereas left atrial enlargement causes a dominant terminal half of the diphasic P wave in lead V1. Test-Taking Strategy: Rhythm strips have no standardization for voltage, and enlargement and hypertrophy are manifested by changes in voltage. So eliminate option a because anyone can increase the size of the P wave by increasing the size or gain. Diphasic P waves (ones that are positive and negative) are normal in lead V1, so climinate option c. Tall, peaked P waves in lead II are called P pulmonale and are associated with right atrial enlargement, so eliminate option d. Wide, notched P waves in lead II are called P mitrale and are associated with left atrial enlargement. Choose option b. A patient is admitted with unstable angina. He has a long history of hypertension and coronary artery disease. The nurse notes a split S2 on expiration and a single $2 on inspiration during cardiac auscultation. Blood pressure is 150/88 mm Hg, and heart rate is 88 beats/min. On the clectrocardiogram, there is a normal-appearing P wave in front of cach QRS complex, the PR interval measures 0.2 second consistently, and the QRS complexes measure 0.14 second. They are positive in V5 and V6 and negative in VI and V2. These findings most likely indicate which of the following? a. Left bundle branch block (LBBB) b. Right bundle branch block (RBBB) c. Third-degree atrioventricular block d. Ventricular tachycardia ANS WERV V Correct answer: a Rationale: Features of LBBB described here are a QRS complex greatcr than 0.12 second in duration and a QRS complex that is positive in leads V5 and V6 (consider these lefi ventricular leads) and negative in leads V1 and V2 (consider these right ventricular leads). LBBB causes a paradoxical splitting of S2. This means that it is split on expiration but not on inspiration. This is paradoxical because it is opposite of a normal physiologic split of S2, which is split on inspiration but not split on expiration. Test-Taking Strategy: A P wave precedes each QRS complex, so eliminate ventricular tachycardia, option d. A P wave occurs for each QRS complex, and the PR interval is consistent, so eliminate third-degree atrioventricular block, option c. The problem is a bundle branch block because it originates above the ventricle (note normal and consistent P waves), but the QRS complex is wide, indicating that the impulse is taking longer than normal to travel through the ventricle. Is the block left or right? Remember that the wide QRS complex Rationale: The PAd is normally 2 to 5 mm Hg higher than the PAOP. PAd may be more than 5 mm Hg higher than the PAOP in patients with pulmonary hypertension. If the PAOP is higher than the PAd, suspect that there is an occlusion in the catheter or that the catheter is not in the correct area of the pulmonary vasculature. The RAP is normally lower than the PAOP. Test-Taking Strategy: Remember that water does not flow uphill. The circuit between the pulmonary vascular bed and the left atrium is open. The pressure in the pulmonary artery during diastole is the filling pressure for the left atrium. So the PAd should be slightly higher than the PAOP. When pulmonary arterial diastolic pressure (PAd) is more than 5 mm Hg higher than pulmonary artery occlusive pressure (PAOP), it signals which abnormal condition? a. Right ventricular failure b. Left ventricular failure c. Pulmonary hypertension d. Systemic hypertension ANSWERV V Correct answer: ¢ Rationale: When the PAd is more than 5 mm Hg higher than the PAOP, it is an indication of pulmonary hypertension. Possible causes of pulmonary hypertension are passive (¢.g.. mitral valve disease) or active (¢.g., causes of hypoxemic pulmonary vasoconstriction such as acute respiratory distress syndrome, chronic obstructive pulmonary disease, or pulmonary embolism). Pulmonary embolism causes pulmonary hypertension by mechanical obstruction and by hypoxemic pulmonary vasoconstriction. Test-Taking Strategy: Consider the pulmonary artery systolic pressure as reflective of the right side of the heart, the PAd as reflective of the pulmonary vascular circuit, and the PAOP as reflective of the left side of the heart. Therefore the PAd would be reflective of a pulmonary vascular circuit problem. Left ventricular failure increases the PAd, but the PAOP is elevated also and there is not more than a S-mm Hg difference between the PAd and the PAOP. Right ventricular failure increases the RAP. Systemic hypertension increases systemic pressures. Which vasodilator would be best for a patient with a pulmonary artery occlusive pressure (PAOP) of 24 mm Hg and a systolic vascular resistance (SVR) of 2100 dynes/sec/em—5? a. Hydralazine (Apresoline) b. Nitroglycerin (Tridil) c. Nitroprusside (Nipride) d. Morphine sulfate ANS WERV V Correct answer: ¢ Rationale: Left ventricular preload (as measured by PAOP) and left ventricular afterload (as measured by SVR) are increased, so venous vasodilation is needed to decrease preload and arterial vasodilation is needed to decrease afterload. [lydralazine dilates arteries only, morphine sulfate dilates veins only, and nitroglycerin dosages must be above | meg/kg/min to achieve arterial dilating effects. Nitroprusside is a mixed vasodilator. It dilates arteries and veins to decrease afterload and preload. Test-Taking Strategy: Take this step by step. The PAOP indicates increased preload. The SVR indicated increased afterload. So both preload and afterload need to be decreased. Veins are pre-heart so dilating veins decreases preload. Arteries are after the heart so dilating arteries decreases afterload. Now which vasodilator dilates both arterics and veins? Of the choices here, nitroprusside is the best choice. A patient is admitted with acute chest pain and dyspnea. Pulse oximetry indicates an arterial oxygen saturation (SaO2) of 88%. Readings after insertion of the pulmonary artery catheter included a normal pulmonary artery occlusive pressure (PAOP), an clevated pulmonary artery, and an elevated right atrial pressure (RAP). The nurse suspects that these findings are most indicative of what acute problem? a. Cardiac tamponade b. Pulmonary embolism c. Right ventricular infarction d. Pericarditis ANS WERV V Correct answer: b normally close to 0. Any sudden decrease in the PA diastolic pressure should lead you to suspect that the catheter has flipped back into the right ventricle. Choose option a. At which point in the ventilatory cycle should the pulmonary artery occlusive pressure be measured? a. Alt the peak of inspiration b. At the end of expiration c. The average between inspiration and expiration d. Anytime in the ventilatory cycle ANSWERV ¥ Correct answer: b Rationale: [lemodynamic parameters should be measured at the end of expiration for consistency. If a patient is on a positive pressure volume-cycled mechanical ventilator, inspiration is the high point and expiration is the low or neutral point. If a patient is spontancously ventilating or is on a pressure-cycled mechanical ventilator, inspiration is negative and expiration is positive. Remember to identify where end expiration is: Patient or Pressure ventilation-Peak, Volume ventilator-Valley. Test-Taking Strategy: Consistency is the most important point here. Remember end expiration. Choose option b. While monitoring the patient's pulmonary artery pressure, a damped waveform is noted. Which of the following would not be an appropriate action? a. Ensure that the valve on the balloon lumen is open and that no air is trapped in the balloon. b. Reposition the patient. c. Fast flush the distal lumen. d. Check for a possible clot in the catheter by aspiration of the distal lumen. ANSWERV / Correct answer: c Rationale: A damped pulmonary artery waveform may be caused by air or blood in the pressure monitoring system, a clot in the catheter, or the catheter being advanced distally enough that the catheter diameter occludes the pulmonary arteriole in which the catheter is located (referred to as a spontaneous wedge). First, make sure that air has not been left in the balloon inadvertently by making sure that the balloon lumen is open with the empty syringe attached. Next, search the system for air or blood. ‘Then reposition the patient or ask the patient to cough. If there is no change in the waveform, try to aspirate a clot from the catheter. If there is still no change, have the paticnt assume a spontancous wedge position, and the catheter should be repositioned (withdrawn slightly) by the physician as soon as possible to prevent a pulmonary infarction. If the catheter is fast-flushed and a clot is present, it will be embolized with 300 mm Hg pressure (the pressure bag is maintained at this pressure). If the catheter is in a wedge position and the catheter is fast-flushed, it may result in pulmonary arteriole rupture and potentially massive hemoptysis and even exsanguination. Test-Taking Strategy: Remember that this is a negatively stated question. Answers a and b are benign and may help in some situations, so climinate them. Aspirating from the catheter does break the integrity of the closed circuit but is less dangerous than fast-flushing a catheter that may be occluded (increasing embolus risk) or spontaneously wedged (increasing hemorrhage risk). Option c represents a dangerous action and would not be appropriate. so it is the answer. All other answers are appropriate in this situation. Which of the following hemodynamic parameters is likely to be clevated with right ventricular infarction? a. Systolic pulmonary artery pressure (PAs) b. Pulmonary artery occlusive pressure (PAOP) c. Right atrial pressure (RAP) d. Diastolic pulmonary artery pressure (PAd) ANSWERV ¥ Correct answer: ¢ Rationale: RAP is elevated because of right ventricular failure and back pressure. PAs actually may be decreased because of the inability of the right ventricle effectively to propel blood into the pulmonary artery. PAd and PAOP usually are decreased as a reflection of poor filling caused by decreased right ventricular contractility. The filling of the left side of the heart (preload) is low because of the poor pumping ability of the right side of the heart. Remember that the right side of the heart sends blood to fill the left side of the heart. This is an example of backward failure of the right ventricle and forward failure of the left ventricle. Test-Taking Strategy: Right ventricular infarction frequently causes right ventricular failure. Remember that one of the major signs of right ventricular failure is jugular venous distention, heart are blocked by the inflated balloon. The only parameter among these three that relates to the left side of the heart is the PAOP. A 57-year-old man was admitted to the critical care unit with a diagnosis of anteroseptal myocardial infarction. A pulmonary artery catheter was inserted, and initial readings were within normal limits. Vital signs were blood pressure 140/92 mm Hg, heart rate 110 beats/min and regular, and respiratory rate 24 breaths/min. Breath sounds are equal and clear to auscultation. Three hours after admission, the patient becomes restless with cool, pale skin. Vital signs are now blood pressure 110/72 mm Hg, heart rate 120 beats/min, and respiratory rate 28 breaths/min and labored. Breath sounds are still equal, but crackles are audible at the lung bases bilaterally. Which medication would reduce this patient's preload most effectively? a. Nitroprusside (Nipride) b. Dopamine HC] (Intropin) c. Nitroglycerin (Tridil) d. Hydralazine HCI (Apresoline) ANSWERV V Correct answer: ¢ Rationale: Hydralazine HC] is an arterial dilator and would decrease afterload (remember arteries are after the heart). Nitroprusside is a mixed vasodilator with predominant arterial end effect. Nitroprusside would decrease afterload more than preload. Dopamine HCl is a vasoconstrictor in dosages greater than § meg/kg/min and ine! alicrload and possibly preload by decreasing the vascular capacitance. Nitroglycerin dilates predominantly veins (nitroglycerin dilates arteries only if the dosage is at least 1 mcg/kg/min [e.g., greater than 70 meg/min in a 70-kg patient]). By dilating veins and increasing venule capacitance, venous return to the heart and therefore preload are reduced (remember veins are before the heart). Test-Taking Strategy: Dopamine is an inotropic agent at doses of about 5 meg/kg/min and primarily a vasoconstrictor at higher doses, so eliminate option b. Iydralazine is an arterial vasodilator, and nitroprusside is a mixed vasodilator with predominantly arterial effects, so eliminate options d and a. Nitroglycerin is a predominantly venous vasodilator. Remember, veins are before (i.e., pre) the heart, and to decrease preload, you must dilate veins. Select option ¢. A 57-year-old man was admitted to the critical care unit with a diagnosis of anteroseptal myocardial infarction. A pulmonary artery catheter was inserted, and initial readings were within normal limits. Vital signs were blood pressure 140/92 mm Hg, heart rate 110 beats/min and regular, and respiratory rate 24 breaths/min. Breath sounds are cqual and clear to auscultation. Three hours after admission, the patient becomes restless with cool, pale skin. Vital signs are now blood pressure 110/72 mm Hg, heart rate 120 beats/min, and respiratory rate 28 breaths/min and labored. Breath sounds are still equal, but crackles are audible at the lung bases bilaterally. The patient is given furosemide (Lasix) at 8 AM. At 9 AM, the pulmonary artery occlusive pressure (PAOP) drops to 8 mm Hg with a drop in the blood pressure. Which of the following would be the most appropriate intervention at this time? a. Administer saline bolus. ANSWERV ¥ Correct answer: a Rationale: ‘Treatment of left ventricular failure requires manipulation of the determinants of stroke volume: preload, afterload, and contractility. Overdiuresis may result in an abnormal reduction of preload that leads to understretch of the myofibrils and decreased contractility. Tluid boluses often are given to restore adequate circulating blood volume and preload and to improve stroke volume and cardiac output. Venous vasodilators are titratable and are better agents than diuretics to reduce preload in a hemodynamically unstable patient. Note that even though a PAOP of 8 mm Hg is within "normal" values, a higher PAOP frequently is required for an optimal myofibril stretch, especially in patients with large ventricular diameter. Test-Taking Strategy: Furosemide decreases preload, and the hemodynamic changes occurred atter administration of this drug. Choose an option that would increase preload. Dobutamine increases contractility and decreases preload. Nitroglycerin decreases preload. Potassium would not have a direct effect. Saline bolus would increase preload, so choose option a. A 68-year-old man with a history of emphysema is scheduled for a colon resection. A pulmonary artery catheter is inserted before surgery and is to be used to guide fluid replacement during and after surgery. Postoperatively his vital signs are blood pressure 104/64 mm Ilg, heart rate 116 beats/min, and respiratory rate 32 breaths/min. Which of the following parameters would be most helpful in guiding fluid replacement for this patient? a. Mean arterial pressure (MAP) b. Pulmonary artery diastolic pressure (PAd) elevated but PAOP would be normal. Acute mitral regurgitation would cause large v waves but not large a waves. Test-Taking Strategy: Relate what is happening to what has happened. Cardiac surgery can cause option a, b, or c. Option d is much more likely in an acute myocardial infarction, so eliminate option d. Note the minimal mediastinal tube drainage. The expected mediastinal drainage is accumulating around the heart, so choose option ¢ by using a process of elimination based on what you know. What is the most frequently identified primary mechanism of cardiac arrest? a. Asystole b. Ventricular tachycardia c. Third-degree atrioventricular block d. Ventricular fibrillation ANSWERY ¥ Correct answer: d Rationale: Ventricular fibrillation is the most frequently identified primary mechanism of cardiac arrest. Test-Taking Strategy: The key word is primary. Cardiac arrest most likely is caused by irritability. Options b and d are examples of ventricular irritability. Ventricular tachycardia docs not always cause cardiac arrest, but ventricular fibrillation docs. Choose option d. A patient becomes apneic and pulseless. Cardiopulmonary resuscitation (CPR) has been initiated, and the monitor shows asystole in two leads. Which of the following drugs would be used initially? a. Calcium gluconate b. Atropine c. Epinephrine d. Amiodarone (Cordarone) ANS WERV ¥ Correct answer: ¢ Rationale: After CPR is initiated and an intravenous access is established, epinephrine should be given. Calcium was used in the past in asystole but is used today only for hypocalcemia, calcium channel blocker toxicity, hyperkalemia, and hypermagnesemia. Atropine is no longer recommended for asystole. Amiodarone is not indicated in asystole because asystole is the absolute absence of irritability. Test-Taking Strategy: Remember that in any pulseless situation, epinephrine is the number 1 drug. A patient arrives in the critical care unit with a diagnosis of acute myocardial infarction. An TV was established in the emergency department. The patient suddenly develops ventricular fibrillation. The s no femoral pulse. What is the priority action? a. Defibrillate with 200 J at once. b. Administer epinephrine. c. Initiate cardiopulmonary resuscitation (CPR). d. Administer amiodarone. ANSWER ¥ Correct answer: a Rationale: The longer the heart fibrillates, the less likely that defibrillation will be successful. The top priority in ventricular fibrillation is defibrillation. Initial voltage should be 200 J. CPR and epinephrine are indicated after defibrillation is unsuccessful. Amiodarone dosing is initiated after epinephrine. Test-Taking Strategy: Focus on treatment of cause. The patient's cardiac arrest is caused by ventricular fibrillation. Logical treatment would be defibrillation. Though CPR is important in maintaining minimal organ perfusion, it is simply a maintenance mechanism. CPR does not treat the cause of the cardiac arrest. Choose option a. In addition, remember that epinephrine is the number | drug in any pulscless situation, but it is not the number 1 treatment for ventricular fibrillation; defibrillation is. A 22-year-old patient is admitted to the critical care unit after a motorcycle collision. He has a fractured femur. Shortly after admission, he becomes pulseless, although the monitor shows. sinus tachycardia with a rate of 110 beats/min. Which of the following should be included in the patient's initial therapy? a. Intubation, mechanical ventilation, sodium bicarbonate