TEST #3 Perfusion II-kahoots/ATI
Normal Digoxin range
0.8-2.0
What is the normal range for Magnesium?
1.5-2.5 mEq/L
How much fluid does the pericardial sac hold?
10-15 mL
Normal Hemoglobin range
12-18g/dl
Normal PR rate
120-200
What is the normal range for sodium?
135-145 mEq/L
When does rheumatic fever show up?
2-3 weeks after untreated strep
Biological valves require an anticoagulant for how long?
3 months
Hold Digoxin if K+ is lower than:
3.5
What is the normal range for potassium?
3.5-5.0 mEq/L
What should the nurse assess with arterial ischemic disorder?
6 Ps -pain -pallor -pulselessness -paralysis -parasthesia (pins & needles) -poikilothermia
How many new cases of heart failure are diagnosed each year?
6.5 million
Hold Digoxin if apical HR is less than:
60
Normal calcium range
8.6-10.3
What is the normal range for Chloride?
95-105 mEq/L
A nurse is caring for a client who has an abdominal aortic aneurysm and is scheduled for surgery. The client's vital signs are BP: 160/98, HR 102, RR 22, O2 95%. Which action should the nurse take first? A. Administer antihypertensive medication for blood pressure. B. Monitor that urinary output is 20 mL/hr. C. Withhold pain medication to prepare for surgery. D. Take vital signs every 2 hr.
A. Administer antihypertensive medication for blood pressure. The nurse should administer antihypertensive medication for the elevated blood pressure because hypertension can cause a sudden rupture of the aneurysm due to pressure on the arterial wall.
A nurse is caring for a client who had an MI 5 days ago. Pt has a sudden onset of SOB and begins coughing frothy, pink sputum. Upon auscultation, bubbly sounds on inspiration. Which adventitious breath sounds should the nurse document? A. Coarse crackles B. Wheezes C. Rhonchi D. Friction rub
A. Coarse crackles A client who had a recent myocardial infarction is at risk for left-sided heart failure. Crackles are breath sounds caused by movement of air through airways partially or intermittently occluded with fluid and are associated with heart failure and frothy sputum. Crackling sounds are heard at the end of inspiration and are not cleared by coughing.
A nurse is assessing a client who has a fluid volume overload from a cardiovascular disorder. Which manifestations should the nurse expect? (select all) A.Jugular vein distension B. Moist crackles C. Postural hypotension D. Increased heart rate E. Fever
A. Jugular vein distension is correct. The increase in venous pressure due to excessive circulating blood volume results in neck vein distension. B. Moist crackles is correct. This is an indicator of pulmonary edema that can quickly lead to death. D. Increased heart rate is correct. Fluid volume excess, or hypervolemia, is an expansion of fluid volume in the extracellular fluid compartment. This results in increased heart rate and bounding pulses.
A nurse is reviewing the history of a patient who is about to begin furosemide (lasix) therapy to treat HTN. Which of these drugs that the pt takes should alert the nurse to take further action? A. Lithium (Lithobid) for bipolar disorder B. Phenytoin (Dilantin) for a seizure disorder C. Erythromycin (Erythrocin) for bronchitis D. Warfarin (Coumadin) to prevent blood clots
A. Lithium (Lithobid) for bipolar disorder Furosemide, a high-ceiling loop diuretic, increases sodium loss and can cause reabsorption of lithium, a mood stabilizer. This puts patients taking both drugs at increased risk for lithium toxicity.
A nurse is completing a medical history for a client who reports using fish oil as a dietary supplement. Which substance in fish oil is a health benefit to the client? A. Omega-3 fatty acids B. Antioxidants C. Vitamins A, D, and C D. Beta-carotene
A. Omega-3 fatty acids Fish oil contains omega-3 fatty acids, which can help lower the risk of cardiovascular disease and stroke by decreasing triglyceride levels.
A nurse is caring for a pt who is postoperative following vein ligation and stripping for varicose veins. Which action should the nurse take? A. Position the client supine with his legs elevated when in bed. B. Encourage the client to ambulate for 15 min every hour while awake for the first 24 hr. C. Tell the client to sit with his legs dependent after ambulating. D. Instruct the client to wear knee-length socks for 2 weeks after surgery.
A. Position the client supine with his legs elevated when in bed. The nurse should elevate the client's legs above his heart to promote venous return by gravity. During discharge teaching, the nurse should reinforce the importance of periodic positioning of the legs above the heart.
A nurse is caring for a pt who has HF and who telemetry reading displays flattening of the T wave. Which lab result should the nurse anticipate as the cause of this ECG change? A. Potassium 2.8 mEq/L B. Digoxin level 0.7 ng/mL C. Hemoglobin 9.8 g/dL D. Calcium 8.0 mg
A. Potassium 2.8 mEq/L A flattened T wave or the development of U waves is indicative of a low potassium level.
A nurse is caring for a pt who is about to begin captopril therapy to treat HTN. When talking with the pt about taking the drug, the nurse should tell her to report which of these adverse effects because they could indicate a need to stop the drug. (select all) A. Rash B. Distorted taste C. Swelling of the tongue D. Photosensitivity E. Dry cough
A. Rash is correct. Captopril, an ACE inhibitor, can cause a persistent rash. This often indicates the need to stop drug therapy. B. Distorted taste is correct. Captopril can cause distortions in taste sensations, often salty or metallic, which can lead to anorexia and weight loss. This often indicates the need to stop drug therapy. C. Swelling of the tongue is correct. Captopril can cause angioedema, often manifesting as edema of the tongue, pharynx, and glottis. Patients who develop this adverse effect should stop taking the drug and seek medical attention. E. Dry cough is correct. Captopril can cause a dry cough because of an accumulation of bradykinin. This often indicates the need to stop drug therapy.
What is used if a chronic HF patient can't tolerate ACE Inhibitors?
ARBs (no cough associated)
Peripheral artery disease will have how much drainage?
Almost none
A nurse is providing teaching about lifestyle changes to a client who had an MI and has a new prescription for a beta blocker. Which statement indicates understanding? A. "I should eat foods high in saturated fat." B. "Before taking my medication, I will count my radial pulse rate." C. "I will exercise once per week for an hour at the health club." D. "I will stop taking my medication when my blood pressure is within a normal range."
B. "Before taking my medication, I will count my radial pulse rate." A beta blocker will induce bradycardia. The client should take her pulse rate for 1 min before self-administration.
A nurse on a telemetry unit is caring for a client who has an irregular radial pulse. Which ECG abnormalities should the nurse recognize as atrial flutter? A. P waves occurring at 0.16 seconds before each QRS complex B. Atrial rate of 300/min with QRS complex of 80/min C. Ventricular rate of 82/min with an atrial rate of 80/min D. An irregular ventricular rate of 125/min with a wide QRS pattern
B. Atrial rate of 300/min with QRS complex of 80/min The nurse should interpret this finding as atrial flutter, which indicates a lack of conduction between the atria and ventricles. The additional atrial beats are not conducting.
A nurse is caring for a pt about to begin taking Ethacrynic Acid to treat HF. The nurse should tell the pt to report which indications of a potentially serious adverse reaction? A. Shortness of breath B. Hearing loss C. Swelling in the legs D.Blurred vision
B. Hearing loss Ethacrynic acid, a high-ceiling loop diuretic similar in actions and effects to furosemide (Lasix), can cause ototoxicity, which can lead to permanent hearing loss. While hearing loss is transient with furosemide, it is sometimes permanent with ethacrynic acid.
When talking with a pt about taking Clonidine for HTN, the nurse should explain that discontinuing the drug abruptly can result in which of these adverse effects? A. Constipation B. Hypertension C. Drowsiness D. Dry mouth
B. Hypertension Abruptly discontinuing clonidine, a centrally acting alpha2 agonist, can cause rebound hypertension. The drug's target receptors are in the CNS. By stimulating these receptors, sympathetic outflow to the peripheral blood vessels decreases. Thus, the blood vessels dilate and the heart rate slows. Stopping drug therapy causes rebound outflow from the sympathetic nervous system and a sudden and significant rise in blood pressure that can lead to a hypertensive crisis.
A nurse is monitoring a client who has HF due to mitral stenosis. The client reports SOB on exertion. Which condition should the nurse expect? A. Increased cardiac output B. Increased pulmonary congestion C. Decreased left atria pressure D. Decreased pulmonary artery pressure
B. Increased pulmonary congestion Pulmonary congestion occurs due to right-sided heart failure. Because of the defect in the mitral valve, the left atrial pressure rises, the left atrium dilates, there is an increase in pulmonary artery pressure, and hypertrophy of the right ventricle occurs. In this case, dyspnea is an indication of pulmonary congestion and right-sided heart failure.
A nurse is caring for a pt who is about to start taking simvastatin to treat hyperchlosterolemia. The nurse should tell the pt to report which indications of a serious adverse reaction that could warrant stopping drug therapy? A. Bronchoconstriction B. Muscle pain C. Lip numbness D. Somnolence
B. Muscle pain Simvastatin, an HMG-CoA reductase inhibitor (statin), can cause myopathy or pain in muscles and joints that can progress to rhabdomyolysis. With this rare but serious adverse effect, muscle protein breaks down and its excretion causes kidney damage.
A provider is considering the various drug therapy options for treating a patient's cardiac dysrhythmia. He should be aware that which of the following antidysrhythmic drugs is appropriate only for short-term use because of its severe adverse effects with long-term use? A. Quinidine B. Procainamide C. Nitroglycerin D. Verapamil (Calan)
B. Procainamide Procainamide, a sodium channel blocker and a broad-spectrum antidysrhythmic, is a poor choice for long-term control of dysrhythmias because of its risk for serious adverse effects, including cardiotoxicity and arterial embolism.
A nurse is administering a unit of packed red blood cells to a post-op client. Client reports itching and has hives 30 minutes after the infusion begins. Which action should be taken first? A. Maintain the IV access with 0.9% sodium chloride. B. Stop the infusion of blood. C. Send the blood container and tubing to the blood bank. D. Obtain a urine sample.
B. Stop the infusion of blood. The nurse should apply the urgent vs. nonurgent priority-setting framework. Using this framework, the nurse should consider urgent needs the priority because they pose more of a threat to the client. The nurse might also need to use Maslow's hierarchy of needs, the ABC priority-setting framework, or nursing knowledge to identify which finding is the most urgent. The nurse should stop the infusion of blood because the client has manifestations of an allergic reaction.
A nurse is caring for a pt taking Spirolactone for HPTN. Which lab value should alert the nurse to take further action? A.Serum sodium level of 140 mEq/L B.Serum potassium level of 5.2 mEq/L C.Serum chloride level of 100 mEq/L D.Serum magnesium level of 1.9 mEq/L
B.Serum potassium level of 5.2 mEq/L Spironolactone, a diuretic and an aldosterone antagonist, can cause hyperkalemia and put patients at risk for cardiac dysrhythmias. This level exceeds the expected reference range of 3.5 to 5.0 mEq/L and warrants immediate intervention.
A nurse in a clinic is assessing the lower extremities and ankles of a client with history of peripheral arterial disease. Which finding should the nurse expect? A.Pitting edema B. Areas of reddish-brown pigmentation C. Dry, pale skin with minimal body hair D. Sunburned appearance with desquamation
C. Dry, pale skin with minimal body hair A client who has peripheral arterial disease can display dry, scaly, pale, or mottled skin with minimal body hair because of narrowing of the arteries in the legs and feet. This causes a decrease in blood flow to the distal extremities, which can lead to tissue damage. Common manifestations are intermittent claudication (leg pain with exercise), cold or numb feet at rest, loss of hair on the lower legs, and weakened pulses.
A pt taking Digoxin develops ECG changes & other manifestations indicating sever Digoxin toxicity. Which drug should the nurse have available to treat this complication? A. Acetylcysteine (Acetadote) B. Flumazenil (Mazicon) C. Fab antibody fragments (Digibind) D. Deferoxamine (Desferal)
C. Fab antibody fragments (Digibind) Fab antibody fragments, also called digoxin immune Fab, binds to digoxin and blocks its action. The health care professional should prepare to administer this antidote IV to patients who have severe digoxin toxicity.
A nurse is caring for a pt who is about to begin taking propanolol to treat a tachydysrhythmia. The nurse should caution the pt about taking which OTC drug? A. Antihistamines B. Potassium supplements C. NSAIDs D. Vitamin C
C. NSAIDs NSAIDs can interact with propranolol and decrease the anti-hypertensive action because in some COX-2 inhibitors vasoconstriction can occur. The nurse should instruct the patient to avoid taking NSAIDs and propranolol at the same time.
A nurse is assessing a patient following the adminastreation of nifedipine. Recoginzing the adverse effects of nifedipine, the health care professional should be prepared to administer which drug? A. Prazosin (Minipress) B. Doxazosin (Cardura) C. Propranolol (Inderal) D. Enalapril (Vasotec)
C. Propranolol (Inderal) Nifedipine, a calcium channel blocker, can cause reflex tachycardia, an adverse effect that increases cardiac oxygen demand. Administering a beta-adrenergic blocker, such as propranolol, will minimize this adverse effect.
A nurse is monitoring a client who had an MI. For which complication should the nurse monitor within the first 24 hrs? A. Infective endocarditis B. Pericarditis C. Ventricular dysrhythmias D. Pulmonary emboli
C. Ventricular dysrhythmias After a myocardial infarction, the electrical conduction system of the heart can be irritable and prone to dysrhythmias. Ischemic tissue caused by the infarction can also interfere with the normal conduction patterns of the heart's electrical system.
First thing you do with asystole after patient has been assessed and is pulseless:
CPR- this is not a chockable rhythm
Biological valves can be from what animal?
Cow, pig, shark one time
Signs of Left heart failure
D- ysnea (difficultly breathing) R- ails O- rthopnea (discomfort laying flat) W- eakness N- octuria (waking up in the night to urinate) I- ncreased HR N- agging cough (pink foam-late sign) G- ain weight
A nurse is caring for a client who is in hypovolemic shock. While waiting for a unit of blood, the nurse should administer which IV solution? A. 0.45% sodium chloride B. Dextrose 5% in 0.9% sodium chloride C. Dextrose 10% in water D. 0.9% sodium chloride
D. 0.9% sodium chloride Solutions of 0.9% sodium chloride, as well as Lactated Ringer's solution, are used for fluid volume replacement. Sodium chloride, a crystalloid, is a physiologic isotonic solution that replaces lost volume in the blood stream and is the only solution to use when infusing blood products.
A nurse is about to administer atenolol to a pt who has HPTN. Which assessment should the nurse perform prior to giving the patient the drug? A. Respiratory rate B. Level of consciousness C. Serum glucose D. Apical pulse
D. Apical pulse Atenolol, a beta1 adrenergic blocking agent, can cause bradycardia and orthostatic hypotension. Health care professionals should withhold the drug for an apical heart rate slower than 60/min and notify the primary care provider.
A nurse is completing an assessment for a client with history of unstable angina. Which finding should the nurse expect? A. Chest pain is relieved soon after resting. B. Nitroglycerin relieves chest pain. C. Physical exertion does not precipitate chest pain. D. Chest pain lasts longer than 15 min.
D. Chest pain lasts longer than 15 min. The client who has unstable angina will have chest pain lasting longer than 15 min. This is due to the reduced blood flow in a coronary artery due to atherosclerotic plaque and thrombus formation causing partial arterial obstruction, or from an artery spasm.
Pt takes carvedilol for HTN is about to begin taking an oral antidiabetes drug to manage newly diagnosed Type 2 DM. Nurse should make sure the PCP knows the pt is at increased risk for which of the following if she takes both drugs? A. Hyperglycemia B. Bradycardia C. Hypotension D.Hypoglycemia
D. Hypoglycemia Two factors increase the patient's risk for hypoglycemia. Alpha/beta blockers, such as carvedilol, potentiate the hypoglycemic effects of insulin and oral hypoglycemic drugs. Also, carvedilol can mask tachycardia in a patient who has hypoglycemia. Using carvedilol with patients who have diabetes mellitus requires caution.
A nurse is caring for a pt who is about to begin taking Verapamil to treat atrial fibrillation. The nurse should tell the pt to avoid grapefruit juice while taking this because it can cause: A. tachycardia. B. dehydration. C. diarrhea. D. hypotension.
D. hypotension. Large amounts of grapefruit juice increase blood levels of verapamil by inhibiting its metabolism. The excess amount of drug can intensify otherwise therapeutic effects like hypotension, causing serious risks for syncope and dizziness.
S/S of aortic stenosis
Dyspnea Angina syncope on exertion Rt heart failure late in disease
When administering Digoxin what other medications need to be monitored?
HCTZ (diuretic) -releases K+
What are the late signs of mycarditis?
HF, crackles, angina
What are some of the primary risk factors for heart failure?
HTN, CAD, MI, Cardiomyopathy
What does mycarditis result in?
Heart dysfunctions
What treats heart failure?
Morphine (vasodialates & lowers anxiety), Nitro (chest pain), Furosemide (loop diaretic, flood retention)
Can an LPN interpret an EKG strip?
NO
Why do you need to tell your dentist if you have a biological valve?
Need to be on AB before a procedure
Signs of R heart failure
S- welling W- eight gain E- dema -pitting L- are distended neck vein (JVD) L- ethargic I- rregular HR N- octuria G- irth -abdomen swelling
What are the only two EKG results you would defibrilate?
Ventricular Tachycardia and Ventricular Fibrilation
What blood tests should be done for pericarditis?
WBC (increased infection), cardiac enzymes
Diagnostic studies for endocarditis?
WBC, blood cultures, X-ray
Can an LPN delegate asprin 81 mg PR?
YES
What is regurgitation?
a backward flow of blood as the valve doesn't close properly
What is the most caused vascular disorder due to rhumatic fever?
aortic stenosis
QRS --> ORS amount of time:
less than .10 seconds (10 milliseconds)
A patient with a mechanical valve needs to be on __________ anti-coagulation therapy
longterm
Key nursing management with pericarditis
manage pain and anxiety
Buerger's disease labs and diagnostics?
none
Priorty nursing care formycarditis includes these 2 things:
oxygen and ventilation
What is nursing management for mycarditis?
oxygen therapy, bedrest or restricted activity, Lanoxin (for HR reduction)
What is the hallmark sign of pericarditis?
pericardial friction rub
What disease has shiny, taut and cool skin?
peripheral artery disease
Signs and symptoms of endocarditis:
roth's spots, chills, murmurs (new or worsening)
Tachycardia first step:
treat underlying cause (fever, sepsis)
First step when a patient is in Asystole?
assess the patient (check pulse)
How do you treat atrial fibrilation?
blood thinners, beta blockers, antiarrhythmics
First nursing action with Venticular Tachycardia?
check pulse
What is stenosis?
constriction or narrowing (valves can't completely open or close)
How do you treat an asymptomatic patient?
continue to monitor
P waves measure:
depolarization of the atrium
QRS measures:
depolarization of ventricles
2nd step to determine an EKG strip?
determine rate
1st step to determine an EKG strip?
determine rhythm -regular or irregular
Diagnostic studies of valve disorders?
echo (valve structure), cardiac cath (detect pressure changes), CT (aortic VD)
What is the inner most layer of the heart?
endocardium
What are the early signs of mycarditis?
fever, fatigue, throat hurts, dysnea
A patient with peripheral artery disease experiences intermittent claudication, what is the nursing intervention?
have patient rest for 10 mins or so
How do you treat a normal sinus rhythm with 2 PVSs?
if it doesn't self correct, beta blockers
With peripheral artery disease peripheral pulses:
will be decreased or absent
A nurse is caring for a client who has a demand pacemaker inserted with the rate set at 72/min. Which finding should the nurse expect? A. Telemetry monitoring shows QRS complexes occurring at a rate of 74/min with no pacing spikes. B. The client is experiencing premature ventricular complexes at 12/min. C. Telemetry monitoring shows pacing spikes with no QRS complexes. D. The client is experiencing hiccups.
A. Telemetry monitoring shows QRS complexes occurring at a rate of 74/min with no pacing spikes The nurse should not expect pacer spikes when the client's pulse is greater than the set rate of 72/min, because the client's intrinsic rate overrides the set rate of the pacemaker.
A nurse is assessing a client who has late stage HF and experience fluid overload syndrome. Which finding should the nurse expect? A. Weight gain 1 kg (2.2 lb) in 1 day B. Pitting edema +1 C. Client report of nocturnal cough D. B-Type Natriuretic Peptide (BNP) level of 100 pg/mL
A. Weight gain 1 kg (2.2 lb) in 1 day A weight gain of 1 kg (2.2 lb) in 1 day alerts the nurse that the client is retaining fluid and is at risk of fluid volume overload. This is an indication that the client's heart failure is worsening.
A health care professional caring for pt about to start Losartan for HPTN. Nurse should tell pt to report what indicatoin of adverse reactions: A.Facial edema B.Sleepiness C.Peripheral edema D.Constipation
A. facial edema Losartan, an angiotensin II receptor blocker, can cause angioedema, often manifesting as redness and swelling around the eyes and lips. Patients who develop this adverse effect should stop taking the drug and seek medical attention
When a blood culture and AB are both orderd, which do you do first and why?
AB if you give them after the culture, it will change the results
How do you treat rheumatic fever?
AB therapy
"I need to avoid exposure of the limb to the cold" is a statement that would be made by a patient with what disease?
Buerger's Disease
Nurse is caring for pt who is about to start using transdermal nitroglycerin for angina pectoris. Which instructions for use should be given? (select all) A. Apply a new patch at the onset of anginal pain. B. Apply the patch to dry skin and cover the area with plastic wrap. C. Apply the patch to a hairless area and rotate sites. D. Apply a new patch each morning. E. Remove patches for 10 to 12 hr daily.
C. .Apply the patch to a hairless area and rotate sites is correct. Hair can interfere with the adhesion of the patch. Rotating sites helps prevent skin irritation. D. Apply a new patch each morning is correct. Therapeutic preventive effects of transdermal nitroglycerin patches begin 30 to 60 min after application and last up to 14 hr. Because angina pain is more likely with activity, most patients require this protection during waking hours. E. Remove patches for 10 to 12 hr daily is correct. Removing the patches for 10 to 12 hr each day helps prevent tolerance to the drug. For most patients, sleeping hours are the best time to go "patch-free," as angina pain is more likely during activity.
A nurse is caring for a pt who has moderate to severe HTN and is about to begin hydralazine therapy. The nurse should monitor the pt for which adverse reaction to the drug? A. A flu-like syndrome B. Extrapyramidal symptoms C. A lupus-like syndrome D. Hypertensive crisis
C. A lupus-like syndrome A systemic lupus erythematosus-like syndrome can develop with hydralazine, a direct-acting vasodilator. Manifestations include facial rash, joint pain, fever, nephritis, and pericarditis. High doses make it more likely. Fluid retention and edema can also develop.
A nurse is assessing for cardiac tamponade on a client who had coronary artery bypass grafts. Which action should the nurse take? A. Check for hypertension. B. Auscultate for loud, bounding heart sounds. C. Auscultate blood pressure for pulsus paradoxus. D. Check for a pulse deficit.
C. Auscultate blood pressure for pulsus paradoxus. The client who has cardiac tamponade will have pulsus paradoxus when the systolic blood pressure is at least 10 mm Hg higher on expiration than on inspiration. This occurs because of the sudden decrease in cardiac output from the fluid compressing the atria and ventricles.
Pt is taking Eplernone for HTN. Nurse should include what instruction? A. Avoid drinking grapefruit juice. B. Use sunscreen and protective clothing. C. Avoid the use of salt substitutes. D. Stop taking the drug if dizziness occurs.
C. Avoid the use of salt substitutes. Eplerenone, an aldosterone antagonist, can cause hyperkalemia. Many salt substitutes contain significant amounts of potassium. Patients who take the drug should not use salt substitutes that contain potassium.
A nurse is assessing a client who has pericarditis. Which manifestation should the nurse expect? A.Bradycardia with S-T segment depression B. Relief of chest pain with deep inspiration C. Dyspnea with hiccups D. Chest pain that increases when sitting upright
C. Dyspnea with hiccups The client who has pericarditis will experience dyspnea, hiccups, and a nonproductive cough. These manifestations can indicate heart failure from pericardial compression due to constrictive pericarditis or cardiac tamponade.
A nurse is assessing a client who has right-sided heart failure. Which of the following findings should the nurse expect? A. Decreased capillary refill B. Dyspnea C. Orthopnea D. Dependent edema
D. Dependent edema Blood return from the venous system to the right atrium is impaired by a weakened right heart. The subsequent systemic venous backup leads to development of dependent edema.
A nurse is assessing a client who has an abdominal aortic aneurysm. Which manifestation should be expected? A. Midsternal chest pain B. Thrill C. Pitting edema in lower extremities D. Lower back discomfort
D. Lower back discomfort Abdominal aortic aneurysm involves a widening, stretching, or ballooning of the aorta. Back and abdominal pain indicate that the aneurysm is extending downward and pressing on lumbar spinal nerve roots, causing pain.
