MedSurg 1 Exam 1 Review W1-2

Review of Week 1-6 Content

Body Fluids

Intracellular Fluid (ICF)

• Fluid within the cell, accounts for 2/3 of body fluid

Extracellular Fluid (ECF)

• Fluid outside the cell, accounting for 1/3 of body fluid, further divided into three main sub compartments

  • Intravascular fluid: fluid within the blood vessels, aka plasma

  • Interstitial fluid: fluid between cells, tissues, organs, and blood vessels

  • Transcellular fluid: specialized fluids enclosed by epithelial membranes (CSF, pericardial, synovial, intraocular, pleural)

Hypervolemia and Hypovolemia Causes

Deficit/Hypovolemia

• GI Losses (Vomiting/Diarrhea)

• Overuse of diuretics

• Inadequate fluid intake

• Burns

• Surgery

• Medication

Excess/Hypervolemia

• Heart failure

• Renal failure

• Excess fluid intake

• Medication induced

Hypervolemia and Hypovolemia Signs and Symptoms

Hypovolemia

• Restlessness, lethargy, thirst, dry mucous membranes, decreased skin turgor, weight loss

Hypervolemia

• Edema, JVD, dyspnea/crackles, weight gain, increased BP

IV Solutions

• Isotonic fluids - fluid remains in intravascular space no net fluid shift (0.9NS, LR, D5W)

• Hypertonic fluids - more concentrated fluids, draw water from cell into intravascular space causing cells to shrink (3NS, 5NS)

• Hypotonic fluids - less concentrated fluids, draw water from intravascular space into cell causing cells to swell (0.45NS)

0.9 Sodium Chloride

• Isotonic solution also known as normal saline, containing only sodium and chloride

• Only IV solution given with blood products

• Indicated for patients with dehydration from vomiting, diarrhea, sweating

• Use cautiously in patients with fluid volume overload as will exacerbate issue

Lactated Ringers

• Isotonic solution

• Contains sodium, chloride, potassium, calcium, and lactate

• Indicated for patients with burns, trauma surgery, and GI losses

• Contraindicated in patients with kidney failure, liver failure, or lactic acidosis

D5W

• 5% dextrose in water

• First isotonic but as dextrose metabolized hypotonic

• Indicated for patients with hypernatremia, fluid loss, and dehydration

• Contraindicated in patients with

  • Head injury - cerebral edema

  • Fluid resuscitation - hyperglycemia

0.45 Sodium Chloride

• Hypotonic solution

• Used to treat hypernatremia, uncontrolled hyperglycemia, gastric fluid loss,

• Contraindicated in third spacing fluid shifts or increased intercranial pressure

Specialty IV Solutions

• Total Parental Nutrition TPN - highly concentrated formulation used to give nutrition when GI tract cannot be used

  • requires central line, high infection risk

  • monitor blood glucose levels

• Colloid Solutions - volume expanders that pull fluid into bloodstream

  • examples albumin, FFP, blood products

  • risk of fluid overload

Sodium

• Function: blood volume and blood pressure regulation

• Imbalances think brain and fluid volume status

• Most dominant electrolyte in extracellular fluid

Hyponatremia

• Causes - sodium loss/hypovolemic, excess water gain/hypervolemic

• ***aldosterone retains Na and water, excretes K+

• Manifestations

  • neurologic - HA, confusion, altered LOC, lethargy, seizures

  • fluid status cues, s/s dehydration/over hydration dependent on cause

• MOA - low sodium - fluid shift to cells - brain cells swelling

• Management

  • sodium replacement - oral, NS, LR

  • severe cases 3% hypertonic saline with monitoring

Hypernatremia

• Causes - inadequate water intake, excess water loss, excess sodium intake , DI, Cushing Syndrome

• Manifestations

  • neurologic - restlessness, agitation, confusion, lethargy, hyperreflexia, seizures, coma

  • s/s dehydration

• MOA - high sodium - fluid shift out of cells - brain cells shrink

• Management

  • 1st restore volume/hydrate intravascularly with isotonic IV fluids

  • 2nd administer hypotonic to move fluid to cells

Potassium

• Function

  • manage heart and muscle function (K+ = electrical stability)

  • maintain fluid balance and BP

  • regulated by kidneys

• Most dominant electrolyte in intracellular fluid

• Kalemias do the same as the prefix except for HR and urine output

Hypokalemia

• Causes - increased output, decreased intake

• Manifestations

  • *** life threatening decreased neuromuscular excitability

  • cardiac - dysrhythmias (flattened/inverted T waves, ST depression, prominent U waves)

  • neuro - lethargy, irritability, AMS, coma

  • musc - weakness, decreased deep tendon reflexes

  • resp - shallow respirations, respiratory musc weakness

  • gi - decreased bowel motility, constipation, abd distention

• Management - Potassium Replacement Therapy

  • NEVER give IV bolus at risk of cardiac arrest/death

  • before giving verify last serum K, assess renal function, and confirm urine output (no pee no K)

Hyperkalemia

• Causes - impaired renal excretion, excess intake, cell injuries, adrenal insufficiency, meds

• Manifestations

  • ***increased neuromuscular excitability

  • cardiac - dysrhythmias (PEAKED T WAVES, widened QRS, bradycardia, cardiac arrest)

  • neuromusc - fatigue, irritability, confusion, muscle weakness/paralysis

  • gi - increased motility, diarrhea, hyperactive bowel

• Management

  • Protect heart with IV Calcium Gluconate

  • Monitor ECG

  • Shift K In - insulin + dextrose, sodium bicarb

  • Remove K - kayexalate, furosemide, hemodialysis

Calcium

• Function

  • stabilize neuron excitability

  • control 3Bs: bones, blood, beats

  • regulated by parathyroid hormone and calcitonin

  • inverse relationship with phosphorous

• Calcemias do the opposite of the prefix

Hypocalcemia

• Causes - low intake, low parathyroid hormone, calcium loss/binding (renal failure, blood transfusion, laxative abuse/diarrhea)

• Manifestations - increased neuromuscular excitability

  • neuromusc - seizures, tetany (numbness/tingling, twitching, Chvostek and Trousseau signs)

  • cardiovasc - QT prolongation, bleeding risk

  • gi - hyperactive bowel sounds, abd cramping

  • skeletal - decreased bone density, height loss, spinal curvature

Hypercalcemia

• Causes - hyperparathyroidism, malignant cancer cells, excess calcium or vitamin d intake, osteoporosis, prolonged immobility, thiazide diuretics

• Manifestations - decreased neuromuscular excitability

  • neuromusc - fatigue, musc weakness, decreased DTRs, confusion

  • cardiovasc - decreased HR, hypertension, ECg changes, shortened QT

  • gi - n/v, constipation, distention, anorexia

• Management -

  • hydration

  • eliminate calcium - furosemide, calcitonin, bisphosphonates, dialysis

  • monitor cardiac

Magnesium

• Function: neuromuscular relaxation

• Second most abundant intracellular cation after potassium

• Excreted by kidneys

Hypomagnesemia

• Causes - poor intake, GI losses, renal losses (treatment of DKA insulin shifts mg into cell)

• Manifestations - increased neuromuscular excitability

  • neuromusc - seizures, hyperactive DTRs, tremors, paresthesias, confusion/irritability

  • cardiovascular - dysrhythmias, QT prolongation, inverted T waves, Torsade de Pointes

• Management

  • replace mag with PO magnesium oxide or IV magnesium sulfate (NEVER give as IV bolus can cause heart block, hypotension, and cardiac arrest)

  • cardiac monitoring

  • prevent injury

Hypermagnesemia

• Causes - too much magnesium, not enough magnesium out

• Manifestations - neuromuscular relaxation

  • neuromusc - lethargy/drowsiness, dec DTRs, musc weakness, urinary retention, respiratory depression

  • cardiovasc - hypotension, vasodilation/flushing, ecg changes, prolonged pr interval, widened qrs

• Management

  • Monitor cardiac, respirations, DTRs

  • Remove magnesium with fluids or hemodialysis

  • Reverse and prevent cardiac harm through IV Calcium Gluconate

Properties of Heart Cells

Electrical Properties

• Automaticity - ability to initiate and maintain electrical rhythm

• Excitability - ability to respond to the electrical stimulus

• Conductivity - ability to transfer that electrical stimulus to the neighboring cell

Mechanical Properties

• Contractility - ability of myocardial cells to shorten and contract in response to an electrical stimulus

Cardiac Conduction System

• SA Node - primary pacemaker, initiates electrical impulses, inherent rate 60-100

• AV Node - synchronizes atrial and ventricle activity, assumes electrical impulse if SA node fails at inherent rate of 40-60

• Bundle of His - located between atria and ventricles, should be only conduction pathway, other pathways indicate conduction issues

• Left and Right Bundle Branch

• Purkinje Fibers - ventricles are stimulated to contract, assumes pacemaker if SA and AV fail at inherent rate of 30-40

12-Lead ECG vs Continuous Monitoring

12 Lead ECG

• uses 10 electrodes (one on each limb 6 on chest) to produce 12 different waveforms showing a frontal and transverse view of heart

• Traces electrical activity between positive and negative points

• Electrode placement must be accurate and consistent

Continuous Monitoring

• 5 leads RA, LA, RL, LL, V1

P wave

• Atrial depolarization/ atrial contraction

• Normal wave round, upright symmetrical <0.12 sec

PR Interval

• Measured from beginning of P wave to beginning of QRS complex, represents the time for impulse to travel from SA node through AV node

• Normal PR 0.12 - 0.20

QRS Complex

• Ventricular depolarization/ventricular contraction

• Consists of three waveforms:

  • Q Wave - negative deflection after P Wave

  • R Wave - positive deflection after P Wave

  • S Wave - first negative deflection after R wave

• Normal ARS nice neat narrow, 0.04 - 0.10 seconds, measured to J-point

• J-point - junction point, physical spot on ECG tracing where the QRS complex ends and the ST segment begins, compared to isoelectric line

T Wave

• Represents ventricular repolarization (recovery) or the relative refractory period

• Rounded, usually upright

U Wave

• Through to represent repolarization of Purkinje Fibers, may or not be present (may be present in hypokalemia, hypertension, and heart disease)

ST Segment

• Early ventricular repolarization, shows the brief pause after the ventricles have fully contracted and stay contracted to push blood out to lungs and body

• End of QRS/J-point to beginning of T Wave

• ST Segment elevation - J-point is above isoelectric line represents injury

  • injury - damage to cardiac muscle

• ST Segment Depression - J-point is below isoelectric line represents ischemia

  • ischemia - lack of oxygen to cardiac muscle

• Both can lead to cardiac necrosis which is dead, irreversible damage to cardiac muscle, TIME IS TISSUE

QT Interval

• Total time for ventricular depolarization and repolarization

• Measured from beginning of QRS to the end of the T wave

• Lethal is QT interval becomes prolonged (longer than 0.35-0.45) as delayed electrical recovery can trigger torsades de pointes which can go to vfib and arrest

Lethal Arrythmias

• Ventricular Fibrillation - stops heart from pumping any meaningful amounts of blood

• Ventricular Tachycardia - too little time for heart to fill between beats, can degrade to V-fib

• Asystole - complete absence of electrical and mechanical activity in heart, aka flatline with no contractions or blood flow

Normal Sinus Rhythm

• Rate 60-100BPM

• Regular Rhythm

• Normal P wave, PR interval, and QRS duration

Arrhythmias/Dysthymias

• Disorders of the electrical impulse within the heart that cause disturbances

• Named according to site of origin of impulse and the mechanism of conduction

Sinus Brady

• Rate < 60BPM

• Regular Rhythm

• Normal P wave, PR interval, and QRS duration

• Causes - lower metabolic needs, medication induced, vagal stimulation, increased ICP, inferior wall MI

• If due to shock can give Atropine - drug of choice

Sinus Tachy

• Rate > 100 BPM

• Regular Rhythm

• Normal P wave, PR interval, QRS duration

• Cause - psychologic or physiologic stress, meds, stimulants, illicit drugs

Atrial Flutter

• Rate

  • Atrial 200-300 BPM

  • Ventricular 75-150 BPM

• Regular Rhythm

• Flutter P wave, not measurable PR interval, normal QRS duration

• Causes - CAD, HTN, Hyperthyroidism, Tricuspid Valve Disease

• Management -

  • cardioversion if unstable, sink shock on QRS

  • anticoagulants, risk for blood clot

  • beta blockers

Atrial Fibrillation

• Criteria - no discernible P wave, ventricular rhythm is irregularly irregular

• Rate

  • Atrial 300-400

  • Ventricular rapid, variable

• Irregular Rhythm

• P wave not identifiable, PR not measurable, normal QRS duration

• MANY CAUSES

• Management

  • main goal rate and rhythm control

    • rate bblockers, ccblockers, digozxin

    • rhythm - synchronized cardioversion, pharmacologic cardioversion AMIODARONE

  • anticoagulation

Premature Ventricular Complex (PVCs)

• Rate - depends on underlying rhythm

• Regular Rhythm

• P wave may be absent, normal PR interval, QRS duration abnormal >0.12 wide/bizarre

• Patterns

  • bigeminy - every other complex premature

  • couplet - two sequential complexes

  • run - three or more successive PVCS AKA VTACH

  • multifocal - PVCs that differ in size, shape, and direction

  • R on T Phenomenon - PVC occurring on or near T wave, no rest ventricles won’t fill and puts patients in a lethal rhythm

Pacemakers

• Electronic device that delivers electrical stimulation to the heart to regulate the heart rate, may be temporary or permanent

• Used for bradyarrhythmias, heart blocks, and some tachyarrhythmias

• Different than AICD (automatic internal cardiac defibrillator)

• Can be

  • Atrial pacing - pacer spike happens immediately before P wave

  • Ventricular pacing - pacer spike happens immediately before QRS wave

• Pacemaker Fails on ECG

  • Failure to sense - pacer fails to sense patient’s own intrinsic beat and fires causing competition problems

  • Failure to capture - pacer spike occurs but no depolarization of muscle detected with QRS complex