324-Exam 1 (Cardiac, Electrolytes, Acid Base, Hematology, PeriOp)

Osmolarity vs Osmolality

Osmolality and osmolarity both measure the concentration of solute particles in a solution, but differ in their unit of measurement. Osmolality measures osmoles of solute per kilogram of solvent (mOsm/kg, temperature-independent), while osmolarity measures osmoles per liter of solution (mOsm/L, temperature-dependent).

Key Differences:

Definition: Osmolality is based on weight (kg), while Osmolarity is based on volume (L).

Isotonic Solution

0.9% saline

Hypertonic Solution

3 or 5% saline or partenteral solutions

Hypotonic Solution

0.45% Saline

Insensible Water Loss

Fluid loss that cannot be measured (Respiration, sweat, tears, weeping, wounds, stool)

Sodium Range

135-145 mmol/L

Hyponatremia range and Causes

<135 mEq/L, Critical Value <120

Causes: Diuretics (esp Furosemide), NPO, low-salt, excessive ingestion of hypotonic fluids (Ex. >18L of tap water per day)

What are the cerebral assessment signs of hyponatremia?

Sudden confusion, change in behavior, change in level of consciousness (LOC)

What are the neuromuscular assessment signs of hyponatremia?

Muscle weakness; check respiratory effectiveness

What are the intestinal assessment signs of hyponatremia?

Increased motility

What are the cardiovascular assessment signs of hyponatremia?

Severe orthostatic hypotension, decreased blood pressure, rapid weak thready pulse

Hyponatremia Interventions

-Tolvaptan (Drug that causes hypernatremia, salt based)

-Reduce dose of drugs that increase sodium loss

-IV saline infusion

Hyponatremia Correction Max

Correction of hyponatremia should never exceed max rate of 8 mEq/L in any 24hr period

Hypernatremia Range and Causes

Range >145

Causes: NPO, fever, dehydration, excess intake, IV hypertonic

What are the neurological signs of hypernatremia?

Altered mental status, agitation, confusion, short attension span

What are the neuromuscular signs of hypernatremia?

Muscle twitching, irregular muscle contraction, reduced or absent deep tendon reflex

What are the cardiovascular signs of hypernatremia?

Increased pulse rate, hypotension

Hypernatremia Interventions

Prevent dehydration and hyponatremia. NS or dextrose 5% in 0.45% NaCl. Adequate water intake and avoid processed foods

Potassium Range

3.5-5.0 mEq/L

Hypokalemia Range and Causes

<3.5 mEq/L

Causes: Diuretics (furosemide), diarrhea/vomit, prolonged NG suction, water intoxication, NPO, heat induced sweating

What are the cardiovascualr assessment findings of hypokalemia?

Weak/thready pulse, ECG change, irregular pulse, hypotension

What are the neuromuscualr assessment findings of hypokalemia?

Muscle weakness, altered mental status

What are the respiratory assessement findings of hypokalemia?

Shallow respirations, increased effort, increased rate and depth, alkalosis

Hypokalemia Interventions

Priority= Adequate gas exchange, prevents fall, monitor response

PO/IV Potassium Chloride (stop immediately if potassium infiltrates the interstitial space)

What is the ECG change of hypokalemia?

Shallow T-wave, presence of a U wave

Hyperkalemia Range and Causes

>5.0

Causes: Salt substitutes, potassium (PO or IV), blood transfusion, tissue damage, K+ sparing diuretics, uncontrolled diabetes, ACE/ARBS

What is an example of a potassium sparing diuretic that can cause hyperkalemia?

Spironolactone

What are the neuromuscular assessement findings of hyperkalemia?

Skeletal muscle twitch, tingling/burning, parasthesia

What are the cardiovascular assessment findings of hyperkalemia?

Bradycardia, hypotension, ECG changes, Vfib

What are the GI assessment findings of hyperkalemia?

Increased motility (diarrhea), hyperactive bowel tones

Hypokalemia Drug Interventions

Patriomer (poop out K+), Insulin (given with 50% dextrose), potassium wasting diuretics (Furosemide)

What is the ECG change of hyperkalemia?

Peaked T waves, wide QRS, and loss of P wave. (In order from least severe to most severe)

Calcium Range

9.0-10.5 mg/Dl

Requries active form of Vit D to be absorbed. Think muscle/heart!

Hypocalemia Range and Causes

<9.0 mg/dL

Causes: Inadequate oral intake of calcium, Vit D or Diarrhea

Result: Bone resorption (osteoclasts)

Hypocalcemia Signs/Cues

Muscle spasms, thyroid surgery, parasthesia of hands and feet, tingling, loss of bone density, height changes, chrons or celiacd disease, prolonged QT/ST

Positive Chvostek's sign

A sign of hypocalcemia. Tapping on facial nerve stimulates facial twitching.

Positive Trousseau's sign

A sign of hypocalcemia. BP cuff inflated to create hypoxic condition on arm, hand and finger will go into spasm

Hypocalcemia Interventions

Calcium/Vit D supplementation

Reduce environment stimuli

Prevent injuries (weak bones)

Hypercalcemia Range and Causes

>10.5 mg/dL

Causes: Excessive oral intake (ex. TUMS), use of thiazide diuretics, immobility, dehydration, glucocorticoids

What are the CV assessment findings of hypercalcemia?

Increased HR, Increased BP (acute), slow HR (chronic), poor perfusion, ECG changes

What are the NM assessment findings of hypercalemia?

Severe muscle weakness, decreaed deep tendon reflexes, confusion, lethargy

What are the GI assessment findings of hypercalcemia?

Constipation, nausea, vomiting, ab distension, hypoactive bowel tones

Hypercalcemia Interventions

Prevent calcium resoprtion with phosphorus, calcitonin, and bishosphonates

NS, discontinue supplementation

Magnesium Range

1.6-2.2 mg/dL

Hypomagnesmia Range and Causes

<1.6, Critical <1.2

Causes: Malnutrition, starvation, diarrhea, alcohol use disoder, loop or thiazide diuretics

Hypomagemesmia Cardiovascular Assessment Findings

Arrhythmia, QT and PR prolongation, hypertension

Hypomagnemesia NM Assessment Findings

Tetany (involuntary spasms/cramps)

Hypomagnemesia GI Assessment Findings

Anorexia, nausea, paralytic ileus

Hypomagnemesia Interventions

Restore normal calcium levels, IV magnesium, discontinue: loop diuretics, aminoglycoside, antibiotics

Hypermagnesmia

>2.2, Critical >4.0

think lethargy

Hypermagnesmia CV Assessment Findings

Bradycardia, peripheral vasodilaton, hypotension, ECG changes

Hypermagnesmia NM Assessment Findings

Weakness, respiratory depression, decreased mental function, dowsy, fatigue. Not usually apparent symptoms until critical

Hypermagnesmia Interventions

Reduce serum level, Mg2+ free IV fluids, loop diuretics, Calcium (if cardiac problems)

What are cardiovascular cues of fluid overload?

Hypertension, bounding pulse, tachycardia, JVD, S3 heart sound

What are respiratory cues of fluid overload?

Crackles, shortness of breath (SOB), orthopnea, pulmonary edema (PE), decreased O2

What are peripheral cues of fluid overload?

Edema, rapid weight gain, tight shiny skin

What are neurologic cues of fluid overload?

Headache, confusion, restlessness

What laboratory findings are associated with fluid overload?

Decreased hemoglobin, decreased hematocrit, hyponatremia

Dehydration Assessment Findings

Increased HR, decreased BP, concentrated urine (specific gravity >1.030), elevated hemoglobin, hematocrit, serum osmolarity, etc.

Hemoconcentration

An increase in the concentration of red blood cells, hemoglobin, and hematocrit, generally caused by a reduction in plasma volume

Human Arterial Blood pH Range

7.35-7.45

Fatal pH Ranges

>6.9 or >7.8

What are pH buffers?

Compounds that help keep the pH from changing drastically by soaking up or releasing H+ ions.

What are some examples of pH buffers?

Phosphate, proteins, albumin, globulins, hemoglobin.

What is the first line of defense for pH regulation?

pH buffers.

What is the second line of defense for pH regulation?

The respiratory system. (Quick)

What is the third line of defense for pH regulation?

The kidneys. (Slow but effective, 24-48hrs)

Greatest risk for acidosis

Patients with breaht problems (COPD, asthma) and chronic health conditions

Causes of metabolic acidosis

Diabetes/DKA, shock, diarrhea, renal failure, liver disease, sepsis, use of aspirin (salicyates), CO poisoning

Biggest concern of acidosis

Cardiovascular problems due to risk for hyperkalemia

(Too much H+ kicks K+ out of cells)

Common cause of Metabolic Alkalosis

Vomiting or NG suctioning (losing stomach acid). Also, excessive intake of antacids, durietic use, hypovolemia

Relative Alkalosis

No increase in base, acid decreases

Alkalosis Outcomes

Hypokalemia (K+ leaves cell to resotre balance of no H+), increased CNS activity, irritability, seizures, positive chvostek sign/trosseus sign

What two electrolyte imbalances are often seen with alkalosis?

Low potassium and low calcium often go together

What precautions should an alkalotic patient be put on?

Seizure precautions

polydipsia

Excessive thirt, and ingestions of fluid (>3L/day). Could be related to SIAHD, DI or psychiatric

BNP

Hormone produced by heart in response to stretching, an indicator of heart failure

Oliguria

Low urine output, less than 400 ml/day or <20-30mL/hr

Anuria

absence of urine production

Polyuria

excessive production of urine (>2.5-3L/day)

Dysuria

painful or difficult urination, often associated with a UTI

Nocturia

frequent urination at night

Cardiac Output

Amount of blood pumped by the heart every minute

Stroke Volume

Volume of blood pumped out of left ventricle during each contraction

HR x SV = Cardiac Output

Stroke Volume= Preload-Afterload

Preload (Stretch)

Amount of blood in left ventricle after filling (pre-ejection)

Afterload (Squeeze)

Pressure your heart has to pump against to eject the blood from the left ventricle (Goal=low)

What does the term cardiomyopathy refer to?

It describes all diseases of the heart muscle.

What effect does too much preload have on the heart?

It can overstretch the heart.

What is the impact of too much hypertension on the heart?

It increases afterload pressure, making the heart work harder.

Mean Arterial Pressure

Force (pressure) being exerted against vessel walls at any given point OR the average arterial pressure during a single cardiac cycle

Cardiac Cycle

The complete, rhythmic sequence of electrical and mechanical events in the heart, lasting about 0.8 seconds (at 75 bpm) from the start of one heartbeat to the next. It consists of systole (contraction/ejection) and diastole (relaxation/filling)

3 P's of Perfusion

Pump (heart), Pipes (blood vessels), Plasma (blood)

Conductivity of cardiac cells

The ability of all cardiac muscle cells to transmit electrical impulses, effected by levels of K+, Ca+, Mg, Na

Automaticity of Cardiac cells

The cells ability to spontaneously depolarize (generate electrical impulse) without external nerve stimulation

Excitiability of Cardiac Cells

The ability of cells to generate electrical signs to trigger coordinated contractions

Contractility of Cardiac Cells

ability to respond mechanically to an impulse. Intrinsically generate force and pump blood

Intrinsic Cardiac Pace Maker

SA Node (60-100 BPM), shown by P wave

AV Node Rate

Produce impulses from 40-60bpm

Bundle of His and Purkinje fibers Rate

20-40 bpm

P wave indicates what?

atrial depolarization (contraction)