Electrolytes: Fluids Flashcards
Hypokalemia= k< ____, symptomatic often below _____
3.5
3.0
Hypokalemia causes
Redistribution from ECF to ICF
Decreased intake
Total K deficit
Hypo K; Redistribution of K from ECF to ICF caused by….
(Some of these are also tx for hyperkalemia)
Alkalosis
Insulin
Beta 2 agonists
Hypercalcemia
Hypomagnesemia
Things to AVOID in Hypokalemia, due to further K depletion in ECF…
Glucose solutions
Hyperventilating (alkalosis)
Rapid correction of acidosis
When replacing K, we should also check and replace ____
Mag
No need to correct chronic Hypokalemia with K < 2.5 mEq/L prior to induction unless _____ therapy
Digitalis
k replacement recommendations for dosage
Less than or equal to 10 mEq/hour
PO Is safest
Hypokalemia effects on NMB drugs?
Hypo k causes weakness- weakness augments NMB
Hypokalemia effects on EKG
Decreased contractility
Hyper-polarized cell (increased gradient)
Flattened t waves
U waves
Increased PRI
Increased QT
atrial of ventricular arrhythmias
Hyperkalemia defined as k > _____, must treat K > ______
Most danger K > ______
5.5
6
7
S/s of acute hyperkalemia
Muscle weakness, especially in legs and respiratory system
Paresthesias (neuro)
Hyperkalemia conduction changes
Prolonged PRI
Peaked T
Loss of P wave
Wide QRS
Vfib/arrest
Etiology Of hyper K
Decreased excretion
ICF to ECF shift
Artificial elevation due to hemolysis of blood sample (double check)
Hypoaldosteronism (aldosterone holds Na and excretes K)
Potassium sparing diuretics (spirolactone)
If your Co2 increases 10 mmhg, the pH will ______ by _____, and the plasma K will increase by ______ mEq/L
Decrease by 0.1
0.5
pH and plasma K are ________ proportional
Inversely proportional
Caution with these medications in renal failure patients
NSAIDS
ACEI
CSA (cyclosporine A)
Administration of succinylcholine is dangerous due to this effect;
Caution in patients with _______
Opens all K pumps and rapidly moves K from intra to extra cellular space, can cause V fib and cardiac arrest
Caution in hyperkalemic patients
If you must use succinylcholine, this may have a protective effect
Hyperventilating prior to injection
Hyperkalemic patients, take precautions to avoid _______ when managing breathing
Hypoventilation, due to increase Co2x decreasing pH, driving more K to ECF
Considering cancelling elective surgery if K>_____.
Do consider if it is acute or chronic. Chronic failure chronic elevation may tolerate
5.5
Always treat K > _____
6
Avoid what induction med in hyperkalemia?
Succinylcholine
Steps to treat hyperkalemia that is life threatening (ekg changes, greater than 6.5, high risk patient)
1) stabilize the heart with Ca (CaCl or calcium gluconate). Consider repeating if EKG changes persist
2) shift K into cells- regular insulin (10-20 units) and glucose (25-50 g)
3) beta 2 agonist inhaled- shift K into cells
4) enhance elimination of K- considering patients volume status-
-low volume- resus with .9 nacl then use loop diuretic it UOP is present
-high volume- move straight to diuretic if UOP is present
No UOP? Dialysis
NMDMR consideration with hyper K?
skeletal weakness suggests decreased dose for muscle relaxants intraop- titrate to effect
IV fluid considerations for hyperkalemia
If using large doses of fluid/ make sure no K.
LR, K is low, but without elimination can build in high doses
Magnesium controls ______ reabsorption in renal tubules
k
______ stabilizes membranes, influences releases of neurotransmitters at the NMJ.
Can inhibit entry of Ca into presynaptic nerve terminals
Endogenous Ca antagonist
Magnesium
This electrolyte is an endogenous NMDA receptor antagonist
Magnesium
Blocks N-methyl receptor, similar to ketamine?
Essential co factor to many enzymatic reactions; DNA and protein synthesis, energy metabolism, glucose utilization, FFA synthesis
Magnesium
Hypomagnesemia= mag < ____ mEq/L
1.5
Hypomagnesemia caused by….
Inadequate intake
Protracted vomiting, diarrhea
Renal insufficiency
Hypomagnesemia signs and symptoms
Skeletal muscle spasms and weakness
CNS irritability
Seizures, hyper-reflexia, confusion, ataxia, cardiac irritability
Hypomagnesemia tx
MgSO4 bolus- 1 go over 15-20 mins
Rate no greater than 1 mEq/min
Hypomagnesemia anesthetic consideration;
Look for associated disturbances; Hypokalemia, hyponatremia, hypocalcemia
Frequently occurs in alcoholic patients
Hypermagnesemia = mag > _____ mEqs/L
2.5
Hypermagnesemia associated with….
Acute or chronic renal failure
Toxemia from magnesium therapy
Overadmin if magnesium containing compounds (ie antacids, cathartics)
Hypermagnesemia s/s
Skeletal muscle weakness
Can lead to respiratory arrest
Vasodilation, hypotension
Myocardial depression, hypotension
Complete heart block
Hyporeflexia, diminished DTR
sedation
Hypermagnesemia tx….
Stop mag therapy/intake- (often infused in OB)
Increase excretion (loop diuretic)
Antagonize CV or NM toxicity with CaCl or Ca gluconate (transient effect, gives time to excrete mag)
Anesthetic considerations in Hypermagnesemia
Magnesium potentials the action of NDMR- NMB will last LONGER
Intubation for pt if respiratory reflexes become compromised (OB)
What type of calcium is measured (physiologically active) for our purposes
Ionized calcium
Calcium is found primarily in ____ and then _____ fluid
Bone
ECF
___- _____ % of calcium is protein bound to albumin in the plasma
40-45
Calcium is regulated by these two hormones—
And what endocrine organ!
Calcitonin
Parathyroid hormone
Parathyroid glands
_______ is essential for all movement, all normal excitation-contraction coupling of myocardial and skeletal muscle
Calcium
_________ is the neurotransmitter released into the synaptic gap
Calcium
______ causes the plateau phase of cardiac muscle cells
Calcium
Hypocalcemia-
Serum ca < ____ mg/dl
Ionized Ca< ____ mEq/L
8.5
2
Hypocalcemia etiologies;
Malabsorption
Increased excretion due to renal insufficiency
Hypoparathyroidism
Chelation from citrate in blood transfusions (transient, negligible unless renal/hepatic failure or hypothermia)
Shift into cell with alkalosis IE acute resp alkalosis (increased mV, this is the reason hyperventilation of anxiety can cause parasthesias of the lips)
Hypocalcemia: s/s
CNS; parasthesias (especially circumpolar) confusion, seizures
CV; decrease myocardial contractility, hypotension, cardiac failure, arrhythmias. Negative inotropy- decreased camp, decreased cardiac AP
NM; twitching, cramping, trousseaus sign, chevosteks sign, convulsions, laryngospasm
Major airway consideration/caution with hypocalcemia
Laryngospasms
Hypocalcemia/ effect on EKG
Prolonged QTC
Anesthetic considerations for hypocalcemia-
Replace calcium, evaluate pt history, renal function, serum phosphate (inversely proportional)
Avoid alkalosis- drives Ca into cells
Monitor Ionized calcium
Monitor patient with replacement
Calcium replacements;
CaCl; 3-5 ml of 10%
13.6 mEq per gram
CaGluc; 10-20 ml of 10%
4.65 mEq per gram
Caution treating Hypokalemia without correction of _______ ; may precipitate tetany
Calcium
Calcium replacement may antagonize what medication
CCB
Hypercalcemia=
Ca> ____ mg/dl
Ionized ca > ____ mEqs/L
8.5
2.25
Causes of Hypercalcemia
Decreased renal excretion secondary to hyperparathyroidism
Immobility (causing shift from bones to cells)
Bone malignancies
Increased intake (antacids, vitamin D)
Hypercalcemia s/s
Muscle weakness
CNS depression
Nephrolithiasis
Increased sensitive to digoxin
HTN
Prolonged PR, WIDE QRS
Hypercalcemia tx;
Hydration with NS plus lasix to inhibit renal reabsorption and promote Ca excretion
Dialysis
Chelators (phosphate, EDTA)
Biphosphonates (inhibit bone breakdown, slow onset, long duration ) used on osteoporosis and bone malignancies
Calcitonin (fast onset, short duration) used with biphosphates
Hypercalcemia anesthetic considerations;
IV Phosphate use is faster- but oral is safer
LOWER doses of NDMR if skeletal muscle weakness
Invasive monitoring with decreased cardiac function
Acute acidosis increases ionized Ca
Caution with EDTA; significant hypocalcemia can result
When waking someone up; with muscle weakness secondary to electrolyte imbalance _______ may be impaired
Respiratory function;
May not be able to breathe on their own
Anion gap equation.
AG= (Na+K) - (HCo3+Cl)
Normal anion gap
10 +- 2 mEqs/L
An anion gap means that there is ________ amount of charged ions that are not included in a metabolic panel. This is suggestive of ______ _______ such as DKA, lactic acidosis.
Unmeasured
Organic acidosis
Normal anion gap in a patient with metabolic acidosis indicates ________, commonly from renal or GI bicarb losses such as renal tubular acidosis or diarrhea
Hyperchloremic acidosis
Most common electrolyte disturbance in hospitalized patients 
Hyponatremia
Hyponatremia is commonly due to an excess in ______ , for example in instances of SIADH
Total body water
The blood brain barrier is poorly permeable to sodium but very permeable to water therefore a rapid decrease in sodium will cause _______
Brain and water swelling, cerebral edema 
Hyponatremia S/S
Arterial hypertension
Increased CVP
Pulmonary edema
Decreased cardiac function
Arrhythmias
Malaise
Headache
Lethargy
Seizures/coma
Hyponatremia = sodium < ____
GA safe is Na plasma >_____
135
130
Anesthetic implications for hyponatremia?
Can you manage the underlying cause?
Can sx be postponed? Symptoms and urgency.
Principal extra cellular cation
Na
Essential for Action potentials in neuro in cardiac tissue
Na
Correction of hyponatremia,
“ too fast too soon versus too slow too late”
Equation; 
0.6 X (Wt in Kg) X (desired sodium-actual sodium) = total amount of milliequivalents needed to replace deficit
Half is replaced in the first eight hours the remainder over 24 to 72 hours if signs and symptoms resolve
Recommended solution for treating non-emergent hypo natremia
0.9 Normal saline with loop diuretic (free water excess) and monitor of sodium levels
Recommendation for sodium increase
Non-emergent?
Emergent?
Non emergent;
< 1-2 mEqs/hour
< or equal to 8 mEq per day
Emergent; Raise slowly to approximately 120 to 1 25 mEq per liter, by max 10-20 mEq/L in 24 hrs
Emergent hyponatremia correction solution; (emergent due to complications including CNS/neuro and cardiac)
3% NS bolus, monitor Na levels
Risk of fast of hyponatremia
Pontine demyelination
Surgery specific considerations regarding hyponatremia and transurethral resection of the prostate
Hypotonic irrigation fluid during resection moves across prostate into venous sinuses and plasma resulting in increase in total body water and decrease in sodium
If possible use neuraxial block to keep patient awake and monitor for neurological changes use isotonic solution to replace fluid and blood loss
Hypernatremia can be ________ or relative to _____ , meaning due to dehydration.
Absolute
TBW
plasma sodium greater ____ than causes water loss from cells and crenation
145
__________ Is common in geriatric patients due to decreased thirst and loss of ability to concentrate urine
Hypernatremia
Hyponatremia signs and symptoms—
Tremors
weakness
irritability,confusion
seizures, coma
hypovolemia
renal insufficiency
diabetes insipidus
Hypovolemic hypernatremia is due ______ loss to exceeding ______ loss
Water loss
Sodium loss
Hypovolemic hypernatremia; etiologies
Diarrhea
vomiting
osmotic diuresis
inadequate intake
fever
burns
exposed surgical areas
prolong positive pressure ventilation without humidity
Symptoms of hypovolemic hypernatremia
Hypotension
decrease CVP
decreased urine output
decreased skin turgor
increased heart rate
Fluid replacement recommendations for hyponatremic hypovolemia
If hemodynamically unstable replace with a .45 or .9 Saline, Then calculate Freewater deficit and replace with D5W or hypotonic fluids
Hypervolemic hypernatremia is due to Na overload….
Name a few causes-
Dialysis with hypertonic solution
treatment with hypertonic saline
bicarb administration
Symptoms of hypervolemic hypernatremia
Increase weight
increase blood pressure
Edema
CHF
Rales
Treatment for hypervolemic hypernatremia
Excess sodium removed by dialysis or diuretics
Water deficit replaced by D5W
Caution using LR with what conditions?
Metabolic or respiratory alkalosis
Hepatic or renal failure
Is LR compatible with blood products?
No- has calcium
LR is not a good maintenance fluid due to…
Low k 4
Low na 130
Normal saline compared with plasma regarding pH osmolarity and chloride
Low pH 
High osmolarity
high chloride
Excessive administration of normal saline (greater than 2 to 3 L) can cause what?
Hyperchloremic metabolic acidosis
This can take days to resolve in patients with renal insufficiency or failure
Risks associated with hypertonic saline use (3%)
Overshoot of sodium to hypernatremia- (pontine demyelination)
Hyperchloremia
Cellular dehydration and crenation
When using hypertonic saline (ie for tx of cerebral edema) ; goals to achieve plasma sodium of _____- _____, and increased no more than _____ mEqs per 24 hours. 
145-155
10-20
Uses for hypertonic saline;
Severe symptomatic hyponatremia
Fluid resuscitation
Increased ICP
D5W is considered ____tonic 
Hypotonic
PH of normal saline (0.9)
Sodium of normal saline
Chloride of normal saline
5.6
154
154
Equation for hourly maintence requirements
4-2-1 rule…. first 10 kg multiplied by four ML‘s per KG per hour, Next 10 kg multiplied by two in miles per KG per hour. Remaining kilograms multiplied by one hour per KG per hour
How much fluid do you add to plan for bowel prep
1 L Replace upfront
NPO replacement equation
Hours NPO times hourly maintenance requirement by the 421 rule. replace over the first 2 to 3 hours of surgery
Minimal moderate and severe third space losses based on potential tissue trauma
Minimal ______
Moderate _____
Severe _____
0-2 ml/kg/hr
2-4 ml/kg/hr
4-8 ml/kg/hr
True surgical loss replacement with Crystalloid and colloid, Proportional recommendations
Crystalloid 3 to 1
Colloid 1 to 1
An open surgery would be considered what type of potential or evaporated of Thirdspace loss?
Severe 4-8 ml/kg/hr
Equation for Estimated blood volume
EBV= TYPICAL blood volume X pt wt in kg
Estimated blood volume an adult male
75 ml/kg
Estimator blood volume an adult female
70 ml/kg
Estimated blood volume in a school age child
75 ml/kg
Estimated blood volume in a child one to 12 months old
80 ml/kg
Estimated blood volume in a neonate
85 ml/kg
Equation for allowable blood loss
ABL= (EBV* (Hct initial-Hct final))/ Hct initial
Hct of 24 is approximately Hgb of 8
This equation In practice tells you when to draw blood and check your hemoglobin
What is the fluid recommendation in a lung resection?
Minimize fluids and use pressers if necessary due to post pneumonectomy pulmonary edema complications
Avoid use of blood products due to inflammatory response
Consideration regarding fluid in liver failure or transplant
Use colloids, Consider use of Colloid replacement early
Multiple comorbidities confound food management including cerebral edema hepatorenal syndrome and electrolyte disturbances
Replace paracentesis of greater ____ than liters with _____
4 L
Albumin 1:1
Burn patient formula a.k.a. Parkland formula
BSA BURNED X WT (kg) X 4 = total volume in the first 24 hours
Give first half in the first eight hours
Give second half over the following 16 hours
Consider I’ll be there in after the first 24 hours
What is the lethal triad of trauma
Acidosis
hypothermia
coagulopathy
Pneumoperitoneum for surgery can cause pressure and decrease blood flow to kidneys causing retained sodium and activation of RASS and decreasing UOP—-
Anesthetic caution
Do not give too much volume do to transient intraoperative oliguria
Fluid recommendation for sepsis
Aggressive early fluid replacement
This liposuction technique is common and the risk is _____ With greater than 5 L removed
Tumescent technique
Cardio pulmonary complications and collapse
Goals of goal directed fluid therapy
Adequate O2 delivery to tissue
Normothermia
Prevention of fluid access
Adequate delivery of oxygen to tissues is measured by
Preload
Adequate hemoglobin
Normal cardiac indices
SVI
Six acceptable levels of goal directed fluid therapy
Ph
Lactate
Anion gap
Coagulation profile
Electrolytes
Glucose
What fluid should be used for resuscitation in nephrotic syndrome
Albumin
Hyperchloremia may contribute to watch dysfunction
Renovascular construction
Judicious use of fluid in renal patients is important, these patients have a tendency of what metabolic dysfunction
Hyperchloremic metabolic acidosis
And cerebral edema neurosurgical patients do not give what fluid
Glucose containing solutions as they exacerbate intercranial ischemia
Fluid considerations with congestive heart failure
Judicious load management due to risk of postop Thirdspace redistribution and increased cardiac work
Disadvantage of colloids and caution with patients with this electrolyte abnormality due to binding proteins
Hypocalcemia
