as given by Dr. McKinnon

1. Fluids, Electrolytes,
and Anesthesia

2. Total Body Water
 2/3 of body weight is water (infants slightly more, women slightly less)
 Use kg x 0.6 in men and kg x 0.5 in women

3. Total Body Water Continued
 Protein is the main determinant of intravascular and interstitical
compartment ONCOTIC pressure
 Sodium is the main determinant of intracellular and extracellular OSMOTIC
pressures
 Plasma Osmolarity (Normal = 290 +/- 10) = (2 x Na) + (glucose/18) +
(BUN/2.8)
 Normal K requirement is 0.5-1.0 mEq/kg/day
 Normal Na requirement is 1-2 mEq/kg/day

4. Fluid Composition

5. Fluid Replacement
 4, 2, 1 Rule (every 10kg)
 Best indicator for fluid status is urine output
 Assume 0.5-1L/hr fluid loss for open abdominal operations
 Insensible fluid losses are around 10mL/kg/day (75% sweat, 25% resp)
 Use LR first 24hrs then switch to D5 ½ NS w/ 20mEq K for major GI
surgery
 For pancreas, biliary system, small intestine, and large intestine losses,
replace with LR (bicarb and potassium lost)

6. Fluid Replacement Continued
 NEVER bolus NS w/ K added – cardiac arrest
 Replace GI losses mL for mL
 Do not replace urine mL’s (just keep at least 0.5mL/kg/hr)

7. Sodium (135-145)
 Hypernatremia – almost always due to dehydration (usually poor intake –
95%, also can be over-diuresis or DI)
 Symptoms include irritability, restlessness, ataxia, weakness, and seizures
 Free water deficit (L) = TBW x [(actual serum Na – ideal serum Na)/ideal serum
Na]
 Do not drop Na faster than 0.5-1meq/L/hr – cerebral edema
 Hyponatremia – fluid overload (usually iatorgenic, can be SIADH)
 Symptoms include N/V, headaches, delirium, seizures, stupor, coma
 Treatment – water restriction, diuresis and hypertonic saline (symptomatic)
 Do not increase Na faster than 0.5meq/L/hr – central pontine myelinosis
 Pseudohyponatremia – from hyperglycemia or hyperlipidemia

8. Potassium (3.5-5.0)
 Hyperkalemia – usually from renal disease (80%), also meds, aldosterone
deficiency and adrenal insufficiency
 EKG – peaked T waves
 Treatment – calcium gluconate, sodium bicarbonate (exchange K for H), insulin
and dextrose (drive into cells w/ glucose), kaexylate, Lasix, albuterol, dialysis
 Pseudohyperkalemia – hemolysis of blood sample
 Hypokalemia – usually from diuretics, also poor intake (TPN) and GI losses
(NGT, N/V, diarrhea)
 EKG – depressed T wave
 Treatment – potassium chloride (also check Magnesium)

9. Calcium 8.5-10.5 (4.5-5.5)
 Hypercalcemia – usually hyperparathyroidism (parathyroid adenoma) or
malignancy (lung or breast) (90%)
 Symptoms include lethargy, weakness, N/V, hypotension, arrhythmias, shortened
QT, kidney stones, stomach ulcers, decreased reflexes
 Treatment (>13) includes volume infusion (no LR), Lasix, dialysis
 Malignancy – bisphosphonates, calcitonin, steroids, mithramycin
 Hyperparathyroidism – parathyroidectomy after recovery
 Hypocalcemia – usually previous thyroid surgery, also rapid blood transfusion,
renal failure, or pancreatitis
 Symptoms (under 8), perioral tingling, Chvostek’s sign, Trousseau’s sign,
laryngospasm, hyper-reflexia, prolonged QT
 Treatment includes calcium gluconate and vitamin D (check magnesium)
 Hypoproteinemia – add 0.8 to Ca for every 1g decrease in protein

10. Magnesium 2-2.5
 Hypermagnesemia usually from renal failure w/ mg intake
(laxatives/antacids) also burns or trauma
 Symptoms include lethargy, weakness, N/V, hypotension, arrhythmias,
decreased reflexes
 EKG - >10 complete heart block, >13 risk for cardiac arrest
 Treatment is calcium (competitive antagonist), diuretics, and dialysis
 Hypomagnesemia usually from diuretics also EtOH abuse or malnutrition
 Symptoms (<1) include irritability, tremors, confusion, hyperreflexia, tetany,
seizures, prolonged QT, ventricular arrhythmias (torsades)
 Treatment is magnesium

11. Phosphate 2.5-4.5
 Hyperphosphatemia usually from renal failure also hypoparathyroidism or
tumor lysis syndrome
 Symptoms (usually asymptomatic) can include ectopic calcification, renal
osteodystrophy
 Treatment is sevelamer chloride (binder in gut) low phosphate diet, and dialysis
 Hypophosphatemia usually from phosphate shifts and in the setting of
EtOH abuse (refeeding syndrome) also respiratory alkalosis,
hyperparathyroidism and DKA treatment
 Symptoms include failure to wean from vent, muscle weakness, increase in
infection rate
 Treatment is potassium phosphate

12. Renal failure
 Electrolyte abnormalities – decreased sodium and calcium, increased
potassium, phosphate, and magnesium
 Avoid magnesium containing antacids and laxatives
 Indications for dialysis are fluid overload, increase K/Mg/Phosphate/BUN,
metabolic acidosis, uremic encephalopathy, uremic coagulopathy,
poisoning

13. Acid Base
 Normal Values
 pH 7.35-7.45
 CO2 35-45
 HCO3 22-26
 Lungs control CO2 (rapid process)
 Kidneys control HCO3 (slow process)

14. Respiratory Acidosis/Alkalosis
 Alkalosis – hyperventilation like PE
 Chronic cases are associated with hypokalemia
 Acidosis – hypoventilation like COPD exacerbation

15. Metabolic Alkalosis
 Loss of H+ or gain of HCO3- (GI or kidneys)
 Gastric fluid loss – hypokalemic, hypochloremic metabolic alkalosis w/
paradoxical aciduria (K/H exchanger)
 Over diuresis (furosemide or HCTZ) or dehydration – contraction alkalosis
– relative increase to body mass
 Hypertensive syndromes (Conn’s, secondary hyperaldosteronism,
Cushing’s)
 Treat gastric/over diuresis/contraction with NS bolus (acetazolamide
diuresis or dialysis for fluid overloaded) and hyperensive types with
spironolactone

16. Metabolic Acidosis
 Increased H+ or loss of HCO3-
 Anion gap or non-anion gap – measured vs unmeasured anions
 Na+ - (HCO3- + Cl-) Normal <10-15

17. ASA Class
Class Description
1 Healthy
2 Mild disease without limitation (controlled hypertension, obesity,
diabetes mellitus, significant smoking history, older age)
3 Severe disease (angina, previous MI, poorly controlled hypertension,
diabetes mellitus with complications, moderate COPD)
4 Severe constant threat to life (unstable angina, CHF, renal failure, liver
failure, severe COPD)
5 Moribund (ruptured AAA, saddle pulmonary embolus)
6 Donor
E Emergency

18. Revised Cardiac Risk Index
 1 point per risk factor (6 is max)
 High-risk procedure (intra-peritoneal, intra-thoracic, major vascular)
 Hx of ischemic heart disease (MI, positive stress test, angina, nitrate use)
 Hx of CHF (pulmonary edema, paroxysmal nocturnal dyspnea, S3)
 Hx of cerebrovascular disease (TIA or stroke)
 Preop tx w/ insulin
 Preop creatinine >2.0

19. Risk of Major Cardiac Event
 MI, pulmonary edema, V fib, cardiac arrest, and complete heart block
 Class III and IV get non-invasive cardiac testing (II if poor or indeterminant
functional status) also benefit from beta-blocker
 Class I does NOT need testing or beta-blocker
 Wait 6-8 weeks after MI for elective surgery (10% mortality otherwise)
 CHF highest risk factor for post-op mortality

20. Intubation Basics
 ET tube size 7-8
 End tidal CO2 best test for endotracheal placement, place 2cm above
carina
 Sudden increase in ETCO2 – atelectasis, sudden decrease – vent
disconnection, air embolis, or PE

21. Rapid Sequence Intubation
 Used for increased risk of aspiration (recent oral intake, GERD,
gastroparesis, pregnancy, bowel obstruction)
 Pre-oxygenation, IV induction agent, IV paralytic

22. IV Induction Agents
 Etomidate – 0.15-.03 mg/kg TBW, fast acting (unknown mechanism), good
anesthetic and amnesic, NO analgesia, continuous infusion leads to adrenal
suppression
 Sodium Thiopental – 3-5 mg/kg TBW, barbiturate, fast acting, NO analgesia,
can cause hypotension and decreased cerebral flow
 Propofol – 1.5 mg/kg TBW, rapid distribution, unknown mechanism, NO
analgesia, metabolized in liver and by plasma cholinesterases, can cause
hypotension and respiratory depression, NOT IN EGG OR SOYBEAN ALLERGY,
NOT IN CHILDREN
 Ketamine – 1.5-2 mg/kg IBW, dissociation of thalamic and limbic systems,
cataleptic state (amnesia and analgesia), NO respiratory depression, good for
children, causes hallucinations/tachycardia/ increase secretions/increased
cerebral blood flow, NOT IN HEAD INJURY

23. Inhalational Induction Agents
 MAC (minimum alveolar concentration) – smallest concentration at which
50% of pts will not move w/ incision
 Small=more lipid soluble=more potent
 High=less lipid soluble=less potent
 Speed is INVERSELY proportional to lipid solubility
 Effects of inhaled agents – mechanism is unknown, anesthesia, amnesia,
+/- analgesia, blunts hypoxic respiratory drive, some myocardial
depression, short acting

24. Types
 Sevoflurane – most commonly used, expensive, fast onset, less myocardial
depression, less laryngospasm
 Desflurane – pungent, irritates airway, NOT for induction
 Isoflurane – pungent, irritates airway, NOT for induction
 Enflurane – do NOT use with epilepsy (can cause seizures)
 Halothane – slow, highest myocardial depression and can cause
arrhythmias, least pungent (good for children), can cause halothane
hepatitis
 Nitrous oxide – fast, minimal myocardial depression, usually used as a
carrier for sevoflurane or desflurane

25. Maintenance Anesthesia
 Usually combination of nitrous oxide, oxygen, and volatile anesthetic with
supplemental opiods and benzos
 Propofol can be used alone
 Fentanyl and versed drips
 Precedex – anesthesia and analgesia w/o decreasing respiratory drive
(good for early extubation protocols)

26. Narcotics
 All act on mu receptor in CNS and are reverse w/ Narcan
 Effects – profound analgesia, respiratory depression, blunt sympathetic
response
 Liver metabolism and kidney excretion
 Morphine – miosis, decrease cough, constipation, active metabolites can
build up in renal failure
 Demerol – miosis, tremors, fasciculations, seizures, AVOID in renal failure
(seizures) and pts on MAOIs (serotonin syndrome)
 Fentanyl – 80x strength of morphine, does NOT cross react w/ morphine
allergy
 Opioids and benzos synergistic

27. Paralytics
 Diaphragm – last muscle to go down and 1st to recover
 Neck/face – 1st to go down and last to recover
 Depolarizing and non-depolarizing
 Only Depolarizing agent is Succinylcholine
 Fast, short-actin, fasciculations at first
 Malignant Hyperthermia – defect in Ca metabolism, Ca is released from
sarcoplasmic reticulum causes muscle excitation-contraction syndrome, 1st sign
is increased end-tidal Co2, fever, tachycardia, rigidity, acidosis, hyperkalemia,
hypoxia, rhabdo. Treat w/ DANTROLENE.
 Hyperkalemia – depolarization releases K, DO NOT use in burns, neuro injury,
neuromuscular disorders, spinal cord injury, massive trauma pts

28. Non-depolarizing Agents
 Compete w/ Ach at the Ach receptor, slower than depolarizing
 Rocuronium – very fast, intermediate duration, hepatic metabolism
 Pancuronium – slower, long duration, no hypotension, renal metabolism
 Cis-atracurium – slower, intermediate duration, Hoffman elimination, can
cause hypotension
 Vecuronium – fast, short duration, hepatic-biliary excretion
 Reversal
 Neostigmine/Edrophonium – blocks acetylcholinesterase, increases Ach
 Atropine/glycopyrrolate (Ach antagonists) – counteracts effects of Ach
overdose (salivation/diarrhea

29. Benzodiazepines
 Anxiolytic, anticonvulsant, amnesic, respiratory depression – NOT
ANALGESIC
 Hepatic metabolism
 Bind GABA receptors
 Versed (midazolam) – short acting, crosses placenta
 Ativan (lorazepam) – long acting
 Valium (diazepam) – long acting
 Overdose treatment – flumazenil (competitive inhibitor that may cause
seizures and arrhythmias)

30. Local anesthetics
 Increases action potential threshold (prevents Na influx)
 Hard to anesthetize infected tissues due to acidosis
 Epi allows higher doses to be used because it stays local
 No epi w/ arrhythmias, unstable angina, uncontrolled HTN, poor collaterals
(penis/ear), or uteroplacental insufficiency
 Allergic rxn
 Amides (have I in first part of name) – lidocaine, bupivacaine, mepivacaine –
RARE allergic rxn
 Esthers – tetracaine, procaine, cocaine – increased allergic rxn secondary to
PABA analogue

31. Local continued
 Length of action: bupivacaine > lidocaine > procaine
 Lidocaine max dosage – 5mg/kg (7mg/kg w/ epi)
 0.5mL/kg of 1% lidocaine
 Bupivacaine max dosage – 2mg/kg (3mg/kg w/ epi)
 Lidocaine toxicity – perioral paresthesias, visual and auditory
hallucinations, sedation, unconsciousness, seizures, respiratory depression,
arrhythmias, cardiovascular collapse

32. Epidural Anesthesia
 Pain receptors affected much more than motor receptors
 Bloody tap – insert at new level
 Block height is 3-4 levels above site of insertion (T5 affects cardiac)
 Contraindications to epidural/spinal – hypertrophic cardiomyopathy
(decrease afterload), cyanotic heart disease, aortic stenosis, liver disease
(bleeding risk), infection (epidural abscess), coagulopathy, anatomic
abnormalities, elevated ICP
 Benefits – decreases respiratory complications, decreases MI, increases
return of bowel function, no change mortality

33. Epidural Complications
 Morphine component - Respiratory depression, turn off epidural and do
airway management, less with dilaudid
 Lidocaine component – decrease in HR and blood pressure, turn epidural
down, fluids/phenylephrine/atropine, make sure not because of something
else
 Urinary retention – ALL need bladder cath
 Spinal headaches – HA worse sitting up, treat w/ rest, increase fluids,
caffeine, analgesics, blood patch if persists
 Abscess – increased risk when left >72hr, diagnose w/ MRI, treat w/
drainage w/ laminectomy
 Epidural hematoma – sudden localized back pain w/ paresthesias, then
motor + sensation loss +/- bowel/bladder