Perioperative Medication and IV Fluids Flashcards
Diabetes Medications
Anticipate elevated BG post-op
Continue oral hypoglycemic agents until morning of - then switch to sliding scale insulin
Administer IV insulin and dextrose w/ long procedures
Avoid Metformin on day of and 72 hours after - decreases renal perfusion
Cardiovascular Drugs
BB
ACEI
CCBs
Alpha-2 Agonists (Clonidine)
Diuretics
BB: Beneficial, decrease M/M - take morning of
ACEI: Increase peri-op HOTN and post-op HTN - hold on day of
CCBs: appear cardioprotective, not much known
Alpha-2 Agonists (Clonidine): More problems w/ withdrawal rebound HTN
Diuretics: DC 48 hrs pre-op - risk hypovolemia and HOTN
-Loop diuretics are the worst for this
Gastrointestinal Agents
H2 Blockers & PPI: Decrease stress-related mucosal damage and aspiration risk
Take night before surgery
Pulmonary Agents
Beta-agonists & Anticholinergics
Leukotriene inhibitors
Corticosteroids
Theophylline
Beta-agonists & Anticholinergics: beneficial post-op, take AM of
Leukotriene inhibitors: AM of and resume when PO tolerated
Corticosteroids: continue and may need 2-3X dose
Theophylline: DC night before - serious toxicity risk
Antihyperlipidemic Agents
Niacin/Fibric Acid: DC - interfere w/ bowel absorption w/o anti-inflammatory effects
Atorvastatin/Pravastatin: Continue due to anti-inflammatory effects
-slight risk of rhabdomyalisis
Thyroid and Antidepressant Medications
Thyroxine: safe to withdraw 5-7 days - resume when PO tolerated
-If longer than 5-7 days, give 80% dose parenteral
SSRI: easier to leave on, can hold 2-3 days w/o issue
- Take morning of and resume w/ PO
- May increase bleeding due to serotonin effect on platelet migration
Antiplatelet Agents and NSAIDS
ASA: last 7-10 days; keep on for vascular surgery
-May DC and supplement w/ LMWH
Dipyridamole: no data, short 1/2 life
Clopidogrel/Ticlodipine: DC 5 days pre-op unless w/in 1 year drug-eluding stent or 1 mo bare metal stent placement
NSAIDs: DC 7-10 days before, use Tylenol instead
Most Concerning Medications
Plavix (Clopidogrel)
Warfarin
ASA
Metformin
Total Body Water
Directly proportional (70%) to muscle mass
Inversely proportional to fat (10%)
ICF = 2/3 TBW; K+, Mg+, phosphate, sulfate, protein
ECF = 1/3 TBW; Protein big player, Na+ main cation
Normal Osmolarity
285 osmol/L
Adverse Effects of IV fluids
NS
LR
D5W
NS: fluid overload, hypernatremia, metabolic acidosis from hyperchloremia
LR: fluid overload, hyponatremia, hyperkalemia
D5W: Hyponatremia
Severe Hypovolemia/Hypovolemic Shock Volume Replacement
Rapid infusion 1-2 L NS until sx impaired
If bleeding - PRBCs until Hct up to 35%
Crystalloids are just as effective to expand plasma volume as colloids - just need 1.5-3X more
-May cause hyperchloremic metabolic acidosis - sodium bicarb to correct
Mild/Moderate Hypovolemia
Rate of administration > rate of loss
Urine output + 50 mL/hr + GI loss
Administer at rate 50-100 mL/hr greater than estimated loss
Volume Replacement
Hypernatremia
Hyponatremia
Blood Loss
Hypokalemia/metabolic acidosis
Hypernatremia: Use hypotonic solution
Hyponatremia: Use isotonic/hypertonic saline
Blood Loss: Isotonic saline +/- blood
Hypokalemia/metabolic acidosis: Add potassium
Hypernatremia Correction Methods and Rate
Slow correction: 0.5 mEq/L or 10 mEq/L with goal 145
IVF: more hypotonic solution means less required volume and has a lower risk of cerebral edema
Madras formula to calculate rate infusion
