Table of contents
ASA Classification
ASA 1: Healty, fit patient
ASA 2: Patient with mild systemic disease (i.e. controlled Type 2 diabetes)
ASA 3: Patient with severe systemic disease that limits activity (stable CAD, COPD, DM, obseity)
ASA 4: Patient with incapacitating disease that is constant threat to life (unstable CAD, renal failure)
ASA 5: Not expected to survive without surgery (ruptured AAA, head trauma)
ASA E: For Emergency operations
Diet Guidelines
- 8 hours: after meal that includes meat, fried, fatty foods
- 6 hours: light meal (toast, crackers, clear fluid)
- 4 hours: breast milke or jello
- 2 hours: clear fluids (water, black coffee, tea, carbonated beverages, juice without pulp)
Medications
Drug | Continue/Discontinue | Notes |
GE reflux meds | Continue/Start | sodium citrate 30mL PO or ranitidine 150-300mg PO 30min-1hr pre-op |
Adrenal Suppression | Start | If on steriods, must give stress dosing of steroids because adrenals suppressed from exogenous steroids. |
Risk of DVT | Start | Heparin SC |
ASA | Usually Continue | |
Warfarin | Usually bridge to LMWH | |
Hypoglycemics | Stop All | due to NPO (if TIIDM may stop, but if Type I DM: definitely stop), can recheck glucose post-op and give insulin. |
Antidepressants (incl SSRI, MAOi) | Stop All | Stop the morning of OR |
Oxygen Therapy
Low Flow Systems:
- Usually non-invasive, provide consistent O2 flows 0-8 L/min.
- However FiO2 (Fraction of Inspired O2) is inconsistent (based on minute ventilation (tidal volume x RR)).
- If patient is tachypneic: FiO2 will be low because they will take in more air, and the steady flow (0-8 L/min) will be diluted.
- Nasal Canula (prong)
- Flow rates <5-6 L/min, if go higher will dry out mucosa + uncomfortable blowing air into nose.
- FiO2 estimated by adding 20% + 4% for each liter of O2 delivered (1L/min = 24% FiO2, 6L/min = 44% FiO2), considering patient breathing normally.
Reservoir Systems:
- Use small reservoir to accumulate O2 during exhalation, increasing the amount of oxygen available for next breath.
- Simple Face Mask (Hudson Face Mask) (Flow: min 6 L/min)
- Covers patient's nose and mouth (normally only nasopharynx is the reservoir for O2, but FM expands this reservoir)
- Flow rates at least >6L/min required, if go lower, CO2 will not be flushed out of mask.
- FiO2 = 55% approx if O2 flow 10L/min
- Non-Rebreather Mask (Flow 10-15 L/min)
- A separate bag to collect and concentrate oxygen.
- A series of valves cause expired air to be removed and not mixed with incoming O2.
- O2 flow rates 10-15 L/min required to keep bag inflated.....FiO2 >80%
High Flow Systems
- Flows up to 50-60 L/min --> meets or exceeds patient's flow requirement.
- Delivers consistent FiO2 regardless of minute ventilation (resp rate etc..)
- Venturi Mask
- Delivers specific FiO2 (pick valve) (24%, 28%, 35%, 50%)
- Can humidify air if wanted to.
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