BS Periop Complications Flashcards
Describe how platelets respond to endothelial damage
Endothelial damage from tissue trauma, surgery etc
Exposes collagen -> activates platelets
Allows platelets to adhere to exposed collagen
What are 3 hypercoaguable disorders that are deficiencies (decreased anti-clot factors)
Protein C def
Protein S def
AT3 def
What is the final product of the clotting cascade
Thrombin (IIa)
Converts soluble fibrinogen -> insoluble fibrin
What scan should you get for PE if patient has a contrast allergy
VQ scan
If there is data that many TKA and some THA patients have asx DVT + PE post op, why not therapeutically AC them all?
Higher bleeding/hematoma complications (infection) requiring re-op
Mechanism TXA
Lysine analog
Blocks plasminogen -> plasmin
Prevents clots from dissolving
What are the current anesthesia guidelines for waiting on spinal with
LMHW
Xa inhibitors (-axabans)
Warfarin
Direct thrombin inhibitors (dabagatran)
Antiplatelets (clopidogrel)
LMHW - 24h
Xa inhibitors (-axabans) - 3d
Warfarin - 5d, normal INR
Direct thrombin inhibitors (dabagatran) - 5d
Antiplatelets (clopidogrel) - 7d
What is the data on compression stockings?
Vs pneumatic compression devices
No value for DVT prevention, post thrombotic protection
Vs pneumatic compression decreases proximal venous thrombosis
- And non-inferior to aspirin if portable! (improve compliance)
Mechanism:
ASA
NSAIDs
Celicoxib
ASA - irreversible bind COX in platatelets
NSAIDs - inhibit COX 1/2
Celicoxib - inhibit COX 2
Mechanism + reversal for coumadin
Xs vit-K clotting factors carboxylation
Factors 2,7,9,10 prot C,S
Reverse with vit K PO/IV, FFP
Mechanism heparin vs LMWH
What is the reversal agent?
Heparin: reversible Xa block via AT3, factors 2, 9, 11, 12
LMWH: reversible Xa block via AT3, factor 2
- Legit a shorter molecule than heparin
- Less HIT
- Decrease dose for renal dysfunction
Reverse w/ protamine sulfate
Mechanism rivaroxaban, reversal agent
Blocks Xa
Andexanet = reversal
Mechanism dabagatran + reversal agent
Blocks IIa (thrombin) only
Reverse = idarucizumab
What is the current recommendation for DVT prevention in THA/TKA in:
Pts w/ prev DVT
Pts w/ bleeding risk
Pts w/ normal risk
Hx DVT = meds + pneumatic compression
Bleeding risk = pneumatic alone
Normal = drugs and/or pneumatic
Diagnose: young overhead athlete, UE pain/heaviness, vein dilation and arm discoloration
Dx
Trt
Ax-subclav vein thrombosis
Presents like thoracic outlet syndrome
Dx: duplex > MRA > UE venogram
Trt: thrombolysis / first rib resection
What is the pulmonary manifestation of fat embolism syndrome
Trt
ARDS - 50% mortality rate
Ventilate w/ PEEP
- Open lung concept - recruit alveoli
What values indicate poor fluid resus
UOP
Lactate
BAD if
UOP<30cc/hr
Lactate > 2.5
Describe presentation of neurogenic shock
Trt
Warm, dry hands
- Lose sympathetic tone - blood pools peripherally
Low BP
Low HR (inappropriate response)
Trt: fluids + pressors
Malignant hyperthermia
- Mutation
- Mechanism
- Earliest sign
- Trt
Genetic defect transverse T tubule
- Dihydropyridine
- Ryanodine
Give anesthesia -> uncontrolled Ca release
Sustained muscle contraction
-Acidosis
- Damage muscle cells - release K (arrhythmia)
1st = unexplained rise in end tidal CO2
Trt = dantrolene = stabilizes ryanodine receptor = drops intracell Ca2+
