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60 Cards in this Set
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A&P EXAM 2 LECTURE 2: VASCULAR ACCESS
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A&P EXAM 2 LECTURE 2: VASCULAR ACCESS
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What are the purposes of IV placement?
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1. NPO
2. fluid loss 3. blood loss 4. drug adm. |
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Types of IV fluids?
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1. crystalloid
2. colloid 3. blood products |
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Fluid Vol Distribution
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60% TBW
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Osmolality
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Concentration of an osmotic solution per 1 Kg of solvent.
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Osmolarity
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.... per Liter of fluid.
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What is the effect of large protein molecules across capillary membranes?
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Produces colloid osmotic pressures.
Normal: 28 mmHg Note: ions produce osmotic pressures across cell membranes, but NOT capillary membranes. Normal: 285 mOsm/L |
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Normal ranges for:
1. Na 2. K 3. Cl 4. HCO3 5. Ca |
Na: 135-145 mEq/L
K: 3.5-5.0 Cl: 100-106 HCO3: 22-26 Ca: 8.5-10 |
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What is the definition of an equivalent?
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The amount of electrolyte or ion that provides 1mol of electrical charge.
Can replace with 1g of hydrogen. 1 mol Na = 1 equiv 1 mol Ca = 2 equiv |
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mEq/L =
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(mg/100ml/ atomic weight)*valence*10
Slide 13 |
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Normal Sodium and Osmolatlity values:
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Normal saline: 154 (308 mOsm/kg)
Normal pt: 140 (285-290) Lactated Ringers: 130 (273) |
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Tonicity of fluid dictates:
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Whether the soln should be delivered via peripheral or central venous route.
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What are some effects of solutions that differ greatly from normal range?
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1. tissue irritation
2. pain on injection 3. electrolyte shifts 4. inflammatory 5. enhanced clotting processes 6. phlebitis and thrombophlebitis |
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Very Hypotonic IV soln, i.e. 1/4 NS, can cause RBCs to:
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Swell and burst
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What is the total fluid replacement therapy for healthy adults?
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2500 ml/day
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4-2-1 Rule (A rule for estimating fluid replacement)
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Ex. 70kg pt.:
4ml/kg/hr * 10kg = 40 ml/hr 2 * 10 = 20 1 * 50(remainder) = 50 70Kg = 110ml/hr If NPO is 8hrs, then 8*110 = 880ml |
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What are the normal ranges of sensible fluid loss perioperative?
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2-4 ml/kg/hr minor surgery
4-6 .. moderate 6-10... major |
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Crystalloids
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Aqueous soln of LOW MW ions with or without glucose.
Ex: NS, LR |
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Colloid
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Aqueous soln of high MW substances.
Maintain plasma colloid oncotic pressure. Ex: Albumin, Hetastarch |
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Blood products help to:
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Improve O2 carrying capacity.
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Some IV fluid generalizations that are good to know:
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1. crystalloids are as effective as colloids in restoring intravascular volume if given in sufficient amount.
2. crystalloids require 3X vol of colloids/blood when replacing lost volume. 3. pt have extra cellular deficit MORE than intravascular deficit. 4. Colloids correct faster |
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Lactated Ringers
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Lowers Na level
Hypotonic (273 mOsm/L) |
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NS 0.9% NaCl
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Tx hypochloremic metabolic alkalosis.
PRBC dilution |
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D5W & D5NS
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Replace pure H2O deficit
Maintenance fluid pt w/Na restrictions. |
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Crystalloid distribution
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Slide 27
Print out |
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Colloid
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Generally admin in vol equivalent to vol of blood lost.
Ex.: 1. albumin 2. dextran 3. hetastarch |
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Colloid distribution
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Draw out the distribution
. |
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Hetastarch facts
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Composed of chains of glucose.
No antigenic, ABO interference Prolong PT, aPTT, bleeding > 20ml/kg. |
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What are some hetastarch contraindications?
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1. hydroxyethyl ether allergy
2. CHF 3. coagulopathy 4. renal dz (oligouria/anuria) |
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Blood products
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PRBC
FFP Cryoprecipitate Platelets Cell saver Whole blood |
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1 PRBC is how much Hct increase?
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By 3% or Hb to increase 1g/dl
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Recommedations for RBC:
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1. not usually indicated when Hb is greater than 10g/dl
2. almost always indicated when it's less than 6g/dl |
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Transfusion recommendations
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Platelets < 50K
Target > 100K/mm3 Each unit increases 5-10K/mm3 |
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Transfusion Recommendations for FFP
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Fresh Frozen Plasma
NOTE: Plasma makes up 55% of blood. Contains clotting factors. 1. for urgent reversal of warfarin 2. correction of coagulation factor deficiencies 3. for elevated PT or PIT 4. correction of microvascular bleeding |
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Fresh frozen plasma
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1. contains all plasma proteins and CF (clotting factors).
2. each unit increases CF by 2-3% 3. warmed to 37C 4. same infectious risk as PRBC. |
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Cryoprecipitate
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1. Do not need it to be ABO type.
2. contains factors: VIII, fibrinogen, von Willebrand factor, and XIII. NOTE: von Willebrand dz: hereditary coagulation abnormality. Lacks von Willebrand factor which is required for proper platelet adhesion. |
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Recommendations for cryoprecipitate
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1. prophylaxis in nonbleeding pts with Von Willebrands dz.
2. correction of microvascular bleeding. |
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Where do we put IVs in the upper extremities?
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1. dorsum of hand
2. forearm 3. antecubital fossa (cephalic, basilic) |
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.... in the lower extremeties?
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1. dorsum of foot
2. femoral vein |
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Other sites for IVs?
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1. external/internal jugular veins.
2. subclavian vein |
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Things you need for IVs
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1. gauze
2. alcohol wipes 3. tourniquet 4. catheter 5. IV tubing 6. tape and tegaderm 7. lidocaine |
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Talk to pt about IV experience
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Ask:
Have u ever had an IV done before? Location that was most successful for you? Explain procedure |
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IV prep
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1. apply tourniquet
2. maximize venous engorgement 3. locate suitable vein 4. clean/disinfect |
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IV insertion
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1. apply traction
2. insert angiocath 3. watch for flash in hub 4. advance catheter 5. release tourniquet |
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What are the indications for arterial lines?
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1. BP monitoring
2. blood sampling 3. deliberate hypotension |
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Sites for arterial lines?
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1. radial
2. brachial 3. femoral 4. dorsalis pedis |
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Radial artery vs. Ulnar artery
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Ulnar artery provides the majority of blood flow to the had in 90% of patients.
Ulnar artery is more difficult to cannulate. However, radial is usually chosen since ulnar provides the majority of blood flow to the hand. |
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What diseases would give contraindications to arterial cannulations?
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1. raynaud's syndrome
2. Buerger's dz |
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Raynaud's Dz
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Pale fingers due to constriction of vessels.
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Brachial artery
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Large easily identifiable vessel in the antecubital space.
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Femoral artery
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Prone to pseudoaneurysm and atheroma formation following cardiac catherization.
Possible higher rate of infection. |
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Dosalis pedis & Posterior tibial
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Reasonable alternative to radial or ulnar artery cannulation.
NOTE: should not be used in patients with diabetes or peripheral vascular disease (PVD). |
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Axillary
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Nerve damage may occur
Air or thrombus may quickly gain access to cerebral circulation during flush. |
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What are some risks to radial artery catherization?
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1. vascular thrombosis
2. distal embolization 3. proximal embolization 4. vascular spasm 5. skin necrosis 6. local infection |
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Indications for Central venous access
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1. monitoring central venous pressure.
2. fluid administration 3. TPN 4. air emboli aspiration 5. poor peripheral access |
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What is central venous access?
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It is used to:
1. administer medication or fluids 2. obtain blood tests (specifically the "mixed venous oxygen saturation"), 3. directly obtain central venous pressure. |
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Contraindications to central venous catherization:
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1. R atrial tumors
2. fungating tricuspid valve vegetations. |
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Routes of central venous?
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1. peripherally inserted central cather (PICC)
2. femoral vein 3. external/internal jugular 4. subclavian vein |
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Complications of central venous?
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1. pneumothorax/hemothorax
2. air embolism 3. arrythmias 4. infection |
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Does size of catheters really matter?
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YES
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