Keeping the Balance:
Achieving Desired Outcomes
with CRRT
Leslie SwadenerSwadener-Culpepper
RN, MSN, CCRN, CCNS
Critical Care Clinical Nurse Specialist
The Medical Center of Central GA
Macon, GA
©
LSCRN
Objectives
„
At the conclusion of this educational
session, the learner will be able to:
1) Assess and intervene for the CRRT patient
experiencing intravascular volume and electrolyte
imbalance issues.
„ 2) Describe appropriate changes to dialysate and
replacement fluid admixtures to achieve
appropriate patient chemistry values.
„ 3) Discuss potential uses for CRRT in Sepsis and
CHF
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LSCRN
Function of the Kidney
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Urine formation
Excretion of wastes
Fluid regulation
Electrolyte regulation
Blood Pressure control
Red Blood Cell synthesis and maturation
Acid Base Balance
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Renal Failure
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Pre Renal
Intra Renal
Post Renal
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Renal Failure –
Patient Care Problems
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fluid overload
Altered electrolyte balance
Potential infection
Altered acid base balance – metabolic acidosis
Altered nutrition status
Altered excretion of metabolic wastes – uremic
syndrome
Altered pulmonary status
Altered GI function
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Interventions for Renal Failure
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Intermittent Hemodialysis (IHD)
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Usually done for 2-6 hours every
other day.
Complications:
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Hypotension, Arrhythmias,
Cerebral edema,
Coagulopathies, Infection, Air
embolism
NO resemblance to normal kidney
function.
Contraindicated in Hypotension
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Peritoneal Dialysis
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Uses abdominal viscera as
semipermeable membrane to
remove toxins.
Contraindicated in peritonitis,
abdominal surgery, adhesions,
pregnancy
Complications:
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peritonitis, respiratory distress
atelactasis/pneumonia,
perforation of bowel and/or
bladder
Difficult to maintain
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LSCRN
Interventions for Renal Failure
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CRRT (Continuous
Renal Replacement
Therapy)
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Any extracorporeal blood
purification therapy intended
to substitute for impaired
renal function over an
extended period of time and
applied for or aimed at being
applied for 24 hours / day
An extracorporeal blood flow
from access blood to return
blood through a hemofilter
producing ultrafiltrate
(effluent)
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Machine’s Galore!
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Alphabet Soup??
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Group of words
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Continuous
Renal
Replacement
Therapy
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CRRT Therapies
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SCUF
CVVH
CVVHD
CVVHDF
What’s that CAVH stuff?
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CRRT Therapy
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Fluid management
Solute management
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Electrolytes
Waste products
Slow continuous
24 hour system
Assists to maintains homeostatic mechanisms &
hemodynamic stability
Works better to normalize hemodynamics, f&e
balance and waste management for patients in a
catabolic state
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Facility Differences
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ICU only?
Who is minding the store?
CRRT technicians?
1:1 care?
24 hr/day vs overnight?
Early vs Late
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Objectives of Therapy
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Promote hemodynamic stability
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Recurrent hypotension
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Worsens organ / tissue perfusion and contributes to organ
dysfunction / failure.
worsens ATN
Intolerence of Intermittent dialysis
Inadequate treatment
Nutritional Support
F&E, Acid/Base Balance
Promote healing and recovery
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Treatment Goals
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Improve hemodynamic status
Maintain pH
Maintain fluid balance
Prevent further renal damage
Decrease LOS (ICU and hospital)
Increase chance of renal recovery
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Advantages of CRRT
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CV Stability
Minimize hypotension
Safe / flexible F&E
management
Creates “space”
space” for
required fluids and or
nutrition
administration
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Minimize rapid ICP
changes
Simple procedure
Continuous removal
(mimics kidney
function more closely)
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Patient Candidates
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SOLUTE management
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MODS/Sepsis
Catabolic metabolism
ARF/ESRD
Nutritional Support
Trauma
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FLUID management
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Unstable on IHD
ARF/ESRD
ARDS
Organ Transplants
Cardiac Surgery
Diuretic Intolerance
Burns
Volume overload
CHF
Chemotherapy
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Principles of Dialysis
(remember kidney function?)
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Fluid balance & regulation
Restoration of electrolyte balance
Removal of toxins & metabolic waste
Regulation of pH
Key to success is the constant refilling of
intravascular volume.
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Fluid Distribution
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Body Water
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64% Intracellular
25% Interstitial
3% Minor components
8% Intravascular
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Body Water Distribution
Water in the human body
Water consumption:
. drinking water (1.5 liters per day)
. water in food (0.9 liters per day)
. water produced during the metabolism of food (0.6 liters per day)
Water disposal:
. respiration (0.5 liters per day)
. sweating and perspiration: (0.9 liters per day or more in hot weather)
. urine (1.5 liters per day)
. feces (0.1 liters per day)
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Renal Regulation
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Electrolytes
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Sodium
Potassiuim
Chloride
Calcium
Phosphate
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Magnesium
Bicarbonate
Water
Glucose
Urea
ACID BASE BALANCE
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Hydrogen Ions
Bicarbonate Ions
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Anatomy of a Filter
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Standard blood flow is
COUNTER CURRENT
to Dialysate flow.
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Transport Mechanisms
of Fluid and Solutes
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Ultrafiltration
Osmosis
Diffusion
Convection
Adsorption
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Ultrafiltration
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Movement of
FLUIDS through a
membrane caused
by a pressure
gradient.
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Diffusion
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Movement of
SOLUTES from
an area of
higher
concentration to
an area of lower
concentration.
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Factors affecting diffusion
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Dialysate temperature
Dialysate flow rate
Blood flow rate
Molecular weight
(size) of solutes
Concentration
gradients
Permeability of
membrane
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Osmosis
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Movement of
WATER across a
semisemi-permeable
membrane.
Like diffusion,
osmosis is based
on solute
concentration.
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Convection
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The movement of SOLUTES with a water
flow. Also called “solvent drag”
drag”
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the movement of membrane permeable
solutes with ultraultra-filtrated water.
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Adsorption
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Certain membrane materials display
adsorptive characteristics
„ Surface adsorption of
solute onto the membrane
„ Bulk adsorption
within the membrane
when the molecules
can permeate it.
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CRRT Therapies
„ SCUF
„ CVVH
„ CVVHD
„ CVVHDF
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SCUF: Slow Continuous Ultrafiltration
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Access: Venous via
blood pump.
Return: Venous
Effluent only
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Uses ultrafiltration
(pressure) to clear
excess fluids.
Convective loss
Used in fluid overload
situations
Usually short term
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CVVH: Continuous VV Hemofiltration
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Access: Venous via
blood pump.
Return: Venous
Effluent includes
patient volume
removal and
replacement solution
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Adds replacement
solution as
convective fluid.
Pre vs Post filter
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REPLACEMENT Solution: CVVH
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Uses ultrafiltration &
convection as primary
mechanisms
Solute clearance determined
by rate
Pre filter replacement:
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(decreases Hct)
Hct) can assist
with anticoagulation
Pre filter infuses into arterial
(access) line
Can NOT use u/f chemistries
to assess adequacy of
treatment
? Loss of efficiency, little
literature to support use
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Post filter replacement:
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infuses into venous (return
line)
Post filter replacement can
INCREASE the need for
anticoagulation
“churning effect”
effect”
Can use u/f chemistries
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CVVHD: Continuous VV
Hemodialysis : DIALYSATE
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Adds Dialysate
No replacement
Dialysate composition
dramatically alters
electrolyte exchange /
transfer to effluent
Adds osmotic / convective
transport
Dialysate is altered to
impact rate & amount of
solute clearance for key
electrolytes.
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Access: Venous via blood
pump.
Return: Venous
Effluent includes patient
volume removal and dialysate
used.
Dialysate rate determines
RATE of clearance.
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„ Dialysate composition
determines AMOUNT of
clearance.
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CVVHDF:
Continuous VV Hemodiafiltration
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Closest to
conventional
hemodialysis
All mechanisms in play
(ultrafiltration,
ultrafiltration,
osmosis, diffusion,
adsorption)
New evidence that
this is used to make
up for slower rates of
older CRRT machines.
New machines with
higher flow rates for
blood and fluids may
not have CVVHDF
mode.
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Access: Venous via
blood pump.
Return: Venous
Effluent includes
patient volume
removal and all
replacement solution
and dialysate used.
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New Trends in CRRT
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Faster blood flow rates, approaching
200ml / min.
CVVHD vs CVVHDF
Much faster flow rates on solutions (2
liters / hour for each, if both used)
Some machines don’
don’t provide CVVHDF r/t
speeds of blood flow & dialysate.
dialysate.
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Alternate Applications….
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Sepsis
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Literature unclear on exact
mechanism
Adsorption?
Septic mediators and
inflammatory cytokines
Closer monitoring of
intravascular volume /
perfusion.
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Alternate Applications….
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CHF
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Smaller Version of SCUF
Designed for M/S &
outpatient settings
Ultrafiltration ONLY
Can be done with hi flo
peripheral catheters
Filters only hold 40cc total
COST !!!
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Nursing Considerations
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Hypotension,
dehydration
Electrolyte and acid
base imbalances
Hypothermia
Hyperglycemia
Clotted filters and
circuits
Catheter Problems
Blood leaks
Bleeding
Inadequate blood
flow
Infection
InterInter-Intra disciplinary
approach
Ethical issues
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Hypotension
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Is it volume depletion,
or something else?
BP change is a SYMPTOM of altered CO determinants
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Preload, Afterload,
Afterload, Contractility (SV) and HR
Obviously, think volume (Preload) but don’
don’t forget to consider the
other factors as well.
„ Is the patient vasodilated from sepsis, anaphylaxis, neurogenic
shock…
shock… anesthesia etc. (afterload
(afterload))
„ Is the heart pumping effectively? (contractility)
„ Is the heart rate too fast or too slow?
Measurement of CVP, PCWP or other volume indicators
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Volume Depletion
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REMEMBER:
You can be overloaded
in the cells & tissues
and DEHYDRATED in
the vascular space!
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STEP ONE – If you are
REPLACING fluid, stop
REMOVING fluid.
Numbers aren’
aren’t always
everything.
Methods to encourage
vascular refilling:
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Proteins
High molecular weight
fluids
Sodium (simulation of
sodium modeling)
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Electrolyte and acid base
imbalances
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Usually require changes to dialysate /
replacement fluids…
fluids… but then correction
can take up to 24 hours.
Some nephrologists prefer to leave
solutions alone and balance electrolytes
the old fashioned way (mini bags!)
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Hypothermia
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Adsorption of inflammatory
(septic) mediators decreases the
inflammatory response.
Cooling of blood as it moves through
the circuit
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If pt hypothermic…
hypothermic…
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Use blood warmers (if available)
Use Warming blanket
Wrap filter and tubing in wash cloths /
towels
Tuck as much tubing as possible under the
Warming blanket.
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Hyperglycemia
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Stress response
Molecule too large
to filter out
Dialysate solutions
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Clotted filters and circuits
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Never flush blood back
into a patient
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Clots could dislodge
Reprime and restart
Watch for high FILTER
pressures.
TMP – indicative of
pressure of blood as it
passes through the
filter.
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Filter Anticoagulation
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Standard Heparanization
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Filter vs Patient
Risk of HIT
Citrate Anticoagulation
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Pending FDA approval (off label application)
Protocols have been developed & used
Research is active in this area
More labor intensive?
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Labs (serum Ca+ levels)
Use of replacement solutions
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Lower Hct of blood passing through filter
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Catheter Problems
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Clotting / Kinking…
Kinking…
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Access side – look for extremely
NEGATIVE pressure (indicates it
is pulling really hard to maintain
flow)
Return side - look for extremely
POSITIVE pressure (indicates it
is pushing really hard to return
blood to patient)
Try to reposition…
reposition…
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Use a sandbag
Flip catheter over (sometimes
this gets it off a vein valve)
Switch access and return to
opposite ports of catheter.
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Insertion Sites
Femoral
Subclavian
Internal Jugular
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Femoral Site
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19cm or longer catheter
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Advantages
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Safest insertion
Easiest insertion
Relatively short term
Disadvantages
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Highest infection rate
Recirculation issues
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Subclavian Site
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1515-20cm catheter
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Advantages
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Decreased recirculation
Decreased stenosis
Relatively long term
Easy to dress and keep
clean
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Disadvantages
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Technically difficult
insertion
Risk of Subclavian arterial
stick
Pneumothorax
Subclavian Stenosis
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Internal Jugular Site
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19cm Right : 23cm Left
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Advantages
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Decreased recirculation
Decreased stenosis
Relatively long term
Disadvantages
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Technically difficult
insertion
Risk of Carotid arterial stick
Proximity to mouth and
trachea (infection)
Difficult to bandage
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Recirculation Problems
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Recirculation is LEADING CAUSE OF FILTER CLOTTING
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Adequate venous return imperative!
Reversal of “arterial”
arterial” and “venous”
venous” ports
MAP issues
Hemodynamic instability
Length of catheter
Anatomic location of catheter tip
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Inadequate blood flow
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Despite the fact that the blood is
“PUMPED”
PUMPED” through the filter, you
need to consider…
consider…
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Venous return.
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Low MAP (50ish) will either set off
alarms or set up recirculation.
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Pt’
Pt’s with extremely low BP…
BP…
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Think about your infusions and meds
being infused in close proximity to
dialysis catheter.
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Blood leaks & Bleeding
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BLD (Blood Leak Detector)
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Checks for microscopic blood in effluent
Blood in effluent indicates microscopic rupture of filter
membranes.
RBCs should never be present in effluent.
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All you can do is change the set.
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Pt can bleed…
bleed…
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Anticoagulants
DIC in critical illness
Clotting factors used up “clotting filters”
filters”
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Dialyzer Reaction
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Allergic type / Anaphylactic Syndrome
Type A – Code, usually within 5 minutes
of exposure to filter
Type B – Less severe
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STOP treatment
Antihistamines
Epinephrine
BP support
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Air Embolism
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Air is introduced into circuit
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Air detector required in all machines.
Symptoms:
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Can result from disconnect
Bags run dry
Chest Pain
SOB, cough
Visual issues
LOC changes
Seizures
Place Pt on Left side
TRENDELEBURG
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Infection control
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Dialysis Catheters
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Patient lifeline
Important that sterile
technique be
maintained
Possible to run out of
sites
Unless life
threatening, ports
should be reserved
for Dialysis only
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LSCRN
Ethical Dilemmas
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Patient selection
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Appropriateness
Clash of specialties
Timeliness of
implementation
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Can CRRT fix the underlying problem?
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Is it a CRRT issue at all?
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End of Life issues – just because we
can…
can… doesn’
doesn’t mean we should
©
LSCRN
Thank You!
„ Speaker contact info:
Culpepper.leslie@mccg.org
©
LSCRN