Assessment of IV volume Flashcards
(31 cards)
How do you assess volume status?
Static markers = assess volume and/or pressure indices to estimate amount of fluid in entire CV system
What is the ROSE principle?
Resuscitation
Optimization
Stabilization
Evacuation
How can you assess fluid responsiveness?
Dynamic markers = used on principle of invoking short-ter changes in cardiac preload
Explain the Eisenhower matric of volumem assessment.
Explain the Farnk-Starling and Marik-Phillips curves in regards to fluid therapy
Respons to fluid bolus:
Hypovolemic: increased in preload with no increase in EVLW
Euvolemic: mild increase in preload with some increase in EVLW
Hypervolemic: small to no increase in preload but large increase in EVLW
Describe the terms unstressed and stressed volume. Which one is the main contributor to the mean systemic filling pressure (MSFP)?
unstressed volume = blood volume contained in highly distensible capacitance veins (majority of blood volume), that does not create a transmural pressure
stressed volume = volume of blood that creates transmural pressures above 0
–> = main contributor to MSFP
What are the 3 main driving forces of venous return?
- MSFP
- RAP
- resistance to venous flow (Rv)
What is the formula for venous return?
VR = (MSFP - RAP)/Rv
MSFP…Mean systemic filling pressure
RAP…Right atrial pressure
Rv…Resistance to venous flow
How can venous return be increased?
- increase in MSFP (via fluid bolus or venoconstriction)
- lowering of RAP (if too low –> venous collaps at thoracic inlet)
- lowering of Rv (via venodilation or increased venous compliance –> will also lower MSFP)
What needs to happen for a fluid bolus to be effective for increaseing MSFP?
Stressed volume must increase > than RAP
What are physical examination parameters indicative of hypovolemia?
- dry MM
- prolonged CRT
- paleness
- prolonged skin tent
- cool extremitites
- hypothermia
- weak or nonpalpable pulses
- tachycardia
- Tachypnea
- venous collapse
- high USG + decreased UOP
What are physical examination parameters indicative of hypervolemia?
- serous nasal discharge
- moist gums
- gelatinous skinfold
- peripheral edema
- bounding pulses
- distended jugular veins
- elevated jugular pulses
- low USG + high UOP
What are sensitivity and specificity for detection of hypovolemia on physical exam in people?
Sensitivity: 8%
Specificity: 75%
What is the sensitivity of throcic radiographs to detect hypovolemia in cats who experienced trauma according to Zulauf et al 2008?
19%
Explain the FALLS protocol by Lichtenstein et al 2012 (people) and its usefullness in resuscitation.
LUS is used to categorize patients in shock basend on dry lung/wet lung
= based on principle that hypovolemic patients that have not yet received a fluid bolus will have dry lungs
wet lung = > 3 B-lines in a single lung ultrasound window
Hypovolemic: dry lungs –> not develop wet lung with resuscitation
cardiogenic shock: wet lungs
distributive (e.g. sepsis): dry lungs with tendency to develop wet lungs sooner despite remaining clinically unstable
What is a static parameter? Give 8 examples of static markes of volume status
= measured at a single time point
= better at assessing volume status, but not a good marker for fluid responsiveness
= does not identify where a patient is on a the Frank Starling curve
- CVP
- PAOP (PCWP)
- CVC diameter
- cardiac POCUS
- Lactate
- Perfusion parameters
- Shock Index
- MAP
What are the 3 sites for assessment of the CVC?
- suprailiac (kidney)
- right intercostasl (transhepatic)
- subxiphoid (diphragmatic)
What changes can be seen on cardiac POCUS suggestive of hypovolemia?
- smaller LV
- smaller LA
- thicker LV walls
Does cardiac POCUS have a higher sensitivity in detecting changes in volume status than clinical exam?
Yes
What is the definition of fluid responsiveness?
capacity to improve perfussion following a fluid challenge
How many haemodynamically unstable patients in ICU (people) will not respond to a fluid challenge?
50%
How many dogs presenting to ER with hypotension will respond to fluid bolus therapy?
60-65%
Why should fluid therapy be administered more carefully in septic patients?
Higher tendency to accumulate EVLW
What is a dynamic parameter? Give 7 examples for dynamic markers of fluid responsiveness
= measuring response to fluid bolus –> at least 2 timepoints
= goal is to determine where a patient is on the Frank Starling curve
= not a good marker of volume status
- CO
- Pulse pressure variation (PPV)
- Systolic pressure variation (SPV)
- Stroke volume variation (SVV)
- Plethysmographic variability index (PVI)
- Dynamic CVC Index
- caridac POCUS
