CCU: Monitoring Flashcards
Dehydration is a deficit in
extracellular fluid
What are the 6 perfusion parameters that are important to monitor for shock
1) Heart Rate
2) Pulse quality
3) Mucous membrane color
4) Capillary refill time
5) Extremities temperature
6) Mentation
T/F: compensated shock has normal blood pressure
true- blood pressure is highly preserved by the compensatory response
What are the indications for measuring arterial blood pressure
1) Routine monitoring
2) Anesthetized patients
3) Classification of compensated / decompensated shock
4) Monitoring resuscitation
What is normal blood pressure
Systolic: 120-140mmHg
Diastolic: 70-90mmHg
Mean: 90-110mmHg
140/80 with a mean of 100 *
What are the limitations of arterial blood pressure measurements
-Dont indicated if patient is in shock or not
-Not a measure of perfusion
-Insensitive- highly preserved by compensatory response. Arterial BP is the last thing to go
-Variability in measurement, especially indirect BP: obtain repeated 3-5 measurements and average
-Can be affected by other factors (pain, stress, etc)
*Must correlate findings to physical exam/clinical picture
How should you obtain a reliable blood pressure when indirect BP often has variability
obtain repeated 3-5 measurements and average
What is the gold standard for arterial blood pressure measurement
direct
What are the pros of arterial blood pressure
Systolic, diastolic and mean pressure
arterial waveform for further analysis
continuous monitoring allows close monitoring of changes
What are the cons of direct arterial blood pressure measurement
-Requires placement of arterial catheter
-Invasive, technically challenging
-Requires monitor and pressure transducer for measurements
-Pressure tracings can be distorted: clots, kinks, inappropriate tubing
What are the two main devices of indirect blood pressure measurement
1) Doppler with Sphygmomanometer
2) Oscillometry
noninvasive
readily invasive
In most studies does Osc vs Doppler vs Direct perform better in dogs and is more accurate
Oscillometry
Pros and Cons of Doppler
Pros:
-Inexpensive
-Readily available
-Auditory signal generated
-Better in cats
Cons:
-Less accurate in dogs
-Measures systolic BP only
-May not actually measure SBP
-Requires patient manipulation
-People/time consuming
-Operator dependency
-Auditory signal generated
Pros and Cons of Oscillometric
Pros
-Accurate
-Readily available
-Systolic, diastolic and mean BP
-Measures HR
-Not operator dependent
-Hands off measurement
-Automatically cycle for repeated measurements
Cons:
-More expensive
-May be affected by motion, variable heart rate, and pulse deficits
-Black box effect
Dopper measures ___________
Oscillometric measures_______
Doppler: Systolic BP only
Oscillometric: Systolic, diastolic, and mean BP
What values define hypotension
MBP <60-65mmHg
SBP <90mmHg
Hypotension is more commonly seen in
ER/Urgent care due to decompensated shock secondary to severe dehydration, acute hemorrhage, trauma, sepsis
T/F: blood pressure is necessary to diagnose shock
False- it is not necessary but it does help to classify it between compensated and decompensated
What aspect of blood pressure do mot ECC clinicians worry about most
CPP = MBP - ICP
depends on the MBP
What values define hypertension
MAP> 160mmHg or SBP >200mmHg
Hypertension might be secondary to
1) Pain, stress = physiological response
2) cardiac disease
3) renal disease
4) Cushing’s disease
5) Pheochromocytoma
6) Toxin injection (ie chocolate)
How do you treat hypertension
target the cause and/or vasodilators, ACE-inhibitors
What are the indications for measuring ECG
-Unstable patients- heart rate is an early indicator of CV instability
-Presence of brady or tachyarrhthmias
-pulse deficits
-guide shock resuscitation
-guide anti-arrhthmic therapy
How do you do apply ECG
3 leads (LF,RF, LH)
most commonly interpreted in lead II (RF, LH)
represents the summed electrical activity in the heart
Electrocardiogram (ECG)
produced with anaerobic metabolism
marker for perfusion, O2 delivery or utilization
lactate
How is lactate measured
blood gas analyzer or hand-held lactometer
What are the indicators for measuring lactate
-Patients with evident or suspected hypoperfusion (objective assessment, guide therapy)
-Can be served as a guide for fluid therapy/resuscitation
-Help decide need for RBC transfusion
Does lactate has a prognostic marker or severity of disease
failure to improve may have prognostic value
lactate clearance is a better prognosis marker
What are the limitations of lactate
1) May be high with altered cellular utilization of oxygen
2) Cellular energy demand exceeds a normal supply (seizures, physical exertion, etc)
3) Can reflect abnormalities with clearance or overproduction (Type B hyperlactemia, liver disease, drugs, sepsis, etc)
What can abdominal POCUS tell you
1) Caudal Vena Cava Collapsibility (Subxyphoid or hepatic or intercostal view)
2) CVC:Ao ratio (Paralumbar view)
What can cardiac POCUS tell you
1) Detection of pericardial effusion
2) Subjective assessment of systolic function = contractility
3) Subjective assessment of cardiac underfilling or overloading
What does a flat Caudal Vena Cava on POCUS mean
Hypovolemic
What does a fat Caudal Vena Cava on POCUS mean
Fluid overloaded or well fluid
CVC diameter is larger in inspiration or expiration
expiration
What is the normal compressibility of the CVC
30-50%
What does increased CVC compressibility on inspiration mean
Hypovolemia
The CVC collapses during inspiration or expiration
Inspiration
What does decreased CVC compressibility on inspiration mean
Hypervolemia
Why does the aortic diameter not change in intravascular volume
because the aorta has a thicker and more rigid vessel wall than the CVC
-NOT affected by the respiratory cycle
Normal CVC:Ao ratio is
1:1
What is a better marker of hypovolemia than CVC measurement
CVC: Ao ratio
not affected by breathing cycle, but could be affected by changes in abdominal pressure
Static marker
What is the preferred view for cardiac POCUS
right parasternal short and long axis
What is evaluated when doing cardiac POCUS
-Subjective/objective assessment of cardiac contractility
-Left ventricle internal diameter in diastole (LVIDd)
-Ventricular wall thickness/flattening
-Atrial lumen size and LA:Ao rato
Normal LVID depends on weight
What does an increased left ventricle internal diameter in diastole mean
patient might be hypervolemic
a measurement that used pressure to assess volume status
based on the notion that CVP=RAP=RVEDV
considerable debate as to accuracy/utility
Central Venous Pressure
What factors affect central venous pressure relationship to volume
1) Venous Return
2) Venomotor tone
3) Intrapleural pressure
4) Right atrium function
5) Cardiac output
considerable debate as to accuracy/utility
-confounding factors, technical issues, repeatability
Methods to assess cardiac output
1) PAC thermodilution- gold standard for assessing CO via placement of Swan-Ganz catheter, injection of cold saline from proximal port, temperature measured at tip in PA, speed of temperature depends on CO
2) Transthoracic Doppler- noninvasive CO monitoring, doppler ultrasound probe to detect aortic blood flow, corss-sectional area of vessel predicts stroke volume (SVxHR=CO)
noninvasive CO monitoring, doppler ultrasound probe to detect aortic blood flow, cross-sectional area of vessel predicts stroke volume (SVxHR=CO)
Transthoracic Doppler (USCOM)
gold standard for assessing CO via placement of Swan-Ganz catheter, injection of cold saline from proximal port, temperature measured at tip in PA, speed of temperature depends on CO
PAC thermodilution
What are the indications to get PCV and total proteins
-Abnormal (pale, red, yellow) mucous membranes
-Shock (investigating cause)
-Fluid balance
-Sick animaal
Anemia (regen or non-regen) or polycythemia vera
PCV =
PCV= Hct= 3xHb
When getting PCV and total proteins, what else should you assess
serum color
With blood loss, both PCV and TP are decreased but why is PCV >TP
because of splenic contraction
With dehydration, will both PCV and TP be increased or decreased
increased
If you have increased albumin, its because _______ while increased total protein is likely _________
albumin: dehydration
TP: hyperglobulinemia
Why should we not use the term “total solids”
because the total protein level is estimated by refraction produced by combined plasma concentration of its solutes- aka the total solids
Protein does not equal oncotic pressure
What are the indications for measuring blood glucose
-minimum data base
-shock
-known diabetic patient
-seizuring puppy/kitten
-monitoring hypo/hyperG
Where you do sample for a blood gluocse measurement
vein
capillary (ear, paw pads, elbow callus and outer lip)
What should you consider when measuring blood glucose
important to use animal validated for small animals
determine whole BG concentrations so needs erythrocytes (humans contain different amount of glucose compared to animals in RBCS) so use species specific code (GlucoPet, AlphaTrack 2)
Why should you never use the term dyspnea
because it is a sensation and patients are unable to verbalize they are in respiratory distress
say respiratory distress instead
ability of CO2 to exit the body
ventilation
decreased tissue perfusion of O2
hypoxia and perfusion
decreased of PaO2
hypoxemia
physical examination of respiratory distress is
increased respiratory rate and effort
What constitutes an animal with increased respiratory effort
orthopneic posture
-elbow abduction
-neck extension
-open mouth breathing
-nasal flaring *
-cyanosis
When a patient is in respiratory distress, what should you start with
Pulse oximetry
In regards to respiration, what should you be looking for on a physical exam
1) Resp rate
2) Resp Efforts (Elbow abduction, neck extension, open mouth breathing, nasal flaring, cyanosis)
3) Respiratory patterns
4) Audible breathing sounds
5) Use of stethoscope for respiratory sounds
Used as a non invasive surrogate for PaO2 but not directly related
Pulse oximetry
Pulse oximetry is accurate at
+/- 2/4 percentage points which may be significant at the steeper part of the curve
When is pulse oximetry less accurate
SaO2 <85% but you still know the patient is hypoxemic
What is normal pulse oximetry
> 98%
SaO2 of 95% = PaO2 of
80mmHg
SaO2 of 90% = PaO2 of
60mmHg
How can pulse oximetry be used as threshold for client communication
97%-100%: normal, look for look alikes
95-95%: may be able to be treated as outpatient
90-95%: will usually/probably need to be hospitalized
<90% may need to be mechanically ventilated
What are the 5 causes of hypoxemia
1) Low partial pressure of PiO2 (altitude, empty O2 tank, faulty anesthetic equipment, housefire)
2) Hypoventiliation
3) Low V/Q
4) No V/Q (shunt) - pulmonary or anatomic- no ventilation to perfused lung units
5) Diffusion Impairment - pulmonary fibrosis
What might cause low PiO2 leading to hypoxemia
altitude
empty O2 tank
fault anesthetic equipment
House fire
what might cause a diffusion impairment leading to hypoxemia
pulmonary fibrosis
What are the 8 places where respiratory distress can arise from
1) Upper
2) Lower
3) Parenchyma (water, blood, pus, tissue)
4) Chest wall- including muscular fatigue and neurologic
5) Diaphragm/Abdomen- including muscular fatigue and neurologic
6) Pleural space - air, fluid, tissue
7) Vascular- PTE
8) look alikes- non respiratory causes: anemia, shock, pain sepsis
What are some non-respiratory causes of respiratory distress
anemia
shock
stress
pain
sepsis
occurs due to high PCO2 where the CO2 takes up space in the alveoli and contributes to hypoxemia
Hypoventilation
T/F: PvO2 is a marker of oxygenation
False
difference between PAO2 and PaO2
A-a gradient
the A-a gradient should be _________ in an animal with normal lungs, no abnormal anatomic shunts, breathing 21% oxygen at sea level
<10 mmHg
What is the basis of defining hypoxemia
PaO2
What do you need to assess hypoxemia
arterial blood gas with a known FiO2
the ratio of PaO2 to FiO2 with FiO2 expressed as a decimal (400-500)
P/F ratio
You should only use the P/F ration when there is
stable PCO2 and variable FiO2
influenced by PCO2
What decreases P/F ratio
decreased lung function - useful to assess pulmonary function
How do you calculate A-a gradient
{[(Pb-Ph20)x FiO2] - PaCO2 (1/RQ)} - PaO2
simplied if room air at sealevel
A-a = 150-1.1xPaCO2 - PaO2
The FiO2 should be about
400-500
What is the simplified A-a gradient if on room air at sea level
A-a = 150-1.1xPaCO2 - PaO2
Why is PaCO2 slightly lower than at sea level
due to compensation for the low PaO2 (to maintain normoxia)
Normal PaCO2 in CO is 30-40mmHg instead of 35-45 mmHg at sea level
What allows the movement of air in and out of the respiratory system to properly ventilate
1) Diaphragm: main muscle of inspiration- phrenic nerve (C3-C5)
2) Rib cage and related msucles
3) Abdominal muscles- forced expiration
4) Accessory muscles- neck, nares
what innervates the diaphragm and allows it to be the main muscle of inspiration
Phrenic nerve (C3-C5)
What are the indications to use a capnometry/ capnography
-Breath by breath surrogate for PaCO2/ PVCO2
-ROSC in CPR
What is a normal caponmetry reading
PETCO2 = 30-40mmHg
usually 5mmHg difference between
PvCO2 > PaCO2 > PETCO2
How much does PvCO2, PaCO2, and PETCO2 differ
usually a 5mmHg difference
What is the limitation of capnometry and canopgraphy
needs the patient to be intubated
What are the phases of capnography
I: inspiratory baseline
II: Expiratory upstroke
III: Expiratory plateau
EtCO2- end expiration
IV: Expiratory Downstroke
What is the alpha angle of the capnograph
the angle between phase II (expiratory upstroke) and Phase III (expiratory plateau)
allows you to assess ventilation/perfusion of the lung
V/Q mismatches will have an alpha angle greater than 90 degrees
What alpha angle tells you there is a V/Q mismatch
when it is greater than 90 degrees
What is the beta angle in the capnograph
the angle between the end expiration and the expiratory downstroke
used to assess rebreathing, if rebreathing occurs the angle is greater than 90 degrees
What beta angle tells you that rebreathing is occuring
if the angle is greater than 90 degrees
You perform a venous blood gas on a dog. the PvCO2 is 62mmHg. Is the dog hypo or hyperventilating
Hypoventilation - CO2 is high
You perform a venous blood gas on a dog. the PvCO2 is 62mmHg. Is this dog most likely acidemic or alkalemic
Acidemic
You perform a venous blood gas on a dog. the PvCO2 is 62mmHg. What is most likely cause of ventilation disorder
Upper-Airway Obstruction
What are the 3 main reasons for respiratory acidosis
1) Brain doesnt work
2) Muscle doesnt work
3) Upper-Airway obstruction
You should calculate the anion gap if there is
a metabolic acidosis
Decreased pH and increased PCO2
Respiratory acidosis
Increased pH and decreased pCO2
Respiratory alkalosis
Decrease pH and HCO3
metabolic acidosis- do an anion gap
Increased pH and HCO3
metabolic alkalosis
What is the rule of 4s for normal blood gas values
pH= 7.4 +/- 0.04
HCO3= 24 +/- 4
base exess/deficit= 0 +/- 4
PCO2= 40 +/- 4
Anion gap = 14 +/- 4
Na = 144 +/- 4
K= 4 +/- 0.4
loss of ECF = ______ while loss of ICF=_______
ECF: dehydration
ICF: free water loss
What factors can you use to evaluate fluid balance
1) Physical Exam
2) Body weight
3) Urine specific gravity
4) Urine output
5) PCV-TP
Hydrated/volume repleted animals have a USG of
1.008-1.012 (isostenuric)
if unreliable with impaired concentrating ability the kidney disease or renal injury
What should urine output be? Used as an indicator of renal perfusion/volume status
minimum of 1-2ml/kg/hr
*may not be indicative of perfusion in other tissues
Increased albumin has one rule out which is
dehydration … but it can be influenced by anemia, protein losss, etc.
If both PCV-TP are elevated then
its usually a marker of dehydration/hemoconcentration
Causes of hyperthermia
1) Fever (pyrexia)
-Infectious
-Inflammatory
-Neoplasia
-Drug induced (opioids, ketamine in cats)
2) Exposure/failure to dissipate
-airway obstruction
-external heat source
What are causes of hypothermia
-Shock
-Anesthesia
-Exposure (ie cold)
-Renal failure
-Hypothyroidism
What might cause hyperkalemia
urinary obstruction
AKI
Addisons
reperfusion injury
What electrolyte disturbance is common in ICU, especially on IV fluids
Hypokalemia- secondary to diuresis and/or decreased intake
What is the main goal of focused ultrasound
find free fluid
What are the 4 quadrants of abdominal POCUS
1) SubXyphoid
-Liver and between liver lobes
-Gallbladder
-Pleural/pericardial space thru diaphragm
-Caudal vena cava distension
2) Bladder- and neck, beware of colon shadow
3) Right kidney- most ocmmon fluid location
4) Left kidney- spleen
What can you see in the sub-xyphoid view when doing abdominal POCUS
-Liver and between liver lobes
-Gallbladder
-Pleural/pericardial space thru diaphragm
-Caudal vena cava distension
What are the indications for focused abdominal US
trauma
shock
collapse
acute abdomen
non-invasive
rapid
repeatable
What is the primary goal of thoracic ultrasound **
best to rule out pneumothorax
When doing thoracic POC ultrasounds, what is the best view to ruling out pneumothorax
caudo-dorsal- highest point on the thoracic wall
When doing thoracic POC ultrasounds, what does the caudo-dorsal view assess
rules out pneumothorax
When doing thoracic POC ultrasounds, what does the cranioventral view assess
the cardiac site
1) Pleural or pericardic fluid
-Subjective volume assessment
2) LA and Ao ratio quick peak
3) Check the heart and pericardial space
When doing thoracic POC ultrasounds, what does the subxiphoid view assess
may be superior for the detection of pericardial (and pleural effusion) fluid
What can you see when doing focused thoracic ultrasounds
Gator sign
Glide sign
A-line
Lack of glide signs on thoracic POCUS indicate
pneumothorax
What do shred/Clines on thoracic POCUS indicate
consolidation of lung tissue
What do B-lines indicate
wet lungs
How do you calculate the anion gap
AG = UA - UC = (Na+K) - (Cl + HCO3)
Normal in dogs = 18 +/-6 and 20 +/-7 cats
