-
What 3 things affect stroke volume (not CO or HR)
- Preload
- Afterload
- Contractility
-
What is the degree of ventricular stretch before the next contraction
preload
-
What impacts preload
volume present in ventricles at end of diastole, vasoconstriction
-
What is the amount of resistance the ventricles must overcome to deliver the stroke volume into receiving vasculature
Afterload
-
What impacts afterload (4 things)
- Arterial systemic tone
- Blood viscosity
- Flow patterns
- Valve competency
-
What is the strength of myocardial muscle fiber shortening during systole
Contractility
-
What affects contractility
preload
-
What system is a high pressure, low volume, high-resistant circuit responsible for delivering O2 and nutrients to the capillary system
arterial
-
How many liters are in blood? How much plasma makes up the blood
-
What are high capacity, low resistance vessels
veins
-
amount of blood pumped out of ventricle every minute
CO
-
What does CVP measure?
Pressure created by volume of blood in right side of heart
-
What is the amount of blood ejected from the ventricle with each contraction? What is normal?
Stroke volume
-
resistance that the left ventricle must overcome to eject a volume of blood
SVR
-
What happens to CO if SVR increases
decreases
-
resistance that the right ventricle must overcome to eject a volume of blood
PVR
-
What is JVP an indirect measure of
CVP
-
What is considered an elevated JVP
>3 cm above angle of louis
-
What are the 5 components of the hemodynamic monitoring system
- invasive catheter
- high-pressure non-compliant tubing
- Transducer (stopcocks)
- Pressurized flush system
- bedside monitoring system
-
Where is Central venous catheter most commonly placed
subclavian or internal jugular
-
What translates intravascular pressure changes into waveforms andnumerical data
transducer
-
What are 4 major components for validating accuracy of hemodynamic monitoring systems
- Patient positioning
- Zeroing the transducer
- Leveling the air-fluid interface (zero stopcock to phlebostatic axis)
- Assessing dynamic responsiveness (square wave test)
-
Where should transducer system be positioned when zeroing stopcock
phlebostatic axis
-
Where is phlebostatic axis located
4th intercostal space, midway point of the anterior-posterior diameter of the chest wall
-
What can an overdamped system indicate when doing square wave test
systolic pressure falsely low and diastolic pressure falsely high
-
What can an underdamped system indicate when doing square wave test
falsely high systolic and low diastolic
-
Causes of overdamped system during dynamic response test
- Blood clots/air bubbles
- Loose connections
- kink in tubing
- compliant tubing
-
Causes of underdamped system during dynamic response test
- Excessive tubing length
- Small bore tubing
- possible artifact
-
What site has the highest rate of complications (pneumothorax and phrenic nerve damage) when picked for the measurement of CVP
subclavian
-
How often should tubing and flush bag be changed during hemodynamic monitoring to prevent infection of CRBSI
72-96 hrs
-
What pressure of flush solution should be used during hemodynamic monitoring
300
-
What are some indications or arterial pressure monitoring
- risk of compromised tissue perfusion & volume status
- frequent labs
- hypo/HTN
-
Whats the site of choice for arterial pressure monitoring
arterial
-
What should be done EVERY time before cannulation of radial artery
allens test
-
What is the most accurate method of obtaining systemic blood pressure
arterial pressure monitoring
-
How do you do the Allen's test
- make tight fist
- occlude artery for 10 sec
- should blanch within 5 sec after release while hand is open
-
What is the reference point between the systolic and diastolic phases of the cardiac system
dicrotic notch (aortic valve close, beginning of diastole)
-
4 major complications of arterial pressure monitoring
- thrombosis
- embolus
- infection
- blood loss
-
What should be suspected if noninvasive BP is higher than invasive BP
- equipment malfunction
- technical error
-
Name interventions for pt with intrarterial catheter
- assess q 2 hrs
- keep wrist neutral
- pressure on insertion site after removal (5 min if radial)
- NO MEDICATIONS VIA ARTERIAL LINE
-
What measurement assesses the preload of the right side of the heart
RAP
-
What does it mean if RAP and SI are both low? High?
- Low: hypovolemia
- High: RV dysfunction
-
When should RAP be measured
end expiration and end of ventricle diastole
-
What causes high RAP
- hypervolemia
- severe vasoconstriction
- mechanical ventilation
-
What causes low RAP
- hypovolemia
- vasodilation
- sepsis
-
What does PAOP tell us
function of Left side of heart
-
pt positioning for PA catheter insertion
trendelendburg or blanket roll places between pt's should blades
-
how do u measure PAOP
inflate balloon no more than 1.5 mL for no longer than 8-10 sec
-
causes of decreased preload
- hemorrhage
- hypovolemia
- vasodilation
- fluid shifts outside intravascular space
-
causes of increased afterload
- vasoconstriction
- increased blood viscosity
-
causes of decreased contractility
- MI or ischemia
- HF
- Cardiomyopathy
- cardiogenic shock
- cardiac tamponade
-
causes of increased preload
- fluid resuscitation
- alteration in ventricular compliance
-
causes of decreased afterload
- Vasodilation in sepsis
- Decreased blood viscosity (anemia)
- Increased contractility
- hypermetabolic states
- medication therapy
-
4 causes of high SVO2
- shunting
- increased affinity of hgb for O2
- Increased distance between capillaries and cells
- Inability to take up/use O2 (sepsis)
-
3 components of respiratory system
-
Which bronchus is shorter, wider and straighter
right mainstem
-
-
Top of each lung called? lower part?
-
What pleura covers the lung surfaces
visceral
-
what pleura covers internal surface of thoracic cage
parietal
-
normal pressure of pleural space
-5
-
Describe what occurs during inspiration
- diaphragm lowers and flattens
- intercostal muscles contract
- chest wall lifts up and out
- intrapleural and intraalveolar negative
-
Describe what occurs during expiration
- Diaphragm and intercostal muscles relax
- Lungs recoil
- Positive intraalveolar pressure
-
4 steps of gas exchange
- ventilation
- diffusion at pulmonary capillary
- Perfusion
- Diffusion to cells
-
Movement of gases in and out of alveoli
ventilation
-
Where is oxygen pressure higher? CO2?
- O2: alveoli
- CO2: Capillaries
-
Where is oxygenated blood transported from the pulmonary capillary
to the left side of heart from pulmonary vein
-
Where is Carbon dioxide transported
to right side of heart via vena cava into pulmonary capillaries to diffuse into alveoli for elimination
-
What regulates rate, rhythm, and depth of ventilation
medulla and pons
-
What happens when CO2 is high or O2 is low
chemoreceptors are stimulated and send message to medulla
-
In normal lung function, what stimulates respirations? In people with chronic obstructive lung disease?
- high levels of CO2
- Hypoxemia
-
What is lung compliance
stretchability of lung and chest wall
-
What refers to how easily the lungs are stretched when the respiratory muscles work and expand the thoracic cavity
distendability
-
What conditions lead to low lung compliance
- pulmonary fibrosis
- ARDS
- Pulmonary edema
- Obesity
- mechanical ventilation
-
How does emphysema cause lungs to lose their elasticity, thereby increasing compliance
destruction of lung tissue and enlarged air spaces
-
What two things does dynamic compliance measure
- lung compliance
- airway resistance to gas flow
-
3 things that affect airway resistance
- airway length (long-increased)
- airway diameter (narrow-increased)
- flow rate of gases (broncoconstriction, mucus, edema-increased)
-
volume of normal breathing (Vt)
Tidal volume
-
amount of remaining air in the lungs after maximal expiration
Residual volume
-
volume of gas that can be inspired at normal resting expiration
Inspiratory capacity
-
Maximal volume of gas that can be forcefully expired after maximum inspiration
Vital capacity
-
During inspiration, what can cause asymmetrical excursion of chest
unilateral ventilation
-
What can a tracheal shift indicate
tension pneumothorax
-
What is a cyanosis a late sign of
hypoxemia
-
Normal inspiratory/expiratory ratio
1:2
-
2 disease processes Cheynes Stokes is seen
-
deep, increasingly shallow respirations followed by progressive periods of apnea (last at least 20 sec)
Cheyne-Stokes
-
What is cluster breathing in which there are variations in depth and periods of apnea?
Biots
-
Where do u see Biots respirations
Brainstem injury
-
deep, regular, and rapid respirations
Kussmaul
-
Where is kussmaul breathing seen
DKA
-
Gasping inspirations followed by short, ineffective expirations
Apneustic
-
Where do u see Apneustic respirations
lesions to the pons
-
presence of air beneath skin surface that has escaped from the airway of lungs
Subcutaneous crepitus/emphysema
-
5 sounds of audible percussion from pt chest
- resonance (normal)
- dullness (consolidation)
- flatness (lung collapse)
- hyperrosonance (emphysema)
- tympany (pneumothorax)
-
bubbling sounds from air bubbling through fluid or mucus
crackles
-
possible indications from crackles
- bronchitis
- pneumonia
- atelectasis
-
sonorous, rattling sound caused by air movement through excessive mucus, fluid, inflamed airway
rhonchi
-
causes of rhonchi
- pneumonia
- bronchitis
- pulmonary edema
-
whistling, musical sound caused by narrowing of the airway
wheezes
-
causes of wheezes
- Bronchospasms
- Partial obstruction
- Inflammation
- Stenosis
-
high pitched crowing sound caused by total constriction of larynx or trachea
stridor
-
causes of stridor
- laryngeal edema
- choking
- epiglottitis
-
coarse, grating sound caused by inflamed pleura rubbing against each other
pleural friction rub
-
causes of pleural friction rub
- Pleuritis
- Pneumonia
- TB
- Chest tube insertion
- Pulmonary infarction
-
How to tell the difference between pleural friction rub and pericardial friction rub
hold breath, if it goes away it is pleural
-
Partially compensated resp acid
-
Partially compensated resp alka
-
Fully compensated resp acid
-
Fully compensated resp alka
-
Partially compensated met alka
-
Fully compensated met alka
-
Partially compensated met acid
-
fully compensated met acid
-
combined resp and met acidosis
-
combined resp and met alka
-
BE of Met acidosis and Resp alkalosis
-2
-
BE or met alka and resp acid
+2
-
What is critical zone of oxyhemoglobin dissociation curve
PaO2 <60
-
oxy hgb right shift
<hgb affinity to O2, O2 more readily released to tissues
-
causes of oxy hgb right shift
- acidemia
- inc temp
- anemia
- chronic hypoxemia
- low CO
-
What is PaO2 when there is a right oxy hgb shift
higher than expected
-
oxy hgb left shift
hgb affinity for o2 increases and hgb clings to o2
-
causes of oxy hgb left shift
- alkalemia
- dec temp
- high altitude
- carbon monoxide poisoning
- Administration of stored bank blood
- Septic shock
- hypophosphatemia
-
PaO2 when there is left oxy hgb shift
lower (<92, hypoxemia)
-
-
causes of resp alkalosis
- Hyperventilation
- Pain, fever
- Mechanical ventilation
-
Causes of Metabolic acidosis r/t increased acid
- DKA
- Renal Failure
- Lactic Acid
-
Causes of Metabolic acidosis r/t loss of base
diarrhea
-
causes of metabolic alkalosis r/t gain of base
-
causes of meta alka r/t loss of acids
- vomit
- NG suction
- <K
- diuretics
-
Most important buffering system
bicarb
-
How long does it take for renal system to secrete bicarb enough to compensate
2 days
-
4 critical ABG lab values
- PaO2 <60
- PaCO2 >50
- pH <7.25 or >7.60
- SaO2 <90
-
What can affect accuracy of SpO2
- artifact
- limb ischemia
- inflated BP cuff
- sun/fluorescent light
- nail polish
-
Name low-flow O2 systems
- nasal cannula
- simple face mask
- partial rebreather
- non-rebreather
-
Name high-flow O2 systems
- venturi
- high flow nasal cannula
- air entrainment
-
when is humidification recommended for pts receiving O2 flow
>4L/min
-
Two types of ARF classifications
-
What is considered hypercapnic ventilatory failure
pH <7.30 and PaCO2 >50
-
5 generally accepted mechanisms of failure to oxygenate (<PaO2) creating a state of hypoxemia
- hypoventilation
- intrapulmonary shunting
- Ventilation-Perfusion mismatch
- diffusion defect
- decreased barometric pressure
-
What is intrapulmonary shunting
When a large amount of blood bypasses gas exchange to the left side of the heart
-
4 things that can cause shunting
- septal defects
- pneumonia
- atelectasis
- pulmonary edema
-
What is the most common cause of hypoxemia in respiratory failure
V/Q mismatch
-
6 barriers to diffusion of O2
- surfactant
- alveolar epithelium
- interstitial fluid
- capillary endothelium
- plasma
- RBC membrane
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