Jamie Wood
RSPT 233/Haines
Mechanical Ventilation
10/18/2014
Mechanical Ventilation Outline/Study Guide
Weeks 1-7
I Initiation, Modes/Settings, Manipulation, Calculations, Weaning, & Troubleshooting
When do we Initiate mechanical ventilation?:
o Respiratory Distress Type 1: Hypoxemia without hypercapnea
o Respiratory Distress Type 2: Hypoxemia with hypercapnea
Parameters for mechanical ventilation:
o MIP -20-0 cmH2O
o MEP <40 cmH20
o VC <10-15 cmH2O
o Vt <5 ml/kg
o RR >35 BPM
o FEV1<10 ml/kg
o PEFR 75-100 L/m
o VD/VT <7.25 cmH20
o PaCO2 >55 cmH2O
o PaO2 < 70 on FiO2 of 60%
o pH <7.25 mEq/L
o A-a >450 cmH2O
o P/F <200 cmH2O
Setting:
o 5-7 mg/kg for Restrictive Lungs and 8-12 or 8-10 lungs without a respiratory history
o AC-Volume Control: Initial Vent set-up without history:
o Tidal volume : based on IBW and restrictive or non-restrictive lungs
o Rate 8-12 BPM
o FiO2 40-60%
o PEEP: 5
o Initiated once FiO2 of 60 % in reached
o Flow 40-60 LMP
o Sensitivity 0.5-3
o 1:E 1:2
o Apnea 20 sec
o Decelerating or constant wave form
AC-Pressure Control:
o Peak Limit pressure: 15-25 cmH2O
o Rate 8-12 BPM
o FiO2 40-60%
o PEEP 5 cmH2O
o Initiated once FiO2 of 60 % in reached
1
o Rise-time 50%
o I-Time: 0.8-1.2
o Sensitivity 0.5-3
o Apnea 20 sec
o Decelerating waveform
CPAP:
o PS 10-12 cmH2O
o Sensitivity 0.5-3
o Apnea 20 sec
SIMV:
o PS 10-12 cmH20
o Sensitivity 0.5-3
o Apnea 20 sec
PRVC:
o Targeted Vt based on IBW and restrictive or non-restrictive lungs
o Pressure Limit 15-25 cmH2O
o Rate 8-12
o FiO2 40-60%
o Rise-time 50%
o PEEP 5
o Sensitivity 0.5-3
Alarms:
o High pressure/low pressure: 10/5
o High rate/low rate: 10:5
o High flow/low flow: 2L/2L
o Vt: 200-100/100-150
Incremental Changes:
o Vt: 50-100
o Rate: 2-6
o PEEP 1-2 cmH2O
o Flow: 5-10 L
o FiO2: 5-15%
o Pressure: 2-5 cmH2O
Manipulations:
o Respiratory & Metabolic Acidosis: increase Vt first, then rate can be increased only if patient
isn’t breathing over the backup rate.
o Respiratory & Metabolic Alkalosis: Decrease rate first, then decrease Vt.
o Hyperoxygenation: decrease FiO2 or PEEP
o Hypoxygenation: increase FiO2 or PEEP
Weaning:
When is a patient ready for weaning?
o Their underlying condition has been resolved
o They are hemodynamically stable
o Diagnostics: Labs, CXR and ABGs to determine issue is resolved
o Check to see if the patient on sedation
o Does the patient have the drive to breathe
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o MIP: -20 cmH2O is the lowest acceptable
o MEP: <50 cmH20 ?
o VC: >10 cmH2O
o RSBI: <105 or <100 being ideal/normal 50-100
Spontaneous Breathing Trials
CPAP:
o Pressure support 5-10 cmH2O
o FiO2
o Flow ?
o Sensitivity
ATC (automatic tube compensation):
o ATC delivers the exact amount of pressure required to overcome the resistance imposed by
the ETT and reduces WOB
o Provides variable pressure and variable inspiratory flow compensation
o ATC increased pressure at the upper airway by the amount equal to the continuous calculated
pressure drop across the ETT during inspiration
SIMV:
o Pressure Support
o FiO2
o Flow
o Sensitivity
Trouble Shooting
High rate/High Ve can be caused by
o Pain, agitation, anxiety and fever : suggest possible sedation or other pain/fever medications
o Low Vts: increase Vt or flow
o Metabolic acidosis: change mode
Low Rate
o Over-sedation
o Compensated metabolic alkalosis
o Being over-ventilated with high Vte
o Atrophy of the diaphragm
o Neuromuscular impairment
High PIP
o Obstruction in the airway
o Secretions
o Bronchospasms
o Patient is agitated
o Kinked tubing, biting the tube
o Agitation
o Patient coughing
Low PIP/Low Vte:
o
o
o
o
Look for obvious leaks
Does the patient have a chest tube
Did the patient self extubate
Check the integrity of the cuff
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o Is the patient on spontaneous modes without PSV or support
II Difference between static and dynamic compliance and do they relate to positive
pressure ventilation:
o Dynamic compliance is the movement of airflow through the upper airway. Dynamic
compliance during positive pressure ventilation is related to resistance that airflow must
overcome to move through the airway and obstruction that causes resistance to that airflow.
o Static compliance is the measure of the volume of air not moving that the lungs can accept.
Static compliance with positive pressure ventilation is measured to determine the volume of
air that the lungs can accept and compliance of the lungs.
Elastic and frictional resistance:
o Elastic resistance is: The stiffening of the elastic system of the chest wall that produces an
increase in PIP. PIP contributes to a decrease in compliance in the lungs. Decreased
compliance in the lungs results in a decrease ability of the lungs to accept a desired volume
to maintain adequate gas exchange and therefore oxygenation.
o Frictional resistance: is simply airway resistance (Raw), which is opposition of the airways
to flow and the tissues being displaced. The Opposition by the airways to flow results from
excessive secretions, bronchospasms, and increase PIP, which inhibits the total gas filling
that normally takes place in the alveoli, resulting in a decrease in gas exchange.
III Effective Weaning Techniques: SBT: CPAP/SIMV, T-Piece and ATC
CPAP/SIMV:
o Progressively reduce the patients mandatory rate by 1-2 BPM at a pace that matches
improvement of the patient at a RR of >8 BPM
o Pressure support of 5-10 cmH20 for ,< 2-4 hours is provided to help unload the patients
spontaneous breath and reduce the patients WOB against the vent, circuit and ETT.
o If no lung disorders use 30 minute intervals instead
o PEEP of 3-5 is maintained to compensate for changes in the FRC resulting from breathing
through the ETT.
o Apnea settings allow for additional support if needed
T-Piece:
o Is initiated if patient is able to spontaneously breathe
o Patient is placed on a t-piece and off of vent support or places on CPAP, for increments if 510 minutes then place back on the vent for the duration of the hour. This is repeated once an
hour.
o Adjustments will continue until patient progressively reaches 30 minutes on and off of the
vent. The 30 minute duration off the vent then is increased by an hour and progressively
increased thereafter.
o Humidification with a large reservoir, connected to air/O2 blended gas source that provides
high flows of up to 10 L/min, at a desired FiO2 is connected to the t-piece.
o On the exhalation port a large bore tube is connected to provide a reservoir.
o If the patient remains stable for at least 2 hours, consider extubation
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o Advantage of using CPAP is the available alarms, apnea back up, and ability to monitor the
patients ventilation.
o If patient is stable after 2 hours consider extubation
PSV: Rate, timing and depth of breathing is determined by the patient:
o Level of Pressure support is typically based on the patient’s Raw while on CMV and is set
10cm H2O above the patient’s Raw.
o Normally PSV is set at 5-10 cmH2O for patient meeting weaning criteria
o Also used to establish the patients baseline rate and Vt.
o PSV is gradually reduced as long as spontaneous rate and Vt are maintained and no signs of
distress occur
Closed Loop Control Modes
ATC (automatic tube compensation):
o ATC delivers the exact amount of pressure required to overcome the resistance imposed by
the ETT and reduces WOB
o Provides variable pressure and variable inspiratory flow compensation
o ATC increased pressure at the upper airway by the amount equal to the continuous calculated
pressure drop across the ETT during inspiration
Volume targeted Pressure Support (VS):
o Patient triggered, pressure targeted, flow cycled
o Has not been shown to be an effective weaning method
o VS adjust pressure so that within a few breaths the Vt is met.
Mandatory Minute Ventilation (MMV):
o Monitors the set parameters and adjust accordingly
o Automatically adjusts support per the needs of the patient
o Maintains a consistent minute ventilation, by increasing support if the patients spontaneous
ventilation decreases
o MMV provides this support by adjusting the rate or Vt
o Problems associated with MMV: this mode can increase dead space in patient breathing rapid
and shallow
Adaptive Support Ventilation (ASV):
o ASV provides pressure limited breaths that target a pressure and rate
o ASV monitors pressure, flow, I-Time and E-Time, compliance, resistance and time constants
to ensure a constituent set Ve.
o Reduces WOB and auto-PEEP
Artificial Intelligence Systems (SmartCare/PS system:
o Monitors set volume, rate and ET-CO2 to adjust to the inspiratory pressure automatically to
maintain the patients zone of comfort
Clinical observations during weaning during the first 20 minutes:
o The patient’s HR may increase
o The patient may appear agitated
o RR may also increase
5
o Diaphoresis may result
IV APRV and its effectiveness in reducing mortality in ARDS patients
o APRV provides two levels of CPAP(PEEP)
o Used for patients that a hard to oxygenate (ARDS patients)
o Provides a distending pressure called high pressure during inhalation for 80-95% of the total
cycle time and a low distending pressure during exhalation for the remaining time.
o Protects against shear stress that is associated with ARDS (opening and closing of the
alveoli) to reduce progression of ARDS
Settings:
o
o
o
o
High-Pressure: 20-25 cmH2O
High-Time: 3-6 seconds
Low Pressure 0-5 cmH20
Low-Time 0.5-1 sec
How to increase PaO2
o
o
o
o
Increase High-P
Increase High-T
Decrease Low-P
To increase the Pressure gradient and allow for more volume delivery
How to decrease PaCO2
o
o
o
o
Decrease High-P
Increase Low-T
Increase Low-P
To decrease the pressure gradient to provide more diffusion
When to reduce support and how?:
o Once at a pressure of <20 cmH2O the high pressure can be reduced by increments of 2
cmH2O
o increase High-time by 0.5 increments
o Increase Low-P in increments of 2 cmH2O
o Once High-p and Low-P reach 15/15 then the mode is like CPAP on one continues pressure.
V High Frequency Ventilation (HFV):
o Used for patients with oxygenation issues
o Utilizes various gas distribution mechanisms
o Convection, Bulk Flow, Direct ventilation: Warming, filtering and humidification,
direct ventilation of the alveoli proximal to the tracheobronchial tree by bulk flow of
gas
o The Pendalluft effect: Asynchronous filling of slow and fast alveoli units
o Taylor dispersion: turbulence of gases in motion
o Asymmetry: gas moving in the opposite direction simultaneously
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o Cardiogenic mixing: the heart producing additional pressure that provides movement
and distribution of gases in the parenchymal
o Molecular diffusion: The distending pressure provided to the alveoli allows for
increase pressure gradients between the membrane, providing increased gas exchange
o Collateral ventilation: diffusion of gases throughout the collateral pathways of the
lugs (pores of Khan, the Canals of Lambert and Martin
Types of HFV
o
o
o
o
High frequency oscillatory ventilation
High frequency jet ventilation
High frequency percussive ventilation
High Frequency Flow Interruption
VI New Modes of Ventilation: sophistication and complexity (are they beneficial or do their
complexity decrease proper application:
PRVC: Pressure Regulated Volume Controlled: Provides a breath by breath analysis
Also called: APV, VTPC VC+: Used in AC and SIMV
o
o
o
o
o
o
o
o
Patient triggered, pressure targeted, flow cycled
Good for trending static compliance changes (patients entering into ARDS)
Pressure limit is set in the alarms at 35-40 cmH2O
The pressure will adjust per to achieve the targeted volume
If volume is met pressure remains the same
If volume is higher than targeted, pressure will decrease by 1-3 cmH2O
If volume is lower than targeted, pressure will increase by 1-3 cmH2O
Once the pressure comes within 5 cmH2O of the set pressure limit, the vent will dump the
volume
o The first breath is a test breath:
o 5-10 above PEEP
 Inspiratory hold to measure the static compliance
 The next 3 breaths pressure will increase to 75%
o Complications with this mode: not used for patients with irregular breathing patterns,
because they will not be able to achieve consistent volumes
APRV: Adapted Pressure Release Ventilation: 2 levels of CPAP (PEEP)
o Used for patients that a hard to oxygenate (ARDS patients)
o Provides a distending pressure called high pressure during inhalation for 80-95% of the total
cycle time and a low distending pressure during exhalation for the remaining time.
o Protects against shear stress that is associated with ARDS (opening and closing of the
alveoli) to reduce progression of ARDS
Settings:
o High-Pressure: 20-25 cmH2O
o High-Time: 3-6 seconds
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o Low Pressure 0-5 cmH20
o Low-Time 0.5-1 sec
How to increase PaO2
o
o
o
o
Increase High-P
Increase High-T
Decrease Low-P
To increase the Pressure gradient and allow for more volume delivery
How to decrease PaCO2
o
o
o
o
Decrease High-P
Increase Low-T
Increase Low-P
To decrease the pressure gradient to provide more diffusion
When to reduce support and how?:
o Once at a pressure of <20 cmH2O the high pressure can be reduced by increments of 2
cmH2O
o increase High-time by 0.5 increments
o Increase Low-P in increments of 2 cmH2O
o Once High-p and Low-P reach 15/15 then the mode is like CPAP on one continues pressure.
Adaptive Support Ventilation (ASV):
o ASV provides pressure limited breaths that target a pressure and rate
o ASV monitors pressure, flow, I-Time and E-Time, compliance, resistance and time constants
to ensure a constituent set Ve.
o Reduces WOB and auto-PEEP
HFOV: High frequency Oscillatory Ventilation
o Used for Adult and neonate with oxygenation issues (ARDS and patients predisposed to
Shear Stress)
o Provides active inhalations and exhalations
Settings:
o PEEP/MAP pressure is used as a baseline pressure: MAP normally 15-18 cmH2O
o Amplitude is generated around the PEEP and is maintains the inspiratory/expiratory volumes
generated by each frequency wave
o Frequency (Hz) = The Rate 1 Hz =60 Breaths/sec.
o 15 Hz= 900 BPS typically used for neonates
o 10 Hz= 600 BPS typically used for termed infants
o 8 Hz=480 BPS typically for children 6-10 kg
o 6 Hz= 360 BPS typically for children above 10 kg
o <5 Hz=300 BPS typically for adult patients
o IT% set normally at 33%
o I:E normally 1:2
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o Good chest and abdominal wiggle should be seen to be sure HFOV is working
MMV: Mandatory Minute Ventilation
o Monitors the set parameters and adjust accordingly
o Automatically adjusts support per the needs of the patient
o Maintains a consistent minute ventilation, by increasing support if the patients spontaneous
ventilation decreases
o MMV provides this support by adjusting the rate or Vt
o Problems associated with MMV: this mode can increase dead space in patient breathing rapid
and shallow
APV: Adaptive Pressure Ventilation
o
o
o
o
o
o
o
o
o
Used in AC and SIMV
Patient triggered, pressure targeted, flow cycled
Good for trending static compliance changes (patients entering into ARDS)
Pressure limit is set in the alarms at 35-40 cmH2O
The pressure will adjust per to achieve the targeted volume
If volume is met pressure remains the same
If volume is higher than targeted, pressure will decrease by 1-3 cmH2O
If volume is lower than targeted, pressure will increase by 1-3 cmH2O
Once the pressure comes within 5 cmH2O of the set pressure limit, the vent will dump the
volume
o The first breath is a test breath:
o 5-10 above PEEP
 Inspiratory hold to measure the static compliance
 The next 3 breaths pressure will increase to 75%
o Complications with this mode: not used for patients with irregular breathing patterns,
because they will not be able to achieve consistent volumes
ATC (automatic tube compensation):
o ATC delivers the exact amount of pressure required to overcome the resistance imposed by
the ETT and reduces WOB
o Provides variable pressure and variable inspiratory flow compensation
o ATC increased pressure at the upper airway by the amount equal to the continuous calculated
pressure drop across the ETT during inspiration
VS: Volume targeted Pressure Support
o Patient triggered, pressure targeted, flow cycled
o Has not been shown to be an effective weaning method
o VS provides pressure to allow the desired Vt to be reached in a few breaths
PAV: Proportional Assist Ventilation
o
o
o
o
Ideal for patient unable to maintain spontaneous ventilation
Provides, pressure, flow and volume assistants in relation to the patients effort
The greater the patient effort the more assistance provided
Capable of providing 5-95% of the support
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o
o
o
o
Used on ETT and Tracheostomy airway types
Expiratory sensitivity flow will cycle the next breath
The patient controls the TI, PIP, TE, and VT
Disadvantages: Auto-PEEP may develop with increased triggering effort, also a leak will
cause the machine to auto cycle.
VAPS: Volume Assured Pressure Support:
o
o
o
o
o
o
o
o
Helps to reduce the work of breathing, and maintain a minimum Vt and Ve
Settings: P-Limit, RR, Peak flow, PEEP, FiO2, Min. Ve.
If pressure is too high, then all breaths will be pressure limited
If Ve is not delivered, then the peak flow will maintain the volume until the volume limit is
reached
Once the Vt or more is delivered then the breath will end
The Vt set is the minimum that the patient will receive
The set pressure is the minimum of what the patient will receive
VAPS adds flow until the minimum Vt is met and is used if patient is unable to meet the
minimum Vt.
VII Critical Care Monitoring, ETCO2, Hemodynamic monitoring and Capnography:
Danny’s Lecture
ETCO2:
o Provides quantitative information on effectiveness of CPR compressions
o ETCO2 should increase with sufficient CRP
Critical Care Monitoring: No color change:
o
o
o
o
o
o
o
o
o
o
Look at HR, Sat., skin color
Auscultate stomach
CXR for expansion
Inadequate perfusion rhythm: assess ETCO2 for defects
Cardiopulmonary arrest: Lethal arrhythmias will stop perfusion
Maintaining Alkalodic pH to prevent vasoconstriction with patients that have increased
ICP (neuro. Pts)
Statusasthmaticus: increase peak pressure
VIDD: Ventilator Induced Diaphragm Deficiency
o Keep pt. triggering above the set rate at all times to avoid VIDD
Triggering represents 30-40% of the WOB
Hemodynamic compromised patient (we don’t want to trigger the vent)
Establishing Peep Levels:
o Optimal PEEP: is the PEEP that is a given that has the least amount of hemodynamic
effects on the patient.
o Is determined by trending the adjustments made
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Waveform Capnography:
o Assessment of: Perfusion and CO
Time constants (Kt):
o Is the rate at which alveoli fill and empty
o Emphysema Pts have a high Kt and require a longer expiratory time to empty
o Exhalation levels
o Zone I: is the start of expiration and is the content of CO2 relative to flow
o Zone II: is mid-expiration and is mixed alveolar gas with CO2
o Zone 3: is the end of expiration and contains rich CO2
If Auto-PEEP occurs in the rich CO2 Zone III:
o Hypercapnia
o Decrease ability to trigger
o WOB is increased
Auto-PEEP prevention and management:
o
o
o
o
o
Check the HME
Suction
Decrease TI to increase TE
Sedation is recommended for acute scenarios
Increase set PEEP to match the auto-PEEP (don’t exceed 75-80%)
Evaluating Asynchrony:
o Pt/Vent. Relationship
o Pt triggering can be achieved if less amount of pressure is needed to trigger
o Flow trigger: flow 2 L/min is sensed via the circuit. The vent then senses the flow and
initiated a breath to the patient
o Pressure time product: the higher the PTP the harder it is for the patient to trigger the vent
o Seen as air-starvation
PSV:
o PS is cycled off on the basis of flow
o Defaults on most vents at 25% of the total flow
o E-sensitivity
VPS: noisy pressure support
o PS set at 10 +/- 2
o Ideal for ARDS Pts
NAVA:
o Picks up diaphragmatic movement signal from the brain to the diaphragm and provides
support determined by the
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NM3 (NICO monitor):
o
o
o
o
o
o
Analyzes the Ve and PaCO2 to determine dead space ventilation
< 40% min. dead space calculation
<10 norm, minute Ve
> 40 Absence or pulmonary disease/airflow limited
A large waveform gradient on the Capnography wave indicated large PaCO2 to ETCO2
Mechanical VD
o Normal=15-25%
o On CMV=40-50%
Volumetric CO2:
o Limitations to ETCO2: only measures at that point in time
o VCO2 measures shows vol. of CO2 removal
o Occurs in three phases:
o ETCO2 32
o VT 600
o VCO2 50 ml/min
o ETCO2 and VCO2 have an inverse relationship with each other
o VCO2 gives faster results in regards to how the patient’s ventilation is:
VD/VT:
o Can be used as a predictor of mortality
o >5% = increase in mortality by 45%
o Decrease the VD/VT by Increasing PEEP
Sutter’s PM Study:
o Predicts the success of extubation
o Corrugated tubing connected to the patient port, connected to the device that measures:
o VC
o Flow
o Ve
o Pulse ox also attached
o Works like the Swan
o Set base line, adds VD to increase return and increase CO
o Not indicated for COPD pts.
VIII Hemodynamics continued: Mike’s Lecture
Physiology of BP:
o High BP strains the heart
3 factors control BP
o Heart
o Blood
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o Vessels
Factors causing cardiomyopathy:
o
o
o
o
Pericardium: covering
Pericardium: visceral layer
Myocardium: the musculature
Endocardium: what lines the chambers
The cardiac cycle:
o Preload: ventricular stretch imposed by volume
o HR
o CVP
o Ventricular compliance
o Aortic pressure
o Atrial contraction
o Thoracic venous pressure (PEEP)
o Afterload: the resistance to ejection of blood during systole
What affects BP?:
o Electrolyte imbalances
o Cardiac Tamponade
o Endocardium: caused by oral hygiene, drug abuse, diabetics using dirty needles. Causes
the valves to rot, leads to regurgitation and decreases the ejection fraction
o Normal EF= 60-70%
o <20% is bad
Hemodynamic calculations:
o
o
o
o
o
o
o
Normal CO= 5L or 4-6L (60ml/beat)
BP=CO x SVR
CO=SV x HR
SV is dependent on the preload and inotrophy of the heart
DO2= Hb x 1.34 x CO x SaO2/100
MAP= SBP- 2 x DBP/3
Ohm’s law of hemodynamics: MAP-CVP=CO x SVR or MAP≈CO x SVR
Oxygen delivery Diagram:
DO2
Hgb
SpO2
CO
BP
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SVR
Stroke volume
Preload
Inotropy
Heart Rate
Afterload
Everything below the DO2 effects the DO2
o Preload: (the volume of blood present in the ventricles), Inotropy (the force of contractility
by the heart related to the stretch of the myocardial cells) and afterload: the volume of blood
remaining in the ventricles after ejection), affect the stroke volume (the volume of blood
ejected from the heart with each beat) and the rate of contractility.
o SV and HR affect the CO: (the volume of blood pumped/min.)
o CO affects the Systemic vascular resistance and blood pressure
o Hgb, SpO2 and CO affect he delivery of oxygen
Hemodynamic disaster and treatments:
o Hypovolemic shock: loss of blood volume. Treat with IV fluids and positive inotropic
medications (epi).
o If it is hypovolemic shock then addition then this treatment should work
o A clinical assessment of hypovolemic shock is to lift the patients legs to assess if the SV
increases.
o If so underloaded volume exists then SV will go up
o If not then the patient is overloaded and SV will decrease
o Cardiogenic shock: Damage to the heart: treat with positive Inotropic medication or a
pace maker to regulate the rhythm
o Septic Shock (anaphylactic shock): Infection in the blood: give antibiotics to treat the
underlying condition
o Neurological Shock: Brain injury
Blood pressure and ventricular filling curve: Heart failure
o
o
o
o
Normal: 40
Mild heart failure: 45
Sever heart failure: <20
Ideally when increasing volume, we need to also increase the Force of contractility to
ensure the heart can unload the volume given. If not the volume will remain in the
ventricles causing increase work on the heart and a backup of blood in the heart
o Finding the optimal volume, includes finding the variations of inotrophy that work
o BP= SRV x HR X SV: SV x HR x CO
o Fluid loading
o Inotrophy or Preload (volume) must be given to increase BP (PEEP can also help
reduce preload to improve inotrophy
o Insufficient Inotrophy can cause overload and increase the afterload
o Afterload is also dependent on Vasodilation or Vasoconstriction
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o When if a patient in range of mild to severe failure, increasing inotrophy can their
position on the curve instead of fluids.
Types of Catheters:
Arterial catheter:
o Used to measure systemic Artery pressure, To collect an ABG inline,
o Insertion site: radial, brachial, femoral, pedal (umbilical cord for Neonates)
o Wave forms: up: is the increase of BP during systole, the dicrotic notch: is the closure of
the aortic valves, and the bottom is arterial end-diastolic pressure.
o Normal pressure= 120/80 mmHg: Systolic contraction = 100-140 mmHg: Diastolic 60-90
mmHg
o Increase Arterial pressure: for better circulatory volume and function, Sympathetic
stimulation, vasoconstriction and administration of vasopressors
o Decrease arterial pressure in the presence of: Hypovolemia (shock/vasodilation) and
Cardiac failure.
o Arterial Catheter/Pulse pressure: is the difference between atrial systolic and atrial
diastolic pressure
o Bradycardia: causes a lower diastolic pressure caused by low rates, that allows
blood volume more time for diastolic run off
o Tachycardia: causes a higher diastolic pressure caused by high rates, that allows
blood volume less time for diastolic run off
o Causes of decreased pulse pressure:
o Increased SV(Hypovolemia)
o Decreased blood vessel compliance (atherosclerosis)
o Bradycardia
Central Venous catheter:
o For assessment of right ventricular function and intravascular volume, for administration
of medications, nutrients or blood and an emergency route for temporary pacemaker
insertion
o Decreases in CVP: absolute Hypovolemia (blood loss) and Relative Hypovolemia
(Shock/vasodilation)
o Increased CVP: increased venous return (volume overload) and increased thoracic
pressure (PPV/Pneumothorax)
o Complications: Infection
o Bleeding
o Pneumothorax
Pulmonary Artery catheter (Swan Ganz):
o
o
o
o
o
For assessment of cardiopulmonary issues
Typically 110cm Length
Is a flow directed balloon catheter
Measures pulmonary artery pressure
Aspirate mixed venous samples
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o Inject medication
o Continuous monitoring of SvO2
o Balloon: 1.5 cc is the maximum inflation vol.
Indications:
o Hemodynamically unstable Pts, complex acute heart disease and acute severe pulmonary
disease
Measures:
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o
o
o
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CVP
PAP
PCWP
Mixed venous blood
Venous Saturation
CO
Provides cardiac pacing
Insertion site:
o at the subclavian internal or jugular vein, superior vena cava or right atrial
o Normal Pressure: 0-6 mmHg
Pressures in the heart:
o Right ventricle: 20-30/0-5 mmHg
o Occurs when the tricuspids open and blood flow into the ventricles causing the
pressure wave to increase
Pulmonary artery: 20-30/6-15 mmHg
o Where mixed venous blood samples are drawn
o Where the balloon on the catheter wedges a the small branch of the pulmonary artery
o The forward flow of the artery is occluded and pressure measured: normal 4-12 mmHg
Normal PA-wave form should return after the balloon is deflated
Pulmonary Wedge pressure: at the branch of the pulmonary artery
o Normal 4-12 mmHg (8 mmHg)
o PAP: can increase as a result of many issues in the lungs: hypoxia, pulmonary
vasoconstriction can cause blood to shunt
o Assesses left heart issues: (Pressure, Preload, end-diastolic pressure, ventricular filling
pressure)
Changes in the PAWP is:
o Decreased: Right heart failure, Cor Pulmonale, pulm-embolism, pulm-hypertension, air
embolism, Hypovolemia
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o Increased: Left heart failure, mitral stenosis, CHF/pulm-edema, High PEEP,
Hypervolemia
PA-catheter complications:
o Infection, bleeding, pneumothorax, pulm-artery hemorrhaging, pulmonary infarction, air
embolism, cardiac arrhythmias
What increased the PAP:
o
o
o
o
pulm-blood flow is decreased
increased pulm-vascular resistance
pulmonary embolus
compression caused by disease that restrict the pulmonary vasculature
What decreased the PAP
o decreased volume of blood ejected by the right ventricle
o Dilation of pulm-vasculature
Clinical assessment:
o Lung disorders:
o CVP Increased
o PAP Increased
o PCWP normal/decreased
o CO normal/with large PE
o Right Heart Failure:
o CVP Increased
o PAP normal/decreased
o PCWP normal/decreased
o CO normal/decreased
o Left Heart Failure
o CVP normal/increased in late stage
o PAP increased
o PCWP increased
o CO decreased
o Hypovolemia: everything is decreased
o CVP
o PAP
o PCWP
o CO
Other value to know:
o
o
o
o
o
Pulse Pressure: 40 mmHg
SV: 60-130 ml/beat
EF: 65-75%
SVR: <20 mmHg/L/min
PVR: <2.5 mmHg/L/min
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Pressure Dampening:
o The waveform doesn’t show a sharp wave form (no dicrotic notch)
o The catheter may be obstructed or kinked
ICU monitoring and equipment:
o
o
o
o
o
o
Chest tubes: fluid and air evacuation
Foley Catheter: urine drainage
Eye Tape: to maintain moisture in pts. eyes
GI Tube: to induce liquids, food or meds.
ICP monitor: determines pressures in the brain
Shunt: surgically placed tube in the ventricle that drains fluids into either (abdominal cavity,
heart or large veins of the neck
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