Ventilation Strategies
Ventilator parameters:
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PIP: Pressure is set in PC and also PRVC, it is variable in VC and also PRVC. PIP is typically the
total pressure on inspiration and is a combination of the set pressure limit on PC and peep
combined. When assessing note changes in PIP by looking at previous ventilator checks.
Increases in PIP may represent changing compliance (static/elastic resistance, dynamic/frictional
resistance from increased RAW), decreases in PIP represent a leak or improving compliance.
o Assess patients airway (biting, secretions, kinked tubing), breath sounds (secretions,
bronchospasm, absent/diminished from atelectasis…), graphics (pressure-volume loop
for over distension, leaks
o PIP should be kept lower than 40 cmH2O if possible (the lower the better). Higher
pressures= over distention, decreased venous return, decreased perfusion to the
kidney/GI tract, increased intracranial pressure
o Increases to flow, volume, rate and peep will increase PIP
o Keep high and low PIP alarm 10-15 above/below patients PIP and readjust alarms as
needed
o Increased PIP will be represented by a beak like appearance on the pressure-volume
loop
o Increased PIP = increased RAW = decreased dynamic compliance
o Change patient to lung protective strategies (low VT, high rates, peep) if high PIP is
associated with decreases in static compliance
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Plateau pressure (static pressure): note changes in Plat by looking at previous ventilator
checks. Increases in Plat may represent changing compliance (increased Plat = decreased static
compliance. Decreasing Plat = improving compliance
o Obtained by doing a inspiratory pause of 0.5-1 second, Plat will always be lower than PIP
o Represents elastic properties of the lung tissue, the breath hold allows for an
assessment of the distendibility of the lung at zero flow
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MAP (Paw): Increase in MAP associated with increase in PIP, PEEP/auto-PEEP, and decreasing
compliance. Decreased MAP associated with improving compliance, leaks
o Everything effects MAP, including I-time, flow, VT, rate, PIP
o Higher MAPS used for lung recruitment
VT: assess set/inhaled VTi and exhaled VTe, differences greater than 50 ml represent a leak. Set
in VC and PRVC (targeted), and variable in PC mode depending on lung compliance
o Set 5-7 or 8-12 ml/kg, adjust VT first to correct respiratory acidosis unless PIP is high or
patient is at high end of VT range.
o Spontaneous VT is 5-7 ml/kg, this is the goal VT for patients spontaneous breaths on the
ventilator. Increase PSV to increase spontaneous VT to achieve 5-7 ml/kg
o low VT alarm associated with leak or high pressure alarm
o Increasing PEEP in a non-compliant lung will increase VT and lower PIP by improving
compliance
o Increased VT represents auto-peep/breath stacking increased compliance, inline
nebulizer.
o Assess chest rise/presence of chest tubes, pressure-volume loops, and volume-time
graph. If patient is on SIMV mode, assess spontaneous vs. mechanical VT
o Keep VT alarm 200 below observed VT, and 200-300 above observed VT
Total Rate: total of set and triggered or spontaneous rate. On AC mode all breaths are
considered controlled, so the rate is set and triggered. On SIMV the rate is set and also
spontaneous on spontaneous mode all breaths are spontaneous
o If a patient is not breathing over the backup rate, the total rate will equal the set rate
and is time triggered. Total cycle time (TCT) is determined by the set rate and represents
how many cycles of inspiration and expiration occur per minute
o Increases in rate may be associated with pain, anxiety, fever, tachycardia, increased
oxygen consumption, infection, metabolic acidosis compensation, asynchrony with vent,
medications, decreased VT/atelectasis, neurological impairment (biots/cheyne stokes)
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Decreases in rate may be associated with sedation, over ventilation (blowing off too
much CO2, knocking out respiratory drive), decreased drive from neurological
impairment/brain bleeds
Total PEEP: Set peep and auto-peep. Auto-peep assessed by performing a expiratory pause and
also by looking at the flow-time graphic.
o Correct auto-peep by increasing E-time by increasing flow if on VC, or decreasing I-time
if on PC or PRVC
o May also add PEEP (Add PEEP to make NEEP ZEEP), decrease rate or volume or sedate
the patient
o Auto-peep will lead to increases in MAP, PIP and may lead to patient ventilator
asynchrony, difficulty triggering the vent on, and possibly barotrauma/pneumothorax
o The use of PEEP used to increase FRC, compliance and oxygenation. Initiated when a
patient is on 60% FIO2 with refractory hypoxemia. May increase PEEP in increments of
1-2 cmH2O. PEEP may cause a decrease in venous return, as most blood returns to the
heart normally on exhalation. Use optimal PEEP (which is the amount of peep required
to improve compliance and oxygenation with the least effects on blood pressure/cardiac
output)
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I:E ratio: a product of inspiratory time and expiratory time and rate. Keep 1:2-1:4 for most
patients, With air trapping/auto-peep allow for longer E times.
o Increase E time by increasing flow or decreasing I-time
o Inverse I:E ratios used for lung recruitment in ARDS, but is RARE
o Be able to calculate I:E ratios
Flow: Set in volume control along with flow pattern (Square or decelerating)
o When changing from a square to a decelerating flow pattern, you may have to increase
the flow rate to maintain the same I:E ratio
o Flow set 40-60L, may set higher for COPD patients to allow longer E times
o Calculated on PC or PRVC by taking VE x (I+E)
o Inadequate flow rates will cause patient asynchrony, assess for this by looking at the
pressure-time graph
Minute Ventilation: Rate times volume, may be mechanical or spontaneous depending on
mode. Ve = RR x VT, Ve kept around 6-10L. Increases in Ve relate to increases in VT and/or rate.
Always measured in liters. May be set on certain ventilators instead of setting VT and Rate, such
as the Drager (Called MMV, mandatory minute ventilation), VT and RR would fluctuate to
maintain a constant Ve in this mode, rarely used.
Pressure Support: Set to assist a patient’s spontaneous breath in SIMV or CPAP modes. Set
above RAW and set to achieve a spontaneous VT of 5-7 ml/kg.
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Typically set 5-15 cmH2O
Sometimes referred to as a mode itself
Alternatives to PSV are Volume support where a target volume is set and psv fluctuates
to maintain this VT on spontaneous breaths. Automatic tube compensation is set to
deliver extra flow into the circuit and ETT to simulate an electronic extubation/t-tube
Vital signs/patient monitor:
 HR: increases (pain, anxiety, hypoxemia, fever, SVT, A-fib, A-flutter…), decreases (sedation, AV
blocks…)
 RR: increases (metabolic acidosis, decreases tidal volumes, fever, increase O2
consumption/infection/fever, pain/anxiety, asynchrony, brain issues)
 Blood Pressure: Increases (Hx of hypertension, medication, stroke, hypervolemia, stress, fluid
overload/renal failure), decreases (excessive PEEP/positive pressures, hypovolemia,
shock/sepsis, cardiac failure)
 Temperature: increases (infection, medication…) decrease (hypothermia…)
 SpO2: COPD with hypercapnia keep 88-92%, everyone else >92%
 ETCO2: Keep within normal range per patient’s condition, trend with ABG as baseline. 3545mmHg. If reading lower than PaCO2, assess for possible dead space/pulmonary
emboli/bronchospasm/leak in circuit (room air contamination)
 ICP: if patient has had a craniotomy, keep pressures as low as possible, keep stress at a
minimum, suction minimally. Keep value less than 20 cmH2O
EKG/Rhythm:
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Note rhythm/regularity/rate.
Do not aggravate/suction the patient with unstable rhythm (V-tach, multiple PVC’s…)
Hemodynamics:
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PAP
CVP
Vent Strategies
For all patients, keep the HOB at 30 degrees or more to decrease incidences of VAP, suction above the
cuff. Perform proper oral hygiene and suctioning. Check cuff pressures and re-tape as needed.
Normal Lung Compliance
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Initial setup, no known ABG or history of patient condition
o AC or SIMV mode
o Rate 8-12
o VT 8-12 ml/kg per IBW or PC 15-25 cmH2O, or PRVC
o FIO2 40-60%
o Flow of 40-60L or I-time 0.9-1.0
o PEEP 0-5
o Sensitivity 1-3 either flow or pressure
o Alarms: High Pressure 10-15 above observed PIP, VT 200-300 above/below observed VT,
Rate 10-15 above/ below observed rate, Ve 2-3L above/below observed. Apnea alarms
20 seconds
Known ABG
o Apply settings per ABG. If patient has an acidosis, increase rate above 12
o If patient has refractory hypoxemia, increase FIO2 give peep
COPD exacerbation with air trapping
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Initial mode AC or SIMV, sedation to ease anxiety and agitation
Low VT (5-7 ml/kg per IBW) or PC (15-25 cmH2o) for lung protection, high rates to maintain
adequate minute ventilation (rates 16-20)
FIO2 per need, but keep relatively low per hypoxic drive
High flow rates 60-80L (decelerating flow pattern) or low I-times 0.7-0.8 to allow for increased
exhalation, PEEP 3-5 for auto-peep correction
Systemic steroids (Solumederol), bronchodilators
Adjust vent to maintain ABG per patients normal baseline PaCo2 and PaO2
Assess and suggest treatment for underlying cause of exacerbation
Pneumonia with congestion
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Initial mode AC or SIMV
Low VT or PC for lung protection, high rates to maintain adequate minute ventilation
Heated humidity/bronchial hygiene with CPT/percussion/IPV/ bronchoscopy/suctioning
Assess for developing ARDS, pleural effusions, sepsis
Assess WBC level and oxygen consumption, CXR
Antibiotics
ARDS/ALI
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Initial mode AC or SIMV, sedation to ease anxiety and agitation
Low VT (5-7 ml/kg per IBW) or PC (15-25 cmH2o) for lung protection, high rates to maintain
adequate minute ventilation (rates 16-20)
PEEP levels elevated to maintain FRC/compliance/oxygenation use optimal peep levels
High FIO2, titrate as low as tolerated
APRV for lung recruitment (set high PEEP, low PEEP, High time, Low time), used if conventional
is not maintaining lung recruitment, patient should be breathing spontaneously
HFV for lung protection (set AMP, MAP, IT%, FIO2, Hz) use if conventional ventilation is leading
to VILI
Arterial line placement for frequent ABG draws, monitor hemodynamics/blood pressures
Compliance assessments, CXR assessment,
Try prone positioning
Metabolic acidosis
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Assist in the compensation by hyperventilating
Status Asthmaticus
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Initial mode AC or SIMV, sedation/ possible paralytic to ease anxiety and agitation
Low VT (5-7 ml/kg per IBW) or PC (15-25 cmH2o) for lung protection, high rates to maintain
adequate minute ventilation (rates 16-20)
Systemic steroids (Solumederol), bronchodilators
Adjust vent to maintain ABG per patients normal baseline PaCo2 and PaO2
High flow rates 60-80L (decelerating flow pattern) or low I-times 0.7-0.8 to allow for increased
exhalation
Neuro/CVA
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Hyperventilation?
Medication induced coma
Keep ICP lower than 20 if possible, do not agitate, minimal suctioning and peep.
Post Op
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Normal settings, utilize peep for passive atelectasis protection
Pulmonary edema/fluid overload
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Utilize peep to improve FRC