Question Answer
What is Barotrauma? Excessive pressure damage
What is Volutrauma? Excessive volume damage
What is Atelectotrauma? Damage from constant opening & closing of alveoli
What is Sheertrauma? Damage from alveoli smacking/bumping into each other; over-distended alveoli bumping into healthy alveoli
What is Surfactant Alteration? Surfactant washing to the bottom of the alveoli instead of surrounding it
What is Biotrauma? Over vented pts prod chemicals that cause organs to fail (MODS – multi organ disorder)
What is VIDD? Vent. Induced Diaphragmatic Disfunction – muscle atrophy
What is Vent. Assoc. Lung Injury? Damage to area above alveoli caused by vent.
What is Vent. Induced Lung Injury? Damage to alveoli caused by vent (ex: alveolar sheer)
PPV can lead to: Increased WOB (Intrinsic & Extrinsic WOB)
What is Extrinsic WOB? A result of ET tube too small, vent. settings, vent. tubing
What is Intrinsic WOB? A result of trying to overcome the normal elastic & restrictive forces in the lung
Steps to reduce WOB in mech. vented pts: Use largest adequate ET tube possible; suction, Peep/PSV; correctly adjust sensitivity; adequate flow rates; decr. airway resistance w/ bronchodilators, diuretics, etc.
PPV can cause? Increase in deadspace due to over-expanded alveoli constricting blood flow
Decrease deadspace by: Increasing Vt, larger et tube, trachea
Results of hypoventilation: Acidosis, coma, hyperkalemia, increase in ICP, vasodilation
How long does renal compensation take to off-set HCO3? 18-36 hrs
Results of hyperventilation: Alkalosis, hypokalemia, tetany, decrease in cerebral perfusion, difficult weaning, vasoconstriction, lowers ICP, too long = Metabolic Acidosis due to HCO3 elevated.
Results of PPV on Pulmonary Blood Flow: Decreased CO, redistribute to lung periphery instead of central area, V/Q mismatch & physiologic deadspace, decrease shunting w/ PEEP
Results of PPV on Cardiovascular: Increase thoracic vessel pressures; Decrease venous return to thorax, pre-load, SV, CO, & systemic BP.
Results of PPV on Renal System: Decrease CO = decrease in urine formation & output; redistribution of blood flow w/in kidneys causes less urine, creatinine, & sodium excreted
Results of PPV on ICP: Increased central venous pressure = decr. venous return = incr. blood vol. in cranium = incr. ICP = decr. cerebral perfusion pressure = cerebral hypoxemia potential.
Clinical risks of PPV on ICP: Pts who already have incr. ICP, closed head injuries, cerebral tumors, post neurosurgery
Mean Airway Pressures (MAP): The average airway pressure throughout the vent cycle (I:E); affected by rate, I time, flow, pressure, or PEEP; MAP > 12 @ risk for barotrauma
Normal MAP: 0; less hemodynamic compromise if kept @ a minimum
Paw can be kept lower by: Changes in inspiratory gas flow & pattern, I:E ratio, PEEP, SIMV
Effect of ABG values on renal function: PaCO2 > 65mmHg = decr. renal function; PaO2 decr. due to vasoconstriction = decr. renal function; PaO2 < 40mmHg = dramatic decr. of renal function
What is Auto Peep? Inhaling too much & exhaling too little / air trapping.
Complications of Auto Peep: Barotrauma, tension pneumothorax, circulatory depression, incr. WOB, decr. CO & venous return
Results of Vent. Assoc. Lung Injury (VALI): Vent. Assoc. Pneumonias (VAPS); oxygen toxicity (ARDS); barotrauma (pneumothorax, pneumomediastinum, subcutaneous emphysema); over-distention of the lungs
Results of Vent. Induced Lung Injury (VILI): Altered lung fluid balance; incr. endothelial & epithelial permeability; severe tissue damage; collapse of the alveolar units.
Hazards of O2 therapy w/ Mech. Vent.: FiO2>60% more than 48hrs = N washout; FiO2 @ 100% can cause damage in 6 hrs; decr. compliance, surfactant prod., tracheal mucus flow; capillary injury; progressive formation of absorption atelectatis; possibly ARDS
What is alveoli instability? Opening & closing of alveoli (atelectotrauma) causing milking out of surfactant & alveolar instability
Causes of ARDS: A-airway pressures(peak & plat); R-refractory hypoxemia; D-diffuse infiltrates; S-some good lung
4 types of barotrauma assoc w/ MV: Subcutaneous Emphysema; Pneumodediastinum; Pneumothorax; Pneumopericardium
Body positioning w/ Unilateral Lung Disease: Independant lung ventilation (2 vents); pt’s good lung is down.
Body positioning w/ ARDS: Prone (face down) – pt can develop swelling in face/head/eyes if not routinely turned.
Most important factor when evaluation pt for weaning: Was there a significant improvement or reversal of what caused the pt to be put on mechanical ventilation initially.
Weaning Parameters: Acid-base balance, anemia, cardiac arrhythmias, caloric depletion/nutritional status, fluid balance, hemodynamic stability, infection, physiological condition, renal function, state of consciousness, pain, sleep deprivation
VC (to wean): > 10 to 15 ml/kg
Ve (to wean): < 10 to 15 L/m
Vt (to wean): > 3-5 ml/lb or >300mL & <700mL
RR (to wean): < 25 breaths/min
MIP/NIP (to wean): -20 to -30cmH20
RSBI (to wean): < 100
Dynamic Compliance (to wean): > 25 mL/cmH20
Vd/Vt (to wean): < 60%
% Shunt Qs/Qt (to wean): < 20% to 30%
Physical signs of increased WOB: Use of accessory muscles; asynchronous breathing; sweating; anxiety; tachypnea; pt asynchronous w/ vent; substernal & intercostal reactions
3 Common Weaning Methods: T-Piece/Trach Collar Trials; SIMV; CPAP/PSV/Tube Compensation
Weaning w/ T-Piece/Trach Collar Trials: FiO2 5-10% higher than vent setting; monitor pts appearance, cardiac & ventilatory statuses, check ABG’s, common in PACUs, always have pulse ox on pt for alarm purposes, for pts w/ only O in SAVO
Disadvantages to T-Piece/Trach Collar Trials: High level of staff attn; no backup ventilation; no alarms; incr. WOB
Weaning w/ SIMV: Assess pt; decr. rate by 2BPM; monitor vitals; check ABG’s 20-30mins post vent chg; cont. to decr. SIMV rate as tolerated by pt; *Considered very old school
Advantages of SIMV weaning: Provides backup ventilation; provides a method of giving large, periodic breaths; useful in cases of ventilatory muscle weakness
Disadvantages of SIMV weaning: Incr WOB due to sudden incr in madatory rate; time & labor intensive; lots of ABGs; more side effects from ventilation (muscle atrophy)
Weaning w/ SIMV w/PS: Helps overcome system imposed WOB; pt controls frequency, depth, & time of spont. brths; improves vent. muscle endurance; PSV levels can be set to optimize a reasonable Vt for a pt
Weaning w/ PSV/CPAP: PSV levels set between 5-10cmH20; set spont. Vt’s @ 300-600mL; set rate @ 15-20bpm; decr. psv levels by increments of 5 as tolerated
Weaning w/ Spontaneous Breathing Trials: Pt placed on spont. mode or CPAP w/ 0-5 PEEP; PS added @ a min. 5-7cmH20 to overcome WOB; hemodynamics & vitals monitored; ABG’s; *Most common weaning method
Tube Compensation: Mimics post-extubation; weaning tool used prior to extubation; overcomes WOB due to artificial airway; assists pt w/ spont. breaths; Assist Mode = tube comp. ON; Control Mode = tube comp. OFF
Weaning w/ BiPAP: For pts w/ no need for invasive airway; used to avoid re-intubation
Evaluation for Discontinuance of Mech. Vent.: Need for airway protection; ability to mobilize secretions; ability to effectively cough; good gag reflex; ability to ventilate/oxygenate w/o airway assistance; hemodynamic/vital stability
Common causes for weaning failure: Attempted wean too soon; Incr secretions = incr WOB; physiological dependence on vent; generalized weakness & fatigue; malnutrition
Equipment for Extubation: Ambu bag, O2 source & mask/cannula, suction equip, supplies for re-intubation if necessary, Race-Epi
Procedure for Extubation: *Notify Nurse* Monitor pts appearance & vitals, Semi or High Fowler’s position, Pre-Ox @ 100%, suction, loosen tape & deflate cuff, pt breathe in deep & cough – pull out tube @ cough, return FiO2 to pre-extubation rate, encourage pt to deep brthe & cough
Most COMMON Extubation Complication: Sore throat & hoarsenss
Most SIGNIFICANT Extubation Complication: Glottic Edema or Subglottic Edema
Glottic Edema: Usually involves the vocal chords & can be tx w/ cool mist, race epi, and/or heliox
Subglottic Edema: May cause complete obstruction requiring immediate re-intubation or emergency trach
Mild Stridor tx w/: Cool Mist (CAM)
Moderate Stridor tx w/: Race-Epi
Marked Stridor tx w/: Re-intubate
Long-Term Ventilation: Pts who are no longer acutely ill but who are presumed to have a permanent need for vent support
Question Answer
What are the circuit basics for the PB 840? Double circuit (heated or non heated wire) Filters: Insp/Expiratory (smaller w/mount clip for NICU; regular for adults
How do you clean the PB 840? Change Circuits and filters, wipe down with approved cleaner
Functionality Turn, Touch Access
The air compressor is separate and may provide up to 200 L/minute flow w/minute ventilation of 50 L/minute
GUI stand for Graphical User Interface
The GUI contains the screen and is “AKA” the brain; input data
The BDU stands for Breath Delivery Unit
The BDU is the box and is also known as the lungs or heart; performs the task
The BDU has a flow transducer, fully charged battery and internal air compressor
The monitor sends information to the lower portion of the vent and receives information to monitor graphics.
The rectangular box contains the batter and has a 45 minute life if fully charged
Portions of the screen top includes patient data and graphics bottom includes ordered parameter and alarms
Self Testing includes the POST EST SST
The POST is the Power on Self test and occurs automatically.
The EST is the Extended self test and is done every 6 months by biomed
The SST is the short self test and takes 3 to 6 minutes. It is a function test and must pass to use. You must have an open circuit when the machine is turned one
The SST works by hitting SEST on the screen and then there is five seconds to hit the EST
The MA1 has the following modes Control-VC AC-Volume Controlled IMV
The 84o has the following modes AC-VC or PC SIMV- VC w or without P/S; SIMV PC w or without P/S Spont-with or without PS
Assist control is volume or pressure targets
In assist control breaths have one of the following preset volume preset pressure volume targeted
Pressure is a square wave form
Flow is decelerating
In AC/VC TLC is as follows T-RCT/P or F triggered L- Flow C-It
The settings in AC/VC are rate volume peak insp flow fio2 Trigger PEEP Alarms
The advantages of AC/VC are guaranteed set VT gauaranteed VE
The disadvantages of AC VC are pressure varies which can lead to potential barotrauma
In AC/PC the TLC is T-RCT/ P or F L-Pressure C-It
The settings for AC/PC are Rate PIP IT O2 Trigger PEEP Alarms
The advantages of AC/PC are control pressures
The disadvantages of AC/PC is that TV and VE can vary and there is a variable Peak flow
SIMV is the same as IMV except it avoids breath stacking
If a pts spontaneous breath is initiated at the same time as a mandatory breath is required it will deliver an assisted mechanical breath (like and ac breath)
What are the indications, advantages and complications of SIMV same as with IMV, except machine breaths are synchronized with pts spontaneous breaths
CPAP is used on spontaneous breaths when there is no pressure support
Spontaneous made includes NO set rate and may be used with CPAP and/or Pressure Support
What else must be set in spontaneous mode? Apnea parameters
What are the indications for spontaneous mode? Facilitate weaning
What are the complications of spontaneous mode? muscle fatigue Increased WOZBZ
Mean airway pressure is the average pressure in the airway during one complete respiratory cycle
Mean airway pressure is affected by pressure and time and the relationship is directly proportional.
The greater the mean airway pressure the greater the risk of barotrauma.
MAP does have some oxygenation benefits especially when used with the inverse ratio ventilation
MAP should be less than CVP
Normal MAP is 5-10 cmH20
Map for obstructive patients is 10-20 cmH20
MAP for ARDS patients is 15-30 cmH20
MAP on the 840 Ventilator is calculated based on 1 RCT
Intrinsic PEEP is unintentional PEEP and may also be termed as Auto-PEEP Inadvertant PEEP Occult PEEP
Unintentional PEEP during mechanical ventilation is present when end-expiratory pressure does not return to baseline pressure
Unintention PEEP is commonly associated with significant airway obstruction insufficent flow rates rapid respiratory rates
What are the complications of inadvertant PEEP? barotrauma and decreased CO Increased WOB
How do you correct Auto-PEEP? increased expiratory time (with flow or rate change) Reverse the airway obstruction
PEEP can reduce effects of Auto PEEP
List of ways to fix Auto-PEEP increase Peak Flow Decrease Respiratory Rate PEEP Bronchodilators
What is the formula to calculate MAP? (It*PIP)+(ET*PEEP)/RCT
When using a ventilator in which peak flow is preset a change in flow wave form from square to any other pattern will change I time
Any flow wave form other than square must be calculated as such It=RCT/Total Parts of the I:E ratio The I:E will come from the vent
Raw cannot be calculated when the flow is not constant
Pressure support (PSV) provides a preset pressure plateau to the patients airway for the duration of a spontaneous breath.
PSV can be used with SIMV or as a stand alone mode
PSV will augment a patients spontaneolus VT
PSV will be terminated when the patients flow drops to to a predetermined level
What are the indications for PSV? It facilitates Weaning Helps overcome airway resistance
You use an expiratory hold maneuver to find the AUTO PEEP
Pressure support must be automatically set at what without pressure support to overcome Raw? 1.5 cmH20 over the PEEP level
In PSV what is the trigger, Limit, Cycle? Trigger-Pressure/Flow Limit-Pressure Cycle-E-Sensitivity
PSV is cycled when a patients inspiratory flow drops to a predetermined level.
E-sensitivity is the sensitivity required to cycle spontaneous pressure supported breath into exhalation.
Expiratory Sensitivity (Esens) is defined as the percentage of the projected peak flow at which the ventilator terminates flow, and thus cycles from inspiration to expiration during spontaneous breathing.
Some ventilators have already predetermined E-sensitivity
ESensitivity can be adjusted up if there is a leak in the cuff
the smaller the e-sensitivity the longer the I time
Th larger the e-sensitivity the shorter the I time
What is the predetermined E-sensitivity on several vents? Servo 900C 25% Servo I- 40% Galileo-25%
The default E-sensitivity on the PB 840 is 50%
Inspiratory rise time % is also known as Pramp
Inspiratory rise time or Pramp determines how quickly the pressure will rise to its peak
Pramp is only active in a pressure mode of ventilation
The more increased Pramp the sharper the pressure
Inspiratory rise time can blunt flow so that the pressure doesn’t rise immediately.
Pramp changes pressure curve by manipulating flow
Rise Time is 1-100 in range
If rise time is set too low or too high tidal volume may be reduced or increased
What are the alarm parameters for fio2? +- 7%
What are the alarm parameters for VE? 2-4 liters above observed VE
What are the low exhaled VE alarm parameters? 1-2 liters below observed VE
What are the parameters for high respiratory rate? 10-15 breaths/minute over observed rate 30 breaths/minute is good
Dsens alarm parameters disconnect sensitivity 20-95%
PEEP(TOT)/PEEPI is equivalent to Expiratory Hold Maneuver
PO.1 can be found in respiratory mechanics and measures pressure generated during the first 100 milliseconds of inspiration against an occluded airway
The apnea alarm is usually how long for an adult? 20 seconds
When setting apnea parameters it is import to consider the fluctuations in patient’s spontaneous rate
Some ventilators require the apnea parameters to be programed but others have the apnea parameters predetermined.
The other puritan bennette 840 features include pressure ventilation volume support neomod bilevel PAV+ Respiratory mechanics tube compensation
PAV+ stands for proportional assist ventilation
Proportional assist ventilation is when the patient generates flow and volume and the machine will push pressure based on their needs to assist.
For proportional assist ventilation a percentage is chosen and is what percentage the machine will add to help ventilation (5-100%)
What are the advantages of volume ventilation? Tidal volume is guaranteed
What are the disadvantages to volume ventilation? pressure is not limited which may result in unnecessary barotrauma. Flow rate is fixed (limited, therefore patient cannot control flow demand
What are the advantages of pressure ventilation? Pressure is limited so barrotrauma risk is decreased. Flow rate is variable and changes in response to pt effort/lung characteristics. More even distribution of gas flow to lung, resulting in lower pressure requirements to achieve VT.
what are the disadvantages to pressure ventilation? VT varies with changes in resistance and compliance. May be uncomfortable if the inspiratory time is not set appropriately.
Volume support is pressure support ventilation with target volume.
What is the TLC for volume support? T- Patient (flow or pressure) L-Pressure Limited C-Patient (Flow-ETS)
For VS pressure is adjusted to meet the target volume but will not exceed high pressure limit minus 5 cmh20
If apnea the following with associated parameters must be chosen VC or PC
Bilevel ventilation provides 2 levels of PEEP or C PAP
Rate and Time for what must be set? PEEPH and PEEPL
How is time shown for bilevel? TH and TL
Pressure support is set for Spontaneous breaths
What are the advantages to BiLevel Ventilation? Increased Patient Comfort Reduced Requirement for sedation Prevention of alveolar collapse and overdistention
The PEEP High can be set between 5 and 90 cmh20
The PEEP low can be set between 0-45 cmh20
PEEP high can be set at 2-3 cmh20 above Mean airway pressure
PEEP high can also be set at 12 above Ppl
Bilevel ventilation can cause airtrapping