Test 5 Flashcards
Monitoring lung and chest wall compliance
- Compliance testing for inflection points
- Static compliance
Compliance testing for inflection points
- Deliver set volume and measure pressure, add a set volume and pressure until full
- Plot these points and look for lower inflection point and upper inflection point
- Ventilate with PEEP slightly above inflection point and / or plateau pressure below upper inflection point
Static compliance
^V/^P
Two kinds of compliance
Dynamic and Static
-static is the more common
Dynamic: Peak
Static: insp hold/ pause/ plateau
Corrected Vt
corrected tidal volume should be used because you want to use only the volume to the lung, not the circuit
Try to use the Vt and Plat from the same breaths
-AutoPEEP should be measured and used if possible
Corrected Vt/ Plat-PEEP=Clst
What does static compliance tell us
stiffness of the lungs and chest wall
Compliance values for intubated pt
Norm 70-100 unusual for vent pt mild 40-70 moderate 30-40 Severe <30 ARDS <25 unweanable
Whats most important when looking for changes in lung status
Trending values (plat)
Airway resistance equation
^Pressure/ ^flow (V) ((lpm-> L/S=cmH2O/L/s))
Peak pressure-Plateau pressure/ Peak Flow (L/s)
or just
Peak - Plateau
Ranges for Airway Resistance
norm 0-10cmH2O/L/s
moderate 11-15
severe >15
Airway pressure ranges
Peak: great concern over 50
Plateau: kept below 30-35 (below 30, O2 problems)
-consider PCV if pressure excessive
-Mean airway pressures increase for better oxygenation reduce to keep side effects down to a minimum
Mean Airway Pressures
increase for better oxygenation, reduce to keep side effects down
AutoPEEP
air that is not exhaled before next breath
Best way to tell if there is auto PEEP
check the flow/time curve
-if flow does not return to baseline, pt has autoPEEP
(this does not give you a number)
Do autoPEEP maneuver to get actual number (exp.hold)
How to fix Auto PEEP, increase expiratory time. how?
Shorten Ti(pt. with obstructive airways) -will go in faster, increasing pressures Decrease RR, lengthen resp cycle -Change CO2 and pH Decrease Vt, less to exhale Increase flow rate, -square waveform SIMV mode match PEEP
Inverse I:E when
ARDS, improve O2
Monitor breathing efforts and patterns, Work of breathing
small airway:us as large ETT as possible system imposed: effort to open valve to initiate breath(demand valves) Use flow sensitivity PSV sensitivity set appropriately keep flows set appropriately keep Raw low, bronchodilators, suction, etc treat cause of MV
Monitoring breathing efforts and patterns
WOB
Esophageal pressure monitoring:amount of pressure within chest
Oxygen cost of breathing: Paralyze pt, O2 is used on important organs
Assessing ventilatory drive, daily spontaneous breathing trial: decreasing pt problems, extubate ASAP