Question Answer
What is respiratory failure inability of heart and lungs to provide adequate tissue oxygenation or removal of CO2
Hypoxemic respiratory failure PaO2 <60 on RA, regardless of CO2
Hypercarbic respiratory failure aka ventilatory failure or pump failure, PaCO2 >50
disease states that can result in respiratory failure acute respiratory failure; post op complications, sepsis, heart failure, pneumonia, trauma, ARDS, aspiration, COPD exacerbation, coma, neuromuscular
clinical symptoms of respiratory failure restless, tachycardia, head ache, hypotension, poor chest expansion, confusion, cyanosis, depressed respiration
what are the most common causes of vent support >WOB and muscle fatigue
what are the critical values for initiating ventilatory support in a pt with decreased ventilation PaCO2 >50 w/PH <7.2
what are the critical values for initiating ventilatory support in a pt with hypoxemia PaO2 <50-60 on 40-50%, A-a (on 100%) >350, PaO2/FIO2 <200
What are the critical values for initiating ventilatory support in a pt with inadequate lung expansion VT <500 mL/kg (norm 5-8), VC <10mL/kg (norm 65-75), RR >35 (norm 12-20)
what are the critical values for initiating vent support in a pt w/decreased muscle strength (tired) MIP >-20cmH20 (norm -80-100), VC <10mL/kg (norm 65-75), MVV <2xVE (norm 120-180L/min)
what are the critical values for initiating vent support in a pt w/>WOB VE >10 (norm 5-6), VD/VT >.6 (norm .25-.40)
what is impending ventilatory failure severe air hunger, resp rate >35, diaphorisis, use of accessory muscles, w/normal or near normal ABG (or prior to ABG if condition is progressing)
critical values or indications of impending ventilatory failure severe air hunger-RR>35, diaphorisis, use of accessory muscles, for neuromuscular-VC <1L or MIP <-20 to-30
what is refractory hypoxemia >PaO2 of less than 10 after increasing FIO2 by 20%, inadequate arterial oxygenation w/acceptable FIO2, PaO2 <60 (SaO2 <90) w/FIO2 >40-50%, P/F <300 ALI, P/F <200 ARDS.
Clinical values for ALI P/F <300 w/bilateral infiltrates
clinical values for ARDS P/F <200 w/bilateral infiltrates and Pul Cap Wedge press <18
What is CPAP spontaneous breathing with an elevated baseline pressure, small alveolar press to spont breathing pts on I and E to increase alv press, causes alveolar recruiting, benefit is lower FIO2 to maintain PaO2
what are the indications for CPAP refractory hypoxemia (PaO2 <60 on FIO2 >40-50%) with adequate ventilitory status (PaCO2 <45, PH 7.35-7.35) and to reduce the WOB in severe CHF.
What are the most common reasons for initiating vent support BIG 4-APNEA, ACUTE VENT FAILURE (>CO2 W/PH <7.2), IMPENDING VENT FAILURE (RR >35 AND “CLINICAL PRESENTATION), SEVERE O2 PROBLEM (SHUNT, DIFFUSION DEFECT)
Goals of mechanical ventilation 1-support and manipulate gas exchange (alv vent CO2 & PH), 2-increase lung volume (end inspiratory-end expiratory inflation and FRC), 3-reduce or manipulate WOB, 4-minimize cardiovascular involvement
What are the objectives of mechanical ventilation reverse-hypoxemia, acute resp acidosis and ventilatory muscle fatigue, to relieve resp distress, prevent or reverse atelectasis, allow for sedation and neuromuscular blockade, < O2 consumption, maintain or improve CO, <ICP, stabilize chest
Common initial settings for VT are ACNN- ARDS (4)6-8, COPD 8-10, Normal 10-12, Neuro 12-15 (all are based on IBW, ideal body weight)
Common initial setting for RR are ACNN- ARDS 12-15, COPD 10-12, Normal 10-12, Neuro 8-10 (all are based on IBW)
Common initial ventilator setting for normal lung are VT 10-12 mL/kg (can go to 15 for big person), RR 10-12 (can go down to 6-10 if VT is increased for big person), Flow is based on Itime, Itime target 1 second, I:E 1:2 or 1:3, mode VC-SIMV, Peep 3-5, FIO2 40-50% (in doubt use 100%)
Common initial ventilator settings for ARDS VT 6-8, RR 12-15 (can go to 30), Flow set to Itime, ITime target is 1.2 seconds, mode VC-CMV, PEEP 5-8, FIO2 100%
Common initial ventilator settings for COPD and status asthmaticus before venting COPD pt always try bilevel or bipap, VT 8-10, RR 10-12, Flow set to IT, IT target .8 to maximize Etime, mode VC-SIMV, FIO2 60-100, peep 3-5
Common initial ventilator settings for Post Op pt same as norm
Common initial ventilator setting for Neuromuscular Diseases VT 12-15, RR 8-10, Flow/ITime target 1 second, Peep 3-5, FIO2 40-50%
Common initial ventilator setting for head injury same as normal, but may adjust after 24 hours for increased ICP, hyperventilation to target CO2 of 25-30 to reduce ICP (<CO2 will cause vasoconstriction and <blood volume, therefore, reducing ICP
Common initial ventilator setting for Unilateral disease to prevent ventilation from going only to healthy lung, use Karlan’s ETT and add the second machine, set one lung to ARDS and good lung to ½ normal settings except RR increase to 12-15 to compensate for smaller VT. Or use HFJV high freq jet vent.
Common initial ventilator setting for spinal cord injury set to normal lung
what is a bronchopleural fistula persistent air leak into the pleural space. Caused by trauma, surgery or invasive procedure like central line or from infections
Management of bronchopleural fistula on ventilated pt assess leak size by measuring inspired versus expired VT, BFV need chest tube, VC not working change to high frequency, also keep PEEP to minimum or 0, and small VT 4-8, may need surgical repair.
What is optimal flow 40-80 L/min, set to meet pt inspiratory demand (so spont breaths will have enough flow and pt will not have to work to hard)
Who benefits from higher flows pts with >RAW like COPD, shorter Itime provides longer Etime to prevent airtrapping
Who benefits from lower flows ARDS, longer IT helps recruiting
Constant flow waveform in VC square or rectangular
WHAT IS BEST WAVEFORM FOR ARDS DECENDING
what are the hazards of a short IT (high flow) higher peak pressures and poor gas distribution
what are the hazards of longer IT (slower flows) increased Paw that can lead to cardio effects, shortens Etime, long ITime can cause air trapping
How do we shorten the Itime on a ventilated pt increase the flow
What are the parameters that must be set on a mech vent mode, VT, RR, I:E ratio, Flow, VE, PEEP, Trigger/Sensitivity, FIO2, Alarms
Setting flow if IT is 1 second (works on all machines except Servo) F equals VTx60, so for VT of 700cc, if IT is 1 second then .700×60 is a flow of 42L/min
Inverse ratio ventilation IRV IT is longer than ET
complication of IRV MAWP increases significantly, >VD, <Venous return, <CO, >autoPEEP
when would an IRV be used ARDS (rare)
Alv VE VA eq (VT-VD)xRR
advantages of NPPV (noninvasive positive pressure ventilation) avoid intubation and assoc complications, preserves natural defenses, pt comfort, maint speech and swallow, less sedation, intermittent use
disadvantages of NPPV pt cooperation needed, limits acess to airway and suctioning, mask discomfort, air leak, transient hypoxemia from lost mask, bipap limit to 20-30, time-consuming
who are best pts for NPPV sleep apnea, acute COPD exacerbation, premature extubation, acute resp failure, CHF
contraindications of NPPV cant tolerate or poor mask fit, secretions, severe hypoxemia, severe acidosis, hypotension, upper aw obstruction, prone to aspirations, need airway protection
what is full ventilatory support mechanical support such that all energy necessary for effective alv vent is provided-key is to set VT and RR to ensure a minimum effective level of alv vent (vt10-12 rr 10-12)
Partial ventilatory support using vent settings that require pt to provide some of the support (simv rates <10)
what modes allow for effective spontaneous breathing SIMV, PSV, VS (volume support), APV (adaptive support)
3 ways to trigger a breath are time, flow and pressure
PC-CSV pressure control-cont spontaneous ventilation
critical values for specific physiological to initiate vent support RR>35, VT <300 ml, RSBI >105 (RR/VT), MIP >30cmH2O, VC <1L (15-20mL/kg)
ABG consistent to mech vent PaCO2 >45-50 w/corresponding decrease in Ph, hypoxemia w/supplemental O2, PaO2 <60 w/FIO2 >40-50%
initial vent setup decisions indication, noninvasive/invasive, press/volume, partial/full support, Mode-AC, SIMV w/ or w/o PS, PSV, PSV, PCV, dual control