respiratory failure 2019... · 2019-08-01 · • dual/high flow oxygen: optiflow/airvo –normal...

Respiratory Failure 2019Michael Chandler, MD

Respiratory Failure• Noninvasive Management of Hypoxic

Respiratory Failure

• Noninvasive Management of Hypercapnic

Respiratory Failure

• Invasive Management of Respiratory

Failure

Respiratory Failure• Hypoxic: Not enough oxygen

– Increase FiO2

• Fraction of inspired oxygen

– Increase PEEP

• Positive End-Expiratory Pressure

• Hypercapneic: Too much carbon dioxide

– Increase Respiratory Rate

– Increase Tidal Volume (Vt)

• Vt = Volume air displaced with normal inspiration

and expiration when no extra effort applied

Hypoxic Respiratory Failure• Adequacy

– O2 Sats > 90% (> 88% COPD) = Adequate

• Brain getting enough oxygen

– Can determine by ABG but don’t need to

• Normal 80-100, Abnormal <80, < 55 Failure

Hypoxic Respiratory Failure• Efficiency

– How much O2 needed to get adequate sats

– Determined by ABG


– How much O2 needed to get adequate sats


• paO2 (O2 on ABG) / fio2 (ex .21 if on room air)

• aka p:f ratio

– Normal >425

– Severe Hypoxemia / ARDS <300


– How much O2 needed to get Adequate sats


• paO2 (O2 on ABG) / fio2 (ex .21 if on room air)

• aka p:f ratio

– Normal >425

– Severe Hypoxemia / ARDS <300

• At the bedside, if you need 100% NRB to keep

sats >90%, you know the p:f ratio ain’t good

– If sats are 100%, you don’t know how efficiently (or

inefficiently) patient oxygenating till you get that ABG

Hypoxic Respiratory Failure• Hypoxic: Not enough oxygen

– Increase FiO2

• Fraction of inspired oxygen

– Increase PEEP

• Positive End-Expiratory Pressure

MEDICAL OXYGEN• Tanks behind hospital have liquid O2

– Enough to run all sources for > 48hr

– Boils at room temp and explodes at higher

MEDICAL OXYGEN• “Warmed” to 71F

– Humans 98.6F

• By law, pressurized to at

least 100 lpm

– Humans 40-60 lpm flow

• Pressure regulator slows

down to 15-20 lpm AND

functions as on/off valve

– Humans generate addition

lpm flow on their own

OXYGEN TANKS• Stored at room temp

• Pressure regulator slows down to 15

lpm AND functions as on/off valve

• Usually about 600ish liters in std tank

– If set to 15 lpm = 40hr

OXYGEN CONCENTRATOR• Complicated stuff happens (see below)

– RA goes in, poops out 90ish % O2

– Low flow (1-5 lpm) & High flow 10 lpm

OXYGEN CONCENTRATOR

Hypoxic Respiratory Failure• Room Air

– 21% O2

• Nasal Cannula

– Add 4% O2 for each liter/min (lpm)

• Ex. 2 lpm is about 29% O2

– Tops out in Mid-30% range

• Ie. 6 lpm does not equal 45%

Hypoxic Respiratory Failure• Venturi (aka “Venti”) Mask

– Up to 50%

• Yellow = 28%

• White = 31%

• Green = 35%

• Pink = 40%

• Orange = 50%

– It will say on the adaptor how many lpm to

turn wall mounted O2 to

Hypoxic Respiratory Failure• 100% Non-Rebreather (NRB)

– Somewhere between 60-80%

– Reservoir stores O2 while you breath out

– Not a high flow oxygen system

• Thus, O2 diluted by entrained room air

Hypoxic Respiratory Failure• Dual/High Flow Oxygen: Optiflow/Airvo

– Heats O2 to body temp (from 71F)

– Humidifies

– O2 30-100%

– Flow (Inspiratory Flow) 10-60 lpm


– Normal human inspiratory flow 40-60 lpm

• If Optiflow set 40-60 lpm, pt getting O2 on dial

• If <40 lpm, pt getting less than what on O2 dial

– Airvo doesn’t need medical air (makes own)

• Optiflow does

• Can use on some general floors

– every 10 lpm

• 0.7 cmH2O PEEP, mouth closed

• 0.3 cmH20 PEEP, mouth open

Hypoxic Respiratory Failure• Dual/High Flow Oxygen: Optiflow


– May impair swallow

• Increase risk aspiration

• Research ongoing into flow rate adjustments


– Superior to NIV in pure Hypoxic

Respiratory Failure

• ie in patients without hypercapnia

• Decrease mortality/ Increase vent free (NEJM 2015)

• Other studies corroborate superiority or at least non-

inferiority in medical and surgical populations

Hypoxic Respiratory Failure• Still hypoxic?

– Need PEEP

• Emergency: Bag Valve Mask (BVM aka

AMBU) with PEEP valve


– Need PEEP

• Longer-term: CPAP/BIPAP*

Noninvasive Ventilator (NIV)

Ventilator

*qhs CPAP (5-7) / BIPAP (10/5) reasonable for atelectasis

patient who can’t / won’t use incentive spirometer

OR you suspect has occult Obstructive Sleep Apnea


– Need PEEP

• Longer-term: CPAP/BIPAP

Noninvasive Ventilator (NIV)*

Ventilator

*ICU only

Avoid NIV if only issue pneumonia


– Need PEEP

• Longer-term: CPAP/BIPAP

Noninvasive Ventilator (NIV)

Ventilator


– Need PEEP

– Need NARCAN?

• ex unconscious, 2mg (1mg per nares)


Respiratory Failure


Respiratory Failure


Failure

Hypercapneic Respiratory Failure• pCO2 >45 AND acidosis

– CO2-retainers

• Can’t maintain normal C02 due

to work of breathing, CO2 rises

– Serum bicarb rise to compensate

– Thus, normal or near-normal pH

Hypercapneic Respiratory Failure• Treatment

– Increase Respiratory Rate or Tidal Volume

• Ambu bag

• BIPAP/NIV

• Ventilator



• Ambu bag

• BIPAP/NIV

– Leak < 100 lpm

» Ideally < 75 lpm

– Be careful with Rate

» Central apnea legit use

» Drowsy bad idea

• Ventilator



• Ambu bag

• BIPAP/NIV

– Normal Vte 5-8 lpm

» Vte (Minute Ventilation)

– Light Exercise 12 lpm

» Mild Hypercapnea

– “Red lining” >20 lpm

» Ex DKA

• Ventilator



• Ambu bag

• BIPAP/NIV

– BIPAP different from NIV

» Newer devices closing gap but

• Conventional BIPAP still more mask leak

• A LOT easier to diagnose dysynchrony w/ NIV

» NIV IPAP 10, EPAP 5 = BIPAP IPAP 15, EPAP 5

• Don’t blame me

• Ventilator



• Ambu bag

• BIPAP/NIV

• VentilatorINTUBATE


Respiratory Failure


Respiratory Failure


Failure

Predicted Body Weight• Do not use

– Actual body weight

– Dry body weight

• Do use Predicted body weight (PBW)

– Based on patient’s height, sex

– Google ARDSnet, click PBW

ARDSnet NEJM 2000

Predicted Body Weight

ARDSnet NEJM 2000

Predicted Body Weight

Tidal Volumes• OPINION

• For vented patient with no lung dz

– 7-8 ml/kg

• For vented patient with lung dz

– 6-8 ml/kg

• For ARDS patient

– <6ml/kg

ARDSnet NEJM 2000

Mechanical Ventilation• Modern ventilators

– Not iron lungs

– Positive pressure not negative pressure

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwi6pKe70vHcAhVJcq0KHV-mCHUQjRx6BAgBEAU&url=https://www.outfrontmedical.com/puritan-bennett-840-ventilator-teaching-unit/&psig=AOvVaw1Jua2ssBRuUv91hToIe9Hj&ust=1534511329846709

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwi6pKe70vHcAhVJcq0KHV-mCHUQjRx6BAgBEAU&url=https://www.outfrontmedical.com/puritan-bennett-840-ventilator-teaching-unit/&psig=AOvVaw1Jua2ssBRuUv91hToIe9Hj&ust=1534511329846709

Mechanical Ventilation: AC• Assist Control

– Assist Breaths

• Triggered when patient effort detected

– Control Breaths

• Delivered at a fixed rate by the ventilator


– Volume Control (VC, “A/C”)

– Pressure Control (PCV)


– Volume Control (VC)

• You select Volume

• Will result in variable Pressure


• You select Pressure

• Will result in variable Volume

Volume Control

• Set: FiO2 PEEP Rate Vt

Volume Control in a patient without respiratory effort…

VtVt Vt VtVt

Mechanical Ventilator Modes: AC

Volume Control


VtVt Vt Vt

Volume Control in a patient breathing but slower than the set rate…

Vt


Volume Control


VtVt Vt Vt

Volume Control in a patient breathing faster than the set rate…

All breaths over set rate will be at full Vt.

VtVt VtVt


SIMV Synchronized Intermittent Mandatory Ventilation

• Set: FiO2 PEEP Rate Vt PS• Pressure support increases pressure in the tube to set level when

respiratory effort sensed.

VtVt Vt Vt

SIMV in a patient without respiratory effort…

Mechanical Ventilator Modes: SIMV

• Set: FiO2 PEEP Rate Vt PS

VtVt Vt Vt

SIMV in a patient breathing over the vent…

Any breaths over set rate will be pressure supported.

PS PS PS

Mechanical Ventilator Modes: SIMV

Spontaneous Mode Pressure Support ventilation

• Set: FiO2 PEEP PS (note: no set rate)

Spontaneous mode in a patient without respiratory effort…

Back-up rate will trigger after 30 seconds (VC).

Mechanical Ventilator Modes: Spont

• Set: FiO2 PEEP PS

Spontaneous mode in a patient with spontaneous breaths...

PS PS PS PS PSPSPS

Mechanical Ventilator Modes: Spont

• Hypoxic:• Increase FiO2

• Increase PEEP

• Hypercapneic: • Increase Rate

• Increase Vt

Mechanical Ventilator Modes: Rundown

• Volume Control:• Rate: 15 bpm (Patient breathing at 15)

• Vt: 500ml

• FiO2: 100%

• PEEP: 5 cmH2O

• ABG: 7.36/35/50/25

• What would you adjust on the vent settings?

Mechanical Ventilator Modes: Questions


• Vt: 500ml

• FiO2: 50%

• PEEP: 5 cmH2O

• ABG: 7.14/72/89/25

• What would you adjust on the vent settings?



• Vt: 500ml

• FiO2: 50%

• PEEP: 5 cmH2O

• ABG: 7.59/20/89/25

• What would you adjust?


Mechanical Ventilation: AC• Assist Control (Beginner)

– Volume Control (VC, “A/C”)


Mechanical Ventilation: AC• Assist Control (Advanced)

– Volume Control Plus (VC+)

• PCV where you pick target

Volume (Vt) and Insp Time

(Ti) and computer chip

adjusts pressure for you

– Bilevel/APRV

Mechanical Ventilation: AC• Assist Control (Advanced)

– Volume Control Plus (VC+)

– Bilevel/APRV

• Airway Pressure Release Vent

• High PEEP/Low PEEP

• PCV that allows spontaneous

(PS) breaths over AC breaths

• Paralyzed Bilevel/APRV = PCV


Respiratory Failure


Respiratory Failure


Failure

Thanks!

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respiratory failure 2019... · 2019-08-01 · • dual/high flow oxygen: optiflow/airvo –normal...

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