Critical Vent Management: Oxygenation

RRTMedic

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Let's start with the scenario.

You have a female patient in her 40s on mechanical ventilation for airway protection. After an acute change in condition, a stat CXR found a massive left tension pneumothorax. It was treated rapidly with chest needle decompression and chest tube placement. A repeat chest xray shows a resolved pneumothorax with dense opacities in the left lung with an appropriately placed chest tube. The right lung is unremarkable.

Current vital signs: HR 132/min, SpO2 60%, RR 30/min, BP 130/60

Significant ABG value: PaO2 30

Current ventilator settings:
PRVC
TV 450 ml
RR 18/min
FIO2 100%
PEEP 8 cmH2O
Insp Time 0.9 secs
Set I:E 1:2.7
Rise Time: 15%
Trig 5 lpm

Ventilator: Maquet Servo I

This patient needs transport from a tertiary ICU to Level I Trauma Center due to severe hypoxemia.

1) What's the name of the pulmonary condition this patient is suffering?
2) How would you manage this patient if your transport vent had every capability other than HFOV?
 

VentMonkey

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1) What's the name of the pulmonary condition this patient is suffering?
Given that this was an iatrogenic pneumothorax, and most pneumos post ventilator management are caused by pneumonias, coupled with "dense opacities" I am going with pneumonia induced ARDS. As far as it's severity, a look at the PaO2/ FiO2 ratio would be great.
2) How would you manage this patient if your transport vent had every capability other than HFOV?
Excluding ASV, most a PCV mode with the Vt started at with by the tertiary ED.

Obviously we're aiming for an SPO2 (>/=)93% for me while closely monitoring airway pressures (any sudden sustained spikes in flight on the vent would have my trigger finger itching for another dart).


If I am able to phone a friend, it would be the intensivist at the Level 1 receiving, if not them, then my medical director for consult on vent management in flight.

I would utilize the higher PEEP strategies while starting at an FiO2 of 1.0 and titrate that to my target SPO2 as well. The PCO2 isn't terrible, but a full, and recent ABG prior to transport would be optimal as well.
All I got for now @RRTMedic...lay it on me.
 
OP
RRTMedic

RRTMedic

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1) Hmmm good thought on the pneumonia... but I should have given more info. No signs of a pneumonia (ie previous CXR, afebrile, etc). Just a completely "whited out" left lung.

Alright you increased the PEEP. Let's say you increased the PEEP to 12 cmH2O and you switched the patient to PCV with no changes in rate, insp time, I:E...

For the sake of the scenario, let's say your transport time is 4 hrs.

After 20 minutes, you draw an ABG off of an A-line and do a POC gas. pH is WNL, but your PaO2 is 38 cmH2O.

Try again on the diagnosis :)
 

VentMonkey

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Sorry completely read the PaO2 wrong. So definitely failure, honestly I am drawing a blank on the diagnosis so I'll let some others perhaps with more ICU/ general ventilator experience chime in on this one...hence the last name, "Monkey".
 
OP
RRTMedic

RRTMedic

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Something like this after the chest tube...
(I just google searched an image...obviously this isn't the actual patient's cxr that I encountered)
left sided.jpg
 
OP
RRTMedic

RRTMedic

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Sorry completely read the PaO2 wrong. So definitely failure, honestly I am drawing a blank on the diagnosis so I'll let some others perhaps with more ICU/ general ventilator experience chime in on this one...hence the last name, "Monkey".
But keep going! You're on the right track with vent settings... what more can you do...
 

Midazzled

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What sort of plateu pressure do we have? What's the capnograph look like, and EtCO2? IBW?

There's a good chance this patient is over my head, and I too was going to suggest pneumonia.

Edit: you switched to PCV; what settings? Any changes in the patient other than what you reported in the ABG?
 
OP
RRTMedic

RRTMedic

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What sort of plateu pressure do we have? What's the capnograph look like, and EtCO2? IBW?

There's a good chance this patient is over my head, and I too was going to suggest pneumonia.
Hmm if we are at a PEEP of 12 and we probably have a pressure control of probably 15, so our peaks are at 27 cmH2O and I can go ahead and tell you the compliance of the lung is low, so probably looking at a plateau of 25 cmH2O.

I'll give y'all a hint. The diagnosis has something to do with a rare complication of chest tube insertion.
 

VentMonkey

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I'll give y'all a hint. The diagnosis has something to do with a rare complication of chest tube insertion.
Pleural effusion.
Edit: you switched to PCV; what settings? Any changes in the patient other than what you reported in the ABG?
I feel if I paralyzed them and kept them in an A/C with PCV I would have more control over their frail lung(s).

The key here to me is watching the already high risk airway pressures, especially in flight. This patient is a recipe for a re-pneumo with in the air, and a perfect "Boyle's Law" scenario as well.

Settings-wise:
Vt-IBW (4-6 ml/ kg)
f- 12-14 (paralyzed I can control it as well as WOB)
FiO2- 1.0 (100%)***
PEEP- perhaps begin in the 8-10 range***

***these two are the keys to this patients survival in transit for me (proper oxygenation); the FiO2 may need to be kept at 100% which is fine for the 4 hour transfer, the PEEP may need to be upped and I would like parameters from a physician as to how high they want it maxed out (this is a sick patient who definitely needs an intensivist consult). Pmean should NOT go above 30, another reason heavy sedation (assuming stable V/S) and/ or paralysis may be warranted. The lower the airway pressures the better, IMO.
 
OP
RRTMedic

RRTMedic

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Pleural effusion.

I feel if I paralyzed them and kept them in an A/C with PCV I would have more control over their frail lung(s).

The key here to me is watching the already high risk airway pressures, especially in flight. This patient is a recipe for a re-pneumo with in the air, and a perfect "Boyle's Law" scenario as well.

Settings-wise:
Vt-IBW (4-6 ml/ kg)
f- 12-14 (paralyzed I can control it as well as WOB)
FiO2- 1.0 (100%)***
PEEP- perhaps begin in the 8-10 range***

***these two are the keys to this patients survival in transit for me (proper oxygenation); the FiO2 may need to be kept at 100% which is fine for the 4 hour transfer, the PEEP may need to be upped and I would like parameters from a physician as to how high they want it maxed out (this is a sick patient who definitely needs an intensivist consult). Pmean should NOT go above 30, another reason heavy sedation (assuming stable V/S) and/ or paralysis may be warranted. The lower the airway pressures the better, IMO.
So I definitely agree with paralyzingly. Paralyzingly will decrease metabolism due to the muscles not exerting any energy, allowing for less oxygen consumption.

In the above quotes I mentioned that at a PEEP of 12 and a Pressure Control of 15, you probably have a plateau of 25. That's gives you some wiggle room on PEEP.

And I'll go ahead and give you the diagnosis: Ipsilateral Reinflation Pulmonary Edema.
 
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OP
RRTMedic

RRTMedic

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Duh? Clearly any fool could see that??:D
Haha to be honest, I have only seen this once and had to ask a resident what in the world was going on. 1-14% chance it will happen. Put the patient on crazy vent settings though! Was wondering if you would max out to the point I did ;)
 

Midazzled

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I am highly interested in CC and plan on doing a UMBC or Creighton course, hopefully soon.
 

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