Can someone drop some knowledge on me?

[SomethingFishy]

I'm getting ready to start my MICU rotation here in about a month and I'm really confused on some things because I have absolutely no experience in ICU settings. Hoping someone can clear this up for me before I get in there..
1)What is the difference btwn CPAP and BiPAP? When would you use one versus the other?
2)Which medications are typically used when someone is on the vent for sedation and analgesia? Also, do you always need to use a paralytic such as rocuronium?
3)Are there any good websites or resources on commonly seen ICU problems?
Thanks

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[smq123]

I'm getting ready to start my MICU rotation here in about a month and I'm really confused on some things because I have absolutely no experience in ICU settings. Hoping someone can clear this up for me before I get in there..
1)What is the difference btwn CPAP and BiPAP? When would you use one versus the other?
2)Which medications are typically used when someone is on the vent for sedation and analgesia? Also, do you always need to use a paralytic such as rocuronium?
3)Are there any good websites or resources on commonly seen ICU problems?
Thanks

1) This thread contains some pretty useful info: http://forums.studentdoctor.net/showthread.php?t=498040

2) I've seen intubated patients on propofol and fentanyl drips.

 

[Dimoak]

2.) I could be wrong, but I think it has to do with, among other things, preventing muscle spasm that could dislodge the tube as well as other issues. Propofol and Etomidate are among the most commonly used sedatives, while opioids are used for analgesia. I'm not an expert, so please take this post with a grain of salt.

3.) http://www.learnicu.org/Pages/default.aspx may be a good resource.

 

[The right Path]

I'm getting ready to start my MICU rotation here in about a month and I'm really confused on some things because I have absolutely no experience in ICU settings. Hoping someone can clear this up for me before I get in there..
1)What is the difference btwn CPAP and BiPAP? When would you use one versus the other?
2)Which medications are typically used when someone is on the vent for sedation and analgesia? Also, do you always need to use a paralytic such as rocuronium?
3)Are there any good websites or resources on commonly seen ICU problems?
Thanks

1. CPAP and BiPAP are modes of noninvasive respiratory support. (CPAP is also a mode used when trying to wean from invasive mechanical ventilation). With both noninvasive modes, the patient wears a mask or nasal "pillows" (like nasal cannulas that seal against the nares). At any rate, the device needs to have a reasonably good seal against the skin to prevent air leak. The mask is attached to a hose that attaches to a machine. The FiO2 is programmed into the machine, although for a CPAP only machine, it is common to just use room air. Sometimes oxygen from the wall meter is connected to the machine to "bleed in" such as like 2L/min, but that is not a precise FiO2 (and that is with a CPAP machine only). The machine is programmed to provide a certain amount of pressure.

And here is where CPAP and BiPAP differ. With CPAP, the amount of pressure programmed is constant and the purpose is generally to overcome soft tissue airway obstruction such as with sleep apnea. There are CPAP machines that do have an "auto" feature that allows the machine to automatically adjust the amount of pressure as it senses how much it needs to overcome the obstruction. This is not BiPAP though, because the pressure is the same as the machine senses inspiration and expiration.

BiPAP is a preferred mode for various causes of respiratory distress as it lightens the work of breathing on a patient's respiratory muscles. It also improves the ventilation of the alveoli, improving the pO2 and pCO2 (in the ABG). BiPAP can be tried in an effort to avoid intubation in some cases, and sometimes the only option if the patient has an order for DNI (do not intubate). BiPAP also delivers pressure, but is programmed to give a higher level of pressure for the inspiratory phase and a lower level for the expiratory phase. The higher pressure during inspiration helps to deliver a higher tidal volume (volume of air during normal inspiration) and rest the respiratory muscles a bit. The lower pressure during expiration helps to keep the alveoli from "slamming shut" during expiration. It is like the PEEP in mechanical ventilation. It helps to keep more alveoi "recruited" because it takes more time and pressure to inflate a closed alveolus than a partially open one. (Think of trying to blow up a wet deflated balloon). It also reduces the damage to the alveoli caused by the more extreme tensile forces.

2. Paralytics (vecuronium, rocuronium, cistracuronium) are NOT used as a continuous drip routinely in the vented patient. They are used as boluses for rapid sequence intubation and may be very occasionally ordered as a PRN for the patient who becomes very agitated and bucks the vent with sedation already on board, and that is just to get the level of sedation back under control. Paralytic gtts are typically only used in cases of severe ARDS so that the body's oxygen demand is minimized as much as possible and the machine assumes all the work of ventilation. Another instance in which I've used a paralytic gtt is with brain dead "donor" patients that display spinal reflexes. And the purpose of paralyzing them is so that they don't scare and confuse the family into thinking that s/he is still alive.

Meds used for sedation for vented patient are generally continuous gtts and propofol is the most commonly used. Sometimes Versed, or Ativan is used instead, but that is generally the case when a patient's triglycerides are too high on propofol. PRN doses of Ativan or Versed are also sometimes used in addition to continuous sedation. Precedex can be used for patients that are being weaned to extubate since it can be continued after extubation.

Continuous narcotic infusions are are used in conjunction with sedation and are usually fentanyl or morphine with prn doses for procedures/breakthrough pain.

3. I'm not quite sure what you mean by commonly seen ICU problems. The resources that I use when I have questions are other nurses, physicians, RTs, peer reviewed journals.

 

[The right Path]

1) This thread contains some pretty useful info: http://forums.studentdoctor.net/showthread.php?t=498040

That was a good explanation. There was emphasis on not using sedation while on CPAP mode (mechanical vent). Precedex is specifically indicated in this case, and sometimes "we" (in our hospital) do use propofol and do CPAP mode. Case in point, one of my patients this past weekend was on 100mcg/h fentanyl and 50 mcg/kg/min of Propofol and flying on CPAP: RR 15-23, tidal vol 450-580's. Point being, there is a lot of variability in practice and many differing opinions!

2.) I could be wrong, but I think it has to do with, among other things, preventing muscle spasm that could dislodge the tube as well as other issues. Propofol and Etomidate are among the most commonly used sedatives, while opioids are used for analgesia. I'm not an expert, so please take this post with a grain of salt.

3.) http://www.learnicu.org/Pages/default.aspx may be a good resource.

I've only seen etomidate used for intubation, not for maintenance. I've never heard of muscle spasms dislodging the ETT. Not to say that it couldn't happen, but which muscle/s are we talking about here? However, patients can use their tongue to work out the ETT and I have seen that happen. Adequate sedation should be sufficient to keep that from occurring. I doubt that such an extreme measure as a paralytic should be needed. And I will say, too, that obviously, I am not the final authority on anything, let alone airway, ventilator management. Not a doctor, here, and not even in medical school either.

 

[Paseo Del Norte]

Etomidate is not an optimal medication for continuous infusion, that whole adrenal thing and all. Typically, sedation and analgesia is utilised to make the patient more comfortable and blunt all the negative effects associated with discomfort and anxiety. I cannot think of any other reasons beyond comfort and preventing all the potential negative consequences of pain and anxiety. The most common medications utilised in my area are Diprivan and morphine.

We typically do not want all of our ICU patients receiving neuromuscular blockers. We want spontaneously breathing patients and we want to get them off the ventilator and extubated if possible and as soon as possible. Clearly, neuromuscular blockade beyond the initial intubation is not going to help in achieving that goal. There are cases where we need to have sustained paralysis, however.

CPAP versus BiPAP; I will give you the ghetto version because it sticks in my feeble little mind.

CPAP is just like it sounds: Continuous positive airway pressure. Stick your head out of the car window on the highway (preferably while somebody else is driving) and you are essentially experiencing CPAP. You are delivering a continuous pressure throughout the inspiratory and expiratory phase of breathing.

BiPAP is similar to its name (bi-level positive airway pressure). Unlike CPAP, BiPAP delivers two different pressures. You receive an inspiratory pressure IPAP and an expiratory pressure EPAP. The inspiratory pressure is the bigger number and the expiratory pressure is the smaller number. You may see an order written as BiPAP 10/5. This means 10 of IPAP and 5 of EPAP. If the IPAP and EPAP were the same, you would have CPAP. Another ghetto way to look at the relationship is BiPAP is essentially CPAP with PEEP.

When and why to utilise one over another is a tricky subject. Both are effective and suffer from pitfalls. In addition, not every patient is a candidate or will benefit from non-invasive therapy. From the literature I have seen, CPAP may be slightly more effective. However, anecdotally I have found patients tend to tolerate BiPAP much better. During my RCP clinical experiences I have used both modalities and have found BiPAP to be more comfortable.

I know of some resources; however, if you are rotating as a physician, I am not sure how helpful nursing based sites will be? Clearly, these are my thoughts as a provider who is not a physician.

 

[proman]

http://www.ccmtutorials.com/ will help you immensely, and is at the appropriately level. The Society for Critical Care Medicine also has resources (LearnIcu.org is one).

 

[Dimoak]

I've only seen etomidate used for intubation, not for maintenance. I've never heard of muscle spasms dislodging the ETT. Not to say that it couldn't happen, but which muscle/s are we talking about here? However, patients can use their tongue to work out the ETT and I have seen that happen. Adequate sedation should be sufficient to keep that from occurring. I doubt that such an extreme measure as a paralytic should be needed. And I will say, too, that obviously, I am not the final authority on anything, let alone airway, ventilator management. Not a doctor, here, and not even in medical school either.

Etomidate is not an optimal medication for continuous infusion, that whole adrenal thing and all.

I wasn't referring to the maintenance in that case, but rather the initial intubation which occurs prior to the pt going on the vent. Since the OP also asked about paralytics, I wasn't sure if they were asking about the entire process or patients who are already being mechanically ventilated. Etomidate-induced adrenal insufficiency is actually fairly reversible, but I agree that etomidate is probably not the best thing to use, short of emergent intubations and patients with bp concerns. Once again, I'm far from an expert, but those are just my 2¢.

 

[jdh71]

1)What is the difference btwn CPAP and BiPAP? When would you use one versus the other?

The difference has been explained already.

You use CPAP for hypoxia and BiPAP for hypercapnia (or both, but if for both, just tube em). Get an ABG decide which variable the pO2 or the pCO2 needs fixin

2)Which medications are typically used when someone is on the vent for sedation and analgesia? Also, do you always need to use a paralytic such as rocuronium?

Sedation varies with institution by usually versed (midazolam) or ativan (lorazepam) are industry standard. Propofol for short term. Dexmedetomidine for difficulty in weaning with patients who FREAK waking up on the vent.

Analgesia is fentanyl. You may find a few stone age places that will still use morphine, but standard of care is really fantanyl.

Paralytics are not routinely used, mostly when you need to try some different vent techniques to improve oxygenation.

3)Are there any good websites or resources on commonly seen ICU problems?
Thanks

Google 'surviving sepsis campaign'. Shouldn't take you too long to read up on their recommendations. You'll feel more comfortable with these patients.

I'd also check out the newest ASPEN guidelines for nutrition in the ICU, most people don't know these that well yet, and you can make evidence based suggestions while on rounds that some people might not know yet.

 

[Paseo Del Norte]

I was just throwing the etomidate concept out as general knowledge for the OP.

Another good non-nursing resource I have utilised in the past is the ARDS network site: http://www.ardsnet.org/

 

[Bobblehead]

Just an editorial comment: BiPAP is a Respironics trademark although it's commonly also used to abbreviate to Bi-level Positive Airway Pressure. I've started to write BPAP into my reports just to be clear that I'm not endorsing Respironics although I do like some of their products.

 

[souljah1]

Another ghetto way to look at the relationship is BiPAP is essentially CPAP with PEEP..

Not true.

CPAP = PEEP.

BiPAP is PEEP plus IPAP.

CPAP or PEEP helps alveoli stay open (as well as soft tissue/large airways), which in turn can improve V/Q mismatch and consequently hypoxemia.

BiPAP helps with oxygenation (due to CPAP) and can also improve minute ventilation and help with hypercarbia.

 

[RT2MD]

There was emphasis on not using sedation while on CPAP mode (mechanical vent). Precedex is specifically indicated in this case, and sometimes "we" (in our hospital) do use propofol and do CPAP mode. Case in point, one of my patients this past weekend was on 100mcg/h fentanyl and 50 mcg/kg/min of Propofol and flying on CPAP: RR 15-23, tidal vol 450-580's. Point being, there is a lot of variability in practice and many differing opinions!

I agree 100% with your post. I wrote that other post 2 years ago and we didn't have Precedex at my institution at that point. We have had a lot of success with Precedex, and I have also been known to have a fair amount of propofol running during a spontaneous breathing trial... I just make sure that the patient is maintaining a good level of minute ventilation based off of what they had been doing on the vent. The point that I was trying to make was that you don't want to have the patient's respiratory drive knocked out during a spontaneous mode - people tend not to like that!

http://www.ccmtutorials.com/ will help you immensely, and is at the appropriately level. The Society for Critical Care Medicine also has resources (LearnIcu.org is one).

I also fully support that website. I think that it has a lot of great information on it.

Good luck! I think that the ICU is one of the most exciting places to work. I hope that you love it!

 

[Paseo Del Norte]

Not true.

CPAP = PEEP.

BiPAP is PEEP plus IPAP.

CPAP or PEEP helps alveoli stay open (as well as soft tissue/large airways), which in turn can improve V/Q mismatch and consequently hypoxemia.

BiPAP helps with oxygenation (due to CPAP) and can also improve minute ventilation and help with hypercarbia.

I agree that PEEP and CPAP are really the same at a fundamental and physiological level (Essentially work by increasing the FRC and potentially improving V/Q mismatch).

My point is that unlike CPAP where a "static" pressure is delivered throughout both inspiration and exhalation, you have both an inspiratory positive pressure and and expiratory positive pressure.

 

[Leverage]

The difference has been explained already.

Analgesia is fentanyl. You may find a few stone age places that will still use morphine, but standard of care is really fantanyl.

Fentanyl has a higher lipid soluability then morphine which accounts for its rapid onset of action...drug goes to vessel rich areas and easily passes blood brain barrier... but it's elemination half life on the other hand is longer then morphine. And once you gtts for greater than few hours you have pretty much saturated the body with fentanyl. Thus peripheral compartments will continue to spill fentanyl into plasma once gtts is off. this coupled with longer elimnation halflife makes me tend to order more morphine then fentanyl and if any componet of ARF/AKI I order hydromorphone gtts....

I guess i am wondering why fentanyl is standard

 

[jdh71]

Fentanyl has a higher lipid soluability then morphine which accounts for its rapid onset of action...drug goes to vessel rich areas and easily passes blood brain barrier... but it's elemination half life on the other hand is longer then morphine. And once you gtts for greater than few hours you have pretty much saturated the body with fentanyl. Thus peripheral compartments will continue to spill fentanyl into plasma once gtts is off. this coupled with longer elimnation halflife makes me tend to order more morphine then fentanyl and if any componet of ARF/AKI I order hydromorphone gtts....

I guess i am wondering why fentanyl is standard

I'm guessing because there is less associated hypotensive effects.

 

[PICUPNP]

In Pediatrics, our mainstay sedation is fentanyl or morphine and versed for continuous sedation. Propofol not widely used as continuous sedation in kids due to propofol infusion syndrome. We mostly use it to extubate kids who wake up like bears! Neuromuscular blockade not routinely used except in special circumstances like IICP issues, ECMO, ARDS(severe), etc.

 

[bulgethetwine]

In Pediatrics, our mainstay sedation is fentanyl or morphine and versed for continuous sedation. Propofol not widely used as continuous sedation in kids due to propofol infusion syndrome. We mostly use it to extubate kids who wake up like bears! Neuromuscular blockade not routinely used except in special circumstances like IICP issues, ECMO, ARDS(severe), etc.

PIS demonstrated to be vastly overblown. No evidence-based reason to avoid it, though usual caveat of long-term, high-dose avoidance is prudent.

Also, with national propofol shortage looming, probably prudent to use more morphine and versed in pediatric population where baseline hepatic and renal dysfunction is less than adults. However, in complex cardiac and congenital pediatric populations, MODS still an issue and versed can accumulate and cause problems - more frequently than the issue of PIS.