Nitrogen Wash Out

[canoehead]

I need to give an inservice to the med/surg staff on assisting with intubations. Can anyone tell me the reason for "nitrogen wash out" pre intubation?

When I was taught to assist they said to remove the pillow, but I see on several internet sources they recommend leaving it under the head and neck. Has that changed, or did I just learn wrong?

If you have any points that should be emphasized during my inservice I'd love to hear them. Pet peeves, or things that nurses don't normally know that they should.

Thanks for your help.

[mced]

Suggestions on alternatives that might have worked for the next time this happens? I totally HATE not having an airway- we spent 2 hours. pH7.04 and PCO2 162 when he left- he seemed to be exhaling into his belly! Sats stayed in the low 90's with bagging so I certainly got a demonstration of how the SpO2 can be misleading that night.

What about a retrograde intubation?

[berry]

I think a combitube may be useful to keep around. Cheap, decreased need of skilled providers, a better alternative to repeated direct attempts.

[vampiregirl, BSN, RN]

Oh, I forgot to ask...our CO2 detector turned color confirming ETT placement, but the ETT was definitely in the esophagus per breath sounds and dropping sats. How much can we rely on the CO2 detector alone- not at all? If so then what is the point of using it?

Was it was one of the disposable CO2 end tidal detectors? If so, some of them are only accurate for so many minutes (I think the ones I've used on the ambulance are only good for 5 minutes according the itty bitty type in the manufacturer's instructions).

[tridil2000, MSN, RN]

Yeah, I would think too, but apparently not- hence the inservice.

Last night we had a 400lb man with no neck, and very edematous CHF come in with almost no air entry. Attempted BiPAP but the straps on the masks didn't fit because he was too big. Rapid sequence intubation- the ER doc and one of our most experienced EMT's attempted intubation unsuccessfully. Respiratory was called in at that point, and anesthesia. We are a small hospital so both were about 30 minutes away. Let the man wake, but he was still unable to move air and he was fighting us so put him down again and bagged. His belly got double in size and tight as an almost bursting basketball. NGT was passed x3 without success. LMA sizes 4 and 5 were both too small to prevent air leakage and sats dropped with those attempts. We didn't cric because the doc felt the landmarks were invisible (and we do those like, once a century). Anesthesia came in and attempted all of the above, but we ended up transporting him (30 minute ride) with bag-valve mask to a higher level facility where ENT trached him.

Suggestions on alternatives that might have worked for the next time this happens? I totally HATE not having an airway- we spent 2 hours. pH7.04 and PCO2 162 when he left- he seemed to be exhaling into his belly! Sats stayed in the low 90's with bagging so I certainly got a demonstration of how the SpO2 can be misleading that night.

thank god these awful cases are few and far btwn.

i have to ask though, what was the primary causes for his dyspnea? was he full of rales or tight? could he have rec'd a neb and some solumedrol and/or lasix/nitro?

i would think addressing the cause, whether heart failure or copd, would really have help him during that time frame.

when these heavy weights come in they sure do present many challenges. i can't believe your er dr couldn't get this airway though. perhaps when another large pt comes in your anesthesia on call chould be notified once the medics in route notify you. at the very least, they can be literally ready to come in the minute you really need them.

i'm afraid there will be more cases like this rather than less.

i have a ? regarding nitrogen wash out myself, if anyone is interested. i thought it was not a very good thing... as it is nitrogen that helps keep the alveoli open?

[dfk, RN, CRNA]

Oh, I forgot to ask...our CO2 detector turned color confirming ETT placement, but the ETT was definitely in the esophagus per breath sounds and dropping sats. How much can we rely on the CO2 detector alone- not at all? If so then what is the point of using it?

remember too that 'traditionally', once the ETT is placed (at bedside), the ETCO2 should be monitored for roughly 5 minutes to eliminate esophageal intubation, which i'm sure rarely occurs, as i have never seen it with all of my bedside intubations, but that's what is "taught" for CCRN and the like.. now, auscultation and observation are relatively safe for the beginning confirmation.. ETCO2 monitor is by far definitive, but rarely if ever at bedside in icu with a vent.. cxray not always readily available either.. what i'm trying to say is not to ALWAYS as a rule believe the CO2 detector to confirm, as gastric CO2 can subside for several minutes.. again, you are taking into account several factors that point to proper ETT placement such as improved sats and increased HR, should it have vagaled from apnea.. anyway, just another thing to keep in mind, whether "common" in practice or not...

[dfk, RN, CRNA]

partial non-rebreathers retain CO2. non-rebreathers have a valve that will not allow CO2 to be rebreathed.

actually, NRBs are considered PRBs... since a complete fit rarely occurs, outside air is admixed.. what my point was is that exhale is often not forceful enough, especially if they are failing, so there actually is some CO2 retention.. that is why you would administer this type of therapy to COPDers and the like..

[canoehead, BSN, RN]

Our guy did get Lasix, but not Nitro for CHF, but only put out about 100cc while he was with us. We have no combitube- although it sounds like something that would have helped, and as for fiberoptics- ummm, we just got computerized last month and you want cutting edge technology? Honey, I want a wheelchair accessible bathroom, everyone knows a good BM beats a good airway anyway.

mced, a retrograde was not done by the ER doc because of the lack of landmarks, and lack of experience. We were able to keep sats up with bagging, and anesthesia was on the way in. They are about 30 minutes away at best. Thinking about it afterward, surely we could have put a 14G iv in his trachea and bagged that, but would have been an improvement, or just another chance to make a mistake?

Someone mentioned putting an LMA in and then using it to intubate...so you occlude the esophagus and then take a small ETT, put it in through the LMA? Then deflate the LMA and pull it oput over the ETT? What size ETT would we have ended up with, and is the LMA a good guide into the trachea, or is a blind intubation more likely to be successful?

[deepz]

That reference was to the Intubating LMA, a device specific to that purpose, with its own obturator and ET accessories in the kit. Handy item. In the right hands, slick as snot on a doorknob.

d

[tridil2000, MSN, RN]

thank god these awful cases are few and far btwn.

i have to ask though, what was the primary causes for his dyspnea? was he full of rales or tight? could he have rec'd a neb and some solumedrol and/or lasix/nitro?

i would think addressing the cause, whether heart failure or copd, would really have help him during that time frame.

when these heavy weights come in they sure do present many challenges. i can't believe your er dr couldn't get this airway though. perhaps when another large pt comes in your anesthesia on call chould be notified once the medics in route notify you. at the very least, they can be literally ready to come in the minute you really need them.

i'm afraid there will be more cases like this rather than less.

i have a ? regarding nitrogen wash out myself, if anyone is interested. i thought it was not a very good thing... as it is nitrogen that helps keep the alveoli open?

answered my own ?

The effects of an increased FIo2 and nitrogen washout are important to consider. The higher the concentration of oxygen in the alveoli, the lower the concentration of nitrogen. Nitrogen accounts for 80% of alveolar gas. Because nitrogen is inert, it merely occupies space, holding alveoli open as O2 and CO2 are rapidly exchanged during each breath. When nitrogen is washed out during O2 breathing, alveoli tend to decrease in volume or collapse altogether with each breath. Major atelectasis can occur with just a few minutes of 100% O2 breathing. In one study,2 chest CT scans during O2 breathing demonstrated major atelectasis occurring within minutes [see Figure 8 -- omitted]. Because a high FIo2 is commonly (and correctly) used during anesthesia with inhalational agents, it is important to minimize the risk of postoperative atelectasis through frequent recruitment of collapsed alveoli by inflation to total lung capacity and restoration of alveolar nitrogen at the end of the operation

http://www.medscape.com/viewarticle/535472

[canoehead, BSN, RN]

What!!!? No one ever told me that one. So are you saying that if I use 100% O2 on someone in severe respiratory distress I could be contributing to the problem? Just so I express myself accurately I am about to go off the deep end with this information. Someone please tell me that it is not significant unless long term, or something...

The only cautions I've heard of with O2 have been with premature infants and COPD patients.

[berry]

What!!!? No one ever told me that one. So are you saying that if I use 100% O2 on someone in severe respiratory distress I could be contributing to the problem? Just so I express myself accurately I am about to go off the deep end with this information. Someone please tell me that it is not significant unless long term, or something...

The only cautions I've heard of with O2 have been with premature infants and COPD patients.

Prolonged periods of exposure to a FiO2 > .8 leads to atelectasis as nitrogen remains replaced by O2.

Obviously if a patients clinical s/s and abgs indicate more O2 is needed do not hold back, but after they are intubated you can increase PEEP and decrease FIO2 to obtain respectable abgs. Some less aggressive steps could include a trial run on CPAP or BiPAP.

[dogbone]

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