Sunday, February 05, 2006

Vent weaning and severe COPD

AK submits the following:

A patient with an FEV1 of 400 cc, steroid and O2 dependent, vented for 55 days after respiratory arrest due to pneumonia. He's a former smoker, relatively young (mid fifties), and the workup for his early onset COPD was unrevealing. He does not have any other significant comordities outside of the psych issues you'd expect after two months on a vent. He's trached, but weaning has been very difficult. He generally fails weaning attempts due to a shallow and rapid breathing pattern.

I was wondering if anyone has experience with weaning in patients undergoing prolonged mechanical ventilation. Hoping to generate some discussion about the slow SIMV wean published by Scheinhorn, or the use of NIPPV to wean patients with a trach. Quinnell's article in the January Chest showed a surprisingly high success rate with a mean FEV1 of approximately 600 mL.

Any other ideas for weaning in this type of patient population?

9 comments - CLICK HERE to read & add your own!:

Jeff H said...

Thanks for the case, Aran. I think this raises a very important (and frustrating) aspect of care that we have not addressed on this blog.

My personal experience with long-term weaning is limited; however, I have the following questions:

1. When this patient fails due to to rapid and shallow breathing, does he appear to be in distress (i.e. diaphoretic, tachy, mental status changes, respiratory acidosis).

2. What are the patient's muscle forces--is it possible that there is a component of ICU neuropathy/myopathy that will just take time?

3. Is there a possibility of occult cardiac ischemia, which is an underrecognized cause of Failure-to wean.

Presuming these (and other common causes of FTW) have been addressed, I would favor the NIPPV method-although I agree that the success rate in the recent Chest paper seems a bit too good to be true! This may even be a situation in which a reasonable goal may be to get the patient to nocturnal ventilation at home.

Finally, although not related to weaning, this relatively young former smoker may be a candidate for lung transplantation. Given recent changes in organ allocation (need-based, not based on time accrued since listing), it may be reasonable to look into that possibility, as it may be the "best" longer-term option.

I look forward to seeing what more of our colleagues have to say about long-term weaning.

Baleeiro said...

We are in the TOB belt here in TN so we see alot of COPD and have had quite a few recent cases of true failure-to-wean. We have worked closely with one of the local DME/home respiratory companies who owns a long-term vent facility with reasonable success. A handful of those ended up going home on a vent/BiPAP via the trach and were weaned veeeery slowly (over several months and one of them over a year) with family involvement. Most of these were done with a similar SIMV protocol.
It is a very tough problem and one of these above mentioned patients decided she no longer needed nocturnal BiPAP, came back in hypercapnic failure again and will be going home on a home vent starting it all over again...

Baleeiro said...

Jeff H's points are obviously very good and well taken. In addition to myopathy and heart disease I will also add thyroid eval and nutritional support since many of these patients have COPD cachexia.

Anonymous said...

i would ask if the patient had a CT scan to see if he has a predominantly apical disease..if it is the case ..the patient may benefit from volume reduction is being done these days endoscopically although it is still under the realm of research but these are things to considert

Jennings said...

I agree with Jeff H; critical care polyneuropathy is an underrecognized cause of many failure-to-wean patients. Studies evaluating the different weaning strategies for the long-term patient (i.e. at a chronic facility) are limited because there are so many confounders that isolating the weaning protocol variable is near-impossible. The interpretation of these srudies (mostly observational) is essntially fruitless when we consider the heterogeneity of quality of care among these different chronic care facilities. I would bet that the type of wean (i.e. slow SIMV, etc) is less important than the underlying problem (i.e. underrecocnized CC polyneuropathy, ischemic cardiomyopathy, malnutrition, etc).
Although some of the surgical options mentioned here (transplant, lung volume reduction) are attractive, I doubt any surgeon would touch a patient who has been on a vent for 55 days.

Jeff H said...

Surprisingly, transplant surgeons are now considering patients who are on a vent, and are considering some FTW patients. Granted, it's rare--the patient would need to have single-organ disease, a lack of infectious complications (such as VAP...), and even then it's a bit of a long shot. However, it is not outside the realm of possibility, and it sounds as if the current patient being presented is the kind of patient for whom a transplant in these circumstances is conceivable.

That said, I don't know of any data on outcomes of lung transplant for patients with FTW!

AK said...

Thanks for all the input. To respond to some of the questions/comments:

- Failed weaning attemps are charatcerized by tachypnea, severe anxiety, and respsiratory acidosis. Have tried opiates +/- benzos to try to alleviate anxiety or dyspnea. Have not tried nebulized Lasix.

- Thyroid function is normal.

- Based on albumin and prealbumin, nutritional status is not optimal, depsite getting adequate tube feeds from day one. I just tried switching him to a low carb enteral formulation. Getting desperate.

- TTE is pending, although at this particular LTAC, it's nearly impossible to get an echo to coincide with a weaning attempt.

- He declined transplant or lung volume reduction (prior to this episode on the vent).

- CC polyneuropathy/myopathy is an interesting thought. He has grossly intact motor strength. Say an EMG or biopsy were abnormal - could you do anything about it?

Jeff H said...

As far as I know (last time I looked was about 6 months ago), there are no treatments for critical care neuropathy/myopathy other than time. It sounds as if all the right bases have been covered. If the failure of the weaning trials is associated with respiratory acidosis, then I think that the patient's physiology just isn't up to the task of maintaining ventilation. I'd continue to persue the cardiac ischemia route as you are, and then it may just be time to commit to chronic MV.

Certainly, a low-carb/high lipid and protein diet may help some, but the poor nutritional status may be as much a reflection of the end-stage disease as a "cause" of failure to wean.

Anonymous said...

My mother has advanced COPD and about to fail her second attempt at vent weaning. I am a psychiatrist so not much of an expert in these matters. Of course I have been reading a lot on end-stage COPD these days, but reading is not enough. I wonder if you could help me. I was asked this afternoon whether I wish my mother to be put back on MV. The doc said the prognosis is poor anyway, so she is likely to die on MV, which he said is not something he would recommend. This in his opinion would only add to her suffering. My question is, is there a possibility that she might succeed another weaning trial, and second – is there really no means of relieving the pain and distress while on MV? NB. We are in a hospital in Poland and protocols in use here may differ from those in the US. So far my mother has received no palliative treatment whatever for her symptoms despite my suggestions.