I was interested in this issue too, coming from an adult ward (where
everyone was irradiated) to a paediatric one (where it took heaven and
earth to get x-rays near kids). pH testing was the order of the day. I was
convinced it would be wrong, and did a Medline search, finding
Neumann MJ, Meyer CT, Dutton JL, Smith R. Hold that x-ray: aspirate pH and
auscultation prove enteral tube placement.J Clin Gastroenterol 1995
Jun;20(4):293-5
(Medline
http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=7665817&form=6&db=m&
Dopt=b)
It's not perfect - and a bigger, more rigorous study would be nice - but
this paper implies pH testing works for identifying gastric placement and
auscultation is worse than guesswork!
Yours,
Bob
(ps - CAT available on request)
>>--- snip ---
>>
>>It is the practice in the U.S. to just auscultate over the stomach, while
>
>>air is injected through the NG tube. No Xray or pH testing is done, unless
>
>>
>>one is attempting duodenal placement, then Xray is used. I am not aware of
>
>>
>>any centers using pH testing.
>>
>>Daniel Sontheimer, M.D
>>Spartanburg Family Medicine Residency
>>Spartanburg, SC 29303
>>Email: [log in to unmask] <mailto:[log in to unmask]>
>>
>>
>> -----Original Message-----
>> From: Mark Newman [SMTP:[log in to unmask]]
>> Sent: Friday, December 17, 1999 12:20 PM
>> To: [log in to unmask];
>>[log in to unmask]
>> Subject: Is this NG feeding tube in the correct place
>>
>> Dear colleagues
>>
>> Some nursing colleagues who I have been working with on
>> improving our EBP skills came up with the following EBP question.
>>
>> In patients who are being fed by NG tube how good is pH testing at
>> determining whether the tube is in the Stomach or in the lungs ?
>>
>> Practice at the hospital where they work is currently that the
>> position of all tubes when inserted is checked by a pH test and
>> also by X-Ray before feeding is commenced. They came up with
>> the following observations about this:
>>
>> 1) It seems strange to bother with the ph test if you are going to
>> x-ray the patient anyway.
>> 2) Patients often pull on the tubes or the tubes get pulled and
>> therefore moved and often nurses just push the tube back and do a
>> ph test only.
>> 3) If everytime patients pull on tube need to get it re x-rayed this
>>
>> will results in patients having a lot of x-rays, and will be quite
>> expensive
>> 4) Doing a only a pH test on insertion if sensitive enough would
>> reduce patient exposure to radiation and save a considerable
>> amount of resources
>>
>>
>> My recommendation to them (I hope its the correct one ) was that
>> they should treat this as a diagnostic test question. The evidence
>> they would need to find would therefore be a study whereby a group
>> of patients with ng tubes had the position checked by ph testing
>> (by your average nurse in real clinical setting (usually visual
>>reading
>> of test reagent stick)) and by the gold standard (x-ray) and then
>> the sensivity and specificity, Pos predictive value etc. etc. for ph
>>
>> testing could be established
>>
>>
>> They have been searching for this kind of study and no luck yet
>> (have found a lot of work by Norma Metheny and Colleagues from
>> St louis University which we are ploughing through but does not
>> seem to answer this particular question )
>>
>> q.1 if anybody else knows of any other evidence sources for this
>> would be grateful to hear about them
>>
>> reading so far has thrown up lots of questions about the various
>> methods of ph testing. Currently in this hospital they are using
>> litmus paper - Some of the evidence we have found on this
>> suggests that litmus paper is not good at discriminating between
>> gastric fluid and lung fluid because it can change colour for both
>> because of ph level at which it is sensitive (sorry can't remember
>> what this is at the moment) But evidence is not that good quality
>>
>> q2. Anybody know of any other evidence on this
>>
>> I have technical question about such a study. The risk of the tube
>> being in the lungs undetected appears to be quite small (4/605 in
>> one study). It would also be unethical if not impossible in practice
>>
>> do a study where tubes were deliberately put into the lung as well
>> as put into the stomach.
>>
>> q3. If in a study all the tests were on ph testing where all the
>>tubes
>> were in the stomach would this answer our question - if not what
>> else could researchers do?
>>
>> The risk of the tube being in the lungs undetected appears to be
>> quite small, However in the literature it seems to be regarded as
>> absolutely imperative that this is established before the feeding
>> started due to what are described as the grave consequences of
>> starting feeding with the tube incorrectly positioned.
>>
>> q4. Does this mean that only a test which is 100% sensitive (or
>> whatever current gold standard level is - presumably x-ray is very
>> near this) is acceptable ?
>>
>> That will give you something to chew during the festive season.
>> Look forward to hearing your replies which I will summarize for
>>list.
>>
>>
>> seasons greetings
>>
>> mark
>> ***PLEASE NOTE ARCHWAY PHONE NUMBER CHANGED AGAIN*****
>>
>> Mark Newman
>> Senior Lecturer:
>> School of Health, Biological & Environmental Sciences (HeBES)
>> Middlesex University &
>> Barnet & Chase Farm Hospitals NHS Trust
>> Furnival Building, Archway Campus
>> Highgate Hill
>> London N19 3UA
>> Tel: 0181 362 5000 (ex2281) or 0181 366 6600 ex 5775
>> Fax: 0181 362 6299
>> E-Mail: [log in to unmask]
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
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