Re: Re: Oxygen Therapy/pulse oximetry

[Guest guest]

good points kenny. i did extensive research on pulse ox for a ce class i

presented at 2004 texas ems conference. i found that these machines are designed

for the in hospital environment and below ambient temp of 40 f or above ambient

temps of 100 f they lose accuracy. also very fast or very slow heart rates cause

them to be inaccurate. dont get me started on fingernail polish. i painted a

female paramedic nails 9 different colors and black was the only color which

affected the reading (dropped it from 99 to 92) As for EMI/RFI (radios.etc) the

other day i took a 18 y/o female to the hospital to was " texting " on her cell

and holding it in the hand which had the pulse ox probe. this dropped the

reading from 99 to 90. when i talked her into stopping (quite the trick) it went

back to 99.

jimmy davis

Kenny Navarro wrote:

>>> So we are going to " treat the machine and not the patient " ? <<<

WOW. How did you come to that conclusion based on the information I

provided?

Did you read the parts about " treatment guidelines " and " variation

depending on the circumstances encountered. "

What our guidelines encourage is treatment decisions based on

physical exams and the machines. Certainly you are not suggesting

that we rid ourselves of glucometers and sphygmomanometers and ECG

monitors and waveform capnographers.

>>> Everybody knows that Pulse Ox are mostly inaccurate in really

low down sick patients and doesn't give you enough information to

allow good decision making.<<<

Most manufacturers claim accuracy to be between within 2% and 4% of

actual values for readings above 70%.(1,2) During periods of

desaturation below 70%, the accuracy is substantially reduced.(3,4)

This seems to me an unimportant limitation, since most patients who

desaturate to such a low level are treated as aggressively as

possible, regardless of whether the true saturation is 40% or 60%.

I have never seen a hypoxic patient with a normal pulse oximetry

reading. The above-mentioned studies (and others) seem to support my

experiences.

Interestingly, one researcher has successfully demonstrated that the

differences in pulse oximeter readings between the right hand and one

foot could be used as a screening tool to aid in the diagnosis of

critical congenital heart disease.(5) Now, that is impressive

accuracy!

With Love,

Kenny Navarro

Dallas

References

1. Tobin MJ. Respiratory monitoring. JAMA 1990;264(2):244�251.

2. Severinghaus JW. History and recent developments in pulse

oximetry. Scand J Clin Invest Suppl 1993;214:105�111.

3. Faconi S. Reliability of pulse oximetry in hypoxic infants. J

Pediatr 1988;112(3):424�427.

4. Severinghaus JW, Naifeh KH, Koh SO. Errors in 14 pulse oximeters

during profound hypoxemia. J Clin Monit 1989;5(2):72�81.

5. de Wahl Granelli A, Mellander M, Sunneg�rdh J, Sandberg K, Ostman-

I. Screening for duct-dependant congenital heart disease with

pulse oximetry: a critical evaluation of strategies to maximize

sensitivity. Acta Paediatr. 2005 Nov;94(11):1590-1596.

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