[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Resp. and ECG- new question [HAPP-L]
I am on my 4th semester with this exercise, and each time I revise the
canned data sheet, and each time I discover there is still something not
addressed. Biopac is wonderful, but this particular exercise is a mess in
the sense Ken & I and others have noticed - it looks like the person who
designed the data sheet is not the person who designed the protocol.
One other comparison that the instructions tell the students to do, but
are not discussed later, is differences between DEEP breathing and NORMAL
breathing. Please hapsters with good ECG background, how should these
ECGs compare? Also, the difference between supine and sitting - will
changes between insp. and exp. be more pronounced? How large should the
differences be in HR between supine and sitting, regardless of insp. &
exp.? The data analysis takes a long time, and I've wondered if it is
worth making all these comparisons - if the difference if slight enough to
be unreliable in a student lab setting, I'd rather not have them do it
all.
Ken, in the instructions students are not told to keep track of insp. and
exp. during supine recording, but they are asked to distinguish these
during data analysis. Also, some of my students placed the markers but
forgot to type i or e, so this is worth a reminder. If you are re-writing
the instructions, be very careful about these and other problems. I think
it should be like this (I am writing from home, the duration of the
records are from memory, change them as necessary):
1) supine, normal breathing, mark insp and exp (1-20 sec)
2) supine, deep breathing, mark insp and exp (21-40 sec)
3) sitting, normal breathing, mark i & e (41-60 sec)
4) sitting, deep breathing, mark i & e (61-80 sec)
5) immediate post exercise (81-140 sec)
In the data analysis, I ask them to compare early post-exercise to the end
of the record, and calculate rate of recovery. I only have them complete
the detailed table of durations, segments, and intervals, on the supine
recording - the instructions do not specify if these measurements should
all be made on insp. or exp.
On the data sheet, I photocopied the tables several times, then made a new
data sheet so each posture has the tables for insp. & exp., then
post-exercise has a table for early and late. This week I'll be trying
again - I always manage to fix one thing but leave something else
un-fixed. Good luck, and if you want, I'll send you my latest version of
the data sheet - just ask.
Dear HAPSters,
Can anyone help me out here?
I am about to run the Biopac electrocardiography exercises for the
first time, and I am wondering about the physiological relationship
between breathing and the ECG. In the "ECG I" chapter, there is an
experiment in which the students are to observe and measure changes in
the ECG during deep inspiration and expiration. However, in the data
analysis section and lab report questions, there are no further
references to this, much less any physiological explanation of why the
ECG should change during deep breathing -- the whole phenomenon just
seems to disappear from further consideration in the lab manual and in
the students' writeup. Nor do I find any discussion of the effects of
respiration on the ECG in Guyton & Hall, Berne & Levy, Harrison's, or
Cheitlin's Cardiology, nor was the vertebrate comparative physiologist
in my college department able to help. (There's only one to consult;
we're not a large department.)
I offered him the conjecture that the thoracic pressure changes during
respiration may affect the arterial baroreceptors and thus activate
transient baroreflexes, to be reflected in changes in heart rate. He at
least thought that was a reasonable hypothesis. But the screen capture
in the Biopac lab manual shows (but does not discuss) what appear to
be changes in voltage rather than heart rate. My feeble intellect
can't imagine why the respiratory rhythm would cause voltage changes
in the ECG, or what that would mean physiologically.
I am running this in my two lab sections at 1:00 (EST) Mon & Wed this
coming week. I'd be very appreciative of whatever explanations anyone
can offer before then, but even afterward, it would be useful to have
more insight into this for the benefit of my future classes. I hate
just exhorting students to measure something and compare numbers with
no insight into what the numbers and comparisons mean.
Many thanks for any help you can offer.
Ken
=========== HAPS WEBSITE AT http://www.hapsweb.org ======
**** To UNSUBSCRIBE****
send e-mail to HAPP-L-request@xxxxxxxxxxxxxxxxxxxxxxxxx
In the BODY of the message at the beginning of the
first line put ONLY the single word UNSUBSCRIBE
----------------------------------------------------
The mail being expressed is the responsiblity of the
original author.HAPS and Imperial Valley College, trustees,
administration, faculty, etc.disclaim any responsibilities.