Cardiovascular Lab Protocol 2013 (1)

8/16/2019 Cardiovascular Lab Protocol 2013 (1)

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Study sources for lab work and the pre-lab examination

1. Lectures (hemodynamics and heart mechanics)

2. R.M. Berne, M.N. Levy, B.M. Koeppen, B.A. Stanton Physiology , Mosy

!th "d pp. 2#!$2#%, &1&$&1', &1$#

#th "d. p. 2'*$2*1, &21$&2#, &&+$&&

Instructions for the lab report

he -oo/in0 parts shoud e incuded in the a report

a. ive rie- ans/ers to a the 3uestions that appear in the protoco (numered 1$1#).

. Attach the printouts and 0raphs you are re3uested to produce in the protoco.

Lab objectives

1. Bood pressure measurement.

2. Revie/in0 the cardiac cyce and studyin0 the time reationship et/een eectrica and

mechanica events in the heart.

&. Learnin0 the -actors that determine ood pressure (computer ima0in0).

Introduction

4n this a, /e /i earn the techni3ue -or measurin0 ood pressure5 /e /i discuss the main

events occurrin0 durin0 the entire cardiac cyce5 /e /i cari-y the reationship et/een cardiac

output, arteria ood vesses resistance (and their eastic properties) and the systoic anddiastoic ood pressure.

Exercise 1 - Blood pressure measurement by a sphymomanometer and a stethoscope

Instrumentation

he sphy0momanometer is a /ide cu-- that is /rapped around the arm and in-ated /ith a

manua ruer pump, /hie the pressure in the cu-- is read y mercury manometer. A suitae

scre/ permits pressure reease at a controed rate. he pressure in the cu-- (the one that is read

y the manometer) is the pressure actin0 radiay on the rachia artery o- the arm. he

stethoscope enaes you to hear sounds connected /ith the periodic openin0 and cosin0 o- the

rachia artery. hese sounds are caed Korot6o-- sounds.

Cardiovascular Laboratory

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!he blood pressure measurement method "as recommended by the #merican $eart

#ssociation "1%&&'

1. Ma6e sure that the su7ect did not smo6e or eat -or at east &+ minutes e-ore the test.

2. "nsure that the su7ect is sittin0 com-ortay and rea8in0 -or at east 1+ minutes e-ore thetest.

&. "8pose the su7ect9s arm. (Appyin0 additiona pressure throu0h the shirt seeve may cause

an inaccurate evauation).

. :ind the auscutation point y sensin0 the rachia puse at the cuita -ossa.

!. rovide support -or the eo/ o- the tested arm and ma6e sure that the auscutation point is

paced on the eve o- the su7ect9s heart. (Measurin0 the pressure /hie the arm is not

ocated at the eve o- the heart /i add or reduce hydrostatic pressure eadin0 to inaccurate

evauation).

#. ace the manometer at your eye eve to insure com-ortae readin0.

%. ;rap the cu-- around the arm ti0hty ut /ithout pressure. he o/er ed0e o- the cu-- shoud

e at east 2 cm aove the auscutation point.

'. 4n-ate the cu-- /hie -eein0 the rachia (or radia) puse manuay5 oserve the pressure at

/hich the rachia (or radia) puse disappears $ this pressure is cose to the systoic

pressure. 4n-ate the cu-- 1+$&+ mm


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1()) &) 1*+ )&)1*)

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:utter

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Korot6o-- sounds

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:utter

קורוטקוף קולו

4n case there are di--icuties /ith hearin0 the Korot6o-- sounds, as6 the su7ect to raise his

hand e-ore and durin0 the in-ation o- the cu-- and to o/er it ac6 immediatey /hen the

reease o- the pressure starts. ou can try to measure the pressure on the other arm as /e.

Korot6o-- sounds appear /hen the vaue o- the pressure appied y the sphy0momanometer cu--

on the artery is et/een the ma8ima ood pressure (the systoic) vaue and the minima (the

diastoic) vaue.

!he followin diaram describes how these sounds are created+

1. ;hen the air pressure in the cu-- is hi0her than the systoic pressure in the ood vesse $ the

ood vesse is oc6ed, so ood does not -o/ and no Korot6o-- sounds are heard.

2. ;hen he air pressure in the cu-- is o/er than the systoic pressure ut hi0her than the

diastoic pressure, ood passes in units (partia or not homo0eneous ood -o/) and causes

the -utter phenomenon and turuent -o/. As on0 as ood continues to pass in units,

Korot6o-- sounds are heard.

4n this situation, a pressure /ave reaches the oc6ed artery and opens it. As on0 as the pressure

in the ood vesse is hi0her than the pressure appied to the cu--, the vesse /i remain open.

he -orce o- the pressure /ave is appied to the unit o- ood that is passin0 /hie the ood

vesse is open. =ue to the e--ect o- this -orce, the unit o- ood is acceerated and the -o/

ecomes turuent. At a hi0h speed, the 6inetic component o- the

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ood pressure increases stron0y at the e8pense o- the atera component o- the pressure

(Bernoui e--ect). 4n this situation, the artery /as coapse internay. A-ter the portion o- ood

has passed, the eastic /as o- the artery return to their previous state. hese repeated

movements o- the artery /a, caed C-utter,C and the turuent -o/ o- the ood 0enerate

sounds, /hich /ere -irst descried y Korot6o-- in 1*+!.

he -orce that acceerates the unit o- ood and the 3uantity o- ood passin0 aon0 the artery

chan0es durin0 ood pressure measurement. A this a--ects the acoustica characteristics o- the

Korot6o-- sounds the sounds chan0e in intensity and -re3uency durin0 the test. :ive types o-

Korot6o-- sounds, /hich chan0e durin0 ood pressure measurement, can e distin0uished

ype 1 D appin0 sounds that appear /hen the pressure in the cu-- e3uas the systoic pressure.

hese sounds are /ea6, ut distinct, and their intensity increases as air pressure in the cu--

decreases.

ype 2 $ Murmurin0 sounds, /hich appear immediatey a-ter the end o- the ype 1 Korot6o--

sounds.

ype & $ he stron0est and most distinct sounds that can e heard durin0 ood pressure

measurement.ype $ Mu--ed /histin0 or o/in0 sounds.

ype ! $ Sounds appearin0 /hen the pressure in the cu-- e3uas the diastoic pressure.

As mentioned aove, the appearance o- sounds indicates the vaue o- the systoic pressure, and

mar6s the moment that the pressure /ave reaches the oc6ed artery.

&. ;hen the air pressure in the cu-- is o/er than the diastoic pressure in the ood vesse $

ood -o/s -reey, no sounds.

1). For your lab report please prepare distribution histograms for:

a. Systolic blood pressure

b. Diastolic blood pressure

c. Mean blood pressure

Use the data from your lab class. Do your curves fit the distribution curves in general

population? !plain "hy?

#). $hy should the sub%ect&s position during the test be stated? 's it also important to

report ho" long before the test the sub%ect changed his position? !plain.

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Additiona re-erences re0ardin0 ood pressure measurement

1. Anderson :.=., ?unnin0ham S.., Maoney E.. Indirect blood pressure measurement+

a need to reassess (m *rit *are 1**& 2()2%2$*.

2. Bates B., Bic6ey L.S.,


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• Ma6e sure that a cear recordin0 is otained on every channe. Note the shape o- the

si0nas and their mutua timin0.

9hen everythin is clear: start the procedure;

• 4n-ate the cu-- unti the voume puse in the -in0er disappears (appro8. 1!+ mm


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Exercise


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atrium is very o/ compared /ith the arteria pressure, and, conse3uenty, it can e i0nored in

the e3uation. hus, the arteria pressure is very cose to the product o- ?H and SGR.

4n this e8ercise, t/o /indo/s appear Monitor P a /indo/ -or recordin0 the arteria and venous

ood pressures (ri0ht atrium pressure), and hysioo0ica =ata P a /indo/ /ith a tae o-

physioo0ica vaues.

1. 4t is o-ten stated that the mean ood pressure can e evauated -rom the -oo/in0 e3uation

- mean - dia > 1;8--

--


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&. Start in-usion o- phenyephrine. (henyephrine activates 1 receptors and causes contraction

o- the smooth musce in the ood vesse /as.) :or the purpose o- in-usion, seect the =ru0

and :uid 4n-user ine in the oos /indo/, press T to add a medication, add phenyephrine

y continuous 4G, and set the in-usion rate at 1+ O0U60Umin, y usin0 the e-t arro/. Start

in-usion y pressin0 the red circe unti you reach 1+++ O0U60. Stop simuation, y pressin0

Simuation $Q Set Simuation Speed $Q aused, and record the data otained in the tae.

#) +o" did -henylephrine affect the systemic vascular resistance


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c; Shape and nature of the pulse wave

=urin0 the systoe, ood is in7ected into the arteries. he ood vesse /a is stretched and

stores part o- the pressure ener0y. =urin0 the diastoe, this ener0y is returned and 0enerates ood

-o/ in the period /hen the ventrices don9t cause any ood -o/. his aiity o- the arteries to

e8pand, and to store ood and ener0y, is due to the response o- the arteria system. he overa

e--ect o- the arteria response is that -uctuations in ood pressure et/een hearteats are

reduced, and the ood -o/s amost continuousy in the capiaries.

o start this test, oad a ne/ physioo0ica state, y pressin0 :ie $Q Load hysioo0y State $Q

;ave-orm.sim. A /arnin0 that the e8istin0 /indo/s /i e deeted appears on the screen. ress

es.

/o ne/ /indo/s shoud appear on the screen a /indo/ -or recordin0 the puse /ave in

di--erent areas, and a /indo/ /ith a tae -or physioo0ica vaues.

( mm$ * mm$ Baseline

"-(mm$'

/sys/dia/mean

/ulse pressure

"//'

Stroke volume

"S='

/ra

1. :i in the aseine coumn in the tae, -rom the /indo/ o- physioo0ica vaues.

2. o reduce the stro6e voume, increase the e8tracardiac pressure to 2 mm


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!. 4ncrease the sie o- the Aortic and :emora ressure /indo/, in order to see in detai the

pressure in the aorta and the -emora artery.

Note that the shape o- the /ave in the aorta sho/s a deep dicrotic notch, /hie the -emora artery

sho/s ony a de-ection point, /hich re-ects cosin0 o- the semi$unar vave. rint the recordin0,

y seectin0 the /indo/ and pressin0 the printer icon.

$ Hn the printed sheets, mar6 the dicrotic notch, systoic pressure and diastoic pressure.

Note that there is a time di--erence et/een pressure uid$up in the aorta and pressure uid$up

in the -emora artery. By reducin0 the time a8is (seect time a8is, ma6e a ri0ht cic6 and set the

desired time period), try to estimate the ma0nitude o- this time di--erence.

1) $hat is the time difference bet"een the appearance of the pressure "ave in the aorta

and the appearance of the pressure "ave in the femoral artery? 'n your opinion "hat is

the cause of these time differences?

11) +o" do the structures of the pressure "ave and the pulse pressure change "hen "emove to"ards the periphery? $hich parameter hardly changes?


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#ppendix 1

/atho-physioloy of hypertension

oday, hypertension is considered one o- the ma7or diseases in deveoped countries. eope /ho su--er

-rom hypertension -or on0 periods o- time, /ithout ein0 treated, /i deveop many compications,

incudin0 scerotic processes in the arteries, cardiac insu--iciency, 6idney insu--iciency, stro6es and

dama0e to the retina. Vntreated hypertension reduces i-e e8pectancy y 1+ to 2+ years.

Hne o- the proems in identi-ication o- the disease is that, in most cases, the condition is

nonsymptomatic and most o-ten a dia0nosis is ony made durin0 routine ood pressure tests.


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2. An0iotensin 44 stimuates the adrena corte8 to dischar0e adosterone W dischar0e o- sodium in the

6idneyX W preservation o- -uids in the 6idney W e8traceuar voume↑ W pasma voume↑ W

preoad↑ W ?H↑ W mean↑.

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Endocrinous hypertension

rimary adosteronism $ uncontroed, e8cessive dischar0e o- adosterone -rom a tumor o- the adrena

corte8.


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#ppendix *

Basics of E5. "electrocardioraphy' interpretation

he theoretica ac60round o- heart activity recordin0 /i e discussed ater, /ithin the scope o- the

course on physioo0y o- the ody systems. he purpose o- this appendi8 is to -amiiarie the student /ith

"? recordin0s made in this aoratory.

Electrocardioraphy is a procedure -or recordin0 on paper the eectrica activity o- the myocardium.

Li6e any eectricay$char0ed ody, the myocardium has an eectric -ied. Athou0h the heart is Jhiddendeep in the thora8, its -ied Je8pands and can e identi-ied and samped -rom a distance. "? measures

and records the myocardium9s eectric -ied as pro7ected on the ody9s s6in sur-ace.

he myocardium ces have a rest potentia o- $'+$($*+) mG. he activity potentia o- the myocardium

reaches a pea6 o- T&+$(T+) mG. At any 0iven moment o- the heart activity cyce, part o- the myocardium

is contracted /hie the remainin0 part is rea8ed1. he contracted ces are positivey char0ed reative to

the rea8ed ces and, conse3uenty, the myocardium can e represented as an eectric dipoe havin0 a

0iven eectric -ied.

he eectric -ied o- the dipoe not ony has an asoute vaue, ut aso a direction, and it can e

represented y a vector. Since "? ony constitutes a scaar (numerica) measurement and recordin0 o-

the dipoe eectric -ied that represents the myocardium, sampin0 and measurement o- the -ied isre3uired at a numer o- points, in order to otain a vector o- the dipoe eectric -ied.

4t is a0reed that the eectric -ied o- the heart is measured in the center o- a trian0e, the vertices o- /hich

are the ri0ht shouder, the e-t shouder and the puic symphysis. he trian0e vertices can e moved to

the e-t arm, the ri0ht arm and the e-t e0, accordin0y.

By sampin0 the dipoe eectric -ied /ith the "? apparatus at the trian0e vertices, the direction o-

e8pansion o- depoariation (contraction) and repoariation (rea8ation) in the myocardium can e

estaished. he "? apparatus is a standard votmeter. he si0na measured y the votmeter is

ampi-ied y means o- ampi-iers -or the purpose o- recordin0.

1Since the duration o- the t/itch o- the myocardium ces is simiar to that o- the action potentia, the ce is in a

state o- depoariation at ma8imum contraction.

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4t is a0reed that the eectric si0na, /hich is positive /ith respect to a re-erence point2, is recorded as a

positive deviation -rom the aseine&. "very deviation (aso caed a J/ave), /hether positive or

ne0ative, is mar6ed /ith a etter, e0innin0 /ith the etter .

24n eectrocardio0raphy, t/o 6inds o- re-erence points are used5 they /i e e8pained in the

reevant ectures.

3he "? aseine is caed Jthe isoeectric point. he isoeectric point is potted on paper

/hen there is no potentia di--erence et/een the positive and ne0ative poes o- the terminas o-

the "? apparatus.

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he -irst "? /ave, /ave , indicates depoariation e8pansion in the heart atria, /hich is parae to contraction o-

the atria.

he , R and S /aves indicate e8pansion o- the depoariation (parae to contraction) in the ventrices.

he compe8 o- /aves , R and S, aso caed the JRS compe8, is the most conspicuous "?

compe8 ecause the muscuar mass o- the ventrices is very ar0e, reative to the atria.

he interva et/een the start o- the /ave and the start o- the RS compe8 is the time period re3uired

-or passa0e o- the eectric si0na -rom the sinoatria node (SAN) to the atrioventricuar node (AGN). he

SAN is ocated in the upper part o- the ri0ht atrium, and the AGN is ocated in the o/er part o- the ri0ht

atrium (to e e8act, at the partition et/een the atria and the ventrices).

"? permits characteriation o- not ony the e8pansion o- depoariation in the myocardium, ut aso the

repoariation. Repoariation o- the atria is usuay hidden in the RS compe8 and, conse3uenty,

cannot e identi-ied. Repoariation o- the ventrices creates a /ave. he repoariation process is so/,

as compared /ith depoariation and, there-ore, the /ave ampitude is smaer than the ampitude o- the

RS compe8.

Additiona iterature re-erences re0ardin0 "?

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1. oder0er A.L. in $arrisons principles of internal medicine; "auci #;S;: Braunwald E;: Isselbacher C;D;

"editors''; et a. pp. 12&1$12&%, 1th ed. Mcra/$


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#ppendix <

5ardiac cycle

he attached 0raph descries the time reationships

et/een the various events that ma6e up the cardiac cyce.

Note the division into sta0es,

as sho/n at the top o- the iustration.

Source

Berne R.M., Levy, M.N., Jhysioo0y5

:ourth edition

Documents

Cardiovascular Lab Protocol 2013 (1)