Arterial Blood Pressure Arterial Blood Pressure. Definition. Factor affecting blood pressure. Causes. Classification. Type of blood pressure apparatuses.
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Arterial Blood Arterial Blood PressurePressure
Definition.Definition.Factor affecting blood Factor affecting blood pressure .pressure .Causes .Causes .Classification .Classification .Type of blood pressure Type of blood pressure apparatuses .apparatuses .How to measure .How to measure .Treatment .Treatment .
Arterial Blood Pressure Arterial Blood Pressure (BP)(BP)
Is a measure of the force that the circulating blood exerts against the arterial wall
OR
The pressure force generated by the pumping action of the heart on the wall of aorta & arterial blood vessels per unit area.
It tells us how hard the heart is working.
Too high means the heart is working extra hard and this could be very dangerous!
Blood pressure almost always is measured in millimeters of mercury (mmHg).
Occasionally pressure is measured in centimeters of water ( cm H2O)
1 mmHg = 1.36 cm H2O
Factors affecting BPFactors affecting BP Sex M > F …due to hormones/ equal at
menopause. Age Elderly > children …due to atherosclerosis. Emotions due to secretion of adrenaline &
noradrenaline. Exercise due to venous return. Hormones … (e.g. Adrenaline, noradrenaline,
thyroid H). Gravity Lower limbs > upper limbs. Race Orientals > Westerns … ? dietry factors,
or weather. Sleep due to venous return.
(BP)
Factors determining BPFactors determining BP
(CO)Flow
Blood Pressure = Cardiac Output X Peripheral Resistance
(PR)Diameter
of arterioles
BP depends on:
1. Cardiac output. 2. Peripheral resistance. 3. Blood volume.
Cardiac Output Cardiac Output Is the volume of blood being pumped by the heart, in particular by a Left or Right ventricle in the Time interval of one minuteCardiac Output (Q) = SV × HR
Peripheral ResistancePeripheral ResistanceThe sum of resistance to flow that must be overcome to push blood through the circulatory system
Stroke VolumeStroke VolumeIs the volume of blood pumped from one ventricle of the heart with each beat
Causes Of HypertensionCauses Of HypertensionEssential hypertension 95%Secondary hypertension 5%
RenalEndocrinePregnancyDrugsCoartation of aortaOthers
Blood PressureBlood Pressure
Pulse pressure Systolic BP – Diastolic BP
The most important determinant of pulse pressure is STROKE VOLUME.
Mean arterial pressure Diastolic BP + 1/3 Pulse pressure
Is a term used in medicine to describe an average blood pressure in an individual
NOTENOTE !!! !!!
HypertensionHypertension
Sustained raised in BP which require medical interventions.
Classification of blood pressure for adults
Category Systolic mmHg Diastolic mmHg
Hypotension < 90 < 60
Normal 90 – 120 60 – 80
Prehypertension 121 – 139 81 – 89
Stage 1 Hypertension 140 – 159 90 – 99
Stage 2 Hypertension ≥ 160 ≥ 100
How is Blood Pressure How is Blood Pressure Taken?Taken?
Invasi
ve
Non-I
nvasi
ve
Blood Pressure
Palpatory Method
Auscultatory Method
Ultrasonic MethodOscillometric Method
Tonometry
Extravascular Sensor
Intravascular Sensor
Types Of BP ApparatusesTypes Of BP ApparatusesMercury Type Aneroid Type
Digital Type
A- Palpatory MethodA- Palpatory MethodFeel the radial pulse.An occlusive cuff is placed on arm and
inflated above the level at which the pulse become impalpable.
Gradually deflate it.The level at which the pulse become
palpable again is taken as systolic pressure.
1- The blood pressure can be measured in noisy environment too
ADVANTAGES
2- Technique does not require much equipment
1- Only the systolic pressure can be measured (not DP)
DISADVANTAGES
2- The technique does not give accurate results for infants and hypotensive patients
B- B- Auscultatory MethodAuscultatory MethodApply the cuff one inch above the elbowPalpate the brachial arteryPlace the stethoscope lightly over itInflate the cuff above the systolic level
determined by the palpatory methodLower the pressure in the cuff The level at which Korotkoff sound are
heard is the Systolic pressure.The level at which sound disappear is
diastolic pressure.
1- Auscultatory technique is simple and does not require much equipment
ADVANTAGES
DISADVANTAGES1- Auscultatory tecnique cannot be used in noisy
environment2- The observations differ from observer to
another3- A mechanical error might be introduced into the
system e.g. mercury leakage, air leakage, obstruction in the cuff etc.
4- The technique does not give accurate results for infants and hypotensive patients
1. The first Korotkoff sound is Clear tapping, repetitive sounds for at least two consecutive beats is considered the systolic pressure.
2. The second sounds are the murmurs heard for most of the area between the systolic and diastolic pressures.
3. The third = A loud, crisp tapping sound.4. The fourth sound, at pressures within 10
mmHg above the diastolic blood pressure, were described as “muffling" and "muting".
5. The fifth Korotkoff sound is silence as the cuff pressure drops below the diastolic blood pressure. The disappearance of sound is considered diastolic blood pressure .
Korotkoff soundKorotkoff sound
Common problem in BP Common problem in BP measurementmeasurementWrong cuff sizeExcess pressure of stethoscopePatient arm at the wrong levelWhite coat effectAuscultatory Gap (silent gap)
Auscultatory GapAuscultatory GapIn some hypertensive patients the
Krotokoff sound disappear for some time between systolic and diastolic pressure.
So there is a risk of either recording a low systolic or high diastolic .
Avoid it by using palpatory method before the Auscultatory method.
Treatment Treatment Treatment goal <140/85 mmHg
(130/80 mmHg in diabetic)
Lifestyle changes include :Stop smokingLow fat dietLow salt intakeExerciseReduce wt
Drugs:
ACE inhibitorB-blockerCa channel blockerDiurtics
Postural HypotensionPostural HypotensionDrop in systolic BP>20 mmHg OR
diastolic BP>10 mmHg after standing for 3 minutes.
Causes:HypovolemiaAntipsychoticsAddison‘s diseasehypopituitarism
Apply Your KnowledgeApply Your KnowledgeNormal Blood Pressure in Adults (18 or older)
is ??What can cause sounds to be heard down to
zero mmHg??A cuff with a bladder too small for the
patients arm will result in ?? If the cuff is applied too loosely, the pressure
reading will be ?? How you can avoid incorrectly assessing the
systolic blood pressure due to the auscultatory gap??
Thank youThank you
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