Pulse tripleresponse
- 2. Arterial pulse A pulse represents the tactile arterial palpation of the heartbeat The pulse may be palpated in any place that allows an artery to be compressed against a bone such as; at the neck (carotid artery), on the inside of the elbow (brachial artery), at the wrist (radial artery), at the groin (femoral artery near the ankle joint (posterior tibial artery), and on foot (dorsalis pedis artery) Pulse (or the count of arterial pulse per minute) is equivalent to measuring the heart rate The heart rate can also be measured by listening to the heart beat directly (auscultation), traditionally using a stethoscope and counting it for a minute
- 3. Measuring pulse • The radial pulse is commonly measured using three fingers • The study of the pulse is known as sphygmology
- 4. Pulse • Pressure waves generated by the heart in systole move the arterial walls • Forward movement of blood occurs and is enough to create a palpable pressure wave • The heart rate may be greater or lesser than the pulse rate depending upon physiologic demand • In this case, the heart rate is determined by auscultation or audible sounds at the heart apex, in which case it is not the pulse • The pulse deficit (difference between heart beats and pulsations at the periphery) is determined by simultaneous palpation at the radial artery and auscultation at the heart apex • It may be present in case of premature beats or atrial fibrillation • Pulse velocity, pulse deficits and much more physiologic data are readily and simplistically visualized by the use of one or more arterial catheters connected to a transducer and oscilloscope • This invasive technique has been commonly used in intensive care since the 1970s
- 5. Normal pulse rate • Newborn (0–3 months old) - 100-150 • Infants (3 – 6 months) -90–120 • Infants (6 – 12 months) -80-120 • Children (1 – 10 years) -70–130 • children over 10 years & adults including seniors -60–100 • well-trained adult athletes -40–60
- 6. Pulse • Volume: The degree of expansion displayed by artery during diastolic and systolic state is called volume. It is also known as amplitude, expansion or size of pulse • Hypokinetic pulse: A weak pulse signifies narrow pulse pressure • It may be due to low cardiac output (as seen in shock, congestive cardiac failure), hypovolemia, valvular heart disease (such as aortic outflow tract obstruction, mitral stenosis, aortic arch syndrome) etc. • Hyperkinetic pulse: A bounding pulse signifies high pulse pressure. It may be due to low peripheral resistance – (as seen in fever, anemia, thyrotoxicosis, hyperkinetic heart syndrome (de), A-V fistula, Paget's disease, beriberi, liver cirrhosis), increased cardiac output, increased stroke volume (as seen in anxiety, exercise, complete heart block, aortic regurgitation), decreased distensibility of arterial system (as seen in atherosclerosis, hypertension etc. • The strength of the pulse can also be reported: – 0 = Absent – 1 = Barely palpable – 2 = Easily palpable – 3 = Full – 4 = Aneurysmal or bounding pulse
- 7. Venous pressure • The evaluation of the venous pulse is an integral part of the physical examination as it – reflects both the mean right atrial pressure and – the hemodynamic events in the right atrium • Factors influencing the right atrial and central venous pressure (CVP) includes – total blood volume – the distribution of blood volume, and – right atrial contraction • Venous blood returning from the systemic capillaries is nonpulsatile • Changes in flow and pressure caused by skeletal muscles and respiratory pump are non-synchronous with the pulsatile activity of the heart
- 8. Venous pressure • Changes in flow and pressure caused by right atrial and ventricular filling • Produce pulsations in the central veins that are transmitted toward the peripheral veins, opposite to the direction of blood flow • With the possible exception of the "c" wave, which is the combined result of carotid arterial impact and upward movement of the tricuspid valve • the pulsations observed in the neck are produced by right atria and ventricular activity
- 9. Venous pulse • Normal venous pulse (JVP) reflects phasic pressure changes in the right atrium and consists of three positive waves and two negative troughs • In considering this pulse it is useful to refer to the events of the cardiac cycle • The positive presystolic "a" wave is produced by right atrial contraction and is the dominant wave in the JVP particularly during inspiration
- 10. Venous pulse • During atrial relaxation, the venous pulse descends from the summit of the "a" wave depending on the PR interval, this descent may continue until a plateau ("z" point) is reached just prior to right ventricular systole • More often the descent is interrupted by a second positive venous wave, "c" wave, which is produced by a bulging of the tricuspid valve into the right atrium during right ventricular isovolumic systole and by the impact of the crowded artery adjacent to the jugular vein • Following the summit of the "c" wave, the JV P contour declines, forming the normal negative systolic wave, the "x" wave • The "x" descent is due to a combination of atrial relaxation, the downward displacement of the tricuspid valve during right ventricular systole, and the ejection of blood from both the ventricles
- 11. V wave in JVP • The positive, late systolic "v" wave in the JVP results from the increase in blood volume in the venae cavae and the right atrium during ventricular systole when the tricuspid valve is closed • After the peak of the "v" wave is reached, the right atrial pressure decreases because of the diminished bulging of the tricuspid valve into the right atrium and the decline in right ventricular pressure which follow tricuspid valve opening The latter occurs at the peak of the "v" wave in the JVP
- 12. Y wave • Following the summit of the "v" wave, there is a negative descending limb, referred to as the "y" descent or diastolic collapse • due to the tricuspid valve opening in the rapid and • flow of blood into the right ventricle • The initial "y" descent corresponds to the right ventricular rapid filling phase • The trough of the "y" wave occurs in early diastole and is followed by the ascending limb of the "y"wave, which is produced by continued diastolic inflow of blood into the right side of the heart • The velocity of this ascending pressure curve depends on the rate of venous return and the distensibility of the chambers of the right side of the heart • When diastole is long, the descending limb of the "y" wave is often followed by a small, brief, positive wave, the "h" wave, which occurs just prior to the next "a" wave.
- 13. JVP • At times, there is a plateau phase rather than a distinct "h" wave • With increasing pulse rate the "y" trough and the "y" ascent are followed immediately by the next "a "wave • Usually -three visible major positive waves ("a", "c", "v") and two negative wave ("x", "y") when the pulse rate is below 90 beats per minute and the PR interval is normal • With faster heart rates there is often fusion of the some of the pulse waves and an accurate analysis of the waveform is more difficult
- 14. Circulation Time • "Average time taken for a RBC (or injected dye*) to traverse the systemic & pulmonary circulations, and return to the starting point". • For example: • Coronary route =10 sec • Some routes = several minutes (extensive venous sinuses spleen, etc.) • Body average = 40 -60 sec. (vol. of the cardiac output circulated approximately once per min) • Affected by: • Circulation time is decreased by exercise, arteriovenous shunting, reduced venous pooling • Most of time is spent in the veins; thus, circulation time is more dependent on what happens in the veins than in the arteries, arterioles (i.e. vaso - venomotion)
- 15. Circulation time • Measurement of the circulation time through the heart and lungs is one of the most widely used tests of circulatory efficiency in clinical medicine • As Wiggers pointed out, circulation time is not the time required for the blood to make a complete circulation, because – any given corpuscle has such a wide variety of paths over which to travel as to make such a concept meaningless • With many authors the term "circulation time" seems to imply a measure of the mean velocity of flow of an injected substance from the point of injection to the place of detection • According to Blumgart -"the interval of time necessary for the fastest particle of a foreign substance to traverse the shortest available path between the point of injection and the place of detection • it is almost universally recognized that as a clinical test the circulation time is useful in both establishing diagnoses and following the course of disease • It becomes prolonged in congestive heart failure and returns toward normal with relief of failure • it is usually normal or rapid in heart failure due to anemia, thyrotoxicosis, beriberi and arteriovenous fistula
- 16. Factors affecting circulation time • Blumgart demonstrated that the circulation time is affected by the cross-sectional area of the pathway traveled, which in turn is a function of the amount of blood in the pulmonary Circulation, vascular bed and the condition of its vessels • widening of the pathway will allow the same volume per unit time to pass at a diminished speed • narrowing of the vascular caliber significantly impedes flow, slowing will occur • Increasing minute output increases the rate of flow (and decreases circulation time) if other factors remain the same • Decreased cardiac output has the opposite effect • Thus in myxoedema without heart failure the circulation time is prolonged in association with a diminished cardiac output • Conversely, circulation time is notoriously rapid in Grave's disease, even with heart failure and dilatation of the vascular bed, both of which would tend to prolong it • This must be due to the marked increase in cardiac output which commonly occurs in hyperthyroidism
- 17. Circulation time • laminar flow must be minimal in a system with pulsations, changing frictions, changing diameters, turns and branchings • The viscosity of the blood will be reflected in the cardiac output, dilution and cross-sectional parameters • For example, in anemia the cardiac output increases and the blood volume decreases with a resulting rapid circulation time • Conversely, in polycythemia the cardiac output is normal, more RBC- more viscous and so the circulation time may be prolonged • Therefore, it would seem that the circulation time, as here defined, is a function of; – the cross-sectional area of the pulmonary vascular bed (controlled by the volume of blood in the lungs) – the cardiac output (itself affected by factors such as peripheral resistance), and – the amount of dilution of the injected mass by the blood in the heart and lungs – An additional factor -the time of injection to the phase of the cardiac and respiratory cycles
- 18. Triple response of Lewis • Evolution of inflammatory processes in the three points described by Lewis. • The triple response of Lewis is a cutaneous inflammatory response that occurs from firm stroking of the skin, which produces an initial red line, followed by a flare around that line, and then finally a wheal • The triple response of Lewis is due to the release of histamine • Histamine, or 2-(imidazol-4-yl)ethanamine, is a dibasic vasoactive amine that is located in most body tissues but is highly concentrated in the lungs, skin, and gastrointestinal tract • Histamine is derived from the decarboxylation of the aminoacid histidine, a reaction catalyzed by the enzyme L-histidine decarboxylase • Histamine is a small molecule, stored in granules of mast cells and basophils
- 19. Triple response • 3 part response that consists of: 1) red reaction • - occurs due to the relaxation of the pre-capillary sphincters leading to an increase in blood flow - relaxation of the pre-capillary sphincters is mediated by histamine, which is released from mast cells (not nerves) * the red reaction occurs within 30s 2) wheal • The wheal refers to the swelling / local odema. It is due to: 1) histamine acting on the endothelial cells of the capillaries increasing their permeability. 2) increase in capillary hydrostatic pressure caused by histamine's dilator effects at the arteriole end and its constrictor effect at the venule end (so that fluid is not resorbed back into the capillary) • More fluid is leaving the capillary and less is being resorbed.
- 20. Flare • Refers to the irregularly outlined area of red skin spreading beyond the red line - The flare is due to an axon reflex - skin receptors in the epidermis are stimulated by the release of histamine from mast cells • The stimuli from the skin receptor travel up the sensory neurone and relayed anti-dromically to the sensory neuron from the arteriole • The stimuli from the skin travel down the sensory neurone from the arteriole and causes arteriolar dilation by releasing substance P • Substance P acts on arterioles and causes vasodilation, increasing blood flow to the arterioles • anti-dromic conduction: when impulses travel in the opposite direction • orthodromic conduction: when impulse conduction is in the usual direction.