SPHYGMOMANOMETRY.pptx

A detail introduction about sphygmomanometry along with this advancement.

1. SPHYGMOMANOMETRY REETA KARKI

2. INTRODUCTION Sphygmomanometry is the determination of blood pressure through the use of a sphygmomanometer. Sphygmos , pulse, + manos , rare, thin, + metron , measure

3. HISTORY The discovery of blood pressure has been attributed to the Englishman Stephen Hales in 1773. In 1856, Faivre made the first accurate direct assessment of a human patient’s BP by connecting an artery to a mercury manometer during surgery. The forefather of modern sphygmomanometry was Riva Rocci . In 1905, the Russian physician N.C Karotkoff first reported the auscultatory method of indirectly measuring BP.

4. CLINICAL SIGNIFICANCE The prevalence rate of hypertension in the black population is considerably higher than in the white population. Black develops hypertension at the earlier age and it is likely to be more severe than in other racial groups. The systolic pressure is the pressure in the arteries, at the height of pulsation, caused by cardiac contraction as the left ventricle pumps blood into the aorta. The diastolic pressure is the pressure in the arteries during ventricular relaxation between cardiac contraction.

5. Indirect vs Direct Blood Pressure Measurement Direct blood pressure is measured through the use of catheter inserted into a major artery that is usually connected to the electronic-recording system. Indirect blood pressure can be measured by using stethoscope and sphygmomanometer.

6. The Karotkoff Sounds Karotkoff described the sound produced from the time the artery was completely compressed until initial refilling occur. The first and last phases of these sounds, corresponding to the fist audible detection to their disappearance, determine the systolic and diastolic readings respectively which is expressed in mm of Hg.

7. The Karotkoff sounds PHASE I Sudden appearance of clear, regular tapping sounds PHASE II A swishing softening of sounds. PHASE III Crisper sounds, increasing in intensity PHASE IV Abrupt damping or muffling of sounds PHASE V Complete disappearance of sound

8. INSTRUMENTATION THEORY the circulatory mechanism is a closed system comprised of the cardiac pump that forces a finite supply of blood through a complex arterial tree. the systemic arterial bp represent the force applied against blood vessel walls resulting from the direct effects of cardiac output(CO) and peripheral vascular resistance(R).

9. Effects of cardiac output and Peripheral vascular resistance Cause Clinical example Effect Increase CO Heavy exertion such as exercise Increased BP Decrease CO Myocardial infarction Decreased BP Increased R Peripheral vasocontriction from sympathomimetics such as phenylepinephrine Increased BP Decreased R Peripheral vasodilation from sublingual nitroglycerin use Decreased BP

10. Other factors contributing to arterial blood pressure levels Cause Clinical example Effect Blood volume If reduced by major blood loss from trauma or surgery Decreased BP Blood viscosity If elevated as measured by hematocrit in polycythemia Increased BP Arterial wall elasticity If reduced because of atherosclerosis Increased BP

11. STETHOSCOPE The stethoscope is used to determine the systolic and diastolic readings through auscultation of the Karotkoff sounds. It comprises of earpieces, binaurals , plastic or rubber tubing, and a chest piece.

12. The rubber or plastic coated earpieces should fit comfortably but snugly to block out external noises. The binaurals are angled to follow the contour of the auditory canal. A spring clamp connecting the binaurals is often present to help maintain tight contact with auditory openings. The chest piece has two components, a bell and a diaphragm. The diaphragm is the circular, flat-surfaced portion ending in a thin plastic disk that transmit high frequency sounds. The bell side of the chest piece transmits low-frequency sounds. Depending upon the need of examiner, either the bell or diaphragm portion is rotated or clicked into position so that sounds tranmit .

13. SPHYGMOMANOMETER The blood pressure cuff, or sphygmomanometer is comprised of a non-stretchable fabric bag joining at the ends by Vecro cloth strips & contains an inflatable rubber bladder. Connected to the cuff by one or more rubber tubes are an inflating bulb, with a pressure release valve, and a manometer gauge.

14. In the clinical setting, the cuff pressure is registered by either a mercury or an aneroid manometer. The mercury manometer consists a narrow vertical column of Hg within a glassor plastic tube that is set upright on a table top. Mercury manometer is the standard and accuracy is ensured when the meniscus level reads zero when no pressure is applied and when the column is observed to fall freely as the cuff pressure is released. The aneroid manometer consist a small metal bellows or spring that moves a needle across a caliberated dial to register change in pressure.

15. The length of the arterial segment that is compressed by the inflated cuff during BP measurement is one of the important factos influencing the accuracy of the reading. Usually it has been determined that sphygmomanometry in the average sized adult is most accurate when performed with a cuff 12 to 14 cm wide. The cuff sizes mostly used in optometry practices are child, adult, and thing for taking the BP of leg.

16. CATEGORIES OF AVAILABLE SPHYGMOMANOMETERS Mercury Manometer Aneroid Manometer Electronic Stationary automated Automatic ambulatory

17. MERCURY MANOMETER

18. ANEROID MANOMETER

19. ELECTRONIC MANOMETER

20. DIFFERENT CUFF SIZES

21. CLINICAL PROCEDURE video

22. CLINICAL IMPLICATIONS DIURNAL VARIATION With use of an intra-arterial device continuously over a 24 hr period in 20 untreated ambulatory hypertensives , Millar Craig et al. reported that highest BP values in the mid-morning, a progressive fall throughout the day, and lowest readings during sleep.

23. INTRAOBSERVER VARIABILITY For variety of reasons, including errors in technique, inadequate training, carelessness, digital preferencing , and preconceived expectations, blood pressure readings have been found to vary widely between different observers. Mitchell and Van Meter, in comparing sphygmomanometry readings obtained by nursing personnel and the investigators, found differences of more than 15 mm Hg in 21% to 27% of the readings.

24. DIASTOLIC END POINT Some conterversy persists over the correct and more accurate diastolic reading, either phase IV Korotkoff (Diastolic I), when the muffling sound first occurs, or the complete disappearance of sound of Phase V Korotkoff (Diastolic II). The American Heart Association recommends the Phase V be used as the diastolic readings for adults except for those with hyperkinetic condition, such as hyperthyroidism. For hyperkinetic adult and for children Phase IV is recommended as the diastolic end point.

25. DIFFERENCE IN RIGHT AND LEFT ARM READINGS During initial visit, the bp of both arms should be measured. If the difference in the readings is noted, the arm with higher reading is used for future measurement. A 5-10 mm Hg difference between two arm reading is within normal limits. Differences in the readings greater than 10-15 mm Hg could be indicative of atherosclerotic narrowing of the subclavian or brachiocephalic arteries as a part of subclavian steal syndrome.

26. WEAK OR INAUDIBLE KOROTKOFF SOUNDS Elevating the patient’s arm before inflating the cuff will empty the blood from foramen and will increase the gradient inflow between portions of artery proximal and distal to the cuff. Finally, inflating the cuff quickly will minimize the amount of blood trapped in the forearm due to venous congestion that decreases the flow gradient of arterial blood passing under the cuff during dflation and may reduce audibility of the Korotkoff sounds.

27. ORTHOSTATIC(POSTURAL) HYPOTENSION An adult whose bp is 95/60 or less, without a postural change, is considered to be hypotensive. As a patient changes from a lying or sitting position to a standing position, the systolic pressure drops slightly or remains unchanged, whereas the diastolic pressure rises slightly. Orthostatic hypertension will be apparent by the changes in bp measured in the supine, sitting, and standing position.

28. FALSELY LOW READINGS FALSELY LOW READINGS Cuff too wide Deflating the cuff too rapidly(systolic) Patient’s arm above heart level Auscultatory gap

29. FALSELY HIGH READINGS FALSELY HIGH READINGS Patient anxiety, fear, emotional stress Cuff too narrow or too loose Deflating the cuff too slowly Deflating the cuff too rapidly Patient’s arm below heart level Pseudohypertension

30. REFERENCES CLINICAL PROCEDURES IN OPTOMETRY INTERNET