资料来源： 梅根 Fashjian，公元前癌变-贝斯以色列女执事医疗中心，波士顿马萨诸塞州
长期血压 (BP) 描述由血液对血管壁产生的侧压力。BP 是在医院和门诊的设置，经常获得生命体征和最常见的医疗评估之一在世界各地执行。它可以确定与动脉导管直接或间接的方法，是一种非侵入性的安全，方便地重现性好，和因而最常用的技术。BP 测量最重要的应用之一是筛查，诊断，和监测高血压，条件，影响几乎有三分之一的美国成年人，是领先的之一导致心血管疾病。
由振荡或手动听诊利用的血压计袖套崩溃动脉和压力表的压力测量装置，能自动测量 BP。触诊抹杀脉冲压力的测定是在听诊给目标收缩压粗略估计之前完成的。下一步，考官地把听诊器放患者的肱动脉，气囊以上预期的收缩压，然后 auscultates 同时紧缩袖口和观察压力表读数。当袖带中的压力低于肱动脉压力时，部分压缩的动脉的湍流血液流动产生柯氏声音.第一次发声的柯氏声表示收缩期最大的动脉压力。当袖带中的压力进一步减少，并且 （在舒张） 低于最小的动脉压力时，柯氏音变得不再发声。在这点读标志舒张血压.血压是测量在毫米汞柱和记录作为一小部分 (收缩压 / 舒张 BP)。
在大多数情况下，生命体征最初测定保健助理或注册护士 (RN)。医生可以选择重复的生命体征和血压测量病人面试完成后。重复的测量尤其是血压的鉴于潜在的测量误差和血压变化。
An accurate measurement of BP is essential for timely diagnosis and treatment of the underlying condition. Although patients can sustain higher blood pressure (hypertension) for a longer period of time, which is a key factor in developing cardiovascular disease or stroke, a drastically low (hypotensive) or decreasing blood pressure can be fatal if not treated in time. Despite being a simple and non-invasive measurement, obtaining accurate BP is a skill that requires practice, and correct interpretation of the findings requires good understanding of physiology and pathophysiology behind the principle of this procedure.
Blood pressure is a vital sign obtained routinely in hospital and outpatient settings. The term blood pressure describes the lateral pressure produced by blood upon vessel walls. One of the most important applications of blood pressure measurement is the checking for increased blood pressure-a condition termed hypertension. One in every three adults in the United States suffers from hypertension and it is one of the leading causes of cardiovascular diseases.
This video will illustrate the principles behind traditional blood pressure measurement technique and then it will review the critical steps to be followed during this procedure.
The equipment needed for traditional, indirect measurement of blood pressure includes a stethoscope and a sphygmomanometer. The sphygmomanometer consists of a blood pressure cuff containing a distensible bladder, a rubber bulb with an adjustable valve, which when closed helps in cuff inflation and when open releases the built pressure. It also consists of tubing – connecting the cuff to the bulb, and to the manometer, which displays the cuff’s pressure in mmHg.
In order to record the blood pressure reading, the examiner wraps the cuffs around the brachial artery, places a stethoscope over this artery, inflates the cuff above the expected systolic pressure and then deflates it while auscultating and observing the manometer simultaneously.
Initially, when the cuff is fully inflated the artery is squeezed and the blood flow is halted. Thus, there is no sound upon auscultation. Upon deflation, the first appearance of the Korotkoff sounds signifies the systolic pressure, which is audible due to the turbulent blood flow in the partially squeezed artery. Further deflation causes a continual decrease in cuff pressure, and the Korotkoff sounds remain audible throughout, up until the point when the cuff pressure is below the minimal arterial pressure. This reading denotes the diastolic pressure. The fraction of systolic over diastolic is recorded as the final blood pressure reading.
With this knowledge, now let’s go through the step-wise procedure of obtaining accurate blood pressure readings. If necessary, provide the patient with a gown and ensure that he or she is rested for at least 5 minutes prior to obtaining the measurement. To guarantee an accurate reading, ensure that the patient is sitting comfortably with their feet uncrossed and resting on the floor. The cuff should be placed about 2.5 cm above the antecubital fossa. Confirm proper sizing by looking at the index line on the cuff when wrapped around the arm, it should fall within the marked arm circumference range limits. This is critical, as a smaller cuff may falsely elevate the readings and potentially lead to misdiagnosis. Also, make sure that the patient’s arm is resting with the brachial artery at the level of the heart. This is also important, because if the arm is below the heart level it may lead to an overestimation, and if it is above it might result in underestimation of systolic and diastolic pressures.
Next, find the radial pulse with your index finger. Once the pulse is identified, close the valve on the pressure bulb by turning it clockwise. Then, inflate the cuff by squeezing the pressure bulb rapidly. Continue doing this until the radial pulse cannot be felt anymore, and note the mercury level on the manometer. Inflate further until the pressure increases for an additional 30 mmHg. Try not to go beyond this mark as it might lead to unnecessary over inflation, which is uncomfortable for a patient. Then, open the valve slowly by rotating it counterclockwise and deflate the cuff at the rate of approximately 2 mmHg per second until the radial pulse returns. Note the manometer reading when the radial pulse reappears and record it on the vital signs flow sheet as the pulse-obliterating pressure.
After this, proceed to obtaining blood pressure with auscultation. Place the chest piece over the brachial artery in the medial aspect of antecubital fossa. Inflate the cuff again to a level above the pulse-obliterating pressure and confirm that no sound is present. Now, slowly deflate the cuff at a rate of 2 mmHg per second. Listen carefully and note the value on the manometer when the Korotkoff sound can be heard. The manometer reading at that moment corresponds to the systolic blood pressure. Continue slowly deflating the cuff while listening for the sounds to completely disappear. This signifies the diastolic blood pressure. Make sure to deflate the cuff entirely. Record the systolic and diastolic measurements on the vital signs flow sheet.
Normally, the systolic blood pressure on inspiration tends to be lower than the one during expiration due to decreased intrathoracic pressure. However, an abnormally large fall-more than 10 mmHg-in systolic blood pressure on inspiration is defined as pulsus paradoxus, which is most commonly associated with cardiac tamponade or severe chronic obstructive pulmonary disease. To check for pulsus paradoxus, first inflate the cuff to approximately 30 mmHg higher than the previously determined systolic pressure. Deflate at the rate of about 2 mmHg per second. If pulsus paradoxus is present, the first Korotkoff sound is intermittent and occurs just during expiration. Note the reading, which corresponds to higher systolic blood pressure on expiration. Continue to deflate at the same rate until the Korotkoff sounds are audible on both expiration and inspiration-that is with every heartbeat. Note this reading as well, which corresponds to lower systolic blood pressure on inspiration. Calculate the difference between systolic blood pressure on expiration and inspiration to determine if pulsus paradoxus is present or absent.
Lastly, check for orthostatic hypotension. Place the patient in a supine position and wait for a minimum of 5 minutes before obtaining the reading. Obtain a blood pressure measurement in this position following the method described previously. Record the measurement on the vital signs sheet and make sure to note the position of the patient. Next, request the patient to stand and repeat the blood pressure measurement after 3 minutes of standing. Calculate the difference in pressures. If there is a decrease of 20 mmHg or greater in the systolic pressure or 10 mmHg or greater in the diastolic pressure, then the patient suffers from orthostatic hypotension.
You’ve just watched JoVE’s video on how to accurately measure blood pressure. Despite being a simple and non-invasive measurement, obtaining an accurate blood pressure reading is a skill that requires practice. In addition, correct interpretation of the findings requires good understanding of the physiology and the principles behind this procedure. As always, thanks for watching!
