Vital SignsVital signs include the measurement of: temperature, respiratory rate, pulse, blood pressure and, where appropriate, blood oxygen saturation. These numbers provide critical information (hence the name "vital") about a patient's state of health. In particular, they: Show
Most patients will have had their vital signs measured by an RN or health care assistant before you have a chance to see them. However, these values are of such great importance that you should get in the habit of repeating them yourself, particularly if you are going to use these values as the basis for management decisions. This not only allows you to practice obtaining vital signs but provides an opportunity to verify their accuracy. As noted below, there is significant potential for measurement error, so repeat determinations can provide critical information. Getting Started: The examination room should be quiet, warm and well lit. After you have finished interviewing the patient, provide them with a gown (a.k.a. "Johnny") and leave the room (or draw a separating curtain) while they change. Instruct them to remove all of their clothing (except for briefs) and put on the gown so that the opening is in the rear. Occasionally, patient's will end up using them as ponchos, capes or in other creative ways. While this may make for a more attractive ensemble it will also, unfortunately, interfere with your ability to perform an examination! Prior to measuring vital signs, the patient should have had the opportunity to sit for approximately five minutes so that the values are not affected by the exertion required to walk to the exam room. All measurements are made while the patient is seated. Observation: Before diving in, take a minute or so to look at the patient in their entirety, making your observations, if possible, from an out-of-the way perch. Does the patient seem anxious, in pain, upset? What about their dress and hygiene? Remember, the exam begins as soon as you lay eyes on the patient. Temperature: This is generally obtained using an oral thermometer that provides a digital reading when the sensor is placed under the patient's tongue. As most exam rooms do not have thermometers, it is not necessary to repeat this measurement unless, of course, the recorded value seems discordant with the patient's clinical condition (e.g. they feel hot but reportedly have no fever or vice versa). Depending on the bias of a particular institution, temperature is measured in either Celcius or Farenheit, with a fever defined as greater than 38-38.5 C or 101-101.5 F. Rectal temperatures, which most closely reflect internal or core values, are approximately 1 degree F higher than those obtained orally. Respiratory Rate: Respirations are recorded as breaths per minute. They should be counted for at least 30 seconds as the total number of breaths in a 15 second period is rather small and any miscounting can result in rather large errors when multiplied by 4. Try to do this as surreptitiously as possible so that the patient does not consciously alter their rate of breathing. This can be done by observing the rise and fall of the patient's hospital gown while you appear to be taking their pulse. Normal is between 12 and 20. In general, this measurement offers no relevant information for the routine examination. However, particularly in the setting of cardio-pulmonary illness, it can be a very reliable marker of disease activity. Pulse: This can be measured at any place where there is a large artery (e.g. carotid, femoral, or simply by listening over the heart), though for the sake of convenience it is generally done by palpating the radial impulse. You may find it helpful to feel both radial arteries simultaneously, doubling the sensory input and helping to insure the accuracy of your measurements. Place the tips of your index and middle fingers just proximal to the patients wrist on the thumb side, orienting them so that they are both over the length of the vessel. Vascular Anatomy Technique for Measuring the Radial Pulse The pictures below demonstrate the location of the radial artery (surface anatomy on the left, gross anatomy on the right). Frequently, you can see transmitted pulsations on careful visual inspection of this region, which may help in locating this artery. Upper extremity peripheral vascular disease is relatively uncommon, so the radial artery should be readily palpable in most patients. Push lightly at first, adding pressure if there is a lot of subcutaneous fat or you are unable to detect a pulse. If you push too hard, you might occlude the vessel and mistake your own pulse for that of the patient. During palpation, note the following:
Rhythm Simulator Blood Pressure: Blood pressure (BP) is typically measured using an anaeroid manometer, with readings reported in millimeters of mercury (mm Hg). While most BP readings in hospitals and clinics are initially taken with digital machines, it's still relevant to learn how to use manual cuffs, as clinicians will need to check the validity of digital readings on occasion (e.g. when BP unexpectedly high or low). The size of the BP cuff will affect the accuracy of these readings. The inflatable bladder, which can be felt through the vinyl covering of the cuff, should reach roughly 80% around the circumference of the arm while its width should cover roughly 40%. If it is too small, the readings will be artificially elevated. The opposite occurs if the cuff is too large. Clinics should have at least 2 cuff sizes available, normal and large. Try to use the one that is most appropriate, recognizing that there will rarely be a perfect fit. Blood Pressure Cuffs In order to measure the BP, proceed as follows:
Implications, interpretation and other clinical pearls related to hypertension: Hypertension is a common disease, affecting > 40% of the adult US population. With the steady increase in obesity rates, it’s anticipated that this % will continue to increase. Normal values and definitions for hypertension are as follows:
The diagnosis of hypertension is typically based on 2 readings, done at 2 different settings. A one-time measurement > 160/100 should prompt consideration for treatment. Home readings (with a validated device) can also be used for the diagnosis and management of hypertension. Careful attention must be paid to the use of appropriate techniques (described above), as measurement error(s) can lead to inaccurate values and diagnoses. Hypertension (HTN) causes and accelerates the progression of: Coronary artery disease, heart failure with reduced ejection fraction (HFrEF), heart failure with preserved ejection fraction (HFpEF), left ventricular hypertrophy, aortic aneurysm development, peripheral arterial disease, stroke, chronic kidney disease, and retinopathy. The risk of HTN induced damage correlates with both the height of BP and the chronicity of elevation (i.e. longer and higher is worse). The treatment of HTN prior to the development of Target Organ Damage (a.k.a. TOD) is referred to as "primary prevention," while treatment to prevent and/or slow progression once disease has already been established is called "secondary prevention." Evaluation of patients with HTN requires careful history taking, physical exam, labs, and other studies to search for co-morbid problems (e.g. diabetes, sleep apnea, etc.) and/or occult TOD. Most patients with HTN are asymptomatic, at least until they develop target organ damage, which can take years to manifest. A few additional clinically oriented thoughts:
Orthostatic (a.k.a. postural) measurements of pulse and blood pressure are often part of the assessment for hypovolemia and/or dizziness. This requires first measuring HR and BP when the patient is supine and then repeating them after the patient has stood for a few minutes. Normally, SBP doesn’t vary by more than ~20 points and DBP by more than ~10 points when a patient moves from lying to standing. In the setting of significant volume depletion, a greater drop may be seen. This may also be associated with symptoms of cerebral hypo-perfusion (e.g. light headedness). In the setting of acute GI bleeding, for example, a drop in blood pressure and/or rise in heart rate when moving from lying to standing is a marker of significant blood loss and has important prognostic implications. It is also possible to have volume loss without attendant postural changes (i.e. the absence of changes doesn’t rule out hypovolemia). Orthostatic measurements may also be used to determine if postural dizziness or syncope/presyncope are the result of a fall in blood pressure. For example, patients who suffer from diabetes may have autonomic nervous system dysfunction and impaired ability to appropriately vasoconstrict when changing positions. If their dizziness/lightheadedness is the result of orthostatic changes, then their BP will drop when they move from a lying to standing position and their symptoms will be reproduced. The 20-point value is a rough guideline. In general, the greater the change in BP, the more likely it is to cause symptoms and be of clinical significance. The following are links to useful additional information about BP measurement and hypertension.
Oxygen Saturation: Over the past decade, this non-invasive measurement of gas exchange and red blood cell oxygen carrying capacity has become available in all hospitals and many clinics. While imperfect, it can provide important information about cardio-pulmonary dysfunction and is considered by many to be a fifth vital sign. In particular, for those suffering from either acute or chronic cardio-pulmonary disorders, it can help quantify the degree of impairment. Pulse Oxymeter How do you check for orthostatic vitals?1 Have the patient lie down for 5 minutes. 2 Measure blood pressure and pulse rate. 3 Have the patient stand. 4 Repeat blood pressure and pulse rate measurements after standing 1 and 3 minutes.
What is the initial step in assessing a patient for orthostatic hypotension?The initial assessment should include BP and heart rate measurement when the patient has been supine for at least 5 minutes and ideally at both 1 and 3 minutes of standing.
When should orthostatic blood pressure be checked?A new study led by Johns Hopkins researchers suggests that testing for the presence of orthostatic hypotension, a form of low blood pressure, be performed within one minute of standing after a person has been lying down. Current guidelines recommend taking the measurement three minutes after a person stands up.
What are orthostatic vital sign changes?Orthostatic vital signs may be indicated to evaluate patients who are at risk for hypovolemia (vomiting, diarrhea, bleeding), have had syncope or near syncope (dizziness, fainting), or are at risk for falls. A significant change in vital signs with a change in position also signals increased risk for falls.
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