Cuff inflation

Cardiovascular activity such as heart rate and variation in blood pressure is typically examined by a sphygmomanometer (with the cuff inflated to 60mmHg). Blood pressure is the force exerted on the outside wails of blood vessels throughout the body as the heart contracts and relaxes. The pressurized cuff of the sphygmomanometer captures cuff-pressure oscillation [7]. A pressure transducer within the polygraph instrument captures and records this change in pressure. 

Tracheostomy tubes are associated with long-term complications, particularly related to cuff inflation (4). As this population has already failed endotracheal weaning, they must be approached in a systematic way to optimize the likelihood of success. Ceriana et al. have suggested a decision tree to help with this process (5). 

During a follow-up study she was noted to have an elevated PCO2 associated with leakage around her tracheostomy tube. This was addressed by increasing her cuff inflation pressure by adding 1 cc of water (Fig. 12). This cuff inflation resulted in improved ventilation, as shown (Fig. 13) by increased respiratory excursions and increased exhaled volumes. 

Figure 13 Representative epochs from a overnight polysomnogram, showing the effect of adequate cuff inflation on ventilation. On the left panel, respiratory excursions, ventilator pressures and exhaled volumes are reduced, associated with leakage around the tracheostomy, compared with the same measures (right panel), repeated after adequate tracheostomy cuff inflation.

To reduce deviations in blood pressure measurement in the clinic, the patient and clinician should not talk during blood pressure readings. The measurement arm is supported and positioned at heart level with the blood pressure cuff encircling at least 80% of arm circumference. If a mercury or aneroid device is used, then the palpatory method must be used first to estimate the systolic blood pressure.18 If an automated device is used, this is not necessary. After the patient s cuff is inflated above the systolic pressure, the mercury column should drop at a rate of 2 to 3 mm per second. A stethoscope placed over the brachial artery in the antecubital fossa identifies the first and last audible Korotkoff sounds, which should be taken as systolic and diastolic pressure, respectively. A minimum of two readings at least 1 minute apart are then averaged. If measurements... 

Crenshaw AG, Hargens AR, Gershuni DH, Rydevik B. Wide tourniquet cuffs more effective at lower inflation pressures. Acta Orthop Scand 1988 59 447-51. 

The beauty of the mercury manometer is that you can assess its accuracy by simply looking at it. If the mercury meniscus is at zero when there is no pressure in the cuff and the column moves smoothly with inflation and deflation it is accurate and can be used as the gold standard for pressure measurement. All other devices must be calibrated against a... 

To test blood pressure, the doctor or another health professional inflates a cuff placed around the arm above the elbow. He or she then listens for specific sounds through a stethoscope placed at the crook of the elbow as the cuff is gradually deflated. The first of those sounds signals the time the heart beats and the fifth and final sound notes the heart at rest between beats. The pressure at the time of those two sounds is noted in a column of mercury similar to that in a thermometer, on a device called a sphygmomanometer, which is frequently mounted on the wall. The first, beating pressure... 

Even though the home monitoring devices are extremely easy to use, technique is important to assure accurate blood pressure measurements. It s best to sit at a table or a desk, wrap the cuff around the arm as directed in the instructions, and relax for a couple of minutes before inflating the cuff. Keep both feet on the floor and try to remain still, since movement can decrease accuracy. Your arm and cuff should be at the same height as your heart. Hit the start button and note your blood pressure. Many machines also measure heart rate. Wait a couple more minutes and repeat the procedure. You ll probably find that the first measurement is higher. 

So try this experiment for yourself. Sit down with the blood pressure monitor in place, the cuff around your upper arm. Push the button, take your blood pressure reading, and make a note of it. Now close your eyes for two to three minutes, and concentrate on breathing in and out, slowly and deeply. Imagine your chest as an inflating and deflating balloon. After that two- to three-minute breathing exercise, take your blood pressure again. You ll be amazed at the improvement. 

Intravenous. A double cuff is applied to the arm, inflated above arterial pressure after elevating the limb to drain the venous system, and the veins filled with local anaesthetic, e.g. 0.5-1% lidocaine without adrenaline (epinephrine). The arm is anaesthetised in 6-8 min, and the effect lasts for up to 40 min if the cuff remains inflated. The cuff must not be deflated for at least 20 minutes. The technique is useful in providing anaesthesia for the treatment of injuries speedily and conveniently, and many patients can leave hospital soon after the procedure. The technique must be meticulously conducted, for if the full dose of local anaesthetic is accidentally suddenly released into the general circulation severe toxicity and even cardiac arrest may result. Bupivacaine is no longer used for intravenous regional anaesthesia as cardiac arrest caused by it is particularly resistant to treatment. Patients should be fasted and someone skilled in resuscitation must be present. 

Spontaneously hypertensive rats can be used to screen compounds for antihypertensive effects and for effects on heart rate. The animals are dosed for one or a few days. Blood pressure and heart rate are measured by means of an inflatable cuff around the tail. Most classes of antihypertensives will be detected. Agents such as beta-adrenergic antagonists will be detected by decreased heart rate. Other rat models include deoxycorticosterone acetate (DOCA)-induced hypertensive, renal hypertensive (one or both renal arteries clamped), and stroke-prone spontaneously hypertensive rats. Hypertensive dogs produced by clamping one or both renal arteries may also be used to test or verify antihypertensive activity in a second species. 

After the skin is cleaned, either a blood pressure cuff or a tourniquet is applied 4 to 6 inches (10 to 15 cm) above the intended puncture site. This obstructs the return of venous blood to the heart and distends the veins. When a blood pressure cuff is used as a tourniquet, it is usually inflated to approximately 60 mm Hg (8.0 kPa). Tourniquets are typically made ft om precut soft rubber strips or from Velcro type of bands. It is rarely necessary to leave a tourniquet in place for longer than 1 minute, but even within this short time the composition of blood changes. Although the changes that occur in 1 minute are slight, marked changes have been observed after 3 minutes (Table 2-1). 

Indirect measurement of BP using a sphygmomanometer is a common routine medical screening tool that should be conducted at every health care encounter. The appropriate procedure to measure BP has been described by the American Heart Association (AHA). It is imperative that the measurement equipment (inflation cuff, stethoscope, manometer) meet certain national standards. These standards use criteria to ensure maximum quality and precision with measurement. 

A properly sized cuff (pediatric, small, regular, large, or extra large) should be used. Overestimating the actual BP can occur if the cuff is too small. The inflatable rubber bladder inside the cuff should encircle at least 80% of the arm, and the width of the cuff should be at least two-thirds the length of the upper arm. 

Close the inflation valve with the thumb and index finger, and inflate the cuff to 70 mm Hg, and then inflate in increments of 10 mm Hg by pumping the inflation bulb (as it is resting in the palm of your hand) with the last three fingers. 

The bell (not the diaphragm) of the stethoscope should be placed on the skin of the antecubital fossa, directly over where the brachial artery is palpated. The stethoscope earpieces should be inserted appropriately. The valve should be closed with the cuff then inflated rapidly to about 30 mm Hg above the estimated SBP from the palpatory method. The value should be opened only slightly to release pressure at a rate of 2 to 3 mm Hg/s. 

Several additional factors can result in erroneous BP measurements. Pseudohypertension is a falsely elevated BP measurement that is seen in elderly patients with a rigid, calcified brachial artery. In these patients, the true arterial BP when measured directly intraarterially (the most accurate measurement of BP) is much lower than that measured using the indirect cuff method. The Osier s maneuver can be used to test for pseudohypertension. In this maneuver, the BP cuff is inflated above peak SBP. If the radial artery remains palpable, the patient has a positive Osier s maneuver (rigid artery), which indicates pseudohypertension. 

Patients with an auscultatory gap may have either underestimated SBP or overestimated DBP measurements. In this situation, as the cuff pressure falls from the true SBP value, the Korotkoff sound may disappear (indicating a false DBP measurement), reappear (a false SBP measurement), and then disappear again at the true DBP value. This is often identified by using the palaptory method to estimate SBP and then inflating the cuff an additional 30 mm Hg above this estimate because the gap is usually less than 30 mm Hg. When an auscultatory gap is present, Korotkoff sounds usually are heard when pressure in the cuff first starts to decrease after inflation. 

Trousseau s sign—A hand spasm produced by placing a blood pressure cuff over the forearm and inflating the pressure above the systolic pressure for 3 minutes. 

Inflate cuff above systolic level by palpating disappearance of radial pulse. 

Trousseim s sign is the most reliublc indication of latent tetany. A sphygmomanometer cuff is inflated to above systolic pressure for at least 2 minutes while observing the hand. A positive respon.se will be the appearance of a typical carpal spasm, which relaxes some 5 seconds or so after the cuff is released. 

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