To distinguish prominent neck veins from those distended because of increased central venous pressure, ascertain whether the veins fill from below.
If you can see fluttering waves in inspiration and expiration, you can be sure that you are looking at the top of the venous column.
Elevated venous pressure can also be discerned from looking at hand veins or sublingual veins, especially in ICU patients when one cannot get an unobstructed view of the neck veins.
From the neck veins, estimate the venous pressure; determine the effect of inspiration (Kussmaul sign) and of pressure on the abdomen (abdominojugular test, also called hepatojugular reflux), and observe the venous pressure waves.
Always have a high index of suspicion for deep venous thrombosis, especially in patients with any feature of the Virchow triad of vein wall damage, stasis, and hypercoagulability.
Begin with the patient relaxing comfortably in bed with the head of the bed elevated between 30 and 45 degrees.
There are two different jugular veins (Fig. 19-1). The internal jugular1 vein is posterior and superior to the medial fourth of the clavicle, running cephalad until it passes under the sternocleidomastoid muscle. (Right above the clavicle, one is actually looking at the inferior jugular bulb, which lies between the clavicular and sternal insertions of the sternocleidomastoid and is where this muscle splits into two heads.) The second vein is the external jugular, which crosses over the top of the sternocleidomastoid muscle. There are advantages to using each.
Perloff considers the internal jugular to be the better vein for pressure estimation and waveform (venous pulsation) analysis. Although the vein itself is generally too deep to be seen, one often sees transmitted pulsations. With extremely high venous pressure, it may be difficult to move a sick patient to a position sufficiently erect to permit a clear view of the internal jugular vein collapse, which is how one determines the venous pressure (vide infra). The external jugular is less often inapparent when compared with the transmitted pulsations of the internal jugular vein and can, moreover, be seen for a longer distance. Therefore, it is more often usable in a bed-bound patient in whom the pressure is extremely high, especially when the internal jugular vein is too short to permit stripping it to be sure there is reflux from below (vide infra). When visible, the pulsations from the internal jugular should be more definitive (vide infra).
I suggest that the neophyte try observing both pulsations. After you have examined 100 patients, you will know which method works for you.
If jugular venous pulsations cannot be seen, lower the top half of the bed until they appear. Be sure to check that both the left and the right external jugular veins distend at approximately the same degree of elevation during the same phase of respiration. If the left external jugular vein is selectively distended, this is a useful diagnostic clue to certain entities to be discussed below. Most use the right jugular veins to make measurements because they take a straighter path into the right atrium and yield less chance of interference with the waveform by ectatic arteries.
In some patients, the jugular veins are inapparent to the clinician even when actually full. To distinguish between inapparent veins and the absence of venous fullness (“distention”) in a given patient, have the patient perform the Valsalva maneuver for about 10 seconds. This will temporarily increase venous pressure to an abnormal degree; if you still cannot see the jugular veins, then they are inapparent (Fig. 19-2, Valsalva panel). Thus, you can make no statement about venous pressure on the basis of the neck veins in this patient and will have to find another method of estimating it, as discussed later in this chapter.
If the veins appear to be spontaneously distended, you must next determine whether they represent the pressure from below or are simply prominent. To do this, strip the vein in the following manner:
Place your adjacent forefingers over a distended segment of the external jugular vein. (The internal jugular vein or bulb does not usually have a visible segment sufficiently long to permit these manipulations.)
FIGURE 19-1 The external jugular vein is seen crossing the sternomastoid. The arrow marks the inferior jugular bulb, visible just above the clavicle between the two heads of the sternomastoid. (David, by Michelangelo.)
Strip the vein of its blood by moving your fingers apart while maintaining firm pressure on the vein. The vein should now be flat as you maintain pressure on it with both fingers.
To test for “filling from below” (from the heart back up into the veins), release only the finger closest to the heart. Maintain the other finger in its place. d. If the central venous pressure is high enough, the vein will fill in a retrograde fashion (“from below”). (Fig. 19-2, stripping panel.)
Of course, if the venous valves were perfectly competent, the vein would not fill in retrograde fashion, but the distention of any vein tends to impair coaptation of the venous valves, so this is almost never a problem.
Take the venous pressure measurement.
Look for the fluttering waves in inspiration or expiration. If you can see them, then you are looking at the top of the venous column, which is analogous to the meniscus in the venous pressure measurement manometer (vide infra). It is helpful to exaggerate the vein by shining a penlight on it obliquely so as to cast a shadow posteriorly on the neck. (This is especially useful for detecting pulsations.)
In order to find the top of the column, it may be necessary to have the head of the bed elevated and depressed several times, repeating the stripping motion each time.
The venous pressure is estimated to be the vertical distance between the top of the blood column (the “fluttering”) and the right atrium. (The angle of the patient and the distance along the vein do not matter.) With the patient supine, the right atrium (the zero reference point, i.e., the point at which the venous pressure is zero) is located in the fourth intercostal space about 35% to 50% of the distance from the sternum to the bed along the anterior-posterior diameter. (To verify this, look at a computed tomography [CT] scan if you have not had the opportunity to look at about 25 cadavers as we did years ago.) The upper limit of normal, by this method, is 16 cm. (For normal values obtained by using other zero reference points, see later in this chapter.)
two other interested observers concluded that the central venous pressure cannot be reliably estimated by inspection of the jugular veins. (Of course, the peripheral and central venous pressures cannot be exactly the same. Otherwise, blood would not flow.) Yet, 90% coincidence could be achieved in that study if one were willing to accept an error of up to 4 cm. Clinically, if one estimates a pressure of 24 cm of water, it does not matter very much whether it is truly 20 or 28 cm. Similarly, if one estimates a pressure of 8 or 10 cm of water, one can be confident that the true value is not above 16 cm (the upper limit of normal). Thus, although not perfect, such an estimation becomes one more brick in the Great Wall of diagnosis.
Wiener and Nathanson (1976-1977) estimate the external jugular venous pressure with the patient supine. The vein is stripped and the meniscus observed after a moderate inspiration. They state that the meniscus in normal people is usually 3.5 cm below the angle of Louis. (Using the cardiologist’s constant, this would give a “normal” pressure of 1.5 cm!) In a patient with very high venous pressure, it would not be possible to see the meniscus during inspiration. Thus, with this method, one could tell that the venous pressure was high but would not know how high. Therefore, do it right. (Elevate the head of the bed for such patients.)
In contemporary intensive care units, it is often difficult for the attending physician to get an unimpeded view of a jugular vein whose vascular connection to the right atrium has not been impeded by medical interventions. Accordingly, it is helpful to use a modification of the Gärtner maneuver (Dennison, 1969). This consists of raising and lowering the hand while stripping its veins until one finds a point of elevation at which they are no longer distended. One then slightly lowers the hand until the veins begin to distend; the vertical distance from this point down to the right atrium is the estimated venous pressure.
epidemic use of the flow-directed balloon-tip (Swan-Ganz) catheter may prove to outweigh its marginal benefits (Angus and Black, 2001; Robin, 1985). A much cheaper and noninvasive set of measurements obtainable at the bedside from the M-mode echocardiogram (Askenazi et al., 1981) has been suggested as a method to supplant the Swan-Ganz for measuring left atrial pressure. (This new technique uses the echocardiographic equivalent of the S2-opening snap interval once used by bedside clinicians to determine the severity of mitral stenosis; see Chapter 17.) While controversy continues, almost 2 million Swan-Ganz catheters were sold in North America in 2003.
Place the supine patient’s right arm on a pillow or towels so that the antecubital vein will be at the zero reference point.
As noted above, the zero reference point used in this text is a point one third to one half the distance from the sternum down to the bed. Many other zero reference points have previously been offered; these are given in Table 19.1.
Which one should be selected? As elsewhere in medicine, one prefers those that take account of the variability in body size and that permit an easy determination. That said, probably any one is satisfactory if you use it consistently and become familiar with its inherent reliability.
Insert a needle attached to a three-way stopcock and a manometer (the same apparatus that is used when performing puncture of the lumbar interspace for obtaining cerebrospinal fluid samples and pressures).
Via the third port of the stopcock, fill the manometer with sterile saline. Allow the saline to flow into the vein until the pressure equilibrates. Alternatively, use sterile 5% sodium citrate, an anticoagulant.
Read the equilibration point when the patient is not coughing, sneezing, or performing a Valsalva maneuver. Note that the pressure normally drops with inspiration. If it increases paradoxically, the patient has a positive Kussmaul sign for constrictive pericarditis (vide infra).
You may wish to perform the test for abdominojugular reflux at this point (vide infra). The advantage of doing this now is that the pressure is directly measured in the manometer, so if the hepatic compression causes an elevation of 3 cm in the venous pressure, it is easy to see irrespective of the patient’s venous anatomy and position in bed (two factors that may complicate the inspection of the jugular veins).
Continue with the circulation time (Appendix 19.1).
TABLE 19.1 Zero reference points previously used for venous pressure measurements
TABLE 19.2 Findings in some diseases of the right heart and pericardium
This sign consists in a distension—with or without pulsation—of the superficial veins of the neck, occurring when firm pressure is exerted over the liver in the direction of the spinal column, and independent of the movements of respiration. A little consideration of the anatomical relations of the parts concerned will suggest the facility with which an impediment may be created to the flow of blood, in either direction, through the vena cava inferior by such a maneuver, especially when the liver is obviously enlarged. It seems to me that the state thus produced is virtually that which obtains as a chronic condition in long-standing and severe cases of tricuspid incompetence as far as regards the tension in the systemic venous system in the immediate vicinity of the heart. Assuming the existence of tricuspid regurgitation and of a source of compression of the vena cava inferior, it is obvious that with each systole an excessive reflux of blood must take place into the vena cava superior and its tributary veins. It may be noted that the question of pulsation, as compared with distension or undulation, is merely one of degree of morbid venous tension. Although the number of cases in which I have observed this phenomenon is certainly limited, I have never failed to elicit it when there was indubitable evidence of tricuspid incompetence; on the other hand, I have hitherto invariably failed to obtain it in other forms of cardiac valvular disease, and in various cases of hepatic enlargement from causes other than passive congestion. I cannot but think that this sign may furnish an important aid to diagnosis in cases where the usual signs of tricuspid regurgitation are ill-developed or in abeyance, and that it may prove a valuable factor in the difficult general problem of prognosis in cases of cardiac disease.
This is the entire article, requiring only two paragraphs and occupying less than one fourth of one page.
Pasteur was unable to obtain this sign in other forms of cardiac valvular disease, so he believed it to be diagnostic of tricuspid insufficiency. (Could it be possible that none of his other patients had heart failure? We should realize that even one of our best colleagues was capable of such a miss, illustrating the truth of Jean de la Bruyere’s statement: “The exact contrary of what is generally believed is often the truth.”)
Position the patient with his trunk initially around 45 degrees from the horizontal, and observe the jugular pulsations during quiet breathing. Alter the position as needed to identify the highest angle of elevation at which these pulsations can be seen. This is the baseline venous pressure. (You will be searching for a 3-cm rise in venous pressure. Accordingly, if the jugular vein is too short to demonstrate such a rise, you may have to crank up the head of the bed so that the vein rises 3 cm on the vertical.)
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