The jugular venous pressure revisited
ABSTRACTAssessment of the jugular venous pressure is often inadequately performed and undervalued. Here, we review the physiologic and anatomic basis for the jugular venous pressure, including the discrepancy between right atrial and central venous pressures. We also describe the correct method of evaluating this clinical finding and review the clinical relevance of the jugular venous pressure, especially its value in assessing the severity and response to treatment of congestive heart failure. Waveforms reflective of specific conditions are also discussed.
KEY POINTS
- If the jugular venous pressure differs from the true right atrial pressure, the jugular venous pressure is always the lower value.
- The jugular venous pressure is useful to observe when diagnosing congestive heart failure and when considering the need for or the adequacy of diuresis.
- The jugular venous wave form is more difficult to observe than its elevation but can yield useful information in the assessment of certain arrhythmias, right-heart conditions, and pericardial disease.
WHICH REFERENCE POINT TO USE?
The two points that can be used as references above which the jugular venous pressure is expressed are the center of the right atrium and the sternal angle. While the former may reflect physiology, the latter is preferred, as it is always visible and has the added advantage of being close to the upper limit of normal, which is about 3 cm above this level.
The difference in height between these two reference points has often been quoted as 5 cm, but this is an underestimate in the body positions used in examination.5 Seth et al6 found a mean of 8 cm at 30° elevation, 9.7 cm at 45°, and 9.8 cm at 60°. The difference also varied between patients, being larger in association with smoking, older age, large body mass index, and large anterior-posterior diameter. These factors should be considered when trying to evaluate the significance of a particular jugular venous pressure.
The junction of the midaxillary line and the fourth left intercostal space (“the phlebostatic point”) has been recommended as a reference point by some, as it is level with the mid-right atrium. However, using the phlebostatic point as a reference position is cumbersome and results in a valid measurement only with the patient in the supine position.7
TECHNIQUE IS VITAL
Close adherence to technical details is vital in reliably and reproducibly measuring the pressure in the internal jugular veins (Figure 1).
The right side is usually observed first, as it is the side on which the examiner usually stands. Using the right side also avoids the rare occurrence of external compression of the left brachiocephalic vein.
Head and shoulders
The sternocleidomastoid muscle lies anterior to each internal jugular vein.8 When tense, it impedes good observation. Shortening, and hence relaxing, this muscle permits the meniscus to be observed. Correct positioning is achieved by:
- Placing a folded pillow behind the patient’s head
- Keeping the shoulders on the mattress
- Turning the head away and elevating the jaw, both slightly; this is often best achieved by gentle pressure of the palm of the observer's hand on the patient's forehead.
Degree of head elevation
Although the proper degree of head elevation is sometimes said to be between 30° and 60°, these numbers are approximate. The correct angle is that which brings the venous meniscus into the window of visibility in the neck between the clavicle and mandible.
Lighting
Shining a flashlight tangentially to the skin is often helpful, casting shadows that improve the visibility of vein motion. Dimming the room lighting may further enhance this effect. Directing a light perpendicular to the skin is not helpful.
Also check the external jugular vein
Checking the external jugular vein can help establish that the jugular venous pressure is normal. If the vein is initially collapsed, light finger pressure at the base of the neck will distend it. If the distention rapidly clears after release of this pressure, the jugular venous pressure is not elevated. However, if external jugular venous distention persists, this does not prove true jugular venous pressure elevation, since it may reflect external compression of the vein by the cervical fascia or delayed blood flow caused by sclerotic venous valves.9 In these instances, the internal jugular pulsation level must be sought.
Jugular venous collapse with inspiration
Collapse of the inferior vena cava with forced inspiration is routinely evaluated during echocardiography as a way to estimate right atrial pressure. This finding has been extrapolated to the jugular veins, wherein the absence of venous collapse during vigorous inspiration or sniffing indicates elevated central venous pressures.10
Distinguishing venous from arterial pulsation
Features indicating venous rather than arterial pulsation were listed by Wood more than 50 years ago11 and are still relevant today. These include internal jugular pulsation that:
- Is soft, diffuse, undulant
- Is not palpable
- Has two crests and two troughs per cardiac cycle
- Has crests that do not coincide with the palpated carotid pulse (exceptions may be seen with the systolic timing of the v wave of tricuspid regurgitation)
- Has higher pressure in expiration, lower in inspiration (exceptions may be seen when Kussmaul physiology is present)
- Has pressure that rises with abdominal pressure
- Is obliterated by light pressure at the base of the neck.
In addition to the above criteria, a wave whose movement is predominantly a descent is nearly always venous.
Abdominojugular reflex
Firm, steady pressure over the abdomen will often result in a small rise in jugular venous pressure. In healthy people, this normalizes in a few seconds, even while manual pressure is maintained. Persistence of jugular venous pressure elevation beyond 10 seconds, followed by an abrupt fall upon withdrawal of manual pressure, is abnormal. This finding has implications similar to those of an elevated baseline jugular venous pressure.
