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Ultrasonography of the internal jugular vein in patients with dyspnea without jugular venous distention on physical examination
IMAGING/BRIEF RESEARCH REPORT
Ultrasonography of the Internal Jugular Vein in Patients With Dyspnea Without Jugular Venous Distention on Physical Examination
Timothy Jang, MD Chandra Aubin, MD, RDMS Rosanne Naunheim, MD Douglas Char, MD
Study objective: Accurate physical examination of patients with dyspnea is important. Jugular venous distention, however, can be difficult to assess in patients. The purpose of this case series is to serve as a pilot study of how ultrasonographic examination of the internal jugular vein compares with other measures of dyspnea.
From the Division of Emergency Medicine, Washington University School of Medicine, St. Louis, MO.
Methods: This was a case series of 8 patients presenting with dyspnea without jugular venous distention on physical examination. Each patient underwent ultrasonographic examination of the internal jugular vein and inferior vena cava by an emergency physician sonographer blinded to all other clinical information after initial evaluation by another emergency physician for dyspnea. Results of ultrasonographic examination of the internal jugular vein and inferior vena cava were subsequently compared with initial emergency physician physical examination findings, initial chest radiography interpreted by radiologists, initial B-type natriuretic peptide levels, and final hospital discharge diagnosis. Results: Ultrasonographic examination of the internal jugular vein compared more favorably with B-type natriuretic peptide levels and chest radiographic findings than ultrasonographic examination of the inferior vena cava in these patients with dyspnea but not jugular venous distention on physical examination. It was able to identify every patient diagnosed with cardiogenic pulmonary edema on hospital discharge. Conclusion: Ultrasonographic examination of the internal jugular vein appears to be helpful in patients who present with dyspnea but do not have evidence of jugular venous distention on physical examination. [Ann Emerg Med. 2004;44:160-168.]
0196-0644/$30.00 Copyright Ó 2003 by the American College of Emergency Physicians. doi:10.1016/ j.annemergmed.2004.03.014
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Jang et al
Editor’s Capsule Summary What is already known on this topic Although jugular venous distention is a classic finding in patients with congestive heart failure, it may be difficult to discern for a variety of reasons. What question this study addressed This small case series (8 patients) used emergency physician– performed ultrasonography to detect jugular venous distention and estimate central venous pressure in patients in whom jugular venous distention could not be detected clinically. Ultrasonographic findings were correlated with other determinates of congestive heart failure. What this study adds to our knowledge Ultrasonography successfully discriminated all patients eventually deemed to have congestive heart failure from those who did not. How this might change clinical practice If confirmed in larger studies, bedside ultrasonography of the internal jugular vein may be more sensitive and accurate than clinical examination in detecting elevated pressure.
INTRODUCTION
An accurate physical examination of patients with congestive heart failure is important but challenging. In 1930, Lewis1 described what we now consider the ‘‘classic’’ signs of congestive heart failure. Since then, assessment of jugular venous distention has been part of the examination of patients with acute dyspnea. Unfortunately, the jugular veins can be difficult to recognize, especially in obese or short-necked patients. Lipton2 described the case of a man with ultrasonography-confirmed jugular venous distention that was missed on physical examination. He further described the process by which central venous pressure could be assessed with ultrasonographic examination of the internal jugular vein.3 A similar, although more complex, method was recently described in the emergency medicine literature by Randazzo et al4 using ultrasonographic examination of the inferior vena cava to assess central venous pressure. The purpose of this pilot study is to determine how ultrasonographic examination of the internal jugular vein compares with other methods to diagnose congestive heart failure in patients who present with dyspnea and no evidence of jugular venous distention on physical examination. MATERIALS AND METHODS
75,000 annual adult visits on 1 of 2 shifts when an emergency physician sonographer (TJ) was in the department as part of an ultrasonographic elective. Treating emergency medicine residents and attending emergency physicians were asked to identify patients presenting with dyspnea without jugular venous distention on physical examination. The emergency physician sonographer then obtained verbal consent from these patients and performed ultrasonographic examination of the internal jugular vein and inferior vena cava for real-time bedside assessment of central venous pressure. Ultrasonographic examination of the internal jugular vein and inferior vena cava were done after the physical examination by the treating emergency physicians but not particularly timed relative to the obtaining of radiographs and laboratory tests. Using a predesigned data sheet, the results of the internal jugular vein and inferior vena cava examinations were subsequently compared with the physical examination findings of the treating emergency physicians, initial chest radiography findings, initial B-type natriuretic peptide levels, ED diagnosis, and final hospital course and discharge diagnosis. Study Populations
All ultrasonographic examinations were done by an emergency physician sonographer on an ultrasonographic elective under the supervision of an emergency physician sonographer certified by the American Registry of Diagnostic Medical Sonographers (CA). The emergency physician sonographer performing these studies had previously performed 1,251 ultrasonographic examinations primarily related to abdominal and obstetric indications, but also including 100 vascular and cardiac examinations. He had also previously performed ultrasonographic examination of the internal jugular vein for line placement but had not previously performed ultrasonographic examination of the internal jugular vein or inferior vena cava for central venous pressure measurement. All patients with dyspnea were eligible for participation if identified by their treating physicians—resident and attending—as not having jugular venous distention on physical examination. Patients were excluded if either physician found jugular venous distention on physical examination. Patients were also excluded if they could not speak English or were otherwise unable to give informed consent. Body habitus was not an exclusion criterion.
Study Protocol
Study Measurements
This was a case series of patients conveniently sampled at an urban, academic emergency department (ED) with
Ultrasonographic examination of the internal jugular vein was done using an Aloka SSD 1400 (Aloka Co., Ltd.,
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Tokyo, Japan) with a 7.5-MHz linear array probe and consisted of transverse and longitudinal views of the neck (Figures 1 and 2) for identification of the internal jugular vein and common carotid artery with the patient reclined at 45 degrees. Once the vessels were identified, the meniscal levels were identified using the transverse (Figure 3) and longitudinal views (Figure 2) with the patient at end-expiration as described by Lipton.3 The height was then measured from the sternal notch, and 5 cm was added for a final jugular venous pressure in centimeters of H2O. The average of the transverse and longitudinal measurements was used for the final value of internal jugular vein central venous pressure. If the meniscus could not be identified at 45 degrees, then the patient was reclined until the meniscus could be identified, as previously described by Lipton.2,3 If the patient could not tolerate being reclined and the meniscus could be identified with the patient sitting upright, then the meniscus was identified and measured as described by Lipton.2,3 Ultrasonographic examination of the inferior vena cava was done using an Aloka SSD 1400 (Aloka Co., Ltd.) with a 5.0-MHz curved linear array probe and involved identification of the inferior vena cava in the subxiphoid area, followed by observation of variations in diameter with respiration in transverse and longitudinal views.
Central venous pressure was determined as ‘‘low,’’ ‘‘medium,’’ or ‘‘high’’ according to the protocol of Randazzo et al.4 In particular, greater than 50% collapse of the inferior vena cava with inspiration was accepted as evidence of low central venous pressure, an increase in inferior vena cava diameter equal to or greater than 50% was used to categorize a medium central venous pressure, and a respiratory decrease of inferior vena cava diameter of less than 50% was used to categorize an elevated central venous pressure. The emergency physician sonographer was blinded to all patient data until after the ultrasonographic examination was performed, and results were recorded on a predesigned data sheet. To avoid systematic bias of one ultrasonographic examination measurement on the other, odd-numbered patients had their inferior vena cava examined first, and even-numbered patients had their internal jugular vein examined first. The results of ultrasonographic examination for each patient were compared with (1) the initial physical examination findings recorded on resident and attending medical records; (2) initial chest radiographic findings, as interpreted by an attending radiologist; (3) initial B-type natriuretic peptide levels as determined by the Bayer Centaur chemiluminescent immunoassay (Bayer Diagnostics, Kansas City, MO) with a normal range of less than 100 pg/mL; (4) ED
Figure 1. Transverse view of the right side of the neck with the patient at 45 degrees. The internal jugular vein (IJ) is seen lying above the common carotid artery (CCA). The sternocleidomastoid is seen over the internal jugular vein and common carotid artery.
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diagnosis recorded in the ED computer tracking database; and (5) the final hospital course and discharge diagnosis, as determined by review of dictated discharge summaries by one of the authors (TJ) who was not blinded to the results of the other findings. The absence of jugular venous distention had to be documented by the resident and attending physician for inclusion in this case series, but the presence of rales, abnormal heart sounds, and peripheral edema simply had to be documented by at least 1 of the treating emergency physicians, which was done to ensure that the dyspneic patients truly did not have jugular venous distention while allowing for comparison to the greatest breadth of possible examination findings. Data Analysis
Data were maintained on a Microsoft Excel worksheet (Microsoft Corporation, Redmond, WA). This study was small and meant to be descriptive; however, we did compare ultrasonographic examination results with the discharge diagnosis (reference standard for congestive heart failure) to determine sensitivity and specificity for the diagnosis of congestive heart failure. We also performed a Pearson correlation between internal jugular vein ultrasonographic examination and B-type natriuretic peptide levels. This study was approved by expedited
review by the human subjects committee of our institution.
RESULTS
All patients who were identified for inclusion consented to participate. The case history, examination findings, chest radiographic findings, B-type natriuretic peptide levels, and ultrasonographic examination results are shown in the Table for the 8 patients enrolled in our series. Of the 8 patients, 4 (patients 5, 6, 7, and 8) had evidence of congestive heart failure according to B-type natriuretic peptide level greater than 500 pg/mL, echocardiography, and discharge diagnosis. An additional patient (patient 4) had a probable diagnosis of congestive heart failure. Ultrasonographic examination of the internal jugular vein showed an elevated central venous pressure (12 cm H2O) in all 5 of these patients (sensitivity 100%, 95% confidence interval [CI] 46.3% to 100%; specificity 100%, 95% CI 31.0% to 100.0%) with an overall correlation of 0.67 (P=.035) with B-type natriuretic peptide levels. Two of these 5 patients had a low central venous pressure by inferior vena cava ultrasonographic examination (Table). The sensitivity for congestive heart failure with ultrasonographic examination of the inferior vena cava was, thus,
Figure 2. Longitudinal view of the right side of the neck showing the meniscal point of the internal jugular vein.
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60% (95% CI 17.0% to 92.7%), with a specificity of 100% (95% CI 31.0% to 100.0%). No patient had a high central venous pressure according to the inferior vena cava ultrasonographic examination. Using a cutoff of 10 cm H2O for defining congestive heart failure by internal jugular vein ultrasonographic examination and a level of at least moderate for defining congestive heart failure by inferior vena cava ultrasonographic examination, neither test was associated with a false-positive result in this series of patients. LIMITATIONS
This case series had several limitations. First, although meeting the training guidelines of the Society for Academic Emergency Medicine, the emergency physician sonographer for this series had limited experience with ultrasonographic examination for central venous pressure. It is possible that greater experience with the inferior vena cava ultrasonographic examination method would have led to a lower error rate, although the error rate reported was consistent with that of previous work.4 Likewise, we are unaware of any study on the interrater reliability of either method, thus making it difficult to say how this would have affected our findings.
Second, the emergency physician sonographer was not truly blinded to all clinical characteristics because seeing patients allowed for an assessment of their level of respiratory distress, which could have biased the interpretation of ultrasonographic examination findings. This bias could be improved in future studies by having a separate clinician interpret the ultrasonographic examination images or by having multiple operators perform the same study on the same patient. Third, this pilot study involved a small convenience sample and series of patients, and only one emergency physician sonographer performed the ultrasonographic examinations. Because there has been only one study of emergency physicians using the inferior vena cava ultrasonographic examination method4 and we are unaware of any studies on the internal jugular vein ultrasonographic examination method, it is impossible to say how other emergency physician sonographers would have performed in a prospective study of consecutive patients. This performance could be the subject of future studies looking at interrater reliability, accuracy of either method, and the usefulness of the tests in larger populations. Fourth, a definitive criterion standard such as pulmonary artery catheter data was not used in this study. It was not feasible in our sample but could be done in future
Figure 3. In the transverse view of the meniscal level, the internal jugular vein (IJ) is seen collapsed, overlying the still-patent common carotid artery (CCA).
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Table.
Brief summary of patients.
Patient No. 1
2
3
4
5
6
7
8
Case History
Examination Findings
Chest Radiography Findings
84-year-old Expiratory Mild patient with history wheezes cardiomegaly of hypertension, without rales without CHF, and CAD or peripheral evidence of presenting with edema edema 1 day of increasing dyspnea 51-year-old patient Bibasilar rales Moderate with history of with trace cardiomegaly hypertension, CHF, peripheral without and breast cancer edema evidence presenting with of edema 2 days of constant dyspnea 74-year-old patient Bilateral rales Bibasilar with history of in the lower atelectasis hypertension fields, no S3 with mild presenting or peripheral cardiomegaly postsyncope edema but no edema with 1 day of worsening dyspnea 50-year-old patient Clear breath Mild with history of sounds without cardiomegaly hypertension and peripheral without CHF presenting edema evidence with 1 day of of edema worsening dyspnea 58-year-old patient Decreased Mild with history of CAD, basilar breath effusion with previous MI, and sounds with cardiomegaly CHF presenting 1+ peripheral with 12 hours edema but of dyspnea no rales 85-year-old patient Bibasilar rales Pulmonary with history of with 1+ vascular hypertension and peripheral redistribution CHF presenting edema with moderate with several days edema of dyspnea and chest pain 70-year-old patient Moderate Moderate with history expiratory pulmonary edema of COPD and wheeze without with normal hypertension rales or cardiac size presenting with peripheral worsening wheeze edema 32-year-old patient Bibasilar rales Mild perihilar with history of without infiltrate hypertension, ESRD peripheral with mild on hemodialysis, edema cardiomegaly and CHF presenting with dyspnea after dialysis
IJ IVC Ultrasonographic BNP Ultrasonographic Examination Level, pg/mL Examination CVP, cm H2O
ED Diagnosis
Final Hospital Diagnosis/Course
66
Low
<5
Dyspnea with Angina, treated with hypokalemia nitrates and b-blockers
74
Low
6
Dyspnea with chest pain
285
Low
8.3
Syncope and Syncope, ruled out hypertension for myocardial infarction
439
Low
12.1
Dyspnea
Acute renal failure and severe left ventricular dysfunction
699
Low
15.3
Dyspnea with CAD
CHF exacerbation, treated with diuretics
833
Moderate
15.5
Dyspnea and pneumonia
Cardiogenic shock with ejection fraction <25%
1,049
Moderate
14.6
COPD-bronchitis COPD with flash pulmonary edema, treated with nebulizers and diuretics
2,750
Moderate
15.3
Dyspnea and CHF
Pulmonary embolism treated with anticoagulants
Pulmonary edema due to left ventricular dysfunction and sepsis
BNP, B-type natriuretic peptide; IVC, inferior vena cava; IJ, internal jugular vein; CVP, central venous pressure; CHF, congestive heart failure; CAD, coronary artery disease; MI, myocardial infarction; COPD, chronic obstructive pulmonary disease; ESRD, end-stage renal disease.
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Figure 4. Nondistended internal jugular vein (IJ) of patient 2.
Figure 5. Distended internal jugular vein (IJ) of patient 6.
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studies using patients admitted to the ICU, with invasive catheters used for hemodynamic monitoring. Finally, timing of the ultrasonographic examinations was not standardized relative to the attainment of diagnostic tests such as the B-type natriuretic peptide level and chest radiography or therapeutic interventions such as the administration of furosemide. However, because all ultrasonographic examinations were done in the ED after emergency physician evaluation, it is likely that our findings would persist in a prospective study requiring ultrasonographic examination before procurement of laboratory study results and radiographs.
DISCUSSION
As stated previously, meniscal levels of the internal jugular vein were used to determine jugular venous distention and central venous pressure. Figure 4 demonstrates the undistended internal jugular vein of patient 2, obtained with the patient reclining at 10 degrees. Figure 5 demonstrates the distended internal jugular vein in patient 6, who was sitting upright. Using B-type natriuretic peptide and final hospital discharge diagnosis (with positive echocardiography results in all cases) as reference standards, estimation of the central venous pressure by inferior vena cava ultrasonographic examination had a sensitivity of 60%, consistent with the recent study by Randazzo et al4 and other studies using pulmonary artery catheter data as a criterion standard.5-7 Sensitivity would have been even lower if moderate elevations of central venous pressure had not been considered diagnostic for congestive heart failure. In contrast, an elevated central venous pressure as determined by ultrasonographic examination of the internal jugular vein correlated with B-type natriuretic peptide in all 8 patients (r=0.67). Comparing the 2 ultrasonographic examination estimates of central venous pressure, the inferior vena cava ultrasonographic examination method would have misidentified 2 patients (patients 4 and 5) with dyspnea caused by congestive heart failure, whereas the internal jugular vein ultrasonographic examination method would have identified all of them. Specificity in this small study appeared to be comparable between the 2 methods. Both ultrasonographic examination estimates of central venous pressure would have predicted patients with pulmonary edema demonstrated on chest radiography. It may be that either ultrasonographic examination test would be more sensitive than standard chest radiography in identifying
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cardiogenic pulmonary edema, which could be the subject of future studies. Although B-type natriuretic peptide levels are part of the European guidelines for the evaluation of heart failure8 and have been described as ‘‘more accurate than any finding in the history, physical examination, or laboratory analyses in delineating the cause of dyspnea,’’8 their role in US clinical practice is still being developed. The American College of Cardiology/American Heart Association guidelines on heart failure state that B-type natriuretic peptide ‘‘may have utility in the urgent-care setting’’ but caution that ‘‘more research will be necessary to determine its role in both diagnosis and management.’’9 The comparison of ultrasonographic examination results to B-type natriuretic peptide provides an interesting look at what may become a reference standard in the diagnosis of congestive heart failure. The ultrasonographic examination of the internal jugular vein seemed to be less cumbersome than inferior vena cava ultrasonographic examination because examination of the internal jugular vein avoided the difficulty of scanning through bowel gas and the need to make estimates of changes with respiration. However, it may simply be that our inexperience with the inferior vena cava ultrasonographic examination made it more cumbersome. Several areas for further research are suggested by this small pilot study. A larger study is required to further define the optimum cutoff value to maximize the sensitivity and specificity of this technique for detecting congestive heart failure. There is also a need to investigate how much training is necessary to acquire competency to reliably perform this examination, as well as to determine whether there are subsets of patients for whom this technique would not be reliable. Finally, would the use of ultrasonographic examination– determined jugular venous distention allow for better triage, treatment, and outcomes of patients presenting to the ED with dyspnea? In conclusion, ultrasonographic examination of the internal jugular vein appears to be helpful in the examination of patients with dyspnea who do not have jugular venous distention on physical examination. It may be easier to perform than ultrasonographic examination of the inferior vena cava and more sensitive for detecting dyspnea caused by cardiogenic pulmonary edema. Author contributions: TJ performed the ultrasonographic examinations for this study. CA, RN, and DC assisted with case series concept design and provided editorial review. TJ takes responsibility for the paper as a whole.
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Received for publication December 22, 2003. Revisions received February 10, 2004, and March 5, 2004. Accepted for publication March 9, 2004. The authors report this study did not receive any outside funding or support. Reprints not available from the authors. Address for correspondence: Timothy Jang, MD, Division of Emergency Medicine, Washington University School of Medicine, Campus Box 8072, St. Louis, MO 63110; 314-362-9177, fax 314-3620478; E-mail [email protected].
REFERENCES 1. Lewis T. Early signs of cardiac failure of the congestive type. BMJ. 1930;1:849-852. 2. Lipton B. Determination of elevated jugular venous pressure by real-time ultrasound [letter]. Ann Emerg Med. 1999;34:115. 3. Lipton B. Estimation of central venous pressure by ultrasound of the internal jugular vein. Am J Emerg Med. 2000;18:432-434. 4. Randazzo MR, Snoey ER, Levitt MA, et al. Accuracy of emergency physician assessment of left ventricular ejection fraction and central venous pressure using echocardiography. Acad Emerg Med. 2003;10:973-977. 5. Jue J, Chung W, Schiller NB. Does inferior vena cava size predict right atrial pressures in patients receiving mechanical ventilation? J Am Soc Echocardiogr. 1992;5: 613-619. 6. Machraoui A, Von Dryander S, Hinrichsen M, et al. Two-dimensional echocardiographic assessment of right cardiac pressure overload in patients with chronic obstructive airway disease. Respiration. 1993;60:65-73. 7. Stein J, Neumann A, Marcus R. Comparison of estimates of right atrial pressure by physical examination and echocardiography in patients with congestive heart failure and reasons for discrepancies. Am J Cardiol. 1997;80:1615-1618. 8. Zolty R. B-natriuretic peptide, a new tool for managing congestive heart failure. Primary Care Case Rev. 2003;6:21-28. 9. ACC/AHA guidelines for the evaluation and management of chronic heart failure in the adult: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (committee to revise the 1995 Guidelines for the Evaluation and Management of Heart Failure). J Am Coll Cardiol. 2001;38:2101-2113.
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Ultrasonography of the Internal Jugular Vein in Patients With Dyspnea Without Jugular Venous Distention on Physical Examination
Timothy Jang, MD Chandra Aubin, MD, RDMS Rosanne Naunheim, MD Douglas Char, MD
Study objective: Accurate physical examination of patients with dyspnea is important. Jugular venous distention, however, can be difficult to assess in patients. The purpose of this case series is to serve as a pilot study of how ultrasonographic examination of the internal jugular vein compares with other measures of dyspnea.
From the Division of Emergency Medicine, Washington University School of Medicine, St. Louis, MO.
Methods: This was a case series of 8 patients presenting with dyspnea without jugular venous distention on physical examination. Each patient underwent ultrasonographic examination of the internal jugular vein and inferior vena cava by an emergency physician sonographer blinded to all other clinical information after initial evaluation by another emergency physician for dyspnea. Results of ultrasonographic examination of the internal jugular vein and inferior vena cava were subsequently compared with initial emergency physician physical examination findings, initial chest radiography interpreted by radiologists, initial B-type natriuretic peptide levels, and final hospital discharge diagnosis. Results: Ultrasonographic examination of the internal jugular vein compared more favorably with B-type natriuretic peptide levels and chest radiographic findings than ultrasonographic examination of the inferior vena cava in these patients with dyspnea but not jugular venous distention on physical examination. It was able to identify every patient diagnosed with cardiogenic pulmonary edema on hospital discharge. Conclusion: Ultrasonographic examination of the internal jugular vein appears to be helpful in patients who present with dyspnea but do not have evidence of jugular venous distention on physical examination. [Ann Emerg Med. 2004;44:160-168.]
0196-0644/$30.00 Copyright Ó 2003 by the American College of Emergency Physicians. doi:10.1016/ j.annemergmed.2004.03.014
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Jang et al
Editor’s Capsule Summary What is already known on this topic Although jugular venous distention is a classic finding in patients with congestive heart failure, it may be difficult to discern for a variety of reasons. What question this study addressed This small case series (8 patients) used emergency physician– performed ultrasonography to detect jugular venous distention and estimate central venous pressure in patients in whom jugular venous distention could not be detected clinically. Ultrasonographic findings were correlated with other determinates of congestive heart failure. What this study adds to our knowledge Ultrasonography successfully discriminated all patients eventually deemed to have congestive heart failure from those who did not. How this might change clinical practice If confirmed in larger studies, bedside ultrasonography of the internal jugular vein may be more sensitive and accurate than clinical examination in detecting elevated pressure.
INTRODUCTION
An accurate physical examination of patients with congestive heart failure is important but challenging. In 1930, Lewis1 described what we now consider the ‘‘classic’’ signs of congestive heart failure. Since then, assessment of jugular venous distention has been part of the examination of patients with acute dyspnea. Unfortunately, the jugular veins can be difficult to recognize, especially in obese or short-necked patients. Lipton2 described the case of a man with ultrasonography-confirmed jugular venous distention that was missed on physical examination. He further described the process by which central venous pressure could be assessed with ultrasonographic examination of the internal jugular vein.3 A similar, although more complex, method was recently described in the emergency medicine literature by Randazzo et al4 using ultrasonographic examination of the inferior vena cava to assess central venous pressure. The purpose of this pilot study is to determine how ultrasonographic examination of the internal jugular vein compares with other methods to diagnose congestive heart failure in patients who present with dyspnea and no evidence of jugular venous distention on physical examination. MATERIALS AND METHODS
75,000 annual adult visits on 1 of 2 shifts when an emergency physician sonographer (TJ) was in the department as part of an ultrasonographic elective. Treating emergency medicine residents and attending emergency physicians were asked to identify patients presenting with dyspnea without jugular venous distention on physical examination. The emergency physician sonographer then obtained verbal consent from these patients and performed ultrasonographic examination of the internal jugular vein and inferior vena cava for real-time bedside assessment of central venous pressure. Ultrasonographic examination of the internal jugular vein and inferior vena cava were done after the physical examination by the treating emergency physicians but not particularly timed relative to the obtaining of radiographs and laboratory tests. Using a predesigned data sheet, the results of the internal jugular vein and inferior vena cava examinations were subsequently compared with the physical examination findings of the treating emergency physicians, initial chest radiography findings, initial B-type natriuretic peptide levels, ED diagnosis, and final hospital course and discharge diagnosis. Study Populations
All ultrasonographic examinations were done by an emergency physician sonographer on an ultrasonographic elective under the supervision of an emergency physician sonographer certified by the American Registry of Diagnostic Medical Sonographers (CA). The emergency physician sonographer performing these studies had previously performed 1,251 ultrasonographic examinations primarily related to abdominal and obstetric indications, but also including 100 vascular and cardiac examinations. He had also previously performed ultrasonographic examination of the internal jugular vein for line placement but had not previously performed ultrasonographic examination of the internal jugular vein or inferior vena cava for central venous pressure measurement. All patients with dyspnea were eligible for participation if identified by their treating physicians—resident and attending—as not having jugular venous distention on physical examination. Patients were excluded if either physician found jugular venous distention on physical examination. Patients were also excluded if they could not speak English or were otherwise unable to give informed consent. Body habitus was not an exclusion criterion.
Study Protocol
Study Measurements
This was a case series of patients conveniently sampled at an urban, academic emergency department (ED) with
Ultrasonographic examination of the internal jugular vein was done using an Aloka SSD 1400 (Aloka Co., Ltd.,
AUGUST 2004
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Tokyo, Japan) with a 7.5-MHz linear array probe and consisted of transverse and longitudinal views of the neck (Figures 1 and 2) for identification of the internal jugular vein and common carotid artery with the patient reclined at 45 degrees. Once the vessels were identified, the meniscal levels were identified using the transverse (Figure 3) and longitudinal views (Figure 2) with the patient at end-expiration as described by Lipton.3 The height was then measured from the sternal notch, and 5 cm was added for a final jugular venous pressure in centimeters of H2O. The average of the transverse and longitudinal measurements was used for the final value of internal jugular vein central venous pressure. If the meniscus could not be identified at 45 degrees, then the patient was reclined until the meniscus could be identified, as previously described by Lipton.2,3 If the patient could not tolerate being reclined and the meniscus could be identified with the patient sitting upright, then the meniscus was identified and measured as described by Lipton.2,3 Ultrasonographic examination of the inferior vena cava was done using an Aloka SSD 1400 (Aloka Co., Ltd.) with a 5.0-MHz curved linear array probe and involved identification of the inferior vena cava in the subxiphoid area, followed by observation of variations in diameter with respiration in transverse and longitudinal views.
Central venous pressure was determined as ‘‘low,’’ ‘‘medium,’’ or ‘‘high’’ according to the protocol of Randazzo et al.4 In particular, greater than 50% collapse of the inferior vena cava with inspiration was accepted as evidence of low central venous pressure, an increase in inferior vena cava diameter equal to or greater than 50% was used to categorize a medium central venous pressure, and a respiratory decrease of inferior vena cava diameter of less than 50% was used to categorize an elevated central venous pressure. The emergency physician sonographer was blinded to all patient data until after the ultrasonographic examination was performed, and results were recorded on a predesigned data sheet. To avoid systematic bias of one ultrasonographic examination measurement on the other, odd-numbered patients had their inferior vena cava examined first, and even-numbered patients had their internal jugular vein examined first. The results of ultrasonographic examination for each patient were compared with (1) the initial physical examination findings recorded on resident and attending medical records; (2) initial chest radiographic findings, as interpreted by an attending radiologist; (3) initial B-type natriuretic peptide levels as determined by the Bayer Centaur chemiluminescent immunoassay (Bayer Diagnostics, Kansas City, MO) with a normal range of less than 100 pg/mL; (4) ED
Figure 1. Transverse view of the right side of the neck with the patient at 45 degrees. The internal jugular vein (IJ) is seen lying above the common carotid artery (CCA). The sternocleidomastoid is seen over the internal jugular vein and common carotid artery.
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diagnosis recorded in the ED computer tracking database; and (5) the final hospital course and discharge diagnosis, as determined by review of dictated discharge summaries by one of the authors (TJ) who was not blinded to the results of the other findings. The absence of jugular venous distention had to be documented by the resident and attending physician for inclusion in this case series, but the presence of rales, abnormal heart sounds, and peripheral edema simply had to be documented by at least 1 of the treating emergency physicians, which was done to ensure that the dyspneic patients truly did not have jugular venous distention while allowing for comparison to the greatest breadth of possible examination findings. Data Analysis
Data were maintained on a Microsoft Excel worksheet (Microsoft Corporation, Redmond, WA). This study was small and meant to be descriptive; however, we did compare ultrasonographic examination results with the discharge diagnosis (reference standard for congestive heart failure) to determine sensitivity and specificity for the diagnosis of congestive heart failure. We also performed a Pearson correlation between internal jugular vein ultrasonographic examination and B-type natriuretic peptide levels. This study was approved by expedited
review by the human subjects committee of our institution.
RESULTS
All patients who were identified for inclusion consented to participate. The case history, examination findings, chest radiographic findings, B-type natriuretic peptide levels, and ultrasonographic examination results are shown in the Table for the 8 patients enrolled in our series. Of the 8 patients, 4 (patients 5, 6, 7, and 8) had evidence of congestive heart failure according to B-type natriuretic peptide level greater than 500 pg/mL, echocardiography, and discharge diagnosis. An additional patient (patient 4) had a probable diagnosis of congestive heart failure. Ultrasonographic examination of the internal jugular vein showed an elevated central venous pressure (12 cm H2O) in all 5 of these patients (sensitivity 100%, 95% confidence interval [CI] 46.3% to 100%; specificity 100%, 95% CI 31.0% to 100.0%) with an overall correlation of 0.67 (P=.035) with B-type natriuretic peptide levels. Two of these 5 patients had a low central venous pressure by inferior vena cava ultrasonographic examination (Table). The sensitivity for congestive heart failure with ultrasonographic examination of the inferior vena cava was, thus,
Figure 2. Longitudinal view of the right side of the neck showing the meniscal point of the internal jugular vein.
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60% (95% CI 17.0% to 92.7%), with a specificity of 100% (95% CI 31.0% to 100.0%). No patient had a high central venous pressure according to the inferior vena cava ultrasonographic examination. Using a cutoff of 10 cm H2O for defining congestive heart failure by internal jugular vein ultrasonographic examination and a level of at least moderate for defining congestive heart failure by inferior vena cava ultrasonographic examination, neither test was associated with a false-positive result in this series of patients. LIMITATIONS
This case series had several limitations. First, although meeting the training guidelines of the Society for Academic Emergency Medicine, the emergency physician sonographer for this series had limited experience with ultrasonographic examination for central venous pressure. It is possible that greater experience with the inferior vena cava ultrasonographic examination method would have led to a lower error rate, although the error rate reported was consistent with that of previous work.4 Likewise, we are unaware of any study on the interrater reliability of either method, thus making it difficult to say how this would have affected our findings.
Second, the emergency physician sonographer was not truly blinded to all clinical characteristics because seeing patients allowed for an assessment of their level of respiratory distress, which could have biased the interpretation of ultrasonographic examination findings. This bias could be improved in future studies by having a separate clinician interpret the ultrasonographic examination images or by having multiple operators perform the same study on the same patient. Third, this pilot study involved a small convenience sample and series of patients, and only one emergency physician sonographer performed the ultrasonographic examinations. Because there has been only one study of emergency physicians using the inferior vena cava ultrasonographic examination method4 and we are unaware of any studies on the internal jugular vein ultrasonographic examination method, it is impossible to say how other emergency physician sonographers would have performed in a prospective study of consecutive patients. This performance could be the subject of future studies looking at interrater reliability, accuracy of either method, and the usefulness of the tests in larger populations. Fourth, a definitive criterion standard such as pulmonary artery catheter data was not used in this study. It was not feasible in our sample but could be done in future
Figure 3. In the transverse view of the meniscal level, the internal jugular vein (IJ) is seen collapsed, overlying the still-patent common carotid artery (CCA).
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Table.
Brief summary of patients.
Patient No. 1
2
3
4
5
6
7
8
Case History
Examination Findings
Chest Radiography Findings
84-year-old Expiratory Mild patient with history wheezes cardiomegaly of hypertension, without rales without CHF, and CAD or peripheral evidence of presenting with edema edema 1 day of increasing dyspnea 51-year-old patient Bibasilar rales Moderate with history of with trace cardiomegaly hypertension, CHF, peripheral without and breast cancer edema evidence presenting with of edema 2 days of constant dyspnea 74-year-old patient Bilateral rales Bibasilar with history of in the lower atelectasis hypertension fields, no S3 with mild presenting or peripheral cardiomegaly postsyncope edema but no edema with 1 day of worsening dyspnea 50-year-old patient Clear breath Mild with history of sounds without cardiomegaly hypertension and peripheral without CHF presenting edema evidence with 1 day of of edema worsening dyspnea 58-year-old patient Decreased Mild with history of CAD, basilar breath effusion with previous MI, and sounds with cardiomegaly CHF presenting 1+ peripheral with 12 hours edema but of dyspnea no rales 85-year-old patient Bibasilar rales Pulmonary with history of with 1+ vascular hypertension and peripheral redistribution CHF presenting edema with moderate with several days edema of dyspnea and chest pain 70-year-old patient Moderate Moderate with history expiratory pulmonary edema of COPD and wheeze without with normal hypertension rales or cardiac size presenting with peripheral worsening wheeze edema 32-year-old patient Bibasilar rales Mild perihilar with history of without infiltrate hypertension, ESRD peripheral with mild on hemodialysis, edema cardiomegaly and CHF presenting with dyspnea after dialysis
IJ IVC Ultrasonographic BNP Ultrasonographic Examination Level, pg/mL Examination CVP, cm H2O
ED Diagnosis
Final Hospital Diagnosis/Course
66
Low
<5
Dyspnea with Angina, treated with hypokalemia nitrates and b-blockers
74
Low
6
Dyspnea with chest pain
285
Low
8.3
Syncope and Syncope, ruled out hypertension for myocardial infarction
439
Low
12.1
Dyspnea
Acute renal failure and severe left ventricular dysfunction
699
Low
15.3
Dyspnea with CAD
CHF exacerbation, treated with diuretics
833
Moderate
15.5
Dyspnea and pneumonia
Cardiogenic shock with ejection fraction <25%
1,049
Moderate
14.6
COPD-bronchitis COPD with flash pulmonary edema, treated with nebulizers and diuretics
2,750
Moderate
15.3
Dyspnea and CHF
Pulmonary embolism treated with anticoagulants
Pulmonary edema due to left ventricular dysfunction and sepsis
BNP, B-type natriuretic peptide; IVC, inferior vena cava; IJ, internal jugular vein; CVP, central venous pressure; CHF, congestive heart failure; CAD, coronary artery disease; MI, myocardial infarction; COPD, chronic obstructive pulmonary disease; ESRD, end-stage renal disease.
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Figure 4. Nondistended internal jugular vein (IJ) of patient 2.
Figure 5. Distended internal jugular vein (IJ) of patient 6.
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studies using patients admitted to the ICU, with invasive catheters used for hemodynamic monitoring. Finally, timing of the ultrasonographic examinations was not standardized relative to the attainment of diagnostic tests such as the B-type natriuretic peptide level and chest radiography or therapeutic interventions such as the administration of furosemide. However, because all ultrasonographic examinations were done in the ED after emergency physician evaluation, it is likely that our findings would persist in a prospective study requiring ultrasonographic examination before procurement of laboratory study results and radiographs.
DISCUSSION
As stated previously, meniscal levels of the internal jugular vein were used to determine jugular venous distention and central venous pressure. Figure 4 demonstrates the undistended internal jugular vein of patient 2, obtained with the patient reclining at 10 degrees. Figure 5 demonstrates the distended internal jugular vein in patient 6, who was sitting upright. Using B-type natriuretic peptide and final hospital discharge diagnosis (with positive echocardiography results in all cases) as reference standards, estimation of the central venous pressure by inferior vena cava ultrasonographic examination had a sensitivity of 60%, consistent with the recent study by Randazzo et al4 and other studies using pulmonary artery catheter data as a criterion standard.5-7 Sensitivity would have been even lower if moderate elevations of central venous pressure had not been considered diagnostic for congestive heart failure. In contrast, an elevated central venous pressure as determined by ultrasonographic examination of the internal jugular vein correlated with B-type natriuretic peptide in all 8 patients (r=0.67). Comparing the 2 ultrasonographic examination estimates of central venous pressure, the inferior vena cava ultrasonographic examination method would have misidentified 2 patients (patients 4 and 5) with dyspnea caused by congestive heart failure, whereas the internal jugular vein ultrasonographic examination method would have identified all of them. Specificity in this small study appeared to be comparable between the 2 methods. Both ultrasonographic examination estimates of central venous pressure would have predicted patients with pulmonary edema demonstrated on chest radiography. It may be that either ultrasonographic examination test would be more sensitive than standard chest radiography in identifying
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cardiogenic pulmonary edema, which could be the subject of future studies. Although B-type natriuretic peptide levels are part of the European guidelines for the evaluation of heart failure8 and have been described as ‘‘more accurate than any finding in the history, physical examination, or laboratory analyses in delineating the cause of dyspnea,’’8 their role in US clinical practice is still being developed. The American College of Cardiology/American Heart Association guidelines on heart failure state that B-type natriuretic peptide ‘‘may have utility in the urgent-care setting’’ but caution that ‘‘more research will be necessary to determine its role in both diagnosis and management.’’9 The comparison of ultrasonographic examination results to B-type natriuretic peptide provides an interesting look at what may become a reference standard in the diagnosis of congestive heart failure. The ultrasonographic examination of the internal jugular vein seemed to be less cumbersome than inferior vena cava ultrasonographic examination because examination of the internal jugular vein avoided the difficulty of scanning through bowel gas and the need to make estimates of changes with respiration. However, it may simply be that our inexperience with the inferior vena cava ultrasonographic examination made it more cumbersome. Several areas for further research are suggested by this small pilot study. A larger study is required to further define the optimum cutoff value to maximize the sensitivity and specificity of this technique for detecting congestive heart failure. There is also a need to investigate how much training is necessary to acquire competency to reliably perform this examination, as well as to determine whether there are subsets of patients for whom this technique would not be reliable. Finally, would the use of ultrasonographic examination– determined jugular venous distention allow for better triage, treatment, and outcomes of patients presenting to the ED with dyspnea? In conclusion, ultrasonographic examination of the internal jugular vein appears to be helpful in the examination of patients with dyspnea who do not have jugular venous distention on physical examination. It may be easier to perform than ultrasonographic examination of the inferior vena cava and more sensitive for detecting dyspnea caused by cardiogenic pulmonary edema. Author contributions: TJ performed the ultrasonographic examinations for this study. CA, RN, and DC assisted with case series concept design and provided editorial review. TJ takes responsibility for the paper as a whole.
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Received for publication December 22, 2003. Revisions received February 10, 2004, and March 5, 2004. Accepted for publication March 9, 2004. The authors report this study did not receive any outside funding or support. Reprints not available from the authors. Address for correspondence: Timothy Jang, MD, Division of Emergency Medicine, Washington University School of Medicine, Campus Box 8072, St. Louis, MO 63110; 314-362-9177, fax 314-3620478; E-mail [email protected].
REFERENCES 1. Lewis T. Early signs of cardiac failure of the congestive type. BMJ. 1930;1:849-852. 2. Lipton B. Determination of elevated jugular venous pressure by real-time ultrasound [letter]. Ann Emerg Med. 1999;34:115. 3. Lipton B. Estimation of central venous pressure by ultrasound of the internal jugular vein. Am J Emerg Med. 2000;18:432-434. 4. Randazzo MR, Snoey ER, Levitt MA, et al. Accuracy of emergency physician assessment of left ventricular ejection fraction and central venous pressure using echocardiography. Acad Emerg Med. 2003;10:973-977. 5. Jue J, Chung W, Schiller NB. Does inferior vena cava size predict right atrial pressures in patients receiving mechanical ventilation? J Am Soc Echocardiogr. 1992;5: 613-619. 6. Machraoui A, Von Dryander S, Hinrichsen M, et al. Two-dimensional echocardiographic assessment of right cardiac pressure overload in patients with chronic obstructive airway disease. Respiration. 1993;60:65-73. 7. Stein J, Neumann A, Marcus R. Comparison of estimates of right atrial pressure by physical examination and echocardiography in patients with congestive heart failure and reasons for discrepancies. Am J Cardiol. 1997;80:1615-1618. 8. Zolty R. B-natriuretic peptide, a new tool for managing congestive heart failure. Primary Care Case Rev. 2003;6:21-28. 9. ACC/AHA guidelines for the evaluation and management of chronic heart failure in the adult: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (committee to revise the 1995 Guidelines for the Evaluation and Management of Heart Failure). J Am Coll Cardiol. 2001;38:2101-2113.
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