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Optimal shoulder roll height for internal jugular venous cannulation: a study of awake adult volunteers
Journal of Clinical Anesthesia (2012) 24, 179–184
Original contribution
Optimal shoulder roll height for internal jugular venous cannulation: a study of awake adult volunteers☆,☆☆,★ Wen-Kuei Chang MD (Clinical Assistant Professor of Anesthesiology; Division Chief), Yu-Chieh Wang MD (Assistant Professor of Anesthesiology), Chien-Kun Ting MD, PhD (Staff Anesthesiologist), Hung-Wei Cheng MD (Staff Anesthesiologist), Kwok-Hon Chan MD (Associate Professor of Anesthesiology; Chairman), Pin-Tarng Chen MD (Assistant Professor of Anesthesiology)⁎ Department of Anesthesiology, Taipei Veterans General Hospital, Taipei 112, Taiwan, ROC; and Department of Anesthesiology, National Yang-Ming University School of Medicine, Taipei 112, Taiwan, ROC Received 19 August 2010; revised 16 June 2011; accepted 4 July 2011
Keywords: Internal jugular vein; Shoulder roll; Ultrasonography
Abstract Study Objective: To explore the influence of shoulder roll height on internal jugular vein (IJV) diameter and IJV/common carotid artery (CCA) overlap. Design: Cross-sectional study. Setting: University-affiliated hospital. Patients: 40 healthy participants. Measurements: Ultrasonography to measure the effects of using shoulder rolls ranging between 0 and 5 cm high on IJV diameter, CCA diameter, and percentage overlap of the CCA. Main Results: The percentage overlap of CCA decreased for both left (LIJV) and right IJV (RIJV) with the use of higher shoulder rolls. Greater values were seen in depth from skin surface to anterior wall of left IJV in almost all stages, with the exception of Stages 0 and 1 (P b 0.016); and the use of a 5 cm shoulder roll resulted in a significantly decreased anteroposterior (AP) diameter of both RIJVs and LIJVs (both P b 0.008). Conclusions: Shoulder rolls can reduce the overlap between the IJV and CCA, and may be useful in positioning patients for IJV puncture. © 2012 Elsevier Inc. All rights reserved.
☆
Supported by the Anesthesiology Research and Development Foundation, Taipei, Taiwan. Authors' contributions: We declare that all the listed authors have participated actively in the study and all meet the requirements of the authorship. Dr. Pin-Tarng Chen designed the study and wrote the protocol, Dr. Yu-Chieh Wang performed research/study, Dr. Hung-Wei Cheng and Dr. Kwok-Hon Chan managed the literature searches and analyses, Dr. Chien-Kun Ting undertook the statistical analysis, Dr. Wen-Kuei Chang wrote the first draft of the manuscript. ★ Competing interests: The authors declare that they have no competing interests. ⁎ Correspondence and reprint requests: Pin-Tarng Chen, MD, Department of Anesthesiology, Taipei Veterans General Hospital, No. 201, Sec. 2, Shipai Rd., Taipei 112, Taiwan, ROC. Tel.: + (886)-2-28-75-7549; fax: + (886)-2-28-75-1597. E-mail address: [email protected] (P.-T. Chen). ☆☆
0952-8180/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.jclinane.2011.07.001
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1. Introduction Internal jugular vein (IJV) cannulation by percutaneous puncture is commonly performed during major surgery and intensive care. The right IJV (RIJV) is preferred over the left (LIJV) because of its direct route to the superior vena cava, its distance from the pleura, and the absence of the thoracic duct. In the absence of ultrasound guidance, external anatomical landmarks or pulsation of the carotid artery are used to guide IJV cannulation. This approach may be difficult in patients with varied anatomy, especially if the IJV overlaps with the common carotid artery (CCA). Ultrasound guidance does not prevent vascular compression or collapse, which may lead to accidental arterial puncture if the IJV lies anterior to the CCA [1,2]. Successful cannulation is directly correlated with venous distension and minimal CCA overlap [3]. A number of maneuvers have been adopted to increase the IJV diameter and cross-sectional area. These include head rotation [4], head-down tilt [5], Valsalva maneuver [6], humming [7], Trendelenburg tilt [8], abdominal compression [9], and passive leg elevation [10]. Positive end-expiratory pressure increases IJV cross-sectional area [11]. There has been no study of the effect of elevation, and there is scant guidance on how to minimize overlapping of arteries. The traditional method of cannulation is with the patient in a supine position without shoulder elevation; however, studies [12,13] have focused on the use of pillows to help with elevation. We used ultrasonography to measure the effects of shoulder rolls from between 0 and 5 cm high on IJV diameter, CCA diameter, and percentage overlap of the CCA.
2. Materials and methods Forty healthy participants were enrolled in this study; they had not been taking any medications and had no history of prior central venous catheterization or neck surgery. This study was approved by the Institutional Review Board of the Taipei Veterans General Hospital (VGHIRB No: 95-1203A), and written, informed consent was obtained from all participants. A two-dimensional linear array probe (8L-RS; GE Healthcare, London, UK) was used to obtain ultrasound images of both RIJVs and LIJVs and CCAs from awake participants (Vivid e; GE Healthcare). The probe was held perpendicular to the skin over the IJV at the level of the cricoid cartilage in the transverse axis. One investigator obtained all ultrasound images so as to maintain consistency of results. Images were stored on a digitized hard disk for digital computer processing and subsequent analysis by independent investigators. The following sequence was used for each side: Stage 0 = table flat (no tilt), subject supine with head rotated 30° to the contralateral side; Stage T = Trendelenburg tilt and head rotated 30° to the contralateral side; Stage 1 = Trendelenburg
W.-K. Chang et al. tilt and head rotated 30° to the contralateral side with a 1.0 cm shoulder roll; Stage 2 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 2.0 cm shoulder roll; Stage 3 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 3.0 cm shoulder roll; Stage 4 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 4.0 cm shoulder roll; and Stage 5 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 5.0 cm shoulder roll. The following measurements were studied: depth from skin surface to the anterior wall of the IJV, transverse diameter of the IJV, AP diameter of the IJV, and overlap of IJV with CCA (Fig. 1). Percentage overlap was defined as [IJV overlap of CCA/CCA diameter] × 100. Data are expressed as means ± standard deviation. A paired t-test was used to compare measurements at each stage between right and left sides. A P-value b 0.05 was considered statistically significant. Repeated-measures analysis of variance with a post-hoc least squares difference (LSD) method was performed for multiple comparisons between Stage 0 and Stage T, Stage 1 and Stage T, Stage 2 and Stage T, Stage 3 and Stage T, Stage 4 and Stage T, and Stage 5 and Stage T. An adjusted P-value of 0.08 ( = 0.05/6) was considered statistically significant for multiple comparisons.
3. Results Mean age of the participants was 31.6 ± 9.1 years, mean height was 165.5 ± 8.9 cm, mean weight was 61.0 ± 15.1 kg, and mean body mass index was 22.1 ± 3.9 kg/m2 (Table 1). A series of ultrasound images taken from a single representative is shown in Fig. 2. There was an increasing trend noted in the depth from skin surface to the anterior wall of the bilateral IJVs as shoulder roll height increased. Significantly higher values than at Stage T for the depth from skin surface to the anterior wall were seen for the LIJV than the RIJV in all stages except Stage 0 and Stage 1 (Fig. 3A; P b 0.016). Percent overlap decreased for both sides with the use of higher shoulder rolls. The percentage overlap for Stage 3 (3.0 cm shoulder roll) was 34.3 ± 26.8% compared with 55.3 ± 25% at Stage T (Trendelenburg tilt, head rotation, no shoulder roll) in the right IJV. At Stage 5 (5.0 cm shoulder roll) and overlap index was 28.7 ± 28.0% (adjusted P b 0.008). However, use of a shoulder roll did not result in either increased transverse or AP diameter of IJVs. In fact, use of a 5.0 cm pillow resulted in a markedly decreased AP diameter for both RIJVs (8.3 ± 2.4 mm vs 12.3 ± 2.3 mm; P b 0.008) and LIJVs (6.9 ± 2.1 mm vs 8.8 ± 2.4 mm; P b 0.008). There was a decreasing trend for transverse and AP diameters of both IJVs following the use of shoulder rolls of increasing height. No significant changes were noted in the CCA diameter at any stage (Fig. 3).
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Fig. 1 Anatomical view and representative ultrasound image of internal jugular veins (IJVs) and common coronary arteries (CCAs). s1 = depth from skin surface to the anterior wall of IJV, s2 = depth from skin surface to the posterior wall of the IJV, d = transverse diameter of the IJV; d2 = anteroposterior (AP) diameter of the IJV, RCCA = right common carotid artery, LCCA = left common carotid artery, d3 = transverse diameter of the CCA, O = IJV overlap of CCA. Scale bar appears at the right of each image. The depth was 3.0 cm in each image.
4. Discussion Use of a shoulder roll with the subject in the classical position did not result in increased transverse or AP diameter of IJVs, and use of higher shoulder rolls decreased percentage overlap of CCA for both left and right IJVs. We measured depth from skin surface to the anterior wall of the IJV to determine if using a shoulder roll brought the IJV
Table 1 Characteristics of the 40 healthy volunteer participants (N = 40) Age (yrs) Gender (M/F) Height (cm) Weight (kg) BMI (kg/m2) Neck (cm) Thyromental distance (cm) Distance from chin to sternal notch (cm)
31.6 ± 9.1 16/24 165.5 ± 8.9 61.0 ± 15.1 22.1 ± 3.9 35.0 ± 5.1 8.9 ± 1.1 17.6 ± 2.1
BMI = body mass index. Except for gender, data are means ± standard deviation.
closer to the surface, thus rendering it easier to cannulate. However, the shoulder roll instead somewhat increased IJV depth. Our results corroborated the findings Ybarra et al [12], who found that use of a shoulder roll with the head turned contralaterally resulted in a lower transverse diameter of the IJV in healthy children when compared with the Trendelenburg tilt alone (0.47 ± 0.22 vs 0.80 ± 0.27). We found a decreasing trend for transverse and AP diameters of both IJVs following the use of shoulder rolls to increase height. The reduction in IJV diameter with higher shoulder rolls likely was due to extension of the neck musculature and compression of the IJV and surrounding structures [13,14]. Armstrong et al [13] similarly found reductions in IJV diameter size with the use of a bolster under the shoulder. Thus, while certain decreases in CCA overlap were seen from increased hyperextension of the neck and delineation of the IJV with higher shoulder rolls, the reduced IJV diameter size that occurred did not appear to support the superiority of shoulder rolls above a certain height over use of the Trendelenburg tilt alone. The benefits of the Trendelenburg tilt and head rotation are well known. The Trendelenburg tilt increases venous return, in turn increasing the transversal section of the IJV. Reported
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Fig. 2 Serial ultrasound images of bilateral necks. The probe was held perpendicular to the skin over the internal jugular vein (IJV) at the cricoid cartilage level in the transverse axis to obtain the images according to each stage. Stage 0 = table flat (no tilt), subject supine with head rotated 30° to the contralateral side; Stage T = Trendelenburg tilt and head rotated 30° to the contralateral side; Stage 1 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 1.0 cm shoulder roll; Stage 2 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 2.0 cm shoulder roll; Stage 3 = Trendelenburg tilt and head rotated 30° to the contralateral side, with a 3.0 cm shoulder roll; Stage 4 = Trendelenburg tilt and head rotated 30° to the contralateral side, with a 4.0 cm shoulder roll; Stage 5 = Trendelenburg tilt and head rotated 30° to the contralateral side, with a 5.0 cm shoulder roll.
increases in IJV cross-sectional area by Trendelenburg tilt alone range from 22% to 36% without simulated venipuncture [4,7-10,12-15]. Rotation of the head to the contralateral side by 30° to 60° greatly increases the probability of intersecting the IJV; extreme head rotation (70°to 90°) increases the degree of CCA overlap but may also increase the risk of accidental arterial puncture [15,16]. Other maneuvers such as the head-down tilt [5], Valsalva maneuver [6], humming [7], and passive leg elevation [10] have varying degrees of efficacy. There is currently no consensus as to the optimal maneuver or position to facilitate IJV cannulation. The left side of the IJV is smaller than the right side [17,18], a fact that renders the right side more suitable to cannulation. In this study, we showed that in our subject group the left IJV was smaller than the right side, rendering it more difficult to perform left-sided cannulation. However, since the CCA diameter is similar for both sides, equal actual lengths of overlap would result in a greater percent of overlap on the IJV with the left side, thus increasing the possibility of arterial puncture, lower success rate, and higher comorbidity. The actual length of the overlap on the left side was smaller
than on the right side, so, in spite of the smaller AP diameter of the LIJV, its percentage overlap was smaller than that of the RIJV. There could be many reasons for the smaller actual length of overlap on the left side, mostly due to anatomical positioning, as the vessels of the two sides have a different root/branch of origin. The RCCA is a branch of the innominate artery (brachiocephalic trunk) and the RIJV flows into the right innominate vein. The LCCA is a branch of the aortic arch and the RIJV flows into the left innominate vein. However, we can only speculate about the effect of anatomical positioning; from this current study, we were unable to provide direct evidence. There were two reasons that a shoulder roll up to 5 cm was used, rather than continuing with rolls of 6 cm to 10 cm. From other reports, we knew that if the shoulder roll were too high, the IJV would be too flat, rendering it even less suitable for cannulation. Second, high shoulder rolls are physically uncomfortable for patients. Only one ultrasonographic probe position, the central landmark position, was adopted for all patients. Although the real-time, ultrasound-guided cannulation technique has been
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Fig. 3 Comparison of ultrasound measurements of the internal jugular veins (IJVs), common carotid arteries (CCAs), and percent CCA overlap with shoulder rolls of increasing height. A. Depth from skin surface to anterior wall of the IJV. B. Percent overlap. C. Transverse IJV diameter. D. Anteroposterior IJV diameter. E. CCA diameter. Data are means ± SD of right neck and left neck for each stage. ⁎P b 0.05 right vs left sides. †P b 0.008 ( = 0.05/6) Stage 0 vs Stage T, Stage 1 vs Stage T, Stage 2 vs Stage T, Stage 3 vs Stage T, Stage 4 vs Stage T, Stage 5 vs Stage T).
popular, ultrasonography equipment is not always available at certain places or times. In such circumstances, IJV cannulation must be performed using anatomical landmarks, of which the most stable approach is via the central landmark. As we used only the central landmark position, our findings may then serve as a reference for patient positioning, in the absence of ultrasound, as to how to reduce IJV/CCA overlap. While most textbooks and studies in this area suggest that overlap may be reduced by turning the patient's head to the contralateral side, they fail to provide a guideline for
shoulder positioning. We hoped to propose a convenient and feasible approach to minimize the overlap. Undoubtedly, there will be imagery variation when the probe is moved in one direction or another, and a greater variation may arise when the probe is moved toward the clavicle or the head. Our study was limited to healthy, younger adult volunteers of normal weight. The results might not be applicable to older patients, as their anatomy and neck extension ability might be different. We did not evaluate whether the use of a shoulder roll would exhibit similar effects in patients with greater neck sizes or in patients with
184 hemodynamic derangements. We also did not examine the cannulation success rate with the use of shoulder rolls in the classical position. Our findings provided evidence of the effects of shoulder rolls on IJV diameter and percent overlap, and may have future utility in positioning patients for IJV puncture.
Acknowledgments We would like to thank the volunteers for their assistance in data collection. This study was supported by the Anesthesiology Research and Development Foundation, Taipei, Taiwan.
References [1] Turba UC, Uflacker R, Hannegan C, Selby JB. Anatomic relationship of the internal jugular vein and the common carotid artery applied to percutaneous transjugular procedures. Cardiovasc Intervent Radiol 2005;28:303-6. [2] Abboud PA, Kendall JL. Ultrasound guidance for vascular access. Emerg Med Clin North Am 2004;22:749-73. [3] Gordon AC, Saliken JC, Johns D, Owen R, Gray RR. US-guided puncture of the internal jugular vein: complications and anatomic considerations. J Vasc Interv Radiol 1998;9:333-8. [4] Korshin J, Klauber PV, Christensen V, Skovsted P. Percutaneous catheterization of the internal jugular vein. Acta Anaesthesiol Scand Suppl 1978;67:27-33. [5] Schreiber SJ, Lambert UK, Doepp F, Valdueza JM. Effects of prolonged head-down tilt on internal jugular vein cross-sectional area. Br J Anaesth 2002;89:769-71. [6] Beddy P, Geoghegan T, Ramesh N. Valsalva and gravitational variability of the internal jugular vein and common femoral vein: ultrasound assessment. Eur J Radiol 2006;58:307-9.
W.-K. Chang et al. [7] Lewin MR, Stein J, Wang R. Humming is as effective as Valsalva's maneuver and Trendelenburg's position for ultrasonographic visualization of the jugular venous system and common femoral veins. Ann Emerg Med 2007;50:73-7. [8] Mallory DL, Shawker T, Evans RG. Effects of clinical maneuvers on sonographically determined internal jugular vein size during venous cannulation. Crit Care Med 1990;18:1269-73. [9] Verghese ST, Nath A, Zenger D, Patel RI, Kaplan RF, Patel KM. The effects of the simulated Valsalva maneuver, liver compression, and/or Trendelenburg position on the cross-sectional area of the internal jugular vein in infants and young children. Anesth Analg 2002;94:250-4. [10] Kim JT, Kim HS, Lim YJ. The influence of passive leg elevation on the cross-sectional area of the internal jugular vein and the subclavian vein in awake adults. Anaesth Intensive Care 2008;36:65-8. [11] Hollenbeck KJ, Vender Schuur BM, Tulis MR, et al. Effects of positive end-expiratory pressure on internal jugular vein crosssectional area in anesthetized adults. Anesth Analg 2010;110:1669-73. [12] Ybarra LF, Ruiz H, Silva MP, Lederman HM, Schettini ST. Ultrasound evaluations of internal jugular vein punction techniques in children: the easiest method to reach the target area. Pediatr Surg Int 2009;25:99-104. [13] Armstrong PJ, Sutherland R, Scott DH. The effect of position and different manoeuvres on internal jugular vein diameter size. Acta Anaesthesiol Scand 1994;38:229-31. [14] Parry G. Trendelenburg position, head elevation and a midline position optimize right internal jugular vein diameter. Can J Anaesth 2004;51: 379-81. [15] Bellazzini MA, Rankin PM, Gangnon RE, Bjoernsen LP. Ultrasound validation of maneuvers to increase internal jugular vein cross-sectional area and decrease compressibility. Am J Emerg Med 2009;27:454-9. [16] Sulek CA, Gravenstein N, Blackshear RH, Weiss L. Head rotation during internal jugular vein cannulation and the risk of carotid artery puncture. Anesth Analg 1996;82:125-8. [17] Lieberman JA, Williams KA, Rosenberg AL. Optimal head rotation for internal jugular vein cannulation when relying on external landmarks. Anesth Analg 2004;99:982-8. [18] Tartière D, Seguin P, Juhel C, Laviolle B, Mallédant Y. Estimation of the diameter and cross-sectional area of the internal jugular veins in adult patients. Crit Care 2009;13:R197.
Original contribution
Optimal shoulder roll height for internal jugular venous cannulation: a study of awake adult volunteers☆,☆☆,★ Wen-Kuei Chang MD (Clinical Assistant Professor of Anesthesiology; Division Chief), Yu-Chieh Wang MD (Assistant Professor of Anesthesiology), Chien-Kun Ting MD, PhD (Staff Anesthesiologist), Hung-Wei Cheng MD (Staff Anesthesiologist), Kwok-Hon Chan MD (Associate Professor of Anesthesiology; Chairman), Pin-Tarng Chen MD (Assistant Professor of Anesthesiology)⁎ Department of Anesthesiology, Taipei Veterans General Hospital, Taipei 112, Taiwan, ROC; and Department of Anesthesiology, National Yang-Ming University School of Medicine, Taipei 112, Taiwan, ROC Received 19 August 2010; revised 16 June 2011; accepted 4 July 2011
Keywords: Internal jugular vein; Shoulder roll; Ultrasonography
Abstract Study Objective: To explore the influence of shoulder roll height on internal jugular vein (IJV) diameter and IJV/common carotid artery (CCA) overlap. Design: Cross-sectional study. Setting: University-affiliated hospital. Patients: 40 healthy participants. Measurements: Ultrasonography to measure the effects of using shoulder rolls ranging between 0 and 5 cm high on IJV diameter, CCA diameter, and percentage overlap of the CCA. Main Results: The percentage overlap of CCA decreased for both left (LIJV) and right IJV (RIJV) with the use of higher shoulder rolls. Greater values were seen in depth from skin surface to anterior wall of left IJV in almost all stages, with the exception of Stages 0 and 1 (P b 0.016); and the use of a 5 cm shoulder roll resulted in a significantly decreased anteroposterior (AP) diameter of both RIJVs and LIJVs (both P b 0.008). Conclusions: Shoulder rolls can reduce the overlap between the IJV and CCA, and may be useful in positioning patients for IJV puncture. © 2012 Elsevier Inc. All rights reserved.
☆
Supported by the Anesthesiology Research and Development Foundation, Taipei, Taiwan. Authors' contributions: We declare that all the listed authors have participated actively in the study and all meet the requirements of the authorship. Dr. Pin-Tarng Chen designed the study and wrote the protocol, Dr. Yu-Chieh Wang performed research/study, Dr. Hung-Wei Cheng and Dr. Kwok-Hon Chan managed the literature searches and analyses, Dr. Chien-Kun Ting undertook the statistical analysis, Dr. Wen-Kuei Chang wrote the first draft of the manuscript. ★ Competing interests: The authors declare that they have no competing interests. ⁎ Correspondence and reprint requests: Pin-Tarng Chen, MD, Department of Anesthesiology, Taipei Veterans General Hospital, No. 201, Sec. 2, Shipai Rd., Taipei 112, Taiwan, ROC. Tel.: + (886)-2-28-75-7549; fax: + (886)-2-28-75-1597. E-mail address: [email protected] (P.-T. Chen). ☆☆
0952-8180/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.jclinane.2011.07.001
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1. Introduction Internal jugular vein (IJV) cannulation by percutaneous puncture is commonly performed during major surgery and intensive care. The right IJV (RIJV) is preferred over the left (LIJV) because of its direct route to the superior vena cava, its distance from the pleura, and the absence of the thoracic duct. In the absence of ultrasound guidance, external anatomical landmarks or pulsation of the carotid artery are used to guide IJV cannulation. This approach may be difficult in patients with varied anatomy, especially if the IJV overlaps with the common carotid artery (CCA). Ultrasound guidance does not prevent vascular compression or collapse, which may lead to accidental arterial puncture if the IJV lies anterior to the CCA [1,2]. Successful cannulation is directly correlated with venous distension and minimal CCA overlap [3]. A number of maneuvers have been adopted to increase the IJV diameter and cross-sectional area. These include head rotation [4], head-down tilt [5], Valsalva maneuver [6], humming [7], Trendelenburg tilt [8], abdominal compression [9], and passive leg elevation [10]. Positive end-expiratory pressure increases IJV cross-sectional area [11]. There has been no study of the effect of elevation, and there is scant guidance on how to minimize overlapping of arteries. The traditional method of cannulation is with the patient in a supine position without shoulder elevation; however, studies [12,13] have focused on the use of pillows to help with elevation. We used ultrasonography to measure the effects of shoulder rolls from between 0 and 5 cm high on IJV diameter, CCA diameter, and percentage overlap of the CCA.
2. Materials and methods Forty healthy participants were enrolled in this study; they had not been taking any medications and had no history of prior central venous catheterization or neck surgery. This study was approved by the Institutional Review Board of the Taipei Veterans General Hospital (VGHIRB No: 95-1203A), and written, informed consent was obtained from all participants. A two-dimensional linear array probe (8L-RS; GE Healthcare, London, UK) was used to obtain ultrasound images of both RIJVs and LIJVs and CCAs from awake participants (Vivid e; GE Healthcare). The probe was held perpendicular to the skin over the IJV at the level of the cricoid cartilage in the transverse axis. One investigator obtained all ultrasound images so as to maintain consistency of results. Images were stored on a digitized hard disk for digital computer processing and subsequent analysis by independent investigators. The following sequence was used for each side: Stage 0 = table flat (no tilt), subject supine with head rotated 30° to the contralateral side; Stage T = Trendelenburg tilt and head rotated 30° to the contralateral side; Stage 1 = Trendelenburg
W.-K. Chang et al. tilt and head rotated 30° to the contralateral side with a 1.0 cm shoulder roll; Stage 2 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 2.0 cm shoulder roll; Stage 3 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 3.0 cm shoulder roll; Stage 4 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 4.0 cm shoulder roll; and Stage 5 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 5.0 cm shoulder roll. The following measurements were studied: depth from skin surface to the anterior wall of the IJV, transverse diameter of the IJV, AP diameter of the IJV, and overlap of IJV with CCA (Fig. 1). Percentage overlap was defined as [IJV overlap of CCA/CCA diameter] × 100. Data are expressed as means ± standard deviation. A paired t-test was used to compare measurements at each stage between right and left sides. A P-value b 0.05 was considered statistically significant. Repeated-measures analysis of variance with a post-hoc least squares difference (LSD) method was performed for multiple comparisons between Stage 0 and Stage T, Stage 1 and Stage T, Stage 2 and Stage T, Stage 3 and Stage T, Stage 4 and Stage T, and Stage 5 and Stage T. An adjusted P-value of 0.08 ( = 0.05/6) was considered statistically significant for multiple comparisons.
3. Results Mean age of the participants was 31.6 ± 9.1 years, mean height was 165.5 ± 8.9 cm, mean weight was 61.0 ± 15.1 kg, and mean body mass index was 22.1 ± 3.9 kg/m2 (Table 1). A series of ultrasound images taken from a single representative is shown in Fig. 2. There was an increasing trend noted in the depth from skin surface to the anterior wall of the bilateral IJVs as shoulder roll height increased. Significantly higher values than at Stage T for the depth from skin surface to the anterior wall were seen for the LIJV than the RIJV in all stages except Stage 0 and Stage 1 (Fig. 3A; P b 0.016). Percent overlap decreased for both sides with the use of higher shoulder rolls. The percentage overlap for Stage 3 (3.0 cm shoulder roll) was 34.3 ± 26.8% compared with 55.3 ± 25% at Stage T (Trendelenburg tilt, head rotation, no shoulder roll) in the right IJV. At Stage 5 (5.0 cm shoulder roll) and overlap index was 28.7 ± 28.0% (adjusted P b 0.008). However, use of a shoulder roll did not result in either increased transverse or AP diameter of IJVs. In fact, use of a 5.0 cm pillow resulted in a markedly decreased AP diameter for both RIJVs (8.3 ± 2.4 mm vs 12.3 ± 2.3 mm; P b 0.008) and LIJVs (6.9 ± 2.1 mm vs 8.8 ± 2.4 mm; P b 0.008). There was a decreasing trend for transverse and AP diameters of both IJVs following the use of shoulder rolls of increasing height. No significant changes were noted in the CCA diameter at any stage (Fig. 3).
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Fig. 1 Anatomical view and representative ultrasound image of internal jugular veins (IJVs) and common coronary arteries (CCAs). s1 = depth from skin surface to the anterior wall of IJV, s2 = depth from skin surface to the posterior wall of the IJV, d = transverse diameter of the IJV; d2 = anteroposterior (AP) diameter of the IJV, RCCA = right common carotid artery, LCCA = left common carotid artery, d3 = transverse diameter of the CCA, O = IJV overlap of CCA. Scale bar appears at the right of each image. The depth was 3.0 cm in each image.
4. Discussion Use of a shoulder roll with the subject in the classical position did not result in increased transverse or AP diameter of IJVs, and use of higher shoulder rolls decreased percentage overlap of CCA for both left and right IJVs. We measured depth from skin surface to the anterior wall of the IJV to determine if using a shoulder roll brought the IJV
Table 1 Characteristics of the 40 healthy volunteer participants (N = 40) Age (yrs) Gender (M/F) Height (cm) Weight (kg) BMI (kg/m2) Neck (cm) Thyromental distance (cm) Distance from chin to sternal notch (cm)
31.6 ± 9.1 16/24 165.5 ± 8.9 61.0 ± 15.1 22.1 ± 3.9 35.0 ± 5.1 8.9 ± 1.1 17.6 ± 2.1
BMI = body mass index. Except for gender, data are means ± standard deviation.
closer to the surface, thus rendering it easier to cannulate. However, the shoulder roll instead somewhat increased IJV depth. Our results corroborated the findings Ybarra et al [12], who found that use of a shoulder roll with the head turned contralaterally resulted in a lower transverse diameter of the IJV in healthy children when compared with the Trendelenburg tilt alone (0.47 ± 0.22 vs 0.80 ± 0.27). We found a decreasing trend for transverse and AP diameters of both IJVs following the use of shoulder rolls to increase height. The reduction in IJV diameter with higher shoulder rolls likely was due to extension of the neck musculature and compression of the IJV and surrounding structures [13,14]. Armstrong et al [13] similarly found reductions in IJV diameter size with the use of a bolster under the shoulder. Thus, while certain decreases in CCA overlap were seen from increased hyperextension of the neck and delineation of the IJV with higher shoulder rolls, the reduced IJV diameter size that occurred did not appear to support the superiority of shoulder rolls above a certain height over use of the Trendelenburg tilt alone. The benefits of the Trendelenburg tilt and head rotation are well known. The Trendelenburg tilt increases venous return, in turn increasing the transversal section of the IJV. Reported
182
W.-K. Chang et al.
Fig. 2 Serial ultrasound images of bilateral necks. The probe was held perpendicular to the skin over the internal jugular vein (IJV) at the cricoid cartilage level in the transverse axis to obtain the images according to each stage. Stage 0 = table flat (no tilt), subject supine with head rotated 30° to the contralateral side; Stage T = Trendelenburg tilt and head rotated 30° to the contralateral side; Stage 1 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 1.0 cm shoulder roll; Stage 2 = Trendelenburg tilt and head rotated 30° to the contralateral side with a 2.0 cm shoulder roll; Stage 3 = Trendelenburg tilt and head rotated 30° to the contralateral side, with a 3.0 cm shoulder roll; Stage 4 = Trendelenburg tilt and head rotated 30° to the contralateral side, with a 4.0 cm shoulder roll; Stage 5 = Trendelenburg tilt and head rotated 30° to the contralateral side, with a 5.0 cm shoulder roll.
increases in IJV cross-sectional area by Trendelenburg tilt alone range from 22% to 36% without simulated venipuncture [4,7-10,12-15]. Rotation of the head to the contralateral side by 30° to 60° greatly increases the probability of intersecting the IJV; extreme head rotation (70°to 90°) increases the degree of CCA overlap but may also increase the risk of accidental arterial puncture [15,16]. Other maneuvers such as the head-down tilt [5], Valsalva maneuver [6], humming [7], and passive leg elevation [10] have varying degrees of efficacy. There is currently no consensus as to the optimal maneuver or position to facilitate IJV cannulation. The left side of the IJV is smaller than the right side [17,18], a fact that renders the right side more suitable to cannulation. In this study, we showed that in our subject group the left IJV was smaller than the right side, rendering it more difficult to perform left-sided cannulation. However, since the CCA diameter is similar for both sides, equal actual lengths of overlap would result in a greater percent of overlap on the IJV with the left side, thus increasing the possibility of arterial puncture, lower success rate, and higher comorbidity. The actual length of the overlap on the left side was smaller
than on the right side, so, in spite of the smaller AP diameter of the LIJV, its percentage overlap was smaller than that of the RIJV. There could be many reasons for the smaller actual length of overlap on the left side, mostly due to anatomical positioning, as the vessels of the two sides have a different root/branch of origin. The RCCA is a branch of the innominate artery (brachiocephalic trunk) and the RIJV flows into the right innominate vein. The LCCA is a branch of the aortic arch and the RIJV flows into the left innominate vein. However, we can only speculate about the effect of anatomical positioning; from this current study, we were unable to provide direct evidence. There were two reasons that a shoulder roll up to 5 cm was used, rather than continuing with rolls of 6 cm to 10 cm. From other reports, we knew that if the shoulder roll were too high, the IJV would be too flat, rendering it even less suitable for cannulation. Second, high shoulder rolls are physically uncomfortable for patients. Only one ultrasonographic probe position, the central landmark position, was adopted for all patients. Although the real-time, ultrasound-guided cannulation technique has been
Shoulder roll eases jugular venous cannulation
183
Fig. 3 Comparison of ultrasound measurements of the internal jugular veins (IJVs), common carotid arteries (CCAs), and percent CCA overlap with shoulder rolls of increasing height. A. Depth from skin surface to anterior wall of the IJV. B. Percent overlap. C. Transverse IJV diameter. D. Anteroposterior IJV diameter. E. CCA diameter. Data are means ± SD of right neck and left neck for each stage. ⁎P b 0.05 right vs left sides. †P b 0.008 ( = 0.05/6) Stage 0 vs Stage T, Stage 1 vs Stage T, Stage 2 vs Stage T, Stage 3 vs Stage T, Stage 4 vs Stage T, Stage 5 vs Stage T).
popular, ultrasonography equipment is not always available at certain places or times. In such circumstances, IJV cannulation must be performed using anatomical landmarks, of which the most stable approach is via the central landmark. As we used only the central landmark position, our findings may then serve as a reference for patient positioning, in the absence of ultrasound, as to how to reduce IJV/CCA overlap. While most textbooks and studies in this area suggest that overlap may be reduced by turning the patient's head to the contralateral side, they fail to provide a guideline for
shoulder positioning. We hoped to propose a convenient and feasible approach to minimize the overlap. Undoubtedly, there will be imagery variation when the probe is moved in one direction or another, and a greater variation may arise when the probe is moved toward the clavicle or the head. Our study was limited to healthy, younger adult volunteers of normal weight. The results might not be applicable to older patients, as their anatomy and neck extension ability might be different. We did not evaluate whether the use of a shoulder roll would exhibit similar effects in patients with greater neck sizes or in patients with
184 hemodynamic derangements. We also did not examine the cannulation success rate with the use of shoulder rolls in the classical position. Our findings provided evidence of the effects of shoulder rolls on IJV diameter and percent overlap, and may have future utility in positioning patients for IJV puncture.
Acknowledgments We would like to thank the volunteers for their assistance in data collection. This study was supported by the Anesthesiology Research and Development Foundation, Taipei, Taiwan.
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