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Is a Neutral Head Position Safer than 45-Degree Neck Rotation During Ultrasound-Guided Internal Jugular Vein Cannulation? Results of a Randomized Controlled Clinical Trial

Lamperti, Massimo MD*; Subert, Matteo MD*; Cortellazzi, Paolo MD*; Vailati, Davide MD*; Borrelli, Paola PhD; Montomoli, Cristina PhD; D'Onofrio, Giovanni MD*; Caldiroli, Dario MD*

doi: 10.1213/ANE.0b013e3182459917
Patient Safety: Research Reports
Chinese Language Editions
Continuing Medical Education

BACKGROUND: The optimal degree of neck rotation during internal jugular vein (IJV) cannulation remains undetermined because previous studies suggested using sonography, but without puncturing the vein. We assessed whether a neutral position (NP) of the head (0 degrees) during ultrasound-guided cannulation of the IJV was safer than rotating the neck to 45 degrees head turned. The effect of these 2 positions during ultrasound-guided cannulation on major complications was the primary outcome. Overall complications, venous access time, and perception of difficulty during the procedure were also evaluated.

METHODS: A prospective, randomized, controlled, nonblinded study was conducted in a tertiary neurosurgical hospital. Patients undergoing major elective neurosurgical procedures requiring a central venous line were randomly allocated to 2 groups; ultrasound-guided cannulation of the IJV was then performed using an out-of-plane orientation.

RESULTS: One thousand four hundred twenty-four patients were evaluated, but 92 were excluded; 670 were allocated to the head turned group and 662 to the NP group. Cannulation was 100% successful. Demographic data were similar in the 2 groups except for IJV positions. There were only 10 major complications: 6 in the 0-degree NP group and 4 in the 45-degree head turned group. The frequency of these complications was not different between the 2 groups. The overall complication rate was 13%, and was higher in women, in patients with ASA physical status ≥II, and in patients with a smaller diameter vein, or when the vein was located deeper and lateral or in the anterolateral position. An increased venous access time was associated with an increased rate of overall complications. The perception of difficulty performing the procedure with the head placed in the 2 positions was not statistically different in either group.

CONCLUSION: A head NP was as safe as a 45-degree neck rotation during ultrasound-guided IJV cannulation with regard to both major and minor complications, and venous access time was similar. Ultrasound guidance helps determine optimal head rotation for IJV cannulation.

Published ahead of print January 17, 2012 Supplemental Digital Content is available in the text.

From the *Department of Neuroanesthesia, Neurological Institute Besta, Milan; and Department of Applied Sciences Medical Statistics and Epidemiology, Universitá di Pavia, Pavia, Italy.

The authors declare no conflicts of interest.

This report was previously presented, in part, at the ASA meeting, 2009.

Reprints will not be available from the authors.

Address correspondence to Massimo Lamperti, MD, Neurological Institute Besta, Via Celoria, 11 20136 Milan, Italy. Address e-mail to doclampmd@gmail.com.

Accepted December 1, 2011

Published ahead of print January 17, 2012

Ultrasound-guided central venous cannulation of the internal jugular vein (IJV) is considered in guidelines1,2 as the method of choice in both elective and emergency settings, in adult and pediatric patients.38 Despite the literature and recommendations, the use of skin surface (anatomical) landmarks for IJV cannulation still prevails in clinical practice,9 and ultrasound guidance is used as a rescue technique in difficult cases, or by novices during central venous cannulation.10

Ultrasound guidance has been shown to significantly increase the efficacy of this procedure in terms of success and access time,17 and in reducing major complications, mainly carotid artery (CA) puncture, pneumothorax, and hemothorax. Such complications are not uncommon when the localization of the vein is based on anatomical landmarks or when a low-lateral approach is used.11,12 Such techniques have a reported incidence of major complications reaching 18%,6,7,13,14 depending on the experience of the operators and on the position of the CA with respect to the IJV. Although associated with a lower incidence, major complications such as arterial cannulation15 have been reported even when ultrasound guidance with a short-axis approach is used, or in young patients and children in whom the vein is easily collapsible.1619

Surface anatomical landmarks have traditionally been used to identify the location of the neck blood vessels for IJV cannulation.20,21 According to the majority of landmark-guided techniques, the head should be turned away from the side of the neck being cannulated, but the degree of rotation is seldom specified.13,17,20,21 Neck rotation can increase the visibility of anatomical landmarks, but it also changes the position of the IJV with respect to the CA22; when the head is in midline position, the IJV is posterior to the CA, and increased neck rotation makes the CA overlap the IJV,22,23 increasing the risk of CA puncture. When relying on external landmarks,24 the optimal degree of neck rotation normally should be <45 degrees; in patients with a large body mass index (BMI), optimal landmark visibility may be obtained at no more than 30-degree rotation, whereas in patients with a small BMI, the preferable degree of neck rotation is closer to 60 degrees. In infants,25 it has been demonstrated that a 0-degree position of the neck produces a reduced overlap between the IJV and CA. These recommendations can be applied to patients whose neck cannot (or should not) be rotated (e.g., head trauma, previous cervical fusion), and to patients with difficult/altered external landmarks (because of obesity or presence of laryngeal airway mask,26 or in burn patients).

To our knowledge, the optimal degree of neck rotation during ultrasound-guided IJV puncture remains undetermined, because previous studies only reported the position of the IJV based on ultrasound scanning in different neck rotations without performing a venous puncture.2326 The purpose of this study was to compare 2 levels of neck rotation during IJV cannulation: 0-degree position (or neutral position [NP]), which should be used in some patients in whom neck rotation is undesirable, and in which the overlap between the IJV and the CA is minimized; and 45-degree (or head turned [HT]) position, which is frequently used with a surface anatomical landmark and with ultrasound-guided techniques.22,28 We first investigated whether neck rotation had any effect on the incidence of major complications. Our secondary aims included determination of whether (1) neck rotation would influence overall complications; (2) venous access time would be different when the neck was positioned at 0 degrees or 45 degrees; and (3) whether neck rotation would affect the operator's perception of technical difficulty in performing the cannulation.

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METHODS

Patients

Institutional Ethics Committee of Neurological Institute Carlo Besta (Milan, Italy) approved the study, and written informed consent was obtained from patients or, when this was not possible, from surrogate decision-makers. The study was conducted in a tertiary neurosurgical center between June 2007 and September 2010. Consecutive patients undergoing major neurosurgical procedures with indications for central venous catheter placement were considered for study inclusion. Indications for inserting a central venous catheter included measurement of central venous pressure, absence of peripheral veins, need for administration of vasoactive/inotropic drugs, and need for administration of hypertonic solutions during or after surgery. As indicated in the flow chart (Fig. 1), exclusion criteria included consent refusal, age <12 years, and coagulopathy.29

Figure 1

Figure 1

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Experimental Protocol

The institutional epidemiologic center performed a simple random patient assignment based on a computer-generated randomization list to 1 of 2 treatment groups (NP or HT). Investigators received an opaque envelope containing the randomization schedule. Given the nature of the procedure, effective blinding of the operators to the patients' head position (NP or HT) was not attempted.

Venous cannulations were performed using the Seldinger technique by 6 anesthesiologists who had extensive experience with the ultrasound-guided technique for IJV cannulation: they previously attended a technical course on ultrasound, and then successfully performed 25 proctored ultrasound-guided IJV cannulations. The 0-degree neck rotation position was defined as having the subject's sagittal plane perpendicular to the floor. We used a leveled protractor to align the sagittal plane to the desired angle. The head and neck were then kept in position by using foam pillows. Throughout the procedure, patients were receiving general anesthesia and mechanical ventilation without positive end-expiratory pressure.30 Patients were placed in the supine horizontal position, and no Trendelenburg was used to facilitate filling of the IJV, because all patients had an increased risk of developing intracranial hypertension. Ultrasound imaging was performed with a SonoSite (Bothell, WA) Titan system equipped with an L25 probe (10–5 MHz, 25-mm broadband linear array). Catheterization was guided by real-time, 2-dimensional images obtained by placing the transducer over the groove between the sternal and clavicular heads of the sternocleidomastoid muscle, aligned parallel to the clavicle. A short-axis ultrasound image was obtained, and an out-of-plane orientation was used with continuous visualization of the needle tip by tilting the ultrasound probe during needle advancement into the vein. The dominant IJV (the side with the vein having the higher cross-sectional diameter) was usually preferred31,32 to maintain a good venous drainage from the brain. Venous access was attained with an 18-gauge needle and confirmed by mechanical transduction (i.e., blood aspiration via the syringe) and with ultrasound needle tip visualization inside the IJV.

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Data Acquisition

Age, sex, ASA physical status (dichotomized as I = normal, and >I = mild or systemic disease), and BMI (dichotomized as <30 kg/m2 = normal, and ≥30 kg/m2 = obese) were recorded at the time of randomization. The following data were also recorded: cross-sectional diameter and depth of the IJV (distance from skin to anterior wall of the IJV); relative position of the IJV with respect to the CA during cannulation, defined as anterior, posterior, anterolateral, or lateral32; side of the dominant IJV; and side of neck where cannulation was performed.

Major mechanical complications were defined as CA puncture, pneumothorax, hemothorax, and neck hematoma.16 Presence of pneumothorax was excluded with a postprocedural pleural ultrasound examination,3335 and if pleural sliding was absent, with a chest radiograph; absence of hemothorax was excluded with a postoperative chest radiograph, and an ultrasound examination of the neck was performed to exclude the presence of hematoma if multiple needle attempts were performed, or when inadvertent carotid puncture occurred. Minor complications were defined as multiple skin punctures, multiple vein punctures, and difficult insertion of the guidewire.6 The occurrence of complications during the procedure and during the first 24 postoperative hours was monitored by an anesthesiologist different from the one performing the cannulation. This anesthesiologist also measured the required venous access time, defined as the time interval (in minutes) between ultrasound visualization of the IJV and aspiration of venous blood via the catheter.

At the end of the procedure, the operator was asked to define his/her perception of difficulty (dichotomized as easy or difficult) when performing the procedure. This subjective assessment could include the difficulty related to neck rotation, which could create an overlapping of the vessels, or the difficulty encountered performing the procedure.

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Statistical Analysis

To calculate the sample size of our study, we referred to the CA puncture incidence in our previous study, in which major complications during ultrasound-guided IJV cannulation were defined as CA puncture, and to a previous study24 in which the incidence of inadvertent CA puncture due to an anterior IJV location was almost 4 times higher. Based on 90% power in detecting a reduction of CA puncture from 2.8% to 0.5% (α = 0.05, two sided), 1424 patients were required. Mean ± SD and percentages were used as descriptive statistics for demographic and ultrasound features. Univariate comparisons for categorical data were made between groups using χ2 test or Fisher exact test (for small sample-sized groups) and Student 2-sided t test with unequal variances or Wilcoxon rank sum test (for non-normality data) for continuous variables. Normality distribution was assessed using the Shapiro-Wilk test. Crude odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were also computed.36 Statistical significance was defined at P < 0.05 level.

A logistic regression was performed to evaluate the effect of demographic and ultrasound characteristics (neck rotation, sex, position of the IJV, ASA physical status, BMI, age, and IJV diameter and depth) in the presence of major and overall complications. Pearson correlation coefficients between IJV diameter, depth, and venous access time were calculated. The goodness-of-fit model was assessed using the Hosmer-Lemeshow test. All analyses were conducted using STATA/SE for Windows, version 10 (StataCorp LP, College Station, TX).

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RESULTS

A total of 1424 patients were considered for inclusion in the study, and 92 of them met at least 1 exclusion criterion (Fig. 1). Randomization and patient data acquisitions were performed for 1332 patients. This provided a power of 87%. Demographic and ultrasound characteristics of the 2 groups are summarized in Tables 1 and 2. Both groups were homogeneous for all characteristics except for the position of the IJV, which was statistically significant (P < 0.0001). Cannulation of the IJV was always successful. Perception of difficulty during IJV cannulation among anesthesiologists (9% in NP vs 11% in HT patients) was not statistically significantly different between the 2 groups (P = 0.19). There was no difference in the frequency of complications between the NP and HT groups.

Table 1

Table 1

Table 2

Table 2

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Primary Outcome

Major complications were recorded in 10 patients: 6 (0.9%) in the NP group and 4 (0.6%) in the HT group; the only major complication recorded was CA puncture. Univariate comparisons did not reveal any difference in terms of major complications between groups or for other characteristics. For this reason, a logistic regression analysis was not performed on major complications as an outcome variable.

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Secondary Outcomes

Overall, secondary complications occurred in 173 patients (13%): 88 complications in NP patients (13.2%), and 85 complications in HT patients (12.6%) (χ2 = 0.10, df = 1, P = 0.74). We found statistically significant differences between overall complications and patient sex, position of the IJV, ASA physical status, BMI, IJV cross-sectional diameter, IJV depth, and venous access time (Table 3). Table 4 shows the distribution of minor complications in the 2 groups. There were no statistically significant differences between groups.

Table 3

Table 3

Table 4

Table 4

Table 5 shows the results of crude and adjusted ORs for overall complications. The logistic regression analysis included, as independent variables, head rotation, sex, position of the IJV, ASA physical status, BMI, age, and IJV diameter and depth, and was adjusted for quarter of the year and by providers. Venous access time was not included in the model, because there was a significant correlation between it and IJV cross-sectional diameter and IJV depth.

Table 5

Table 5

The risk of overall complications increased in female patients (OR 2.31, P < 0.0001, 95% CI 1.61–3.13), increased with ASA physical status ≥II (OR 1.64, P = 0.006, 95% CI 1.15–2.34), and with BMI ≥30 kg/m2 (OR 3.42, P < 0.0001, 95% CI 2.39–4.89). The risk decreased for any unit reduction of IJV diameter (OR 0.84, P < 0.0001, 95% CI 0.77–0.92), increased for any millimeter of IJV depth (OR 1.13, P < 0.0001, 95% CI 1.08–1.18), and was reduced when the IJV was anterior to the vein (OR 0.26, P < 0.0001, 95% CI 0.15–0.44).

The Hosmer-Lemeshow goodness-of-fit test indicated that the model described the data appropriately (χ2 [1316] = 1370.79, P = 0.14).

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DISCUSSION

The main aim of our study was to determine whether neck rotation during ultrasound-guided IJV cannulation would impact the incidence of complications and affect venous cannulation time. This could have a practical clinical impact when neck rotation must be avoided, such as with head trauma patients with neck collars, or in patients with a previous cervical fusion. Based on our results, the incidence of major complications was similar in the 2 neck positions, and did not affect overall complication rate, venous access time, or the perceived difficulty in performing the procedure.

In our experience, IJV access is considered safe in neurosurgical patients, and our group has demonstrated that IJV cannulation with a central venous catheter did not alter cerebral venous outflow in patients with cerebral hypertension.37

Among major complications during IJV cannulation, CA puncture is considered one of the most severe. It has been reported to be relatively common,19 and to cause neck hematoma leading to airway obstruction, or to stroke in the case of CA dissection.15,16 A low (caudad) approach to the IJV has been advocated to insert the indwelling catheter in the larger cross-sectional diameter of the vein, but given its proximity to the pleura and the subclavian artery, this could also cause pneumothorax and hemothorax.32 Our low incidence of major complications (0.75%) is probably attributable to the significant experience of the operators, and inadvertent CA punctures only occurred in the first part of the study (during the first 368 patients).

Some authors have attempted to define the optimal neck rotation during IJV cannulation, both in adults and children,2426,3638 and have demonstrated a reduced overlap of the CA and IJV when the neck was positioned at 0 degrees. Similarly, they reported a larger diameter of the IJV at 45-degree neck rotation. However, these studies used ultrasound guidance for IJV identification and location during head rotation, but did not actually cannulate the vein. A recent ultrasonographic study37 demonstrated that ultrasound images frequently used for IJV access usually depict the vein as being posterior to the CA and only to a minor extent, in the lateral position; our study confirms these findings. To avoid accidental CA puncture during vein puncture, these authors38 suggest determining the ideal puncture site and acquiring images of the neck vessels along their entire course. Our study has shown a significantly reduced overlap between the IJV and CA at 0 degrees, with significantly fewer anterior IJVs in this position, and similar IJV cross-sectional diameters and distance from skin to the vein in the 2 neck rotations, even if these differences in IJV position did not influence our outcomes.

The out-of-plane approach used in our study has recently been criticized, and a long-axis approach with in-plane venipuncture has been suggested to increase safety and efficacy.15,40,41 However, the results of these studies are limited to application to inanimate (manikin) models and cannot be applied to all patients (obese, infants) because it is impossible to place the ultrasound probe longitudinally. Our choice of using a short-axis visualization with out-of-plane venipuncture was based on a previous study28 that revealed that this approach is safe, widely used,18 and allows much faster vascular access than using the long axis.

Overall complications were similar in both groups. The risk of developing a complication is higher in females and in patients with ASA physical status ≥II, and when the IJV had a smaller diameter, it was deeper in the neck, in obese patients, and when it was lateral and anterolateral to the vein. We cannot explain the reason for a higher occurrence of overall complications in lateral IJVs even if this variable is related only to general complications such as multiple skin or vein puncture and not to major complications such as CA puncture. Given those variables, an obese, ASA physical status ≥II, female patient with a lateral or anterolateral IJV had a higher risk of overall complications than an average population patient.

Neck rotation had no effect on vascular access time. The median access time (4.4 minutes) was, however, longer compared with other studies8; this could be explained by the fact that we considered the total time required for performing the procedure (minutes) and not only the time required for the vein puncture (seconds). The decision to measure the entire time required for the procedure was made to demonstrate that, even when using the ultrasound technique with a sterile maneuver, access time is short and comparable to the landmark technique. Access time was significantly related to overall complications, because in every patient in whom a complication occurred, the procedure took longer.

Even if neck rotation could give more room to fit in the ultrasound transducer and the syringe, our data demonstrate that the perception of difficulty by the provider in performing the procedure in a fixed position was similar in the 2 groups.

The present study has some limitations that must be considered: (1) given the nature of the procedure, it was not possible to blind the operator and observer to the degree of neck rotation; (2) all procedures were elective, and there were no patients with head or neck trauma, and no pediatric patients; (3) the performing physicians were from the same department and were experienced with the ultrasound technique; and (4) the rating of difficulty in performing the procedure was subjective.

The effect of neck rotation on vessel placement is variable among patients, and it is unlikely that standardizing neck rotation would be beneficial in all patients.

The main reason for using a 45-degree rotation of the head during IJV cannulation is to maximize the visibility of anatomical landmarks. Ultrasound is very helpful when the alignment of the IJV and CA is such that neck rotation may be needed to optimize access and reduce complications. Standardizing the head position to a neutral position and neck rotation at 45 degrees created some difficulties for our operators, because at 45 degrees, the IJV could overlap the CA creating the risk of inadvertent needle insertion through the posterior wall of the vein and into the CA. When the head was in the neutral position, the operator had to keep his/her hand and the needle in a more lateral position than usual, on a more curved surface, and not always horizontal, to maintain the right straight line toward the IJV, perpendicular to the skin.

Based on our results, when neck rotation is not possible, as is the case with head and neck trauma patients, the IJV can easily be cannulated using ultrasound guidance with similar complications and access time as a normal cannulation when neck rotation is possible. Further studies are needed to confirm whether this conclusion is generally valid in an emergency setting, when an in-plane ultrasound approach is used, and when less-skilled operators perform this procedure.

Our study demonstrated that using ultrasound guidance, the incidence of major complications with both head positions is lower than when using a landmark technique. Furthermore, we noted that after performing approximately 25 procedures, our incidence of procedure-related complications became zero.

In conclusion, our study demonstrates that ultrasound-guided IJV cannulation with the neck placed in the NP (0-degree rotation) is as safe as IJV cannulation with the neck turned to 45 degrees; this technique, however, requires training. Ultrasound guidance helps determine optimal head rotation for IJV cannulation.

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DISCLOSURES

Name: Massimo Lamperti, MD.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Massimo Lamperti has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.

Name: Matteo Subert, MD.

Contribution: This author helped design the study, conduct the study, and write the manuscript.

Attestation: Matteo Subert has seen the original study data and approved the final manuscript.

Name: Paolo Cortellazzi, MD.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Paolo Cortellazzi has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Davide Vailati, MD.

Contribution: This author helped design the study, conduct the study, and write the manuscript.

Attestation: Davide Vailati has seen the original study data and approved the final manuscript.

Name: Paola Borrelli, PhD.

Contribution: This author helped analyze the data and write the manuscript.

Attestation: Paola Borrelli has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Cristina Montomoli, Professor.

Contribution: This author helped analyze the data and write the manuscript.

Attestation: Cristina Montomoli has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Giovanni D'Onofrio, MD.

Contribution: This author helped design the study and conduct the study.

Attestation: Giovanni D'Onofrio has seen the original study data and approved the final manuscript.

Name: Dario Caldiroli, MD.

Contribution: This author helped design the study and conduct the study.

Attestation: Dario Caldiroli has seen the original study data and approved the final manuscript.

This manuscript was handled by: Sorin J. Brull, MD.

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ACKNOWLEDGMENTS

The authors thank Miss Jessica Bourke for her help with the English revision of the manuscript.

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