Relationship between Trendelenburg tilt and internal jugular vein diameter

Abstract

Objectives: To evaluate the relationship between Trendelenburg tilt and internal jugular vein (IJV) diameter, and to examine any cumulative effects of tilt on the IJV diameter. Methods: Using a tilt table, healthy volunteers were randomised to Trendelenburg tilts of 10˚, 15˚, 20˚, 25˚, and 30˚. Ultrasound was used to measure and record the lateral diameter of the right IJV at the level of the cricoid cartilage. Following each reading the table was returned to the supine position. Balanced randomisation was used to assess cumulative tilt effects. Results: A total of 20 healthy volunteers were recruited (10 men, 10 women). Mean supine IJV diameter was 13.5 mm (95% CI 12.8 to 14.1) and was significantly greater at 10˚(15.5 mm, 95% CI 14.9 to 16.1). There was no significant difference between 10˚and greater angles of tilt. The effect of the previous angle of tilt did not prove to be statistically significant. Conclusion: Increasing the degree of Trendelenburg tilt increases the lateral diameter of the IJV. Even a 10t ilt is effective. The cumulative effect of tilt (that is, the effect of the previous angle) is not significant. Ultrasound guided cannulation is ideal, but in its absence Trendelenburg tilt will increase IJV diameter and improve the chance of successful cannulation. While 25˚achieved optimum distension, this may not be practical and may be detrimental (for example, risk of raised intracranial pressure).T he UK National Institute of Clinical Excellence (NICE) guidelines 1 recommend the use of real time ultrasound guidance for internal jugular vein (IJV) cannulation. However, a recent study has shown that the majority of emergency departments (EDs) in the island of Ireland do not use ultrasound.2 Although strictly speaking these departments do not fall under the jurisdiction of NICE, the pattern of ultrasound usage in EDs is likely similar to that in mainland UK. In the absence of ultrasound guidance the Trendelenburg position is often used in IJV cannulation to increase the diameter of the IJV.Our study aimed to evaluate the relationship between Trendelenburg tilt and the IJV diameter and to examine any cumulative effects of tilt on the IJV diameter. METHODA statistical analysis before the study predicted that 20 subjects would be required for sufficient power, and compared favourably with other similar studies. 3The procedure was carried out by a single examiner (SC) using healthy volunteers selected at random. The subjects had no history of neck problems or previous IJV cannulation.Each subject was placed supine on a tilt table, with an inbuilt clinometer that was raised and lowered on an electric motor. The level of the cricoid cartilage was marked and the right IJV was identified using real time ultrasound (Medison 128 BW high frequency linear probe). Lateral IJV diameter was measured at this level over three respiratory cycles and the maximum diameter was recorded prior to tilt. The subject then was tilted to 10˚, 15˚, 20˚, 25˚, and 30T rendelenburg. For each angle, subjects were kept in position fo...

The Effects of Trendelenburg Position, Positive Intrathoracic Pressure and Head Rotation on Cross-sectional Area of Internal Jugular Vein

“…Trendelenburg pozisyonunun etkisi veya etkisizliği, eğer etkisi var ise hangi eğimde bir trendelenburg pozisyonunun efektif olduğu halen tartışmalı olmakla beraber, 10˚, 15˚, 20˚, 25˚ ve 30˚ trendelenburg eğim-lerinin karşılaştırıldığı bir sağlıklı gönüllü çalışma-sında trendelenburgun İJV çapını anlamlı bir şekilde arttırdığı ancak dereceler arasında farkın olmadığı yani 10˚'lik bir trendelenburg eğiminin bile anlamlı olarak İJV çapını arttırdığı gösterilmiştir [21] .…”

Evidence-Based Practice Habits: Putting More Sacred Cows Out to Pasture

“…Distension of the internal jugular vein has been measured and is increased in head-down tilt, but internal jugular blood flow is unchanged. Researchers disagree on the effect of the Trendelenburg position on intracranial pressure and cerebral blood flow, with some concluding that those factors do increase, 32 while others conclude that cerebral hemodynamics are not affected. 22 One clinical protocol that uses Trendelenburg positioning for postural drainage of the lungs in patients with brain injury originally incorporated criteria based on changes in intracranial pressure and cerebral perfusion pressure 33 and now also includes reduced brain tissue oxygenation for more precision, as the basis for returning the patient to supine or head-up position.…”

“…Little research is available on the effect of Trendelenburg position on intracranial pressure; however, some agree that it is likely to increase intracranial pressure because of the increased central venous pressure, 17,24,[30][31][32] but the effects on cerebral blood flow are uncertain. Distension of the internal jugular vein has been measured and is increased in head-down tilt, but internal jugular blood flow is unchanged.…”

“…Table 3 provides a summary of the evidence and physiological response to the Trendelenburg position. 17,21,24,25,[27][28][29][30][31][32] Alternatives to Trendelenburg positioning, such as passive leg lift, may provide greater benefit for initial management of hypotension or prediction of fluid responsiveness with minimal or no untoward effect. 34,35 Raising the patient's legs while keeping the head of the bed horizontal relative to the patient's trunk produces an approximate volume shift of 150 to 300 mL to the upper part of the thorax.…”

Ultrasound validation of Trendelenburg positioning to increase internal jugular vein cross-sectional area in chronic dialysis patients

“…All of the patients were positioned with their neck in extension and head rotated left at [20][21][22][23][24][25][26][27][28][29][30] . Patients were studied in State 0, table flat (no tilt), with the patients in the supine position, and State T, in which the operating table was tilted 15 to a TP.…”