How Deep May We Insert the Cannulation Needle for Catheterization of the Internal Jugular Vein in Pediatric Patients Undergoing Cardiovascular Surgery?

To the Editor: Central venous catheterization is indispensable in patients undergoing cardiovascular surgeries for pressure monitoring and drug therapy. Although the internal jugular vein (IJV) approach is an attractive technique because of its simplicity and high success rate even in pediatric patients [1], the percutaneous IJV catherization is associated with several complications, including accidental arterial puncture [1,2]. An accidental deep insertion of the cannulation needle would facilitate puncture of the vertebral artery, which may cause a lethal consequence despite rare occurrence [3,4]. Although the deep insertion may easily occur in pediatric patients because of small body size, data on the depth of insertion of the needle for accessing the IJV are not available. In this study, we measured the depth of insertion of the needle for reaching the IJV during cannulation in pediatric patients undergoing cardiovascular surgeries. With institutional approval, we catheterized the right IJV of 73 pediatric patients placed in the 15 degrees Trendelenburg position with the high approach [5] and measured the depth of the IJV during pilot venipuncture with a 25-gauge needle. We slowly advanced the needle, keeping constant negative pressure on the syringe at 45 degrees to the skin surface until blood was aspirated; if blood was not aspirated on insertion, the needle was slowly withdrawn until blood was aspirated. The depth of the IJV was assessed by calculating the entire length of the needle minus the length of needle from skin surface to hub. Data were expressed as mean +/- SD. A simple regression was calculated to determine the lines of best fit. There was a weak but statistically significant correlation of the depth of the IJV with the patient's age, weight, and height (r = 0.45, 0.46, and 0.50, respectively; P < 0.01) Figure 1. We chose height as a variable and created a simple and clinically practical guide to determine the depth of the IJV for four grouped intervals of patient height Table 1.Figure 1: The relationship between the depth of the internal jugular vein (IJV) and age (A), weight (B), and height (C) of pediatric patients.Table 1: Depth of the IJV of Pediatric Patients for Four Grouped Intervals Based on Patient HeightIt is desirable not to go through the IJV during the catheterization, but blood aspiration is not always seen during insertion of the needle, even if the IJV is cannulated [6]. Thus, it seems to be clinically difficult to avoid penetrating the IJV. Recent application of ultrasound-guided cannulation has provided visualization of the IJV, which allows measurement of the exact depth of the IJV below the surface of the skin and prevents deep insertion, thus avoiding penetration of the IJV [7-9]. However, this technique is not always available in every hospital because of the cost of the equipment [10]. Although the depth of the IJV in our study was greater than the depth measured by ultrasound [9], the depth of the IJV in this study was equal to the length of the cannulation needle for reaching the IJV when we inserted the needle at an angle of 45 degrees. Therefore, we believe that our data are more adaptable to clinical situations. We believe that the present data will provide a useful guide in anesthesia training to prevent excessively deep insertion of the needle in pediatric patients. Kouich Maruyama, MD Yukio Hayashi, MD Yoshihiko Ohnishi, MD Masakazu Kuro, MD Department of Anesthesiology, National Cardiovascular Center, Suita Osaka 565, Japan