Central Venous Access in Morbidly Obese Patients

Abstract

To the Editor: Johnson and Tobias describe the use of a spinal needle for central venous cannulation in the morbidly obese patient (1). We agree that vascular access can be technically challenging in these patients. However, we emphasize that blind attempts at cannulation, especially in patients in whom anatomic landmarks are obscured, is potentially dangerous. We advocate that the most reasonable approach in terms of efficacy and safety is to use real-time ultrasound guidance. This has been shown to significantly increase the probability of successful catheter placement, reduce complications, and decrease the need for multiple insertion attempts (2). The benefits of ultrasound guidance may be even more obvious in the morbidly obese. In a study of patients with difficult central venous access, a 100% success rate was demonstrated with ultrasound guidance (3). Real-time ultrasound may well demonstrate that the use of standard equipment is feasible. Alternatively, it could allow the safer use of unorthodox equipment. Central venous cannulation is a procedure that is not without risk. Experience suggests that these risks may be greater in the obese. Blind attempts at central venous cannulation are not the answer. Ultrasound guidance is a safe, cheap, and effective solution. Paul Jefferson, FRCA David R Ball, FRCA