Hemodynamic monitoring
infection
INFECTION
After induction of anesthesia, a 20-G radial arterial line was inserted and connected to a pressure transducer. The invasive arterial blood pressure and PPV were continuously displayed on an Intellivue MP70 patient monitor (Philips Medical Systems, Germany) in real time. The radial arterial catheter was also connected to a dedicated transducer (FloTracPulse pressure (PP) was defined as the difference between systolic and diastolic arterial pressures. The maximal pulse pressure (PPmax) and minimal pulse pressure (PPmin) values were determined during the same respiratory cycle. PPV was automatically computed with the following formula: PPV(%) = (PPmax-PPmin)/[( PPmax+PPmin)/2]. In addition, SVV was defined as the beat-to-beat SV variation from the mean value during the past 20 sec and calculated with the following equation: SVV=(SVmax –SVmin)/SVmean [Sonographic measurement of IJVV was performed with a Philips CX50 ultrasound device (Philips Healthcare, Hamburg, Germany), equipped with a linear transducer. IJVV was measured by the same anesthesiologist with sufficient experience in ultrasound-guided IJV cannulation. The anesthesiologist performing the ultrasound examinations was not involved in this study and blinded to the hemodynamic parameters; a lead plate separated the monitor from the anesthesiologist and ultrasound device. The optimal short axis of the IJV was obtained at the level of the cricoid cartilage by placement of the transducer perpendicular to the skin on the patient’s neck in a transverse plane. The vein was identified with color Doppler imaging as well as by compression. Ultrasound measurements were performed on the left IJV, to minimize the risk of infection at the right IJV puncture site.An M-mode scan was used to record the IJV diameter at the end of inspiration (IJVmax) and expiration (IJVmin) over an entire respiratory cycle. The images were then frozen (Fig. Representative ultrasound image of the IJVV. IJVV, respiratory variation in the internal jugular vein