Comparison of Stroke Volume Variation-based goal-directed Therapy Versus Standard Fluid Therapy in Patients Undergoing Head and Neck Surgery: A Randomized Controlled Study

Background: Perioperative fluid therapy is used to avoid dehydration and hypovolemia. Optimum perioperative fluid administration may improve postoperative outcomes after major surgery, and the optimal strategy remains controversial and uncertain. Aims: The primary outcome was the total amount of intraoperative fluids given between perioperative goal-directed fluid therapy (GDFT) guided by a hemodynamic monitoring system and standard fluid therapy based on "mean arterial pressure-diuresis" data in patients undergoing head and neck surgery. The secondary outcomes were the hemodynamics and laboratory variables, postoperative complications, length of mechanical ventilation, intensive care unit and hospital stay. Study Design: A randomized controlled study. Methods: Sixty patients were scheduled and randomized into two groups of 30 patients each: in the study group, an arterial pressure catheter was inserted and connected to the FloTrac system, whereas in the control group, an arterial pressure catheter was inserted and integrated into the hemodynamic monitoring system with a special transducer. The control group had fluids administered at the discretion of the anesthesiologist according to the mean arterial pressure >65 mmHg and diuresis >0.5 ml/kg/h. In the study group, fluid management was administered to achieve a target value of ≤13% through the stroke volume variation. Results: The total amounts of fluid in the intraoperative period were different between the groups, with the study group receiving significantly more fluids (P = 0.0455). The length of hospital stay was significantly longer in the study group than in the control group (P = 0.012), but prolonged oxygen demand was significantly more frequent in the control group than in the study group (P = 0.017). No difference was found in hemodynamics, lactate kinetics, and vasoactive agent requirements. Conclusion: The standard fluid therapy guided by conventional circulatory parameters appears sufficient for patients with low-tomoderate risk during head and neck surgery.

Role of ultrasonography in determining the cricothyroid membrane localization in the predicted difficult airway.

BACKGROUND: The aim of this study was to investigate the success rates of ultrasound (US) and palpation methods in identifying the cricothyroid membrane (CTM), and compare the results with the gold standard method-computed tomography (CT) scan. METHODS: A total of 110 patients were included into the study. The midline was estimated by a single investigator using both the US and palpation methods from the prominence of the thyroid cartilage to the center of the sternal notch, and the distance was measured (in millimeters) between the two points: Point A (the midpoint of CTM) and Point B (the inferior process of thyroid cartilage). Furthermore, the distance between Point A and Point B was calculated using the CT images. Time taken to assess the CTM by using US and palpation methods were recorded. Moreover, difficulty in using the two methods was measured with the visual analog scale (VAS). In addition, demographic and morphometric characteristics of the patients were noted. RESULTS: The CTM was detected accurately in 50 (45.5%) patients with palpation and 82 (74.5%) with US. In the Bland-Altman analysis, a better agreement was observed with US. The time to assess CTM was shorter with US than with palpation, p<0.001. The VAS scores for the palpation and US difficulty were 5.13+-1.1 and 3.32+-0.9 (p<0.001), respectively. While an increased neck circumference and thyromental distance were found to be independent risk factors for the success rates of determining the CTM by palpation, body mass index is an independent risk factor for US. CONCLUSION: Localization of the CTM is more accurate and easier with US than palpation. Furthermore, the results gathered with US are in a closer range to CT scan.