Efficacy of Subclavian Vein/Artery Diameter Index in Predicting the Incidence of the Spinal-Induced Hypotension in Geriatric Patients

The right SCV was measured using a linear array probe, placed in the sagittal plane at the deltopectoral triangle (beneath the proximal part of the middle of the clavicle and the area below the clavicle). In M-mode, measurements of SCV internal anteroposterior diameter, which is maximum during expiration (SCVmax) and minimum during inspiration (SCVmin), were taken in one respiratory cycle. Ultrasound scan of the patient's supraclavicular area showing the subclavian artery. The index was calculated as the ratio between the SCV maximum diameter and the SAD diameter

The IVC measurement will be obtained in the M-mode scan using a curvilinear (3.5 to 5 MHz) ultrasound transducer. The transducer was placed longitudinally in the subxiphoid region. The IVC maximum and minimum anterior-posterior diameters were obtained just distal to the IVC-hepatic vein junction. In M-mode, measurements of IVC internal anteroposterior diameter, which is maximum during expiration (IVCmax) and minimum during inspiration. IVCmin), were taken in one respiratory cycle. The abdominal aorta was identified to the left of the IVC, 10 mm above the coeliac trunk. The maximum internal anterior-posterior diameter of the aorta was obtained during systole. The caval /aorta diameter index was calculated as the ratio between the IVC maximum diameter and the aortic diameter. The index had a sensitivity of 96%, a specificity of 88%, and an accuracy of 95% to predict PSAH at a cut-off point of less than 1.2