Internal Jugular Vein Ultrasound for the Prediction of Spinal-induced Hypotension in Elderly Patients With Orthopaedic Trauma

1. Study design. The present, observational, prospective study, will be conducted over a 12-month period,
2. Population. Consecutive sampling is used to recruit aging patients (>70 years), who sustain trauma of the lower limb and underwent an orthopedic surgical procedure under spinal anesthesia.

More specifically, patients included, are subjected to an orthopaedic surgical repair of a proximal femur fracture under spinal anaesthesia. Patients' medical history, physical examination, electrocardiogram (ECG), and X-ray assessment are performed during the pre-operative assessment, supplemented by specific exams or tests (e.g. TTE, troponin or pro-BNP levels) as per the consultant cardiologists' recommendations.

All patients in our study are American College of Cardiology (ACC) stage I OR II, and their cardiac disease status is compensated. As per departmental protocol and fasting guidelines, all patients could receive clear liquids and solid food until 2 and 8 hours before surgery, respectively. Creatinine and urea values and subsequently GFR are measured in all patients.

Exclusion criteria includes moderate or severe pulmonary hypertension, tachycardia (heart rate > 100 beats/min), atrial fibrillation with heart rate> 100 beats/min. Additionally, all patients who has spinal anaesthesia and the maximum cephalad dermatomal extension of the sensory block is below T12 are excluded from the study. Arterial hypotension related to overt intra-operative bleeding (>150 cc) or patients requiring blood transfusion, for any reason, is not considered in the statistical analysis 3. POCUS IJV ultrasonography To visualize both the right and left IJV a linear transducer with a 5-10 MHz linear probe is placed over the neck, and the IJV is measured just below the bifurcation of the sternal and clavicular heads of the muscle. The IJV measurements are performed on the transverse axis during spontaneous quiet, breathing. Patients with evidence of IJV thrombosis are excluded. IJV measurements included the maximum area at the end of expiration (IJVmax), the minimum area at the end of inspiration (IJVmin), the IJV collapsibility index (IJV-CI): [(IJVmax - IJVmin diameter)/IJVmax] and the ratio (R) of IJVmax-to-IJV-CI. Two examiners each performed all the measurements, generating two values; the mean of these values is used for analysis. 4. Anesthetic protocol and measurements. Spinal anesthesia is introduced with a single intrathecal injection of 0.75% (15 mg) plain ropivacaine using a 22 or 25-gauge needle with the patient in the lateral or sitting position. Intraoperative ECG, SPO2 and non-invasive blood pressure (measurements every two minutes) monitoring are routinely used. The non-invasive blood pressure is measured every 2 minutes and vital parameters are recorded continuously throughout surgery.

Patients experiencing a MAP less than or equal to 65 mmHg, or greater than or equal to 25% reduction of its baseline preoperative value is considered hypotensive Arterial hypotension related to bone cement application, intraoperative/postoperative bleeding with blood loss greater than 150cc or patients receiving blood transfusion for any reason are not considered in our statistical analysis.