Internal Jugular Vein and Spinal-induced Hypotension

Study Overview
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Brief Summary
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The study aims to assess internal jugular vein ultrasound derived measurements and indices prior to spinal anesthesia in elderly population who fulfills predetermined inclusion criteria and might greatly benefit from an appropriate hemodynamic control during orthopedic surgery. Therefore, it is evaluated the diagnostic performance of these indices in predicting spinal-induced hypotension in this subset of participants.

Detailed Description
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Study design. The present, observational, prospective study, will be conducted over a 12-month period, 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 Heart Association/American College of Cardiology (AHA/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 included severe pulmonary hypertension, tachycardia (heart rate > 100 beats/min), atrial fibrillation with heart rate> 100 beats/min and severe valvular diseases. Additionally, all patients who had spinal anaesthesia and the maximum cephalad dermatomal extension of the sensory block was below T12 were excluded from the study. Arterial hypotension related to overt intra-operative bleeding (>150 cc) or patients requiring blood transfusion, for any reason, were not considered in the statistical analysis Duplex carotid ultrasound protocol and measurements. Ultrasonographic measurements is performed by an anaesthesiologist with prior training, supervised by physician component and certified to cardiovascular imaging techniques. After the patients is placed in the supine position, using GE-T8 Ultrasound System device, the carotid artery is visualized on the short axis with a 5-10 MHz linear probe in B-mode. Subsequently, the probe notch was rotated 90° to the head of the patient, and the carotid artery image is obtained in long axis orientation. The diameter of the right CA (RCA) is found by measuring between the intima layers of both vessel walls approximately 2-3 cm proximal to the carotid bulb. Then, pulse-wave Doppler imaging is performed again on the same image, the Doppler angle is adjusted to 50-60°, and the flow through the carotid artery of the patient is displayed as a Doppler spectrum. CA blood flow peak velocity (V peak), systolic and total VTI, flow time (FT), carotid corrected (ccFT), were measured prior to spinal anaesthesia. ccFT values are calculated using Wodey's formula, ccFT= FT+1.29(HR-60), which has been shown to better correct for fast heart rates in comparison to widely used Bazett's formula. FT is measured from the beginning of the systolic upstroke to the dicrotic notch. Patients with plaque thickness equal or greater than 2.5 mm in the examined common carotid artery. To visualize both IJVs 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 over a single respiratory cycle. Patients with evidence of IJV thrombosis are excluded. IJVs measurements included the antero-posterior maximum diameter at the end of expiration (IJVmax), the antero-posterior mimimum diameter at the end of inspiration (IJVmin), the IJV collapsibility index (IJV-CI) during spontaneous, quiet, breathing, [(IJVmax -diameter)/IJVmax] and the ratio (R) of IJVmax-to-IJV-CI. Two examiners each performed all the measurements two times, generating four values; the mean of these values was used for analysis. 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. Patients who experienced 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 (duration greater than or equal to 2 min time-period: from spinal anesthesia induction to the end of surgery). Arterial hypotension related to bone cement application, tourniquet deflation, overt intraoperative/postoperative bleeding (blood loss>150cc) or patients having received blood transfusion for any reason were not considered in our statistical analysis. The degree of sensory block (cold test) is assessed by an anesthesia nurse not further involved in the study. Sample size: Previously, many echocardiographic indices have been used to predict spinal-induced hypotension. The collapsibility index of the inferior vena cava has showed an area under the curve in a receiver operating characteristic curve analysis between 0.77. We hypothesized, therefore, that the area under the curve of the right or the left IJV-CI would be at least 0.77 to predict spinal induced hypotension. We calculated the required sample size for the comparison of the area under a receiver operating characteristic curve with a null hypothesis value. Considering the α error of 0.05 with 80% power, 32 patients are needed. To allow for a possible 20% dropout rate, we use a sample size of 38 patients.

Official Title
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Internal Jugular Vein and Carotid Artery Ultrasound for the Prediction of Spinal-induced Hypotension in Elderly Patients With Orthopaedic Trauma

Conditions
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Haemodynamic Instability

Intervention / Treatment
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* Diagnostic Test: Vacular Ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Elderly patients with orthopaedic trauma of the lower limb, American Heart Association/American College of Cardiology (AHA/ACC) stage I or II, Cardiac disease is in a compensated status. Exclusion Criteria: Atrial fibrillation, tachycardia (heart rate > 100 beats/min) Sensory block less than T12 Severe valvular disease Severe pulmonary hypertension Overt bleeding

Ages Eligible for Study
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Minimum Age: 70 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Vacular Ultrasound|To visualize the internal jugular veins ( IJVs) a linear transducer with a 5-10 MHz linear probe was placed over the neck, and the IJV was measured just below the bifurcation of the sternal and clavicular heads of the muscle. The IJV measurements were performed on the transverse axis over a single respiratory cycle. Patients with evidence of IJV thrombosis were excluded. IJV measurements included the antero-posterior maximum diameter at the end of expiration (IJVmax), the antero-posterior mimimum diameter at the end of inspiration (IJVmin), the IJV collapsibility index (IJV-CI) during spontaneous, quiet, breathing, [(IJVmax - IJVmin diameter)/IJVmax] and the ratio (R) of IJVmax-to-IJV-CI.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Internal jugular vein diameters (mm) prior to spinal anesthesia implementation | Using GE-T8 Ultrasound System device, the right internal jugular vein is visualized on the short axis with a 5-10 MHz linear probe in B-mode. | 10 minutes prior to spinal anesthesia | 
| Carotid artery flow velocities (cm/sec) prior to spinal anesthesia implementation | Using GE-T8 Ultrasound System device, the right carotid artery is visualized on the long axis with a 5-10 MHz linear probe in B-mode. Pulse wave doppler technique is used to measure flow velocities. | 5 minute as prior to spinal anesthesia |