Subclavian Versus Inferior Vena Cava Collapsibility Indices.

Study Overview
=================
Brief Summary
-----------------
Traditional methods for intravascular volume status assessment include physical examination, raised leg test, central venous pressure (CVP) and pulmonary artery catheters occlusion pressure (PAWP). Central venous pressure and pulmonary artery occlusion pressure are invasive and associated with significant complications. More recently, a number of less invasive techniques have been introduced, but they lack standardization and reliability. Ultrasonically, inferior vena cava collapsibility can detect hypovolemia non-invasively.

Detailed Description
-----------------
The aim of this study is that measurement of subclavian vein collapsibility index(SCV-CI) could be potential adjunct to IVC-CI where the IVC visualization is impaired or not possible . -Finding a non-invasive reliable accurate method for evaluation of intravascular volume and response to volume resuscitation.

Official Title
-----------------
Reliability of Subclavian Vein Versus Inferior Vena Cava Collapsibility Indices for Preload Assessment.

Conditions
-----------------
Hemodynamic Instability

Intervention / Treatment
-----------------
* Diagnostic Test: inferior vena cava collapsibility
* Diagnostic Test: subclavian vein collapsibility
* Diagnostic Test: central venous pressure


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 1. American society of anaesthesiologists physical status grade I and grade II . 2. Elective laparotomy. 3. Supine position Exclusion Criteria: Patient refusal . Portal hypertension . Severe peripheral vascular diseases. Obstructive lung diseases . Right sided heart failure , arrhythmia and valvular heart heart diseases . Body mass index >35 kg/m2

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Inferior Vena Cava Collapsibility<br>inferior vena cava diameters is obtained in the supine position with a convex probe .The probe is placed in the subxiphoid region or the right anterior midaxillary plane.The sagittal section of IVC is imaged. M-mode probe is used to identify the measurement of minimum and maximum venous dimensions over the respiratory cycle using the 3.5-5 MHz phased array probe. To standardize the measurements, measuring of the IVC diameter is performed at 2 cm caudal of the junction point of the right atrium and IVC. The difference between the maximum (D max) and minimum (D min)diameters of the target vein is normalized according to the standard formula to yield the collapsibility index (CI). | Diagnostic Test: inferior vena cava collapsibility<br>* inferior vena cava diameters is obtained in the supine position with a convex probe .The probe is placed in the subxiphoid region or the right anterior midaxillary plane.The sagittal section of IVC is imaged. M-mode probe is used to identify the measurement of minimum and maximum venous dimensions over the respiratory cycle using the 3.5-5 MHz phased array probe. To standardize the measurements, measuring of the IVC diameter is performed at 2 cm caudal of the junction point of the right atrium and IVC. The difference between the maximum (D max) and minimum (D min)diameters of the target vein is normalized according to the standard formula to yield the collapsibility index (CI).<br>|
| Experimental: Subclavian Vein Collapsibility<br>Right SCV diameters is checked in the supine position using a high frequency linear array probe (6-13 MHz) and M-mode. To standardize the measurements, the probe is placed beneath the proximal part of the middle part of the clavicle perpendicular to long-axis of the SCV to obtain the best cross-sectional view of the vien. After the target vein is localized , the dynamic diameter change is recorded using M-mode to identify and measure the minimum and maximum venous diameters.To calculate SCV collapsibility index, the standard formula is used. | Diagnostic Test: subclavian vein collapsibility<br>* Right SCV diameters is checked in the supine position using a high frequency linear array probe (6-13 MHz) and M-mode. To standardize the measurements, the probe is placed beneath the proximal part of the middle part of the clavicle perpendicular to long-axis of the SCV to obtain the best cross-sectional view of the vien. After the target vein is localized , the dynamic diameter change is recorded using M-mode to identify and measure the minimum and maximum venous diameters.To calculate SCV collapsibility index, the standard formula is used.<br>|
| Active Comparator: central venous pressure<br>ultrasound guided 7.5-F central venous catheter is introduced via right internal jugular vein under local analgesia with 2% lidocaine for measuring the CVP. | Diagnostic Test: central venous pressure<br>* ultrasound guided 7.5-F central venous catheter is introduced via right internal jugular vein under local analgesia with 2% lidocaine for measuring the CVP.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| inferior vena cava collapsibility index changes | ultrasound M mode maximum minus minimum over maximum then multiply by 100 | intraoperative changes:1st basal before induction of anesthesia, 2nd before start of surgery, 3rd after10 ml/kg ringers preload, 4th 5 minutes before extubation. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| subclavian vein collapsibility index changes | ultrasound M mode maximum minus minimum over the maximum then multiply by 100 | intraoperative changes:1st basal before induction of anesthesia, 2nd before start of surgery, 3rd after 10 ml/kg ringers preload, 4th 5 minutes before extubation. | 
| central venous pressure changes | centimeter water | intraoperative changes:1st basal before induction of anesthesia, 2nd before start of surgery, 3rd after 10 ml/kg ringers preload, 4th 5 minutes before extubation. | 
| heart rate changes | beat per minute | intraoperative changes:1st basal before induction of anesthesia, 2nd before start of surgery, 3rd after 10 ml/kg ringers preload, 4th 5 minutes before extubation. | 
| mean blood pressure changes | millimeter mercury | intraoperative changes:1st basal before induction of anesthesia, 2nd before start of surgery, 3rd after 10 ml/kg ringers preload, 4th 5 minutes before extubation. | 
| fluid administration | milliliter | Intraoperative | 
| blood loss | milliliter | intraoperative | 
| urine output | milliliter | intraoperative |