A Correlation Study in the Intensive Care Unit Between the Respiratory Variation Ratios of Internal Jugular Vein and Inferior Vena Cava Before and After Passive Leg Raise
Conditions: Critically Ill
Sponsor: Hacettepe University

 
ClinicalTrials.gov ID: NCT04173741  
 
 
Brief Title: Is There Any Correlation Between Respiratory Variation Ratios of Internal 
Jugular Vein and Inferior Vena Cava? 
 
 
Official Title: A Correlation Study in the Intensive Care Unit Between the Respiratory 
Variation Ratios of Internal Jugular Vein and Inferior Vena Cava Before and After Passive 
Leg Raise 
 
 
Date: 01 December 2019 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Study Protocol: For this prospective observational study, we took consent of the Hacettepe 
University Non-Interventional Clinical Researches Ethics Board (GO 17/427-34). All adult 
(aged 18 or older) mechanically ventilated patients admitted consecutively to Hacettepe 
University Hospital Anesthesiology Intensive Care Unit were screened for study eligibility. 
Patients with infection or surgical sutures in the site of measurement areas, intraabdominal 
hypertension, severe aortic regurgitation or lower extremity amputation history were excluded 
from the study. For eligible patients, we took informed consent from patients themselves or 
from their guardians.  
Ultrasonography (USG) measurements were done separately by 3 different physicians; one 
senior anesthesiology resident, one critical care medicine fellow (who joined two hands-on 
USG training before) and one professor in anesthesiology and critical care (USG trainer with 
more than 1000 USG measurement experience). Anesthesiology resident took 2 hours of 
didactic lecture about IJV and IVC ultrasonography and performed 5 practices under 
supervision of the instructor before starting the USG measurements for this study. Physicians 
neither watched each other’s measurements nor were informed about each other’s 
measurement values. 
The diameters of inferior vena cava (IVC) and internal jugular vein (IJV) were measured in 
two different positions. First measurements of IVC and IJV were done in supine position and 
second ones were done after passive leg raise (PLR) maneuver. For the passive leg raise 
maneuver legs were elevated 45 degrees. USG measurements were performed 1-3 minutes 
after PLR. 
Philips CX50 Ultrasonography Machine (Philips Ultrasound, Andover, MA, USA) was used 
for all of the measurements. IJV diameter was measured in the short axis by using linear 
probe (12-5 MHz) and M-mode. IJV visualized in the junction of cricothyroid membrane 
level and midclavicular line. Maximum and minimum diameter values were measured in the 
M mode. 
IVC was visualized in the subxiphoid long axis by using convex probe (5-1 MHz). Maximum 
and minimum diameters of IVC was measured 2 cm caudally to the junction of hepatic vein in 
M-mode. 
Distensibility (maximum diameter – minimum diameter / minimum diameter) and 
collapsibility (maximum diameter – minimum diameter / maximum diameter) indices were 
calculated after USG measurements were done. 
Oxygen saturation, heart rate and blood pressure levels were recorded before and after 
measurements. We also recorded age, gender, weight, height, body mass index, causes of 
admission, comorbidities, ventilator settings, vasoactive and diuretic medications, fluid intake 
and output volumes, Acute Physiology and Chronic Health Evaluation (APACHE) II and 
Sequential Organ Failure Assessment (SOFA) scores in the day of admission, Acute 
Physiology Score (APS) and SOFA scores on the day of measurement and length of stay in 
intensive care unit. 

Statistical Analysis: We calculated that 44 patients should be included in this study to 
investigate correlation between IVC and IJV measurements with 0.4 effect size, 0.05 Alfa 
error and 0.80 power by using G*Power 3.1 software. A total of 46 patients in Hacettepe 
University Hospital Anesthesiology Intensive Care Unit were required to enroll into this study 
to reach that number of patients. 
We used “IBM SPSS Statistics 23” for statistical analysis. Distribution of the data was 
analyzed with Kolmogorov- Smirnov Test. For normally distributed data we calculated mean 
and standard deviation, for the others we calculated median and percentile [5-95] values. We 
used Spearman correlation test for correlation analysis of measurements of different 
physicians. We used Spearman correlation test to analyze the correlations between IVC and 
IJV measurements. Subgroups were listed as patients on vasopressors vs no vasopressors, 
patients on vasodilators vs no vasodilators, patients on diuretics vs no diuretics, patients with 
20mmHg and over vs <20 mm Hg plateau pressure levels, patients with 15mmHg and over vs 
<15 mm Hg driving pressure levels, patients with over 5mmHg PEEP levels vs PEEP<5 mm 
Hg,  patients with surgical cause of admission vs others, patients who were stayed 1 minute in 
passive leg raise position vs patients who were stayed 3 minutes in passive leg raise 
position. A p value less than .05 was considered statistically significant.