Maternal placental vascular compliance in rabbits

1978 ◽  
Vol 234 (3) ◽  
pp. H289-H292
Author(s):  
G. L. Brownfield ◽  
R. D. Gilbert ◽  
G. G. Power
Keyword(s):  
Blood Volume ◽  
Inferior Vena ◽  
Venous Pressure ◽  
Vena Cava ◽  
Placental Tissue ◽  
Total Resistance ◽  
Intervillous Space ◽  
New Zealand White Rabbits ◽  
Placental Blood ◽  
Placental Volume

We studied compliance on the maternal side of the placenta of 20 New Zealand white rabbits, using 51Cr and 125I labels to determine erythrocyte, plasma, and whole-blood volumes per gram of placental tissue under varying maternal pressure conditions. At normal maternal arterial (Pa) and venous (Pv) pressures of 71.8 and 5.5 mmHg, placental blood volume (mean +/- SE) was 0.447 +/- 0.051 ml/g placental tissue. When venous pressure was raised (Pa = 45.5, Pv = 12.2) by occluding the inferior vena cava, blood volume increased to 0.729 +/- 0.068 ml/g, a significant 63% rise. However, when arterial pressure was lowered by occluding the aorta in two steps, dropping to Pa = 33.8, Pv = 7.0, and Pa = 13.5, Pv = 5.4, volume did not decrease significantly. We estimated intervillous space pressure (Pivs) from arterial and venous pressures assuming a ratio of venous to total resistance of 0.02. Compliance calculated from the slope of Pivs vs. volume was 0.0471 ml/mmHg per g. Maternal placental hematocrit averaged 27%, appreciably less than the circulating hematocrit of 38%. Overall, the results suggest that placental volume would be maintained during hypotension and would increase when venous pressure is elevated.

Effect of hypoxic hypoxia on systemic vasculature

1984 ◽  
Vol 56 (5) ◽  
pp. 1403-1410 ◽  
Author(s):  
J. Malo ◽  
H. Goldberg ◽  
R. Graham ◽  
H. Unruh ◽  
C. Skoog
Keyword(s):  
Arterial Pressure ◽  
Inferior Vena ◽  
Superior Vena ◽  
Venous Pressure ◽  
Vena Cava ◽  
Venous Drainage ◽  
Hypoxic Hypoxia ◽  
Venous Compliance ◽  
Flow Curves ◽  
Pressure Flow

Effects of hypoxic hypoxia (HH) on cardiac output (CO), CO distribution, arterial and venous pressure-flow curves, vascular compliance, vascular time constant (tau), and resistance to venous return (RVR) were evaluated on six dogs. The vascular bed was isolated into four compartments depending on venous drainage: superior vena cava (SVC), splanchnic, renal and adrenal, and the remainder of the inferior vena cava (IVC). Low arterial O2 content and PO2 produced a threefold increase in CO at the same mean arterial pressure and a significant redistribution of CO to the SVC. Arterial pressure-flow curves decreased their slope (i.e., flow resistance) by a factor of two in the IVC and renal beds and by a factor of three in the splanchnic and SVC beds. Venous pressure-flow curves for the animal also decreased their slope significantly. HH causes a twofold increase in venous compliance and in mean venous pressure; tau did not change, but RVR halved. Seventy percent of the CO increase is explained by the increase in mean venous pressure and 30% by the reduction in RVR.

scholarly journals Respiratory variation of inferior vena cava diameter and central venous pressure in ventilated and non-ventilated children in fluid refractory septic shock: an observational study

2019 ◽  
Vol 6 (5) ◽  
pp. 1947
Author(s):  
Mohd Kashif Ali ◽  
Eeman Naim
Keyword(s):  
Septic Shock ◽  
Inferior Vena Cava ◽  
Central Venous Pressure ◽  
Inferior Vena ◽  
Venous Pressure ◽  
Vena Cava ◽  
Central Venous ◽  
Mechanically Ventilated ◽  
Spontaneously Breathing ◽  
Ventilated Patients

Background: Ultrasound guided fluid assessment in management of septic shock has come up as an adjunct to the current gold standard Central Venous Pressure monitoring. This study was designed to observe the respiro-phasic variation of IVC diameter (RV-IVCD) in invasively mechanically ventilated and spontaneously breathing paediatric patients of fluid refractory septic shock.Methods: This was a prospective observational study done at Paediatric intensive Care Unit (PICU) in Paediatric ward of Jawaharlal Nehru Medical College and Hospital (JNMCH) from February 2016 to June 2017. 107 consecutive patients between 1 year to 16 years age who were in shock despite 40ml/kg of fluid administration were included. Inferior Vena Cava (IVC) diameters were measured at end-expiration and end inspiration and the IVC collapsibility index was calculated. Simultaneously Central Venous Pressure (CVP) was recorded. Both values were obtained in ventilated and non-ventilated patients. Data was analysed to determine to look for the profile of RV-IVCD and CVP in ventilated and non-ventilated cases.Results: Out of 107 patients, 91 were on invasive mechanical ventilation and 16 patients were spontaneously breathing. There was a strong negative correlation between central venous pressure (CVP) and inferior vena cava collapsibility (RV-IVCD) in both spontaneously breathing (-0.810) and mechanically ventilated patients (-0.700). Negative correlation was significant in both study groups in CVP <8 mmHg and only in spontaneously breathing patients in CVP 8-12 mmHg range. IVC collapsibility showed a decreasing trend with rising CVP in both spontaneously breathing and mechanically ventilated patients.Conclusion: Ultrasonography guided IVCCI appears to be a valuable index in assessing fluid status in both spontaneously breathing and mechanically ventilated septic shock patients. However, more data is required from the paediatric population so as to define it as standard of practice.

scholarly journals Measurement of Inferior Ven Cava Collapsibility Index and Its Correlation to Central Venous Pressure in Adult Critically Ill Patients a Prospective Observational Study

2020 ◽  
Vol 5 (1) ◽  
Keyword(s):  
Inferior Vena Cava ◽  
Central Venous Pressure ◽  
Inferior Vena ◽  
Venous Pressure ◽  
Vena Cava ◽  
Volume Status ◽  
P Value ◽  
Central Venous ◽  
Collapsibility Index ◽  
Status Assessment

Fluid therapy is an essential component part management of critically ill patients. Proper estimation of the amount of needed fluids is of great importance due to the well-established adverse effects of marked negative and positive fluids balance. Central venous pressure has been widely used by ICU physicians for volume status assessment. Several methods have been postulated for volume status assessment, among which is the inferior vena cava collapsibility index. As the inferior vena cava is a thin-walled capacitance vessel that adjusts to the body’s volume status by changing its diameter depending on the total body fluid volume. Giving the fact that bed-side ultrasonographic measurement of inferior vena cava diameters is an available, non-invasive, reproducible and quiet easy-to-learn technique, it can provide a safe and quiet reliable replacement of central venous pressure measurement for assessment of volume status assessment. The aim of this study was to find statistical correlation between central venous pressure and caval index, as a step towards validating the above mentioned replacement. 86 critically ill patients from ICU population were enrolled. Simultaneous measurements of central venous pressure and inferior vena cava collapsibility index were observed and recorded on four sessions. Patients were also grouped based on their mode of ventilation and central venous pressure values in order to compare the strength of correlation between various populations. The results showed that Inferior vena cava collapsibility index has significant inverse correlation with CVP value (r= -85, p value ˂0.001 at 95% CI) and it better correlated with mean arterial blood pressure and lactate clearance as compared to central venous pressure. However it correlated better with CVP in spontaneously breathing patients (r= -0.86, p value ˂0.001) than in mechanically ventilated patients (r= -0.84, p value ˂0.001). Inferior vena cava collapsibility index has shown to correlate better with CVP value in lower values (˂ 10 cmH2O) (r= -0.8, p value ˂0.001) than in higher values (≥ 10 cmH2O) (r= -0.6, p value ˂0.001). In addition, an inferior vena caval collapsibility index cut-off value of 29% was shown to discriminate between CVP values ˂10 cmH2O and values ≥10 cmH2O with high Sensitivity (88.6%) and specificity (80.4%). In conclusion, inferior vena cava collapsibility index has a strong inverse relationship with central venous pressure which is more pronounced at low central venous pressure values. Point-of-care ultrasonographically-measured inferior vena cava collapsibility index is very likely to be a good alternative to central venous pressure measurement with a high degree of precision and reproducibility. However, Wide scale studies are needed to validate its use in different patient populations.

A PROSPECTIVE OBSERVATIONAL STUDY TO ASSESS CORRELATION OF CAVAL AORTA INDEX WITH CENTRAL VENOUS PRESSURE FOR INTRAVASCULAR VOLUME ASSESSMENT IN PATIENTS UNDERGOING ENDOSCOPIC TRANSURETHERAL RESECTION OF PROSTATE (TURP)

2021 ◽  
pp. 10-12
Author(s):  
N. Senthil kumar ◽  
Jeya Pratheef Muthiah
Keyword(s):  
Prospective Observational Study ◽  
Inferior Vena ◽  
Venous Pressure ◽  
Vena Cava ◽  
Volume Status ◽  
Intravascular Volume ◽  
Central Venous ◽  
Sonographic Evaluation ◽  
Volume Assessment ◽  
The Mean

INTRODUCTION: There are various techniques for assessing the uid status such as clinical examination, central venous pressure (CVP) measurement, biochemical markers, bio impedance, continuous blood volume measurement, or sonographic inferior vena cava (IVC) diameter assessment. Sonographic evaluation of the IVC and Aorta diameter and its usefulness in evaluating the volume status are studied and documented. The sonographic evaluation of the IVC & Aorta can predict the volume status, this tool can assist anesthetist in rapid diagnosis and prompt resuscitation of patients developing TURP syndrome AIM OF THE STUDY: The aim & objective of this study is to assess the correlation of Caval Aorta index with CVP in intravascular volume assessment in patients undergoing endoscopic Trans Urethral Resection of Prostate (TURP) MATERIALS AND METHODS: The study is carried out in the Department of Anaesthesiology involving Department of Urology in Kanyakumari Government Medical College from January 2018 to June 2019. It is a Prospective observational study. To measure the IVC diameter USG machine probe is placed in the sub-xiphoid region to visualize the conuence of the hepatic veins draining the IVC. The maximum internal AP diameter of the Aorta(Ao) and maximum internal anterior-posterior (AP) diameter of the IVC is measured in the longitudinal plane. Fluid status will be measured by CVP and IVC/Ao index recorded before neuraxial block, after preload, at 5 min after intrathecal block, resection time at 0 min, every 15 min during the rst 30 min, then every 30 min, until the end of surgery. Outcome: Incidence of hypotension after spinal anesthesia in a cesarean section RESULTS: The mean IVC diameter at pre-operative is 15.20±1.42, and at 60 min, 75 min were 19.39±1.92, 20.03±1.76 which suggests that the size and shape of the inferior vena cava (IVC) is correlated to the CVP and circulating blood volume. In my study the mean Aortic diameter at 60 min, 75 min were 20.30±1.01 and 19.81±1.06 which is same as the preoperative level (19.72±1.18) and diameter. The mean CVP at pre-operative is 4.57±0.73, mean CVP at 60 min, 75 min were 7.57±0.82, 8.11±0.78 which denotes that CVP increases as the intravascular volume status increases. In our study mean IVC/Aortic index at pre-operative is 0.77±0.05 and the mean IVC/Aortic index at 15min, 30 min, 60 min, 75 min were 0.87±0.03, 0.90±0.04, 0.95±0.06, 1.01±0.05 which increases signicantly in increasing intravascular volume. The strong correlation between these two variable with Pearson formula ranging from 0.450-0.900. CONCLUSION: As Sonographic caval Ao index is very well correlated with CVP , IVC/Ao index is useful for the evaluation of preoperative and intraoperative volume status, especially in major surgeries with marked uid shift or blood loss and had the advantage of being noninvasive, safe, quick, and easy technique with no complications.

Cardiac variation of inferior vena cava: new concept in the evaluation of intravascular blood volume

2013 ◽  
Vol 40 (3) ◽  
pp. 205-209 ◽  
Author(s):  
Kensuke Nakamura ◽  
Makoto Tomida ◽  
Takehiro Ando ◽  
Kon Sen ◽  
Ryota Inokuchi ◽  
...  
Keyword(s):  
Inferior Vena Cava ◽  
Blood Volume ◽  
Inferior Vena ◽  
Vena Cava

P2473Non-invasive assessment of central venous pressure in heart failure: comparing three-dimensional echocardiography and Swan-Ganz catheter

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
T Szymczyk ◽  
L J Paluszkiewicz ◽  
A Costard-Jaeckle ◽  
V Rudolph ◽  
J F Gummert ◽  
...  
Keyword(s):  
Heart Failure ◽  
Inferior Vena ◽  
Venous Pressure ◽  
Three Dimensional ◽  
Vena Cava ◽  
Right Heart Catheterization ◽  
Heart Catheterization ◽  
Right Heart ◽  
Cross Sectional ◽  
Dimensional Echocardiography

Abstract Background Assessing hemodynamics, in particular central venous pressure (CVP) is essential in heart failure diagnostics, leading individual therapy. Hereby, invasive measurement through Swan-Ganz right heart catheterization (RHC) is considered gold standard for patient evaluation, but catheterization implies risks of invasiveness including bleeding, infection, vessel and nerve injury, as well as patient discomfort. Non-invasive methods are warranted, but no alternative technique is validated yet. Two-dimensional echocardiography (2DE) is believed to be uncertain in this approach as vena cava often shows ellipse-shapes. Therefore, this study sought to investigate standardized and breathing corrected three-dimensional inferior vena cava echocardiography (3DE) to directly compare CVP with right heart catheterization. Methods and results We prospectively included 100 consecutive heart failure patients in this study (mean age 53±12 years, body mass index 27±5, New York Heart Association functional class 2.3±0.6, left ventricular ejection fraction 34.1±12.8%, brain natriuretic peptide 658.13±974.03, 76% male), all underwent Swan-Ganz right-heart catheterization and immediately both 2DE and 3DE (Philips EPIQ 7G) of inferior vena cava. From two-dimensional data the diameter of IVC was measured perpendicularly in long and short-axis. From 3DE data a cross-sectional image of IVC was reconstructed for both vertical and horizontal diameters of IVC as well as the area of IVC. Established 2DE images revealed mean vena cava sizes of 15.9±5.9 mm, while standardized cross-sectional breathing corrected 3DE images showed diameters of 19.8±7.8 mm in longitudinal axis and 15.74±7.8 in short axis. RHC mean CVP was 9.00±5.4 mmHg and correlation of CVP and 2DE measurements failed adequate correlation (2DE 95% CI 0.19–1.61; r=0.25; p=0.312). However, 3DE axis ratio assessment correlated well with invasive CVP and showed reproducible results (3DE 95% CI 0.26–0.69; r=0.89; p<0.01). This resulted for a CVP cut point of 10 mmHg in a 89% true negative and 50% true positive correct detection. Conclusions Standardized 3DE correlates well with invasive CVP while established 2DE usual care assessment does not show reliable CVP correlation. 3DE CVP assessment may represent a more feasible and easily applicable method for CVP measurement, including absence for risks of right heart catheterization. Further studies are ongoing to validate these findings in the future.

Increased lymphatic pressure without increased neck vein pressure during intravenous infusions

1994 ◽  
Vol 266 (5) ◽  
pp. R1596-R1598
Author(s):  
J. C. Gabel ◽  
S. Dhother ◽  
R. E. Drake
Keyword(s):  
Inferior Vena Cava ◽  
Inferior Vena ◽  
Venous Pressure ◽  
Vena Cava ◽  
Lymphatic Vessels ◽  
Ringer Solution ◽  
Pressure Increase ◽  
Balloon Inflation ◽  
Intravenous Infusions ◽  
Infusion Period

Postnodal intestinal lymphatic pressure increases during rapid intravenous infusions with Ringer solution in sheep. Part of the lymphatic pressure increase is due to increased venous pressure at the lymphatic outflow (the neck veins). We tested the hypothesis that other factors besides increased neck vein pressure may cause increased lymphatic pressure during intravenous infusions. We placed cannulas into postnodal lymphatic vessels in eight sheep. After the sheep recovered from the surgery, we infused Ringer solution [46 +/- 21 (SD) ml/kg body wt in 30 min] intravenously into the sheep and inflated a balloon in the inferior vena cava. We adjusted the balloon inflation to prevent any increase in neck vein pressure during the infusions. At baseline, the intestinal lymphatic pressure was 15.5 +/- 2.5 cmH2O. During the infusions, lymphatic pressure increased significantly, and for the last 10 min of the infusion period, intestinal lymphatic pressure was 24.0 +/- 6.1 cmH2O. These results are consistent with the hypothesis that factors in addition to increased neck vein pressure may cause increased intestinal lymphatic pressure during rapid intravenous infusions.

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