Ultrasonographic assessment of inferior vena cava/abdominal aorta diameter index: a new approach of assessing hypovolemic shock class 1

Evaluation of the Predictive Character of the Expiratory Inferior Vena Cava/Abdominal Aorta (eIVC/Ao) Index for Minimum Blood Pressure Following Spinal Anesthesia With 0.5% Hyperbaric Bupivacaine

Spinal anesthesia has many side effects, one of them being a drop in blood pressure (BP). Identifying predictive factors for this drop is a clear matter of concern. In this regard, the expiratory inferior vena cava/abdominal aorta (eIVC/Ao) index has already been spotted as such for doses of 0.5% hyperbaric bupivacaine greater than 12mg. Departing from the demonstrated correlation between this index and hypotension post-spinal anesthesia, our study aimed to (1) evaluate whether an eIVC/Ao index greater than 0.7, thus defining non-hypovolemic patients, can also predict minimal BP for doses inferior to 12mg and (2) identify other predictive factors for minimal BP post-spinal anesthesia. Lastly, we verified whether preoperative fasting induces hypovolemia.  This single-center prospective observational pilot study included 20 patients. The baseline measurements of BP, eIVC/Ao index, and fasting time were recorded at time T0'. Then spinal anesthesia was administered with 0.5% hyperbaric bupivacaine in doses inferior to 12 mg. The patients' systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and metameric levels were each recorded at times T5', T10', T15', and T20'.  The results indicated that baseline DBP was predictive of low DBP and minimum MAP, which reflect myocardial perfusion and systemic pressures, respectively. Therefore, it should trigger prophylaxis (spinal-lateralized, continuous, or lower dose) in patients with a low DBP baseline. Additionally, baseline SBP was predictive of minimum SBP, an independent risk factor for post-anesthetic hypotension if its baseline is less than 120 mmHg. Although female gender was linked to minimum SBP, other confounding factors (size, dose administered, and type of surgery related to gender) must also be considered. Moreover, a correlation was established between height and MAP in parturients. Hypotension was not recorded at local anesthetic (LA) doses between 8 and 12 mg and the doses administered were sufficient to achieve the metameric levels required for surgery (ether tests). Since 8 mg of 0.5% hyperbaric bupivacaine achieved the same level as 12 mg, lower doses of LA might prevent a significant drop in BP and its deleterious effects. Therefore, in the current cohort, the eIVC/Ao index was not predictive of minimum BP during spinal anesthesia with doses less than 12 mg of 0.5% hyperbaric bupivacaine. However, predictive factors for minimum BP included gender and baseline SBP (for minimum SBP), height and baseline DBP (for minimum MAP), and baseline DBP (for minimum DBP). Lastly, preoperative fasting did not cause hypovolemia.

Processing Ultrasound Scans of the Inferior Vena Cava: Techniques and Applications

The inferior vena cava (IVC) is the largest vein in the body. It returns deoxygenated blood to the heart from the tissues placed under the diaphragm. The size and dynamics of the IVC depend on the blood volume and right atrial pressure, which are important indicators of a patient's hydration and reflect possible pathological conditions. Ultrasound (US) assessment of the IVC is a promising technique for evaluating these conditions, because it is fast, non-invasive, inexpensive, and without side effects. However, the standard M-mode approach for measuring IVC diameter is prone to errors due to the vein movements during respiration. B-mode US produces two-dimensional images that better capture the IVC shape and size. In this review, we discuss the pros and cons of current IVC segmentation techniques for B-mode longitudinal and transverse views. We also explored several scenarios where automated IVC segmentation could improve medical diagnosis and prognosis.

Decreased inferior vena cava diameter as an early marker in postpartum hemorrhage

OBJECTIVES

To examine the association between inferior vena cava (IVC) diameter and postpartum blood loss and assess whether IVC diameter is a useful marker in the evaluation of intravascular volume status in women with postpartum hemorrhage (PPH).

METHODS

This was a prospective case-control study conducted in a university medical teaching center in Afula, Israel, between November 2018 and March 2020. The study cohort consisted of women with a singleton pregnancy who delivered vaginally at term. The PPH group included women diagnosed with PPH based on visually estimated blood loss of 1000 mL or more at the time of enrolment. Hemodynamically unstable women or women with major bleeding at the time of diagnosis were not included. The control group consisted of women with an uneventful fourth stage of labor. IVC diameter was measured using transabdominal ultrasonography during inspiration (IVCi diameter) and expiration (IVCe diameter), and the collapsibility index was calculated ((IVCe - IVCi)/IVCe × 100). The primary outcome was the percentage difference in IVC diameter and collapsibility index between the PPH group and controls. The performance of the IVC collapsibility index in the prediction of the need for blood transfusion in women with PPH was assessed. In order to demonstrate a difference of 20% with a power of 80% and alpha of 0.05, 108 women, at a ratio of 1:2 in the study and control groups, respectively, were needed.

RESULTS

Overall, 36 and 72 women were included in the final analysis in the PPH and control groups, respectively. IVCi and IVCe diameters were significantly smaller in the PPH group (0.93 ± 0.30 cm and 1.26 ± 0.32 cm, respectively) than in controls (1.42 ± 0.31 cm and 1.75 ± 0.28 cm, respectively) (P = 0.001 for both). The percentage reductions in IVCi and IVCe diameters in the PPH group compared with controls were 35.0% and 28.0%, respectively. IVC collapsibility index was increased significantly, by 42.9% (26.04 ± 8.67% vs 18.15 ± 5.07%; P = 0.001) in the PPH group compared with controls. IVC collapsibility index was a significant predictor of the need for blood transfusion and correctly predicted 81% of cases. Logistic regression analysis demonstrated that IVC collapsibility index was also a significant predictor of a drop in hemoglobin level of ≥ 2 g/dL (P = 0.001).

CONCLUSIONS

IVC diameter changes in response to postpartum blood loss. Measurement of IVC diameter using transabdominal ultrasonography is an objective and useful non-invasive method for the early evaluation of intravascular volume status in women with PPH and for the prediction of cases that might require blood transfusion. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Predictive Value of the Respiratory Variation in Inferior Vena Cava Diameter for Ventilated Children With Septic Shock

OBJECTIVES

This study aimed to investigate the predictive utility of respiratory variations of inferior vena cava diameters on fluid responsiveness in children with septic shock.

DESIGN

A prospective observational single-center study.

SETTING

A pediatric intensive care unit in a tertiary hospital in China.

PARTICIPANTS

Patients with sepsis shock who require invasive mechanical ventilation were recruited between 1 December 2017 and 1 November 2021.

INTERVENTIONS AND MEASUREMENTS

Volume expansion (VE) was induced by a 30-min infusion of 20 ml/kg of normal saline. Hemodynamics indexes were obtained through bedside transthoracic echocardiography (TTE) measurement and calculation.

RESULTS

A total of 86 patients were enrolled in this study, among them, 45 patients (52.3%) were considered to be non-responders (NR), with an increase in stroke volume variation (SVV) <15% after VE. Multivariate logistic analysis showed that ΔIVC (adjusted OR = 1.615, 95% CI 1.092-2.215, p = 0.012) was the significant predictor associated with the fluid responsiveness. The area under the ROC of ΔIVC was 0.922 (95% CI: 0.829-1.000, p < 0.01), and the cutoff value of ΔIVC used to predict fluid responsiveness was 28.5%, with a sensitivity and specificity of 95.4 and 68.5%, respectively.

CONCLUSIONS

The ΔIVC was found to have a potential value in predicting fluid responsiveness in mechanically ventilated children with septic shock.

The role of internal jugular vein Doppler ultrasonography in predicting hypovolemic shock in polytrauma patients

PURPOSE

The aim of this study was to evaluate the accuracy of internal jugular vein (IJV) Doppler ultrasonography in predicting hypovolemic shock in polytrauma patients.

METHODS

This prospective observational study was conducted on 75 multiple trauma patients (injury severity score >15) with a mean age of 33.00±9.57 years. IJV Doppler ultrasonography was performed in all patients with stable vital signs and a negative extended focused assessment with sonography for trauma. Jugular pulsatility index (JPI) values were calculated using the equation (Vmax-Vmin)/Vmax. Clinical and laboratory indices of hypovolemic shock were recorded at the time of admission. Patients were subsequently divided into those with hemorrhagic shock (n=36) and those without (n=39) based on the occurrence of hemorrhagic shock within 6 hours after admission. The results were compared between these groups.

RESULTS

IJV Doppler ultrasound parameters (JPI, Vmin, and Vmax-Vmin) showed significant differences between the two groups. The JPI values of patients with hemorrhagic shock were significantly lower than those in the control group (0.43±0.21 vs. 0.78±0.24, P<0.001). The sensitivity, specificity, and discriminant ability (area under the curve) of JPI in detecting hemorrhagic shock were 86.11%, 82.05%, and 0.853 (P<0.001), respectively.

CONCLUSION

IJV Doppler ultrasonography can reliably predict hemorrhagic shock in polytrauma patients with stable vital signs. Ultrasonography can be used in combination with clinical signs and laboratory findings to diagnose patients at risk of hypovolemic shock.

Sonographic Estimation Rather Than Quantification of Fluid Status Using Inferior Vena Cava and Other Major Vessel Parameters in a Non-Bleeding Fluid Loss and Centralization Model

Objective

A well-accepted step in emergency sonography is the estimation of a fluid deficit through Inferior Vena Cava (IVC) diameter variability with known cut-offs especially in bleeding. We sought to answer, whether a non-bleeding fluid deficit can be quantified through sonographic assessment of IVC diameter variability and related aortic parameters. Sport divers were used as human hypovolemic vasoconstriction models since immersion is known to cause relevant volume depletion through vasoconstriction and induced diuresis.

Materials and Methods

Forty-one sport divers performed 342 single and repetitive dives to account for intra- and interindividual variability and were assessed for inferior Vena Cava and neighboring aortic diameters as well as their cardiac/respiratory variations. Dive-related weight loss was measured together with sonographic vessel diameter changes inferior to the right atrium.

Results

Highest correlation with dive-related weight loss of max. 2.9 kg per an average 47 minutes dive was found with r=0.34 for the difference of IVC maximum diameter related to minimum Aortic diameter. Single or combined parameters, as well as Collapsibility Index, showed lower or no correlations. Vascular parameters were able to explain 7.5% of the variance of fluid losses, whereas interindividual effects explained 10%. The remaining 82.5% is of mixed intraindividual counterregulatory effects.

Conclusion

IVC diameter changes in immersion-induced hypovolemic centralization provides qualitative information on relevant fluid loss only. Confounding factors like inter and intraindividual variability prevent a sufficient correlation for useful quantification of the experienced non-bleeding fluid deficit in the clinical setting.

Point-of-care ultrasound to assess volume status and pulmonary oedema in malaria patients

PURPOSE

Fluid management is challenging in malaria patients given the risks associated with intravascular fluid depletion and iatrogenic fluid overload leading to pulmonary oedema. Given the limitations of the physical examination in guiding fluid therapy, we evaluated point-of-care ultrasound (POCUS) of the inferior vena cava (IVC) and lungs as a novel tool to assess volume status and detect early oedema in malaria patients.

METHODS

To assess the correlation between IVC and lung ultrasound (LUS) indices and clinical signs of hypovolaemia and pulmonary oedema, respectively, concurrent clinical and sonographic examinations were performed in an observational study of 48 malaria patients and 62 healthy participants across age groups in Gabon.

RESULTS

IVC collapsibility index (CI) ≥ 50% on enrolment reflecting intravascular fluid depletion was associated with an increased number of clinical signs of hypovolaemia in severe and uncomplicated malaria. With exception of dry mucous membranes, IVC-CI correlated with most clinical signs of hypovolaemia, most notably sunken eyes (r = 0.35, p = 0.0001) and prolonged capillary refill (r = 0.35, p = 0.001). IVC-to-aorta ratio ≤ 0.8 was not associated with any clinical signs of hypovolaemia on enrolment. Among malaria patients, a B-pattern on enrolment reflecting interstitial fluid was associated with dyspnoea (p = 0.0003), crepitations and SpO₂ ≤ 94% (both p < 0.0001), but not tachypnoea (p = 0.069). Severe malaria patients had increased IVC-CI (p < 0.0001) and more B-patterns (p = 0.004) on enrolment relative to uncomplicated malaria and controls.

CONCLUSION

In malaria patients, POCUS of the IVC and lungs may improve the assessment of volume status and detect early oedema, which could help to manage fluids in these patients.

Central venous pressure, global end-diastolic index, and the inferior vena cava collapsibility/distensibility indices to estimate intravascular volume status in critically ill children: A pilot study

BACKGROUND

The assessment of the volume status in critically ill paediatric patients in intensive care units is vitally important for fluid therapy management. The most commonly used parameter for detecting volume status is still central venous pressure (CVP); however, in recent years, various kinds of methods and devices are being used for volume assessment in intensive care units.

OBJECTIVES

We aimed to evaluate the relationship between CVP, the global end-diastolic index (GEDI), and ultrasound measurements of the collapsibility and distensibility indices of the inferior vena cava (IVC) in paediatric patients undergoing Pulse index Contour Cardiac Output (PiCCO) monitoring.

METHODS

Fifteen patients receiving PiCCO monitoring were prospectively included in the study. Forty-nine PiCCO measurements were evaluated, and simultaneous CVP values were noted. After each measurement, IVC collapsibility (in spontaneously breathing patients) and distensibility (in mechanically ventilated patients) indices were measured with bedside ultrasound.

RESULTS

The mean age was 93.2 ± 61.3 months. Significant and negative correlations of the GEDI were found with the IVC collapsibility index (in spontaneously breathing patients) and the IVC distensibility index (in mechanically ventilated patients) (r = -0.502, p < 0.001; r = -0.522, p = 0.001, respectively). A significant and weakly positive correlation was found between the GEDI and CVP (r = 0.346, p = 0.015), and a significant and negative correlation was found between the IVC collapsibility index and CVP (r = -0.482, p = 0.03). The correlation between the IVC distensibility index and CVP was significant and negative (r = -0.412, p = 0.04).

CONCLUSION

The use of PiCCO as an advanced haemodynamic monitoring method and the use of bedside ultrasound as a noninvasive method are useful to evaluate the volume status in critically ill paediatric patients in intensive care. These methods will gradually come to the fore in paediatric intensive care.

Ultrasonographic inferior vena cava collapsibility and distensibility indices for detecting the volume status of critically ill pediatric patients

Especially in recent years, the use of point-of-care ultrasound by non-radiologist clinicians has become widespread. Point-of-care ultrasound provides rapid responses to the problems of critically ill patients at the bedside. This technique has many important advantages, including being non-invasive, cheap, repeatable, painless, and radiation-free. Numerous studies have revealed the most important clinical benefits of point-of-care ultrasound use by pediatric intensive care providers. The inferior vena cava is a vessel that is highly sensitive to fluid changes. The inferior vena cava diameter can be measured by a point-of-care ultrasound, and represents a critical parameter in assessing the patient’s fluid status. The inferior vena cava collapsibility index (in spontaneously breathing patients) and the inferior vena cava distensibility index (in mechanically ventilated patients) are calculated by determined formulas by using maximum and minimum diameters of the inferior vena cava. The indices are important guides for pediatric intensive care providers for managing their patients’ fluid treatment. Although some authors claim it is not a reliable method, the technique is coming to fore in intensive care units day by day, and has an increasing trend among pediatric intensive care specialists. Here, we aim to give detailed information on the ultrasonographic inferior vena cava diameter measurement methods, and calculations of the inferior vena cava collapsibility index and inferior vena cava distensibility index, and emphasize the importance of a noninvasive, bedside, and objective method of detecting the volume status of critically ill patients for pediatric intensive care specialists according to the published literature.

[Index from Diameter of Inferior Vena Cava and Abdominal Aorta of Newborns - A Relevant Method for Evaluation of Hypovolemia]

Hypovolemia is one of the important problems in sick neonates. Ultrasound is a safe, noninvasive diagnostic tool for the assessment of volume status. For that reason, the aim of the study was to determine normal values of the diameter of inferior vena cava (IVC), abdominal aorta (Ao) and the index IVC/Ao.

PATIENTS AND METHODS

97 healthy, term neonates were included in the study and investigated at first and third day of life. The diameter of IVC, Ao was measured and the index from IVC/Ao was estimated. Using statistics mean and median values of the parameters and correlations to birth weight were determined.

RESULTS

Diameter of Ao at first day was 6.1 (+/-0.6) mm and at third day 6.2 (+/-0.6) mm, of IVC at first day was 2.5 (+/-0.5) and at third day 2.61 (+/-0.5). The Index from diameters of IVC/Ao was evaluated at day 1 as 0.4 (+/-0.1) and day 3 as 0.4 (+/-0.1). We found a positive correlation to the birth weight. We identified a significant difference of the index in SGA and LGA - neonates (0.36 vs 0.47). Despite a significant reduced weight from first to third day in the neonates, we determined no influence on the diameter of IVC, Ao and the index IVC/Ao.

CONCLUSION

We determined normal values of diameter of IVC and Ao and the Index of IVC/Ao. It is our opinion, that it is possible to assess the intravascular volume using the index. The importance of the index can be underlined by the results in SGA-neonates. More research is needed to understand some points of the pathophysiology in SGA.

Effect of Changes in Intravascular Volume on Inferior Vena Cava and Aorta Diameters and the Caval/Aorta Index in Healthy Volunteers

OBJECTIVES

Although inferior vena cava diameter (IVCD) measurement can be useful as a noninvasive method for monitoring the volume status, the benefit of abdominal aorta diameter (AAD) measurement is unclear. The purpose of this study was to determine the value of the combined use of the IVCD and AAD in blood loss monitoring.

METHODS

This prospective observational study was conducted at the blood donor center of a training and research hospital. Standard blood donation criteria were followed during volunteer enrollment. Vital signs and ultrasound IVCD and AAD measurements were obtained before and after blood donation and after fluid resuscitation with 500 mL of 0.9% sodium chloride. Measurements before and after blood donation and after fluid resuscitation were compared by the paired t and Wilcoxon matched-pair tests.

RESULTS

Thirty-nine volunteers were included in the study. With 500 mL of blood loss, percent changes in the shock index (SI; mean ± SD, 7% ± 6%), IVCD (6% ± 2%), and caval/aorta index (IVCD/AAD; 6.1% ± 3%) were similar and were higher (P < .001 for all parameters) than the changes in the pulse rate (3% ± 4%), AAD (0.5% ± 1.5%), systolic blood pressure (3% ± 4%), and diastolic blood pressure (2% ± 7%). Although IVCD and SI values changed significantly (P < .001 for both) after 500 mL of 0.9% sodium chloride resuscitation, no significant change was observed in the IVCD/AAD (P = .059).

CONCLUSIONS

The IVCD/AAD, SI, and IVCD may have similar success rates in diagnosing early blood loss. Additionally, the SI and IVCD may be superior to the IVCD/AAD in bleeding patients requiring simultaneous fluid resuscitation.

Pre-operative ultrasonographic evaluation of inferior vena cava collapsibility index and caval aorta index as new predictors for hypotension after induction of spinal anaesthesia: A prospective observational study

BACKGROUND

Hypotension after spinal anaesthesia is a common side effect that may be harmful. Patients' susceptibility to intra-operative hypotension can be affected by many pre-operative factors.

OBJECTIVES

The current study aimed to evaluate the efficacy of both pre-operative inferior vena cava collapsibility index (IVCCI) and inferior vena cava to aorta diameter (IVC : Ao) index for predicting postspinal anaesthesia hypotension (PSAH).

DESIGN

Prospective observational blinded study.

SETTING

Operating room from June 2017 to February 2018.

PATIENTS

One hundred adult patients of both sexes, American Society of Anesthesiologists' physical status 1 or 2 scheduled for elective surgery under spinal anaesthesia were included in this study.

INTERVENTIONS

Patients received spinal anaesthesia performed at the level of L3 to 4 or L4 to 5 intervertebral space with the patient in the sitting position then placed in the supine position immediately after neuraxial block and kept supine throughout the study period (30 min). IVCCI and IVC : Ao index were assessed pre-operatively. Baseline noninvasive blood pressure was recorded before administration of spinal anaesthesia then every minute after spinal blockade for 30 min.

MAIN OUTCOME MEASURES

The primary outcome was to evaluate the predictive values of both IVCCI and IVC : Ao index for detecting PSAH and the secondary outcomes were to compare the predictive values of both IVCCI and IVC : Ao index and to detect other clinical predictors for PSAH using logistic regression analysis.

RESULTS

Forty-five patients developed PSAH (45%). IVCCI was significantly higher in patients who developed PSAH than in patients who did not, while IVC : Ao index was significantly lower in patients who developed PSAH than in patients who did not. Hypotension after induction of spinal anaesthesia was defined as an absolute value of SBP less than 90 mmHg, a decrease in SBP more than 30% of the baseline value or an absolute value of arterial blood pressure less than 60 mmHg. Logistic regression analysis revealed that IVCCI and IVC : Ao index were good predictors of the occurrence of PSAH. Receiver operating characteristic curve analysis showed that IVC : Ao index had a sensitivity of 96%, a specificity of 88%, and an accuracy of 95% to predict PSAH at a cut-off point less than 1.2. IVCCI had a sensitivity of 84%, a specificity of 77%, and an accuracy of 84% to predict PSAH at a cut-off point more than 44.7%.

CONCLUSION

Pre-operative IVCCI and IVC : Ao index are good predictors of the occurrence of PSAH. However, IVC : Ao index is a more powerful predictor than IVCCI.

Internal Jugular Vein Waveform; A New Insight to Detect Early Stage of Hemorrhagic Shock

OBJECTIVE

To evaluate the accuracy of internal jugular vein waveform to detect early stage of hemorrhagic shock.

METHODS

Forty-three volunteers enrolled in our study between November and December 2018. After blood donation of 450cc, the blood donors in the case group underwent color Doppler sonography of internal Jugular Vein. Besides, the clinical and laboratory indicators of shock were evaluated. The same clinical, laboratory and sonographic data was also obtained from the volunteers in the control group, then Chi-square and Student t-test were applied to make comparison between mentioned groups.

RESULTS

After excluding five volunteers, eighteen subjects were included in the blood donor group (mean of age: 35.81±8.05) and 20 healthy volunteers enrolled in the control group (mean of age: 34.95± 6.86). The Jugular pulsatility index was significantly smaller in the case group (0.47 ± 0.27 vs. 0.77 ± 0.52). The jugular pulsatility index above 0.91 excluded blood loss (sensitivity=100%). The combination of clinical, laboratory and sonographic data were also represented as two other indices; Jugular Pulsatility-Shock index and Jugular Pulsatility-Shock-Base Deficit index (JPSBDI). These indices were also accurate enough to detect early blood loss (p=0.011 and <0.001, respectively). JPSBDI below 0.38 was highly accurate to rule out blood loss. (Area under the curve: 0.868, sensitivity=95% and specificity=76.47%).

CONCLUSION

The internal Jugular vein waveform is accurate to detect early stages of shock. The combination of clinical, laboratory and sonographic data is more promising than each of them, separately.

Inferior vena cava, abdominal aorta, and IVC-to-aorta ratio in healthy Caucasian children: Ultrasound Z-scores according to BSA and age

The pediatric ultrasound measurement of the inferior vena cava (IVC) and aorta (AO) with the study of the collapsibility index (CI) and of IVC-to-AO ratio (IVC/AO) can provide clinicians in the acute care setting with information on abnormal volume status but one of the major limitations is a lack of reference normal values by body surface area (BSA) and age. The aim of this study was to provide reference ranges for the sonographic measurement of IVC, AO, and IVC/AO ratio in healthy Caucasian Italian children.

METHODS

We enrolled prospectively 516 healthy Caucasian Italian children aged between 1 month and 16 years. Echocardiographic IVC and AO diameters were collected and presented separately for children aged ≤1 year and for children aged over 1 year. For children >1 year we categorized subjects into 3 years classes. CI and IVC/AO for the systolic aortic diameter were then calculated. For children over 1 year, age reference ranges were age-related or BSA-related; for children of ≤1 year, reference ranges were determined with their 90% confidence intervals regardless of age and of BSA.

RESULTS

Tables and charts with reference ranges for all the echocardiographic measurements are presented for children aged >1 year according to age and BSA. The equations to obtain percentile and Z-score for each echocardiographic measurement are provided. The reference ranges for children aged ≤1 year are shown considering the small 90% confidence intervals for upper and lower limits. CI was 30% (SD 17%) in children >1 year and 36% (SD 16%) in children <1 year. IVC/AOs showed age-dependent values from 0.83 (SD 0.20) age <1 year to 1.22 (SD 0.31) in older subjects.

CONCLUSIONS

We report reliable reference ranges for echocardiographic measurement of IVC, AO, CI, and IVC/AO for a Caucasian Italian healthy pediatric population.

Evaluation of volume status in a prehospital setting by ultrasonographic measurement of inferior vena cava and aorta diameters

Objectives

The aim of this study was to evaluate the utility of ultrasonographic measurement of the diameter of the inferior vena cava (IVCD) and abdominal aorta (AAD) for assessing volume status.

Material and methods

This was a prospective, observational study. A total of 23 volunteers participated in the study. Each participant was selected randomly. All participants completed the 2016 Kaunas Marathon. Participants filed out a brief survey about their fluid intake (in standardised glasses) in the 24 h before the race and during the race. Participants underwent ultrasound measurements 10-40 min before the start of the race and 3-15 min after finishing the race. To visualize respiratory variation, M-mode was used, with the beam crossing the IVCD 2 cm from the right atrium. The AAD was measured 1 cm above the celiac trunk. IVCD in expiration (IVCDexp)/AAD was calculated by dividing the value of IVCDexp by the value of AAD. The findings were compared with difference in body mass index.

Results

The mean weight lost after the marathon was 2.93 kg (p < 0.001). Mean IVCD in inspiration (IVCDins) after the run was lower by 0.39 cm (p < 0.001) then before the run. Mean IVCDexp/AAD after the run was 0.24 cm lower than before the run (p = 0.03). Before and after the marathon, there was a statistically significant negative correlation in weight difference, with mean IVCDexp difference (p = 0.047). There was no statistically significant difference in caval index before and after running.

Conclusion

Ultrasonographic assessment of IVCDexp could be useful in the evaluation of volume status.

Ultrasound measurements of the caudal vena cava before and after blood donation in 9 greyhound dogs

This prospective study evaluated variation in the diameter of the caudal vena cava (DCdVC) as a marker of change in intravascular volume before and after blood donation in greyhound dogs. A preliminary study determined that the DCdVC increased with body weight. Nine greyhound blood donors had ultrasonographic images acquired of the maximum and minimum DCdVCs in transverse and sagittal orientations and sagittal aortic diameter (AoD) before and after blood donation. The collapsibility index = [(maximal mean transverse DCdVC - minimal mean transverse DCdVC)/maximal mean transverse DCdVC] and transverse DCdVC:AoD ratio were calculated for each dog. In the greyhounds, the changes in mean minimal and maximal transverse DCdVC (0.69 and 0.84 mm, respectively) and sagittal mean maximal DCdVC (0.9 mm) and collapsibility index (0.018) were significantly different (P < 0.05) before and after blood donation. While statistically significant, the magnitude of DCdVC change found in this limited number of greyhound dogs with 8% intravascular volume loss during blood donation was small. This magnitude of change is likely indistinguishable in clinical patients.