Dynamic behavior of venous collapsibility and central venous pressure during standardized crystalloid bolus: A prospective, observational, pilot study

Comparison of inferior vena cava collapsibility and central venous pressure in assessing volume status in shocked patients

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An accurate diagnosis of shock state can be challenging, particularly in low-income countries, such as African countries, because physical signs of hypovolaemic, distributive, cardiogenic, and obstructive shock frequently overlap.

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Low-income countries therefore require easy and noninvasive methods, such as ultrasound devices.

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This study aims to provide an accurate estimation of intravascular volume status using bedside noninvasive methods as an essential part of the management of shocked patients.

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We discovered that the inferior vena cava collapsibility index (IVC-ci) could be a good tool with moderate reliability for detecting fluid responsiveness because it is a less invasive and fast method.

Introduction

Determination of intravascular volume status in patients admitted to the emergency centre is critical. Physical signs of hypovolaemic, distributive, cardiogenic, and obstructive shock frequently overlap, making an accurate diagnosis of shock state difficult. This is problematic because fluid loading is considered the first step in haemodynamically unstable patients’ resuscitation. Yet, multiple studies have shown that only approximately 50% of haemodynamically unstable patients in the intensive care unit and operating theatre respond to a fluid challenge. This study aims to provide an accurate estimation of intravascular volume status using bedside noninvasive methods as an essential part of the assessment of volume status in shocked patients.

Methodology

This is a cross-sectional analytical study conducted on 102 shocked patients presented to the emergency centre. IV fluid boluses were standardized to be administered at 500 mL every 30 min over 120 min, as clinically indicated. Concurrent measurements of inferior vena cava collapsibility index (IVC-ci) were performed shortly before the initiation of IV bolus (i.e., time 0), and then at 30, 90, and 120 min, we measured both venous collapsibility index (CI) and central venous pressure (CVP). At each session, we recorded patient demographics, fluid responsiveness, and vital sign assessments.

Results

We discovered that IVC-ci at cut-off point 40 has a sensitivity of 93.3% and specificity of 70.7% with an AUC of 0.908 and a good 95% CI (0.84–0.975), implying that IVC-ci of 40% or higher can indicate fluid responsiveness in shocked patients. CVP, despite having a good sensitivity of 88.6%, high specificity of 100%, and a significant p-value, is not a reliable detector of fluid responsiveness due to its small AUC value and low 95% CI.

Conclusion

IVC-ci could be a good tool with moderate reliability for detecting fluid responsiveness because it is a less invasive and fast method.

Assessment of hemodynamic response to fluid resuscitation of patients with intra-abdominal sepsis in low- and middle-income countries

BACKGROUND

Patients with intra-abdominal infections need to achieve adequate hemodynamic status before being taken to the operating room. Multiple parameters (urinary output [UOP], vital signs, inferior vena cava collapsibility index, and central venous pressure) may be used to assess hemodynamic response to fluid resuscitation, but the options are few in limited-resource settings. This study aimed at assessing if a bedside-performed ultrasound to assess the inferior vena cava collapsibility index is superior to UOP in assessing hemodynamic response to fluid resuscitation.

METHODS

All adult patients presenting to a tertiary referral hospital in the capital city of Rwanda with intra-abdominal infection requiring intravenous fluid (IVF) resuscitation before operation were included in this study. Before IVF administration, the baseline inferior vena cava collapsibility index (IVC-CI) and vital parameters were recorded. After initiation of IVF resuscitation, serial measurements of IVC-CI and UOP were recorded every 2 h until the decision was made to take the patient to the operating room.

RESULTS

Twenty-four patients were enrolled. The mean duration of symptoms was 4.7 days. Four patients (16%) had altered mental status as a presenting symptom. Half of all patients had generalized peritonitis due to gangrenous bowel as the primary diagnosis (n = 12). The mean difference between time of hemodynamic response based on IVC-CI versus UOP was 2 h (P < 0.001).

CONCLUSIONS

Measurement of the IVC-CI can provide early detection of hemodynamic response to fluid therapy in patients with intra-abdominal infection with spontaneous breathing compared to UOP. Future research should utilize this parameter in the preoperative management of hemodynamically unstable patients.

Keys to successful organ procurement: An experience-based review of clinical practices at a high-performing health-care organization

Organ procurement (OP) from donors after brain death and circulatory death represents the primary source of transplanted organs. Despite favorable laws and regulations, OP continues to face challenges for a number of reasons, including institutional, personal, and societal barriers. This focused review presents some of the key components of a successful OP program at a large, high-performing regional health network. This review focuses on effective team approaches, aggressive resuscitative strategies, optimal communication, family support, and community outreach efforts.

Correlations between pulmonary artery pressures and inferior vena cava collapsibility in critically ill surgical patients: An exploratory study

INTRODUCTION

As pulmonary artery catheter (PAC) use declines, search continues for reliable and readily accessible minimally invasive hemodynamic monitoring alternatives. Although the correlation between inferior vena cava collapsibility index (IVC-CI) and central venous pressures (CVP) has been described previously, little information exists regarding the relationship between IVC-CI and pulmonary artery pressures (PAPs). The goal of this study is to bridge this important knowledge gap. We hypothesized that there would be an inverse correlation between IVC-CI and PAPs.

METHODS

A post hoc analysis of prospectively collected hemodynamic data was performed, examining correlations between IVC-CI and PAPs in a convenience sample of adult Surgical Intensive Care Unit patients. Concurrent measurements of IVC-CI and pulmonary arterial systolic (PAS), pulmonary arterial diastolic (PAD), and pulmonary arterial mean (PAM) pressures were performed. IVC-CI was calculated as ([IVCmax - IVCmin]/IVCmax) × 100%. Vena cava measurements were obtained by ultrasound-credentialed providers. For the purpose of correlative analysis, PAP measurements (PAS, PAD, and PAM) were grouped by terciles while the IVC-CI spectrum was divided into thirds (<33, 33-65, ≥66).

RESULTS

Data from 34 patients (12 women, 22 men, with median age of 59.5 years) were analyzed. Median Acute Physiologic Assessment and Chronic Health Evaluation II score was 9. A total of 76 measurement pairs were recorded, with 57% (43/76) obtained in mechanically ventilated patients. Correlations between IVC-CI and PAS (rs = -0.334), PAD (rs = -0.305), and PAM (rs = -0.329) were poor. Correlations were higher between CVP and PAS (R2 = 0.61), PAD (R2 = 0.68), and PAM (R2 = 0.70). High IVC-CI values (≥66%) consistently correlated with measurements in the lowest PAP ranges. Across all PAP groups (PAS, PAD, and PAM), there were no differences between the mean measurement values for the lower and middle IVC-CI ranges (0%-65%). However, all three groups had significantly lower mean measurement values for the ≥66% IVC-CI group.

CONCLUSIONS

Low PAS, PAD, and PAM measurements show a reasonable correlation with high IVC-CI (≥66%). These findings are consistent with previous descriptions of the relationship between IVC-CI and CVP. Additional research in this area is warranted to better describe the hemodynamic relationship between IVC-CI and PAPs, with the goal of further reduction in the reliance on the use of PACs.