Handcarried ultrasound measurement of the inferior vena cava for assessment of intravascular volume status in the outpatient hemodialysis clinic

Prevention of hypotension after induction of general anesthesia using point-of-care ultrasound to guide fluid management: a randomized controlled trial

PURPOSE

Hypotension after induction of general anesthesia (GAIH) is common and is associated with postoperative complications including increased mortality. Collapsibility of the inferior vena cava (IVC) has good performance in predicting GAIH; however, there is limited evidence whether a preoperative fluid bolus in patients with a collapsible IVC can prevent this drop in blood pressure.

METHODS

We conducted a single-centre randomized controlled trial with adult patients scheduled to undergo elective noncardiac surgery under general anesthesia (GA). Patients underwent a preoperative point-of-care ultrasound scan (POCUS) to identify those with a collapsible IVC (IVC collapsibility index ≥ 43%). Individuals with a collapsible IVC were randomized to receive a preoperative 500 mL fluid bolus or routine care (control group). Surgical and anesthesia teams were blinded to the results of the scan and group allocation. Hypotension after induction of GA was defined as the use of vasopressors/inotropes or a decrease in mean arterial pressure < 65 mm Hg or > 25% from baseline within 20 min of induction of GA.

RESULTS

Forty patients (20 in each group) were included. The rate of hypotension after induction of GA was significantly reduced in those receiving preoperative fluids (9/20, 45% vs 17/20, 85%; relative risk, 0.53; 95% confidence interval, 0.32 to 0.89; P = 0.02). The mean (standard deviation) time to complete POCUS was 4 (2) min, and the duration of fluid bolus administration was 14 (5) min. Neither surgical delays nor adverse events occurred as a result of the study intervention.

CONCLUSION

A preoperative fluid bolus in patients with a collapsible IVC reduced the incidence of GAIH without associated adverse effects.

STUDY REGISTRATION

ClinicalTrials.gov (NCT05424510); first submitted 15 June 2022.

Sonographic findings using the SAFE-A protocol in pre- and post-hemodialysis patients

BACKGROUND

Accurate assessment of relative intravascular volume is one of the cornerstones for the proper management of hospitalized patients requiring hemodialysis. Currently, the use of dynamic parameters such as bedside ultrasonography is recommended to support the assessment of the intravascular volume profile. This study aimed to prospectively evaluate findings of sonographic assessment of intravascular volume estimate (SAFE-A) protocol among hemodialysis inpatients with end-stage renal disease, before and after the hemodialysis sessions, and correlate these findings with the net ultrafiltrate (UFNET).

RESULTS

A positive correlation was found between the negative variation of 1 point in the score of the SAFE-A protocol with the withdrawal of 426.73 mL of net ultrafiltrate.

CONCLUSIONS

There was a strong correlation between the score of the SAFE-A protocol and the net ultrafiltrate. Therefore, this study concludes that the application of the SAFE-A protocol in dialysis patients demonstrates a correlation between the suggested score and volume status, consistent with findings from the original study conducted in a distinct population.

Inferior vena cava ultrasound to predict hypotension after general anesthesia induction: a systematic review and meta-analysis of observational studies

PURPOSE

Hypotension after induction of general anesthesia is common and is associated with significant adverse events. Identification of patients at high risk can inform the use of preoperative mitigation strategies. We conducted a systematic review and meta-analysis to assess the diagnostic accuracy of the inferior vena cava collapsibility index (IVC-CI) and maximal diameter (dIVCmax) in predicting postinduction hypotension and to identify their predictive performance across different threshold ranges.

METHODS

We searched MEDLINE, PubMed®, and Embase from inception to March 2023 for prospective observational studies exploring the performance of IVC-CI and dIVCmax in predicting postinduction hypotension in adults presenting for elective surgery under general anesthesia. We excluded studies reporting on IVC parameters predicting postinduction hypotension in the obstetric patient population or exclusively in patients with obesity. Trials screening and data extraction were conducted independently. We performed meta-analyses to identify the performance of IVC parameters in predicting postinduction hypotension, followed by subgroup analyses that sought the IVC-CI range with the highest hierarchical summary receiver-operating characteristic area under the curve (HSROC-AUC). We used a bivariate random effects model to calculate summary estimates. We evaluated study quality using Newcastle-Ottawa scores and certainty of evidence using the GRADE framework.

RESULTS

We included 14 studies involving 1,166 patients. Pooled sensitivity and specificity of the IVC-CI to predict postinduction hypotension was 0.68 (95% confidence interval [CI], 0.55 to 0.79; coverage probability, 0.91) and 0.78 (95% CI, 0.69 to 0.85; coverage probability, 0.9), respectively, with an HSROC-AUC of 0.80 (95% CI, 0.68 to 0.85, high quality of evidence). An IVC-CI threshold range of 40-45% had an HSROC-AUC of 0.86 (95% CI, 0.69 to 0.93, high quality of evidence).

CONCLUSIONS

Preoperative IVC-CI is a strong predictor of postinduction hypotension. We recommend that future studies use an IVC-CI threshold of 40-45% (low certainty of evidence). Future studies are needed to establish whether ultrasound-guided preoperative optimization improves outcomes in high-risk patients.

STUDY REGISTRATION

PROSPERO ( CRD42022316140 ); first submitted 10 March 2022.

PICC insertion and veins of the arm size variation during dialysis treatment: A prospective observational study

BACKGROUND

Peripherally Inserted Central Catheters play an increasingly important role in Central Venous Access Devices. However, the use of these devices should be carefully considered in specific situations such as central catheterisation in patients with chronic kidney disease. When evaluating the feasibility of placement for a patient undergoing dialysis, the relationship between changes in circulating volume before and after dialysis treatment, and potential variations in the size of deep veins in the upper limbs, should be considered.

MATERIALS

Upper limb veins, specifically the basilic or brachial veins, were identified and measured before and after dialysis treatment. Patient data and weight loss data during dialysis treatment were also collected. Linear regression analysis was performed to assess the correlation between the variables.

RESULTS

The average variation in vein size for the entire sample was +0.17 ± 0.43 mm. The mean volume removed was 2.2 ± 0.8 l. In subgroup 1 (fluid volume loss <2000 ml), the population experienced a decrease in the measured vein size after dialysis. In subgroup 2 (fluid volume loss ⩾2000 ml), the population experienced an increase in the measured vein size after dialysis.

CONCLUSIONS

Upper arm vascular access placement in dialysed patients with fluid removal of less than 2000 ml should be performed after the dialysis session. Conversely, in dialysed patients with fluid removal of more than 2000 ml, where a significant increase in vein size was observed, vascular access placement should be performed before the dialysis session when the veins are smaller. Additionally, it should be noted that in patients with chronic kidney disease, the venous system of the upper limbs should be preserved as much as possible to prevent thrombosis and stenosis in potential arteriovenous fistula creation.

Implementing a 3 year, longitudinal point of care ultrasound curriculum in an internal medicine residency program

PURPOSE

Point-of-care ultrasound (POCUS) is highly utilized in the critical care setting. There is also growing evidence supporting use of POCUS by internal medicine (IM) physicians as an extension of traditional physical diagnostic skills. As part of the newly formed curriculum at our residency program, we performed pre and post curriculum assessment of the residents' ability to acquire focused cardiac, lung, pleural, abdominal and vascular images.

METHODS

The POCUS instruction was delivered as a combination of pre-workshop self-study learning materials (monthly textbook chapters, online modules etc.), with short didactic sessions, and hands-on-scanning of healthy, male volunteers at 10-week intervals.

RESULTS

A total of 62 residents (23 Post-Graduate Year 1 (PGY), 24 PGY2, 15 PGY3) participated in the year-long curriculum. When pretest and post test data were analyzed at the end of the curriculum, we calculated the odds ratio for acquiring the correct image (score of 1) vs partial/incorrect acquisition (scores of 2 and 3). Significant differences were found in acquisition of most views including para-sternal short (OR 7.7, 95% CI 2.86-20.74, p < 0.001), Inferior vena cava (IVC) (OR 5.05, 95% CI 1.91-13.35, p = 0.001) and bladder (OR 5.06, 95% CI 1.76-14.55, p = 0.003). Non-significant differences were found in acquisition of apical 4 chamber, pl (A-Line) and internal jugular vein (IJV).

CONCLUSION

We found that the implementation of a longitudinal POCUS curriculum resulted in significant improvement in image acquisition for many common bedside ultrasound views. Future directions include advancing our bedside echocardiography curriculum for upper-level residents to include quantitative left ventricular and right ventricular function analysis, and including more case based pathologic image review.

Hydralazine combined with conventional therapy improved outcomes in severe systolic dysfunction and mitral regurgitation

AIMS

Patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF) accompanied by significant mitral regurgitation (MR) had poor outcome. Several vasodilator trials showed neutral results. We aimed to investigate the effect of early up-titration of hydralazine combined with conventional treatment in acute HF with severe systolic dysfunction and significant MR.

METHODS AND RESULTS

The study was open-labelled, one-to-one ratio randomized designed. Consecutively hospitalized patients with decompensated HF symptoms, LVEF < 35%, and MR more than moderate severity were enrolled after exclusion. All participants with inadequate preload should have intake promotion with/without fluid supply. Patients receiving evidence-based medications (EBMs) as conventional treatment served as the control. Hydralazine + conventional treatment group received up-titration of hydralazine at Days 1-5 of the index admission combined with EBMs and throughout the course of follow-up. The endpoints included cardiovascular (CV) death and HF rehospitalization. Totally, 408 patients were enrolled (203 in conventional treatment and 205 in hydralazine + conventional treatment). The mean follow-up period was 3.5 years. The mean dose of hydralazine was 191 mg at index admission and 264 mg at study end in hydralazine + conventional treatment group. Both groups did not significantly differ in prescription rates and dosages of EBMs (all P > 0.05) at study end. Side effects did not differ between the two groups. Finally, 51% (104 out of 203 cases) reached endpoints in conventional group and 34.6% (71 out of 205 cases) in hydralazine + conventional treatment group, which had a significant reduction in CV events (hazard ratio 0.613, 95% confidence interval 0.427-0.877, P < 0.001). In-hospital death during the index admission was significantly higher in conventional group (5.4% vs. 0.5%, respectively; P = 0.001).

CONCLUSIONS

When administered without inadequate preload, combining early up-titration of hydralazine with EBMs improves outcome in patients with severe systolic dysfunction and significant MR, and it is safe and well tolerated.

Impact of an enhanced focused cardiac ultrasound on treatment changes in a population of internal medicine patients

BACKGROUND

Hospitalized patients with acute shortness of breath (SOB) could benefit from an enhanced focused cardiac ultrasound (eFoCUS) with Doppler measurements to reassess treatment and diagnosis.

METHODS

This was a retrospective observational study performed in a medical ward. Included patients were those hospitalized for acute SOB. The objectives were to assess therapeutic and diagnosis changes associated with eFoCUS. The primary endpoint of the analysis was a composite of introduction or discontinuation of diuretics, antibiotics or anticoagulation following eFoCUS.

RESULTS

Between January 2018 and July 2021, 119 patients were included, 67 women and 52 men, mean age 84 ± 11 years old. The eFoCUS was performed within a median time of 55 h (1st-3rd IQ: 21-107) following hospital admission. Overall, eFoCUS was associated with a change in diagnostic in 40 patients (34% [CI 95%: 25%-43%], p < 10-4 ) and a change in treatment in 53 patients (45% [CI 95%: 35%-54%], p < 10-4 ). Diuretics were prescribed in 94 patients before eFoCUS and in 56 after (p = 10-4 ), antibiotics in 34 before and 27 after and anticoagulation in 30 before and 40 after.

CONCLUSION

eFoCUS was associated with both therapeutic and diagnostic changes in patients with SOB. Such results should be confirmed in multicentric prospective studies.

Coronary sinus diameter to estimate congestion and predict survival

Background

Congestion predicts a poor prognosis, but its assessment is challenging in clinical practice and requires a multiparametric approach. We investigated if the coronary sinus (CS) diameter can predict mortality in a human model of rapid fluid unloading.

Methods

We measured by echocardiography the CS, and the inferior vena cava (IVC) for comparison, in 60 patients with end-stage chronic kidney disease (ESKD) immediately before and after hemodialysis (HD; age 76 [57-81] years, 40% female, left ventricular ejection fraction 57 [53-56]%). Patients were prospectively followed up for all-cause mortality.

Results

HD-induced decongestion decreased the maximum diameters of both CS and IVC (p ≤ 0.001 for all). The maximum diameter of the CS (CSmax) was as accurate as the IVC maximum diameter and collapsibility for the identification of congestion, defined as pre-hemodialysis status (AUROC CSmax = 0.902 vs IVC = 0.895, p = n.s.). A CSmax diameter after hemodialysis > 9 mm predicted all-cause mortality at 12 months (Log-rank Chi square = 11.49, p < 0.001).

Conclusions

A persistently dilated CS after hemodialysis is a marker of residual congestion and predicts death at one year in high-risk ESKD patients.

Proceedings of the 2022 UAB CRRT Academy: Non-Invasive Hemodynamic Monitoring to Guide Fluid Removal with CRRT and Proliferation of Extracorporeal Blood Purification Devices

In 2022, we celebrated the 15th anniversary of the University of Alabama at Birmingham (UAB) Continuous Renal Replacement Therapy (CRRT) Academy, a 2-day conference attended yearly by an international audience of over 100 nephrology, critical care, and multidisciplinary trainees and practitioners. This year, we introduce the proceedings of the UAB CRRT Academy, a yearly review of select emerging topics in the field of critical care nephrology that feature prominently in the conference. First, we review the rapidly evolving field of non-invasive hemodynamic monitoring and its potential to guide fluid removal by renal replacement therapy (RRT). We begin by summarizing the accumulating data associating fluid overload with harm in critical illness and the potential for harm from end-organ hypoperfusion caused by excessive fluid removal with RRT, underscoring the importance of accurate, dynamic assessment of volume status. We describe four applications of point-of-care ultrasound used to identify patients in need of urgent fluid removal or likely to tolerate fluid removal: lung ultrasound, inferior vena cava ultrasound, venous excess ultrasonography, and Doppler of the left ventricular outflow track to estimate stroke volume. We briefly introduce other minimally invasive hemodynamic monitoring technologies before concluding that additional prospective data are urgently needed to adapt these technologies to the specific task of fluid removal by RRT and to learn how best to integrate them into practical fluid-management strategies. Second, we focus on the growth of novel extracorporeal blood purification devices, starting with brief reviews of the inflammatory underpinnings of multiorgan dysfunction and the specific applications of pathogen, endotoxin, and/or cytokine removal and immunomodulation. Finally, we review a series of specific adsorptive technologies, several of which have seen substantial clinical use during the COVID-19 pandemic, describing their mechanisms of target removal, the limited existing data supporting their efficacy, ongoing and future studies, and the need for additional prospective trials.

Perioperative Point of Care Ultrasound for Hemodynamic Assessment: A Narrative Review

While transesophageal echocardiography (TEE) has traditionally been used in perioperative care, there is growing evidence supporting point of care ultrasound (POCUS) for the anesthesiologist in guiding patient care. It is a quick way to non-invasively evaluate hemodynamically unstable patients and ascertain their state of shock, determine volume status, and guide resuscitation in cardiac arrest. In addition, through use of POCUS, the anesthesiologist is able to identify signs of chronic heart disease to provide a more tailored and safer approach to perioperative care.

Subcostal versus right lateral ultrasound measurements of inferior vena cava: Measurements obtained from these two views are not equivalent in non-ICU patients

Objective

The objective of this study is to assess concordance between the subcostal and right lateral view for ultrasonographic inferior vena cava measurements including the end-inspiratory diameter, end-expiratory diameter and respiratory variation represented by the caval index in spontaneously breathing healthy adults.

Methods

We recruited a convenience sample of 33 healthy adults. A phased array ultrasound probe was used to obtain inferior vena cava measurements from a subcostal view in the sagittal plane and from a right lateral view in the coronal plane with B-mode ultrasound. End-inspiratory diameter, end-expiratory diameter and caval index were obtained for each view. A two-tailed t-test was performed to compare the caval indices obtained by the two views. Bland-Altman analysis was used to obtain the limits of agreement for the inferior vena cava diameter and caval index across the two views.

Results

Subcostal and right lateral caval indices across all participants were significantly different according to a paired t-test (p < 0.0001). The Bland-Altman analysis showed wide limits of agreement in end-inspiratory diameter (-0.97 and 0.50 cm) and in end-expiratory diameter (-0.94 and 0.90 cm). The right lateral view underestimated the inferior vena cava caval index relative to the subcostal view.

Conclusions

The subcostal and right lateral views are not equivalent in obtaining inferior vena cava measurements in spontaneously breathing healthy adults. Current cut-off values for measurement-based applications of inferior vena cava ultrasound, including fluid responsiveness using caval indices, may not be accurate when values are obtained from the right lateral view in the coronal plane of the inferior vena cava in patients.

Prevention of Intradialytic Hypotension in Hemodialysis Patients: Current Challenges and Future Prospects

Intradialytic hypotension, defined as rapid decrease in systolic blood pressure of greater than or equal to 20 mmHg or in mean arterial pressure of greater than or equal to 10 mmHg that results in end-organ ischemia and requires countermeasures such as ultrafiltration reduction or saline infusion to increase blood pressure to improve patient's symptoms, is a known complication of hemodialysis and is associated with several potential adverse outcomes. Its pathogenesis is complex and involves both patient-related factors such as age and comorbidities, as well as factors related to the dialysis prescription itself. Key factors include the need for volume removal during hemodialysis and a suboptimal vascular response which compromises the ability to compensate for acute intravascular volume loss. Inadequate vascular refill, incorrect assessment or unaccounted changes of target weight, acute illnesses and medication interference are further potential contributors. Intradialytic hypotension can lead to compromised tissue perfusion and end-organ damage, both acutely and over time, resulting in repetitive injuries. To address these problems, a careful assessment of subjective symptoms, minimizing interdialytic weight gains, individualizing dialysis prescription and adjusting the dialysis procedure based on patients' risk factors can mitigate negative outcomes.

Traumatic hemorrhage and chain of survival

Trauma is the number one cause of death among Americans between the ages of 1 and 46 years, costing more than $670 billion a year. Following death related to central nervous system injury, hemorrhage accounts for the majority of remaining traumatic fatalities. Among those with severe trauma that reach the hospital alive, many may survive if the hemorrhage and traumatic injuries are diagnosed and adequately treated in a timely fashion. This article aims to review the recent advances in pathophysiology management following a traumatic hemorrhage as well as the role of diagnostic imaging in identifying the source of hemorrhage. The principles of damage control resuscitation and damage control surgery are also discussed. The chain of survival for severe hemorrhage begins with primary prevention; however, once trauma has occurred, prehospital interventions and hospital care with early injury recognition, resuscitation, definitive hemostasis, and achieving endpoints of resuscitation become paramount. An algorithm is proposed for achieving these goals in a timely fashion as the median time from onset of hemorrhagic shock and death is 2 h.

Preanesthetic ultrasonography assessment of inferior vena cava diameter in the supine position, left lateral tilt position, and with the left uterine displacement maneuver in full-term pregnant women: A randomized cross-over design study

Preanesthetic ultrasonography assessment of inferior vena cava diameter (IVCD) in the supine position (SP), left lateral tilt position (LLT), and with the left uterine displacement maneuver (LUD) in full-term pregnant women: a randomized cross-over design study.

AIM

We pre-anesthetically measured IVCD using ultrasonography in the SP, LLT, and the LUD in full-term pregnant women, using a cross-over design, to evaluate the effectiveness of LLT and LUD on increasing IVCD, and the presence of inter-individual differences among patients in the effect of posture on IVCD.

METHODS

Twenty-two parturients scheduled for elective cesarean section under spinal anesthesia were recruited. All patients were sequentially placed in the SP, LLT, and with LUD before spinal anesthesia induction. Indices of IVCD, measured by subxiphoid ultrasonography, including maximum IVCD (IVCDmax), minimum IVCD (IVCDmin), and collapsibility index (CI) were recorded in each of the postures. Mean or median values of all measurements were compared among the postures.

RESULTS

The mean values of IVCDmax observed with both LLT and LUD were significantly larger than those in the SP, respectively (SP vs. LLT: p < 0.05, SP vs. LUD: p < 0.01), although there were no significant differences between IVCDmax with LLT and LUD. There were no significant differences in IVCDmin and CI between any of the postures. IVCDmax was highest with LUD in 11 patients (55%), in the LLT in seven patients (35%) and in the SP in two patients (10%).

CONCLUSIONS

LLT and LUD might be equally effective in enlarging the narrowed IVCD as compared to SP. However, both LLT and LUD might not necessarily be appropriate treatments to relieve IVC compression in some cases.

Lung Dysfunction and Chronic Kidney Disease: A Complex Network of Multiple Interactions

Chronic kidney disease (CKD) is a progressive disease that affects > 10% of the total population worldwide or >800 million people. CKD poses a particularly heavy burden in low- and middle-income countries, which are least able to cope with its consequences. It has become one of the leading causes of death worldwide and is one of the few non-communicable diseases where the number of related deaths has increased over the last two decades. The high number of people affected, and the significant negative impact of CKD should be a reason to increase efforts to improve prevention and treatment. The interaction of lung and kidney leads to highly complex and difficult clinical scenarios. CKD significantly affects the physiology of the lung by altering fluid homeostasis, acid-base balance and vascular tone. In the lung, haemodynamic disturbances lead to the development of alterations in ventilatory control, pulmonary congestion, capillary stress failure and pulmonary vascular disease. In the kidney, haemodynamic disturbances lead to sodium and water retention and the deterioration of renal function. In this article, we would like to draw attention to the importance of harmonising the definitions of clinical events in pneumology and renal medicine. We would also like to highlight the need for pulmonary function tests in routine clinical practise for the management of patients with CKD, in order to find new concepts for pathophysiological based disease-specific management strategies.

Point-of-care ultrasonography in nephrology comes of age

The physical exam is changing. Many have argued that the physical exam of the 21st century should include point-of-care ultrasound (POCUS). POCUS is being taught in medical schools and has been endorsed by the major professional societies of internal medicine. In this review we describe the trend toward using POCUS in medicine and describe where the practicing nephrologist fits in. We discuss what a nephrologist's POCUS exam should entail and we give special attention to what nephrologists can gain from learning POCUS. We suggest a 'nephro-centric' approach that includes not only ultrasound of the kidney and bladder, but of the heart, lungs and vascular access. We conclude by reviewing some of the sparse data available to guide training initiatives and give suggested next steps for advancing POCUS in nephrology.

How to Determine Fluid Management Goals during Continuous Kidney Replacement Therapy in Patients with AKI: Focus on POCUS

The utilization of kidney replacement therapies (KRT) for fluid management of patients who are critically ill has significantly increased over the last years. Clinical studies have suggested that both fluid accumulation and high fluid removal rates are associated with adverse outcomes in the critically ill population receiving KRT. Importantly, the ideal indications and/or fluid management strategies that could favorably affect these patients are unknown; however, differentiating clinical scenarios in which effective fluid removal may provide benefit to the patient by avoiding congestive organ injury, compared with other settings in which this intervention may result in harm, is direly needed in the critical care nephrology field. In this review, we describe observational data related to fluid management with KRT, and examine the role of point-of-care ultrasonography as a potential tool that could provide physiologic insights to better individualize decisions related to fluid management through KRT.

Evaluation of Intravascular Volume Using the Internal Jugular Vein Cardiac Collapse Index in the Emergency Department: A Preliminary Prospective Observational Study

A non-invasive method for assessment of intravascular volume for optimal fluid administration is needed. We here conducted a preliminary study to confirm whether cardiac variation in the internal jugular vein (IJV), evaluated by ultrasound, predicts fluid responsiveness in patients in the emergency department. Patients who presented to the emergency department between August 2019 and March 2020 and required infusions were enrolled. We recorded a short-axis video of the IJV, respiratory variability in the inferior vena cava and stroke volume variations using the ClearSight System (Edwards Lifesciences, Irvine, CA, USA) before infusion of 500 mL of crystalloid fluid. Cardiac variations in the cross-sectional area of the IJV were measured by speckle tracking. Among the 148 patients enrolled, 105 were included in the final analysis. Fluid responsiveness did not correlate with the cardiac collapse index (13.6% vs. 16.8%, p = 0.24), but correlated with stroke volume variations (12.5% vs. 15.6%, p = 0.026). Although it is a simple correction, the cardiac collapse index correlated with stroke volume corrected by age (r = 0.25, p = 0.01), body surface area (r = 0.33, p = 0.002) and both (r = 0.35, p = 0.001). Cardiac variations in the IJV did not predict fluid responsiveness in the emergency department, but may reflect stroke volume.

Reliability of Pre-Induction Inferior Vena Cava Assessment with Ultrasound for the Prediction of Post-Induction Hypotension in Neurosurgical Patients Undergoing Intracranial Surgery

Background

Hypotension is one of the most common complications following induction of general anesthesia. Preemptive diagnosis and correcting the hypovolemic status can reduce the incidence of post-induction hypotension. However, an association between preoperative volume status and severity of post-induction hypotension has not been established in neurosurgical patients. We hypothesized that preoperative ultrasonographic assessment of intravascular volume status can be used to predict post-induction hypotension in neurosurgical patients. Our study objective was to establish the relationship between pre-induction maximum inferior vena cava (IVC) diameter, collapsibility index (CI), and post-induction reduction in mean arterial blood pressure in neurosurgical patients.

Materials and Methods

A prospective observational study was conducted including 100 patients undergoing elective intracranial surgeries. IVC assessment was done before induction of general anesthesia. Receiver operating characteristic (ROC) curve analysis was used to determine the cutoff values of maximum and minimum IVC diameter (IVCD_max and IVCD_min, respectively) and CI for prediction of hypotension.

Results

Post-induction hypotension was observed in 41% patients. Patients with small IVCD_max and higher CI% developed hypotension. The areas under the ROC curve (AUCs) were 0.64 (0.53-0.75) for IVCD_max and 0.69 (0.59-0.80) for IVCD_min. The optimal cutoff values were1.38 cm for IVCD_max and 0.94 cm for IVCD_min. The AUC for CI was 0.65 (0.54-0.77) and the optimal cutoff value was 37.5%.

Conclusion

Pre-induction IVC assessment with ultrasound is a reliable method to predict post-induction hypotension resulting from hypovolemia in neurosurgical patients.

The Physical Examination to Assess for Anemia and Hypovolemia

Hypovolemia develops with the loss of extracellular fluid volume or blood. Rapidly identifying hypovolemia can be lifesaving. Indicators of hypovolemia on examination include supine or postural hypotension, increase in heart rate by 30 beats per minute or severe dizziness with standing, and a decrease in central venous pressure detected on visual inspection of the jugular venous pressure or ultrasound assessment of the inferior vena cava or internal jugular veins. Other findings with utility include a dry axilla and dry oral mucosa. With chronic anemia, hemodynamic changes detectable on examination may be minimal, as the body compensates by retaining extracellular volume.

Accurate Estimation of Right-Filling Pressure Using Handheld Ultrasound Score in Patients with Heart Failure

INTRODUCTION

This study aims to evaluate the accuracy of bedside assessment of inferior vena cava (IVC) and right internal jugular (RIJ) vein in predicting right atrial (RA) pressure in heart failure patients.

METHODS

We prospectively studied 124 heart failure patients who were referred to our catheterization laboratory for right heart catheterizations to assess hemodynamics and to guide heart failure management. Just prior to the procedure, a handheld ultrasound examination was performed in each patient. The volume status was assessed by estimating RA pressure using end-expiratory IVC dimension, IVC respiratory collapsibility, and RIJ respiratory collapsibility. Patients were divided into 2 groups based on invasive RA pressure value. Multiple logistic regression models were used to identify factors associated with RA ≥10 mm Hg; a 3-point simple score was then created. The performance of this score was assessed using the receiver operating characteristics curve.

RESULTS

In this study 124 heart failure patients were included; median age was 59 years (interquartile range 48-65), and 40% were female. RIJ respiratory collapsibility <50%, end-expiratory IVC dimension ≥21 mm, and respiratory collapsibility <50% were significantly associated with elevated RA pressure, and were used to build the score. The area under the receiver operating characteristics curve (AUC) for the 3-point score was 0.84 (0.77-0.92), and it performed better than 2-point score using IVC characteristics alone (AUC 0.84 [0.77-0.92] vs 0.75 [0.67-0.83]; P = .003). Of 124 patients, 90 patients (72.5%) had concordant RA pressure and pulmonary capillary wedge pressure.

CONCLUSION

Concomitant ultrasound assessment of RIJ and IVC correlated better with RA pressure than IVC alone. A simple 3-point score can provide a useful and easily accessible tool to estimate volume status, and further guide management of heart failure patients.

Inferior vena cava ultrasonography before general anesthesia cannot predict arterial hypotension in patients undergoing vascular surgery

INTRODUCTION

Intraoperative hypotension (IH) is an independent predictor of mortality. Some experts have suggested that ultrasound measurement of the inferior vena cava (IVC) in spontaneous ventilation can predict IH.

OBJECTIVE

To evaluate the capacity of ultrasound measures of IVC in spontaneous ventilation to predict episodes of IH after anaesthesia induction.

PATIENTS AND METHODS

We studied 55 high-risk cardiac patients undergoing vascular surgery. The maximum (dIVCmax) and minimum (dIVCmin) diameter of the IVC were measured and the collapsibility index CI = (dIVCmax-dIVCmin)/dIVCmax was calculated prior to anaesthesia induction. Three definitions of IH were used: systolic blood pressure (SBP) less than 100 mmHg, mean arterial pressure (MAP) less than 60 mmHg, and a decrease in MAP greater than or equal to 30% compared to baseline.

RESULTS

There were no significant differences in dIVCmax or in CI between patients presenting IH after anaesthesia induction and those who did not. ROC curves for dIVCmax showed an area under the curve of 0.55 (0.39-0.70), 0.69 (0.48-0.90), and 0.57 (0.42-0.73) and ROC curves for the CI were 0.62 (0.47-0.78), 0.60 (0.41-0.78) and 0.62 (0.47-0.78) for the 3 definitions of IH (<100 mmHg, MAP < 60 mmHg, and MAP ≥30% baseline), respectively.

CONCLUSIONS

Ultrasound measurements of IVC in spontaneous ventilation are not good predictors of IH after anaesthesia induction in these patients. The optimal cut-off points show low specificity and moderate sensitivity for predicting IH.

Inferior Vena Cava Collapsibility Index Can Predict Hypotension and Guide Fluid Management After Spinal Anesthesia

Purpose

We hypothesized that inferior vena cava collapsibility index (IVCCI)-guided fluid management would reduce the incidence of postspinal anesthesia hypotension in patients undergoing non-cardiovascular, non-obstetric surgery.

Methods

A receiver operating characteristic (ROC) curve was used to determine the diagnostic value of IVCCI for predicting hypotension after induction of spinal anesthesia and calculate the cut-off value. Based on the cut-off variation value, the following prospective randomized controlled trial aimed to compare the incidence of postspinal anesthesia hypotension between the IVCCI-guided fluid administration group and the standard fluid administration group. Secondary outcomes included the rate of vasoactive drug administration, the amount of fluid administered, and the incidence of nausea and vomiting.

Results

ROC curve analysis revealed that IVCCI had a sensitivity of 83.9%, a specificity of 76.3%, and a positive predictive value of 84% for predicting postspinal anesthesia hypotension at a cut-off point of >42%. The area under the curve (AUC) was 0.834 (95% confidence interval: 0.740–0.904). According to the cut-off variation value of 42%, the IVCCI-guided group exhibited a lower incidence of hypotension than the standard group [9 (15.3%) vs. 20 (31.7%), P = 0.032]. Total fluid administered was lower in the IVCCI-guided group than in the standard group [330 (0–560) mL vs. 345 (285–670) mL, P = 0.030].

Conclusions

Prespinal ultrasound scanning of the IVCCI provides a reliable predictor of hypotension following spinal anesthesia at a cut-off point of >42%. IVCCI-guided fluid management before spinal anesthesia can reduce the incidence of hypotension following spinal anesthesia.

Inferior Vena Cava Edge Tracking Echocardiography: A Promising Tool with Applications in Multiple Clinical Settings

Ultrasound (US)-based measurements of the inferior vena cava (IVC) diameter are widely used to estimate right atrial pressure (RAP) in a variety of clinical settings. However, the correlation with invasively measured RAP along with the reproducibility of US-based IVC measurements is modest at best. In the present manuscript, we discuss the limitations of the current technique to estimate RAP through IVC US assessment and present a new promising tool developed by our research group, the automated IVC edge-to-edge tracking system, which has the potential to improve RAP assessment by transforming the current categorical classification (low, normal, high RAP) in a continuous and precise RAP estimation technique. Finally, we critically evaluate all the clinical settings in which this new tool could improve current practice.

Management of hypertension and renin-angiotensin-aldosterone system blockade in adults with diabetic kidney disease: Association of British Clinical Diabetologists and the Renal Association UK guideline update 2021

People with type 1 and type 2 diabetes are at risk of developing progressive chronic kidney disease (CKD) and end-stage kidney failure. Hypertension is a major, reversible risk factor in people with diabetes for development of albuminuria, impaired kidney function, end-stage kidney disease and cardiovascular disease. Blood pressure control has been shown to be beneficial in people with diabetes in slowing progression of kidney disease and reducing cardiovascular events. However, randomised controlled trial evidence differs in type 1 and type 2 diabetes and different stages of CKD in terms of target blood pressure. Activation of the renin-angiotensin-aldosterone system (RAAS) is an important mechanism for the development and progression of CKD and cardiovascular disease. Randomised trials demonstrate that RAAS blockade is effective in preventing/ slowing progression of CKD and reducing cardiovascular events in people with type 1 and type 2 diabetes, albeit differently according to the stage of CKD. Emerging therapy with sodium glucose cotransporter-2 (SGLT-2) inhibitors, non-steroidal selective mineralocorticoid antagonists and endothelin-A receptor antagonists have been shown in randomised trials to lower blood pressure and further reduce the risk of progression of CKD and cardiovascular disease in people with type 2 diabetes. This guideline reviews the current evidence and makes recommendations about blood pressure control and the use of RAAS-blocking agents in different stages of CKD in people with both type 1 and type 2 diabetes.

Assessment of volemia status using ultrasound examination of the inferior vena cava and spectroscopic bioimpendance in hemodialysis patients

Background/Aim. Hypervolemia is an important risk factor for the development of cardiovascular morbidity and mortality in patients treated with regular hemodialysis. There is still no reliable method for assessing the status of volemia in these patients. The aim of the study was to assess the status of volemia in patients treated with regular hemodialysis by measuring the parameters of the inferior vena cava (IVC) and bioimpedance. Methods. The effect of hemodialysis treatment on ultrasound parameters of the IVC, as well as on the parameters measured by bioimpedance, was examined before and after hemodialysis. The values of the N-terminal prohormone of brain natriuretic peptide (NT-proBNP) were measured both before and after hemodialysis. Forty-five patients were involved in this non-interventional cross-section study, including the patients treated with standard bicarbonate dialysis. According to the interdialytic yield, the patients were divided into three groups: I (up to 2,000 mL), II (2,000?3,000 mL), and III (over 3,000 mL). Results. The values of the IVC parameters and the parameters measured with bioimpedance were significantly lower after treatment with hemodialysis (p < 0.005). The third group of patients had a significantly higher total fluid volume in the body com-pared to the group I, as well as a significantly greater volume of extracellular fluid (p < 0.005). The significantly lower values of NT-proBNP in all groups (p < 0.005) were detected after hemodialysis. After treatment with hemodialysis, a positive correlation was observed between the concentration of NT-proBNP in the serum and the extracellular/intracellular water ratio. However, the correlation between NT-proBNP concentration and total fluid measured by bioimpedance spectroscopy did not reach statistical significance. Conclusion. Measurement of the IVC ultrasound parameters and volemia parameters using bioimpedance significantly contributes to the assessment of the status of volemia. Nevertheless, it cannot be used as a separate parameter, only in combination with all other methods.

Goal-directed ultrasound protocol in patients with nontraumatic undifferentiated shock in the emergency department: prospective dual centre study

BACKGROUND AND IMPORTANCE

Early identification of the cause of shock is associated with better prognosis.

OBJECTIVE

The aim of this study was to explore the performances of an ultrasound protocol (echoSHOCK) to diagnose the cause of shock in the emergency department (ED).

DESIGN, SETTINGS AND PARTICIPANTS

This was a prospective study performed in two EDs. Included patients were older than 18 years admitted with shock. After routine workup strategy, the suspected cause of shock and the planned treatment were reported. The echoSHOCK protocol, using only B mode, was then performed. After performing echoSHOCK, the investigator reported the same two items.

INTERVENTION

echoSHOCK protocol that assessed: compressive pericardial effusion (tamponade), right ventricle dilatation and flattening of the septum, left ventricle dimension and systolic function, indices of hypovolemia.

OUTCOMES MEASURE AND ANALYSIS

We defined four different causes for shock (tamponade, acute cor pulmonale, cardiogenic and hypovolemia). The primary endpoint was the degree of agreement of the routine workup and echoSHOCK with an expert panel.

MAIN RESULTS

85 patients [mean age of 73 (14) years] were included. Kappa coefficients between routine strategy and echoSHOCK for the cause of shock, with the expert panel were 0.33 (95% CI, 0.26-0.4) and 0.88 (95% CI, 0.83-0.93), respectively. Likewise, for the planned treatment, kappa were 0.21 (95% CI, 0.14-0.28) and 0.9 (95% CI, 0.85-0.94), respectively. The physician's confidence increased from 3.9 (2.1) before echoSHOCK to 9.3 (1.1) after, (P < 0.001).

CONCLUSION

This study suggested that echoSHOCK significantly increased the ability to determine the cause of undifferentiated shock in the ED.

Ultrasonographic Assessment of Extravascular Lung Water in Hospitalized Patients Requiring Hemodialysis: A Prospective Observational Study

INTRODUCTION

Sonographic technologies can estimate extravascular lung water (EVLW) in hemodialysis (HD) patients. This study investigated the suitability of a handheld scanner in contrast to a portable scanner for quantifying EVLW in hospitalized patients requiring HD.

METHODS

In this prospective study, 54 hospitalized HD patients were enrolled. Bedside lung ultrasound was performed within 30 min before and after dialysis using handheld (phased array transducer, 1.7-3.8 MHz) and portable (curved probe, 5-2 MHz) ultrasound devices. Eight lung zones were scanned for total B-lines number (TBLN). The maximum diameter of inferior vena cava (IVC) was measured. We performed Passing-Bablok regression, Deming regression, Bland-Altman, and logistic regression analysis.

RESULTS

The 2 devices did not differ in measuring TBLN and IVC (p > 0.05), showing a high correlation (r = 0.92 and r = 0.51, respectively). Passing-Bablok regression had a slope of 1.11 and an intercept of 0 for TBLN, and the slope of Deming regression was 1.02 within the CI bands of 0.94 and 1.11 in the full cohort. TBLN was logarithmically transformed for Bland-Altman analysis, showing a bias of 0.06 (TBLN = 1.2) between devices. The slope and intercept of the Deming regression in IVC measurements were 0.77 and 0.46, respectively; Bland-Altman plot showed a bias of -0.07. Compared with predialysis, TBLN significantly (p < 0.001) decreased after dialysis, while IVC was unchanged (p = 0.16). Univariate analysis showed that cardiovascular disease (odds ratio [OR] 8.94 [2.13-61.96], p = 0.002), smoking history (OR 5.75 [1.8-20.46], p = 0.003), and right pleural effusion (OR 5.0 [1.2-25.99], p = 0.03) were strong predictors of EVLW indicated by TBLN ≥ 4.

CONCLUSION

The lung and IVC findings obtained from handheld and portable ultrasound scanners are comparable and concordant. Cardiovascular disease and smoking history were strong predictors of EVLW. The use of TBLN to assess EVLW in hospitalized HD patients is feasible. Further studies are needed to determine if TBLN can help guide volume removal in HD patients.

A Novel Non-Invasive Device for the Assessment of Central Venous Pressure in Hospital, Office and Home

Background

Venous congestion can be quantified by central venous pressure (CVP) and its monitoring is crucial to understand and follow the hemodynamic status of patients with cardio-respiratory diseases. The standard technique for CVP measurement is invasive, requiring the insertion of a catheter into a jugular vein, with potential complications. On the other hand, the current non-invasive methods, mainly based on ultrasounds, remain operator-dependent and are unsuitable for use in the home environment. In this paper, we will introduce a novel, non-invasive device for the hospital, office and home assessment of CVP.

Methods

After describing the measurement concept, we will report a preliminary experimental study enrolling 5 voluntary healthy subjects to evaluate the VenCoM measurements’ repeatability, and the system’s capability in measuring small elicited venous pressure variations (2 mmHg), as well as an induced venous hypertension within a pathological range (12÷20 mmHg).

Results

The experimental measurements showed a repeatability of ±1mmHg. The VenCoM device was able to reliably detect the elicited venous pressure variations and the simulated congestive status.

Discussion and Conclusion

The proposed non-invasive VenCoM device is able to provide a fast and repeatable CVP estimate, having a wide spectrum of potential clinical applications, including the monitoring of venous congestion in heart failure patients and in subjects with renal and hepatic dysfunction, as well as pulmonary hypertension (PH) that can be extended to pneumonia COVID-19 patients even after recovery. The device needs to be tested further on a large sample size of both healthy and pathological subjects, to systematically validate its reliability and impact in clinical setting.

[Evaluation of the fluid balance in geriatric patients-What contribution can abdominal ultrasound make?]

The assessment of the fluid balance as well as the identification of hyperhydration and dehydration often represent a diagnostic challenge, especially in older patients. In principle, various diagnostic procedures and approaches are suitable for assessment of the various facets, by which such a disorder can be recognized. The contribution of abdominal ultrasound is described and evaluated in the context of the different diagnostic procedures. An overview of the current situation with respect to assessment of the vena cava is provided. In many respects there is no strict consensus concerning the thresholds of the individual measurements and the value of the different measurements. Currently, an orthograde diameter of the inferior vena cava > 2 cm is accepted as being a good indicator for hyperhydration. Less certain are analogously derived thresholds as indicators for dehydration.

Multi-Method Complex Approach for Hydration Assessment Does Not Detect a Hydration Difference in Hemodialysis versus Peritoneal Dialysis Patient

Assessment of hydration status is essential in monitoring the effectiveness of renal replacement therapy and is usually based on physical examination. However, comparisons of hydration status achieved with different dialysis methods are not conclusive. We compared the hydration status of patients on chronic hemodialysis (HD, n = 60) and peritoneal dialysis (PD, n = 20) in a comprehensive assessment including physical examination and additional methods. The mean age of the 80 chronically dialyzed patients (53 males, 27 females) was 58.1 ± 13.9 years. The clinical evaluation took into account the presence of peripheral edema, dyspnea, and crackling over the lung fields. Additional tests included lung ultrasound, electrical bioimpedance (performed in 79 patients), impedance cardiography, ultrasound assessment of large abdominal vessels (performed in 79 patients), select echocardiographic parameters (obtained in 78 patients), and serum NT-proBNP concentration. Residual diuresis volume was significantly higher in the PD group. We found no significant differences between the two groups in any other baseline characteristics or in the results of the clinical examination or additional tests. The use of different methods for assessing hydration does not allow differentiation of patients treated with dialysis in terms of the dialysis technique used. Therefore, it seems reasonable to use common algorithms to objectify the hydration status of these patients.

Comparison between lung ultrasonography and current methods for volume assessment in Asian chronic hemodialysis patients

INTRODUCTION

Volume assessment in end-stage kidney disease patients on hemodialysis (HD) remains inadequate by existing methods: clinical examination, bioimpedance spectroscopy, measurement of inferior vena cava diameter by ultrasound (IVCD), and plasma B-type natriuretic peptide (NT-pro BNP). This study aims to compare the performance of lung ultrasound against existing methods for volume assessment in a HD cohort.

METHODS

Two nephrologists independently performed 28-point lung ultrasound immediately before and after midweek HD in 50 patients. Lung congestion was classified into mild, moderate, and severe categories based on lung ultrasound findings. Clinical examination for crepitations and oedema, change in hydration status (∆HS) measured by bioimpedance spectroscopy, NT-pro BNP, IVCD during inspiration (IVCDimin), expiration (IVCDimax), and inferior vena cava collapsibility index were also assessed before and after midweek HD.

FINDINGS

In all, 61% of patients with normohydration status by bioimpedance spectroscopy had moderate or severe lung congestion on lung ultrasound. There were significant correlations between predialysis lung ultrasound, and NT-pro BNP (r = 0.432, P = 0.004), ∆HS (r = 0.447, P < 0.001), and IVCD parameters (P < 0.05). Some correlations weakened postdialysis (∆HS [r = 0.322, P = 0.01] and IVCDimax [r = 0.307, P = 0.03]), whereas NT-pro BNP and ∆HS paradoxically increased in 28% and 30% of the cohort, respectively. On receiver operator curve analysis, most methods of volume assessment had limited discriminatory power to detect mild lung congestion.

DISCUSSION

Lung ultrasound demonstrates some comparability with existing volume assessment methods in Asian dialysis patients. However, it appears more effective at detecting subclinical pulmonary congestion, and tracking fluid changes real-time compared to bioimpedance spectroscopy and NT-pro BNP.

Ultrasound Measurement of Inferior Vena Cava Collapsibility as a Tool to Predict Propofol-Induced Hypotension

Background:

Hypotension is common under anesthesia and can cause organ underperfusion and ischemia, especially during induction. This could be because of the cardiovascular depressant and vasodilatory effects of anesthetic agents, as well as lack of surgical stimulation.

Aim of Study:

The aim was to evaluate the utility of preinduction inferior vena cava (IVC) measurement to predict significant hypotension after induction of anesthesia with propofol.

Settings and Design:

This was a prospective, open-label study conducted in a tertiary care institute.

Subjects and Methods:

This study was conducted on 50 patients undergoing general anesthesia. Ultrasound machine (Mindray® M7) was used to visualize IVC. The measurements taken were maximum diameter of IVC (IVC_max) and minimum diameter of IVC (IVC_min). IVC collapsibility index (IVC-CI) was calculated as (IVC_max − IVC_min)/IVC_max and was expressed as a ratio.

Statistical Tests Used:

Receiver operating characteristic (ROC) curve analysis and Chi-square test were used for statistical tests.

Results:

The relation between significant hypotension and IVC-CI was evaluated using ROC curve analysis. We found the area under curve to be 0.959 and a cutoff of 0.43 (43% collapsibility). The association of significant hypotension with IVC-CI of >43% was calculated and found to be statistically significant (P < 0.001). The sensitivity of IVC CI of >43% in predicting development of significant hypotension was 86.67% and the specificity was 94.29%. It had very high negative and positive predictive values (94.29% and 86.67%, respectively) with an accuracy of 92%.

Conclusion:

Patients with an IVC collapsibility of more than 43%, as assessed by ultrasonography, are more likely to develop significant hypotension after induction with propofol.

Caval Aortic Index: A Novel Tool for Fluid Assessment in Obstetric Emergencies

Background:

Uncorrected maternal hypotension occurring during obstetric emergencies may result in maternal and fetal morbidity. Fluid status of the pregnant mother is a major variable which affects the maternal hemodynamics during patient management, and there is no objective assessment tool for the same. A relatively new sonographic parameter, the inferior vena cava aorta (IVC/Ao) diameter index or caval aortic index, showed promise in this regard, and its application was studied in obstetric patients.

Methodology:

A prospective analytical study was conducted involving 50 pregnant and 50 nonpregnant women of reproductive age group. Using both subxiphoid and transhepatic views, their normal fasting caval aortic indices were determined from the ratio of mean IVC diameter to the mean aortic diameter. Descriptive and inferential statistical analyses were carried out accordingly.

Results:

Normal IVC/Ao diameter index for nonpregnant healthy women of reproductive age was 1.11 ± 0.29 in the subxiphoid view and 1.21 ± 0.33 in the transhepatic view. The difference between the two views was not statistically significant. IVC/Ao diameter index for a normal term pregnant woman was 1.03 ± 0.26, and term pregnancy does not significantly cause variation in the index.

Conclusions:

Caval aortic index is a useful noninvasive tool to assess volume status and guide fluid management in pregnant women presenting to the emergency department, and the transhepatic view is comparable to the traditional subxiphoid view for the measurement of the same.

Diagnostic efficacy of bedside ultrasound to detect dehydration in older patients attending an emergency care unit

BACKGROUND

The diagnosis of dehydration in older patients remains a challenge because clinical and laboratory signs are unspecific. The use of B‑Mode ultrasound of the inferior vena cava is proposed to aid in the diagnosis but data concerning diagnostic efficacy of bedside ultrasound are lacking.

METHODS

In this study 78 patients ≥65 years old referred to the emergency unit of a university hospital and identified as being dehydrated by applying clinical signs were compared with a reference of 121 patients. The diameter of the inferior vena cava (IVC) was assessed by ultrasound while compressing the IVC during an inspiratory maneuver and the minimum and maximum diameter in M‑Mode.

RESULTS

Significant differences were found concerning compressibility, variability of the diameter assessed by M‑Mode and the diameter during an inspiratory maneuver of the IVC (<0.001); however, a receiver operator characteristics (ROC) showed only moderate values for diagnostic efficacy for all these parameters where the best result was found for the inspiratory maneuver (Area under the curve [AUC] = 0.73). To reach a specificity of 0.8 to diagnose dehydration, a cut-off value of ≤0.4 cm for IVC diameter was suitable.

CONCLUSION

Ultrasound of the IVC can easily be applied in a bedside setting and may be helpful in identifying dehydration in older patients; however, this remains challenging and a synopsis covering clinical and technical data is indispensable.

Endothelin-1/Nitric Oxide Ratio as a Predictive Factor of Response to Therapy With Terlipressin and Albumin in Patients With Type-1 Hepatorenal Syndrome

Background and Purpose

Predictors of response to type-1 hepatorenal syndrome (HRS) therapy are urgently needed. This study's purpose is to evaluate the proposed predictors in these patients.

Methods

Forty-two type-1 HRS patients with cirrhosis were treated with albumin and terlipressin. Clinical, biochemical, and demographic parameters taken at the onset of therapy and changes in endothelin-1/nitric oxide (ET-1/NO) ratio during therapy were analyzed to check their predictive value.

Results

Response to treatment (serum creatinine level <1.5 mg/dL at the end of therapy) was shown in 20 patients (48%). Independent predictive variables of response to therapy were early reduction of ET-1/NO ratio ≥0.15 at day 3 of therapy and serum bilirubin baseline <8 mg/dL (area under the receiver operating characteristic curve, 0.751; P < 0.001; specificity, 55%; sensitivity, 85%). Response rates in patients with serum bilirubin level <8 and ≥8 mg/dL were 63% and 20%, respectively (P = 0.008). The corresponding values in patients with an early reduction of ET-1/NO ratio ≥0.15 and <0.15 on day 3 were 85% and 13.6%, respectively (P < 0.001).

Conclusions

Early reduction of ET-1/NO ratio and lower serum bilirubin baseline can predict response to type-1 HRS therapy with albumin and terlipressin. Alternative therapy should be investigated for nonresponder type-1 HRS patients.

The utility and limitation of inferior vena cava diameter as a dry weight marker

BACKGROUND

IVC diameter on expiration (IVCdexp) is measured by echocardiography routinely. It is used to estimate volume status and designated as a definitive marker for determining dry weight (DW) in patients undergoing hemodialysis (HD).

METHODS

A cross-sectional study. Outpatients (n = 107), and inpatients (n = 35) undergoing HD were enrolled. IVCdexp was measured on non-dialysis days in outpatients and dialysis days before and after the dialysis session in inpatients. In outpatients, the relationship of IVCdexp with echocardiography findings and clinical characteristics was analyzed. IVCdexp was compared with the other DW markers as a predictive factor for intradialytic hypotension. In inpatients, IVCdexp was analyzed by dividing inpatients with or without fluid in extravascular space.

RESULTS

IVCdexp ranged from 5.4 to 16.9 mm in outpatients who had optimal DW. IVCdexp could reflect on volume status, but not predictive for intradialytic hypotension and not suggestive of fluid in extravascular space.

CONCLUSIONS

IVCdexp was a rough marker to estimate volume status and only useful in suggesting apparent hypervolemia or hypovolemia. We should know that the IVCdexp value is affected by a lotof factors and not a definitive marker for estimating practical DW. J. Med. Invest. 66 : 172-177, February, 2019.

The role of right ventricular volumes and inferior vena cava diameters in the evaluation of volume status before colonoscopy

Background/aim

Ultrasonographic measurements of inferior vena cava (IVC) diameters and right ventricle (RV) volumes are important tools for the evaluation of intravascular volume. The current study investigates the association of IVC diameters and RV volumes before colonoscopy in prediction of postanesthesia hypotension.

Materials and methods

Seventy patients scheduled for colonoscopy were included in the study. Preoperatively, expirium (dIVC max) and inspirium (dIVC min) IVC diameters were measured using M-mode ultrasonography and the collapsibility index (IVC-CI) was calculated. Ventricular volumes and areas were also measured using transthoracic echocardiography. Postanesthesia hypotension was defined as mean arterial blood pressure of <60 mmHg or a decrease of >30% in the mean arterial pressure after sedation.

Results

Minimum and maximum IVC diameters were significantly lower (P = 0.005 and P < 0.001, respectively) and IVC-CI was significantly higher (P < 0.001) in patients who developed hypotension. Similarly, right ventricular end-diastolic area (RV-EDA), right ventricular end-systolic area (RV-ESA), right ventricular end-diastolic volume (RV-EDV), right ventricular end-systolic volume (RVESV), and left ventricular end-systolic volume (LV-ESV) values were significantly lower in patients with hypotension (P < 0.05). Logistic regression analysis showed that dIVC min and RV-ESA were independent predictors of hypotension.

Conclusion

IVC diameters and RV-ESA, RV-EDA, RV-ESV, and RV-EDV are good indicators of preoperative volume status and can be used to predict the patients at risk of developing hypotension.

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.

Ultrasound-based clinical profiles for predicting the risk of intradialytic hypotension in critically ill patients on intermittent dialysis: a prospective observational study

BACKGROUND

Intradialytic hypotension, a complication of intermittent hemodialysis, decreases the efficacy of dialysis and increases long-term mortality. This study was aimed to determine whether different predialysis ultrasound cardiopulmonary profiles could predict intradialytic hypotension.

METHODS

This prospective observational single-center study was performed in 248 critically ill patients with acute kidney injury undergoing intermittent hemodialysis. Immediately before hemodialysis, vena cava collapsibility was measured by vena cava ultrasound and pulmonary congestion by lung ultrasound. Factors predicting intradialytic hypotension were identified by multiple logistic regression analysis.

RESULTS

Intradialytic hypotension was observed in 31.9% (n = 79) of the patients, interruption of dialysis because of intradialytic hypotension occurred in 6.8% (n = 31) of the sessions, and overall 28-day mortality was 20.1% (n = 50). Patients were classified in four ultrasound profiles: (A) 108 with B lines > 14 and vena cava collapsibility > 11.5 mm m^-2, (B) 38 with B lines < 14 and vena cava collapsibility ≤ 11.5 mm m^-2, (C) 36 with B lines > 14 and vena cava collapsibility Di ≤ 11.5 mm m^-2, and (D) 66 with B lines < 14 and vena cava collapsibility > 11.5 mm m^-2. There was an increased risk of intradialytic hypotension in patients receiving norepinephrine (odds ratios = 15, p = 0.001) and with profiles B (odds ratios = 12, p = 0.001) and C (odds ratios = 17, p = 0.001).

CONCLUSION

In critically ill patients on intermittent hemodialysis, the absence of hypervolemia as assessed by lung and vena cava ultrasound predisposes to intradialytic hypotension and suggests alternative techniques of hemodialysis to provide better hemodynamic stability.

Improved Repeatability of the Estimation of Pulsatility of Inferior Vena Cava

The inferior vena cava (IVC) shows variations of cross section over time (pulsatility) induced by different stimulations (e.g., breathing and heartbeats). Pulsatility is affected by patients' volume status and can be investigated by ultrasound (US) measurements. An index of IVC pulsatility based on US visualization and called caval index (CI) was proposed as a non-invasive indirect measurement of the volume status. However, its estimation is not standardized, operator dependent and affected by movements of the vein and non-uniform pulsatility. We introduced a software that processes B-mode US video clips to track IVC movements and estimate CI on an entire portion of the vein. This method is here compared to the standard approach in terms of repeatability of the estimated CI, reporting on the variability over different respiratory cycles, longitudinal IVC sections and intra-/inter-observers. Our method allows to reduce the variability of CI assessment, making a step toward its standardization.

Internal medicine residents' point-of-care ultrasound skills and need assessment and the role of medical school training

Introduction: Point-of-care-ultrasound (POCUS) as a useful bedside tool is growing. Few studies have examined residents' attitude towards POCUS or compared POCUS image interpretation skills between residents with and without POCUS training in medical school. Material and Methods: We distributed an anonymous survey and image interpretation test to assess residents' attitude towards POCUS, confidence, and skills in interpreting POCUS images and videos. Using independent samples t-tests, we compared mean confidence levels and test scores between residents with and without prior POCUS training. Results: Fifty-two residents responded to survey (response rate 68%) and 59 took the image interpretation test (77%). Most residents (90%) reported being interested in POCUS. Residents with prior POCUS training (n=13) were either PGY-1 (9) or PGY-2 (4). No PGY-3 resident had prior training. Most residents (83%) thought POCUS could be extremely useful in the inpatient setting compared to 29% for outpatient setting. PGY-1 residents with prior training had a higher mean confidence level than PGY-1 residents without prior training, but the difference was not statistically significant (3.26 vs 2.64; p=0.08). PGY-1 with prior training had a mean confidence level that was close to that of PGY-3 residents. PGY-1 residents with prior training scored significantly higher than PGY-1 residents without prior training in image interpretation test (10.25 vs 7; p=0.01). Residents felt most confident in interpreting inferior vena cava images (mean 3.7; max. 5), which also had the highest score in image interpretation test (correct response rate of 88%). Conclusion: Our residents seem very interested in POCUS. PGY-1 residents with prior POCUS training in medical school seem to have higher confidence in their POCUS skills than PGY-1 residents without prior training and outperformed them in image interpretation test. The study is very instructive in building our future POCUS curriculum for residents.

Diagnostic accuracy of inferior vena caval respiratory variation in detecting fluid unresponsiveness: A systematic review and meta-analysis

BACKGROUND

The accuracy of respiratory variation of the inferior vena cava (rvIVC) in predicting fluid responsiveness, particularly in spontaneously breathing patients is unclear.

OBJECTIVES

To consider the evidence to support the accuracy of rvIVC in identifying patients who are unlikely to benefit from fluid administration.

DESIGN

Systematic review and meta-analysis.

DATA SOURCE

We searched MEDLINE, EMBASE, Cochrane Library, KoreaMed, LILCAS and WHO Clinical Trial Registry from inception to June 2017.

ELIGIBILITY CRITERIA

Case-control or cohort studies that evaluated the accuracy of rvIVC in living adult humans were included. A study was included in the meta-analysis if data enabling construction of 2 × 2 tables were reported, calculated or could be obtained from authors and met the above cited criteria.

RESULT

A total of 23 studies including 1574 patients were included in qualitative analysis. The meta-analysis involved 20 studies and 761 patients. Pooled sensitivity and specificity of rvIVC in 330 spontaneously breathing patients were 0.80 [95% confidence interval (CI) 0.68 to 0.89] and 0.79 (95% CI 0.60 to 0.90). Pooled sensitivity and specificity of rvIVC in 431 mechanically ventilated patients were 0.79 (95% CI 0.67 to 0.86) and 0.70 (95% CI 0.63 to 0.76).

CONCLUSION

Decreased inferior vena caval respiratory variation is moderately accurate in predicting fluid unresponsiveness both in spontaneous and mechanically ventilated patients. The findings of this review should be used in the appropriate clinical context and in conjunction with other clinical assessments of fluid status.

IDENTIFIER

CRD 42017068028.