Secondary Logo

Share this article on:

Point-of-care ultrasound in end-stage kidney disease

beyond lung ultrasound

Beaubien-Souligny, Williama,b; Bouchard, Joséec; Denault, Andréb,d

Current Opinion in Nephrology and Hypertension: November 2018 - Volume 27 - Issue 6 - p 487–496
doi: 10.1097/MNH.0000000000000453
DIALYSIS AND TRANSPLANTATION: Edited by J. Kevin Tucker and Anil Chandraker

Purpose of review Following the miniaturization of ultrasound devices, point-of-care ultrasound (POCUS) has been proposed as a tool to enhance the value of physical examination in various clinical settings. The objective of this review is to describe the potential applications of POCUS in end-stage renal disease patients (ESRD).

Recent findings With basic training, the clinician can perform pulmonary, vascular, cardiac, and abdominal POCUS at the bedside of ESRD patients. Pulmonary ultrasound can be used to quantify pulmonary congestion and for the differential diagnosis of dyspnea. Ultrasound of the inferior vena cava combined with simple cardiac ultrasound can be used to promptly investigate the mechanism of hemodynamic instability. Vascular ultrasound can be used for troubleshooting of arteriovenous fistula problems and for catheter installation. Multiple potential applications of POCUS in the ESRD population are reviewed, including areas of future research.

Summary Acquiring basic skills in POCUS may improve patient care through the rapid identification of threats, improved diagnostic abilities for common symptoms, and safer procedures. The adoption of POCUS in undergraduate, internal medicine and nephrology training curriculums will likely lead to a gradual introduction of this technology in the care of ESRD patients.

aDivision of Nephrology, Centre Hospitalier de l’Université de Montréal

bDepartment of Anesthesiology and Intensive Care, Montreal Heart Institute

cDivision of Nephrology, Hôpital Sacré-Coeur de Montreal,

dDivision of Intensive Care, Centre Hospitalier de l’Université de Montréal, Montréal, Québec, Canada

Correspondence to André Denault, MD, PhD, Montreal Heart Institute, 5000 Belanger St., Montreal, Quebec H1T 1C8, Canada. Tel: +1 514 376 3330; fax: +1 514 376 1355; e-mail: andre.denault@umontreal.ca

Back to Top | Article Outline

INTRODUCTION

An integral part of the care of end-stage renal disease (ESRD) patients is the time during which an attending nephrologist is at the bedside. During these time periods, an attentive clinician can solve acute and long-term problems by careful history taking and physical examination. The physical examination usually includes inspection, palpation, percussion, and auscultation. However, the traditional physical examination is known to be of limited value to detect common clinical problems such as fluid overload [1–3]. To identify immediate and long-term threats, the right tool in the right hands might be a decisive factor. Following the miniaturization of ultrasound devices, insonation has been proposed as the fifth pillar of physical examination [4▪▪]. Point-of-care ultrasound (POCUS) is now commonly used in emergency medicine, anesthesiology, and critical care medicine. The guiding principle is that a focused evaluation at the bedside performed by a trained clinician can help answer a clinical question. The goal of this approach is not to replace traditional diagnostic ultrasound performed by specialists, but to enable clinicians to take informed decisions based on objective findings in a timely manner. An ultrasound assessment can also be repeated to monitor the response following an intervention. This rationale has recently gained acceptance in fields which traditionally favored detailed diagnostic ultrasound such as cardiology [4▪▪]. Nevertheless, at the present time, more than 80% of American nephrology fellows do not receive POCUS training [5]. The objective of this short review is to describe the applications of POCUS in ESRD patients. We will briefly review the recent developments concerning the use of lung ultrasound in dialysis patients. Additionally, we will explore the role of cardiac, abdominal, and vascular access ultrasound by giving clinical examples on how POCUS could contribute to facilitate the diagnosis or management of problems in ESRD patients.

Box 1

Box 1

Back to Top | Article Outline

LUNG ULTRASOUND IN END-STAGE RENAL DISEASE PATIENTS

Air represents a barrier to ultrasounds compared to solid tissues or liquids. Consequently, the normal aerated lung parenchyma is not seen when performing ultrasound. However, pathological processes can be diagnosed using ultrasound by detecting abnormal images or artifacts. Pulmonary congestion, represented by extra-vascular lung water (EVLW), can be measured semi-quantitatively by detecting an artifact named B-line or comet-tail. This artifact is caused by the reverberations of sound between aerated and fluid-filled lung parenchyma adjacent to the visceral pleura [6]. An example is shown in Fig. 1. This “artifact" marker can be seen in patients with cardiogenic lung edema, acute respiratory distress syndrome (ARDS), or other interstitial lung disease such as pulmonary fibrosis [7]. However, this artifact will be absent in other causes of dyspnea such as chronic obstructive pulmonary disorder (COPD) or asthma. As such, it has been successfully used in the emergency department to differentiate between acute COPD exacerbation and lung edema in the acutely dyspneic patient [8]. In critically ill patients, the quantification of B-lines was demonstrated to be accurate for EVLW compared with wedge pressure, chest radiography or quantified using the indicator dilution method [9].

FIGURE 1

FIGURE 1

Observational studies have demonstrated that pulmonary B-lines are detected in ESRD patients even in the absence of overt symptoms such as dyspnea or peripheral edema [10,11]. Moreover, B-line count decreases during hemodialysis proportionally to fluid removal [12,13▪]. The adverse effects of chronic pulmonary congestion measured by B-line assessment have been investigated in ESRD patients. In one study, the amount of detected B-lines was associated with impairment in physical functioning [14] and moderate (>15 B-lines) to severe (>60 B-lines) pulmonary congestion was associated with an increased mortality risk in two large prospective cohorts of patients [15,16]. However, in a subsequent study, adding this measurement to other commonly used prognostic factors and left ventricular mass index measured by echocardiography did not improve the prediction of mortality [17].

Lung ultrasound may help clinicians in a variety of clinical contexts. In a dyspneic hemodialysis patient arriving for his treatment, assessing pulmonary B-lines may help to differentiate pulmonary edema from an exacerbation of COPD, leading to a correct diagnosis and appropriate intervention in a timely manner [18]. Identifying patients with a high bilateral B-line burden may also prevent short-term hospitalizations for pulmonary edema. In a recent observational study by our group, patients with B-lines present in more than 20% of lung regions after hemodialysis had a 50% risk of hospitalization for pulmonary edema in the following year [13▪]. An asymmetric pattern of B-lines suggests the presence of a lung consolidation adjacent to the visceral pleura which can sometimes be seen when the parenchyma is completely filled with fluid (as shown in Fig. 1d). Pneumonia can be challenging to diagnose in dialysis patients and lung ultrasound is a useful adjunct for the clinician [19]. Additionally, the examination may reveal pleural effusion which are due to overhydration in more than 60% of cases but may also be the hallmark of uremic pleuritis [20]. An example of a large pleural effusion is presented in Fig. 1e. Finally, in the patient with dyspnea after dialysis catheter installation, the absence of pleural motion or lung sliding is a rapid and reliable method to detect a pneumothorax [21]. This might be relevant to diagnose in dyspneic patients following insertion of a dialysis catheter in the jugular or subclavian area.

Whether the reduction of pulmonary B-lines should be considered a treatment target to improve the prognosis of hemodialysis patients is currently under investigation. A multicenter randomized controlled trial (LUST study) is underway, aiming to reduce the total number of B-lines to less than 15 by progressively increasing fluid removal in patients at high risk for cardiovascular events. In a related open-label randomized controlled trial in which low-risk patients of two hemodialysis centers were included, this intervention did not result in a reduction in cardiovascular events or mortality over a 2-year period (22.8% in the intervention group vs. 20.5% in the control group, P = 0.75) [22▪▪]. Of note, this study was underpowered for the primary endpoint (death or first cardiovascular event). However, the nonsignificant increase in events in the intervention group suggests that targeting a B-line score of less than 15 by reducing target weight may not be valid strategy to improve outcomes in low-risk hemodialysis patients. Pending the results of the LUST trial, clinicians should be aware that the use of pulmonary ultrasound to guide precise target weight prescription in the long term has not been demonstrated to improve outcomes, as for other technologies such as bioimpedance or blood volume monitoring [23▪,24].

Back to Top | Article Outline

INFERIOR VENA CAVA ULTRASOUND IN END-STAGE RENAL DISEASE PATIENTS PATIENTS

Imaging of the inferior vena cava (IVC) using POCUS can be performed reliably with basic training and equipment [25]. This assessment has been studied to estimate central venous pressure (CVP) and to predict fluid responsiveness in critically ill patients. Although IVC diameter measurements are not able to precisely estimate CVP values, they can discriminate between normal/low CVP and high CVP values [26,27]. As shown in Fig. 2a and b, an IVC diameter of >21 mm with a variation of <50% with sudden inspiration [26] or <20% during normal breathing [28] reflects a high CVP (10–20 mmHg). In opposition, an IVC diameter of ≤21 mm and respiratory variations >20% are associated with a normal CVP (0–5 mmHg) (Fig. 2c and d) [28]. Additionally, as the CVP increases, the IVC changes from an oval form to a spherical form. A ratio >0.69 between the anteroposterior and the lateral diameter is associated with a high CVP (≥10 mmHg) [29▪].

FIGURE 2

FIGURE 2

In ESRD patients, measurements of the IVC diameter and collapsibility have been studied as a tool to help target weight prescription in observational studies. In a sub-study of the Dry-weight Reduction in hypertensive hemodialysis Patients (DRIP) trial [30], IVC ultrasound was performed 30 to 60 min after dialysis [31]. In this study, IVC diameter decreased in the intervention group subjected to incremental reduction in target weight. However, no relationship was found between IVC and blood pressure measurements during the intervention. In a recent study, IVC and bioimpedance measurements were performed before dialysis in 16 pediatric patients. IVC measurements did not correlate with extracellular fluid volume [32]. Only one study reported IVC ultrasound in peritoneal dialysis patients. In this population, a correlation was found between IVC measurements and plasma atrial natriuretic peptide [33]. In summary, the role of IVC ultrasound in target weight prescription in ESRD patients remains unclear.

In specific situations, IVC ultrasound may be useful to the attending physician. In patients with significant diuresis, an IVC value suggestive of a normal CVP in conjunction with the absence of pulmonary B-lines before dialysis may identify patients for whom fluid removal is unnecessary and might lead to repeated hypotensions which are known to be deleterious for residual kidney function [34]. Similarly, when caring for an ESRD patient hospitalized for an acute condition, the prescription of fluid removal can be challenging for the clinician and IVC ultrasound could be useful to estimate CVP. In a recent observational study in 59 hospitalized hemodialysis patients, IVC measurements were accurate to predict high or low CVP but not adverse events during dialysis. The sample size was underpowered to detect a difference in the rate of intradialytic hypotension [35▪]. Finally, IVC ultrasound may be used in case of prolonged hemodynamic instability during hemodialysis where the finding of a dilated/fixed IVC should raise the suspicion of cardiogenic shock or pericardial tamponade [36]. This finding should prompt the clinician to perform a focused cardiac assessment as described in the next section, whereas a compliant/collapsed IVC suggests hypovolemic or distributive shock such as sepsis or anaphylaxis. The rapid identification of the mechanism of shock is of paramount importance as the time to identification and intervention is a major factor associated with improved outcomes [37,38].

Back to Top | Article Outline

FOCUSED CARDIAC ULTRASOUND IN END-STAGE RENAL DISEASE PATIENTS

Although performing detailed cardiac ultrasound requires advanced training, a focused cardiac ultrasound can be performed at the bedside in the context of hemodynamic instability to quickly detect life-threatening conditions. An examination using three basic views presented in Fig. 3 allows a rapid evaluation of the biventricular function and pericardial space. Consequently, the trained clinician can diagnose clinically significant pericardial effusions, acute left ventricular systolic dysfunction, and right ventricular dilatation.

FIGURE 3

FIGURE 3

With specialized training, it is also possible to detect dynamic abnormalities during dialysis which would not be detected during elective diagnostic echocardiography in the radiology department. Fluid removal may induce transient episodes of left ventricular outflow tract obstruction and mitral valve regurgitation by a systolic anterior motion of the mitral valve during the cardiac cycle [39–41]. Myocardial stunning, defined as new abnormal wall motion during or after dialysis, may identify patients with coronary artery disease suffering from repeated episodes of myocardial ischemia because of increased myocardial demands and decreased cardiac output during dialysis [42,43]. Additionally, another potentially useful application would be to monitor change in left atrial volume, a simple parameter strongly associated with cardiovascular risk in ESRD patients. Left atrial volume may be a better indicator of the clinical impact of concentric myocardial hypertrophy than the left ventricular mass index [44] and might also be useful in identifying patients with progressive left ventricular diastolic dysfunction and worsening mitral valvular disease [45].

Back to Top | Article Outline

ABDOMINAL ULTRASOUND IN END-STAGE RENAL DISEASE PATIENTS

The traditional applications of abdominal POCUS are multiple and out of scope of this review. In the nephrology clinic, renal and bladder ultrasound can be used to rule out urinary obstruction and should be the first step in the setting of a sudden reduction of residual urine output. Bladder ultrasound is a simple assessment and can reveal a full bladder suggestive of lower urinary tract obstruction in the setting of an acute reduction in urine output. Hydronephrosis can also be detected with basic training in renal ultrasound.

In the setting of varying degrees of right ventricular dysfunction and fluid overload, the impact of venous hypertension can be assessed using Doppler ultrasound of the liver vessels. When the CVP increases, the compliance of the IVC decreases and variation of right atrial pressure during the cardiac cycle can be transmitted to the portal circulation. This results in abnormal velocity variations during the cardiac cycle. A variation of blood flow velocity in the portal vein during the cardiac cycle superior to 50% is abnormal. This is often called portal pulsatile flow. Portal flow pulsatility has been associated with abnormal bilirubin in chronic heart failure patients suggestive of impairment of liver function because of venous congestion [46]. Similarly, other signs of abdominal organ congestion such as bowel edema can be detected by ultrasound and are associated with inflammation and cachexia in congestive heart failure patients [47]. Given the relationship between fluid overload, inflammation and adverse outcomes in ESRD patients, the effect of bowel congestion should be further investigated [48,49▪,50].

Back to Top | Article Outline

ULTRASOUND FOR VASCULAR ACCESS

Although the installation of permanent venous access is usually performed by radiologists in a controlled setting, temporary dialysis catheters can be installed by the nephrologist when rapid access to an interventional radiologist is not an option. Several trials have shown that the use of real-time ultrasound guidance for the installation of dialysis catheters reduces failure rate and complications [51]. Using ultrasound is enabling the clinician to evaluate the patency of the vein and guide the needle to avoid arterial puncture or pneumothorax, as presented in Fig. 4. Ultrasound guidance is recommended in anesthesiology [52], intensive care guidelines [53▪], and by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines on acute kidney injury [54]. Given the high grade evidence from randomized controlled trials, the use of real-time ultrasound guidance for dialysis catheter installation should be mandatory.

FIGURE 4

FIGURE 4

Ultrasound assessment has been used for the evaluation of arteriovenous fistula and grafts. Three potential applications can be identified: planning for fistula creation, assessing the maturation of the fistula, and identifying problems once used. The routine evaluation of native artery and veins before fistula creation has been studied in multiple trials and summarized in two meta-analyses demonstrating that this was not associated with improved fistula outcomes, except for a reduction in immediate failure rate [55,56]. A detailed evaluation is usually done by experienced radiologists, but this specialized skill may be acquired by an interventional nephrologist performing nonsurgical arteriovenous access creation. For the nephrologist involved in the care of dialysis patients, the decision to begin using a fistula and the troubleshooting of problems during the use of fistula are common occurrences for which POCUS is useful. Using a linear probe, the diameter, distance from the skin, and blood velocity can be assessed with basic training. The Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines on vascular access recommended that fistula maturation could be evaluated by the rule of six “a flow greater than 600 ml/min, a diameter at least 0.6 cm, no more than 0.6 cm deep, and discernible margins” [57]. All those features can be easily assessed in a matter of minutes using POCUS at the bedside and reassessed over time to determine the optimal timing to begin using the access. Additionally, POCUS can be used to reassess the access characteristics in the setting of dysfunction or asymptomatic reduction of blood flow though the access. Although preemptive correction of arteriovenous access stenosis is currently not associated with a significant reduction of access loss [58], a better knowledge of the vascular access anatomy may increase awareness and perhaps lead to a lower threshold for intervention in some patients. In the setting of an acute dysfunction, POCUS can quickly identify thrombosis as shown in Fig. 5.

FIGURE 5

FIGURE 5

Back to Top | Article Outline

CONCLUSION

The applications of POCUS in ESRD are multiple (Table 1). Basic POCUS training including IVC ultrasound [25], pulmonary ultrasound [59], and limited cardiac ultrasound [60] can be learned over a short period of time resulting in similar skill compared to specialized training. Moreover, training can be provided online with excellent results [61]. Although lung ultrasound has generated interest in the nephrology community, the potential impact of the widespread adoption of POCUS in the care of nephrology patients goes beyond this specific assessment. It may be challenging to prove that training nephrologists in POCUS will result in better outcomes in ESRD patients. However, as more clinicians diagnose life-threatening conditions with this tool, it may become impossible to convince them that their physical examination is complete without insonation. With basic curriculum now integrating POCUS in undergraduates [62▪], internal medicine [63▪], and nephrology training [64▪▪], a famous quote by Victor Hugo comes to mind: “You can resist an invading army; you cannot resist an idea whose time has come.”

Table 1

Table 1

Back to Top | Article Outline

Acknowledgements

We sincerely thank Denis Babin (Research Assistant) for his help in manuscript preparation.

Back to Top | Article Outline

Financial support and sponsorship

W.B.-S. receives salary support from Fonds de Recherche du Québec en Santé (FRQS). A.D. is supported by the Richard Kaufman Endowment Fund in Anesthesia and Critical Care and the Montreal Heart Institute Foundation.

Back to Top | Article Outline

Conflicts of interest

Dr André Denault is on the Speaker bureau for CAE Healthcare.

Back to Top | Article Outline

REFERENCES AND RECOMMENDED READING

Papers of particular interest, published within the annual period of review, have been highlighted as:

  • ▪ of special interest
  • ▪▪ of outstanding interest
Back to Top | Article Outline

REFERENCES

1. Torino C, Gargani L, Sicari R, et al. The agreement between auscultation and lung ultrasound in hemodialysis patients: the LUST study. Clin J Am Soc Nephrol 2016; 11:2005–2011.
2. Agarwal R, Andersen MJ, Pratt JH. On the importance of pedal edema in hemodialysis patients. Clin J Am Soc Nephrol 2008; 3:153–158.
3. Wabel P, Moissl U, Chamney P, et al. Towards improved cardiovascular management: the necessity of combining blood pressure and fluid overload. Nephrol Dial Transplant 2008; 23:2965–2971.
4▪▪. Narula J, Chandrashekhar YY, Braunwald E. Time to add a fifth pillar to bedside physical examination: inspection, palpation, percussion, auscultation, and insonation. JAMA Cardiology 2018; 3:346–350.

This article propose that point-of-care ultrasound should be included as a fifth component of physical examination and review how the recent innovation in miniaturization are now enabling the widespread adoption of this technology.

5. Sachdeva M, Ross DW, Shah HH. Renal ultrasound, dialysis catheter placement, and kidney biopsy experience of US nephrology fellows. Am J Kidney Dis 2016; 68:187–192.
6. Soldati G, Copetti R, Sher S. Sonographic interstitial syndrome: the sound of lung water. J Ultrasound Med 2009; 28:163–174.
7. Lichtenstein D, Meziere G, Biderman P, et al. The comet-tail artifact. An ultrasound sign of alveolar-interstitial syndrome. Am J Respir Crit Care Med 1997; 156:1640–1646.
8. Prosen G, Klemen P, Strnad M, Grmec S. Combination of lung ultrasound (a comet-tail sign) and N-terminal pro-brain natriuretic peptide in differentiating acute heart failure from chronic obstructive pulmonary disease and asthma as cause of acute dyspnea in prehospital emergency setting. Crit Care 2011; 15:R114.
9. Agricola E, Bove T, Oppizzi M, et al. Ultrasound comet-tail images: a marker of pulmonary edema: a comparative study with wedge pressure and extravascular lung water. Chest 2005; 127:1690–1695.
10. Mallamaci F, Benedetto FA, Tripepi R, et al. Detection of pulmonary congestion by chest ultrasound in dialysis patients. JACC Cardiovasc Imaging 2010; 3:586–594.
11. Panuccio V, Enia G, Tripepi R, et al. Chest ultrasound and hidden lung congestion in peritoneal dialysis patients. Nephrol Dial Transplant 2012; 27:3601–3605.
12. Noble VE, Murray AF, Capp R, et al. Ultrasound assessment for extravascular lung water in patients undergoing hemodialysis. Time course for resolution. Chest 2009; 135:1433–1439.
13▪. Beaubien-Souligny W, Rheaume M, Blondin MC, et al. A simplified approach to extravascular lung water assessment using point-of-care ultrasound in patients with end-stage chronic renal failure undergoing hemodialysis. Blood Purif 2017; 45 (1–3):79–87.

This prospective cohort study describes the change in B-line during hemodialysis and report the presence of B-lines in more than 21% of lung fields is highly predictive of hospitalization for heart failure.

14. Enia G, Torino C, Panuccio V, et al. Asymptomatic pulmonary congestion and physical functioning in hemodialysis patients. Clin J Am Soc Nephrol 2013; 8:1343–1348.
15. Zoccali C, Torino C, Tripepi R, et al. Pulmonary congestion predicts cardiac events and mortality in ESRD. J Am Soc Nephrol 2013; 24:639–646.
16. Siriopol D, Hogas S, Voroneanu L, et al. Predicting mortality in haemodialysis patients: a comparison between lung ultrasonography, bioimpedance data and echocardiography parameters. Nephrol Dial Transplant 2013; 28:2851–2859.
17. Siriopol D, Voroneanu L, Hogas S, et al. Bioimpedance analysis versus lung ultrasonography for optimal risk prediction in hemodialysis patients. Int J Cardiovasc Imaging 2016; 32:263–270.
18. Martindale JL, Wakai A, Collins SP, et al. Diagnosing acute heart failure in the emergency department: a systematic review and meta-analysis. Acad Emerg Med 2016; 23:223–242.
19. Judd E, Ahmed MI, Harms JC, et al. Pneumonia in hemodialysis patients: a challenging diagnosis in the emergency room. J Nephrol 2013; 26:1128–1135.
20. Bakirci T, Sasak G, Ozturk S, et al. Pleural effusion in long-term hemodialysis patients. Transplant Proc 2007; 39:889–891.
21. Staub LJ, Biscaro RR, Kaszubowski E, Maurici R. Chest ultrasonography for the emergency diagnosis of traumatic pneumothorax and haemothorax: a systematic review and meta-analysis. Injury 2018; 49:457–466.
22▪▪. Siriopol D, Onofriescu M, Voroneanu L, et al. Dry weight assessment by combined ultrasound and bioimpedance monitoring in low cardiovascular risk hemodialysis patients: a randomized controlled trial. Int Urol Nephrol 2017; 49:143–153.

The first randomized controlled trial on the use of pulmonary ultrasound to adjust target weight in hemodialysis patients.

23▪. Covic A, Ciumanghel AI, Siriopol D, et al. Value of bioimpedance analysis estimated ‘dry weight’ in maintenance dialysis patients: a systematic review and meta-analysis. Int Urol Nephrol 2017; 49:2231–2245.

This meta-analysis reports that the use of whole body bioimpedance to adjust target weight in hemodialysis patients is currently not associated with a reduction in mortality based on the available completed trials.

24. Reddan DN, Szczech LA, Hasselblad V, et al. Intradialytic blood volume monitoring in ambulatory hemodialysis patients: a randomized trial. J Am Soc Nephrol 2005; 16:2162–2169.
25. Muniz Pazeli J, Fagundes Vidigal D, Cestari Grossi T, et al. Can nephrologists use ultrasound to evaluate the inferior vena cava? A cross-sectional study of the agreement between a nephrologist and a cardiologist. Nephron Extra 2014; 4:82–88.
26. Stawicki SP, Braslow BM, Panebianco NL, et al. Intensivist use of hand-carried ultrasonography to measure IVC collapsibility in estimating intravascular volume status: correlations with CVP. J Am Coll Surg 2009; 209:55–61.
27. Kircher BJ, Himelman RB, Schiller NB. Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava. Am J Cardiol 1990; 66:493–496.
28. Rudski LG, Lai WW, Afilalo J, et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr 2010; 23:685–713.
29▪. Seo Y, Iida N, Yamamoto M, et al. Estimation of central venous pressure using the ratio of short to long diameter from cross-sectional images of the inferior vena cava. J Am Soc Echocardiogr 2017; 30:461–467.

This study observed that a ratio between the short diameter and the long diameter of the IVC of more than 0.69 is predictive of a high CVP (≥10 mmHg)

30. Agarwal R, Alborzi P, Satyan S, Light RP. Dry-weight reduction in hypertensive hemodialysis patients (DRIP): a randomized, controlled trial. Hypertension 2009; 53:500–507.
31. Agarwal R, Bouldin JM, Light RP, Garg A. Inferior vena cava diameter and left atrial diameter measure volume but not dry weight. Clin J Am Soc Nephrol 2011; 6:1066–1072.
32. Torterue X, Dehoux L, Macher MA, et al. Fluid status evaluation by inferior vena cava diameter and bioimpedance spectroscopy in pediatric chronic hemodialysis. BMC Nephrol 2017; 18:373.
33. Sakurai T, Ando Y, Masunaga Y, et al. Diameter of the inferior vena cava as an index of dry weight in patients undergoing CAPD. Perit Dial Int 1996; 16:183–185.
34. Jansen MA, Hart AA, Korevaar JC, et al. Predictors of the rate of decline of residual renal function in incident dialysis patients. Kidney Int 2002; 62:1046–1053.
35▪. Sekiguchi H, Seaburg LA, Suzuki J, et al. Central venous pressure and ultrasonographic measurement correlation and their associations with intradialytic adverse events in hospitalized patients: A prospective observational study. J Crit Care 2018; 44:168–174.

This study shows that IVC ultrasound in hospitalized patients requiring hemodialysis can adequately discriminate between low and high CVP.

36. Vegas A, Denault A, Royse C. A bedside clinical and ultrasound-based approach to hemodynamic instability - part II: bedside ultrasound in hemodynamic shock: continuing professional development. Can J Anaesth 2014; 61:1008–1027.
37. Kumar A, Roberts D, Wood KE, et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med 2006; 34:1589–1596.
38. Hochman JS, Sleeper LA, Webb JG, et al. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. N Engl J Med 1999; 341:625–634.
39. Straumann E, Bertel O, Meyer B, et al. Symmetric and asymmetric left ventricular hypertrophy in patients with end-stage renal failure on long-term hemodialysis. Clin Cardiol 1998; 21:672–678.
40. Canivet JL, Lancellotti P, Radermecker M, Damas P. Cyclic appearance of left ventricular outflow tract dynamic obstruction during mechanical ventilation: evidence for a preload dependent phenomenon. J Intensive Care Med 2008; 23:281–284.
41. Dimitrow PP, Michałowska J, Sorysz D. The effect of hemodialysis on left ventricular outflow tract gradient. Echocardiography 2010; 27:603–607.
42. McIntyre CW, Salerno FR. Diagnosis and treatment of intradialytic hypotension in maintenance hemodialysis patients. Clin J Am Soc Nephrol 2018; 13:486–489.
43. McIntyre CW, Harrison LE, Eldehni MT, et al. Circulating endotoxemia: a novel factor in systemic inflammation and cardiovascular disease in chronic kidney disease. Clin J Am Soc Nephrol 2011; 6:133–141.
44. Tripepi G, Benedetto FA, Mallamaci F, et al. Left atrial volume monitoring and cardiovascular risk in patients with end-stage renal disease: a prospective cohort study. J Am Soc Nephrol 2007; 18:1316–1322.
45. Di Lullo L, Floccari F, Granata A, et al. Dyspnea in hemodialysis and early echocardiographic examination at the bedside: two case reports. J Ultrasound 2011; 14:110–112.
46. Styczynski G, Milewska A, Marczewska M, et al. Echocardiographic correlates of abnormal liver tests in patients with exacerbation of chronic heart failure. J Am Soc Echocardiogr 2016; 29:132–139.
47. Valentova M, von Haehling S, Bauditz J, et al. Intestinal congestion and right ventricular dysfunction: a link with appetite loss, inflammation, and cachexia in chronic heart failure. Eur Heart J 2016; 37:1684–1691.
48. Antlanger M, Hecking M, Haidinger M, et al. Fluid overload in hemodialysis patients: a cross-sectional study to determine its association with cardiac biomarkers and nutritional status. BMC Nephrol 2013; 14:266.
49▪. Dekker MJ, Marcelli D, Canaud BJ, et al. Impact of fluid status and inflammation and their interaction on survival: a study in an international hemodialysis patient cohort. Kidney Int 2017; 91:1214–1223.

This study demonstrates an association between fluid overload and chronic inflammation in hemodialysis patients.

50. Goncalves S, Pecoits-Filho R, Perreto S, et al. Associations between renal function, volume status and endotoxaemia in chronic kidney disease patients. Nephrol Dial Transplant 2006; 21:2788–2794.
51. Rabindranath KS, Kumar E, Shail R, Vaux E. Use of real-time ultrasound guidance for the placement of hemodialysis catheters: a systematic review and meta-analysis of randomized controlled trials. Am J Kidney Dis 2011; 58:964–970.
52. Rupp SM, Apfelbaum JL, Blitt C, et al. American Society of Anesthesiologists Task Force on Central Venous Access. Practice guidelines for central venous access: a report by the American Society of Anesthesiologists Task Force on Central Venous Access. Anesthesiology 2012; 116:539–573.
53▪. Saugel B, Scheeren TWL, Teboul J-L. Ultrasound-guided central venous catheter placement: a structured review and recommendations for clinical practice. Crit Care 2017; 21:225.

Current recommendations for central venous catheter placement suggesting that the use of real-time ultrasound guidance is preferred.

54. Kidney Disease: Improving Global Outcomes (KDIGO) Acute Kidney Injury Work Group. KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int 2012; 2:1–138. Suppl.
55. Kosa SD, Al-Jaishi AA, Moist L, Lok CE. Preoperative vascular access evaluation for haemodialysis patients. Cochrane Database Syst Rev 2015; CD007013.
56. Georgiadis GS, Charalampidis DG, Argyriou C, et al. The necessity for routine preoperative ultrasound mapping before arteriovenous fistula creation: a meta-analysis. Eur J Vasc Endovasc Surg 2015; 49:600–605.
57. Vascular Access 2006 Work Group. Clinical practice guidelines for vascular access. Am J Kidney Dis 2006; 48 (Suppl 1):S176–S247.
58. Ravani P, Quinn RR, Oliver MJ, et al. Preemptive correction of arteriovenous access stenosis: a systematic review and meta-analysis of randomized controlled trials. Am J Kidney Dis 2016; 67:446–460.
59. Chiem AT, Chan CH, Ander DS, et al. Comparison of expert and novice sonographers’ performance in focused lung ultrasonography in dyspnea (FLUID) to diagnose patients with acute heart failure syndrome. Acad Emerg Med 2015; 22:564–573.
60. Beraud AS, Rizk NW, Pearl RG, et al. Focused transthoracic echocardiography during critical care medicine training: curriculum implementation and evaluation of proficiency. Crit Care Med 2013; 41:e179–e181.
61. Gargani L, Sicari R, Raciti M, et al. Efficacy of a remote web-based lung ultrasound training for nephrologists and cardiologists: a LUST trial sub-project. Nephrol Dial Transplant 2016; 31:1982–1988.
62▪. Johri AM, Durbin J, Newbigging J, et al. Cardiac point-of-care ultrasound: state of the art in medical school education. J Am Soc Echocardiogr 2018; 31:749–760.

This article describes how point-of-care ultrasound has been integrated into basic curriculum in undergraduate medical studies and how this experience may enhance learning.

63▪. Ma IW, Arishenkoff S, Wiseman J, et al. Internal medicine point-of-care ultrasound curriculum: consensus recommendations from the Canadian Internal Medicine Ultrasound (CIMUS) Group. J Gen Intern Med 2017; 32:1052–1057.

Current Canadian recommendations of POCUS curriculum adapted to the practice of general internal medicine.

64▪▪. Mullangi S, Sozio SM, Segal P, et al. Point-of-care ultrasound education to improve care of dialysis patients. Semin Dial 2018; 31:154–162.

This article describes that POCUS has been integrated into the nephrology curriculum at John Hopkins.

65. Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med 2012; 38:577–591.
66. Taylor and Francis, CRC Press, Denault AY, Vegas A, Lamarche CP, et al. Basic transesophageal and critical care ultrasound. 2018.
    Keywords:

    dialysis; end-stage renal disease; fluid balance management; point-of-care ultrasound

    Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.