Use of point-of-care ultrasound (POCUS) to monitor neonatal and pediatric extracorporeal life support

Extracorporeal membrane oxygenation (ECMO) is an invasive life support technique that requires a blood pump, an artificial membrane lung, and vascular cannulae to drain de-oxygenated blood, remove carbon dioxide, oxygenate, and return it to the patient. ECMO is generally used to provide advanced and prolonged cardiopulmonary support in patients with refractory acute cardiac and/or respiratory failure. After its first use in 1975 to manage a severe form of meconium aspiration syndrome with resultant pulmonary hypertension, the following years were dominated by the use of ECMO to manage neonatal respiratory failure and limited to a few centers across the world. In the 1990s, evidence for neonatal respiratory ECMO support increased; however, the number of cases began to decline with the use of newer pharmacologic therapies (e.g., inhaled nitric oxide, exogenous surfactant, and high-frequency oscillatory ventilation). On the contrary, pediatric ECMO sustained steady growth. Combined advances in ECMO technology and bedside medical management have improved general outcomes, although ECMO-related complications remain challenging. Point-of-care ultrasound (POCUS) is an essential tool to monitor all phases of neonatal and pediatric ECMO: evaluation of ECMO candidacy, ultrasound-guided ECMO cannulation, daily evaluation of heart and lung function and brain perfusion, detection and management of major complications, and weaning from ECMO support.  Conclusion: Based on these considerations and on the lack of specific guidelines for the use of POCUS in the neonatal and pediatric ECMO setting, the aim of this paper is to provide a systematic overview for the application of POCUS during ECMO support in these populations. What is Known: • Extracorporeal membrane oxygenation (ECMO) provides advanced cardiopulmonary support for patients with refractory acute cardiac and/or respiratory failure and requires appropriate monitoring. • Point-of-care ultrasound (POCUS) is an accessible and adaptable tool to assess neonatal and pediatric cardiac and/or respiratory failure at bedside. What is New: • In this review, we discussed the use of POCUS to monitor and manage at bedside neonatal and pediatric patients supported with ECMO. • We explored the potential use of POCUS during all phases of ECMO support: pre-ECMO assessment, ECMO candidacy evaluation, daily evaluation of heart, lung and brain function, detection and troubleshooting of major complications, and weaning from ECMO support.

Combined extracorporeal CO2 removal and renal replacement therapy in a pregnant patient with COVID-19: a case report

Background. Pregnant women are at high risk of Coronavirus disease 2019 (COVID-19) complications, including acute respiratory distress syndrome. Currently, one of the cornerstones in the treatment of this condition is lung-protective ventilation (LPV) with low tidal volumes. However, the occurrence of hypercapnia may limit this ventilatory strategy. So, different extracorporeal CO2 removal (ECCO2R) procedures have been developed. ECCO2R comprises a variety of techniques, including low-flow and high-flow systems, that may be performed with dedicated devices or combined with continuous renal replacement therapy (CRRT). Case description. Here, we report a unique case of a pregnant patient affected by COVID-19 who required extracorporeal support for multiorgan failure. While on LPV, because of the concomitant hypercapnia and acute kidney injury, the patient was treated with an ECCO2R membrane inserted in series after a hemofilter in a CRRT platform. This combined treatment reducing hypercapnia allowed LPV maintenance at the same time while providing kidney replacement and ensuring maternal and fetal hemodynamic stability. Adverse effects consisted of minor bleeding episodes due to the anticoagulation required to maintain the extracorporeal circuit patency. The patient's pulmonary and kidney function progressively recovered, permitting the withdrawal of any extracorporeal treatment. At the 25th gestational week, the patient underwent spontaneous premature vaginal delivery because of placental abruption. She gave birth to an 800-gram female baby, who three days later died because of multiorgan failure related to extreme prematurity. Conclusions. This case supports using ECCO2R-CRRT combined treatment as a suitable approach in the management of complex conditions, such as pregnancy, even in the case of severe COVID-19.

Renal Outcomes of Dialysis-Dependent Acute Kidney Injury in Noncritically Ill Patients: A Retrospective Study

INTRODUCTION

Acute kidney injury (AKI) is a common complication among hospitalized patients, potentially affecting short- and long-term clinical outcomes. In this retrospective study, we evaluated renal outcomes in noncritically ill patients who required acute hemodialysis (HD) because of an AKI episode occurring during hospitalization.

METHODS

Sixty-three hemodynamically stable patients with AKI undergoing acute intermittent HD were included. Kidney function was evaluated at baseline control (pre-AKI), at AKI diagnosis and during the follow-up. According to serum creatinine and the estimated glomerular filtration rate (eGFR), we defined three clinical conditions: renal recovery, different stages of acute kidney disease (AKD), and chronic kidney disease (CKD).

RESULTS

Among the 63 patients evaluated, 34 patients (54%) had a history of CKD. Six patients (10%) presented early full renal recovery. HD treatment was stopped in 38 patients (60%), while 25 patients (40%) required maintenance HD. Dialysis-independent patients presented lower comorbidity and higher baseline eGFR and delta creatinine, compared to dialysis-dependent patients. Baseline CKD, previous AKI episodes, and parenchymal causes of AKI were associated with a significant risk of dialysis dependence. At 1-month control, 15 patients (39%) presented AKD stage 0, 6 patients (16%) AKD stage 1, and 17 patients (44%) AKD stage 2-3. At 3-month control, 29 out of 38 patients recovering from AKI (76%) presented CKD. AKD stage was significantly correlated with the risk of CKD development, which, resulted higher in patients with lower baseline eGFR.

CONCLUSIONS

AKI might represent a risk factor for the development of chronic kidney damage, even in noncritically ill patients.

Effect of Levosimendan Treatment in Pediatric Patients With Cardiac Dysfunction: An Update of a Systematic Review and Meta-Analysis of Randomized Controlled Trials

Levosimendan increasingly has been used to treat heart failure and cardiac dysfunction in pediatric patients. Currently, there is only limited evidence that this drug positively affects outcomes. The authors' aim was to investigate the effects of levosimendan on hemodynamic parameters and outcomes in pediatric patients in all clinical settings. The study design was a systematic review of randomized and nonrandomized studies. Randomized clinical trials (RCTs) were included in a meta-analysis. The primary outcome of the meta-analysis was the effect of levosimendan on central venous oxygen saturation (ScvO₂) and lactate values as surrogate markers of low-cardiac-output syndrome. The study setting was any acute care setting. Study participants were pediatric patients (age <18 years) receiving levosimendan, and the intervention was levosimendan versus any control treatment. The authors identified 44 studies published from 2004 to 2020, including a total of 1,131 pediatric patients. Nine studies (enrolling 547 patients) were RCTs, all performed in a pediatric cardiac surgery setting. Three RCTs were judged to carry a low risk of bias. In the RCTs, levosimendan administration was associated with a significant improvement of ScvO₂ (p = 0.03) and a trend toward lower postoperative lactate levels (p = 0.08). No differences could be found for secondary outcomes. Levosimendan use in pediatric patients is not associated with major side effects and may lead to hemodynamic improvement after cardiac surgery. However, its impact on major clinical outcomes remains to be determined. Overall, the quality of evidence for levosimendan use in pediatric patients is low, and further high-quality RCTs are needed.

Hyperkalemia-induced acute flaccid paralysis: a case report

Acute flaccid paralysis is a medical emergency that may be caused by primary neuro-muscular disorders, metabolic alterations, and iatrogenic effects. Severe hyperkalemia is also a potential cause, especially in elderly patients with impaired renal function. Early diagnosis is essential for appropriate management. Here, we report the case of a 78-year-old woman with hypertension and diabetes presenting to the emergency department because of pronounced asthenia, rapidly evolving in quadriparesis. Laboratory examinations showed severe hyperkalemia of 9.9 mmol/L, metabolic acidosis, kidney failure (creatinine 1.6 mg/dl), and hyperglycemia (501 mg/dl). The electrocardiography showed absent P-wave, widening QRS, and tall T-waves. The patient was immediately treated with medical therapy and a hemodialysis session, presenting a rapid resolution of electrocardiographic and neurological abnormalities. This case offers the opportunity to discuss the pathogenesis, the clinical presentation, and the management of hyperkalemia-induced acute flaccid paralysis.

Neutrophil gelatinase-associated lipocalin does not predict acute kidney injury in heart failure

BACKGROUND

Acute cardiorenal syndrome type 1 (CRS-1) is defined by a rapid cardiac dysfunction leading to acute kidney injury (AKI). Neutrophil gelatinase-associated lipocalin (NGAL) is expressed on the surface of human neutrophils and epithelial cells, such as renal tubule cells, and its serum (sNGAL) and urinary have been used to predict AKI in different clinical settings.

AIM

To characterize CRS-1 in a cohort of patients with acute heart diseases, evaluating the potentiality of sNGAL as an early marker of CRS-1.

METHODS

We performed a retrospective cohort, multi-centre study. From January 2010 to December 2011, we recruited 202 adult patients admitted to the coronary intensive care unit (CICU) with a diagnosis of acute heart failure or acute coronary syndrome. We monitored the renal function to evaluate CRS-1 development and measured sNGAL levels within 24 h and after 72 h of CICU admission.

RESULTS

Overall, enrolled patients were hemodynamically stable with a mean arterial pressure of 92 (82-107) mmHg, 55/202 (27.2%) of the patients developed CRS-1, but none of them required dialysis. Neither the NGAL delta value (AUC 0.40, 95%CI: 0.25-0.55) nor the NGAL peak (AUC 0.45, 95%CI: 0.36-0.54) or NGAL cut-off (≥ 140 ng/mL) values were statistically significant between the two groups (CRS-1 vs no-CRS1 patients). The area under the ROC curve for the prediction of CRS-1 was 0.40 (95%CI: 0.25-0.55) for the delta NGAL value and 0.45 (95%CI: 0.36-0.54) for the NGAL peak value. Finally, in multivariate analysis, the risk of developing CRS-1 was correlated with age > 60 years, urea nitrogen at admission and 24 h-urine output (AUC 0.83, SE = 60.5% SP = 93%), while sNGAL was not significantly correlated.

CONCLUSION

In our population, sNGAL does not predict CRS-1, probably as a consequence of the mild renal injury and the low severity of heart disease. So, these data might suggest that patient selection should be taken into account when considering the utility of NGAL measurement as a biomarker of kidney damage.

[Spontaneous rupture of a simple renal cyst: clinical management]

Spontaneous renal bleeding mainly occurs in patients with polycystic kidney diseases or cancer. Indeed, despite the high prevalence of simple cysts, their spontaneous atraumatic rupture is a rare event. Underlying mechanisms may involve the increase of intracystic pressure and/or the development of a haemorrhage into the cyst. Management of this condition includes surgery, interventional radiology or conservative strategies. Here, we report a case of spontaneous rupture of a simple renal cyst, successfully managed with conservative treatment.

In vivo calibration of esophageal pressure in the mechanically ventilated patient makes measurements reliable

Background

Esophageal pressure (Pes) can provide information to guide mechanical ventilation in acute respiratory failure. However, both relative changes and absolute values of Pes can be affected by inappropriate filling of the esophageal balloon and by the elastance of the esophagus wall. We evaluated the feasibility and effectiveness of a calibration procedure consisting in optimization of balloon filling and subtraction of the pressure generated by the esophagus wall (Pew).

Methods

An esophageal balloon was progressively filled in 36 patients under controlled mechanical ventilation. V_BEST was the filling volume associated with the largest tidal increase of Pes. Esophageal wall elastance was quantified and Pew was computed at each filling volume. Different filling strategies were compared by performing a validation occlusion test.

Results

Fifty series of measurements were performed. V_BEST was 3.5 ± 1.9 ml (range 0.5–6.0). Esophagus elastance was 1.1 ± 0.5 cmH₂O/ml (0.3–3.1). Both Pew and the result of the occlusion test differed among filling strategies. At filling volumes of 0.5, V_BEST and 4.0 ml respectively, Pew was 0.0 ± 0.1, 2.0 ± 1.9, and 3.0 ± 1.7 cmH₂O (p < 0.0001), whereas the occlusion test was satisfactory in 22 %, 98 %, and 88 % of cases (p < 0.0001).

Conclusions

Under mechanical ventilation, an increase of balloon filling above the conventionally recommended low volumes warrants complete transmission of Pes swings, but is associated with significant elevation of baseline. A simple calibration procedure allows finding the filling volume associated with the best transmission of tidal Pes change and subtracting the associated baseline artifact, thus making measurement of absolute values of Pes reliable.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1278-5) contains supplementary material, which is available to authorized users.

Renal involvement in mushroom poisoning: The case of Orellanus syndrome

Although mushroom poisoning is a rare cause of acute renal injury, in some cases it may lead to the development of a severe and irreversible renal failure. Orellanus syndrome is the most important example of organic renal damage related to mushroom consumption. It is caused by the ingestion of orellanine, the main toxin of different types of Cortinarius mushrooms (Cortinarius speciosissimus, C. orellanus, C. orellanoides, etc.), and it is characterized by progressive clinical phases with a predominant kidney involvement, finally requiring renal replacement therapy in about 10% of cases. Renal damage is often late and associated with a histological picture of interstitial nephritis. Diagnosis is essentially clinical and no specific therapy has been shown to be effective in preventing and treating renal damage. Here, we describe the case of a patient with mixed wild mushroom poisoning, presenting the typical clinical signs and course of the Orellanus syndrome. This case offers us the opportunity to review the main clinical features of this severe and little-known intoxication.

Esophageal pressure measurements under different conditions of intrathoracic pressure. An in vitro study of second generation balloon catheters

BACKGROUND

The aim of this study was to evaluate in vitro the accuracy of second generation esophageal catheters at different surrounding pressures and filling volumes and to suggest appropriate catheter management in clinical practice.

METHODS

Six different esophageal catheters were placed in an experimental chamber at four chamber pressures (0, 10, 20 and 30 cmH2O) and at filling volumes ranging from 0 to 10 mL. The working volume was defined as the volume range between the maximum (Vmax) and minimum (Vmin) volumes achieving acceptable accuracy (defined by a balloon transmural pressure ± 1 cmH2O). Accuracy was evaluated for a standard volume of 0.5 mL and for volumes recommended by manufacturers. Data are shown as median and interquartile range.

RESULTS

In the four conditions of chamber pressure Vmin, Vmax and working volume were 1.0 (0.5, 1.5), 5.3 (3.8, 7.1), and 3.5 (2.9, 6.1) mL. Increasing chamber pressure increased Vmin (rho=0.9; P<0.0001), that reached 2.0 mL (1.6-2.0) at 30 cmH2O. Vmax and working volumes differed among catheters, whereas Vmin did not. By injecting 0.5 mL and the minimum recommended volume by manufacturer, balloon transmural pressure was <-1 cmH2O in 71% and 53% of cases, it was negatively related to chamber pressure (rho=-0.97 and -0.71; P<0.0001) and reached values of -10.4 (-12.4, -9.7) and -9.8 (-10.6, -3.4) at 30 cmH2O.

CONCLUSION

Measuring positive esophageal pressures needs higher injected volumes than usually recommended. The range of appropriate filling volumes is catheter-specific. Both absolute values and respiratory changes of esophageal pressure can be underestimated by an underfilled balloon.

Multiple electrolyte disorders in a neurosurgical patient: solving the rebus

BACKGROUND

It is important to ensure an adequate sodium and volume balance in neurosurgical patients in order to avoid the worsening of brain injury.Indeed, hyponatremia and polyuria, that are frequent in this patient population, are potentially harmful, especially if not promptly recognized.Differential diagnosis is often challenging, including disorders, which, in view of similar clinical pictures, present very different pathophysiological bases, such as syndrome of inappropriate antidiuresis, cerebral/renal salt wasting syndrome and diabetes insipidus.

CASE PRESENTATION

Here we present the clinical report of a 67-year-old man with a recent episode of acute subarachnoid haemorrhage, admitted to our ward because of severe hyponatremia, hypokalemia and huge polyuria.We performed a complete workup to identify the underlying causes of these alterations and found a complex picture of salt wasting syndrome associated to primary polydipsia. The appropriate diagnosis allowed us to correct the patient hydro-electrolyte balance.

CONCLUSION

The comprehension of the pathophysiological mechanisms is essential to adequately recognize and treat hydro-electrolyte disorders, also solving the most complex clinical problems.

Mechanisms underlying sCD40 production in hemodialysis patients

CD40 and its ligand (CD40L) regulate several cellular functions, including T and B-cell activation. The soluble form of CD40 (sCD40) antagonizes CD40/CD40L interaction. Patients undergoing hemodialysis (HD) present elevated sCD40 serum levels, which underlying molecular mechanisms are unknown. We studied sCD40 serum and urinary levels, CD40 membrane and gene expression and membrane shedding in HD, uremic not-HD patients (UR) and healthy subjects (N). We found that in HD sCD40 serum levels were higher than UR and N, being significantly elevated in anuric patients, and that sCD40 correlated to renal function in UR subjects, who presented also a reduced sCD40 urinary excretion rate. HD and UR presented reduced CD40 membrane and gene expression. The concentration of TNF-α converting enzyme (TACE), responsible for CD40 cleavage was not different between HD and N. Therefore the reduced renal clearance is the main cause of elevated sCD40 levels in HD. This finding could have relevant clinical implications.

The syndrome of inappropriate antidiuresis: pathophysiology, clinical management and new therapeutic options

Hyponatremia is a marker of different underlying diseases and it can be a cause of morbidity itself; this implies the importance of a correct approach to the problem. The syndrome of inappropriate antidiuresis (SIAD) is one of the most common causes of hyponatremia: it is a disorder of sodium and water balance characterized by urinary dilution impairment and hypotonic hyponatremia, in the absence of renal disease or any identifiable non-osmotic stimulus able to induce antidiuretic hormone (ADH) release; according to its definition, it is diagnosed through an exclusion algorithm. SIAD is usually observed in hospitalized patients and its prevalence may be as high as 35%. The understanding of the syndrome has notably evolved over the last years, as reflected by the significant change in the name, once the syndrome of inappropriate secretion of ADH (SIADH), today SIAD. This review is up to date and it analyses the newest notions about pathophysiological mechanisms, classification, management and therapy of SIAD, including vaptans.