Letters to the Editor

LLC (funding for participation in the original trial on which this editorial was written), and U.S. FDA Office of Orphan Product Development Grant Program (Dr. Tamburro receives salary support from the U.S. FDA Office of Orphan Product Development Grant program for serving as a co-principal investigator of a clinical trial of calfactant). Dr. Truemper consulted for the Nebraska Society for Respiratory Care, received support for travel from Nebraska Society for Respiratory Care (included travel expenses in honorarium), is employed by Children’s Specialty Physicians, lectured for Nebraska Society for Respiratory Care, and received support for travel from Pneuma Pharmaceuticals. His institution received grant support from the University of Nebraska College of Medicine. He and his institution received grant support from Pneuma Pharmaceuticals. Dr. Truwit received royalties from Wiley Publishers (Mech Vent Textbook) and received grant support from National Institute of Health National Heart Lung, and Blood Institute-Acute Respiratory Distress Syndrome (ARDS) and Astra Zeneca-ARDS. His institution received grant support from Pneumo Partners. Dr. Traul received grant support from Pneuma Pharmaceuticals. Her institution received support for travel from Pneuma Pharmaceuticals. Dr. Egan disclosed being an owner and Chairman & Chief Medical Officer of ONY (ONY sponsored study), is employed by ONY, provided expert testimony for malpractice insurance companies, and has stock options with ONY (Part owner). The remaining authors have disclosed that they do not have any potential conflicts of interest. Douglas F. Willson, MD, Division of Pediatric Critical Care, Children’s Hospital of Richmond, Richmond, VA; Neal J. Thomas, MD, MSc, Robert Tamburro, MD, MSC, Division of Pediatric Critical Care, Penn State Hershey Children’s Hospital, Hershey, PA; Edward Truemper, MD, Division of Pediatric Critical Care, Children’s Hospital and Medical Center, University of Nebraska, Omaha, NE; Jonathon Truwit, MD, MBA, Department of Internal Medicine, University of Virginia, Charlottesville, VA; Mark Conaway, PhD, Department of Public Health Sciences, University of Virginia, Charlottesville, VA; Christine Traul, MD, MBA, Department of Pediatrics, Children’s Hospital Cleveland Clinic, Cleveland, OH; Edmund E. Egan, MD, ONY Pharmaceuticals, Amherst, NY, and Division of Neonatology at the State University of New York, Buffalo, NY

REFERENCES

1. Bhatia R, Penfil S: Calfactant: Is There a Potential Role in Acute Lung Injury? Pediatr Crit Care Med 2014; 15:385 2. Willson DF, Thomas NJ, Tamburro R, et  al: Pediatric calfactant in acute respiratory distress syndrome trial. Pediatr Crit Care Med 2013; 14:657–665 3. Willson DF, Jiao JH, Bauman LA, et al: Calf’s lung surfactant extract in acute hypoxemic respiratory failure in children. Crit Care Med 1996; 24:1316–1322 4. Willson DF, Bauman LA, Zaritsky A, et  al: Instillation of calf’s lung surfactant extract (Infasurf) is beneficial in pediatric acute hypoxemic respiratory failure. Crit Care Med 1999; 27:188–195 5. Willson DF, Thomas NJ, Markovitz BM, et al: Effect of exogenous surfactant in pediatric acute lung injury: A randomized, controlled trial. JAMA 2005; 293:470–476 DOI: 10.1097/PCC.0000000000000094

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Bedside Echocardiography for Pediatric Hemodynamic Monitoring: What Is the Impact in the Outcome? To the Editor:

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n a recent article in Pediatric Critical Care Medicine, the study by Ranjit et al (1) highlights the use of bedside echocardiography (ECHO) as a hemodynamic monitoring tool in the critically ill children, where the devices available for this purpose are limited and the use of noninvasive monitoring is more indicated. The study in question was conducted with the first author or an ECHO technician performing the echocardiographs at the bedside and Ranjit et al (1) state that was fully trained for this purpose, but this training is nowhere mentioned. As ECHO is an investigator-dependent test, there is a literature consensus that inadequate training can lead to inappropriate assessment and consequently improper therapy (2). Thus, a number of recent studies have been designed with the purpose to delineate a training course to enable intensivists and emergency department physicians to perform bedside ECHO (3, 4). So it seems clear to us that the author’s ECHO training program should be mentioned in this or other previous study of the group. Furthermore, what we think that it is still more important and interesting is the existence of a team of trained intensivists, which may be available full time in the ICU to perform ECHO at patient’s admission and then accomplish seriates evaluations, since the availability of only one intensivist enabled for the ECHO reproduces the same problem related to restrict availability of echocardiographers in ICU. The current study does not mention the presence of any other skilled physician at the ICU, besides the author. Regarding the echocardiographic assessments of emergency examination, it has already been established that the most important variables to be evaluated by ECHO are the ones about the blood volume status, left ventricular systolic function, and pericardial effusion/cardiac tamponade (5). However, the assessment of volume status by ECHO is a controversial topic. The respiratory diameter variation of the inferior vena cava (IVC), as the way it was presented by Ranjit et al (1), depends on the presence of spontaneous breathing versus positive pressure ventilation. The classification of patient as volume responsive when IVC respiratory variation is above 50% was performed in this study and used by Pershad et al (6) as reference; however, the last one was performed with half of the patients breathing spontaneously and this was not used as a therapeutic guide. The data from the study by Pershad et al (6) differs dramatically from those found in the study by Ranjit et al (1), where 87% of patients were on mechanical ventilation. The literature does not provide data about values of IVC diameter variability for mechanically ventilated children; however, an important study suggest a lower cutoff for mechanical ventilated adult patients (under or above 18%) to discriminate individuals responsiveness and unresponsiveness to fluid resuscitation with sensibility and also specificity of 90% (7). May 2014 • Volume 15 • Number 4

Letters to the Editor

For these reasons, we think that this topic should be discussed further by Ranjit et al (1). This is an interesting observational study, but this design does not allow answering an important question: How would be the management and outcome of these patients if ECHO was not performed? To answer this question, we think that is indispensable a prospective study with children, along the same model by Bouferrache et al (8), comparing the management and outcome of children with septic shock when the treatment protocol proposed by the surviving sepsis campaign is guided by the usual hemodynamic and when the same treatment protocol is guided by usual hemodynamic monitoring plus bedside ECHO. The authors have disclosed that they do not have any potential conflicts of interest. Heloisa Amaral Gaspar, MD, Patricia Leão Tuma, MD, Werther Brunow Carvalho, PhD, Artur Figueredo Delgado, PhD, Pediatric Critical Care Department, Instituto da Criança da Faculdade de Medicina, São Paulo University, Sao Paulo, Brazil

REFERENCES

1. Ranjit S, Aram G, Kissoon N, et  al: Multimodal Monitoring for Hemodynamic Categorization and Management of Pediatric Septic Shock: A Pilot Observational Study. Pediatr Crit Care Med 2014; 15:e17–e26 2. Labovitz AJ, Noble VE, Bierig M, et  al: Focused cardiac ultrasound in the emergent setting: A consensus statement of the American Society of Echocardiography and American College of Emergency Physicians. J Am Soc Echocardiogr 2010; 23:1225–1230 3. Vignon P, Dugard A, Abraham J, et al: Focused training for ­goal-oriented hand-held echocardiography performed by noncardiologist residents in the intensive care unit. Intensive Care Med 2007; 33:1795–1799 4. Vignon P, Mücke F, Bellec F, et al: Basic critical care echocardiography: Validation of a curriculum dedicated to noncardiologist residents. Crit Care Med 2011; 39:636–642 5. Mayo PH, Beaulieu Y, Doelken P, et al: American College of Chest Physicians/La Société de Réanimation de Langue Française statement on competence in critical care ultrasonography. Chest 2009; 135:1050–1060 6. Pershad J, Myers S, Plouman C, et al: Bedside limited echocardiography by the emergency physician is accurate during evaluation of the critically ill patient. Pediatrics 2004; 114:e667–e671 7. Barbier C, Loubières Y, Schmit C, et al: Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients. Intensive Care Med 2004; 30:1740–1746 8. Bouferrache K, Amiel JB, Chimot L, et al: Initial resuscitation guided by the Surviving Sepsis Campaign recommendations and early echocardiographic assessment of hemodynamics in intensive care unit septic patients: A pilot study. Crit Care Med 2012; 40:2821–2827 DOI: 10.1097/PCC.0000000000000081

The authors reply:

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e appreciate the insightful comments of Gaspar et al (1) regarding our article (2) describing the use of echocardiography (ECHO) to complement standard monitoring tools in the assessment of children with septic shock. They asked whether a team of ECHO-experienced PICU staff would be more useful than the first author (S.R.), along with cardiology staff performing all the ECHO examinations. However, the study design did not allow for this approach. In Pediatric Critical Care Medicine

our study, the first author (S.R.) performed the majority of the studies, and a cardiology-trained personnel performed the rest. Although our PICU does have many ECHO-trained personnel, we deliberately chose to limit the personnel performing the studies to minimize the possibility of interobserver variability. The second query was the extent of training that is necessary to obtain adequate skills in focused bedside ECHO by ICU personnel, who essentially have noncardiology, nonradiology backgrounds. The relevance of adequate training becomes even more important as ECHO and ultrasonography are observer dependent, especially with respect to image quality acquisition and interpretation of data. The training by the first author was extensive and included enrollment to two separate 2-day formal ECHO courses and also the World Interactive Network Focused On Critical UltraSound course. Furthermore, the first author performed ongoing mentored studies along with a pediatric echocardiographer over the last decade. However, such extensive training may not be necessary, and there are several reports of training periods ranging between 3 and 12 hours that may be sufficient for noncardiologist desirous of gaining proficiency in focused ECHO in the emergency department (ED) or ICU (3, 4). The third query relates to assessment of circulating volume status by studying the respiratory variation of the inferior vena cava (IVC) in spontaneously breathing versus ventilated critically ill patients. This is an important issue. Assessment of fluid responsiveness remains a daily challenge in patients with shock and hypoperfusion, and despite the enormous advances in the medical field, we do not yet have a perfect test to assess volume status and volume responsiveness. IVC size and respiratory variation have been shown to correlate well with central venous pressure (despite its limitations) or volume responsiveness (the more relevant clinical variable) in a variety of patient environments (5). With respect to studies of IVC variability in spontaneously breathing patients versus patients on controlled ventilation, we agree that most of the validations in the ICU have been performed on ventilated patients (6), whereas ED-based literature is based predominantly on spontaneously breathing patients (7, 8). Furthermore, most reports are based on the adult experience with little in children. Regardless, the finding of a collapsing IVC in the absence of intra-abdominal hypertension in a patient with shock almost certainly indicates hypovolemia whether they are spontaneously breathing or mechanically ventilated (9). However, we agree with Gaspar et al (1) that it may be premature to draw any firm conclusions about the value of IVC diameter as a sole and unambiguous indicator of volume status in children with shock. Indeed, this is the rationale for our study: rather than rely on any one monitoring modality to determine need for volume augmentation or vasoactive therapy, we elected to integrate diagnostic information from a variety of tests using multimodal monitoring to assess the hemodynamic variables of our patients. Finally, Gaspar et al (1) conclude by proposing that we perform a prospective study comparing pediatric septic shock management and outcome with the standard surviving sepsis campaign protocol versus treatment guided by usual hemodynamic www.pccmjournal.org

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