Adalberto Torres

Severity assessment in children hospitalized with bronchiolitis using the pediatric component of the Comprehensive Severity Index.

Objective Practice variation in the management of children hospitalized with bronchiolitis may result in significant differences in resource utilization. Determination of cost-effective care requires an objective means of adjusting for severity. We examined the correlation of the pediatric component of the Comprehensive Severity Index (CSI) with resource utilization in children hospitalized with bronchiolitis at ten children’s medical centers. Design Demographics, clinical findings, laboratory results, interventions, and outcomes were retrospectively extracted from the charts of 804 consecutive children with International Classification of Disease, Ninth Revision codes for bronchiolitis from 10 children’s medical centers. Comorbidities of prematurity, heart disease, and a prior history of wheezing or hospitalization, and the viral etiology of the illness were specifically examined. CSI scoring was performed at admission and maximum and correlated with patient variables and measures of resource utilization (hospital costs, length of stay, pediatric intensive care unit admission, and intubation). The performance of CSI relative to the Pediatric Risk of Mortality III was also evaluated. Setting Ten tertiary children’s medical centers. Interventions None. Measurements and Main Results One child died and >99% of children returned to their baseline state of health. Admission CSI was comparable to the aggregate of all patient variables in its correlation with hospital costs (r2 = 0.23 vs. r2 = 0.24, respectively) and lengths of stay (r2 = 0.23 vs. r2 = 0.24, respectively). Maximum CSI had the highest correlation coefficient with hospital costs (r2 = 0.42) and lengths of stay (r2 = 0.41), whereas the correlation of admission Pediatric Risk of Mortality III scores with costs was r2 = 0.12 and with lengths of stay was r2 = 0.07. CSI scores also correlated well with measures of resource utilization in subgroups of bronchiolitis patients with comorbidities or other risk factors for severe disease. Conclusions CSI scores correlate well with resource use in pediatric patients hospitalized with bronchiolitis. This severity scoring system may be useful in assessing the cost-effectiveness of their care.

Ionized magnesium concentrations in critically ill children.

OBJECTIVE To test the hypothesis that many critically ill children exhibit ionized hypomagnesemia despite having normal total magnesium (TMg) concentrations. DESIGN A prospective, observational study with convenience sampling. SETTING Pediatric and cardiovascular intensive care units of a large childrens hospital. PATIENTS Patients aged 1 day to 21 yrs admitted from January 1 to October 31, 1996. Patients with chronic renal failure or weight <3 kg were excluded. A group of healthy children involved in a school-based nutritional assessment study were also studied. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Sixty-seven patients (5.4+/-5.7 [SD] yrs) and 24 healthy children (10.84+/-0.93 yrs, p< .001) were studied. Plasma was assayed for ionized magnesium (IMg) using a blood analyzer. Forty (59%)/67 critically ill subjects had IMg concentrations <0.40 mmol/L, the lowest published normal value and the lowest value observed in our group of healthy children. Of these, 24 (60%)/40 had normal TMg concentrations. IMg was significantly (p=.00) lower in critically ill subjects than in the group of healthy children (0.37+/-0.10 mmol/L vs. 0.46+/-0.03 mmol/L). IMg did not correlate strongly with ionized calcium (r2=0.49), albumin (r2=0.09), or pH (r2=0.18). CONCLUSION Many critically ill children exhibit ionized hypomagnesemia with normal TMg concentrations. These children would not be recognized as magnesium-deficient based on routine TMg testing. Critically ill children exhibited significantly lower concentrations of IMg than a group of healthy children.

Effect of nitric oxide, perfluorocarbon, and heliox on minute volume measurement and ventilator volumes delivered.

OBJECTIVE To determine the effect of heliox, nitric oxide (NO), and perfluorocarbon on differential pressure pneumotachometer characteristics and to determine the effect of heliox on volumes delivered by the Siemens S900C (S900C), and Servo Ventilator 300 (SV300) ventilators. DESIGN Prospective, laboratory study. SETTING Pulmonary laboratory of a tertiary care, nonprofit childrens hospital. APPARATUS SV300, S900C ventilator, differential pressure pneumotachometer. INTERVENTIONS Dual pneumotachometers were connected in series to a 0.5-L calibration syringe and a 1-L anesthesia bag creating a closed system. Calibration of the pneumotachometers was done in room air at ambient temperature with 100 strokes. Accepted accuracy of measured volumes is within 0.5%. Flow-conductance curves were constructed using 100 strokes each for heliox (70:30 mixture), NO, and perfluorocarbon. Expired gases of room air and a 70:30 mixture of heliox from the above ventilators were collected into a nondiffusing gas collection bag, and the volume was measured in a chain-compensated gasometer. Ten sets of 500-mL breaths (20 breaths each set) and 100-mL breaths (40 breaths each set) were collected. The paired Students t-test was used to detect significant differences in measured volumes, with significance defined as p < .01. MEASUREMENTS AND MAIN RESULTS Volumes measured with the pneumotachometer using 25 ppm of NO, 50 ppm of NO, and perfluorocarbon were within +0.25%, -0.7%, and +0.4%, respectively (p = .155, p = .001, p = .06). Heliox decreased the conductance of the pneumotachometer, thereby increasing the measured volume by 15% (p < .001). However, heliox did not affect its linearity. Heliox had no affect on volumes delivered by the S900C. However, the SV300 delivered 7.9% less volume of heliox at a set tidal volume of 500 mL and 10.8% less at a set tidal volume of 100 mL. CONCLUSIONS A 70:30 mixture of heliox caused a significantly overestimated gas volume measured and, therefore, an underestimated gas volume delivered by SV300. NO at 25 ppm and perfluorocarbon did not interfere with the accuracy of a differential pressure pneumotachometer. However, at 50 ppm, NO caused a difference in measured gas volume that was statistically, but not clinically, significant. Application of pneumotachometers in critically ill children receiving heliox requires recalibration. Heliox did not affect volumes delivered with the S900C ventilator. Although volumes delivered with the SV300 were significantly reduced by heliox, the difference can be corrected easily by increasing minute ventilation until expired tidal volume equals desired tidal volume.

Comparison of total resistive work of breathing in two generations of ventilators in an animal model

Spontaneous breathing through an endotracheal tube and ventilator circuit is associated with an increased work of breathing (WOB). Recently, pediatric ventilators have introduced improved features to optimize patient‐ventilator interactions. We performed an experiment utilizing an animal model to compare total resistive WOB of two widely used ventilators, the Siemens Servo Ventilator 300 (SV300) with patient‐optimized features, such as flow‐triggering and rapid response time, and the Siemens 900C (S900C) without those features. A total of 120 experiments of 10 minutes duration each were performed in 6 anesthetized, intubated lambs. In each experiment, the animal was randomized to either pressure support ventilation (PSV) of 5 cm H2O, or continuous positive airway pressure (CPAP) with 0 cmH2O end expiratory pressure (ZEEP) while supported by the SV300 or the S900C. Each animal was used as its own control. WOB was measured with a Bicore monitoring device as WOB of the animal (WOBp), WOB of the ventilator (WOBv), and the pressure time product (PTP) for each breath during the experiment. Oxygen consumption (VO2) of the animal was measured using breath‐by‐breath gas analysis with a customized metabolic monitoring system. A Wilcoxon signed rank sum test was used for analysis. All comparisons between the ventilators for both CPAP and PSV showed a statistically significant difference (p < 0.001). WOBp was reduced by 47% during pressure support ventilation (PSV) and by 47% during CPAP when the SV300 was used compared to the S900C. We conclude that WOB is significantly lower in animals ventilated with the SV300 than with the S900C ventilator, and we speculate that ventilators with the features of the SV300 may offer advantages in ventilating pediatric patients. Pediatr Pulmonol. 1996; 22:58–66.

Simultaneous Acquired Self-limited Hemophagocytic Lymphohistiocytosis and Kikuchi Necrotizing Lymphadenitis in a 16-Year-Old Teenage Girl: A Case Report and Review of the Literature.

Objectives The aim of this study was to increase education and awareness among pediatric practitioners of possibility of simultaneous hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease/Kikuchi disease occurring in the pediatric population and the diagnostic dilemma it can present. We describe a case presentation of acquired and self-limited simultaneous hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease in a 16-year-old in the United States who presented with fevers, night sweats, and joint pain, along with tiredness and decreased appetite along with pancytopenia and elevated lactate dehydrogenase. To the best of our knowledge, simultaneous hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto in the pediatric population has not been described in North America but remains fairly common in Asia. The literature on both diseases and their simultaneous occurrence is comprehensively reviewed. Methods This was a case report and review of the literature. Results The patient was diagnosed with both hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease based on bone marrow aspiration/biopsy and axillary node biopsy, respectively. Both illnesses resolved completely. Conclusions Benign causes of pancytopenia and elevated lactate dehydrogenase exist, but they may not be always straightforward diagnostically. Bone marrow aspiration and lymph node biopsy may be helpful in ascertaining the diagnosis. Hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease may represent a continuum of illness.

Measuring lung volume during high-frequency oscillatory ventilation in neonates-ready for prime time?*.

Critical Care Medicine www.ccmjournal.org 2649 2. Koch CG, Li L, Sessler DI, et al: Duration of red-cell storage and complications after cardiac surgery. N Engl J Med 2008; 358:1229–1239 3. Baron DM, Beloiartsev A, Nakagawa A, et al: Adverse Effects of Hemorrhagic Shock Resuscitation With Stored Blood Are Ameliorated by Inhaled Nitric Oxide in Lambs. Crit Care Med 2013; 41:2492–2501 4. Bennett-Guerrero E, Veldman TH, Doctor A, et al: Evolution of adverse changes in stored RBCs. Proc Natl Acad Sci U S A 2007; 104:17063–17068 5. Weiskopf RB, Feiner J, Toy P, et al: Fresh and stored red blood cell transfusion equivalently induce subclinical pulmonary gas exchange deficit in normal humans. Anesth Analg 2012; 114:511–519 6. Fergusson DA, Hébert P, Hogan DL, et al: Effect of fresh red blood cell transfusions on clinical outcomes in premature, very low-birth-weight infants: The ARIPI randomized trial. JAMA 2012; 308:1443–1451 7. Ricciardolo FL, Sterk PJ, Gaston B, et al: Nitric oxide in health and disease of the respiratory system. Physiol Rev 2004; 84:731–765 8. Harr JN, Moore EE, Johnson J, et al: Antiplatelet therapy is associated with decreased transfusion-associated risk of lung dysfunction, multiple organ failure, and mortality in trauma patients. Crit Care Med 2013; 41:399–404