Sarah Rubin

Infant botulism: a 30-year experience spanning the introduction of botulism immune globulin intravenous in the intensive care unit at Childrens Hospital Los Angeles.

OBJECTIVE. To report a tertiary care hospitals 30-year experience with the diagnosis, treatment, and outcome of infant botulism in the PICU before and after the availability of Botulism Immune Globulin Intravenous. METHODS. This was a retrospective medical chart review of the 67 patients who had received a diagnosis of infant botulism and were admitted to the ICU from 1976 to 2005. The ages on presentation, length of hospital stay, length of ICU stay, length of mechanical ventilation, and type of botulism toxin were recorded and compared for patients who had received Botulism Immune Globulin Intravenous and those who had not. On the basis of our results, conclusions were drawn regarding the effect of Botulism Immune Globulin Intravenous on the morbidity of infant botulism. RESULTS. Sixty-seven patients’ charts were reviewed; 23 male and 29 female patients did not receive Botulism Immune Globulin Intravenous. Of patients who did not receive Botulism Immune Globulin Intravenous, the median age at presentation was 71 days, median length of hospital stay was 35 days, ICU stay was 24 days, and duration of mechanical ventilation was 17 days. A total of 40% had type A toxin, and 60% had type B toxin. There was a significant difference between patients with toxin types A and B in length of hospital stay but not length of ICU stay or mechanical ventilation. Patients with type A toxin were significantly older than patients with type B toxin. Fifteen children received Botulism Immune Globulin Intravenous. There were statistically significant differences in length of hospital stay, length of ICU stay, and length of mechanical ventilation between patients who received Botulism Immune Globulin Intravenous and those who did not. CONCLUSIONS. The use of Botulism Immune Globulin Intravenous significantly decreased the length of ICU stay, length of mechanical ventilation, and overall hospital stay in children with infant botulism.

Effort of breathing in children receiving high-flow nasal cannula.

Objective: High-flow humidified nasal cannula is often used to provide noninvasive respiratory support in children. The effect of high-flow humidified nasal cannula on effort of breathing in children has not been objectively studied, and the mechanism by which respiratory support is provided remains unclear. This study uses an objective measure of effort of breathing (Pressure. Rate Product) to evaluate high-flow humidified nasal cannula in critically ill children. Design: Prospective cohort study. Setting: Quaternary care free-standing academic children’s hospital. Patients: ICU patients younger than 18 years receiving high-flow humidified nasal cannula or whom the medical team planned to extubate to high-flow humidified nasal cannula within 72 hours of enrollment. Interventions: An esophageal pressure monitoring catheter was placed to measure pleural pressures via a Bicore CP-100 pulmonary mechanics monitor. Change in pleural pressure (&Dgr;Pes) and respiratory rate were measured on high-flow humidified nasal cannula at 2, 5, and 8 L/min. &Dgr;Pes and respiratory rate were multiplied to generate the Pressure.Rate Product, a well-established objective measure of effort of breathing. Baseline Pes, defined as pleural pressure at end exhalation during tidal breathing, reflected the positive pressure generated on each level of respiratory support. Measurements and Main Results: Twenty-five patients had measurements on high-flow humidified nasal cannula. Median age was 6.5 months (interquartile range, 1.3–15.5 mo). Median Pressure,Rate Product was lower on high-flow humidified nasal cannula 8 L/min (median, 329 cm H2O·min; interquartile range, 195–402) compared with high-flow humidified nasal cannula 5 L/min (median, 341; interquartile range, 232–475; p = 0.007) or high-flow humidified nasal cannula 2 L/min (median, 421; interquartile range, 233–621; p < 0.0001) and was lower on high-flow humidified nasal cannula 5 L/min compared with high-flow humidified nasal cannula 2 L/min (p = 0.01). Baseline Pes was higher on high-flow humidified nasal cannula 8 L/min than on high-flow humidified nasal cannula 2 L/min (p = 0.03). Conclusions: Increasing flow rates of high-flow humidified nasal cannula decreased effort of breathing in children, with the most significant impact seen from high-flow humidified nasal cannula 2 to 8 L/min. There are likely multiple mechanisms for this clinical effect, including generation of positive pressure and washout of airway dead space.

Pediatric Early Warning Score and unplanned readmission to the pediatric intensive care unit.

BACKGROUND AND OBJECTIVES Early unplanned Pediatric Intensive Care Unit (PICU) readmission is associated with greater length of stay and mortality. No tools exist to identify children at risk for PICU readmission. The Pediatric Early Warning Score (PEWS) currently identify children at risk for deterioration on the ward. Our primary objective was to evaluate the ability of PEWS to identify children at risk for unplanned PICU readmission. METHODS A single-center case-control study of 189 children (38 cases and 151 age-matched controls) 18years or younger transferred from the PICU to the pediatric ward from January 1, 2010-March 30, 2013, at an urban tertiary care childrens hospital was conducted. RESULTS Thirty-eight cases had unplanned PICU readmission within 48hours of transfer to pediatric ward, whereas 151 controls were not readmitted. The PEWS assigned prior to PICU discharge and first PEWS assigned on the ward were collected for cases and controls. Each 1-point increase in the PEWS score significantly increased risk of PICU readmission (odds ratios [95% confidence intervals], 1.6 [1.12-2.27; P = .009] and 1.89 [1.33-2.69; P < .001], respectively). Discrimination ability of PEWS for PICU readmission improved when chronic diagnoses were included. CONCLUSIONS Higher PEWS scores were associated with increased risk of unplanned PICU readmission. However, cutoff scores are not sensitive or specific enough to be clinically useful. Adding chronic disease variables may improve the clinical utility of cutoff PEWS scores.

Monitoring Dead Space in Mechanically Ventilated Children: Volumetric Capnography Versus Time-Based Capnography

BACKGROUND: Volumetric capnography dead-space measurements (physiologic dead-space-to-tidal-volume ratio [VD/VT] and alveolar VD/VT) are considered more accurate than the more readily available time-based capnography dead-space measurement (end-tidal alveolar dead-space fraction [AVDSF]). We sought to investigate the correlation between volumetric capnography and time-based capnography dead-space measurements. METHODS: This was a single-center prospective cohort study of 65 mechanically ventilated children with arterial lines. Physiologic VD/VT, alveolar VD/VT, and AVDSF were calculated with each arterial blood gas using capnography data. RESULTS: We analyzed 534 arterial blood gases from 65 children (median age 4.9 y, interquartile range 1.7–12.8). The correlation between physiologic VD/VT and AVDSF (r = 0.66, 95% CI 0.59–0.72) was weaker than the correlation between alveolar VD/VT and AVDSF (r = 0.8, 95% CI 0.76–0.85). The correlation between physiologic VD/VT and AVDSF was weaker in children with low PaO2/FIO2 (< 200 mm Hg), low exhaled VT (< 100 mL), a pulmonary reason for mechanical ventilation, or large airway VD (> 3 mL/kg). All 3 dead-space measurements were highly correlated (r > 0.7) in children without hypoxemia (PaO2/FIO2 > 300 mm Hg), mechanically ventilated for a neurologic or cardiac reason, or on significant inotropes or vasopressors. CONCLUSIONS: In mechanically ventilated children without significant hypoxemia or with cardiac output-related dead-space changes, physiologic VD/VT was highly correlated with AVDSF and alveolar VD/VT. In children with significant hypoxemia, physiologic VD/VT was poorly correlated with AVDSF. Alveolar VD/VT and AVDSF correlated well in most tested circumstances. Therefore, AVDSF may be useful in most children for alveolar dead-space monitoring.

Pediatric rheumatic disease in the intensive care unit: lessons learned from 15 years of experience in a tertiary care pediatric hospital.

Objective: This study describes the 15-yr experience of a large urban tertiary care children’s hospital in treating critically ill patients with pediatric rheumatic diseases. Design: Retrospective case series. Setting: Children’s Hospital Los Angeles, a large urban tertiary care children’s hospital. Patients: All patients with pediatric rheumatic diseases admitted to the Children’s Hospital Los Angeles pediatric intensive care unit from January 1995 to July 2009. Interventions: None. Measurements and Main Results: An internal database and medical records were reviewed for demographics, diagnoses, treatments, organ dysfunction, interventions, infections, and outcomes. Standardized mortality ratio was calculated based on Pediatric Risk of Mortality III estimated mortality. Factors associated with mortality were identified by univariate analyses. Ninety patients with 122 total admissions were identified. The majority of patients were Hispanic (63%), female (73%), and had systemic lupus erythematosus (62%). Pediatric rheumatic disease-related complications (50%) were the most common reason for admission; 32% of admissions involved multiorgan dysfunction. Eighteen admissions (15%) resulted in mortality. Deaths were most commonly attributed to combined infection and active rheumatic disease (50%), infection only (22%), rheumatic disease only (11%), or other causes (17%). In 30 (25%) admissions, a new rheumatologic diagnosis was established. Standardized mortality ratio was 0.72 (95% confidence interval 0.38-1.25) for pediatric rheumatic disease patients compared to 0.87 (95% confidence interval 0.79-0.96) for all pediatric intensive care unit patients. Factors associated with mortality included use of mechanical ventilation, vasopressors, and renal replacement (continuous venovenous hemodialysis) (all p < .05). Conclusions: Pediatric rheumatic disease-related complications were the principal cause of pediatric intensive care unit admission. Deaths occurred most often from severe infections in patients with active rheumatic disease. Pediatric rheumatology patients admitted to the pediatric intensive care unit had outcomes similar to the global pediatric intensive care unit population when adjusted for severity of illness.

An informatics architecture for the Virtual Pediatric Intensive Care Unit

The Laura P. and Leland K. Whittier Virtual Pediatric Intensive Care Unit (VPICU) is an ambitious research network focused on building online databases for improving decision-making in pediatric intensive care units. Increasingly, there is a need to unify previously distributed and heterogeneous information captured in these databases to support both traditional retrospective support ad-hoc studies, and ad-hoc analyses. VPICU and NASAs Jet Propulsion Laboratory have constructed a reference architecture and implementation framework that addresses these needs. The architecture is unobtrusive, scalable, and secure, with a strong focus on rapid deployment and integration. This paper reports on the current status of our efforts and details the strength of the framework via our recent work in unsupervised discovery of patient similarity within the hospital.

Case study: Semantic annotation of a pediatric critical care research study

KEY POINTS: Interoperability remainsan important national informatics focus Nuances ofmeaning can be lost during terminology efforts It is important for nurses with clinical expertise to be aware of and engage in interoperability related initiatives C linical care, research, and quality initiatives such as the Learning Health System require organizations to share and understand each others data. Such interoperability requires standard messaging formats and standard terminologies. The Office of the National Coordinator for Health IT seeks to achieve electronic health record (EHR) connectivity before 2018, but some believe that, despite limited successes, it will take at least another decade before interoperability is realized on a national scale. Establishing common understanding across all stakeholders is complicated, in part because the meaning (semantics) and format of terms are often context dependent. Thus, it remains important to assess the extent to which standard terminologies appropriately represent clinical meaning in specific contexts. This article reports a case study in which a pediatric critical care research network registry was mapped to standard terminologies. The University of Utah Institutional Review Board approved this study; this evaluation did not involve human subjects or patient data.

Elevated Positive End-Expiratory Pressure Decreases Cardiac Index in a Rhesus Monkey Model

Rationale: Clinicians are often concerned that higher positive end-expiratory pressure (PEEP) will decrease cardiac index (CI). PEEP affects CI through multiple inter-related mechanisms. The adult Rhesus monkey is an excellent model to study cardiopulmonary interaction due to similar pulmonary and chest wall compliances to human infants. Objective: Our goal was to examine the impact of increasing PEEP on CI in Rhesus monkeys as a model for critically ill children. Methods: Prospective, experimental animal study. Nine healthy anesthetized, intubated Rhesus monkeys were allowed to breathe spontaneously at a PEEP of 0, 5, 10, and 15 cm H2O while CI was measured with an ultrasonic Doppler (USCOM). Measurements and main results: Cardiac index decreased between PEEP levels of 5 and 15 cm H2O. The mean decrease in CI for the entire cohort of monkeys was 18% (p < 0.01) with a range of −11 to 49%. Stroke volume and oxygen delivery also decreased between PEEP levels of 5 and 15 cm H2O (p < 0.01). Conclusion: Between PEEP levels of 5 and 15 cm H2O, there was a decrease in CI, stroke volume, and oxygen delivery in intubated Rhesus monkeys. A plausible mechanism is that over-distention of normally compliant lungs at increased PEEP resulted in decreased preload to the right ventricle, outweighing the potentially beneficial decrease in left ventricular afterload or pulmonary vascular resistance. Further investigation is warranted, particularly in children with lung injury, who have historically benefited from increased PEEP levels without over-distention.