Volume and Pressure Delivery During Pediatric High-Frequency Oscillatory Ventilation. (Stulce)

Wong R, Deakers T, Hotz J, et al. Volume and Pressure Delivery During Pediatric High-Frequency Oscillatory Ventilation. Pediatr Crit Care Med. 2017 Apr;18(4):e189-e194.

OBJECTIVE: Identify variables independently associated with delivered tidal volume (VT) and measured mean airway pressure during high-frequency oscillatory ventilation across the range of pediatric endotracheal tube sizes.

DESIGN: In vitro study.

SETTING: Research laboratory.

INTERVENTIONS: An in vitro bench model of the intubated pediatric respiratory system during high-frequency oscillatory ventilation was used to obtain delivered VT and mean airway pressure (in the distal lung) for various endotracheal tube sizes. Measurements were taken at different combinations of ventilator set mean airway pressure (Paw), amplitude (ΔP), frequency, and test lung compliance. Multiple regression analysis was used to construct multivariable models predicting delivered VT and mean airway pressure.

MEASUREMENTS AND MAIN RESULTS: Variables independently associated with higher delivered VT for all endotracheal tube sizes include higher ΔP (p < 0.001), lower frequency (p < 0.001), and higher test lung compliance (p < 0.001). A multiplicative interaction between frequency and ΔP magnifies the delivered VT when ΔP is high and frequency is low (p < 0.001). Delivered mean airway pressure becomes lower than set Paw as ΔP increases (p < 0.001) and frequency increases (p < 0.05). Ventilator set Paw is the largest determinant of delivered mean airway pressure; however, increasing ΔP resulted in a lower delivered mean airway pressure. For example, in a 4.0 mm ID endotracheal tube, increasing ΔP by 10 cm H2O resulted in an average decrease of delivered mean airway pressure by 4.5%.

CONCLUSIONS: This is the first study to quantify the interaction between ΔP and frequency in delivered VT and the effect of ΔP and frequency on delivered mean airway pressure. These results demonstrate the need to measure or estimate VT and delivered pressures during high-frequency oscillatory ventilation and may be useful in determining optimal strategies for lung protective ventilation during high-frequency oscillatory ventilation.

Pediatric Acute Respiratory Distress Syndrome in Pediatric Allogeneic Hematopoietic Stem Cell Transplants: A Multicenter Study. (Stulce)

Rowan CM, Smith LS, Loomis A, et al. Pediatric Acute Respiratory Distress Syndrome in Pediatric Allogeneic Hematopoietic Stem Cell Transplants: A Multicenter Study. Pediatr Crit Care Med. 2017 Apr;18(4):304-309.

OBJECTIVE: Immunodeficiency is both a preexisting condition and a risk factor for mortality in pediatric acute respiratory distress syndrome. We describe a series of pediatric allogeneic hematopoietic stem cell transplant patients with pediatric acute respiratory distress syndrome based on the recent Pediatric Acute Lung Injury Consensus Conference guidelines with the objective to better define survival of this population.

DESIGN: Secondary analysis of a retrospective database.

SETTING: Twelve U.S. pediatric centers.

PATIENTS: Pediatric allogeneic hematopoietic stem cell transplant recipients requiring mechanical ventilation.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: During the first week of mechanical ventilation, patients were categorized as: no pediatric acute respiratory distress syndrome or mild, moderate, or severe pediatric acute respiratory distress syndrome based on oxygenation index or oxygen saturation index. Univariable logistic regression evaluated the association between pediatric acute respiratory distress syndrome and PICU mortality. A total of 91.5% of the 211 patients met criteria for pediatric acute respiratory distress syndrome using the Pediatric Acute Lung Injury Consensus Conference definition: 61.1% were severe, 27.5% moderate, and 11.4% mild. Overall survival was 39.3%. Survival decreased with worsening pediatric acute respiratory distress syndrome: no pediatric acute respiratory distress syndrome 66.7%, mild 63.6%, odds ratio = 1.1 (95% CI, 0.3-4.2; p = 0.84), moderate 52.8%, odds ratio = 1.8 (95% CI, 0.6-5.5; p = 0.31), and severe 24.6%, odds ratio = 6.1 (95% CI, 2.1-17.8; p < 0.001). Nonsurvivors were more likely to have multiple consecutive days at moderate and severe pediatric acute respiratory distress syndrome (p < 0.001). Moderate and severe patients had longer PICU length of stay (p = 0.01) and longer mechanical ventilation course (p = 0.02) when compared with those with mild or no pediatric acute respiratory distress syndrome. Nonsurvivors had a higher median maximum oxygenation index than survivors at 28.6 (interquartile range, 15.5-49.9) versus 15.0 (interquartile range, 8.4-29.6) (p < 0.0001).

CONCLUSION: In this multicenter cohort, the majority of pediatric allogeneic hematopoietic stem cell transplant patients with respiratory failure met oxygenation criteria for pediatric acute respiratory distress syndrome based on the Pediatric Acute Lung Injury Consensus Conference definition within the first week of invasive mechanical ventilation. Length of invasive mechanical ventilation, length of PICU stay, and mortality increased as the severity of pediatric acute respiratory distress syndrome worsened.

Suspected Cerebral Edema in Diabetic Ketoacidosis: Is There Still a Role for Head CT in Treatment Decisions? (Colman)

Soto-Rivera CL, Asaro LA, Agus MS, DeCourcey DD. Suspected Cerebral Edema in Diabetic Ketoacidosis: Is There Still a Role for Head CT in Treatment Decisions?  Pediatr Crit Care Med. 2017 Jan 19. [Epub ahead of print]

OBJECTIVES: Neurologic deterioration associated with cerebral edema in diabetic ketoacidosis is typically sudden in onset, progresses rapidly, and requires emergent treatment. The utility of brain imaging by head CT in decisions to treat for cerebral edema has not been previously studied. The objective of this study was to describe the characteristics of pediatric patients with diabetic ketoacidosis who develop altered mental status and evaluate the role of head CT in this cohort.

DESIGN: Retrospective analysis of clinical, biochemical, and radiologic data.

SETTING: Tertiary care children’s hospital (2004-2010).

PATIENTS: Six hundred eighty-six admissions of patients (< 26 yr) with diabetic ketoacidosis.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Altered mental status was documented during 96 of 686 diabetic ketoacidosis admissions (14%). Compared with alert patients, those with altered mental status were younger (median, 12.0 vs 13.1 yr; p = 0.007) and more acidotic (pH, 7.04 vs 7.19; p < 0.001), with higher serum osmolality (328 vs 315 mOsm/kg; p < 0.001) and longer hospital length of stay (4.5 vs 3 d; p = 0.002). Head CT was performed during 60 of 96 diabetic ketoacidosis admissions with altered mental status (63%), 16 (27%) of which had abnormal results. Hyperosmolar therapy for cerebral edema was given during 23 of the 60 admissions (38%), during which 12 (52%) had normal head CT results, eight of these 12 (67%) after cerebral edema treatment and four (33%) before. Of the 11 admissions with abnormal head CT results that received hyperosmolar therapy, four head CT scan (36%) occurred after hyperosmolar treatment and seven (64%) before. For the 11 admissions with head CT before cerebral edema treatment, there was a median 2-hour delay between head CT and hyperosmolar therapy.

CONCLUSIONS: In this single-center retrospective study, there was no evidence that decisions about treatment of patients with diabetic ketoacidosis and suspected cerebral edema were enhanced by head CT, and head CT may have led to a significant delay in hyperosmolar therapy.

Long-Term Survival and Causes of Late Death in Children Treated With Extracorporeal Membrane Oxygenation. (Colman)

von Bahr V, Hultman J, Eksborg S, et al. Long-Term Survival and Causes of Late Death in Children Treated With Extracorporeal Membrane Oxygenation. Pediatr Crit Care Med. 2017 Jan 10.

OBJECTIVE: Extracorporeal membrane oxygenation has been used in patients with severe circulatory or respiratory failure since the 1970s, but the knowledge on long-term survival in this group is scarce. The aim of the present study was to investigate the 10-year survival rates and causes of late death in children treated with extracorporeal membrane oxygenation.

DESIGN: Single-center, retrospective cohort study.

SETTING: Tertiary referral center for extracorporeal life support.

PATIENTS: Neonatal and pediatric patients treated with extracorporeal membrane oxygenation from 1987 to December 2013.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Survival status was obtained from the national Causes of Death registry. Patient background data along with data on survival and causes of death were collected. Survival rates were calculated using the Kaplan-Meier method. Of 400 subjects, 76% survived to discharge. The median follow-up time in survivors was 7.2 years. There was a high mortality rate within the first months after discharge. In the group of patients who survived the first 90 days after treatment, the 10-year survival rates were 93% in neonates and 89% in pediatric patients and were particularly beneficial in patients whose indication for extracorporeal membrane oxygenation was meconium aspiration syndrome, trauma, or infectious diseases. Late deaths were seen in some diagnostic groups, but the Kaplan-Meier curves plateaued over time.

CONCLUSIONS: Children who survive the first months after treatment with extracorporeal membrane oxygenation have a high long-term survival rate. The prognosis is especially favorable in patients with reversible conditions.

Amiodarone Versus Lidocaine for Pediatric Cardiac Arrest Due to Ventricular Arrhythmias: A Systematic Review. (Colman)

McBride ME, Marino BS, Webster G, et al. Amiodarone Versus Lidocaine for Pediatric Cardiac Arrest Due to Ventricular Arrhythmias: A Systematic Review. Pediatr Crit Care Med. 2016 Dec 23.

OBJECTIVE: We performed a systematic review as part of the International Liaison Committee on Resuscitation process to create a consensus on science statement regarding amiodarone or lidocaine during pediatric cardiac arrest for the 2015 International Liaison Committee on Resuscitation’s Consensus on Science and Treatment Recommendations.

DATA SOURCES: Studies were identified from comprehensive searches in PubMed, Embase, and the Cochrane Library.

STUDY SELECTION: Studies eligible for inclusion were randomized controlled and observational studies on the relative clinical effect of amiodarone or lidocaine in cardiac arrest.

DATA EXTRACTION: Studies addressing the clinical effect of amiodarone versus lidocaine were extracted and reviewed for inclusion and exclusion criteria by the reviewers. Studies were rigorously analyzed thereafter.

DATA SYNTHESIS: We identified three articles addressing lidocaine versus amiodarone in cardiac arrest: 1) a prospective study assessing lidocaine versus amiodarone for refractory ventricular fibrillation in out-of-hospital adults; 2) an observational retrospective cohort study of inpatient pediatric patients with ventricular fibrillation or pulseless ventricular tachycardia who received lidocaine, amiodarone, neither or both; and 3) a prospective study of ventricular tachycardia with a pulse in adults. The first study showed a statistically significant improvement in survival to hospital admission with amiodarone (22.8% vs 12.0%; p = 0.009) and a lack of statistical difference for survival at discharge (p = 0.34). The second article demonstrated 44% return of spontaneous circulation for amiodarone and 64% for lidocaine (odds ratio, 2.02; 1.36-3.03) with no statistical difference for survival at hospital discharge. The third article demonstrated 48.3% arrhythmia termination for amiodarone versus 10.3% for lidocaine (p < 0.05). All were classified as lower quality studies without preference for one agent.

CONCLUSIONS: The confidence in effect estimates is so low that International Liaison Committee on Resuscitation felt that a recommendation to use of amiodarone over lidocaine is too speculative; we suggest that amiodarone or lidocaine can be used in the setting of pulseless ventricular tachycardia/ventricular fibrillation in infants and children.

A Systemic Inflammation Mortality Risk Assessment Contingency Table for Severe Sepsis. (Colman)

Carcillo JA, Sward K, Halstead ES, et al. A Systemic Inflammation Mortality Risk Assessment Contingency Table for Severe Sepsis. Pediatr Crit Care Med. 2016 Dec 9. [Epub ahead of print]

OBJECTIVES: We tested the hypothesis that a C-reactive protein and ferritin-based systemic inflammation contingency table can track mortality risk in pediatric severe sepsis.

DESIGN: Prospective cohort study.

SETTING: Tertiary PICU.

PATIENTS: Children with 100 separate admission episodes of severe sepsis were enrolled.

INTERVENTIONS: Blood samples were attained on day 2 of sepsis and bi-weekly for biomarker batch analysis. A 2 × 2 contingency table using C-reactive protein and ferritin thresholds was developed.

MEASUREMENTS AND MAIN RESULTS: A C-reactive protein of 4.08 mg/dL and a ferritin of 1,980 ng/mL were found to be optimal cutoffs for outcome prediction at first sampling (n = 100) using the Youden index. PICU mortality was increased in the “high-risk” C-reactive protein greater than or equal to 4.08 mg/dL and ferritin greater than or equal to 1,980 ng/mL category (6/13 [46.15%]) compared with the “intermediate-risk” C-reactive protein greater than or equal to 4.08 mg/dL and ferritin less than 1,980 ng/mL or C-reactive protein less than 4.08 mg/dL and ferritin greater than or equal to 1,980 ng/mL categories (2/43 [4.65%]), and the “low-risk” C-reactive protein less than 4.08 mg/dL and ferritin less than 1,980 ng/mL category (0/44 [0%]) (odds ratio, 36.43 [95% CI, 6.16-215.21]). The high-risk category was also associated with the development of immunoparalysis (odds ratio, 4.47 [95% CI, 1.34-14.96]) and macrophage activation syndrome (odds ratio, 24.20 [95% CI, 5.50-106.54]). Sixty-three children underwent sequential blood sampling; those who were initially in the low-risk category (n = 24) and those who subsequently migrated (n = 19) to the low-risk category all survived, whereas those who remained in the “at-risk” categories had increased mortality (7/20 [35%]; p < 0.05).

CONCLUSIONS: A C-reactive protein- and ferritin-based contingency table effectively assessed mortality risk. Reduction in systemic inflammation below a combined threshold C-reactive protein of 4.08 mg/dL and ferritin of 1,980 ng/mL appeared to be a desired response in children with severe sepsis.