Evaluation of a Pediatric Early Warning Score Across Different Subspecialty Patients. (Duke)

Dean NP, et al. Evaluation of a Pediatric Early Warning Score Across Different Subspecialty Patients. Pediatr Crit Care Med. 2017 Jul;18(7):655-660.

OBJECTIVE: To evaluate the ability of a Pediatric Early Warning Score to predict deterioration in different subspecialty patient populations.

DESIGN: Single center, retrospective cohort study. Patients were classified into five groups: 1) cardiac; 2) hematology/oncology/bone marrow transplant; 3) surgical; 4) neurologic; and 5) general medical. The relationship between the Pediatric Early Warning Score and unplanned ICU transfer requiring initiation of specific ICU therapies (intubation, high-flow nasal cannula, noninvasive ventilation, inotropes, or aggressive fluid hydration within 12 hr of transfer) was evaluated.

SETTING: Tertiary care, free-standing, academic children’s hospital.

PATIENTS: All hospitalized acute care patients admitted over a 6-month time period (September 2012 to March 2013).

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: During the study time period, 33,800 patient-days and 136 deteriorations were evaluated. Area under the curve ranged from 0.88 (surgical) to 0.94 (cardiac). Sensitivities for a Pediatric Early Warning Score greater than or equal to 3 ranged from 75% (surgical) to 94% (cardiology) and number needed to evaluate to find one deterioration was 11.5 (neurologic) to 43 patients (surgical). Sensitivities for a Pediatric Early Warning Score greater than or equal to 4 ranged from 54% (general medical) to 79% (hematology/oncology/bone marrow transplant) and number needed to evaluate of 5.5 (neurologic) to 12 patients (general medical). Sensitivities for a Pediatric Early Warning Score of greater than or equal to 5 ranged from 25% (surgical) to 58% (hematology/oncology/bone marrow transplant) and number needed to evaluate of 3.5 (cardiac, hematology/oncology/bone marrow transplant, neurologic) to eight patients (surgical).

CONCLUSIONS: An elevated Pediatric Early Warning Score is associated with ICU transfer and receipt of ICU-specific interventions in patients across different pediatric subspecialty patient populations.

Lung Rest During Extracorporeal Membrane Oxygenation for Neonatal Respiratory Failure-Practice Variations and Outcomes. (Duke)

Alapati D, et al. Lung Rest During Extracorporeal Membrane Oxygenation for Neonatal Respiratory Failure-Practice Variations and Outcomes. Pediatr Crit Care Med. 2017 Jul;18(7):667-674.

OBJECTIVE: Describe practice variations in ventilator strategies used for lung rest during extracorporeal membrane oxygenation for respiratory failure in neonates, and assess the potential impact of various lung rest strategies on the duration of extracorporeal membrane oxygenation and the duration of mechanical ventilation after decannulation.

DATA SOURCES: Retrospective cohort analysis from the Extracorporeal Life Support Organization registry database during the years 2008-2013.

STUDY SELECTION: All extracorporeal membrane oxygenation runs for infants less than or equal to 30 days of life for pulmonary reasons were included.

DATA EXTRACTION: Ventilator type and ventilator settings used for lung rest at 24 hours after extracorporeal membrane oxygenation initiation were obtained.

DATA SYNTHESIS: A total of 3,040 cases met inclusion criteria. Conventional mechanical ventilation was used for lung rest in 88% of cases and high frequency ventilation was used in 12%. In the conventional mechanical ventilation group, 32% used positive end-expiratory pressure strategy of 4-6 cm H2O (low), 22% used 7-9 cm H2O (mid), and 43% used 10-12 cm H2O (high). High frequency ventilation was associated with an increased mean (SEM) hours of extracorporeal membrane oxygenation (150.2 [0.05] vs 125 [0.02]; p < 0.001) and an increased mean (SEM) hours of mechanical ventilation after decannulation (135 [0.09] vs 100.2 [0.03]; p = 0.002), compared with conventional mechanical ventilation among survivors. Within the conventional mechanical ventilation group, use of higher positive end-expiratory pressure was associated with a decreased mean (SEM) hours of extracorporeal membrane oxygenation (high vs low: 136 [1.06] vs 156 [1.06], p = 0.001; mid vs low: 141 [1.06] vs 156 [1.06]; p = 0.04) but increased duration of mechanical ventilation after decannulation in the high positive end-expiratory pressure group compared with low positive end-expiratory pressure (p = 0.04) among survivors.

CONCLUSIONS: Wide practice variation exists with regard to ventilator settings used for lung rest during neonatal respiratory extracorporeal membrane oxygenation. Use of high frequency ventilation when compared with conventional mechanical ventilation and use of low positive end-expiratory pressure strategy when compared with mid positive end-expiratory pressure and high positive end-expiratory pressure strategy is associated with longer duration of extracorporeal membrane oxygenation. Further research to provide evidence to drive optimization of pulmonary management during neonatal respiratory extracorporeal membrane oxygenation is warranted.

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.