Christopher J. L. Newth

Cuffed endotracheal tubes in pediatric intensive care

We prospectively studied 282 consecutive tracheal intubations (243 patients) in a pediatric intensive care unit during a 7-month period to compare cuffed and uncuffed endotracheal tube (ETT) utilization and outcome. The incidence of postextubation stridor in each ETT group was the major outcome measure after controlling for various patient risk factors. Patients whose ETTs were inserted in the operating room, who were less than 1 year of age, or who had ETTs in place for less than 72 hours were more likely to have had insertion of an uncuffed ETT. Patients whose ETTs were inserted in the emergency department or who were more than 5 years of age were more likely to have had insertion of a cuffed ETT. Those who had a cuffed ETT were older (mean 8.1 vs 2.5 years) and had ETTs in place longer (mean 6.1 vs 3.7 days) than patients with an uncuffed ETT. Of the 188 patients who subsequently had removal of their ETTs, the overall incidence of postextubation stridor was 14.9%, with no significant difference between the two ETT groups even after controlling for patient age, duration of intubation, trauma, leak around ETT before extubation, and pediatric risk of mortality score. Two patients in the cuffed ETT group and four patients in the uncuffed ETT group required reintubation for severe postextubation stridor. Long-term follow-up identified 33 patients (17%) who required hospital readmission. None of these was admitted with an upper airway problem. Two patients who previously had insertion of a cuffed ETT subsequently received tracheostomies for the primary purpose of long-term mechanical ventilation unrelated to any problem with the upper airway. We conclude that cuffed endotracheal intubation is not associated with an increased risk of postextubation stridor or significant long-term sequelae.

Therapeutic Hypothermia after Out-of-Hospital Cardiac Arrest in Children

BACKGROUND Therapeutic hypothermia is recommended for comatose adults after witnessed out-of-hospital cardiac arrest, but data about this intervention in children are limited. METHODS We conducted this trial of two targeted temperature interventions at 38 childrens hospitals involving children who remained unconscious after out-of-hospital cardiac arrest. Within 6 hours after the return of circulation, comatose patients who were older than 2 days and younger than 18 years of age were randomly assigned to therapeutic hypothermia (target temperature, 33.0°C) or therapeutic normothermia (target temperature, 36.8°C). The primary efficacy outcome, survival at 12 months after cardiac arrest with a Vineland Adaptive Behavior Scales, second edition (VABS-II), score of 70 or higher (on a scale from 20 to 160, with higher scores indicating better function), was evaluated among patients with a VABS-II score of at least 70 before cardiac arrest. RESULTS A total of 295 patients underwent randomization. Among the 260 patients with data that could be evaluated and who had a VABS-II score of at least 70 before cardiac arrest, there was no significant difference in the primary outcome between the hypothermia group and the normothermia group (20% vs. 12%; relative likelihood, 1.54; 95% confidence interval [CI], 0.86 to 2.76; P=0.14). Among all the patients with data that could be evaluated, the change in the VABS-II score from baseline to 12 months was not significantly different (P=0.13) and 1-year survival was similar (38% in the hypothermia group vs. 29% in the normothermia group; relative likelihood, 1.29; 95% CI, 0.93 to 1.79; P=0.13). The groups had similar incidences of infection and serious arrhythmias, as well as similar use of blood products and 28-day mortality. CONCLUSIONS In comatose children who survived out-of-hospital cardiac arrest, therapeutic hypothermia, as compared with therapeutic normothermia, did not confer a significant benefit in survival with a good functional outcome at 1 year. (Funded by the National Heart, Lung, and Blood Institute and others; THAPCA-OH ClinicalTrials.gov number, NCT00878644.).

Extubation failure in pediatric intensive care: A multiple-center study of risk factors and outcomes

ObjectiveTo determine a contemporary failed extubation rate, risk factors, and consequences of extubation failure in pediatric intensive care units (PICUs). Three hypotheses were investigated: a) Extubation failure is in part disease specific; b) preexisting respiratory conditions predispose to extubation failure; and c) admission acuity scoring does not affect extubation failure. DesignTwelve-month prospective, observational, clinical study. SettingSixteen diverse PICUs in the United States. PatientsPatients were 2,794 patients from the newborn period to 18 yrs of age experiencing a planned extubation trial. InterventionsNone. Measurements and Main ResultsA descriptive statistical analysis was performed, and outcome differences of the failed extubation population were determined. The extubation failure rate was 6.2% (174 of 2,794; 95% confidence interval, 5.3–7.1). Patient features associated with extubation failure (p < .05) included age ≤24 months; dysgenetic condition; syndromic condition; chronic respiratory disorder; chronic neurologic condition; medical or surgical airway condition; chronic noninvasive positive pressure ventilation; the need to replace the endotracheal tube on admission to the PICU; and the use of racemic epinephrine, steroids, helium-oxygen therapy (heliox), or noninvasive positive pressure ventilation within 24 hrs of extubation. Patients failing extubation had longer pre-extubation intubation time (failed, 148.7 hrs, sd ± 207.8 vs. success, 107.9 hrs, sd ± 171.3; p < .001), longer PICU length of stay (17.5 days, sd ± 15.6 vs. 7.6 days, sd ± 11.1; p < .001), and a higher mortality rate than patients not failing extubation (4.0% vs. 0.8%; p < .001). Failure was found to be in part disease specific, and preexisting respiratory conditions were found to predispose to failure whereas admission acuity did not. ConclusionA variety of patient features are associated with an increase in extubation failure rate, and serious outcome consequences characterize the extubation failure population in PICUs.

Tolerance and Withdrawal From Prolonged Opioid Use in Critically Ill Children

OBJECTIVE: After prolonged opioid exposure, children develop opioid-induced hyperalgesia, tolerance, and withdrawal. Strategies for prevention and management should be based on the mechanisms of opioid tolerance and withdrawal. PATIENTS AND METHODS: Relevant manuscripts published in the English language were searched in Medline by using search terms “opioid,” “opiate,” “sedation,” “analgesia,” “child,” “infant-newborn,” “tolerance,” “dependency,” “withdrawal,” “analgesic,” “receptor,” and “individual opioid drugs.” Clinical and preclinical studies were reviewed for data synthesis. RESULTS: Mechanisms of opioid-induced hyperalgesia and tolerance suggest important drug- and patient-related risk factors that lead to tolerance and withdrawal. Opioid tolerance occurs earlier in the younger age groups, develops commonly during critical illness, and results more frequently from prolonged intravenous infusions of short-acting opioids. Treatment options include slowly tapering opioid doses, switching to longer-acting opioids, or specifically treating the symptoms of opioid withdrawal. Novel therapies may also include blocking the mechanisms of opioid tolerance, which would enhance the safety and effectiveness of opioid analgesia. CONCLUSIONS: Opioid tolerance and withdrawal occur frequently in critically ill children. Novel insights into opioid receptor physiology and cellular biochemical changes will inform scientific approaches for the use of opioid analgesia and the prevention of opioid tolerance and withdrawal.

Pediatric Acute Respiratory Distress Syndrome: Consensus Recommendations From the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE To describe the final recommendations of the Pediatric Acute Lung Injury Consensus Conference. DESIGN Consensus conference of experts in pediatric acute lung injury. SETTING Not applicable. SUBJECTS PICU patients with evidence of acute lung injury or acute respiratory distress syndrome. INTERVENTIONS None. METHODS A panel of 27 experts met over the course of 2 years to develop a taxonomy to define pediatric acute respiratory distress syndrome and to make recommendations regarding treatment and research priorities. When published, data were lacking a modified Delphi approach emphasizing strong professional agreement was used. MEASUREMENTS AND MAIN RESULTS A panel of 27 experts met over the course of 2 years to develop a taxonomy to define pediatric acute respiratory distress syndrome and to make recommendations regarding treatment and research priorities. When published data were lacking a modified Delphi approach emphasizing strong professional agreement was used. The Pediatric Acute Lung Injury Consensus Conference experts developed and voted on a total of 151 recommendations addressing the following topics related to pediatric acute respiratory distress syndrome: 1) Definition, prevalence, and epidemiology; 2) Pathophysiology, comorbidities, and severity; 3) Ventilatory support; 4) Pulmonary-specific ancillary treatment; 5) Nonpulmonary treatment; 6) Monitoring; 7) Noninvasive support and ventilation; 8) Extracorporeal support; and 9) Morbidity and long-term outcomes. There were 132 recommendations with strong agreement and 19 recommendations with weak agreement. Once restated, the final iteration of the recommendations had none with equipoise or disagreement. CONCLUSIONS The Consensus Conference developed pediatric-specific definitions for acute respiratory distress syndrome and recommendations regarding treatment and future research priorities. These are intended to promote optimization and consistency of care for children with pediatric acute respiratory distress syndrome and identify areas of uncertainty requiring further investigation.

Weaning and extubation readiness in pediatric patients.

Objective: A systematic review of weaning and extubation for pediatric patients on mechanical ventilation. Data Selection: Pediatric and adult literature, English language. Study Selection: Invited review. Data Sources: Literature review using National Library of Medicine PubMed from January 1972 until April 2008, earlier cross-referenced article citations, the Cochrane Database of Systematic Reviews, and the Internet. Conclusions: Despite the importance of minimizing time on mechanical ventilation, only limited guidance on weaning and extubation is available from the pediatric literature. A significant proportion of patients being evaluated for weaning are actually ready for extubation, suggesting that weaning is often not considered early enough in the course of ventilation. Indications for extubation are even less clear, although a trial of spontaneous breathing would seem a prerequisite. Several indices have been developed in an attempt to predict weaning and extubation success but the available literature would suggest they offer no improvement over clinical judgment. Extubation failure rates range from 2% to 20% and bear little relationship to the duration of mechanical ventilation. Upper airway obstruction is the single most common cause of extubation failure. A reliable method of assessing readiness for weaning and predicting extubation success is not evident from the pediatric literature.

High-frequency oscillatory ventilation in pediatric respiratory failure: A multicenter experience

ObjectiveThe use of high-frequency oscillatory ventilation (HFOV) has increased dramatically in the management of respiratory failure in pediatric patients. We surveyed ten pediatric centers that frequently use high-frequency oscillation to describe current clinical practice and to examine factors related to improved outcomes. DesignRetrospective, observational questionnaire study. SettingTen tertiary care pediatric intensive care units. PatientsTwo hundred ninety patients managed with HFOV between January 1997 and June 1998. InterventionsNone. Measurements and Main ResultsPatients were classified according to presence or absence of preexisting lung disease, symptomatic respiratory syncytial virus infection, or presence of cyanotic heart disease or residual right-to-left intracardiac shunt. In addition, patients for whom HFOV acutely failed were analyzed separately. Those patients with preexisting lung disease were significantly smaller, had a significantly higher incidence of pulmonary infection as the triggering etiology, and had a significantly greater duration of conventional ventilation before institution of HFOV compared with patients without preexisting lung disease. Stepwise logistic regression was used to predict mortality and the occurrence of chronic lung disease in survivors. In patients without preexisting lung disease, the model predicted a 70% probability of death when the oxygenation index (OI) after 24 hrs was 28 in the immunocompromised patients and 64 in the patients without immunocompromise. In the immunocompromised patients, the model predicted a 90% probability of death when the OI after 24 hrs was 58. In survivors without preexisting lung disease, the model predicted a 70% probability of developing chronic lung disease when the OI at 24 hrs was 31 in the patients with sepsis syndrome and 50 in the patients without sepsis syndrome. In the patients with sepsis syndrome, the model predicted a 90% probability of developing chronic lung disease when the OI at 24 hrs was 45. ConclusionsGiven the number of centers involved and the size of the database, we feel that our results broadly reflect current practice in the use of HFOV in pediatric patients. These results may help in deciding which patients are most likely to benefit from aggressive intervention by using extracorporeal techniques and may help identify high-risk populations appropriate for prospective study of innovative modes of supporting gas exchange (e.g., partial liquid breathing or intratracheal pulmonary ventilation).

Parents' perspectives on physician-parent communication near the time of a child's death in the pediatric intensive care unit

Objective: Communicating bad news about a child’s illness is a difficult task commonly faced by intensive care physicians. Greater understanding of parents’ scope of experiences with bad news during their child’s hospitalization will help physicians communicate more effectively. Our objective is to describe parents’ perceptions of their conversations with physicians regarding their child’s terminal illness and death in the pediatric intensive care unit (PICU). Design: A secondary analysis of a qualitative interview study. Setting: Six children’s hospitals in the National Institute of Child Health and Human Development Collaborative Pediatric Critical Care Research Network. Participants: Fifty-six parents of 48 children who died in the PICU 3–12 months before the study. Interventions: Parents participated in audio recorded semistructured telephone interviews. Interviews were analyzed using established qualitative methods. Measurements and Main Results: Of the 56 parents interviewed, 40 (71%) wanted to provide feedback on the way information about their child’s terminal illness and death was communicated by PICU physicians. The most common communication issue identified by parents was the physicians’ availability and attentiveness to their informational needs. Other communication issues included honesty and comprehensiveness of information, affect with which information was provided, withholding of information, provision of false hope, complexity of vocabulary, pace of providing information, contradictory information, and physicians’ body language. Conclusions: The way bad news is discussed by physicians is extremely important to most parents. Parents want physicians to be accessible and to provide honest and complete information with a caring affect, using lay language, and at a pace in accordance with their ability to comprehend. Withholding prognostic information from parents often leads to false hopes and feelings of anger, betrayal, and distrust. Future research is needed to investigate whether the way bad news is discussed influences psychological adjustment and family functioning among bereaved parents.

Acute respiratory distress syndrome caused by respiratory syncytial virus

Acute respiratory distress syndrome (ARDS) complicating severe respiratory syncytial virus (RSV) infection has been described in only a few infants. In contrast to the low mortality rates usually associated with RSV infections (<5%), mortality rates in the range of 40–70% have been reported in pediatric patients with ARDS. However, studies on patients with ARDS are usually lumped with respect to causation, and the disease course of RSV‐induced ARDS has not been previously studied. We examined the pulmonary function abnormalities of 37 infants with RSV‐induced respiratory failure who were admitted to our pediatric intensive care unit for assisted ventilation. Measurements included respiratory mechanics, maximum expiratory flow‐volume curves, and lung volumes. These allowed the calculation of a Murray lung injury score (modified for pediatric use) in which radiographic findings, ventilator settings, lung compliance, and blood gas results were considered. We identified ten infants with severe restrictive lung disease who fulfilled the clinical criteria for classification as ARDS. All had lung injury scores above 2.5, compatible with a diagnosis of ARDS. Twenty‐seven infants had obstructive patterns of lung function consistent with a clinical diagnosis of RSV bronchiolitis. The patients with RSV‐induced ARDS were significantly younger, and had a longer time on assisted ventilation (P < 0.05) and a higher proportion of predisposing illnesses (P < 0.05, odds ratio = 6.67, two‐tailed Fishers exact test) when compared with the patients who had obstructive disease. Only one patient (who had immunodeficiency) died, and all others were successfully managed on conventional mechanical ventilation. We conclude that RSV‐induced respiratory failure represents a relatively benign cause of ARDS in pediatric patients. Our observations support the notion of differentiating ARDS with respect to causation, especially when novel and experimental therapy is considered and mortality rates are analyzed. Pediatr. Pulmonol. 1997; 23:176–183

Acute lung injury in children: Therapeutic practice and feasibility of international clinical trials*

Objectives: To describe mechanical ventilation strategies in acute lung injury and to estimate the number of eligible patients for clinical trials on mechanical ventilation management. In contrast to adult medicine, there are few clinical trials to guide mechanical ventilation management in children with acute lung injury. Design: A cross-sectional study for six 24-hr periods from June to November 2007. Setting: Fifty-nine pediatric intensive care units in 12 countries in North America and Europe. Patients: We identified children meeting acute lung injury criteria and collected detailed information on illness severity, mechanical ventilatory support, and use of adjunctive therapies. Interventions: None. Measurements and Main Results: Of 3823 patients screened, 414 (10.8%) were diagnosed with acute lung injury by their treating physician, but only 165 (4.3%) patients met prestablished inclusion/exclusion criteria to this trial and, therefore, would have been eligible for a clinical trial. Of these, 124 (75.2%) received conventional mechanical ventilation, 27 (16.4%) received high-frequency oscillatory ventilation, and 14 (8.5%) received noninvasive mechanical ventilation. In the conventional mechanical ventilation group, 43.5% were ventilated in a pressure control mode with a mean tidal volume of 8.3 ± 3.3 mL/kg; and there was no clear relationship between positive end-expiratory pressure and Fio2 delivery in the conventional mechanical ventilation group. Use of adjunctive treatments, including nitric oxide, prone positioning, surfactant, hemofiltration, recruitment maneuvers, steroids, bronchodilators, and fluid restriction, was highly variable. Conclusions: Our study reveals inconsistent mechanical ventilation practice and use of adjunctive therapies in children with acute lung injury. Pediatric clinical trials assessing mechanical ventilation management are needed to generate evidence to optimize outcomes. We estimate that a large number of centers (∼60) are needed to conduct such trials; it is imperative, therefore, to bring about international collaboration.