Tratamento atual de crianças com asma crítica e quase fatal / Contemporary treatment of children with critical and near-fatal asthma

RESUMO A asma é a mais comum das doenças da infância. Embora a maioria das crianças com exacerbações agudas de asma não demanda cuidados críticos, algumas delas não respondem ao tratamento padrão e necessitam de cuidados mais intensos. Crianças com asma crítica ou quase fatal precisam de monitoramento estrito quanto à deterioração e podem requerer estratégias terapêuticas agressivas. Esta revisão examinou as evidências disponíveis que dão suporte a terapias para asma crítica e quase fatal, e resumiu o cuidado clínico atual para essas crianças. O tratamento típico inclui uso parenteral de corticosteroides e fármacos beta-agonistas, por via inalatória ou intravenosa. Para crianças com resposta inadequada ao tratamento padrão, pode-se lançar mão do uso inalatório de brometo de ipratrópio ou intravenoso de sulfato de magnésio, metilxantinas e misturas gasosas com hélio, além de suporte ventilatório mecânico não invasivo. Pacientes com insuficiência respiratória progressiva se beneficiam de ventilação mecânica com uma estratégia que emprega grandes volumes correntes e baixas frequências do ventilador, para minimizar a hiperinsuflação dinâmica, o barotrauma e a hipotensão. Sedativos, analgésicos e bloqueadores neuromusculares são frequentemente necessários na fase inicial do tratamento para facilitar um estado de hipoventilação controlada e hipercapnia permissiva. Pacientes que não conseguem melhorar com a ventilação mecânica podem ser considerados para abordagens menos comuns, como inalação de anestésicos, broncoscopia e suporte extracorpóreo à vida. Esta abordagem atual resultou em taxas de mortalidade extremamente baixas, mesmo em crianças com necessidade de suporte mecânico.

ABSTRACT Asthma is the most common chronic illness in childhood. Although the vast majority of children with acute asthma exacerbations do not require critical care, some fail to respond to standard treatment and require escalation of support. Children with critical or near-fatal asthma require close monitoring for deterioration and may require aggressive treatment strategies. This review examines the available evidence supporting therapies for critical and near-fatal asthma and summarizes the contemporary clinical care of these children. Typical treatment includes parenteral corticosteroids and inhaled or intravenous beta-agonist drugs. For children with an inadequate response to standard therapy, inhaled ipratropium bromide, intravenous magnesium sulfate, methylxanthines, helium-oxygen mixtures, and non-invasive mechanical support can be used. Patients with progressive respiratory failure benefit from mechanical ventilation with a strategy that employs large tidal volumes and low ventilator rates to minimize dynamic hyperinflation, barotrauma, and hypotension. Sedatives, analgesics and a neuromuscular blocker are often necessary in the early phase of treatment to facilitate a state of controlled hypoventilation and permissive hypercapnia. Patients who fail to improve with mechanical ventilation may be considered for less common approaches, such as inhaled anesthetics, bronchoscopy, and extracorporeal life support. This contemporary approach has resulted in extremely low mortality rates, even in children requiring mechanical support.

Validation of a pediatric bedside tool to predict time to death after withdrawal of life support.

AIM: To evaluate the accuracy of a tool developed to predict timing of death following withdrawal of life support in children. METHODS: Pertinent variables for all pediatric deaths (age ≤ 21 years) from 1/2009 to 6/2014 in our pediatric intensive care unit (PICU) were extracted through a detailed review of the medical records. As originally described, a recently developed tool that predicts timing of death in children following withdrawal of life support (dallas predictor tool [DPT]) was used to calculate individual scores for each patient. Individual scores were calculated for prediction of death within 30 min (DPT30) and within 60 min (DPT60). For various resulting DPT30 and DPT60 scores, sensitivity, specificity and area under the receiver operating characteristic curve were calculated. RESULTS: There were 8829 PICU admissions resulting in 132 (1.5%) deaths. Death followed withdrawal of life support in 70 patients (53%). After excluding subjects with insufficient data to calculate DPT scores, 62 subjects were analyzed. Average age of patients was 5.3 years (SD: 6.9), median time to death after withdrawal of life support was 25 min (range; 7 min to 16 h 54 min). Respiratory failure, shock and sepsis were the most common diagnoses. Thirty-seven patients (59.6%) died within 30 min of withdrawal of life support and 52 (83.8%) died within 60 min. DPT30 scores ranged from -17 to 16. A DPT30 score ≥ -3 was most predictive of death within that time period, with sensitivity = 0.76, specificity = 0.52, AUC = 0.69 and an overall classification accuracy = 66.1%. DPT60 scores ranged from -21 to 28. A DPT60 score ≥ -9 was most predictive of death within that time period, with sensitivity = 0.75, specificity = 0.80, AUC = 0.85 and an overall classification accuracy = 75.8%. CONCLUSION: In this external cohort, the DPT is clinically relevant in predicting time from withdrawal of life support to death. In our patients, the DPT is more useful in predicting death within 60 min of withdrawal of life support than within 30 min. Furthermore, our analysis suggests optimal cut-off scores. Additional calibration and modifications of this important tool could help guide the intensive care team and families considering DCD.

Implementation of a diuretic stewardship program in a pediatric cardiovascular intensive care unit to reduce medication expenditures.

PURPOSE: The implementation of a diuretic stewardship program in a pediatric cardiovascular intensive care unit (ICU) is described. METHODS: This retrospective study compared the use of i.v. chlorothiazide and i.v. ethacrynic acid in pediatric cardiovascular surgery patients before and after implementation of a diuretic stewardship program. All pediatric patients admitted to the pediatric cardiovascular service were included. The cardiovascular surgery service was educated on formal indications for specific diuretic agents, and the diuretic stewardship program was implemented on January 1, 2013. Under the stewardship program, i.v. ethacrynic acid was indicated in patients with a sulfonamide allergy, and i.v. chlorothiazide was considered appropriate in patients receiving maximized i.v. loop diuretic doses. A detailed review of the pharmacy database and medical records was performed for each patient to determine i.v. chlorothiazide and i.v. ethacrynic acid use and expenditures, appropriateness of use, days using a ventilator, and cardiovascular ICU length of stay. RESULTS: After implementation of diuretic stewardship, the use of i.v. chlorothiazide decreased by 74% (531 fewer doses) while i.v. ethacrynic acid use decreased by 92% (47 fewer doses), resulting in a total reduction of $91,398 in expenditures on these diuretics over the six-month study period and an estimated annual saving of over $182,000. The median number of days using a ventilator and the length of ICU stay did not differ significantly during the study period. CONCLUSION: Implementation of a diuretic stewardship program reduced the use of i.v. chlorothiazide and i.v. ethacrynic acid without adversely affecting clinical outcomes such as ventilator days and length of stay in a pediatric cardiovascular ICU.

Implementation of continuous capnography is associated with a decreased utilization of blood gases.

BACKGROUND: Capnography provides a continuous, non-invasive monitoring of the CO2 to assess adequacy of ventilation and provide added safety features in mechanically ventilated patients by allowing for quick identification of unplanned extubation. These monitors may allow for decreased utilization of blood gases. The objective was to determine if implementation of continuous capnography monitoring decreases the utilization of blood gases resulting in decreased charges. METHODS: This is a retrospective review of a quality improvement project that compares the utilization of blood gases before and after the implementation of standard continuous capnography. The time period of April 2010 to September 2010 was compared to April 2011 to September 2011. Parameters collected included total number of blood gases analyzed, cost of blood gas analysis, ventilator and patient days. RESULTS: The total number of blood gases after the institution of end tidal CO2 monitoring decreased from 12,937 in 2009 and 13,171 in 2010 to 8,070 in 2011. The average number of blood gases per encounter decreased from 20.8 in 2009 and 21.6 in 2010 to 13.8 post intervention. The blood gases per ventilator day decreased from 4.94 in 2009 and 4.76 in 2010 to 3.30 post intervention. The total charge savings over a 6-month period was $880,496. CONCLUSIONS: Continuous capnography resulted in a significant savings over a 6-month period by decreasing the utilization of blood gas measurements.

Fatalities above 30,000 feet: characterizing pediatric deaths on commercial airline flights worldwide.

OBJECTIVES: We conducted this study to characterize in-flight pediatric fatalities onboard commercial airline flights worldwide and identify patterns that would have been unnoticed through single case analysis of these relative rare events. DESIGN: Retrospective cohort study of pediatric in-flight medical emergencies resulting in fatalities between January 2010 and June 2013. SETTING: A ground-based medical support center providing remote medical support to commercial airlines worldwide. PATIENTS: Children (age 0-18 yr) who experienced a medical emergency resulting in death during a commercial airline flight. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were a total of 7,573 in-flight medical emergencies involving children reported to the ground-based medical support center, resulting in 10 deaths (0.13% of all pediatric in-flight emergencies). The median subject age was 3.5 months with 90% being younger than 2 years, the age until which children are allowed to travel sharing a seat with an adult passenger, also known as lap infants. Six patients had no previous medical history, with one suffering cardiorespiratory arrest after developing acute respiratory distress during flight and five found asystolic (including four lap infants). Four subjects had preflight medical conditions, including two children traveling for the purpose of accessing advanced medical care. CONCLUSIONS: Pediatric in-flight fatalities are rare, but death occurs most commonly in infants and in subjects with a preexisting medical condition. The number of fatalities involving seemingly previously healthy children under the age of 2 years (lap infants) is intriguing and could indicate a vulnerable population at increased risk of death related to in-flight environmental factors, sleeping arrangements, or yet another unrecognized factor.

Alteplase use for malfunctioning central venous catheters correlates with catheter-associated bloodstream infections.

OBJECTIVES: A catheter thrombosis and the presence of a catheter-associated bloodstream infection (CBSI) often occur simultaneously, but it is unclear if or to what degree the two complications relate. Several animal and adult studies indicate a relationship between fibrin sheaths and thrombi in the development of CBSIs. To date, there has been limited human investigation in the pediatric population to determine a clear link between the presence of a thrombus and bacteremia. The use of alteplase for malfunctioning central venous catheter may indicate the formation of intraluminal thrombus or fibrin sheath. A catheter that requires alteplase is at higher risk of a CBSI. DESIGN: A retrospective chart review from July 2008 to December 2010. SETTING: PICU. PATIENTS: All patients with central catheters admitted to the PICU. INTERVENTIONS: No interventions performed with the retrospective study. MEASUREMENTS: Number of total central venous catheters, number of central venous catheters that received treatment with alteplase, and number of CBSIs. MAIN RESULTS: Preliminary data during the study period identified 3,289 central venous catheters. Twelve percent of these catheters required at least one dose of alteplase. There were 40 CBSIs during this same time period of which 28% received alteplase during the 5 days preceding the positive blood culture. The odds ratio for getting a CBSI when alteplase is administered is 2.87 (confidence interval 1.42-5.80; p = 0.002). The average age of the central venous catheters at time of infection was not statistically different, 16.1 days in the alteplase catheters compared with 25.6 days for the catheters that did not receive alteplase (p = 0.6). CONCLUSIONS: There is a positive correlation between the use of alteplase for malfunctioning central venous catheters and the development of a CASBI. This is likely associated with the presence of an intraluminal fibrin sheath or thrombus. This study adds evidence linking thrombus formation to CBSI.

Post-transplant critical care outcomes for pediatric multivisceral and intestinal transplant patients.

This study reviews the post-operative management of pediatric intestinal transplant patients at a single center with reporting of standard PICU benchmarks for quality of care. It is a retrospective, descriptive, chart review describing our institution's experience between 2006 and 2010. Twenty patients were included. Median age at transplant was 1.6 yr. Median length of PICU stay was 12 days. Median ventilation time was two days. Median time for continuous sedation infusion was two days, with median continuous pain medication infusion of three days. All patients were placed on parental nutrition and started on enteral feedings between days 3 and 4. Forty percent of patients required hemodynamic support. Only 35% of patients required insulin therapy. Diuretics were frequently used in this patient population. There were no episodes of early rejection. The survival rate to PICU discharge was 95%. Our institution's experience over the past four yr has been very successful with a short duration of mechanical ventilation, limited use of pain and sedation drips, early initiation of enteral feedings, minimal hemodynamic support, and a low mortality rate to PICU discharge despite a preponderance of complex MVTx recipients.

Oxygenation index predicts mortality in pediatric stem cell transplant recipients requiring mechanical ventilation.

The mortality in the ICU for pediatric HSCT recipients remains high. Early pulmonary complications continue to be an obstacle to the survival. We hypothesize OI is a predictor for mortality in critically ill pediatric HSCT recipients. Retrospective review of pediatric HSCT recipients between 2002 and 2010 who required intensive care during the same hospital admission as their transplant. Twenty-eight patients accounted for 31 ICU admissions. Twenty-six (84%) admissions required mechanical ventilation. Ten (38%) mechanically ventilated admissions were placed on HFOV. Mortality of those mechanically ventilated was 70%. An OI ≥ 20 at any point during ventilation was associated with 94% mortality, while an OI ≥ 25 had 100% mortality. There was a significant association between maximum OI at any point during mechanical ventilation and ICU mortality, with the odds of dying increasing by 13% for each unit increase of max OI (OR = 1.13, 95% CI = 1.01-1.26, p = 0.03). An OI of 20 had a sensitivity of 0.89 and specificity of 0.83 for predicting mortality. OI has a strong association with ICU mortality among pediatric stem cell recipients.