Mechanical ventilation for children with status asthmaticus

Anesthetic considerations in children with asthma

Due to the high prevalence of asthma and general airway reactivity, anesthesiologists frequently encounter children with asthma or asthma-like symptoms. This review focuses on the epidemiology, the underlying pathophysiology, and perioperative management of children with airway reactivity, including controlled and uncontrolled asthma. It spans from preoperative optimization to optimized intraoperative management, airway management, and ventilation strategies. There are three leading causes for bronchospasm (1) mechanical (eg, airway manipulation), (2) non-immunological anaphylaxis (anaphylactoid reaction), and (3) immunological anaphylaxis. Children with increased airway reactivity may benefit from a premedication with beta-2 agonists, non-invasive airway management, and deep removal of airway devices. While desflurane should be avoided in pediatric anesthesia due to an increased risk of bronchospasm, other volatile agents are potent bronchodilators. Propofol is superior in blunting airway reflexes and, therefore, well suited for anesthesia induction in children with increased airway reactivity.

Management of Children with Acute Asthma Attack: A RAND/UCLA Appropriateness Approach

Bronchial asthma is the most frequent chronic disease in children and affects up to 20% of the pediatric population, depending on the geographical area. Asthma symptoms vary over time and in intensity, and acute asthma attack can resolve spontaneously or in response to therapy. The aim of this project was to define the care pathway for pediatric patients who come to the primary care pediatrician or Emergency Room with acute asthmatic access. The project was developed in the awareness that for the management of these patients, broad coordination of interventions in the pre-hospital phase and the promotion of timely and appropriate assistance modalities with the involvement of all health professionals involved are important. Through the application of the RAND method, which obliges to discuss the statements derived from the guidelines, there was a clear increase in the concordance in the behavior on the management of acute asthma between primary care pediatricians and hospital pediatricians. The RAND method was found to be useful for the selection of good practices forming the basis of an evidence-based approach, and the results obtained form the basis for further interventions that allow optimizing the care of the child with acute asthma attack at the family and pediatric level. An important point of union between the primary care pediatrician and the specialist hospital pediatrician was the need to share spirometric data, also including the use of new technologies such as teleconsultation. Monitoring the progress of asthma through spirometry could allow the pediatrician in the area to intervene early by modifying the maintenance therapy and help the patient to achieve good control of the disease.

Overview of severe asthma, with emphasis on pediatric patients: a review for practitioners

Asthma is the most common life-threatening chronic disease in children. Although guidelines exist for the diagnosis and treatment of asthma, treatment of severe, pediatric asthma remains difficult. Limited studies in the pediatric population on new asthma therapies, complex issues with adolescence and adherence, health disparities, and unequal access to guideline-based care complicate the care of children with severe, persistent asthma. The purpose of this review is to provide an overview of asthma, including asthma subtypes, comorbidities, and risk factors, to discuss diagnostic considerations and pitfalls and existing treatments, and then present existing and emerging therapeutic approaches to asthma management. An improved understanding of asthma heterogeneity, clinical characteristics, inflammatory patterns, and pathobiology can help further guide the management of severe asthma in children. More studies are needed in the pediatric population to understand emerging therapeutics application in children. Effective multimodal strategies tailored to individual characteristics and a commitment to address risk factors, modifiers, and health disparities may help reduce the burden of asthma in the USA.

Emergency department treatment of asthma in children: A review

Asthma is the most common chronic illness in children, with >700,000 emergency department (ED) visits each year. Asthma is a respiratory disease characterized by a combination of airway inflammation, bronchoconstriction, bronchial hyperresponsiveness, and variable outflow obstruction, with clinical presentations ranging from mild to life-threatening. Standardized ED treatment can improve patient outcomes, including fewer hospital admissions. Informed by the most recent guidelines, this review focuses on the optimal approach to diagnosis and treatment of children with acute asthma exacerbations who present to the ED.

Anesthesia and ventilation strategies in children with asthma: part II - intraoperative management

PURPOSE OF REVIEW

As asthma is a frequent disease especially in children, anesthetists are increasingly providing anesthesia for children requiring elective surgery with well controlled asthma but also for those requiring urgent surgery with poorly controlled or undiagnosed asthma. This second part of this two-part review details the medical and ventilatory management throughout the perioperative period in general but also includes the perioperative management of acute bronchospasm and asthma exacerbations in children with asthma.

RECENT FINDINGS

Multiple observational trials assessing perioperative respiratory adverse events in healthy and asthmatic children provide the basis for identifying risk reduction strategies. Mainly, animal experiments and to a small extent clinical data have advanced our understanding of how anesthetic agents effect bronchial smooth muscle tone and blunt reflex bronchoconstriction. Asthma treatment outside anesthesia is well founded on a large body of evidence.Perioperative prevention strategies have increasingly been studied. However, evidence on the perioperative management, including mechanical ventilation strategies of asthmatic children, is still only fair, and further research is required.

SUMMARY

To minimize the considerable risk of perioperative respiratory adverse events in asthmatic children, perioperative management should be based on two main pillars: the preoperative optimization of asthma treatment (please refer to the first part of this two-part review) and - the focus of this second part of this review - the optimization of anesthesia management in order to optimize lung function and minimize bronchial hyperreactivity in the perioperative period.

Anesthesia and ventilation strategies in children with asthma: part I - preoperative assessment

PURPOSE OF REVIEW

Asthma is a common disease in the pediatric population, and anesthetists are increasingly confronted with asthmatic children undergoing elective surgery. This first of this two-part review provides a brief overview of the current knowledge on the underlying physiology and pathophysiology of asthma and focuses on the preoperative assessment and management in children with asthma. This also includes preoperative strategies to optimize lung function of asthmatic children undergoing surgery. The second part of this review focuses on the immediate perioperative anesthetic management including ventilation strategies.

RECENT FINDINGS

Multiple observational trials assessing perioperative respiratory adverse events in healthy and asthmatic children provide the basis for identifying risk factors in the patient's (family) history that aid the preoperative identification of at-risk children. Asthma treatment outside anesthesia is well founded on a large body of evidence. Optimization and to some extent intensifying asthma treatment can optimize lung function, reduce bronchial hyperreactivity, and minimize the risk of perioperative respiratory adverse events.

SUMMARY

To minimize the considerable risk of perioperative respiratory adverse events in asthmatic children, a good understanding of the underlying physiology is vital. Furthermore, a thorough preoperative assessment to identify children who may benefit of an intensified medical treatment thereby minimizing airflow obstruction and bronchial hyperreactivity is the first pillar of a preventive perioperative management of asthmatic children. The second pillar, an individually adjusted anesthesia management aiming to reduce perioperative adverse events, is discussed in the second part of this review.

A review of the use of adjunctive therapies in severe acute asthma exacerbation in critically ill children

Asthma is a common and potentially life threatening childhood condition. Asthma involves not only chronic airway remodeling, but may also include frequent exacerbations resulting from bronchospasm, edema, and mucus production. In children with severe exacerbations, standard therapy with β2-agonists, anti-cholinergic agents, oxygen, and systemic steroids may fail to reverse the severe airflow obstruction and necessitate use of adjunctive therapies. These therapies include intravenous or inhaled magnesium, inhaled helium-oxygen mixtures, intravenous methylxanthines, intravenous β2-agonists, and intravenous ketamine. Rarely, these measures are not successful and following the initiation of invasive mechanical ventilation, inhaled anesthetics or extracorporeal life support may be required. In this review, we discuss the mechanisms and evidence for adjunctive therapies in the setting of severe acute asthma exacerbations in children.

Demographics, clinical course, and outcomes of children with status asthmaticus treated in a pediatric intensive care unit: 8-year review

OBJECTIVE

This study was done to understand the demographics, clinical course, and outcomes of children with status asthmaticus treated in a tertiary care pediatric intensive care unit (PICU).

METHODS

The medical charts of all patients above 5 years of age admitted to the PICU at Nationwide Children's Hospital, Columbus, OH, USA, with status asthmaticus from 2000 to 2007 were reviewed retrospectively. Data from 222 encounters by 183 children were analyzed.

RESULTS

The mean age at admission in years was 11 ± 3.8. The median PICU stay was 1 day (range, 1-12 days) and median hospital stay was 3 days. The ventilated group (n = 17) stayed a median of 2 days longer in the PICU and hospital. Nearly half of the children (n = 91; 50%) did not receive daily controller asthma medications. Adherence to asthma medications was reported in 125 patient charts of whom 43 (34%) were compliant. Exposure to smoking was reported in 167 of whom 70 (42%) were exposed. Among patients receiving metered dose inhaler (MDI), only 39 (18%) were using it with a spacer. Among 105 patient charts asthma severity data were available, of them 21 (20%) were labeled as mild intermittent, 29 (28%) were mild persistent, 26 (25%) were moderate persistent, and 29 (28%) were severe persistent. Compared to children with only one PICU admission during the study period (n = 161), children who had multiple PICU admissions (n = 22) experienced more prior emergency department visits and hospitalizations for asthma symptoms. There were no fatalities.

CONCLUSION

Asthmatics with any disease severity are at risk for life-threatening asthma exacerbations requiring PICU stay, especially those who are not adherent with their daily medications.

Pediatric status asthmaticus

Status asthmaticus is a frequent cause of admission to a pediatric intensive care unit. Prompt assessment and aggressive treatment are critical. First-line or conventional treatment includes supplemental oxygen, aerosolized albuterol, and corticosteroids. There are several second-line treatments available; however, few comparative studies have been performed and in the absence of good evidence-based treatments, the use of these therapies is highly variable and dependent on local practice and provider preference. In this article the pathophysiology and treatment of status asthmaticus is discussed, and the literature regarding second-line treatments is critically assessed to apply an evidence basis to the treatment of this severe disease.

Trends in admissions for pediatric status asthmaticus in New Jersey over a 15-year period

OBJECTIVE

Status asthmaticus accounts for a large portion of the morbidity and mortality associated with asthma, but we know little about its epidemiology. We describe here the hospitalization characteristics of children with status asthmaticus, how they changed over time, and how they differed between hospitals with and without PICUs.

PATIENTS AND METHODS

We used administrative data from New Jersey that included all hospitalizations in the state from 1992, 1995, and 1999-2006. We identified children with status asthmaticus by using International Classification of Diseases, Ninth Revision, diagnosis codes that indicate status asthmaticus and the use of mechanical ventilation by using procedure codes. We designated hospitals with a PICU as "PICU hospitals" and those without as "adult hospitals."

RESULTS

We identified 28 309 admissions of children with status asthmaticus (22.8% of all asthma hospitalizations). From 1992 to 2006, the rate of hospital admissions decreased by half (from 1.98 in 1000 to 0.93 in 1000 children), and there was a 70% decrease in the number of children admitted to adult hospitals. The rate of ICU care in PICU hospitals more than tripled. However, the rate of mechanical ventilation remained low, and the number of deaths was small and unchanged (n=14 total). Hospital costs climbed from $6.6 million to $9.5 million.

CONCLUSIONS

Although fewer children are being admitted with status asthmaticus, the proportion of patients managed in PICUs is climbing. There has been no substantial change in rates of mechanical ventilation or death. Additional research is needed to better understand how patients and physicians decide on the appropriate site for hospital care and how that choice affects outcome.

Status asthmaticus in children

PURPOSE OF REVIEW

The prevalence of severe asthma in children has risen in the past few decades. The present review explores our current understanding of epidemiology, pathophysiology and treatment of status asthmaticus in children.

RECENT FINDINGS

The pathophysiology of inflammation and airway hyperactivity continues to be a source of research. Early initiation of inhaled beta-agonists and oral or parenteral steroids remain the standard of care in the treatment of status asthmaticus. Other treatment modalities such as magnesium and intravenous beta-agonists show some benefit. There is a resurgence of interest in the use of methylxanthines. Alternatives to endotracheal intubation show some promise in preventing respiratory failure.

SUMMARY

Asthma remains the third leading cause of hospitalization in children younger than 15 years old. Researchers continue to explore the efficacy of old and new treatment modalities. Future research efforts targeting at-risk populations could dramatically decrease asthma morbidity and mortality.

Isoflurane therapy for severe refractory status asthmaticus in children

OBJECTIVE

To describe the use of inhaled isoflurane in a series of children with life-threatening asthma.

DESIGN

Retrospective case series.

SETTING

Pediatric intensive care unit of a tertiary-care children's hospital. Ten children ranging in age from 1 to 16 years with 11 episodes of severe asthma requiring invasive mechanical ventilation in the pediatric intensive care unit over a 5-year period.

RESULTS

Isoflurane resulted in an improvement in arterial pH and a reduction in partial pressure of arterial carbon dioxide (PaCO(2)) in all the 11 instances. This effect was sustained in 10 cases and led to clinical improvement and rapid weaning from mechanical ventilation. One child failed to show sustained response and was placed on veno-venous extracorporeal membrane oxygenation. One child died secondary to anoxic brain injury sustained prior to hospitalization. Hypotension was the major side effect, and occurred in 8 children necessitating vasopressor support.

CONCLUSIONS

Isoflurane improves arterial pH and reduces partial pressure of arterial carbon dioxide in mechanically ventilated children with life-threatening status asthmaticus who are not responsive to conventional management.

Acute severe asthma: differences in therapies and outcomes among pediatric intensive care units

OBJECTIVE

To determine differences in therapies and outcomes among pediatric intensive care units for patients with acute severe asthma.

DESIGN

Retrospective cohort study.

SETTING

Eleven pediatric intensive care units participating in the Pediatric Intensive Care Evaluations.

PATIENTS

Patients were 1528 children with a primary diagnosis of asthma.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We studied severity of illness, length of stay, and use of invasive interventions. The patients at the centers had similar median physiologic measures of illness and Pediatric Risk of Mortality III scores. The patients received a wide range of invasive interventions depending on institution, including mechanical ventilation (3% to 47%), arterial catheter placement (4% to 46%), central venous catheter (2% to 51%), and determination of a blood gas (24% to 70%). At institutions where mechanical ventilation was used more commonly (>20%, high use), intensive care and hospital stays were longer for asthmatic patients regardless of mechanical ventilation requirement compared with centers with lower use of mechanical ventilation. The status of "high-use center" was an independent predictor for intensive care stay (p = .005) and hospital length of stay (p = .017) as well as duration of mechanical ventilation (p = .014) after adjustment for age, degree of hypercarbia, maximal respiratory rate, use of an arterial catheter, and Pediatric Risk of Mortality III scores among ventilated children.

CONCLUSIONS

We found that use of invasive interventions including mechanical ventilation and vascular monitoring varied greatly by institution. Centers with higher use of mechanical ventilation had longer median intensive care stay and hospital stays. Pediatric asthma management for acute severe asthma may be improved by clear elucidation of the institutional practices where fewer invasive interventions were used to achieve better outcomes.

Status asthmaticus in children: a review

About 10% of American children have asthma, and its prevalence, morbidity, and mortality have been increasing. Asthma is an inflammatory disease with edema, bronchial constriction, and mucous plugging. Status asthmaticus in children requires aggressive treatment with beta-agonists, anticholinergics, and corticosteroids. Intubation and mechanical ventilation should be avoided if at all possible, as the underlying dynamic hyperinflation will worsen with positive-pressure ventilation. If mechanical ventilation becomes necessary, controlled hypoventilation with low tidal volume and long expiratory time may lessen the risk of barotrauma and hypotension. Unusual and nonestablished therapies for severe asthma are discussed.

Acute asthma

OBJECTIVE: Asthma is the most common medical emergency in children. It is associated with significant morbidity and mortality rates and poses a tremendous societal burden worldwide. Management of the acute attack involves a stepwise approach that includes beta-agonist and steroid therapy, the mainstay of emergency treatment. Most patients will respond to this regime and can be discharged from the emergency department. Failure to respond to treatment necessitates hospital admission and sometimes admission to the intensive care unit (ICU). Management in the ICU involves intensification of pharmacologic therapy, including nonstandard therapies, in an attempt to avoid intubation and ventilation. When needed, mechanical ventilatory support can be rendered fairly safe with little morbidity if the likely cardiorespiratory physiologic derangements are appreciated and if appropriate ventilatory strategies are used. In the past two decades, the availability of newer potent medications and changes in approach to monitoring and ventilatory strategies have resulted in a decrease in ICU morbidity and mortality rates. Research endeavors are presently underway to further characterize the underlying mechanisms of the disease and are likely to lead to novel therapies. This article reviews the approach to management of acute severe asthma.