Randomised controlled trial of aminophylline for severe acute asthma

AARC and PALISI Clinical Practice Guideline: Pediatric Critical Asthma

To address the lack of guidance for clinicians in their care of children with critical asthma, a multidisciplinary team of medical providers used Grading of Recommendations, Assessment, Development, and Evaluation methodology to make the following recommendations: 1. We suggest the use of continuous inhaled short-acting β agonist (SABA) over frequent intermittent SABA in children treated for critical asthma. (Conditional recommendation, very low certainty of evidence) 2. We suggest the use of either high- or low-dose continuous inhaled SABA regimens in children treated for critical asthma. (Conditional recommendation, very low certainty of evidence) 3. We suggest the use of either dexamethasone or methylprednisolone (or an equivalent dose of prednisone/prednisolone) for children treated for critical asthma. (Conditional recommendation, very low certainty of evidence) 4. We suggest the use of intravenous (IV) magnesium (intermittent or continuous) as an adjunct therapy in children treated for critical asthma. (Conditional recommendation, low certainty of evidence) 5. We cannot recommend for or against the use of IV methylxanthines as an adjunct therapy in children treated for critical asthma. (Conditional recommendation, very low certainty of evidence) 6. We suggest the use of an IV SABA infusion as an adjunct therapy in children treated for critical asthma. (Conditional recommendation, low certainty of evidence) 7. We cannot recommend for or against the application of high-flow nasal cannula versus conventional oxygen therapy in children presenting with critical asthma with persistent hypoxemia and/or respiratory distress. (Conditional recommendation, very low certainty of evidence) 8. We suggest the use of bi-level positive airway pressure over conventional oxygen therapy in children presenting with critical asthma with persistent hypoxemia and/or respiratory distress. (Conditional recommendation, very low certainty of evidence) 9. We cannot recommend for or against the application of bi-level positive airway pressure over high-flow nasal cannula for children hospitalized with critical asthma with persistent hypoxemia and/or respiratory distress. (Conditional recommendation, very low certainty of evidence) 10. We cannot recommend for or against the application of heliox in children treated for critical asthma. (Conditional recommendation, very low certainty of evidence) 11. We suggest the use of a dedicated protocol or pathway for managing children treated for critical asthma. (Conditional recommendation, low certainty of evidence).

Invasive Respiratory Support in Critical Pediatric Asthma

In the United States and Canada, severe asthma requiring mechanical ventilation has declined over the past decade reflecting a rise in noninvasive therapies. When aggressive noninvasive therapies fail, endotracheal intubation and mechanical ventilation are lifesaving and should be planned for in advance. As speed is important, the most experienced practitioner should intubate and rapid correction of hypercarbia and respiratory acidosis should be avoided. An elevated minute ventilation may cause pulmonary hyperinflation leading to air-leak syndrome and/or hemodynamic instability. Patients with severe air flow obstruction in asthma typically have near-normal respiratory system compliance. Therefore, an increase in plateau pressure (Pplat) usually reflects dynamic hyperinflation. A suggested upper limit for Pplat is 25-30 cm H2O. Intrinsic PEEP (PEEPi) is measured with an expiratory hold and is valuable in that PEEP set on the ventilator can be lower than PEEPi. A reasonable ventilation strategy involving low ventilator rates and PEEP without quick correction of blood gases should be adopted. Alternative modalities to conventional mechanical ventilation are limited and unless very experienced with high-frequency oscillatory ventilation, the risk likely outweighs benefit. Heliox may be beneficial but cannot be delivered by every ventilator and this varies by manufacturer. Inhaled anesthetics are direct bronchodilators and likely beneficial but as no conventional ICU ventilator can deliver them, close cooperation with Anesthesiology is needed. Extracorporeal membrane oxygenation (ECMO) is a rescue therapy that is particularly useful in cases of severe air-leak syndrome. As with mechanical ventilation, ECMO does not reverse the asthma disease process but allows support of the patient until there is improvement with other therapies. Most children who die experience cardiac arrest prior to hospitalization. Otherwise, most mechanically ventilated children survive to hospital discharge but there is a suggestion of additional mortality from asthma in the following decade.

Treating acute severe asthma attacks in children: using aminophylline

Aminophylline does have a role in treating severe asthma attacks in children with asthma. Clinicians just need to be aware of the toxic side-effects of the drug and manage the drug carefully. https://bit.ly/3o7IJV1.

Terbutaline and aminophylline as second-line therapies for status asthmaticus in the pediatric intensive care unit

OBJECTIVE

Asthma is the most common chronic disease of childhood. Although asthma admissions to the pediatric intensive care unit (PICU) are increasing, there are no evidence-based guidelines on preferred escalation of therapies for patients with status asthmaticus who fail to respond to inhaled bronchodilators and systemic corticosteroids. The purpose of this study was to assess outcomes of PICU patients receiving aminophylline versus terbutaline as second-tier therapies for status asthmaticus.

DESIGN

Retrospective cohort study using Pediatric Health Information System from 2016-2019.

SETTING

Fifty-three tertiary children's hospitals.

SUBJECTS

Children aged 2 to 18 years admitted to the PICU in children's hospitals contributing data to the Pediatric Health Information System with a primary diagnosis of status asthmaticus.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 11 133 pediatric patients treated for status asthmaticus in the PICU during the study period, 1144 received either terbutaline or aminophylline. There was no difference in intubation and mechanical ventilation between patients who received aminophylline and those who received terbutaline. However, in African American patients, those who received terbutaline had a significantly higher odds of intubation and mechanical ventilation compared to those who received aminophylline (OR, 12.41; 95%CI, 1.61,95).

CONCLUSIONS

The use of aminophylline is associated with lower odds of intubation and mechanical ventilation in African American patients with status asthmaticus as compared to terbutaline.

Extracorporeal and advanced therapies for progressive refractory near-fatal acute severe asthma in children

Asthma is the most common chronic illness and is one of the most common medical emergencies in children. Progressive refractory near-fatal asthma requiring intubation and mechanical ventilation can lead to death. Extracorporeal membrane oxygenation (ECMO) can provide adequate gas exchange during acute respiratory failure although data on outcomes in children requiring ECMO support for status asthmaticus is sparse with one study reporting survival rates of nearly 85% with asthma being one of the best outcome subsets for patients with refractory respiratory failure requiring ECMO support. We describe the current literature on the use of ECMO and other advanced extracorporeal therapies available for children with acute severe asthma. We also review other advanced invasive and noninvasive therapies in acute severe asthma both before and while on ECMO support.

A Contemporary Approach to the Treatment of Perioperative Bronchospasm

The incidence of asthma is increasing, and the ageing of the United States population is leading to an increase in the prevalence of patients living with chronic obstructive pulmonary disease. This has led to an increased need to manage bronchospasm in the perioperative period. Very effective methods to treat bronchospasm like intravenous dexmedetomidine, lidocaine, magnesium, ketamine and steroids as well as inhalational sevoflurane are available but are currently underused. Inhaled beta-2 agonists like albuterol are instead often relied upon as the sole therapeutic agent - often with limited response. Just like with pain management, the successful treatment of perioperative bronchospasm requires a multimodal approach. The diagnosis of intraoperative bronchospasm must be rapid, and the treatment must be effective to prevent the dreaded "dynamic hyperinflation syndrome". This article reviews the diagnosis of bronchospasm and the contemporary treatment methods that should be employed to prevent bronchospasm-related morbidity and mortality during the perioperative period.

The Differences in Acute Management of Asthma in Adults and Children

Acute asthma or wheeze is a common presentation to emergency services for both adults and children. Although there are phenotypic differences between asthma syndromes, the management of acute symptoms follow similar lines. This article looks at the similarities and differences in approaches for children and adults. Some of these may be age dependent, such as the physiological parameters used to define the severity of the attack or the use of age appropriate inhaler devices. Other differences may reflect the availability of evidence. In other areas there is conflicting evidence between adult and pediatric studies such as a temporary increase in dose of inhaled corticosteroids during an acute attack. Overall there are more similarities than differences.

Outcomes of paediatric critical care asthma patients

AIM

The aim of this study was to characterise patients with asthma admitted to an Australian paediatric intensive care unit (PICU).

METHODS

This was a retrospective review of patients with asthma admitted to a university-affiliated, 23-bed, tertiary PICU between January 2000 and December 2011, with a subset of pharmacotherapy and biochemical data from patients admitted between July 2007 and December 2011.

RESULTS

A total of 589 admissions (501 patients) with asthma over 12 years constituted 4.4% of all PICU admissions. Three patients died (0.6%). Non-invasive ventilation (NIV) was used in 104 (17.7%) admissions, and 41 (7%) were invasively ventilated. On 12 (2%) occasions, patients received both NIV and invasive ventilation. Over 12 years, there was a significant trend to increased use of NIV, 11-39% (P < 0.0001), and invasive ventilation, 6-14% (P < 0.001). All received steroids and nebulised β2-agonists. A total of 92% received intravenous (IV) β2-agonists, 65% of these for less than 12 h. PICU and hospital stay were proportional to the duration of IV β2-agonist infusion (P < 0.0001). A total of 47.1% received IV magnesium sulphate, increasing from 19 to 75% (P < 0.001). The majority (48%) were transferred directly to PICU from other hospitals. Median PICU stay was 1.04 days (0.72-1.63); hospital stay was 3.16 days (2.29-4.71), and both were unchanged.

CONCLUSIONS

Intensive care length of stay (LOS) was unchanged over 12 years. Both invasive and NIV and IV magnesium sulphate use increased. LOS was directly related to the duration of IV β2-agonist. Asthma patients admitted to PICU typically have a brief stay and have a fairly predictable course. Prospective studies could explore the contribution of IV agents and the role of NIV.

Efficacy and side effects of intravenous theophylline in acute asthma: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Theophylline has been used for decades to treat both acute and chronic asthma. Despite its longevity in the practitioner's formulary, no detailed meta-analysis has been performed to determine the conditions, including concomitant medications, under which theophylline should be used for acute exacerbations of asthma. We aimed to quantify the usefulness and side effects of theophylline with or without ethylene diamine (aminophylline) in acute asthma, with particular emphasis on patient subgroups, such as children, adults, and concomitant medications.

METHODS

We searched PubMed, EMBASE, The Cochrane Library, ClinicalTrials.gov, and the WHO Clinical Trials Registry for randomized, controlled clinical trials. We planned a priori subgroup analyses by time post-medication, concomitant medication, control type, and age.

RESULTS

We included 52 study arms from 42 individual trials. Of these, 29 study arms included an active control, such as adrenaline, beta-2 agonists, or leukotriene receptor antagonists, and 23 study arms compared theophylline (with or without ethylene diamine) with placebo or no drug. Theophylline significantly reduced heart rate when compared with active control (p=0.01) and overall duration of stay (p=0.002), but beta-2 agonists were superior to theophylline at improving forced expiratory volume in one second (FEV1) (p=0.002). Theophylline was not significantly different from other drugs in its effects on respiratory rate, forced vital capacity (FVC), peak expiratory flow rate, admission rate, use of rescue medication, oxygen saturation, or symptom score. Closer examination of the data revealed that the medications given in addition to theophylline or control significantly changed the effectiveness of theophylline (subgroup difference: p<0.00001).

CONCLUSION

Given the low cost of theophylline, and its similar efficacy and rate of side effects compared with other drugs, we suggest that theophylline, when given with bronchodilators with or without steroids, is a cost-effective and safe choice for acute asthma exacerbations.

Optimizing the Dosing of Intravenous Theophylline in Acute Severe Asthma in Children

Optimizing the management of children presenting with acute severe asthma is of utmost importance to minimize hospital stays, morbidity, and mortality. Intravenous medications, including theophyllines, are used as second-line treatments for children experiencing a life-threatening exacerbation. For intravenous theophylline (aminophylline), guidelines and formularies recommend a target therapeutic range between 10 and 20 mg/l, with the commonest regimen being a loading dose of 5 mg/kg followed by an infusion calculated by age and weight. This review assesses the evidence underpinning these recommendations, highlighting the shortcomings in our understanding of the association between serum concentrations achieved, dose given, and clinical improvement experienced. To close the knowledge gap and improve outcomes for children presenting with acute severe asthma, we propose a series of research strategies to improve the assessment of illness severity, ascertain the optimal dose to maximize benefit and minimize risk, prospectively collect adverse events, and to better understand the inter-individual variation in responses to treatments.

Aminophylline Dosage In Asthma Exacerbations in Children: A Systematic Review

BACKGROUND

Adequate asthma treatment of childhood exacerbations with IV aminophylline depends on appropriate dosage. Recommendations to aim for a target therapeutic range may be inappropriate as serum concentrations correlate poorly with clinical improvement. This review aims to evaluate the evidence for the optimum dosage strategy of intravenous aminophylline in children suffering an exacerbation of asthma.

METHODS

A systematic review comparing dosage regimens of intravenous aminophylline in children suffering an exacerbation of asthma. Primary outcomes were time until resolution of symptoms, mortality and need for mechanical ventilation. Secondary outcomes were date until discharge criteria are met, actual discharge and adverse effects.

DATA SOURCES

CENTRAL, CINAHL, MEDLINE and Web of Science. Search performed in March 2016.

ELIGIBILITY CRITERIA

Studies using intravenous aminophylline in children with an acute exacerbation of asthma which reported the dosage and clinical outcomes.

FINDINGS

14 RCTs were included. There is a poor relationship between the dosage administered to children and symptom resolution, length of stay or need for mechanical ventilation. This study is limited due to its use of indirect evidence.

CONCLUSION

The currently recommended dosage regimens may not represent the optimum safety and efficacy of intravenous aminophylline. There is a need to develop the evidence base correlating dosage with patient centered clinical outcomes, to improve prescribing practices.

Contemporary treatment of children with critical and near-fatal asthma

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.

The Evidence for Intravenous Theophylline Levels between 10-20mg/L in Children Suffering an Acute Exacerbation of Asthma: A Systematic Review

Background

Intravenous theophyllines are a second line treatment for children suffering an acute exacerbation of asthma. Various guidelines and formularies recommend aiming for serum theophylline levels between 10-20mg/l. This review aims to assess the evidence underpinning this recommendation.

Methods

A systematic review comparing outcomes of children who achieved serum theophylline concentrations between 10-20mg/l with those who did not. Primary outcomes were time until resolution of symptoms, mortality and need for mechanical ventilation. Secondary outcomes were date until discharge criteria are met, actual discharge, adverse effects and FEV1.

Data sources

MEDLINE, CINAHL, CENTRAL and Web of Science. Search performed in October 2015.

Eligibility criteria

Interventional or observational studies utilizing intravenous theophyllines for an acute exacerbation of asthma in children where serum theophylline levels and clinical outcomes were measured.

Findings

10 RCTs and 2 observational studies were included. Children with serum levels between 10-20mg/l did not have a reduction in duration of symptoms, length of hospital stay or need for mechanical ventilation or better spirometric results compared with levels <10mg/l. Levels above 20mg/l are not associated with higher rates of adverse effects. This study is limited due to heterogeneity in the way theophylline levels were reported and poor surveillance of adverse effects across studies.

Conclusion

Dosing strategies aiming for levels between 10-20mg/l are not associated with better outcomes. Clinicians should rely on clinical outcomes and not serum levels when using intravenous theophyllines in children suffering an acute exacerbation of asthma.

Acute severe asthma

Acute exacerbations of asthma are very common reasons for a presentation to emergency departments. This paper focuses on defining the high-risk group, consideration of the concept of phenotypes of acute asthma, the assessment of severe and life-threatening exacerbations and an emphasis on the management of the more severe end of the exacerbation severity. A number of evidence-based guidelines exist throughout the world and are all slightly different. This reflects the poor evidence base for some of those recommendations. Thus, a large variation of treatment drugs, doses and regimen are used and clearly not standardised. This paper aims to present a summary of the best evidence and discuss some of these controversies. The most important aspect of treating an exacerbation of acute asthma is to review regularly and assess response to treatment. Severe and life-threatening episodes should be treated with early use of intravenous treatment in a stepwise manner following the local guidelines. Non-invasive ventilation and high flow nasal cannulae delivery of oxygen in the emergency department are evolving modalities, but evidence for their use is currently limited.

Pharmacotherapy of critical asthma syndrome: current and emerging therapies

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient's response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

The acute management of asthma

Patients presenting to the emergency department (ED) or clinic with acute exacerbation of asthma (AEA) can be very challenging varying in both severity and response to therapy. High-dose, frequent or continuous nebulized short-acting beta2 agonist (SABA) therapy that can be combined with a short-acting muscarinic antagonist (SAMA) is the backbone of treatment. When patients do not rapidly clinically respond to SABA/SAMA inhalation, the early use of oral or parenteral corticosteroids should be considered and has been shown to impact the immediate need for ICU admission or even the need for hospital admission. Adjunctive therapies such as the use of intravenous magnesium and helium/oxygen combination gas for inhalation and for driving a nebulizer to deliver a SABA and or SAMA should be considered and are best used early in the treatment plan if they are likely to impact the patients' clinical course. The use of other agents such as theophylline, leukotriene modifiers, inhaled corticosteroids, long-acting beta2 agonist, and long-acting muscarinic antagonist currently does not play a major role in the immediate treatment of AEA in the clinic or the ED but is an important therapeutic option for physicians to be aware of and to consider initiating at the time of discharge from clinic, hospital, or ED to reduce later clinical worsening and readmission to the ED and hospital. A comprehensive summary is provided of the currently available respiratory pharmaceuticals approved for asthma and other airway syndromes. Clinicians must be prepared to use the entire spectrum of medications available for the treatment of acute asthma exacerbations and the agents that should be initiated to prevent worsening or additional exacerbations. They need to be familiar with the major potential drug toxicities associated with their use.

Inhaled anticholinergics and short-acting beta(2)-agonists versus short-acting beta2-agonists alone for children with acute asthma in hospital

BACKGROUND

Inhaled anticholinergics given in addition to β2-agonists are effective in reducing hospital admissions in children presenting to the emergency department with a moderate to severe asthma exacerbation. It seems logical to assume a similar beneficial effect in children hospitalised for an acute asthma exacerbation.

OBJECTIVES

To assess the efficacy and safety of anticholinergics added to β2-agonists as inhaled or nebulised therapy in children hospitalised for an acute asthma exacerbation. To investigate the characteristics of patients or therapy, if any, that would influence the magnitude of response attributable to the addition of anticholinergics.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register of trials (CAGR), which is derived through systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED and PsycINFO and through handsearching of respiratory journals and meeting abstracts. The search is current to November 2013.

SELECTION CRITERIA

Randomised trials comparing the combination of inhaled or nebulised anticholinergics and short-acting β2-agonists versus short-acting β2-agonists alone in children one to 18 years of age hospitalised for an acute asthma exacerbation were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of trials and extracted data; disagreement was resolved by consensus or with the input of a third review author, when needed. Primary outcomes were duration of hospital stay and serious adverse events. Secondary outcomes included admission and duration of stay in the intensive care unit (ICU), ventilation assistance, time to short-acting β2-agonists spaced at four hours or longer, supplemental asthma therapy, duration of supplemental oxygen, change from baseline in asthma severity, relapse after discharge, adverse health effects and withdrawals.

MAIN RESULTS

Seven randomised trials were included, four of which reported usable data on 472 children with asthma one to 18 years of age who were admitted to paediatric wards. No trials included patients admitted to the ICU. The anticholinergic used, ipratropium bromide 250 μg, was given every one to eight hours over a period from four hours to the entire length of the hospital stay. Two of four trials (50%) contributing data were deemed of high methodological quality. The addition of anticholinergics to β2-agonists showed no evidence of effect on the duration of hospital admission (mean difference (MD) -0.28 hours, 95% confidence interval (CI) -5.07 to 4.52, 3 studies, 327 participants, moderate quality evidence) and no serious or non-serious adverse events were reported in any included trials. As a result of the similarity of trials, we could not explore the influence of age, admission site, intensity of anticholinergic treatment and co-interventions on primary outcomes. No statistically significant group difference was noted in other secondary outcomes, including the need for supplemental asthma therapy, time to short-acting β2-agonists spaced at four hours or longer, asthma clinical scores, lung function and overall withdrawals for any reason.

AUTHORS' CONCLUSIONS

In children hospitalised for an acute asthma exacerbation, no evidence of benefit for length of hospital stay and other markers of response to therapy was noted when nebulised anticholinergics were added to short-acting β2-agonists. No adverse health effects were reported, yet the small number of trials combined with inadequate reporting prevent firm reassurance regarding the safety of anticholinergics. In the absence of trials conducted in ICUs, no conclusion can be drawn regarding children with impending respiratory failure. These findings support current national and international recommendations indicating that healthcare practitioners should refrain from using anticholinergics in children hospitalised for acute asthma.

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.

Magnesium sulphate in acute severe asthma in children (MAGNETIC): a randomised, placebo-controlled trial

BACKGROUND

Little evidence is available for the effect of nebulised magnesium sulphate (MgSO(4)) in acute asthma in children. We assessed the effect of MgSO(4) treatment in children with severe acute asthma.

METHODS

In this randomised placebo-controlled, multi-centre, parallel trial, we enrolled children (aged 2-16 years) with severe acute asthma who did not respond to standard inhaled treatment from 30 hospitals in the UK. Children were randomly allocated (1:1) to receive nebulised salbutamol and ipratropium bromide with either 2·5 mL of isotonic MgSO(4) (250 mmol/L; 151 mg per dose; MgSO(4) group) or 2·5 mL of isotonic saline (placebo group) on three occasions at 20-min intervals. Randomisation was done with a computer-generated randomisation sequence, with random block sizes of two to four. Both patients and researchers were masked to treatment allocation. The primary outcome measure was the Yung Asthma Severity Score (ASS) at 60 min post-randomisation. We used a statistical significance level of p<0·05 for a between-group difference, but regarded a between-group difference in ASS of 0·5 as the minimal clinically significant treatment effect. Analysis was done by intention to treat. This trial is registered with controlled-trials.com, number ISRCTN81456894.

FINDINGS

Between Jan 3, 2009, and March 20, 2011, we recruited and randomly assigned 508 children to treatment: 252 to MgSO(4) and 256 to placebo. Mean ASS at 60 min was lower in the MgSO(4) group (4·72 [SD 1·37]) than it was in the placebo group (4·95 [SD 1·40]; adjusted difference -0·25, 95% CI -0·48 to -0·02; p=0·03). This difference, however, was not clinically significant. The clinical effect was larger in children with more severe asthma exacerbation (p=0·03) and those with symptoms present for less than 6 h (p=0·049). We detected no difference in the occurrence of adverse events between groups.

INTERPRETATION

Overall, nebulised isotonic MgSO(4), given as an adjuvant to standard treatment, did not show a clinically significant improvement in mean ASS in children with acute severe asthma. However, the greatest clinical response was seen in children with more severe attacks (SaO(2)<92%) at presentation and those with preceding symptoms lasting less than 6 h.

FUNDING

National Institute for Health Research Health Technology Assessment Programme.

Aminophylline infusion for status asthmaticus in the pediatric critical care unit setting is independently associated with increased length of stay and time for symptom improvement

INTRODUCTION

The role of aminophylline in the treatment of severe acute asthma in the pediatric critical care unit (PCCU) is not clear. We sought to examine the association of aminophylline treatment with PCCU length of stay and time to symptom improvement.

MATERIAL AND METHODS

Patients with severe acute asthma who were admitted to our PCCU and received aminophylline infusion were retrospectively compared with similar patients who did not receive aminophylline. The primary outcome measure was functional length of stay (i.e. time to which patients could be transferred to a general pediatric ward bed). A secondary outcome was time to symptom improvement.

RESULTS

Adjusted functional length of stay was longer for subjects who received aminophylline (n = 49) than for the patients who did not (n = 47) (hazard ratio 0.396, p < 0.001), as well as the time for symptom improvement (hazard ratio 0.359, p < 0.001). In the group of subjects receiving aminophylline, those with a serum theophylline level ≥ 10 mcg/ml (therapeutic) (n = 31) had longer functional length of stay (hazard ratio 0.457, p = 0.0225) and time to symptom improvement (hazard ratio 0.403, p = 0.0085) than those with levels < 10 mcg/ml (sub-therapeutic) (n = 18).

CONCLUSIONS

The addition of aminophylline to therapy with corticosteroids and inhaled β-agonists was associated with statistically and clinically significant increases in functional length of stay and time to symptom improvement in the PCCU. This potential morbidity supports the National Asthma Education and Prevention Program guideline proscribing aminophylline use in acute asthma.

Inhaled and intravenous treatment in acute severe and life-threatening asthma

Management of life-threatening acute severe asthma in children and adults may require anaesthetic and intensive care. The inhaled route for drug delivery is not appropriate when only small respiratory gas volumes are shifted; the i.v. route may be associated with greater side-effects. Magnesium sulphate i.v. has a place in acute asthma management because it is a mild bronchodilator, and has a stabilizing effect on the atria which may attenuate tachycardia occurring after inhaled and i.v. salbutamol. If intubation and ventilation are required, a reduction in bronchoconstriction by any means before and during these procedures should reduce morbidity. This narrative review aims to show strengths and weakness of the evidence, present controversies, and forward opinions of the author. The review contains a practical guide to the setting up, use and efficiency of nebulizers, metered dose inhalers, and spacers (chambers). It also presents a commonsense approach to the management of severe asthmatics in whom delay in bronchodilatation would cause clinical deterioration. When self-inhaled agents have had no effect, i.v. drugs may help avoid intubation and ventilation. The review includes suggestions for the use of inhaled anaesthetics, anaesthetic induction, and brief notes on subsequent ventilation of the lungs.

Ketamine for management of acute exacerbations of asthma in children

BACKGROUND

Asthma is the most common chronic disease in children, and children with asthma frequently visit the paediatric emergency departments with acute exacerbations. Some of these children fail to respond to standard therapy (aerosol beta(2)-agonist with or without aerosol anticholinergic and oral or parenteral corticosteroids) for acute asthma leading to prolonged emergency department stay, hospitalisation, morbidity (e.g. barotrauma, intubation) and death, albeit rarely. Ketamine may relieve bronchospasm and is a potentially promising therapy for children with acute asthma who fail to respond to standard treatment.

OBJECTIVES

To evaluate the efficacy of ketamine compared to placebo, no intervention or standard care for management of severe acute asthma in children who had not responded to standard therapy.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register of trials (CAGR) and ClinicalTrials.gov. We reviewed reference lists of all primary studies and review articles for additional references. We contacted authors of identified trials and asked them to identify other published and unpublished studies. The latest search was in July 2012.

SELECTION CRITERIA

Randomised controlled trials comparing ketamine to placebo or standard care in children (up to 18 years of age) presenting with an acute asthma exacerbation who had not responded to standard therapy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies. The data were extracted in pre-defined proforma and were analysed independently by two review authors. The data analysis was performed using Review Manager 5.1.

MAIN RESULTS

A single study enrolling 68 non-intubated children was found eligible for inclusion in review. The study had low or unclear risk of bias. It demonstrated no significant difference in respiratory rate, oxygen saturation, hospital admission rate (odds ratio (OR) 0.77; 95% confidence interval (CI) 0.23 to 2.58) and need for mechanical ventilation between ketamine (0.2 mg/kg intravenous bolus over one to two minutes, followed by a 0.5 mg/kg per hour continuous infusion for two hours) and placebo group. There were no significant side effects of ketamine in the study. There was also no difference in need for other adjuvant therapy (OR 2.19; 95% CI 0.19 to 25.40) and in Pulmonary Index Score (mean difference (MD) -0.40; 95% CI -1.21 to 0.41) between the groups.

AUTHORS' CONCLUSIONS

The single study on non-intubated children with severe acute asthma did not show significant benefit and does not support the case studies and observational reports showing benefits of ketamine in both non-ventilated and ventilated children. There were no significant side effects of ketamine. We could not find any trials on ventilated children. To prove that ketamine is an effective treatment for acute asthma in children, there is need for sufficiently powered randomised trials of high methodological quality with objective outcome measures of clinical importance. Future trials should also explore different doses of ketamine and its role in children needing ventilation because of severe acute asthma.

Fatal and near-fatal asthma in children: the critical care perspective

OBJECTIVE

To characterize the clinical course, therapies, and outcomes of children with fatal and near-fatal asthma admitted to pediatric intensive care units (PICUs).

STUDY DESIGN

This was a retrospective chart abstraction across the 8 tertiary care PICUs of the Collaborative Pediatric Critical Care Research Network (CPCCRN). Inclusion criteria were children (aged 1-18 years) admitted between 2005 and 2009 (inclusive) for asthma who received ventilation (near-fatal) or died (fatal). Data collected included medications, ventilator strategies, concomitant therapies, demographic information, and risk variables.

RESULTS

Of the 261 eligible children, 33 (13%) had no previous history of asthma, 218 (84%) survived with no known complications, and 32 (12%) had complications. Eleven (4%) died, 10 of whom had experienced cardiac arrest before admission. Patients intubated outside the PICU had a shorter duration of ventilation (median, 25 hours vs 84 hours; P < .001). African-Americans were disproportionately represented among the intubated children and had a shorter duration of intubation. Barotrauma occurred in 15 children (6%) before admission. Pharmacologic therapy was highly variable, with similar outcomes.

CONCLUSION

Of the children ventilated in the CPCCRN PICUs, 96% survived to hospital discharge. Most of the children who died experienced cardiac arrest before admission. Intubation outside the PICU was correlated with shorter duration of ventilation. Complications of barotrauma and neuromyopathy were uncommon. Practice patterns varied widely among the CPCCRN sites.

Pharmacology and therapeutics of bronchodilators

Bronchodilators are central in the treatment of of airways disorders. They are the mainstay of the current management of chronic obstructive pulmonary disease (COPD) and are critical in the symptomatic management of asthma, although controversies around the use of these drugs remain. Bronchodilators work through their direct relaxation effect on airway smooth muscle cells. at present, three major classes of bronchodilators, β(2)-adrenoceptor (AR) agonists, muscarinic receptor antagonists, and xanthines are available and can be used individually or in combination. The use of the inhaled route is currently preferred to minimize systemic effects. Fast- and short-acting agents are best used for rescue of symptoms, whereas long-acting agents are best used for maintenance therapy. It has proven difficult to discover novel classes of bronchodilator drugs, although potential new targets are emerging. Consequently, the logical approach has been to improve the existing bronchodilators, although several novel broncholytic classes are under development. An important step in simplifying asthma and COPD management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Therefore, the incorporation of once-daily dose administration is an important strategy to improve adherence. Several once-daily β(2)-AR agonists or ultra-long-acting β(2)-AR-agonists (LABAs), such as indacaterol, olodaterol, and vilanterol, are already in the market or under development for the treatment of COPD and asthma, but current recommendations suggest the use of LABAs only in combination with an inhaled corticosteroid. In addition, some new potentially long-acting antimuscarinic agents, such as glycopyrronium bromide (NVA-237), aclidinium bromide, and umeclidinium bromide (GSK573719), are under development, as well as combinations of several classes of long-acting bronchodilator drugs, in an attempt to simplify treatment regimens as much as possible. This review will describe the pharmacology and therapeutics of old, new, and emerging classes of bronchodilator.

Progress in the management of childhood asthma

Asthma has become the most common chronic disease in childhood. Significant advances in epidemiological research as well as in therapy of pediatric asthma have been made over the past 2 decades. In this review, we look at certain aspects therapy of childhood asthma, both in the past and present. Literature review on allergen avoidance (including mites, cockroach and cat), intensive therapy with β(2)-agonists in acute asthma (administering via continuous nebulization and intravenous routes), a revisit of theophylline use and its action, the use of inhaled corticosteroids in various phases of childhood asthma and sublingual immunotherapy in asthma are examined. Recent facts and dilemmas of these treatments are identified along with expression of our opinions, particularly on points of childhood asthma in the Asia-Pacific, are made in this review.

Audit of acute asthma management at the Paediatric Emergency Department at Wad Madani Children's Hospital, Sudan

This audit of hospital care of acute wheeze and asthma aimed to assess the degree of adherence of the acute care of the asthma patients to the published international guidelines. Information was collected in six key areas: patient demographics; initial asthma severity assessment; in-hospital treatment; asthma prophylaxis; asthma education and emergency planning; and follow-up arrangements. The area of initial asthma severity assessment showed defciencies in the clinical measures currently used to verify case severity. In- hospital treatment on the other hand was consistent with recommendations in the use of the inhaled β-2 agonist salbutamol as bronchodilator, the discrete use of aminophylline and the small number of patients ordered chest X-ray. However, the treatment was incoherent with recommendations in the delivery method used for inhaled bronchodilator in relation to the age group of treated patients, absence of ipratropium bromide as a bronchodilator in the management and the large use of antibiotics. Assessment of the areas of asthma prophylaxis, asthma education and emergency- planning and follow-up arrangements illustrated that little efforts were made to assure safe discharge, although these measures have been shown to reduce morbidity after the exacerbation and reduce relapse rates and signifcantly reduce hospitalizations, unscheduled acute visits, missed work days, as well as improving quality of life. This audit emphasizes the need for the adoption of a management protocol for acute asthma care in the emergency department based on published international guidelines and the assurance of its implementation, monitoring and evaluation using the right tools to improve patient care.

Severe Asthma

Despite vast improvements in the care of children with asthma over the past decades, asthma remains a common cause of admission to pediatric intensive care units. During the 1990s asthma prevalence and hospital admissions increased in the United States and worldwide. The increase occurred in both males and females and across all ethnic groups. However, the largest increases occurred in children of low socioeconomic status living in urban settings. Recent asthma statistics should be interpreted with consideration of changes made in the method for reporting asthma prevalence (Fig. 23-1). From 1980 to 1996, the National Health Interview Survey (NHIS) conducted by the CDC measured pediatric asthma prevalence as the percentage of children with asthma in the past 12 months. Since 1997, asthma prevalence estimates have been defined as: having received an asthma diagnosis, currently having the disease at the time of the interview, and experiencing an attack in the past year. The more specific definition may have led to a reduction in the number of children reported to have asthma.

Management of severe asthma exacerbation in children

BACKGROUND

Asthma is a common disease in children and acute severe asthma exacerbation can be life-threatening. This article aims to review recent advances in understanding of risk factors, pathophysiology, diagnosis and treatment of severe asthma exacerbation in children.

DATA SOURCES

Articles concerning severe asthma exacerbation in children were retrieved from PubMed. Literatures were searched with MeSH words "asthma", "children", "severe asthma exacerbation" and relevant cross references.

RESULTS

Severe asthma exacerbation in children requires aggressive treatments with β2-agonists, anticholinergics, and corticosteroids. Early initiation of inhaled β-agonists and systemic use of steroids are recommended. Other agents such as magnesium and aminophylline have some therapeutic benefits. When intubation and mechanical ventilation are needed, low tidal volume, controlled hypoventilation with lower-than-traditional respiratory rates and permissive hypercapnia can be applied.

CONCLUSIONS

Researchers should continue to detect the risk factors, pathophysiology, diagnosis and treatment of severe asthma exacerbation in children. More studies especially randomized controlled trials are required to evaluate the efficacy and safety of standard and new therapies.

Pharmacologic approaches to life-threatening asthma

Following a peak in asthma mortality in the late 1980s and early 1990s, we have been fortunate to see a substantial decrease in asthma deaths in recent years. Although most asthma deaths occur outside the hospital, near-fatal events are commonplace, with anywhere from 2-20% of patients with acute asthma admitted to intensive care, and 2-4% intubated for respiratory failure. Standard therapies for acute severe and near-fatal asthma include administration of systemic corticosteroids, and frequent or continuous inhaled beta agonists. Controversy remains regarding the optimal therapy of those who fail to respond to these initial treatments, those who remain at risk of acute respiratory failure, and patients requiring mechanical ventilation. There remain significant gaps in our knowledge regarding relative benefits of intravenous versus oral corticosteroids, intermittent versus continuous beta agonists, and the role of various adjunctive treatments including intravenous magnesium, systemic beta agonists, aminophylline, and helium-oxygen mixtures. Using models and radiolabeled aerosols, there is a greater understanding regarding effective administration of inhaled beta-agonists in ventilated patients. There is limited available evidence for treatment of near-fatal asthma, a fact reflected by the significant variability in asthma critical care practice. Much of the data guiding treatment in this setting has been generalized from studies of acute asthma in the ED and from general populations of hospitalized patients with acute asthma. This review will focus on pharmacologic approaches to life-threatening asthma by reviewing current guideline recommendations, reviewing the scientific basis of the guidelines, and highlighting gaps in our knowledge in treatment of refractory acute or near-fatal asthma.

Self assessment exercises in Intensive Care Medicine

Intensive Care Medicine (ICM) is no longer the exclusive preserve of anaesthetists as both emergency medicine and general medicine trainees now also train in this increasingly important speciality. This edition of the JRAMC self assessment question series serves to cover some of the current 'hot topics' in ICM and enables readers with experience of ICM to test their knowledge as well as educating junior trainees in relevant subjects that they may be unfamiliar with. Similarly, the Focus On .... series of papers elsewhere in this journal demonstrate the increasing importance of ICM in the deployed Field Hospital setting.

Aminophylline for treating asthma and chronic obstructive pulmonary disease

Aminophylline is a complex of theophylline and ethylenediamine. Its main pharmacological action is relaxation of bronchial smooth muscle. Two meta-analyses examining the efficacy of aminophylline in acute asthma attacks in children and in adults have been reported by the Cochrane Collaboration. In the meta-analysis reporting results from studies in children, it was concluded that aminophylline does not add any benefit to standard care. Yet one study, which has the largest patient population, reports that aminophylline improves lung functions within 6-8 h and reduces the risk of intubation. The meta-analysis examining adult studies revealed that there is no outstanding difference between aminophylline and standard therapy in the management of adult acute asthma. In conclusion, aminophylline may be an alternative to intravenous infusion of beta-agonists, heliox or magnesium sulfate administration in children in whom respiratory fatigue begins to develop and intensive-care unit admission and mechanical ventilation seems to be the next treatment in line. However, in adults, it is not recommended for use in the treatment of acute asthma owing to its possible adverse effects.

Emergency presentation and management of acute severe asthma in children

Acute severe asthma is one of the most common medical emergency situations in childhood, and physicians caring for acutely ill children are regularly faced with this condition. In this article we present a summary of the pathophysiology as well as guidelines for the treatment of acute severe asthma in children. The cornerstones of the management of acute asthma in children are rapid administration of oxygen, inhalations with bronchodilators and systemic corticosteroids. Inhaled bronchodilators may include selective b2-agonists, adrenaline and anticholinergics. Additional treatment in selected cases may involve intravenous administration of theophylline, b2-agonists and magnesium sulphate. Both non-invasive and invasive ventilation may be options when medical treatment fails to prevent respiratory failure. It is important that relevant treatment algorithms exist, applicable to all levels of the treatment chain and reflecting local considerations and circumstances.

Effect of gender on theophylline clearance in the asthmatic acute phase in Japanese pediatric patients

The effect of gender on theophylline clearance was investigated retrospectively in 96 Japanese pediatric patients (63 males and 33 females) ranging in age from 0.5 to 8 years and in weight from 6.3 to 36.8 kg. All patients received intravenous constant-rate infusion of aminophylline in the asthmatic acute phase. The theophylline clearances in males and females were 56.2+/-15.4 and 50.1+/-14.2 ml/h/kg for ages 0.5-<2 years, 58.7+/-18.8 and 48.3+/-6.5 ml/h/kg for ages 2-<4 years, and 65.7+/-12.0 and 52.1+/-16.8 ml/h/kg for ages 4-<9 years, respectively. At ages from 2 to 8 years, the theophylline clearance was 20% higher in males than in females (p<0.05). Our findings suggested that the initial dosage of theophylline should be adjusted according to the gender of pediatric patients and particularly in the case of infants.

Asthma in childhood

Management decisions for pediatric asthma (in patients younger than 12 years of age) based on extrapolation from available evidence in adolescents and adults (age 12 years and older) is common but rarely appropriate. This article addresses the disparity in response between the two age groups, presents the available pediatric evidence, and highlights the important areas in which further research is required. Evidence-based recommendations for acute and interval management of pediatric asthma are provided.

Beta2-adrenoceptor polymorphisms predict response to beta2-agonists in children with acute asthma

The aim of this study was to determine the influence of single nucleotide polymorphisms in the beta(2)-adrenoceptor gene, on the response to inhaled beta(2)-agonists in children with acute asthma. We hypothesised that children with polymorphisms that generate enhanced receptor downregulation in vitro, Gly16 and Gln27, would have a slower response to beta(2)-agonist therapy during acute asthma. One hundred and forty-eight children with acute asthma were recruited and genotyped for beta(2)Arg16Gly and beta(2)Gln27Glu. For Gln27Glu, individuals Gln27Gln took longest to stretch out to 1, 2 and 4 hourly beta(2)-agonists, followed by heterozygotes who were intermediate and Glu27Glu who responded most rapidly (1 hourly: 2.6 hr vs. 2.0 vs. 1.4, p = 0.02; 2 hourly: 10.6 hr vs. 10.7 vs. 6.8, p = 0.07; 4 hourly: 29.8 hr vs. 28.5 vs. 24.3, p = 0.30). The ability to prospectively identify children who respond less effectively to beta (2)-agonists during an acute asthma attack has the potential to allow the generation of genotype-specific treatment pathways.

Early administration of two intravenous bolus of aminophylline added to the standard treatment of children with acute asthma

OBJECTIVES

Evaluate the efficacy of adding two intravenous bolus of aminophylline to the standard treatment of acute asthma episode in children admitted to the pediatric emergency room (PER).

METHODS

Between March 2001 and February 2002, 60 children (2-5 years old), admitted to the PER at Hospital de Clínicas de Porto Alegre (Brazil), due to an episode of acute asthma, refractory to conventional therapy (an oral dose of steroids and at least three doses of inhaled albuterol, associated or not with oxygen) were enrolled in a randomized, double blind, placebo controlled clinical trial. The randomization was performed in blocks of 10 patients, who received a "bronchodilator solution" (either saline or aminophylline), in two doses: on arrival at the PER and again 6h later. The intervention group received aminophylline 5mg/kg/dose diluted in normal saline (NS) solution up to a 20 mL volume, while the placebo group received plain NS, both in an infusion rate of 1 cc/min. The main outcomes were total length of hospital stay, length of supplemental oxygen use, number of bronchodilator nebulizations and/or aerosol inhalations performed and patient destination. The groups were compared using the Students t-test, Mann-Whitney test and Chi-Square test, accepting p<0.05 as significant.

RESULTS

Comparing the main outcomes, we did not find differences between the placebo and aminophylline groups: 29.0+/-14.7 versus 26.2+/-13.4 beta-agonist nebulizations per patient (p=0.46); 2.4+/-10.6 versus 5.6+/-14.2 aerosol inhalations per patient (p=0.32); 24.7+/-30.0 versus 26.0+/-25.2h for oxygen supplement (p=0.86); 43.2+/-30.0 versus 43.6+/-23.7h for length of hospital stay (p=0.95). We also did not find differences between the two groups related to the blood pressure, heart rate, respiratory rate and oxygen saturation.

CONCLUSION

In children aged 2-5 years admitted to a PER with asthma, two intravenous doses of 5mg/kg of aminophylline given 6h apart did not change the length of stay in hospital, the number of nebulizations given or the duration of oxygen therapy required. We are unable to tell whether there would be benefit with higher doses of aminophylline designed to give levels in the usual therapeutic range.

Review of guidelines and the literature in the treatment of acute bronchospasm in asthma

Asthma is a common chronic condition that disproportionately affects persons younger than 45 years. Asthma exacerbations can be sudden and severe, requiring treatment in the emergency department or hospitalization. Children younger than 15 years are 2-4 times more likely to have asthma as the first-listed hospital discharge diagnosis compared with those in other age groups. An estimated 12.8 million missed school days and 24.5 million lost work days due to asthma occurred in 2003. Drugs used in the treatment of acute asthma include inhaled beta(2)-agonists, oral corticosteroids, and inhaled anticholinergics. Levalbuterol was evaluated in several recent trials for treatment of asthma in the emergency department, for its effect in improving pulmonary function and on hospitalization rate. Theophylline, intravenous beta(2)-agonists, intravenous magnesium sulfate, and inhaled anesthetics have not been proven useful in the emergency management of asthma. The effectiveness of inhalation devices is dependent on age, cooperation of the patient, and technique.

Use of theophylline in chronic obstructive pulmonary disease: examining the evidence

PURPOSE OF REVIEW

The role of theophylline in the management of chronic obstructive pulmonary disease remains controversial. This review was undertaken to determine the efficacy of theophylline in patients with stable disease.

RECENT FINDINGS

Twenty-two good quality randomized controlled trials were included in this systematic review. The review showed that theophylline significantly improved forced expiratory volume in 1 s and forced vital capacity (weighted mean difference 0.10 L; 95% confidence interval 0.04-0.16 and weighted mean difference 0.21 L; 95% confidence interval 0.10-0.31, respectively). V also improved with theophylline (weighted mean difference 195.27 mL/min; 95% confidence interval 112.71-277.83), as did Pa and Pa (weighted mean difference 1.45 mmHg; 95% confidence interval 0.26-2.65 and weighted mean difference -1.09 mmHg; 95% confidence interval -1.83 to -0.35, respectively). Patients preferred theophylline over placebo (relative risk 2.27; 95% confidence interval 1.26-4.11). Theophylline increased the risk of nausea, however, compared with placebo (relative risk 7.67; 95% confidence interval 1.47-39.94).

SUMMARY

This review has shown that oral theophylline plays an important role in the management of patients with stable chronic obstructive pulmonary disease by improving lung function, arterial blood gas tensions and ventilatory capacity. Patients also preferred treatment with theophylline when compared with placebo. The benefits of theophylline in stable chronic obstructive pulmonary disease, however, have to be weighed against the risk of adverse effects, particularly nausea.

A survey of consultant practice: intravenous salbutamol or aminophylline for acute severe childhood asthma and awareness of potential hypokalaemia

British Thoracic Society guidelines recommend intravenous salbutamol or aminophylline for acute severe asthma in children. In the survey reported here, 133 consultant paediatricians completed a questionnaire aimed at evaluating their choice of intravenous bronchodilator for acute severe asthma and their awareness of subsequent hypokalaemia. Of the non-Paediatric Intensive Care Unit (PICU) consultants who responded, 82%, including respiratory paediatricians, reported using aminophylline; in contrast, PICU consultants were significantly more likely to use salbutamol (p=<0.001). There was a lack of awareness that hypokalaemia occurs with aminophylline: 50% of the consultants suggested that hypokalaemia was rare or did not occur. Consultants using intravenous aminophylline were significantly less likely to recheck serum potassium levels than those using intravenous salbutamol (p=0.03). Based on the completed questionnaires, salbutamol infusions are rarely used outside the PICU, and the awareness of potential hypokalaemia following intravenous bronchodilator treatment is variable. It would appear, therefore, that standardised clinical practice is required in order to recognise and treat potential hypokalaemia.

Current management of status asthmaticus in the pediatric ICU

Status asthmaticus (SA) in the pediatric ICU (PICU) can progress to a life-threatening emergency. The goal of management is to improve hypoxemia, improve bronchoconstriction, and decrease airway edema through the administration of continuous nebulized beta2 adrenergic agonist with intermittent anticholinergics, corticosteroids, and oxygen. Adjunctive therapies, such as magnesium, methylxanthines, intravenous beta-agonists, heliox, and noninvasive ventilation should be considered in the child who fails to respond to initial therapies. The restoration of adequate pulmonary functions, resolution of airway obstruction, and avoidance of mechanical ventilation should guide management. This article reviews the pathophysiology, assessment, and management of the child who has SA in the PICU to provide the critical care nurse with current information to facilitate optimal care.

Theophylline metabolism in acute asthma with MxA-indicated viral infection

BACKGROUND

Although viral infection might alter theophylline metabolism in acute asthma, there are some difficulties in detecting infection due to various kinds of viruses in a clinical setting.

METHODS

To evaluate the usefulness of assessment of MxA protein in acute asthma exacerbated by viral infection, MxA protein expression in lymphocytes was assayed by flow cytometric analysis in whole peripheral blood in 21 children (aged 0-6 years) receiving continuous theophylline infusion for management of asthma attack. Serum theophylline levels were measured at 24 and 72 h after initiating theophylline infusion.

RESULTS

At the beginning of theophylline infusion, 11 children had increased expression of MxA protein, indicating viral infected states. After 24 h continuous infusion, there were no differences in theophylline levels between MxA-negative and MxA-positive groups. After 72 h infusion, the mean theophylline level of MxA-positive children was significantly higher than that of MxA-negative children (9.7 +/- 2.2 microg/mL vs 7.3 +/- 1.6 microg/mL). The ratio of theophylline clearance at 72 h to that at 24 h in the MxA-positive group was significantly lower than that of the MxA-negative group (1.1 +/- 0.2 vs 1.4 +/- 0.1).

CONCLUSIONS

Viral infection appeared to affect theophylline metabolism. Flow cytometric assay of lymphoid MxA protein expression in whole blood is an easy and useful method of evaluating viral infection in acute asthma exacerbation.

Regional variation in ICU care for pediatric patients with asthma

OBJECTIVE

To determine adherence to guidelines for severe asthma care and evaluate regional variability in practice among pediatric intensive care units (PICU).

STUDY DESIGN

A retrospective cohort study of children treated for asthma in a PICU during 2000 to 2003. We utilized the Pediatric Health Information System (PHIS) database to identify patients and determine use of asthma therapies when patients did not improve with standard therapy (inhaled beta-agonists and systemic corticosteroids).

RESULTS

Of 7125 children studied, 59% received inhaled anticholinergic medications. Use of other therapies included systemic beta-agonists (n = 1841 [26%]), magnesium sulfate (n = 1521 [21%]), methylxanthines (n = 426 [6%]), inhaled helium-oxygen gas mixture (heliox) (n = 740 [10%]), and endotracheal intubation with ventilation (n=1024 [14%]). Use of therapies varied by census region. Over half the patients (n = 524) who received ventilation did so for < or = 1 day. Adjusted for severity of illness, use of mechanical ventilation varied significantly by census division; however, much of the variation was among children ventilated for < or = 1 day.

CONCLUSION

Adherence to national guidelines for use of inhaled anticholinergics among critically ill children is low, and marked variation in use of invasive ventilation exists. More explicit guidelines regarding indications for invasive ventilation may improve asthma care.

Intravenous aminophylline for acute severe asthma in children over two years receiving inhaled bronchodilators

BACKGROUND

Since the advent of inhaled beta2-agonists, anticholinergic agents and glucocorticoids, the role of aminophylline in paediatric acute asthma has become less clear. There remains some consensus that it is beneficial in children with acute severe asthma, receiving maximised therapy (oxygen, inhaled bronchodilators, and glucocorticoids).

OBJECTIVES

To determine if the addition of intravenous aminophylline produces a beneficial effect in children with acute severe asthma receiving conventional therapy.

SEARCH STRATEGY

The Cochrane Airways Group register of trials was used to identify relevant studies. The latest search was carried out in December 2004

SELECTION CRITERIA

Randomised-controlled trials comparing intravenous aminophylline with placebo in addition to usual care in children met the inclusion criteria.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies and extracted data. Disagreement in the selection of trials was resolved by consensus. Attempts were made to contact authors to verify accuracy of data.

MAIN RESULTS

Seven trials met the inclusion criteria (380 participants). Methodological quality was high. All studies recruited children with acute severe asthma and requiring hospital admission. Six studies sought participants who were unresponsive to nebulised short-acting beta-agonist and administered systemic steroids to study participants. In two studies where some children were able to perform spirometry, baseline FEV1 was between 35 and 45% predicted. The addition of aminophylline to steroids and beta2-agonist significantly improved FEV1% predicted over placebo at 6-8 hours, 12-18 hours and 24 hours. Aminophylline led to a greater improvement in PEF% predicted over placebo at 12-18 hours. There was no significant difference in length of hospital stay, symptoms, frequency of nebulsations and mechanical ventilation rates. There were insufficient data to permit aggregation for oxygenation and duration of supplemental oxygen therapy. Aminophylline led to a three-fold increase in the risk of vomiting. There was no significant difference between treatment groups with regard to hypokalaemia, headaches, tremour, seizures, arrhythmias and deaths.

AUTHORS' CONCLUSIONS

In children with a severe asthma exacerbation, the addition of intravenous aminophylline to beta2-agonists and glucocorticoids (with or without anticholinergics) improves lung function within 6 hours of treatment. However there is no apparent reduction in symptoms, number of nebulised treatment and length of hospital stay. There is insufficient evidence to assess the impact on oxygenation, PICU admission and mechanical ventilation. Aminophylline is associated with a significant increased risk of vomiting.

Theophylline versus terbutaline in treating critically ill children with status asthmaticus: a prospective, randomized, controlled trial

OBJECTIVE

To compare the efficacy of theophylline, terbutaline, or theophylline combined with terbutaline treatment in critically ill children with status asthmaticus who are already receiving continuous nebulized albuterol and intravenous corticosteroids.

DESIGN

Randomized, prospective, controlled, double-blind trial.

SETTING

Pediatric intensive care unit of a tertiary-care children's medical center.

PATIENTS

Forty critically ill children between the ages of 3 and 15 yrs with impending respiratory failure secondary to status asthmaticus.

INTERVENTIONS

All patients received intravenous methylprednisolone and continuous nebulized albuterol. The three study groups received theophylline plus placebo (group 1), terbutaline plus placebo (group 2), or theophylline and terbutaline together (group 3).

MEASUREMENTS AND MAIN RESULTS

Differences in baseline characteristics, change in clinical asthma score over time, length of pediatric intensive care unit stay, and incidence of adverse events were determined. The three study groups were similar in age, gender, race, asthma severity, and treatment. There were no differences in clinical asthma score over time, length of pediatric intensive care unit stay, or incidence of adverse events between the three groups, with the exception of a higher incidence of nausea in children in group 3. The median hospital cost of medication and theophylline blood levels was significantly lower in group 1 compared with groups 2 and 3 (280 US dollars vs. 3,908 US dollars vs. 4,045 US dollars, respectively, p < .0001).

CONCLUSIONS

Theophylline, when added to continuous nebulized albuterol therapy and intravenous corticosteroids, is as effective as terbutaline in treating critically ill children with status asthmaticus. The addition of theophylline to baseline therapy is more cost-effective when compared with terbutaline alone or terbutaline and theophylline together. Theophylline should be considered for use early in the management of critically ill asthmatic children.