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

A narrative review of theophylline: is there still a place for an old friend?

Background and Objective

Theophylline has been used for decades in human medicine for its psychostimulant, anti-inflammatory, and bronchodilator effects. Historically, in pulmonary medicine, theophylline has been used in the treatment of obstructive pulmonary diseases such as bronchial asthma (BA) or chronic obstructive pulmonary disease (COPD). This review aims to determine whether theophylline still has its place in the therapy of obstructive pulmonary diseases or whether we can even extend its use to other diagnoses such as atropine-resistant cardiac arrests, apnea of prematurity, or others. Moreover, we also aim to determine if there is a rationale for using low-dose theophylline due to its immunomodulatory and anti-inflammatory effect, or if the future of methylxanthines lies in newly synthesized derivates of theophylline such as bamifylline, or doxofylline.

Methods

The narrative review is based on a literature search of the articles indexed in the PubMed database in 2023. We searched the database since the year 2009 using the MeSH terms "theophylline", "aminophylline", and "methylxanthines" and we included original articles in the English language.

Key Content and Findings

Theophylline has a number of adverse drug reactions (ADRs), the most serious of which is its effect on the cardiovascular system. It can cause severe arrhythmias or even cardiac arrest when overdosed. On the other hand, there is still a substantial amount of its applications in current clinical practice.

Conclusions

There is considerable controversy associated with its use in current medicine, which can be attributed both to its narrow therapeutic range and its mentioned cardiotoxic effect. Herein, we summarize the current state-of-art of theophylline and its use in human medicine.

Outcomes of a respiratory therapist driven high flow nasal cannula management protocol for pediatric critical asthma patients

INTRODUCTION

This study aimed to determine if a respiratory therapist (RT)-driven high flow nasal cannula (HFNC) protocol could decrease duration of HFNC use, pediatric intensive care unit (PICU) and hospital length of stay (LOS), and duration of continuous albuterol use in pediatric patients with critical asthma.

METHODS

This was a quality improvement project performed at a quaternary academic PICU. Patients admitted to the PICU between 2 and 18 years of age with a diagnosis of asthma requiring continuous albuterol and HFNC were included. Implementation of an RT-driven HFNC protocol [Plan-Do-Study-Act (PDSA) 1] occurred in October 2017. Additional interventions included weaning continuous albuterol and HFNC simultaneously (PDSA 2; March 2019), adjusting HFNC wean rate (PDSA 3; July 2020), and a HFNC holiday (PDSA 4; October 2021). HFNC duration was the primary outcome. Secondary outcomes included LOS data and continuous albuterol duration. Noninvasive ventilation (NIV), invasive mechanical ventilation (IMV), and 7-day PICU and hospital readmission rates were used as balancing measures.

RESULTS

A total of 410 patients were included. Patient demographics and adjunct therapy use did not differ among the groups. After PDSA 2, mean HFNC duration decreased (26.8-18.1 h). Mean PICU LOS decreased (41-31.8 h). Mean hospital LOS also decreased (86.5-68 h). These outcomes remained stable during PDSA 3 and 4. Continuous albuterol duration and NIV use were unchanged, while IMV use decreased.

CONCLUSIONS

An RT-driven HFNC protocol led to decreased length of HFNC and PICU and hospital LOS for pediatric patients with critical asthma without an increase in adverse events.

Perioperative Care of the Pediatric Patient and an Algorithm for the Treatment of Intraoperative Bronchospasm

Asthma remains a common comorbid condition in patients presenting for anesthetic care. As a chronic inflammatory disease of the airway, asthma is known to increase the risk of intraoperative bronchospasm. As the incidence and severity of asthma and other chronic respiratory conditions that alter airway reactivity is increasing, a greater number of patients at risk for perioperative bronchospasm are presenting for anesthetic care. As bronchospasm remains one of the more common intraoperative adverse events, recognizing and mitigating preoperative risk factors and having a pre-determined treatment algorithm for acute events are essential to ensuring effective resolution of this intraoperative emergency. The following article reviews the perioperative care of pediatric patients with asthma, discusses modifiable risk factors for intraoperative bronchospasm, and outlines the differential diagnosis of intraoperative wheezing. Additionally, a treatment algorithm for intraoperative bronchospasm is suggested.

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.

Pediatric asthma severity score is associated with critical care interventions

AIM

To determine if a standardized asthma severity scoring system (PASS) was associated with the time spent on continuous albuterol and length of stay in the pediatric intensive care unit (PICU).

METHODS

This is a single center, retrospective chart review study at a major children’s hospital in an urban location. To qualify for this study, participants must have been admitted to the PICU with a diagnosis of status asthmaticus. There were a total of 188 participants between the ages of two and nineteen, excluding patients receiving antibiotics for pneumonia. PASS was calculated upon PICU admission. Subjects were put into one of three categories based on PASS: ≤ 7 (mild), 8-11 (moderate), and ≥ 12 (severe). The groups were compared based on different variables, including length of continuous albuterol and PICU stay.

RESULTS

The age distribution across all groups was similar. The median length of continuous albuterol was longest in the severe group with a duration of 21.5 h (11.5-27.5), compared to 15 (7.75-23.75) and 10 (5-15) in the moderate and mild groups, respectively (P = 0.001). The length of stay was longest in the severe group, with a stay of 35.6 h (22-49) compared to 26.5 (17-30) and 17.6 (12-29) in the moderate and mild groups, respectively (P = 0.001).

CONCLUSION

A higher PASS is associated with a longer time on continuous albuterol, an increased likelihood to require noninvasive ventilation, and a longer stay in the ICU. This may help safely distribute asthmatics to lower and higher levels of care in the future.

Anti-inflammatory dosing of theophylline in the treatment of status asthmaticus in children

BACKGROUND

Low-dose theophylline has been recognized for its ability to restore histone deacetylase-2 activity which leads to improved steroid responsiveness and thus improved clinical outcome. We retrospectively evaluated the effect of low-dose theophylline therapy in pediatric patients hospitalized for an acute asthma exacerbation as a proof of concept study.

METHODS

We compared patients who received low-dose theophylline (5-7 mg/kg/day) in addition to current standard of care to patients who were treated with current standard of care alone. The primary outcome of the study was hospital length of stay (LOS). Generalized linear mixed-effects modeling (GLMM) was used to test whether receiving theophylline independently predicted outcomes. A Cox (proportional hazards) regression model was also developed to examine whether theophylline impacted LOS.

RESULTS

After adjustment for illness severity measures, theophylline significantly reduces LOS (β=-21.17, P<0.001), time to discontinue oxygen (β=-15.88, P=0.044), time to spirometric improvement (β=-16.60, P=0.014), and time to space albuterol (β=-23.2, P<0.001) as well as reduced costs (β=-US$2,746, P<0.001). Furthermore, theophylline significantly increased the hazards of being discharged from the hospital (hazards ratio =1.75, 95% confidence interval 1.20-2.54, P=0.004). There was no difference in side effects between patients who receive low-dose theophylline and those who did not.

CONCLUSION

The results of this retrospective study suggest low-dose theophylline may have a positive effect in acute status asthmaticus. This study suggests that further research with a prospective, randomized, double-blinded, placebo controlled trial may be warranted to confirm and extend our findings.

Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit

OBJECTIVE

The goal of this report is to review available modalities for assessing and managing acute asthma exacerbations in pediatric patients, including some that are not included in current expert panel guidelines. While it is not our purpose to provide a comprehensive review of the National Asthma Education and Prevention Program (NAEPP) guidelines, we review NAEPP-recommended treatments to provide the full range of treatments available for managing exacerbations with an emphasis on the continuum of care between the ER and ICU.

DATA SOURCES

We searched PubMed using the following search terms in different combinations: asthma, children, pediatric, exacerbation, epidemiology, pathophysiology, guidelines, treatment, management, oxygen, albuterol, β2-agonist, anticholinergic, theophylline, corticosteroid, magnesium, heliox, BiPAP, ventilation, mechanical ventilation, non-invasive mechanical ventilation and respiratory failure. We attempted to weigh the evidence using the hierarchy in which meta-analyses of randomized controlled trials (RCTs) provide the strongest evidence, followed by individual RCTs, followed by observational studies. We also reviewed the NAEPP and Global Initiative for Asthma expert panel guidelines.

RESULTS AND CONCLUSIONS

Asthma is the most common chronic disease of childhood, and acute exacerbations are a significant burden to patients and to public health. Optimal assessment and management of exacerbations, including appropriate escalation of interventions, are essential to minimize morbidity and prevent mortality. While inhaled albuterol and systemic corticosteroids are the mainstay of exacerbation management, escalation may include interventions discussed in this review.

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.

Asthma changes at a pediatric intensive care unit after 10 years: Observational study

OBJECTIVES:

To describe the change in the management, and outcome of children with acute severe asthma (ASA) admitted to Pediatric Intensive Care Unit (PICU) at tertiary institute, as compared to previously published report in 2003.

METHODS:

This is a retrospective observational study. All consecutive pediatric ASA patients who were admitted to PICU during the study period were included. The data were extracted from PICU database and medical records. The Cohort in this study (2013 Cohort) was compared with the Cohort of ASA, which was published in 2003 from the same institution (2003 Cohort).

RESULTS:

In comparison to previous 2003 Cohort, current Cohort (2013) revealed higher mean age (5.5 vs. 3.6 years; P ≤ 0.001), higher rate of PICU admission (20.3% vs. 3.6%; P ≤ 0.007), less patients who received maintenance inhaled steroids (43.3% vs. 62.4%; P ≤ 0.03), less patients with pH <7.3 (17.9% vs. 42.9%; P ≤ 0.001). There were more patients in 2013 Cohort who received: Inhaled Ipratropium bromide (97% vs. 68%; P ≤ 0.001), intravenous magnesium sulfate (68.2% vs. none), intravenous salbutamol (13.6% vs. 3.6%; P ≤ 0.015), and noninvasive ventilation (NIV) (35.8% vs. none) while no patients were treated with theophylline (none vs. 62.5%). The median length of stay (LOS) was 2 days while mean LOS was half a day longer in the 2013 Cohort. None of our patients required intubation, and there was no mortality.

CONCLUSION:

We observed slight shift toward older age, considerably increased the rate of PICU admission, increased utilization of Ipratropium bromide, magnesium sulfate, and NIV as important modalities of treatment.

Evaluation and treatment of critical asthma syndrome in children

The heterogeneity of asthma is illustrated by the significantly different features of pediatric asthma compared to adult asthma. One phenotype of severe asthma in pediatrics includes atopy, lack of reduction in lung function, and absence of gender bias as the main characteristics. Included in the NIH NAEPP EPR-3 are recommendations for the treatment and management of severe pediatric asthma and critical asthma syndrome, such as continuous nebulization treatments, intubation and mechanical ventilation, heliox, and magnesium sulfate. In addition, epinephrine, intravenous immunoglobulin, intravenous montelukast, extracorporeal membrane oxygenation, and many biological modulators currently under investigation are additional current and/or future treatment modalities for the severe pediatric asthmatic. But, perhaps the most important strategy for managing the severe asthmatic is preventative treatment, which can significantly decrease impairment and risk, particularly for severe acute exacerbations requiring emergency care and/or hospitalization. In order for preventative therapy to be successful, several challenges must be met, including selecting the correct therapy for each patient and then ensuring compliance or adherence to a treatment plan. The heterogeneity of asthma renders the former difficult in that not all patients will respond equally to the same treatment; the latter is only helpful if the correct treatment is employed. Strategies to ensure compliance include education of caregivers and patients and their families. As newer medications are introduced, options for individualized or customized medicine increase, and this may pave the way for significant decreases in morbidity and mortality in severe pediatric asthma.