Abstract and Introduction
Abstract
Introduction: Severe status asthmaticus (SA) in children may require intubation and mechanical ventilation with a subsequent increased risk of death. In the patient with SA and refractory hypercapnoeic respiratory failure, use of extracorporeal life support (ECLS) has been anecdotally reported for carbon dioxide removal and respiratory support. We aimed to review the experience of a single paediatric centre with the use of ECLS in children with severe refractory SA, and to compare this with international experience from the Extracorporeal Life Support Organization (ELSO) registry.
Methods: All paediatric patients (aged from 1 to 17 years) with primary International Classification of Diseases (ICD)-9 diagnoses of SA receiving ECLS for respiratory failure from both the Children's Healthcare of Atlanta at Egleston (Children's at Egleston) database and the ELSO registry were reviewed.
Results: Thirteen children received ECLS for refractory SA at the Children's at Egleston from 1986 to 2007. The median age of the children was 10 years (range 1 to 16 years). Patients generally received aggressive use of medical and anaesthetic therapies for SA before cannulation with a median partial pressure of arterial carbon dioxide (PaCO2) of 130 mmHg (range 102 to 186 mmHg) and serum pH 6.89 (range 6.75 to 7.03). The median time of ECLS support was 95 hours (range 42 to 395 hours). All 13 children survived without neurological sequelae. An ELSO registry review found 64 children with SA receiving ECLS during the same time period (51 excluding the Children's at Egleston cohort). Median age, pre-ECLS PaCO2 and pH were not different in non-Children's ELSO patients. Overall survival was 60 of 64 (94%) children, including all 13 from the Children's at Egleston cohort. Survival was not significantly associated with age, pre-ECLS PaCO2, pH, cardiac arrest, mode of cannulation or time on ECLS. Significant neurological complications were noted in 3 of 64 (4%) patients; patients with neurological complications were not significantly more likely to die (P = 0.67).
Conclusions: Single centre and ELSO registry experience provide results of a cohort of children with refractory SA managed with ECLS support. Further study is necessary to determine if use of ECLS in this setting produces better outcomes than careful mechanical ventilation and medical therapy alone.
Introduction
Asthma is a growing health problem in the USA, affecting over 9 million children under the age of 18 years. Asthma prevalence is at historically high levels, and it remains the most common cause of hospitalisation among children, with rates highest among African American children.
Status asthmaticus (SA) is also a very common indication for admission to the paediatric intensive care unit (PICU). SA is defined as failure of conventional therapy with progression towards respiratory failure due to asthma. SA can progress quickly to a life-threatening emergency in children. Death rates attributable to asthma and SA have been reported at 2.6 per 1 million children annually (186 children) with a significantly higher rate in African American children aged 0 to 17 years of about 9.2 per 1 million. Patients with previous ICU admissions, recurrent hospitalisation and those requiring mechanical ventilatory support have an increased risk of a fatal outcome.
In addition to the routine administration of continuous nebulised beta-adrenergic agonists with intermittent anticholinergics, corticosteroids and oxygen, adjunctive therapies such as magnesium sulfate, methylxanthines, helium-oxygen mixtures, noninvasive ventilation and intravenous beta-agonists have been employed to avoid respiratory failure and intubation. However, a small number of patients fail to respond to these aggressive treatments and require mechanical ventilation. Up to 20% of children with SA admitted to PICUs require intubation, with a subsequent increased risk of death. An earlier report found that 10% of patients intubated in a PICU had preceding respiratory or cardiopulmonary arrest.
Extracorporeal life support (ECLS) could provide adjunctive pulmonary support for intubated asthmatic patients who remain severely acidotic and hypercarbic in spite of aggressive conventional therapy and unconventional therapies, including inhaled anaesthetics. Although potentially helpful, there has been little experience with ECLS in refractory SA reported. Anecdotal case reports have described its use in adults and rarely in children. No extensive case review of ECLS in SA exists in the literature. We have noted increased need for and use of extracorporeal support for children with SA failing aggressive medical and anaesthetic therapy in our PICU, and sought to evaluate our single centre experience with this approach. For comparison, we queried an international ECLS database to evaluate paediatric experience with the use of ECLS in patients with severe SA.