Asthma is the most common chronic childhood disease and a frequent reason for pediatric emergency medical treatment. This article will review emergency medical services' (EMS) prehospital assessment and management of acute pediatric asthma exacerbations.
Asthma is a chronic disease characterized by airway narrowing (bronchoconstriction), mucous plugging, and inflammation. Symptoms may be chronic, but during exacerbations or flares, those symptoms worsen, and patients experience acute shortness of breath and difficulty with expiration or forced expiration.
Of the estimated 1 to 2 million pediatric EMS encounters in the United States annually, an estimated 10% to 15% are due to asthma and respiratory distress. Albuterol is the most commonly administered medication to children by EMS. EMS providers should be well-versed in the care of a child suffering from an asthma exacerbation.
EMS must quickly assess the patient and obtain their pertinent history due to time constraints as the ultimate goal of every EMS encounter is transport to an emergency department (ED). EMS providers can use the pediatric assessment triangle (PAT) to assess appearance, work of breathing, and circulation as a quick and validated method to determine the level of care required. The PAT can distinguish a stable patient from respiratory distress, and from respiratory failure. Providers should observe the patient’s work of breathing (including positioning, retractions, nasal flaring, audible wheezing), as well as auscultate for abnormal lung sounds. The lack of abnormal lung sounds may be an ominous sign of poor air movement in a patient at risk for respiratory failure. Pertinent items from the patient’s history include prior diagnosis of asthma, onset, and triggers for the exacerbation, current asthma medications, and prior ED visits or hospitalizations for asthma (including intensive care unit admissions and/or intubations). In children younger than 2 years of age, providers should be aware that bronchiolitis may mimic asthma. In toddlers, providers should also be aware that wheezing can be a sign of foreign body ingestion.
Prehospital evaluation is limited to the quickly obtained history and physical, and vital signs. EMS providers can measure oxygenation with pulse oximetry. Oxygen saturation less than 90% to 94% signals hypoxia. Some EMS systems may employ capnography to measure end-tidal carbon dioxide to measure ventilation.
Once an EMS provider has assessed the patient and concluded the most likely diagnosis is an asthma exacerbation, treatment follows according to the provider's level of certification. Emergency medical technician (EMT)-Basics may administer supplemental oxygen and assist the patient in using their beta-2-agonist inhaler (e.g., albuterol).  EMT-Basics should be aware that a patient's inhaled corticosteroids (e.g., fluticasone) are not proven beneficial in the treatment of an acute exacerbation. The scope of practice of an EMT-Intermediate in administering medications will vary based on their local jurisdiction. 
EMT-Paramedics are authorized to administer medications included in local agency protocols for asthma patients. First-line treatment of an asthma patient with any degree of respiratory distress and/or wheezing should be inhaled beta-2-agonists such as albuterol. Beta-2-agonists counteract bronchospasm by relaxing the bronchial smooth muscle and increasing mucociliary clearance. Albuterol may be administered using a metered-dose inhaler (4 puffs per dose) or as a nebulized solution (2.5 milligrams (mg) per dose for patients less than 10 kilograms (kg), and 5 mg per dose for patients greater than 10 kg). Common side effects include tachycardia and tremors, and more rarely children may experience arrhythmias such as supraventricular tachycardia. For children, the addition of ipratropium bromide (0.5 mg per dose) to albuterol has been shown to decrease hospital admissions in the ED setting. The combination of ipratropium bromide and albuterol may be repeated as needed for persistent respiratory distress.
For children suffering from an asthma exacerbation, ED guidelines recommend early administration (within 1 hour of ED arrival) of systemic corticosteroids in addition to inhaled beta-2-agonists. Systemic corticosteroids work synergistically by up-regulating beta receptors in addition to their anti-inflammatory effects. Systemic corticosteroids speed patient recovery, and early administration decreases ED length-of-stay, hospitalizations, and relapse rates. For pediatric ED patients of all severities, systemic corticosteroid effects are time-dependent, with one study reporting that every 30-minute delay in their administration corresponded to a 60-minute increase in ED treatment time.
Evidence for EMS administration of systemic corticosteroids is not as robust as in the ED setting. EMS agencies in both New York City (1996) and Virginia (2003) retrospectively examined a protocol change authorizing intravenous (IV) methylprednisolone for severe adult asthma patients. The New York City study found no difference in ED LOS or admission rates. By contrast, the Virginia study found a threefold decrease in admission rates. Houston’s EMS agency retrospectively analyzed a protocol change authorizing oral dexamethasone for pediatric asthma patients of all severities. For those patients whose outcomes were known, admission rates decreased from 30% to 21%, and average ED LOS decreased by nearly 1.5 hours. However, systemic corticosteroid administration by EMS was low before and after the protocol change (11% and 18%, respectively), and patients post-protocol change had fewer abnormal respiratory rates than patients pre-protocol change.
With respect to selecting a systemic corticosteroid, oral and IV formulations are commercially available. A review of publicly-available EMS protocols reveals the most common systemic corticosteroid utilized is IV methylprednisolone. However, the bioavailability and physiologic effects are the same between oral and IV systemic corticosteroids. Prednisolone is commercially available as both an oral solution, tablet, and oral dissolving tablet. Dexamethasone is available as an IV liquid which can be administered orally, as well as in tablets that can be crushed. ED studies demonstrating dexamethasone as a single or double dose as non-inferior to prednisolone have caused a change in some emergency providers’ selection of systemic corticosteroid from prednisolone to dexamethasone. However, the original study reporting those results used a longer-acting dexamethasone formulation that has since been taken off the market. Additionally, new EMS reports of dexamethasone resulting in multiple episodes of anaphylaxis and intense perineal burning sensations raise concern for its use in pediatric asthma. Therefore, controversy remains as to whether dexamethasone is an appropriate substitute for prednisolone or methylprednisolone.
Adjunctive Therapies for Critically Ill Patients
For critically ill children, several adjunctive therapies are available. EMS stocks epinephrine for a variety of other conditions and subcutaneous epinephrine rapidly relaxes bronchial smooth muscles. Subcutaneous epinephrine is dosed at 0.01 mg/kg of 1:1000 concentration, with a maximum single dose of 0.3 to 0.5 mg. Alternatively, an epinephrine autoinjector (either 0.15 mg or 0.3 mg) can be used to deploy the drug via intramuscular administration rapidly. Intravenous magnesium for pediatric asthma has some evidence for decreased hospital admissions and is dosed at 50 mg/kg (maximum 2000 mg per dose). Common side effects include hypotension, which is rarely clinically significant and usually responds well to fluid administration. Terbutaline is another bronchodilator which can be administered subcutaneously (0.005 to 0.01 mg/kg, maximum dose 0.4 mg) or intravenously (initial bolus 0.01 mg/kg). Terbutaline can have cardiac side effects such as elevated cardiac enzymes and arrhythmias although this is usually seen after several hours of continuous infusion. Finally, positive pressure or mechanical ventilation may be necessary in rare cases. Noninvasive ventilation with bilevel positive airway pressure (BiPAP) can help stave off intubation and preserves the conscious patient’s respiratory drive. Intubation and mechanical ventilation are the last resort for patients with refractory respiratory failure and/or respiratory arrest. It is difficult to match an asthma patient’s hyperventilation, and lower tidal volumes should be used to avoid barotrauma in the setting of hyperinflation. Finally, intravenous ketamine at sub-dissociative doses is gaining favor as an adjunctive bronchodilator, especially for agitated patients in respiratory distress. However, scant evidence exists for its use in the ED and EMS setting.
As stated above, most of the evidence for EMS treatment of pediatric asthma is extrapolated from studies in the ED setting. Future directions for EMS treatment must come from research originating in the heterogeneous and mobile EMS environment. Medical directors and providers would be well-served by keeping abreast of developments in the literature to ensure protocols contain the most up-to-date evidence. Continuing provider education on the assessment and management of the most common chronic disease of childhood is essential for the proper care of pediatric asthma patients.
|||Shah MN,Cushman JT,Davis CO,Bazarian JJ,Auinger P,Friedman B, The epidemiology of emergency medical services use by children: an analysis of the National Hospital Ambulatory Medical Care Survey. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2008 Jul-Sep [PubMed PMID: 18584491]|
|||Lerner EB,Dayan PS,Brown K,Fuchs S,Leonard J,Borgialli D,Babcock L,Hoyle JD Jr,Kwok M,Lillis K,Nigrovic LE,Mahajan P,Rogers A,Schwartz H,Soprano J,Tsarouhas N,Turnipseed S,Funai T,Foltin G, Characteristics of the pediatric patients treated by the Pediatric Emergency Care Applied Research Network's affiliated EMS agencies. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2014 Jan-Mar [PubMed PMID: 24134593]|
|||Gausche-Hill M,Eckstein M,Horeczko T,McGrath N,Kurobe A,Ullum L,Kaji AH,Lewis RJ, Paramedics accurately apply the pediatric assessment triangle to drive management. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2014 Oct-Dec [PubMed PMID: 24830831]|
|||Delbridge T,Domeier R,Key CB, Prehospital asthma management. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2003 Jan-Mar [PubMed PMID: 12540142]|
|||Pardue Jones B,Fleming GM,Otillio JK,Asokan I,Arnold DH, Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit. The Journal of asthma : official journal of the Association for the Care of Asthma. 2016 Aug [PubMed PMID: 27116362]|
|||Kercsmar CM, Current trends in management of pediatric asthma. Respiratory care. 2003 Mar [PubMed PMID: 12667272]|
|||Rowe BH,Spooner C,Ducharme FM,Bretzlaff JA,Bota GW, Early emergency department treatment of acute asthma with systemic corticosteroids. The Cochrane database of systematic reviews. 2001 [PubMed PMID: 11279756]|
|||Davis SR,Burke G,Hogan E,Smith SR, Corticosteroid timing and length of stay for children with asthma in the Emergency Department. The Journal of asthma : official journal of the Association for the Care of Asthma. 2012 Oct [PubMed PMID: 22978310]|
|||Knapp B,Wood C, The prehospital administration of intravenous methylprednisolone lowers hospital admission rates for moderate to severe asthma. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2003 Oct-Dec [PubMed PMID: 14582090]|
|||Nassif A,Ostermayer DG,Hoang KB,Claiborne MK,Camp EA,Shah MI, Implementation of a Prehospital Protocol Change For Asthmatic Children. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2018 Jul-Aug [PubMed PMID: 29351496]|
|||Dylla L,Acquisto NM,Manzo F,Cushman JT, Dexamethasone-Related Perineal Burning in the Prehospital Setting: A Case Series. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2018 Sep-Oct [PubMed PMID: 29485338]|
|||Hendeles L, Selecting a systemic corticosteroid for acute asthma in young children. The Journal of pediatrics. 2003 Feb [PubMed PMID: 12584519]|
|||Fernandes RM,Oleszczuk M,Woods CR,Rowe BH,Cates CJ,Hartling L, The Cochrane Library and safety of systemic corticosteroids for acute respiratory conditions in children: an overview of reviews. Evidence-based child health : a Cochrane review journal. 2014 Sep [PubMed PMID: 25236311]|
|||Miller AG,Breslin ME,Pineda LC,Fox JW, An Asthma Protocol Improved Adherence to Evidence-Based Guidelines for Pediatric Subjects With Status Asthmaticus in the Emergency Department. Respiratory care. 2015 Dec [PubMed PMID: 26106203]|
|||McIver M,Stoudemire W,Smith-Ramsey C,Panigrahi M,Walsh-Kelly C,Rutman LE, Improving Timeliness of β-Agonist and Corticosteroid Administration in Patients With Acute Wheezing. Pediatric emergency care. 2017 Sep [PubMed PMID: 28816890]|
|||Sills MR,Ginde AA,Clark S,Camargo CA Jr, Multicenter analysis of quality indicators for children treated in the emergency department for asthma. Pediatrics. 2012 Feb [PubMed PMID: 22250025]|
|||Adcock IM,Maneechotesuwan K,Usmani O, Molecular interactions between glucocorticoids and long-acting beta2-agonists. The Journal of allergy and clinical immunology. 2002 Dec [PubMed PMID: 12464934]|
|||Gries DM,Moffitt DR,Pulos E,Carter ER, A single dose of intramuscularly administered dexamethasone acetate is as effective as oral prednisone to treat asthma exacerbations in young children. The Journal of pediatrics. 2000 Mar [PubMed PMID: 10700684]|
|||Stead L,Whiteside T, Evaluation of a new EMS asthma protocol in New York City: a preliminary report. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 1999 Oct-Dec [PubMed PMID: 10534036]|