By Christopher Kroboth
Asthma is a condition in which lower airways narrow and swell and produce extra mucus. This can make breathing difficult and trigger coughing, wheezing and shortness of breath [1].
The CDC reports that 8.3 percent of the pediatric population has asthma and of those 57.9 percent reported a history of having an asthma attack [2].
When treating asthma, remember that it is an airway geometry problem. Imagine the bronchioles are large milkshake straws, nice and large for low resistance airflow to move in and out.
During an asthma attack, that milkshake straw narrows to the diameter of a coffee stir straw. Now visualize a light coat of petroleum jelly on the inside of the coffee straw representing the excess mucus production. See the problem?
Inhalation is an active process, while exhalation is a passive process. It is much easier to inhale past the resistance of bronchoconstriction than passively exhale through resistance of bronchoconstriction.
Exhaling and inhale through a milkshake and coffee stirrer straw to understand. You will feel the increased ventilatory resistance of the smaller straw. For this reason asthma is traditionally a ventilatory problem first. As the inability to ventilate increases and retention occurs this in turn inhibits good end alveolar gas exchange later causing the oxygen saturation to decrease.
Asthma signs and symptoms
Watch this short video of a pediatric patient experiencing an asthma attack.
Here is what to look for during patient assessment:
- Tachypnea to increase oxygen uptake
- Patient self-positions for optimal chest expansion and maximum tidal volume
- Tachycardia from stress response as well as increased respiratory effort
- Hypo- or Hypercapnia depends on the severity of air retention or trapping
Hypercapnia is a worrisome sign of patient severity. Carbon dioxide retention is a sign of inhibited ability to exhale.
Hypoxia is also a late sign in many asthma cases and should be a concern to the provider to determine why the patient’s oxygen saturation is decreasing in a patient experiencing a bronchiole lumen — airway narrowing — problem.
Asthma treatments
Typical treatments for asthma patients include:
- Nebulized beta-agonist, like albuterol, for bronchodialation and some mucus inhibition.
- Nebulized anti-parasympathetic, like Atrovent, to help inhibit the continued production of mucus and augment the Beta-agonist.
- Epinephrine, intramuscular or subcutaneous, especially when nebulizer medication delivery may be inhibited or ineffective. Epinephrine provides bronchodilation effects. Consider strongly the early usage of epinephrine in the patient who shows signs of severe asthma, such as hypercapnia, decreasing oxygen saturation and impending respiratory failure or arrest.
- Magnesium sulfate, a smooth muscle relaxant, works on the bronchiole smooth muscle to decrease constriction and inflammation. Magnesium sulfate is another systemic medication that can help in those patients that are not responding to nebulizer medications.
- Long-lasting corticosteroid to help maintain the anti-inflammatory effects of the quick acting medications. Since most steroids have a longer onset administration is lower on the priority list.
Asthma patient monitoring
Watch this short video showing how vital signs might change as a pediatric patient receives asthma attack treatment.
Here are important signs to measure and monitor during patient assessment and treatment:
- Capnography to help initial bronchoconstriction assessment. Watch for the waveform to transition from shark fin to normal after intervention. If the waveform continues to shark fin, additional intervention is needed.
- Pulse oximetry guides decisions to correlate medication delivery and titration of oxygen.
- Cardiac monitoring of heart rate and rhythm is critical in any patient receiving medications. Tachycardia in a stress state is normal and many asthma medications increase the heart rate to some degree because of their effect on the sympathetic system.
- Blood pressure monitoring because as a patient hypoventilates and isn’t able to exhale their normal volume they begin to retain. This increased volume within the lungs also increases the intrathoracic pressure in turn compressing the vena cava and heart which causes a drop in blood pressure. This is especially seen in children who have smaller trunks than adults.
During the asthma patient assessment always consider the patient’s positioning, work of breathing and appearance. Take into account the environment as well. Is the patient in an environment that is causing the asthma exacerbation? Is there a chemical, mold or other allergen triggering this response? Are you in a school chemistry lab, attic, basement or outside a building? Investigate when and where the patient’s symptoms started in relation to where you are now. What current medications does the patient take for asthma? Are they on oral steroids or do they use an inhaler only as needed? Has the patient ever been hospitalized for asthma and if so to what degree? Have they ever been intubated?
These questions will help understand how severe or potentially severe the patient may become. Remember a child can rapidly transition from “not yet sick” to “sick” in the span of minutes.
References
1. Asthma. (2015, October 17). Retrieved March 01, 2016, from http://www.mayoclinic.org/diseases-conditions/asthma/basics/definition/con-20026992
2. Most Recent Asthma Data. (2015, October 02). Retrieved March 01, 2016, from http://www.cdc.gov/asthma/most_recent_data.htm
About the author
Chris works for Fairfax County Fire and Rescue. He is a Lieutenant currently assigned to the EMS Training Section and serves as the lead instructor for their Paramedic Program in conjunction with Virginia Commonwealth University. Chris also is the U.S. Clinical Education Manager for iSimulate and travels throughout the country teaching simulation and various EMS topics.