According to the study authors, bag-mask ventilation should be avoided because it can worsen dynamic hyperinflation or cause barotrauma.
Patient suffering from pneumomediastinum with diffuse subcutaneous emphysema. – Photo: The New England Journal of Medicine.
When evaluating and managing patients presenting with acute life-threatening asthma, if the exacerbation does not resolve relatively quickly, clinicians should begin to look for other causes of respiratory distress of the patient, suggests a review of the literature.
“I think one of the most important points of this review is that asthma it is a self-limited disease and it is important to understand that with proper treatment and prompt response, flares will improve over time,” Orlando Garner, MD, Baylor College of Medicine, Houston, Texas, to Medscape Medical News.
“So I think one of the key points is that if these flares don’t resolve within 24 to 48 hours, clinicians need to start thinking, ‘This could be something else,’ and not get caught up in diagnosing that “This is an asthmatic patient, who is having an exacerbation. If the discomfort does not resolve within 48 hours, it is time to look for other clues,” he emphasized.
Proper classification is key management of acute asthmaGarner and colleagues note. A simplified severity score for asthma assessment in the emergency department (ED) may help in this regard.
Depending on the presence or absence of a series of signs and symptoms key, patients can be easily classified as mild, moderate or severe asthmatics. “Static and dynamic evaluations of acute exacerbation of asthma in the emergency department may also help classify patients,” the authors add.
Static assessment involves assessing the severity at the time of presentation, which in turn determines the aggressiveness of the initial treatment.
Objective static assessments include the expiratory flow measurement (PEF) or the forced expiratory volume in the first second (FEV 1 ). A severe exacerbation is generally defined as a PEF or FEV 1 of less than 50% to 60% of predicted normal values, the authors note.
Dynamic evaluation is more useful than static evaluation because it measures response to treatment. “Failure to improve expiratory flow rates after initial bronchodilator therapy with ongoing or worsening symptoms suggests the need for hospitalization,” Garner and his colleagues note.
The main goals of treatment for patients with acute asthma are reversal of bronchospasm and correction of hypoxemia.
These are achieved at least initially with conventional agents, such as repeated doses of inhaled short-acting ß2-agonists, inhaled short-acting anticholinergics, systemic corticosteroids, and sometimes intravenous magnesium sulfate.
If there is concomitant hypoxemia, oxygen therapy should also be started. Patients who have evidence of hypercapnic respiratory failure or diaphragmatic fatigue should be admitted to the intensive care unit, the authors note.
For these patients, clinicians should remember that there are other therapies besides inhalers, such as epinephrine and systemic terbutaline.
During a life-threatening asthma episode, airflow in the small and medium airways often becomes turbulent, increasing the work of breathing, the researchers note.
Heliox, a combination of helium and oxygen, reduces turbulent flow, they note, although FiO 2 requirements must be less than 30% for it to work. “Heliox can be used in patients with severe bronchospasm unresponsive to conventional therapies,” the authors note, “[pero] therapy should be discontinued if there is no clinical improvement after 15 minutes of use.”
Although none of the biologics such as dupilumab (Dupixent) have yet been approved for the treatment of acute exacerbations, Garner predicts that they will also become the “future of medicine” for patients with severe asthma.
ventilation in asthma life threatening
Rapid-sequence intubation is generally recommended for patients requiring mechanical ventilation, but as an alternative, “we advocate a slower approach, where we have patients slow their breathing and relax them with something like ketamine infusions and wait.” before giving them a paralytic to see if it improves their work of breathing,” Garner said.
Bag-mask ventilation should be avoided because it can worsen dynamic hyperinflation or cause barotrauma, the authors also stress.
Salvage therapies, such as the use of bronchoscopy with N-acetylcysteine instilled directly into the airways, is another option in cases where mucosal packing is considered to be the primary driver of airflow limitation.
When asked to comment on the review, Brit Long, MD, an emergency room physician at Brooke Army Medical Center in San Antonio, Texas, found the review extremely helpful and well done.
“We see these patients very frequently, and being able to assess them right away and get an accurate picture of what’s going on is very important,” he told Medscape Medical News.
The only thing that’s often more difficult, at least in the ED, is getting a PEF or FEV 1—”both are very helpful if the patient can do them,” Long said, “but if the patient is critically ill, it’s more likely you won’t be able to get those assessments, and if patients are speaking in one-word sentences and are working very hard to breathe, that’s a serious exacerbation, and they need immediate intervention,” he added.
Long also liked all of the essential treatments that the authors recommended patients be given right away, though he noted that Heliox won’t be available in most emergency departments.
On the other hand, he agreed with the authors’ recommendation to adopt a slower approach to mechanical ventilation, if necessary. “I do everything I can to absolutely avoid intubating these patients — you’re not solving the problem with mechanical ventilation, you’re just creating more problems,” Long stressed.
“And while I look at the whole spectrum of patients with asthma, from very mild to severe, these authors did a good job of explaining what the goals of treatment are and what to do with severe ones,” he said.
Source consulted here.