Vent Strategies for Severe Asthma

What is the most successful way to prevent intubation of patients with severe asthma? “Don’t just look at the data provided to you by monitors in the ICU,” says Pierre Vauthy, MD, director of pediatric pulmonary medicine and pediatric critical care at ProMedica Toledo Children’s Hospital in Toledo, Ohio. “Always listen with your stethoscope.”

According to a recent study, of 29,430 admissions with a primary diagnosis of asthma, 10.1% were admitted to the ICU and 2.1% were intubated. “The risk of in-hospital death was significantly greater in patients who were intubated but not admitted to the ICU, than those who were admitted to the ICU and intubated and patients with more severe comorbidities. On average, intubated patients stayed in the hospital 4.5 days longer and incurred more than $11,000 in additional costs; patients admitted to the ICU stayed 1 day longer and accounted for $3,000 in additional costs versus standard admissions,” according to the study.[1]

Vauthy says that in his practice, those statistics rise to 20% of patients admitted to the ICU, with 1% to 2% of those patients intubated. Vauthy said that despite the high numbers, patients have a much lower admittance rate now than in previous years. He attributes the decrease in admittance to a better understanding of the disease, the use of inhaled corticosteroids and better patient medication adherence. “When I first started as a pulmonologist 36 years ago, we had many more admissions,” he said. “Today, when patients are diagnosed with asthma, they are treated appropriately and rarely, if ever, have to be hospitalized.”


Providing Intensive Care
However, for those patients who are admitted to the hospital, and the subset intubated in the ICU, the severity of a patient’s condition can escalate quickly. Vauthy says the typical admitted patient is one who experiences respiratory distress despite routine care provided, requires increased amounts of oxygen, or doesn’t respond to conventional therapy, including 2-3 treatments of bronchodilator aerosols or 2-4 inhalations of metered dose bronchodilator with a spacer.

Vauthy advises that patients who are admitted to the hospital should be monitored closely, as they may require intensive care and intubation with ventilating support. “If your patient is nonresponsive to initial therapies, the next step a respiratory therapist should approach is to auscultate the patient to determine if he or she is moving air,” Vauthy advised. Poor response to bronchodilators and a need for supplemental oxygen requires ICU care, initiation of IV steroids, pulse oximetry and continuous monitoring of vital signs.

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“If a patient has poor air exchange and a productive cough, the patient may require a mucolytic with a bronchodilator as well as postural drainage with a vest or a percussor,” Vauthy says. When a respiratory therapist encounters the worst type of respiratory distress, not breathing due to a lack of oxygen, it is imperative to know whether the patient has a lot of secretion in the lungs. “Some patients with asthma have a tremendous amount of mucus, and it is part of our job as respiratory therapists to get rid of it,” he says. “To reduce the amount of mucus, provide aerosols and mucolytics, such as acetylcysteine (Mucomyst).”

If the patient is able, respiratory therapists should administer chest percussions or use a chest vest to mobilize mucus out of the lungs. “The real complications arise when you have to intubate a patient with asthma,” Vauthy says, adding that intubation is determined by poor air movement, severe retractions and deterioration of the pulse oximetry. “You must first paralyze the patient to prevent the patient’s further pulmonary deterioration. If he or she is fighting you, you will not be able to intubate, causing further problems, such as obstruction of the trachea from thick mucus.”

When paralyzing a patient, it is essential to use as little volume as is necessary to affect the appropriate ventilation, Vauthy says. But how does one determine if a patient has adequate ventilation? “Use a stethoscope,” Vauthy advises. “Watch the patient’s chest to see if it rises adequately and listen to learn if the patient is ventilating in both lungs.” If you improperly intubate, only one lung could be ventilating, causing the other lung to collapse. In the worst case scenario, an intubation of the esophagus would result in patient death.

Patients who are ventilated must have an arterial line in place prior to intubation, or shortly after being ventilated, to measure the patient’s carbon dioxide and oxygen levels. “Appropriate tidal volumes need to be provided by the ventilator,” Vauthy says. “The average adult requires 400-500 milliliters. Too much volume can cause barotraumas, a very common side effect that requires intubation and ventilatory support.”

Avoiding Admission Altogether
Though major complications due to intubation of patients with asthma can be avoided by skilled respiratory therapists, Vauthy says that hospital admissions and minor complications can first be averted by proper use of medication and patient education on treating exacerbations. He recommends use of aerosols for children under 6 years of age and a metered dose inhaler with a spacer for patients over that age.

If a patient does present with complications, always practice what Vauthy calls a lost art: listening to patient’s chest with a stethoscope. “It is crucial for respiratory therapists to not rely on the data recorded by the pulse oximetry machine alone, but to determine if the patient’s breathing is adequate.”

Kelly Wolfgang is on staff at ADVANCE. Contact: kwolfgang@advanceweb.com.

References:

[1]. Pendergraft TB, et al. Rates and characteristics of intensive care unit admissions and intubations among asthma-related hospitalizations. Ann Allergy Asthma Immunol. 2004;93(1):29-35.

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