Don’t measure asthma exacerbations with outdated methods
January 1, 1998 4 minutes read
Don’t measure asthma exacerbations with outdated methods
Measuring asthma symptoms should be a top priority for ED nurses, urges Laura Criddle, RN, MS, CEN, CCRN, a flight nurse at Brackenridge Hospital in Austin, TX. "I can’t stress enough how important it is to actually measure the disease," she says. "You wouldn’t dream of treating a child’s fever without taking a temperature, so why is it we treat asthma without objectively documenting it?"
It’s impossible for an ED nurse to determine high-risk patients by how "bad" they look. "It’s been proven time and again that you cannot just look at a patient and determine their severity," says Colleen Andreoni, RN, MS, CEN, TNS, asthma clinical nurse specialist at MacNeal Hospital in Berwyn, IL. "The best way to measure severity is with objective measurement."
Nurses should take the initiative to teach patients to measure their peak flow. "Waiting for a respiratory therapist sends a message that this is something complicated that takes a specialist to do," Criddle says. "The truth is, this takes only a few seconds and anybody can do it at any time. That is the message we want to be sending to patients."
Old methods still widely used
Traditional ways of measuring asthma severity are no longer current, yet are still being used in many EDs, notes Criddle. "Chest x-rays are predictably abnormal and are almost never indicated unless the patient is severe enough to be admitted to the ICU," she says. "And, rarely is a routine asthma [exacerbation] associated with a bacterial infection, so, unless you think the patient may have pneumonia, there is no point in getting a complete blood cell count."
Arterial blood gas (ABG) monitoring also does little to add to the routine assessment of asthma, she says. "It’s not until a patient gets very severe that you actually see any significant abnormalities, and they can be misleading, since normal results may not indicate a normal patient," warns Criddle. "It’s also one of the big reasons patients don’t come into the ED, because it’s invasive and painful."
Traditionally, breath sounds were relied on, but they can be misleading. "We’ve relied on those way too much in the past—we can’t be making clinical decisions based on what we hear in the chest," Criddle stresses. "Breath sounds just don’t correlate very well with peak flow, and yet we’ve acted like they’re a gold standard of care."
Wheezing is not detectable until air flow is already significantly decreased, and breath sounds normalize long before pulmonary functions do, Criddle notes. "They are hard to interpret because they get better on both ends of the spectrum—before you quit breathing, you quit wheezing, and you quit wheezing long before you really get better," she says. "Also, how do you know five minutes later whether it’s better or worse? Little changes are tough to pick up."
Here are more effective ways to measure asthma severity:
Pulse oximetry. Ideally, pulse oximetry should be measured at triage, although oxygen saturation does not measure asthma severity. "Of all your vital signs, saturation is the single best measure of how your patient is doing," says Criddle. Unless asthma patients have a pulse oximetry value of 90% or better, they should be put on oxygen, she advises.
Traditionally, hypoxia wasn’t considered a significant problem for asthma patients, but, now, this is not the case, she says. "Hypoxia is not any more normal for the asthma patient than it is for the rest of us," she says.
Peak flow meters. This is a simple and inexpensive way to measure the patient’s maximum possible outward air flow. "It only take a few seconds, and monitors are cheap and portable, but there are still many EDs that aren’t doing it," says Criddle. Peak flows should be monitored before and after each treatment and prior to discharge, she recommends.
Metering allows patients to see problems in advance, instead of waiting for symptoms to occur. "They usually don’t feel it coming until they reach less than 75% capacity, and by that time they’re already on the downhill slope," explains Criddle.
Clinical signs. When assessing asthma patients, ED nurses should look for conversational dyspnea, use of accessory muscles, nasal flaring, respiratory rate, and breath sounds, says Andreoni.
Patients who need to sit up in order to breathe, are using sternocloidmastoid muscles, or who are diaphoretic are almost always more severe, says Criddle. "Patients who are able to tolerate a supine position aren’t as severe; sitting patients may have peak flows half of that," she notes. "It is somewhat subjective since you can’t put a number to it like you can with peak flow, but it’s good for an across-the-room triage assessment."
The patient’s ability to speak is also a reliable measure of severity. "To make it more quantifiable, have the patient take a deep breath, and count one, 1000, two, 1000 until they need to take another breath," she recommends.
Patients may come to learn that on their good days, they reach 15, while a bad day might only be seven. This information can help them decide whether an ED visit is necessary. "This is a technique they can use when they don’t have a peak flow meter with them," says Criddle.
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