Vol. 11 •Issue 3 • Page 16
Latex Allergies Easy to Miss in Patients on Home Mechanical Ventilation
By Tracy Schmierer Diehl
Respiratory therapists, parents and caregivers often wear protective latex gloves and use latex suction catheters while performing daily treatments on children who require mechanical ventilation at home. However, these routine undertakings could turn deadly if their young patients develop latex allergies.
“The manifestations of latex allergy can affect the respiratory tract, causing either wheezing or increased mucus production,” explained Ronald M. Ferdman, MD, assistant professor of clinical pediatrics at the Keck School of Medicine and clinical immunologist and allergist at Childrens Hospital Los Angeles. Because home mechanical ventilation patients already have numerous underlying respiratory conditions, clinicians may attribute these symptoms to their chronic problem.
“It could be easy to miss. And these patients are particularly vulnerable, so they are the last patients (for whom) you would want to miss that diagnosis,” he said.
Dr. Ferdman, who is on the Latex Allergy Committee at Childrens Hospital, studied the prevalence of latex allergy in children receiving home mechanical ventilation.1 The idea stemmed from several patients who had significant reactions during surgery or upon exposure to latex, including one patient who experienced anaphylaxis.
Lead study author Craig T. Nakamura, MD, while practicing at Childrens recognized the large number of pediatric patients who were on mechanical ventilation. He decided to investigate if their continual exposure to latex-containing products through frequent hospitalizations and constant suctioning posed a latex allergy risk. Upon testing 57 home mechanical ventilation patients between the ages of 3 months to 23 years, he found 17 patients (about 30 percent) had a positive radioallergosorbent test (RAST) for latex.
“That’s pretty significant because in the general population it is quoted that about 0.1 percent to 1 percent of people are allergic to latex,” reported Dr. Nakamura, who is currently a pediatric pulmonologist at Children’s Lung Specialist, University School of Medicine, Las Vegas.
The longer a patient was on home mechanical ventilation, the longer he or she would be exposed to latex-containing products, the researchers theorized. Yet, there was no difference between the duration of mechanical ventilation with those who had positive RAST tests and with those who had negative tests.
“One patient was on ventilation as short as six months who had latex allergy, and we had patients on (mechanical ventilation) more than five years and they did not have latex allergy,” Dr. Nakamura stated. “So there really was no good way to predict who was and who wasn’t going to turn positive for latex allergy.”
Some symptoms to look out for when it comes to latex allergy include increased secretions when suctioned with rubber catheters and a rash when exposed to latex gloves.
There are three different types of ways latex can cause problems, according to Kenneth T. Kim, MD, assistant clinical professor at UCLA, Long Beach:
• contact dermatitis, an adverse reaction to the act of wearing latex gloves
• allergic contact dermatitis, an allergic reaction to chemicals that were added in the latex manufacturing process
• Type 1 IgE-mediated latex allergy, an allergic reaction to latex proteins.
The third type is the most dangerous reaction, which can cause anything from hives to wheezing to chest tightness, Dr. Kim cautioned. While he agreed with the statement that 0.1 percent to 1 percent of the population is allergic to latex, as much as 10 percent may actually have a postive blood test. He said it’s important to distunguish truly allergic people as having both a positive blood test and symptoms when exposed to latex.
SCREENING AND PREVENTION
It’s a good idea to screen mechanical ventilation patients for latex allergy, especially if they’re scheduled to undergo a surgical procedure where there would be significant rubber exposure, Dr. Nakamura said.
Dr. Ferdman noted, that with most of the patients in the study,1 researchers couldn’t determine latex allergy through symptoms or .history alone. “Yet, when you remove latex from the environment, almost 60 percent improved — a lot more improved than you could have detected clinically,” he said.
Even more important than screening mechanical ventilator patients is prevention, Dr. Ferdman said. When factoring in that 30 percent of the patients in the study were allergic to latex, “I think it would be completely reasonable to start latex-free precautions from the beginning,” he said.
Initially surprised by the high prevalence of latex allergy in the study patients, Dr. Ferdman said that in retrospect, it makes sense when taking into account the constant medical treatment these patients receive. Further, he said their data should be considered, if not generalized, in any patient who requires multiple surgeries or multiple instrumentations.
Most hospitals are taking latex allergy seriously, in part because hospital employees and health care workers are a high-risk population. In case of emergency, latex-free crash carts are placed outside of latex-allergic patients’ hospital rooms. Latex-free equipment is available for the operating room so clinicians don’t place a latex-allergic patient in danger on the operating table.
“In addition, the FDA mandated about a year or two ago that all products need to contain a statement of whether or not they contain latex,” Dr. Ferdman said.
Manufacturers also offer alternative products to latex, which are improving constantly, Dr. Ferdman said.
“There are pretty good substitutes available for just about every medical product out there,” Dr. Kim concurred.
Manufacturers of latex-containing products are doing their part as well.
“Ten years ago, nobody ever heard of latex allergy,” Dr. Ferdman said, offering that the combined effects of HIV and Hepatitis B and C caused an exponential increase in the need for latex gloves.
This, in turn, perhaps caused latex manufacturers to increase production and rinse less thoroughly the latex proteins from their products, he said. Clinicians report that the amount of latex protein in products, such as latex gloves, has decreased over the past few years, which could help slow the rise of latex allergy prevalence.
“We actually might see fewer latex allergy cases in the future. And, if we identify the high-risk people and take precaution in those patients, we could avoid the problem altogether,” he said.
1. Nakamura CT, Ferdman RM, Keens TG, Davidson Ward SL. Latex allergy in children on home mechanical ventilation. Chest. 2000;118:1000-3.
Diehl is a free-lance writer in Gettysburg, Pa.