Tracheal and bronchial obstruction following cyanoacrylate aspiration in a toddler

Abstract

Introduction. Cyanoacrylates are a common class of household substances used as adhesives and are commonly sold under brand names such as Super Glue®, Krazy Glue®, and others. We are reporting a case of accidental cyanoacrylate adhesive aspiration by a toddler complicated by tracheal and bronchial obstruction. Case Report. A toddler ingested a low-viscosity cyanoacrylate product and developed a severe, persistent cough. Initial vital signs, oxygen saturation, lung sounds, and chest radiograph were unremarkable. Rigid bronchoscopy was performed and several pieces of glue were removed from both main stem bronchi. The child made a full recovery after a 10-day hospital stay. Discussion. Cyanoacrylate ester polymers are hard, glassy resins that exhibit excellent adhesion to a variety of materials. Aspiration of these products is a poorly described clinical entity. Conclusion. The low viscosity of cyanoacrylate adhesive formulations makes aspiration of these products a rare but potentially life-threatening exposure. Management centers upon supportive care and consideration of rigid bronchoscopy for removal of adherent glue.

Keywords: :

• Aspiration
• Cyanoacrylate
• Toxicity

Introduction

Cyanoacrylate ester polymers are hard glassy resins that exhibit instant adhesion to a wide variety of materials such as metals, plastics, fabrics, woods, ceramics, and more, and are used in an array of household applications. They can be found with varying physical qualities such as viscosity and drying or “curing” time, and are chosen based on the intended application. The utility of these adhesives arises from the electron-withdrawing moieties adjacent to the polymerizable double bond, which accounts for both their fast cure rate and their ability to adhere to a wide variety of surface structures. The liquid monomers polymerize via an anionic mechanism when brought into contact with any basic surface. The presence of weakly basic surface moisture is adequate to initiate the curing reaction. These adhesives are potentially hazardous dermal and mucous membrane bonders because of the presence of moisture and protein in the skin (1).

Several cyanoacrylate adhesives are available commercially today, many with various differences in features. The base monomers are of such low viscosity that they are often inconvenient for use and therefore must be formulated with stabilizers, thickeners, and polymerizing inhibitors, such as hydroquinone, to produce desired chemical properties for the application at hand (1). Typically cyanoacrylate-type products with greater viscosity have a longer curing time that allows for positioning of parts and produces a much stronger bond. Less viscous glues, which have a higher penetrating or wicking ability, sometimes travel several inches into the parts to be bonded such as Balsa wood. For this reason low-viscosity cyanoacrylate glues are prized by modelers. We report a toddler who accidentally aspirated cyanoacrylate “super glue” used in model car construction. In addition to describing our experience, we propose a protocol for the management of cyanoacrylate aspiration.

Case report

A 19-month-old toddler was witnessed ingesting a cyanoacrylate product, ZAP CA (pink label) by Pacer Technologies (Fig. 1), used by her father to build model cars. The volume of ingested material was initially estimated at approximately 7 mL. Shortly after ingestion, the child developed a severe, persistent cough that forced presentation to a local emergency department. Vital signs on presentation included a heart rate of 204 beats per minute, blood pressure of 96/36 mmHg, and oxygen saturation of 98% on room air. Respiratory rate was not determined because of continuous coughing. Physical examination was notable for clear lung sounds with no evidence of caustic injury in the mouth or pharynx. Cured glue was present on the hard palate, but did not create any oropharyngeal obstruction. A chest radiograph was normal, but the child produced several globules of amorphous clear material after vigorous coughing.

Fig. 1.  Zap CA (pink label).

Rigid bronchoscopy was performed to ascertain the cause of the persistent coughing. The vocal chords and larynx were normal, but large amounts of adherent glue formed a cast that nearly obstructed the trachea. Several pieces of glue were removed from both main stem bronchi using the rigid bronchoscope, with additional material visualized beyond the tertiary arborizations of the bronchial system bilaterally. No glue was observed in the esophagus and no gastric injury was identified. The child was intubated following the procedure, and maintained on 50% inspired oxygen.

Repeat chest radiographs obtained following bronchoscopy demonstrated right upper lobe collapse, scattered subsegmental atelectasis in the upper and lower left lobes, and pulmonary edema. These sequela were thought to be caused by physical trauma of picking the glue off the bronchi combined with chemical irritation of the glue causing a burn-like injury to the lining of the airway. Intravenous steroids, inhaled beta agonists, and prophylactic antibiotics were utilized to help maintain an open airway and to prevent opportunistic infections. The child remained intubated for eight days and was discharged from the hospital after a ten-day stay. No lasting abnormalities were found on follow-up.

Discussion

While exposure to cyanoacrylate adhesives via dermal and ocular routes is well reported in the literature (2,3), aspiration of cyanoacrylate products is a poorly described clinical entity. The American Association of Poison Control Centers received 10,250 calls involving cyanoacrylate adhesive exposures in 2005 (4). Of theses calls, 40% were involving children under 6 years of age. Only two of these cases were reported to cause “major effects,” but neither was coded as aspiration. We are unaware of any other reports of cyanoacrylate aspiration in toddlers. This case involved aspiration of ZAP CA (pink label), which contains 60–100% ethyl-2-cyanoacrylate and 0–1% hydroquinone, as reported by the product material safety data sheet. Its low viscosity and delayed cure time of 5 seconds allows the glue to be aspirated before polymerization.

A variety of pubic health and safety issues surfaced in the course of evaluating this patient and her exposure. Although the ZAP CA product label is compliant with all applicable laws and regulations, it failed to provide complete information regarding the identity of ingredients, their potential toxicity, and first aid measures. For example, the label does not specify that although this product uses a snap-on cap, it is not child resistant and can be easily opened with little effort. The package safety label describes the product as an irritant and recommends medical attention for “eye or internal contact” only. Brief warnings to “use with adequate ventilation,” and to “keep out of reach of children” are listed on the product label, however information regarding responses to inadvertent exposure or poisoning was incomplete or nonexistent. Also, the product label makes no recommendation to call a poison information center for medical advice. Similar problems on product labels, including those for methacrylic acid artificial fingernail glue primers, have been noted by others (5).

The manufacturer's telephone number was not listed on product labels and had to be obtained from Internet or toxicology database searches. When contacted, the manufacturer was reluctant to disclose the identity and concentration of the product's ingredients. Although a Material Safety Data Sheet (MSDS) for ZAP CA is available online, it does not disclose the exact concentration of cyanoacrylate or hydroquinone. Moreover, the MSDS contained limited information related to organ-specific injury, and failed to mention possible pulmonary complications following aspiration. The lack of sufficient information on MSDSs for determining appropriate medical treatment of exposures is an ongoing concern with related household products (5).

Another problem we encountered was the absence of pertinent information regarding the management of exposure to the products involved. Because the toxicity observed in our patient was inconsistent with that commonly associated with this class of compounds, we consulted a number of resources. POISINDEX®, a well-regarded product information database, correctly identifies the components of the glue but does not accurately describe the concentration of its ingredients. Furthermore, this database states that pharyngeal or esophageal adhesions are unlikely since the monomer rapidly polymerizes in the mouth and exposure is unlikely to cause toxicity other than adhesion to mucus membranes, skin, and eyelids (6). Information contained in toxicologic emergency textbooks described the possibility of corneal abrasions following eyelid contact, but made no mention of potential involvement of other organ systems (7,8).

ZAP CA products are sold in small ¼ ounce to 4-ounce sized plastic bottles with non-child resistant caps. We found dozens of cyanoacrylate adhesives advertised on various websites; while some product packaging may be tamper resistant, none appeared to be child-resistant. Given the widespread availability of these household materials, their potential toxicity, the lack of child-resistant packaging, and vague package labeling, the dearth of information pertaining to treatment is concerning.

As demonstrated by this case, aspiration of cyanoacrylate adhesives with airway obstruction is a potentially life-threatening event. If presented with a case of cyanoacrylate adhesive aspiration, we propose the following management recommendations.

1. Prompt transport to a nearby emergency department.

2. Administer supplemental oxygen as needed based on the patient's oxygen saturation and clinical status.

3. Treatment with a cool-mist nebulizer (9) and bronchodilators to help improve respiratory flow rates of the obstructed upper airways.

4. Obtain a chest radiograph to visualize any obstruction of the airway. Be aware that negative findings on a chest radiograph and lack of serious symptoms do not rule out aspiration of the product.

5. Transfer to a healthcare facility with experience in pediatric medicine.

6. Proceed to the operating room for bronchoscopy, esophagoscopy, and removal of the glue from the airway as needed.

7. Intubation and treatment with intravenous steroids, inhaled beta agonists, and prophylactic antibiotics to help maintain an open airway and to prevent opportunistic infections.

Conclusion

The low viscosity of cyanoacrylate adhesive formulations used in modeling makes aspiration of these products a rare but potentially life-threatening exposure. Treatment management centers upon good supportive care and early consideration of rigid bronchoscopy for removal of adherent glue. The use of child-resistant packaging is likely to be protective.