Paper
Overcoming dose-counting mechanisms on metered-dose inhalers for urgent treatment in the operating room.
Published Nov 1, 2009 · Timothy E. Smith, Leah B Templeton, S. W. Galyon
Anesthesia and analgesia
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Abstract
To the Editor: We report difficulty encountered when using the newly packaged Ventolin hydrofluoroalkane (HFA) metered dose inhaler (MDI; GlaxoSmithKline, Philadelphia, PA) for the treatment of acute intraoperative bronchospasm. A 14mo-old girl with achondroplasia, weighing 8 kg, presented for decompression of occipital cervical stenosis. This patient’s medical history was complicated by severe obstructive sleep apnea and chronic pulmonary congestion requiring continuous supplemental oxygen by nasal cannula. An IM injection of ketamine and glycopyrrolate was given preoperatively. After an uneventful inhalation induction and establishment of IV access, a 4.0 uncuffed endotracheal tube was placed with fiberoptic guidance via a laryngeal mask airway. Marked expiratory wheezes were heard bilaterally. An albuterol MDI was removed from the emergency medicine drawer of the Ploss cart. However, we were surprised to find that the hospital pharmacy had changed albuterol products to incorporate use of a product with an MDI dosecounting mechanism. There had been no effective method of drug delivery to pediatric patients before adopting this device and including it in all of our pediatric anesthesia carts. The bronchospasm continued and an “old” Proair HFA (Teva Pharmaceuticals USA, North Wales, PA) was found and used to manage the event. The Proair HFA was placed in a 60-mL BD syringe (Becton Dickinson, Franklin Lakes, NJ), which was connected to the circuit via the ETco2 port, an old method that is well known to most. The albuterol was then delivered via the circuit. This change in pharmacy stock resulted in delayed treatment of intraoperative bronchospasm. Several anesthesiologists and respiratory therapists worked together to develop a means to deliver albuterol by MDI with a dose-counting mechanism to a patient whose lungs were mechanically ventilated intraoperatively. A 3.0 Mallinckrodt (Glens Falls, NY) endotracheal tube adaptor fit the Ventolin HFA “cap” quite snugly and also connected with a standard end-tidal CO2 detector tubing port at the anesthesia circuit (Fig. 1). This allows for adequate delivery of the albuterol to the patient. It should be noted that the dose-counting mechanism that we encountered cannot be removed without significant physical force and a makeshift tool. The published outpatient dose for all patients is 2 puffs/delivery every 4 – 6 h to a maximum of 12 puffs per day. However, treatment of intraoperative bronchospasm in a patient with full monitors frequently exceeds this dose. In the operative setting, patients are monitored for excessive -2 stimulation, namely, tachycardia. In March 2003, the U.S. Department of Health and Human Services Food and Drug Administration Center for Drug Evaluation and Research released a “Guidance for Industry” regarding the integration of dosecounting mechanisms into MDI drug products. Before the integration of dose-counting mechanisms, patients needed to guess how many doses were left in their MDI devices. This left patients with the option of either discarding MDIs with remaining active drug or using MDIs devoid of active drug. Thus, the Agency recommended that manufacturers integrate dose-counting devices into all newly developed MDI devices. It is important to note that because of the international ban on chlorofluorocarbon propellants, all MDIs are being reformulated to HFA propellants, making them “newly developed devices.”
Case ReportThe new Ventolin HFA MDI with dose-counting mechanism delayed intraoperative bronchospasm treatment, but an old Proair HFA was found and used to effectively deliver albuterol to a pediatric patient.
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