Pneumothorax and cardiac arrest caused by speaking valve mistaken as moisture exchanger: an incident report.

Editor—Patients with tracheostomy represent an increasing population, which is at risk of major airway complications because of invasive procedures, comorbidities, and lack of experience of the staff managing these patients. 2 An 81-yr-old female patient underwent an elective surgery to replace a temporary percutaneous tracheostomy by a conventional surgical tracheostomy. The former surgery was performed to protect the tracheobronchial tree from aspiration after stroke with left-sided hemiplegia and aphasia. During the surgical tracheostomy under general anaesthesia, the uncuffed tracheal cannula was removed and an oral tracheal tube was used for the lung ventilation. After the tracheostomy had been established, a standard cuffed tracheostomy tube (I.D. 10.0 mm) was inserted. At the end of the surgery and after establishing spontaneous breathing, a speaking valve, previously connected to the uncuffed tracheal cannula before the surgery (Fig. 1A), was attached to the cuffed tracheostomy tube. This device resembled and was thought to be a moisture exchanger device (Fig. 1B) with oxygen supply. Two minutes later the patient started coughing and developed progressive bradycardia resulting in an asystole. Chest compressions and manual ventilation were started. After lung auscultation, which revealed bilateral dull spastic sounds and suspected tension pneumothorax, two 14-gauge cannulas were inserted bilaterally at 2/3 intercostal space. A bolus of epinephrine 1 mg was given. Spontaneous circulation returned after 13 min of manual chest compression. Chest X-ray, performed at ICU, confirmed the pneumothorax on the left side and emphysema of the skin. The following endoscopy did not find any other bronchial and oesophageal lesions. During the next 5 days, the circulation and cerebral function recovered to the state the patient had before the accident and the patient was discharged from the hospital on the 10th postoperative day. A speaking valve is a one-way airflow device, which is attached to the distal end of the uncuffed tracheostomy tube to allow speaking trials. The expiration is blocked (Fig. 1C); during the breathing, the air passes around the proximal end of the tracheostomy tube through the vocal cords and then exits via the nose and mouth. The application of a speaking valve, mistaken as moisture exchanger in the present case, had led to blocked expiration in a cuffed tracheostomy tube, increased end-expiratory pressure above the physiological values within seconds with following cardiac arrest. The acute lesion of pulmonary tissue and subsequent positive pressure ventilation led to tension pneumothorax. The attached oxygen supply probably accelerated this pressure increase. The visual similarity between speaking valve and moisture exchanger (Fig. 1A and B) and the limited capability of the patient with severe neurological problems were obviously the reasons for this life-threatening event. In order to prevent the potential misuse, according to European law regulation on medical devices [http://www.iso. org/iso/home/store/catalogue_ics/catalogue_detail_ics. htm? Csnumber=50335 (accessed 29 October 2012)] speaking valves are supplied with a graphical symbol (black triangle with an exclamation sign inside it, Fig. 1A). However, it is known that even experienced clinicians neglect such graphical symbols on medical devices. 4 We believe that fatal events because of mistaken assembly of the breathing system components can be prevented by: (i) intelligent design of medical devices; (ii) appropriate education of the staff (including storage and double-check of the equipment); and (iii) reporting of the incidents to authorities in-charge and to medical community. no flow O2 flow inspiration only