General Articles: Case Report
The Murphy eye, designed and reported by Murphy in 1941, is a side vent near the distal end of an endotracheal tube (ETT). It was created to prevent complete respiratory obstruction in the event that the open end of the ETT were to become sealed by contact with the tracheal wall or occluded by a mass or mucus plug (1,2). We report a case of a potential complication associated with the manufacturing of an ETT with a Murphy eye.
A 46-yr-old woman (162 cm; 72 kg) was admitted through the emergency department with persistent left flank pain secondary to hydronephrosis from a left ureteral calculus and scheduled for emergency cystoscopy. Her medical history was significant for gastroesophageal reflux disease, reactive airway disease, and mild obesity. After giving her midazolam and fentanyl, general anesthesia was induced with propofol. Endotracheal intubation was facilitated by the administration of succinylcholine and use of a Macintosh #3 laryngoscope blade. The trachea was intubated with a Mallinckrodt Lo-Pro 7.0ETT (Tyco/Mallinckrodt-Nellcor, Pleasanton, CA) with a Mallinckrodt 14F Satin Slip Intubating Stylet previously inserted. General anesthesia was maintained with sevoflurane and 100% oxygen. After a routine cystoscopy, ureteroscopy, and insertion of a ureteral stent, the tracheal extubation was uneventful. The patient was placed in the semirecumbent position and received 4 L of oxygen via a nasal cannula. After several minutes, the patient coughed, and a small piece of plastic was expelled from the patient’s mouth and fell upon her gown (Fig. 1). After a close inspection, the plastic piece was noted to be the punched-out sliver from the ETT’s Murphy eye. Immediately, the patient ceased coughing and was taken to the postanesthesia care unit in stable condition.
Although there are presumed advantages of the Murphy eye, there are complications associated with this side vent. Most of the reported complications have dealt with fiberoptic bronchoscopes or suction catheters being passed down the ETT and becoming lodged in the Murphy eye (3–5). As reported in Kubota et al.’s 1989 correspondence in Anaesthesia (5), a patient’s suction catheter was lodged in the Murphy eye. The ETT and the catheter had to be removed together, exposing the patient to the hazards of reintubation.
Tyco Healthcare/Mallinckrodt was contacted about this complication, and pictures of the ETT with the Murphy eye sliver were forwarded. According to the written response from Alejandra Carrillo, QA Complaints Coordinator, “Currently, there are three process controls in place with the purpose of having the Murphy eye’s sliver removed after the punching operation. At the time the investigation was performed, all three controls were found to be in place. Moreover, the inspection of in-stock material did not yield any defective components. Based on this information, and after performing the risk analysis, we concluded that this could have been an isolated incident with low probability of repetition in the field and a highly unlikely risk to the population who use this kind of product.”
The present case illustrates an unusual manufacturing complication of an ETT with a Murphy eye that had direct clinical consequences. At the beginning of this case, the ETT was externally inspected, the cuff checked, and a stylet inserted. The punched out sliver from the Murphy eye was not noticed on external inspection, and we presume the Murphy eye sliver remained within the confines of the ETT. With the onset of positive-pressure ventilation, the sliver was expelled from the ETT into the patient’s trachea. In review of this complication, we propose that every ETT be inspected internally and externally for any defects before each use.
1. Murphy FJ. Two improved intratracheal catheters. Anesth Analg 1941;20:102–5.
2. Gillespie NA. Endotracheal anesthesia. Madison, WI; University Wisconsin Press, 1963:48.
3. MacGillivray RG, Odell JA. Eye to eye with Murphy’s law. Anaesthesia 1986;41:334.
4. Nichols KP, Zornow MH. A potential complication of fiberoptic intubation. Anesthesiology 1989;70:562–3.
5. Kubota Y, Toyoda Y, Kubota H, et al. A potential complication associated with a tracheal tube with a Murphy eye. Anaesthesia 1989;44:866–7.