Technology, Computing, and Simulation: Case Report
Placement of a double-lumen endotracheal tube (DLETT) is usually for achieving one-lung ventilation that is frequently used to facilitate surgical exposure by collapsing the lung during thoracic surgery. Arterial hypoxemia and high peak airway pressure are the major problems that may be encountered in one-lung ventilation (1). Malposition of the DLETT with a rate of 38% to 78% is the most cited contributory factor (2,3). Other factors such as manufacturing defects of the DLETT are rarely reported on Medline (4). The case presented herein was attributed to an unusual manufacturing defect in both limbs of the Opti-Port Right Angle Double Swivel Connector of the DLETT. This manufacturing defect is difficult to detect. Therefore, we report this case and make a recommendation about high airway pressure in the placement of a DLETT.
The patient was a 55-yr-old man, 83 kg in weight and 172 cm in height. He had a left upper lobe lung mass and was brought to the operating room without premedication for lobectomy. His medical history revealed no asthma, obstructive nor restrictive lung disease. Arterial blood gas analysis on room air showed pH 7.45, Pao2 100.5 mm Hg, and Paco2 33.1 mm Hg. His pulmonary function tests were normal. Chest radiography showed an ill-defined nodule in the left upper lobe. No tracheobronchial compression caused by the tumor was found on the chest tomography.
After routine preanesthetic preparation, including the leak and obstruction tests for the anesthesia machine (Cato Draeger, Medizintechnik GmbH, Luebeck, Germany), general anesthesia was induced by using midazolam, fentanyl, propofol, and cisatracurium. Ventilation with 100% oxygen via face mask was easily accomplished for 5 min without high resistance. A 35F polyvinylchloride right-sided DLETT (Broncho-Cath; Mallinckrodt, Athlone, Ireland) was then placed in the trachea without difficulty. However, a high resistance was felt at the first manual ventilation. Chest auscultation revealed clear, bilaterally equal and diminished breath sounds. Low lung compliance with a value of 15 mL/cm H2O was noted (Fig. 1A, period a). Only 450 mL of gases could be delivered with 30 cm H2O plateau airway pressure. The position of the DLETT was checked by fiberoptic bronchoscopy and found to be optimal. The right upper lobe orifice was clearly visualized through the right upper lobe ventilation slot. Bilateral endobronchial suction was performed but did not reveal any problems. The breathing circuit was rechecked but no abnormality or kinking was found. Severe bronchospasm was then suspected and treated with hydrocortisone 100 mg IV and aminophylline 250 mg IV drip. The patient’s hemodynamics were stable and pulse oximetry saturation showed 100% with 100% Fio2 throughout this period.
Despite the high airway pressure, an adequate minute volume (7300 mL) could be delivered by increasing ventilated frequency up to 16 times/min in two-lung ventilation. However, when clamping the left-sided connector tube for one-lung ventilation, a significant decrease of compliance to 7 mL/cm H2O was noted (Fig. 1A, period b). Only 250 mL of gases could be delivered with 35 cm H2O plateau airway pressure. Pulse oximetry saturation gradually decreased to 90%. To resolve this problem, one of our staff suggested changing both limbs of the OPTI-PORT™ Right Angle Double Swivel Connector with the Y-shaped adaptor to a new one. The airway resistance decreased immediately. Lung compliance increased to 55 mL/cm H2O (Fig. 1A, period c). Bilateral breath sounds also became louder. We explored both limbs of the connector and found that both had an artificial plastic membrane with a tiny fissure in the side arm orifice (Fig. 1B). After exchanging the new connectors, resection of the left upper lobe proceeded uneventfully under right-lung ventilation. The postoperative course was uneventful and the patient was discharged home 1 wk later.
High airway pressure with or without arterial hypoxemia after a DLETT intubation is a common problem.1 Failure to solve this airway problem may result in a range of problems, from transient desaturation to brain damage and death (5,6). In the common three-step checking methods, airway problems are explored from the patient side, breathing circuit, and then anesthetic machine. In the patient side, the most common causes are hyperreactive airway or secretion. This can be detected with a stethoscope. In the breathing-circuit, the most frequent causes are kinking and malposition of the DLETT (2,3). This is usually solved after repositioning of the tube to the correct position under the guidance of a fiberoptic bronchoscope (2,3). The last check is the anesthesia machine. Its problems can be eliminated by a preoperative test of the anesthesia machine or by using an Ambu bag to ventilate the adaptor of the DLETT and patient directly. In this case, the common approach did not resolve the problem. Because we could not resolve the problem and diminished breath sounds persisted, we suspected that there was an obstruction somewhere in the breathing circuit. We had inspected all parts of the DLETT. Only the connectors and adaptor were not checked. We exchanged them and the problem resolved immediately. We discovered additional membranes with a tiny fissure in the side arm orifice of both limbs of the connectors. The tiny fissures allowed a small portion of the gases to flow through, but resulted in high airway pressure during ventilation. However, this partial obstruction still allowed 450 mL of gases being delivered with 30 cm H2O plateau airway pressure in two-lung ventilation. Thus, we could not initially find the real problem and made a mistaken diagnosis, which resulted in the patient receiving inappropriate treatments.
Although many ventilation problems concerning obstruction or leakage have been reported because of malfunction of ventilation equipment (7,8), or a manufacturing defect of an endotracheal tube (4,9–12), most problems could be easily detected by either the mechanical alarm for gas leakage or the use of a suction tube or fiberoptic bronchoscope. In this case, the defect was difficult to localize in either the pre-use checkout or during the event because of its obscure localization (Fig. 2). In Decision Making in Anesthesiology (13), there is an algorithm to address increased peak airway pressure. It is useful for the differential diagnosis of increased peak airway pressure in the use of an endotracheal tube. But it does not describe the connectors and adaptor of a DLETT being checked. The algorithm is not appropriate for checking a DLETT. Therefore, we present a modified algorithm for high airway pressure in the use of a DLETT (Fig. 3). It should be helpful for quicker identification of the problem.
We present an unusual case of a manufacturing defect of both limbs of a connector of a DLETT that was routinely inspected and tested before use. We recommend an additional pre-use check of the connectors and adaptor of a DLETT. Furthermore, our case highlights the importance of maintaining awareness that airway obstruction caused by structural defects can still occur even with high quality, prepacked single-use DLETTs.
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© 2005 International Anesthesia Research Society
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