A simple model for training in one lung ventilation

Abstract

The insertion, checking and correct use of double lumen tubes or endobronchial blocking devices for bronchial isolation and one lung ventilation is a key anaesthetic skill. Competent and safe usage requires an appreciation of the mechanical principles underlying these techniques. Unfortunately, opportunities for trainees to gain sufficient experience with these techniques in the clinical setting are often limited both by the availability of appropriate cases and the reduction in trainees' working hours. We have noticed that when confronted with a double lumen endobronchial tube many trainees (and some consultants) do not have a logical system for clinically checking its location and correct function. We have produced a simple and cheap model, assembled from components readily found in most anaesthetic rooms, which can be used to demonstrate and test the mechanical principles underpinning one lung ventilation. The model can be used with both left and right-sided double lumen tubes and single lumen tube and bronchial blocker combinations, although it is not capable of simulating obstruction of the right upper lobe bronchus. Using sections of standard corrugated tubing from an anaesthetic breathing system with 22 mm connectors, a Y-connector from a circle system, two 1 litre anaesthetic reservoir bags, a self-inflating resuscitation bag and a tube clamp, we assembled the device shown in Fig. 8. We found the model valuable in demonstrating the principles of one lung ventilation to anaesthetic trainees, operating department practitioners and nurses working with patients undergoing thoracic surgery. Model trachea showing successful isolation and ventilation of the right ‘lung’ with a right-sided double lumen tube. If the model trachea is intubated with a single lumen tube it can be used for training in fibreoptic bronchoscope-guided bronchial blocker placement. With suitable manipulation of a double lumen tube in relation to the Y-connector, the model can be used to simulate a variety of tube misplacements including over-insertion (tracheal opening within the main bronchus), under-insertion (bronchial opening above the carina) and lateral transposition (such as a right double lumen tube into the left main bronchus) – either individually or in combination. If the ‘carinal’ component of the model is obscured with a drape, it can be used to develop and test anaesthetists' strategies for recognising and managing double lumen tube malposition.