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The BTS guidelines advocate aspiration as a first line procedure in patients with dyspnoea or complete collapse.1 Despite being common practice, there is no specifically designed equipment widely used for this procedure. The BTS guidelines suggest assembling equipment from a cannula, three way tap, and 50 ml syringe. The assimilation and use of equipment not designed for chest aspiration often leads to a prolonged and cumbersome procedure with the following inherent problems:
blind insertion of a sharp needle into the chest cavity risks damage to thoracic and upper abdominal viscera;
intravenous cannulae are designed to facilitate the flow of fluid and are therefore relatively short; as a result, some fail to traverse the chest walls of larger patients;
the thin plastic sheath is prone to damage as it passes through the chest wall;
kinking of the plastic sheath outside of the patient during use;
the equipment is cumbersome and time consuming to use;
the BTS guidelines suggest the removal of a maximum of 2.5 l (that is, 50 × 50 ml syringes).
We have used a Verres needle adapted with a one way valve designed to treat uncomplicated spontaneous pneumothorax and to overcome the shortfalls of the method of aspiration advocated by the BTS guidelines. We used pre-production equipment provided by Rocket Medical plc. A Verres needle, normally used to establish a pneumoperitoneum in laparoscopic surgery, is used to insert the cannula. It has a spring loaded blunt tip that retracts into the needle upon pressure while passing through the thoracic wall. On entering the pleural cavity the spring loaded tip rapidly protrudes, shielding the needle and preventing visceral damage. At this point there is a palpable and audible click which indicates that the needle has traversed the thoracic wall. The sheath is advanced over the Verres needle. It is thicker than those of intravenous cannulae and thus resists damage from the chest wall and external kinking. The Verres needle is then removed.
Rather than aspirating air, the patient is encouraged to expire against gentle resistance. This raises intrathoracic pressure, forcing air from the pneumothorax via the cannula. Due to the one way valve, air cannot return. Furthermore, the one way valve has been adapted to whistle when air passes through it, so once the pneumothorax has resolved there is no whistling. At this point a check x ray is indicated. Conversely, an air leak will be indicated by continuous whistling.
We have used this equipment several times with no complication and describe a typical example of its use. A 23 year old man with a primary spontaneous pneumothorax fulfilled the BTS criteria for simple aspiration. With patient consent the Verres needle was introduced under local anaesthesia into the fifth intercostal space in the anterior axillary line. The click as the blunt tip of the Verres needle sprung forward indicated that the drain was in the pleural cavity. The patient was encouraged to expire against gentle resistance. On expiration the drain whistled. After 5 minutes the whistling stopped. A check x ray was taken which showed complete resolution of the pneumothorax. The patient was discharged and a review with x ray 3 and 10 days following the procedure revealed no complication or recurrence of the pneumothorax.
Other devices are available which detect placement of cannulae in the pleural space. The Tru-Close Thoracic Vent (Davis and Geck, USA) is an aspiration device comprising, in part, an external diaphragm that indicates pressure change upon entering the pleural cavity. This device does not have a mechanism to shield the needle tip and, despite the advantage of the diaphragm indicating intrapleural placement, there has been a case report of bronchopleural fistula following its use in a patient with chest wall adhesions.2 While no device can ensure that damage to lung tissue does not occur during this blind procedure, the Verres needle affords more protection than other established techniques. Despite limited experience with this device, we found it was simple to prepare and use and intrapleural placement was easy to recognise. Furthermore, it overcame the disadvantages that are associated with the widely used method advocated by the BTS.
The product becomes commercially available in March 2004 at an approximate price of £30 per unit.
None of the authors has links with Rocket Medical plc and they have received no funding, payment, or rewards from the company.
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