Abstract
Whilst cannulating the aorta using an adjustable ‘position stop’ cannula it is possible to introduce the ‘position stop’ within the aorta. It is then possible for the ‘position stop’ to embolise. A technique to prevent this potentially fatal complication is described.
Complications associated with aortic cannulation for bypass although rare are well recognised. These include rupture, dissection and pseudoaneurysm formation [1,2],. Although uncommon they are associated with a high risk of mortality [3]. Cannulation is a skill that is normally acquired relatively early in a trainee surgeons’ career. Consequently the surgeon cannulating the aorta maybe relatively junior. On two separate occasions in my practice during the last three years trainee surgeons have initiated a potentially fatal complication from aortic cannulation that I have not previously seen.
A variety of aortic cannulae are commercially available including those with an adjustable ‘position stop.’ This rests against the external surface of the aorta following cannulation and determines the length of the intra aortic cannula. It is normally supplied in a standard position but can be adjusted when loosened with fingers or forceps. The more the ‘position stop’ is adjusted the looser it becomes. On two occasions the aortic cannula was so forcibly inserted that the ‘position’ stop was also introduced into the aortic lumen (Fig. 1A). The immediate intention of the cannulating surgeons was to withdraw the cannula. However, this was resisted as a withdrawal has the potential to dislodge the ‘position stop’ within the circulation (Fig. 1B). As it is not radio-opaque it would then become ‘lost’ within the arterial circulation. Its final position would only be revealed by the clinical manifestation of distal ischaemic damage within the brain, other organ or limb. Such a potentially fatal complication may be very simply prevented. The initial tendency to withdraw the cannula must first be suppressed. The aortic space within which the ‘position stop’ is located must then be isolated. This is easily achieved either by using a Satinski (partial) ‘top end’ clamp (Fig. 2) or by using two fingers appropriately positioned. The aortic cannula may then be withdrawn. In some cases the aortotomy might need to be extended and a new purse string inserted. If the ‘position stop’ has become dislodged then it is now safely contained within the isolated aorta. It cannot embolise from this site and can now be safely removed.
A – Aortic cannula inserted with ‘position stop’ within the aortic lumen. B – Potential embolisation of ‘position stop’ following withdrawal of the aortic cannula.
‘Position stop’ isolated within the aortic lumen using a ‘top end’ clamp.
