S. Pervaiz Butt et al.: J Extra Corpor Technol 2025, 57, 82 – 88 85
Figure 5. Pie chart showing use of Cerebral saturation across Pakistan.
Table 1. Survey questions.
1 Do you routinely employ a bubble detector during cardiopulmonary bypass procedures? 2 Do you regularly utilize a level detector during cardiopulmonary bypass procedures? 3 Do you incorporate an arterial filter into your cardiopulmonary bypass circuit? 4 Do you monitor continuous inline venous saturation during cardiopulmonary bypass procedures? 5 Do you employ cerebral saturation monitoring during cardiopulmonary bypass?
Table 2. Survey results.
Question |
Safety device |
Yes |
No |
Conditional |
1 |
Bubble detector |
71.2 % |
27.3 % |
1.5 % – only if available |
2 |
Level detector |
69.7 % |
30.3 % |
|
3 |
Arterial filter |
33.3 % |
59.1 % |
Some use integrated arterial filters Some depending on availability |
4 |
Continuous venous saturation monitoring |
25.8 % |
72.7 % |
Some have no availability of disposables |
5 |
Cerebral saturation monitoring |
23.1 % |
72.3 % |
Some use in selective cases of carotid stenosis Some when disposables were available |
unnoticed and air is pumped into the patient rendering initiation of a gross air protocol.
Also keeping a minimal level in the reservoir which is often recommended by each manufacturer helps prevent turbulent flow and GME from forming when running at low levels, a level alarm can help avoid and minimise these problems. 20 individuals stated they do not use level alarms in their centre. When looking at risk and reward in such a scenario, the risk to the patient can be potentially huge at the cost of a small alarm device.
Air micro-embolism reportedly occurs despite arterial filters of the cardiopulmonary bypass( CPB) circuit. Neurological complications occurring after open-heart surgery, which range from 1 to 6 % for stroke and up to 76 % for silent brain micro-infarcts or micro-bleeds. A relationship between air micro-embolism and cognitive decline affecting a variable percentage of patients after open-heart surgery has also been described. Gaseous microemboli may be one contributing factors to a multifactorial problem. Microemboli have been proven to be dangerous in experimental and clinical situations without any other confounding factors so awareness and prevention will certainly benefit patients. Putthetu et al did a study using an ultrasonic bubble counter( BCC300, Gampt) during bypass surgery in 10 CABG patients, and found that bubbles and air were detected throughout the bypass procedure. A vast majority of these are filtered through the oxygenator and number of bubbles decreased after the arterial filter. They found up to 2773 nl of total air going through their circuit in one procedure, up to 3424 bubbles detected in another procedure and bubbles larger than 1 mm detected. It was found that manipulations of the opened heart and arteries via direct blood-air contact, and manipulations on components of the CBP circuit are a major source of air in the CPB circuit [ 3 ].
Chung et al did a study where air volumes were measured in the middle cerebral artery territories using transcranial Doppler and found surgical manipulations, generated air bubbles in the brain [ 4 ], and Borger et al found a difference in neuropsychological outcome when comparing patients who underwent surgery with less than 10 perfusionist interventions versus those with 10 or more [ 5 ].
Although more evidence is needed to assess the clinical affects these microemboli have, evidence of microemboli created in surgery is still apparent. The growing use of low prime circuits to reduce haemodilution and systemic inflammatory response often now also see the use of vacuum assist devices whicharealsoknowntoproduceGME [ 6 ]. The use of Arterial filters can reduce systemic inflammatory responses or other neurological complications by filtering these embolis mentioned. While their use is relatively widespread, there exists variability, with some perfusionists using integrated filters