From the Guidelines
If the dicrotic notch is visible during IABP augmentation, the balloon is inflating too late. The correct timing for intra-aortic balloon pump inflation should occur precisely at the dicrotic notch, which represents aortic valve closure at the end of systole. When inflation happens after the dicrotic notch appears, the balloon misses the optimal moment to augment coronary perfusion during early diastole. Proper IABP timing should completely obscure the dicrotic notch on the arterial waveform as the balloon inflation coincides with and replaces this feature. This late inflation reduces the effectiveness of diastolic augmentation, potentially compromising myocardial oxygen supply and the hemodynamic support the IABP is intended to provide. To correct this timing issue, the inflation point should be adjusted earlier to coincide with the dicrotic notch, ensuring maximal coronary perfusion and optimal cardiac support.
The management of intra-aortic balloon pump therapy is crucial in cardiac surgery, as highlighted in a study published in Critical Care in 2010 1. The study emphasizes the importance of proper timing and placement of the IABP to achieve optimal results. However, the most recent and highest quality study on this topic is not directly related to the specific question of IABP timing, but rather focuses on the overall management of cardiogenic shock, as seen in the 2021 study published in Circulation 1.
Key points to consider when managing IABP therapy include:
- The IABP should be inserted as soon as evidence points to possible cardiac dysfunction, preferably intraoperatively to avoid the excessive need of inotropic support.
- The IABP is contraindicated for patients with severe aortic insufficiency, and advanced peripheral and aortic vascular disease.
- Proper IABP timing is crucial to achieve optimal results, and the inflation point should be adjusted to coincide with the dicrotic notch.
In terms of morbidity, mortality, and quality of life, proper IABP timing is essential to ensure optimal cardiac support and reduce the risk of complications. As noted in the 2009 study published in the European Heart Journal 1, the IABP improves diastolic coronary and systemic blood flow, and reduces afterload and myocardial work, leading to improved myocardial and organ recovery after ST-segment elevation myocardial infarction. However, the 2021 study published in Circulation 1 highlights the importance of considering the overall management of cardiogenic shock, rather than just focusing on IABP timing.
Overall, proper IABP timing is crucial to achieve optimal results, and the inflation point should be adjusted to coincide with the dicrotic notch, ensuring maximal coronary perfusion and optimal cardiac support.
From the Research
IABP Augmentation and Dicrotic Notch Visibility
- The visibility of the dicrotic notch during IABP augmentation is an important indicator of the timing of balloon inflation.
- If the dicrotic notch is visible, it means that the balloon is inflating at the correct time, which is after the dicrotic notch [ 2 ].
- The dicrotic notch is a feature of the arterial blood pressure waveform that indicates the closure of the aortic valve [ 3 ].
- Inflation of the balloon after the dicrotic notch allows for optimal augmentation of diastolic coronary perfusion pressure and reduction of systolic afterload [ 4 ].
Timing of Balloon Inflation
- The timing of balloon inflation is critical for effective IABP augmentation.
- Inflation of the balloon too early or too late can reduce the effectiveness of IABP and may even cause harm [ 5 ].
- The use of algorithms that predict the dicrotic notch can help to optimize the timing of balloon inflation [ 2 ].
- These algorithms can be used to control the inflation and deflation of the balloon in real-time, allowing for optimal augmentation of cardiac output [ 5 ].