Intraoperative care for aortic surgery using circulatory arrest

Abstract

Abstract:The total circulatory arrest (CA) is necessary to achieve optimal surgical conditions in certain aortic pathologies, especially in those affecting the ascending aorta and aortic arch. During this procedure it is necessary to protect all the organs of ischemia, especially those of the central nervous system and for this purpose several strategies have been developed. The first and most important protective method is systemic hypothermia. The degree of hypothermia and the route of application have been evolving and currently tend to use moderate hypothermia (MH) (20.1-28 ℃) associated with unilateral or bilateral selective cerebral perfusion methods. In this way the neurological results are better, the interval of security is greater and the times of extracorporeal circulation are smaller. Even so, it is necessary to take into account that there is the possibility of ischemia in the lower part of the body, especially of the abdominal viscera and the spinal cord, therefore the time of circulatory stop should be limited and not to exceed 80 minutes. Evidence of possible neurological drug protection is very weak and only mannitol, magnesium, and statins can produce some benefit. Inhalational anesthetics and some intravenous seem to have advantages, but more studies would be needed to test their long-term benefit. Other important parameters to be monitored during these procedures are blood glucose, anemia and coagulation disorders and acid-base balance. The recommended monitoring is common in complex cardiovascular procedures and it is of special importance the neurological monitoring that can be performed with several techniques, although currently the most used are Bispectral Index (BIS) and Near-Infrared Spectroscopy (NIRS). It is also essential to monitor the temperature routinely at the nasopharyngeal and bladder level and it is important to control coagulation with rotational thromboelastometry (ROTEM).

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“…5,12,14,15,36,39 Catapano et al 39 analyzed that there is a positive association between high values of mean arterial pressure and neurological improvement in patients with spinal cord injury. Ullery et al 40 came to the same conclusion in patients who had undergone a correction of aortic aneurysm; they also added that the mean arterial pressure < 70 mm Hg is a risk factor for spinal cord ischemia. The goal is to keep the mean arterial pressure at least 80 mm Hg for a surgical procedure that produces spinal ischemia, such as an aorta-related procedure, and maintain this goal by suspending 24 to 72 hours, adding any hypertensive agent if necessary.…”

“…It should be noted that oxygen participates in the reactions of cell respiration and cell death, so that interruption of use is key to prevent the neuronal damage after the blood supply is suspended. 40 Hypothermia is neuroprotective as it seeks to reduce the rate of oxygen metabolism. 40 Hypothermia reduces intracellular enzyme activity by 6 to 7% per degree of temperature reduction; also, it reduces glutamate release or enhanced release of GABA, suppresses intracellular calcium intake, and decreases free radical generation to result in mitigation of harmful response of reperfusion.…”

Cerebral Protection Strategies and Stroke in Surgery for Acute Type A Aortic Dissection

“…An analysis of the German Registry for Acute Aortic Dissection Type A revealed that 50% of patients undergoing surgery for ATAAD received at least one neuroprotective drug, indicating a slight advantage for the use of steroids in terms of neurological outcomes [ 79 ]. However, further scientific evidence supporting the implementation of neuroprotective pharmacological treatment is low, while no significant benefit has been shown in larger clinical trials yet [ 80 ].…”

Early Onset of Postoperative Gastrointestinal Dysfunction Is Associated With Unfavorable Outcome in Cardiac Surgery: A Prospective Observational Study

“…This may be due to the hypothermic circulatory arrest, known to increase the risk of complications. 21,22 After elective aortic hemiarch reconstruction, a combined GI bleeding and ischemia rate of 3.3% to 3.9% was shown. 23 Likewise, the longer duration of surgery and longer time on ECC in the AGI ≥2 group can be attributed to the difference in types of surgery.…”