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Page 10 of 14 Monaco et al. Vessel Plus 2023;7:23 https://dx.doi.org/10.20517/2574-1209.2023.113

own risks and complications. The risk of developing subarachnoid hemorrhage due to excessive loss of CSF
in a short time is lower with intermittent CSF drainage compared to continuous CSF drainage. Meningitis
(0.1%), subdural hematoma (1.7%), and intracranial hemorrhage (1.8%) are the most severe
[38]
complications , while subdural hematoma is associated with excessive CSF drainage and tearing of the
dural veins. A CSF pressure ≥ 10 mmHg is recommended in the absence of ischemia or to perform an
intermittent drainage of 10-20 mL/h with continuous systemic blood pressure monitoring. Patients with
cerebral atrophy, arteriovenous malformations, brain aneurysms, and a history of previous subdural
[39]
hematoma are particularly prone to developing cerebral hemorrhage .
Anemia
Monitoring of hemoglobin levels is particularly relevant as it directly affects DO . In situations where
2
cardiac output is suboptimal, maintaining maximum arterial oxygen saturation and hemoglobin levels
[40]
above 10 g/dL can be beneficial . The combination of bleeding, anemia, and hypotension can worsen SCI.
A decrease in the oxygen content of arterial blood (CaO ) leads to a reduction in the ratio of DO to oxygen
2
2
consumption (VO ) < 2. When DO falls below this threshold, VO becomes dependent on DO , leading to a
2
2
2
2
shift from aerobic to anaerobic metabolism, resulting in lactate production and metabolic acidosis. Thus, it
is crucial to manage bleeding by ensuring meticulous surgical hemostasis and employing viscoelastic tests.
Studies have shown that the use of rotational thromboelastometry significantly reduces the need for fresh
frozen plasma (FFP) administration. Reduced FFP usage is associated with less hemodilution and anemia,
[41]
which can help mitigate the negative effects on oxygen delivery and prevent further complications of SCI .
Hypothermia
Several experimental studies have demonstrated the protective effect of mild hypothermia on the prevention
of SCI by reducing both nerve tissue metabolism and the release of excitatory neurotransmitters . This
[42]
constitutes the pathophysiological rationale for the use of regional hypothermia during aortic clamping .
[43]
Cambria et al. report a protective effect of regional hypothermia of the spinal cord through epidural cooling
when it is used in combination with CSF drainage and intercostal artery repletion . Shimizu et al. confirm
[44]
these findings but propose the use of a double-lumen catheter inserted into the peridural space into which
cold saline is infused .The risk of inserting a catheter of significant size (16 gouges in diameter and 30 cm
[45]
in length) into the peridural space, together with disputed scientific evidence, has ultimately limited the use
of techniques for regional cooling of the medulla to local experience.

Intrathecal drugs
Intrathecal administration of different drugs has led to inconclusive results so far. Lima et al. reported that
in 330 patients undergoing TAAA surgery, the addition of 30 mg of papaverine 1% intrathecally 10 min
before aortic clamping exhibited neuroprotective effects . The rationale is its vasodilatory effect on the
[46]
arterial circulation, which would increase blood flow to the spinal cord. However, its short duration of
action and the risk of hypotension associated with possible systemic reabsorption have limited its use over
time. Other authors have proposed the use of naloxone, which would have a neuroprotective effect by
decreasing the level of endorphins released during SCI . In particular, Acher et al. observed a significant
[47]
reduction in SCI in the 49 patients in whom naloxone was used in conjunction with CSF drainage . Other
[47]
drugs such as calcium antagonists, N-methyl-d-aspartate, and edaravone were in animal models, but none
have provided results convincing enough to be implemented in clinical trials [48,49] .

CONCLUSION
TAAA repair carries substantial perioperative risks, with spinal cord ischemia being the most common
complication leading to paraplegia. Therefore, each scheduled surgery case requires thorough discussions
between surgeons and anesthesiologists to carefully weigh the benefits and risks specific to the patient’s