Deep hypothermic circulatory arrest
Deep hypothermic circulatory arrest (DHCA) is a surgical technique that involves cooling the body of the patient and stopping blood circulation. It is used in cardiac surgery to allow operation on the aortic arch and in neurosurgery to repair some brain aneurysms.
The procedure requires keeping the patient in a state of hibernation at 12–18 °C with no breathing, heartbeat, or brain activity for up to one hour. Blood is drained from the body to eliminate blood pressure. The patient is considered clinically dead during the operation.
The benefits of hypothermic circulatory arrest are derived from the effects of lowering the rate of cellular metabolisms. The lowered metabolism can lower mitochondrial damage and apoptosis.
"Most patients tolerate 30 min of DHCA without significant neurological dysfunction, but when this is extended to longer than 40 min, there is a marked increase in the incidence of brain injury. Above 60 min, the majority of patients will suffer irreversible brain injury, although there are still a small number of patients who can tolerate this. Longer periods of DHCA are tolerated in neonates and infants compared with adults."
"Surgical management of giant cerebral aneurysms remains a major technical challenge for modern neurosurgeons. Endovascular approaches for giant aneurysms does not provide an acceptable alternative to direct surgical approaches. The use of deep hypothermic circulatory arrest as an adjunct during clipping of complex giant aneurysms shows promise as a treatment for otherwise incurable lesions. Patient selection and techniques of circulatory arrest surgery are discussed".
- Nolan, J., Morley, P., & Vanden Hoek, T. (2003). Therapeutic hypothermia after cardiac arrest: An advisory statement by the advanced support task force of the international liaison committee on resuscitation. Circulation, (108), 118-121. doi: doi: 10.1161/01.CIR.0000079019.02601.90
- Conolly, S; Arrowsmith, JE; Klein, AA (2010). "Deep hypothermic circulatory arrest". Continuing Education in Anaesthesia, Critical Care & Pain 10 (5): 138–142. doi:10.1093/bjaceaccp/mkq024.
- Connolly ES, Solomon RA (1998). "Hypothermic cardiac standstill for cerebral aneurysm surgery". Neurosurgery Clinics of North America 9 (4): 681–95. PMID 9738100.