Giant cerebral aneurysm repair. Incorporating cardiopulmonary bypass and neurosurgery

Rapid Ventricular Pacing as a Safe Procedure for Clipping of Complex Ruptured and Unruptured Intracranial Aneurysms

Surgical treatment of intracranial aneurysm requires advanced technologies to achieve optimal results. Recently, rapid ventricular pacing (RVP) has been described to be an elegant technique that facilitates clip reconstruction of complex unruptured intracranial aneurysm (uIA). However, there is also a growing need for intraoperative tools to ensure safe clip reconstruction of complex ruptured intracranial aneurysm (rIA). We conducted a retrospective analysis of 17 patients who underwent RVP during surgical reconstruction of complex aneurysms. Nine patients had uIA while eight patients underwent surgery for rIA suffering from consecutive subarachnoid hemorrhage (SAH). Hemodynamic data, critical events, laboratory results, and anesthesia-related complications were evaluated. No complications were reported concerning anesthesia induction and induction times were similar between patients exhibiting uIA or rIA (p = 0.08). RVP induced a significant decline of median arterial pressure (MAP) in both groups (p < 0.0001). However, median MAP before and after RVP was not different in both groups (uIA group: p = 0.27; rIA group: p = 0.18). Furthermore, high-sensitive Troponin T (hsTnT) levels were not increased after RVP in any group. One patient in the rIA group exhibited ventricular fibrillation and required cardiopulmonary resuscitation, but has presented with cardiac arrest due to SAH. Otherwise, no arrhythmias or complications occurred. In summary, our data suggest RVP to be feasible in surgery for ruptured intracranial aneurysms.

Deep Hypothermic Circulatory Arrest for Complex Cerebral Aneurysms: Lessons Learned

OBJECTIVE

Deep hypothermic circulatory arrest is a useful adjunct for treating complex aneurysms. Decreased cerebral metabolism and resultant ischemic tolerance create an environment suitable for devascularizing high-risk lesions. However, the advent of modern imaging modalities, innovative cerebral revascularization strategies, and the emergence of endovascular stenting and coiling limit the number of aneurysms requiring this surgical intervention. We present 66 patients with intracranial aneurysms who underwent surgical clipping under deep hypothermic arrest and attempt to identify patients well-suited for this procedure.

METHODS

This study was conducted during a 15-year period and examined patients with aneurysms of the anterior and posterior cerebral circulation. Demographics, aneurysm characteristics, and surgical factors were evaluated as predictors of functional outcome.

RESULTS

Patient age and the duration of cardiac arrest were independent predictors of early clinical outcome (P &lt; 0.05). Our experience suggests that the ideal patient is younger than 60 years old and harbors few medical comorbidities. Individuals with large aneurysms of the anterior communicating artery, internal carotid artery bifurcation, posterior inferior cerebellar artery, midbasilar, or vertebral arteries and with an absence of thrombosis and calcium may be most likely to experience favorable outcomes. Circulatory arrest should not exceed 30 minutes. Postoperative computed tomographic scanning and timely anesthetic emergence allow for early detection of hemorrhage. Complete dissection of the aneurysm before bypass and avoiding extreme hypothermia yield a low incidence of life-threatening postoperative hematomas.

CONCLUSION

Hypothermic circulatory arrest is a useful technique for neuroprotection during the clipping of complex cerebral aneurysms. This procedure, however, has several associated risks. Patient factors, pathoanatomic characteristics, and surgical parameters may be used to guide patient selection.

Detrimental effects of hypothermia: a systems analysis

Hypothermia influences body functions in many positive and negative ways. Hypothermia may be purposely induced during neurological or cardiac surgery for its cerebral protectant effects. However, hypothermia during the perioperative period is often detrimental, leading to increased bleeding and blood product utilization, as well as prolonged stays in the PACU. This article presents an overview of the physiology of temperature regulation and risk factors for the development of perioperative hypothermia. The effects of hypothermia on various body systems also are discussed and perioperative concerns explored.

Thermal regulation of patients during the perioperative period

Surgery patients often become hypothermic during surgical procedures. The body's thermostat, the hypothalamus, strives to maintain a normal temperature; however, when a patient's temperature drops too low, the thermoregulatory processes are suppressed, and hypothermia occurs. Cardiopulmonary bypass procedures use induced hypothermia; however, inadvertent hypothermia may occur in many other surgical procedures during which the body temperature is not systematically monitored and regulated. Hypothermia may cause complications such as protein catabolism, hypokalemia, and changes in glucose metabolism and glomerular filtration. Nursing interventions used intraoperatively to maintain a normothermic state include applying warm and temperature regulating blankets, decreasing the amount of skin exposure, and warming operating rooms.