Anaesthesia outside the operating room

Anaesthesia for endovascular management of cerebral aneurysms

Subarachnoid haemorrhage due to rupture of cerebral aneurysms is a multisystem disease. Treatment of the condition in the past has relied on craniotomy and clipping of the aneurysm to prevent a recurrent haemorrhage. There is now emerging evidence to suggest that endovascular treatment of cerebral aneurysms may reduce the morbidity associated with open surgery. The anaesthetic management of interventional neuroradiology also creates new challenges due to the novel approach to treatment. Anaesthetists need to be familiar with this procedure and the management of potential complications. This review provides an overview such considerations.

Anesthesia for cerebral aneurysms: a comparison between interventional neuroradiology and surgery

PURPOSE

To review the anesthetic management of patients with cerebral aneurysms during treatment in the interventional neuroradiology (INR) suite compared with in the operating room.

METHODS

This was a retrospective chart review of 100 consecutive patients treated by endovascular coiling compared with 100 patients treated by surgical clipping of a cerebral aneurysm. Information compared and analyzed included demographics, pre-procedure medical history, neurological status including location and size of aneurysm, anesthetic management, complications and patient outcome. P < 0.05 was considered significant.

RESULTS

Patients in the INR group were older (54 +/- 15 vs 49 +/- 12 yr), had a greater incidence of pre-procedure cardiorespiratory problems (55 vs 34 patients) and had more aneurysms located in the posterior fossa (68 vs 11) (P < 0.05). General anesthesia was used in all except seven INR patients who received conscious sedation. There were some differences in the anesthetic agents and techniques. There was less monitoring of INR patients; temperature (33 vs 99 patients), intraarterial catheter (22 vs 100), central venous catheter (4 vs 78), and evoked potential monitoring (0 vs 100). There were no differences in the incidence of documented complications or in patient outcome.

CONCLUSION

There were some differences in the anesthetic management of patients undergoing endovascular treatment of a cerebral aneurysm compared with treatment in the operating room. The patients in the INR suite were sicker and somewhat older and they received less invasive monitoring, but the complication rate and outcome did not differ.

A new frontier: magnetic resonance imaging-operating room

Developments in technology have led to the merger of two distinct environments, that of magnetic resonance imaging and that of the operating room. The major advantage of this merger for neurosurgical procedures is the ability to perform real-time imaging to help guide surgery. This review discusses the role of the anesthesiologist in the planning and administration of safe anesthesia in this new and challenging environment.

Airway management in neuroanaesthesia

PURPOSE

Airway management in neurosurgical patients presents unique challenges to the anaesthetist. This review will consider specific approaches to numerous problems in airway management related to logistical, physiological and anatomical concerns. The goal is to provide a clinically oriented and practical discussion regarding issues of airway management in neurosurgical patients.

SOURCE

The recent literature has been reviewed regarding airway management options and related perioperative complications in the neurosurgical population. This is interlaced with approaches to many of the problems and their solutions based on experience gained in a very busy university neurosurgical practice over the past decade.

PRINCIPAL FINDINGS

Specific pathophysiological alterations in the neurosurgical patient influence the technique chosen for securing an airway. These relate to the presence of increased intracranial pressure, intracranial aneurysms or arteriovenous malformations. Other important disorders influencing airway management include severe coronary artery disease, acromegaly and congenital airway difficulties. Stereotactic neurosurgery and conscious sedation for various neurosurgical procedures also provide unique challenges. There are other considerations unique to the neurosurgical patient such as intra-and postoperative airway obstruction and the timing of postoperative extubation.

CONCLUSION

The demands for airway management in neuroanaesthesia require expertise in the various modes of securing the airway while considering the patient's physiological requirements as well as the unique surgical demands.

Anaesthesia for cardioversion

Cardioversion is a minor procedure requiring sedation and analgesia. However, it is often performed out-of-hours in remote sites by inexperienced anaesthetists. An understanding is required both of the pathophysiology underlying cardiac arrhythmias and of the technical side of defibrillation equipment, including electrical safety. Patients should have their coagulation status and electrolyte balance checked prior to the procedure to reduce the likelihood of complications. Almost all the available anaesthetic agents have been used for cardioversion in the past, with varying degrees of success. The anaesthetic agent chosen for patients undergoing cardioversion must provide analgesia and sedation, cause the least cardiovascular compromise possible and still enable rapid recovery. Propofol may be the closest anaesthetic agent to this ideal currently available, although careful titration of any agent chosen is also important. Cardioversion may be performed as an emergency, including in the pregnant patient, providing safe anaesthetic practice is followed.