Neurophysiologic monitoring to assure delivery of retrograde cerebral perfusion.

BACKGROUND: Patients undergoing complex aortic procedures performed with deep hypothermia and circulatory arrest have a significant risk of an adverse neurologic event when the arrest period is prolonged. Retrograde cerebral perfusion appears to improve cerebral protection, although collapsed cortical veins or functional jugular venous valves may restrict flow at the frequently recommended maximum pressure of 25 mm Hg. Therefore, the purpose of this study was to demonstrate the benefit of multimodality neurophysiologic monitoring in assuring delivery of retrograde cerebral perfusion. METHODS: Electroencephalography, cerebral blood flow velocity, and regional cerebral venous oxygen saturation were used to quantify the intraoperative neurophysiologic changes accompanying retrograde cerebral perfusion. The magnitude of changes was compared with those previously observed during arrest without retrograde cerebral perfusion. RESULTS: Thirty patients underwent complex aortic procedures necessitating circulatory arrest, 22 with retrograde cerebral perfusion. The mean retrograde perfusion pressure of 40 mm Hg (30 to 49 mm Hg, 95% confidence interval) and flow rate of 1.2 L/min (0.9 to 1.6 L/min) necessary to achieve documented retrograde cerebral perfusion was much higher than previously recommended. During both retrograde cerebral perfusion and rewarming, cerebral oximetric monitoring guided adjustments in perfusion parameters to limit the rate of desaturation to 0.4% per minute (0.3% to 0.6%). With retrograde cerebral perfusion there was a rapid (1) recovery of electroencephalographic activity during rewarming (21 minutes [range 16 to 26 minutes]) and (2) return of consciousness after the operation (81% [58% to 95%, 95% confidence interval] awake by 12 hours). There was no transcranial Doppler evidence of cerebral edema with retrograde cerebral perfusion. Two neurologic complications occurred in the 22 patients managed with retrograde cerebral perfusion and one in the eight patients managed with arrest only. CONCLUSIONS: Multimodality neurologic monitoring assured optimal brain cooling and bihemispheric delivery of retrograde cerebral perfusion. Necessary retrograde pressure and flow were often higher than values previously reported. Avoidance of profound cerebral venous oxygen desaturation during retrograde cerebral perfusion and rewarming was associated with rapid recovery of neurologic function.

Changes in plasma potassium and neuromuscular blockade following suxamethonium in patients pre-treated with terbutaline.

Plasma potassium, heart rate, systolic and diastolic blood pressure were measured in adult surgical patients pre-treated with either terbutaline 1.25 mg (n = 10) or normal saline (n = 10) prior to and during general anaesthesia which included suxamethonium 1 mg kg-1. Neuromuscular blockade was then measured using a train-of-four technique. Plasma potassium was significantly lower before and during general anaesthesia in those patients who had received terbutaline but the rise following suxamethonium (measured at 1, 3, 5, 7, 10, 12, 15, 30 and 180 min after suxamethonium) was similar in both groups. Heart rate increased significantly in the treatment group both over time and compared to the control group. Onset time to maximum neuromuscular blockade and duration of blockade was shorter in the terbutaline-treated group.

Operating room management: the role of the anesthesiologist.

Operating room management structures and interrelationships both within the operating suite and with other departments in the hospital can be extremely complex. Several different professional and support groups are represented that often have infrastructures of their own that may compete or conflict with the operating room's management hierarchy. Often, there really is little actual management of the operating suite as an entity. Because the units must interact effectively to provide a high level of patient care, it is important that areas of conflict be resolved. Many problems can be averted by implementation of specific policies and procedures, after appropriate action by the medical staff outlining operating room goals and objectives, and the establishment of realistic lines of authority and communication. More important than the actual structure of the management components in developing an efficient and successful operating room is the ability of key management personnel to understand the dynamics of people and situations as they evolve. Management must also continually monitor and objectively evaluate the system so that areas of deficiency of conflict may be identified and policies or procedures adapted to adequately meet the changing needs of staff and patients. Anesthesiologists are in unique positions to deal with many of these problems and should play an active role in their resolution. As physicians and consultants, we have an understanding of the burden faced by surgeons relative to patient care. Because the majority of our working time is spent in the operating room, we have an opportunity to develop an effective working relationship with nursing staff.(ABSTRACT TRUNCATED AT 250 WORDS)