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✓ The intrasellar pressure has been studied in a consecutive series of 24 patients undergoing transsphenoidal surgery for pituitary adenoma. The mean intrasellar pressure for the group was 23 ± 2.5 mm Hg (± standard error of the mean), with a mean pulse pressure of 3.5 ± 1 mm Hg. The waveform partly resembled the arterial configuration. The results are correlated with the radiological and endocrinological features of the tumors. A hypothesis is proposed to explain the mechanism of hyperprolactinemia associated with the pituitary stalk compression syndrome.

✓ The response of cerebral blood flow (CBF) to drug-induced hypotension was measured in 20 patients who underwent craniotomy for clipping of a cerebral aneurysm following subarachnoid hemorrhage. A modified intravenous xenon-133 injection technique was used to monitor CBF. In 15 patients, CBF increased significantly with hypotension, and only one developed a late neurological deficit. In five patients, CBF fell with halothane-induced hypotension, and four developed delayed neurological deficits. Measurement of the intraoperative CBF response to halothane-induced hypotension may reveal those patients at greatest risk of developing late neurological deficits and who require more intensive postoperative monitoring and early use of the induced hypertension technique.

✓ The transient hyperemic response test has been shown to provide an index of cerebral autoregulation in healthy individuals and in patients who have suffered a subarachnoid hemorrhage. In this study, the test was applied to patients who had received a severe head injury, and the value of the test was assessed by comparing its result with the individual's clinical condition (Glasgow Coma Scale [GCS] score), cerebral perfusion pressure (CPP), transcranial Doppler wave form—derived index for cerebral autoregulation (relationship between the CPP and the middle cerebral artery flow velocity), and outcome (Glasgow Outcome Scale [GOS] score).

Forty-seven patients, aged 16 to 63 years, with head injuries were included in the study. Signals of intracranial pressure, arterial blood pressure, flow velocity, and cortical microcirculatory flux were digitized and recorded for a period of 30 minutes using special computer software. Two carotid compressions were performed at the beginning of each recording. The transient hyperemic response ratio (THRR: the ratio of the hyperemic flow velocity recorded after carotid release and the precompression baseline flow velocity) was calculated, as was the correlation coefficient Sx used to describe the relationship between slow fluctuations in the systolic flow velocity and CPP throughout the period of recording.

No significant changes in CPP were found during compression. There was a significant correlation between the THRR and the Sx (r = 0.49, p < 0.0001). The hyperemic response proved to be lower in patients who exhibited a poor clinical grade at presentation (GCS scores < 6, p = 0.01) and lower in patients achieving a poor outcome (GOS scores of 3, 4, and 5, p = 0.003). Loss of postcompression hyperemia occurred when the CPP fell below 50 mm Hg.

The carotid compression test provides a simple index of cerebral autoregulation that is relevant to the clinical condition and outcome of the severely head injured patient.

✓ The authors describe a simple technique that reduces the incidence of retained ventricular catheters and minimizes the risk of life-threatening intraventricular hemorrhage during the removal of an obstructed, adherent ventricular catheter in patients with hydrocephalus. The technique requires no special equipment and has been successfully used, without complications, in a prospective series of 12 patients with 13 blocked, adherent ventricular catheters.

Object. The aim of this study was to determine the safety and efficacy of prophylactic high-dose intravenous aprotinin in reducing intraoperative blood loss in the neurosurgical population.

Methods. A randomized, double-blind, placebo-controlled trial was conducted in parallel groups in two regional neurosurgical departments. One hundred patients with a preoperative diagnosis of intracranial meningioma or vestibular schwannoma subsequently confirmed on histological studies were included. All patients were older than 18 years of age, pregnancy had been excluded, there was no history of bleeding diathesis, no previous exposure to aprotinin, and no ingestion of antiplatelet or anticoagulant medications within the 2 weeks preceding surgery. Aprotinin was administered in doses of 30,000 kallikrein-inhibiting units (KIU)/kg body weight on induction of anesthesia and was continued as an infusion of 10,000 KIU/kg/hr until surgery was complete, or for a maximum of 8 hours. Intraoperative blood loss, blood transfusion, the Glasgow Outcome Scale score, and the Index of Independence were measured, and screening for deep vein thrombosis and the Mini-Mental State Examination were performed.

Conclusions. Intraoperative blood loss was reduced from 1014 ml (geometric mean) to 508 ml (p = 0.028). Although this study was not designed to evaluate the need for blood transfusion, 37 U of blood was used in 11 patients in the aprotinin group and 58 U in 13 patients in the placebo group (not significant). There were no significant differences in postoperative thrombotic risk or other outcome measures between treatment groups. Aprotinin therefore can be safely used to reduce intraoperative blood loss in patients who are not receiving anticoagulation therapy.