Robert E. Grady

Neurologic complications after placement of cerebrospinal fluid drainage catheters and needles in anesthetized patients: Implications for regional anesthesia

UNLABELLED Subarachnoid or epidural needle placement in an anesthetized patient is controversial because general anesthesia and muscle relaxation may mask neural trauma. However, placement of a needle or catheter in the subarachnoid space for the purpose of cerebral spinal fluid (CSF) drainage is frequently performed in anesthetized patients undergoing neurosurgery. The records from 530 consecutive transsphenoidal surgeries performed with lumbar CSF drainage were reviewed to determine the types of neurologic complications attributable to spinal drainage and their rates of occurrence. All patients were anesthetized during CSF drain placement. A 19-gauge malleable needle was placed in 473 (89%) patients. Subarachnoid catheters (20- or 16-gauge catheters placed via 18- or 14-gauge epidural needles, respectively) were placed in 17 (3%) patients. In 40 (8%) patients, the type of drain was unspecified. No new neurologic deficits attributable to spinal drain insertion were detected in the immediate postoperative period or within 1 yr of surgery. Thirteen patients developed postdural puncture headache (2.5%, exact 95% confidence interval 1.3%-4.2%); seven required epidural blood patch (1.3%, 0.5%-2.7%). The low incidence (0%, 0.0%-0.7%) of neurologic injury from spinal drain insertion in anesthetized patients from this study is similar to the incidence of neurologic complications historically reported for both CSF drain insertion and spinal anesthesia. IMPLICATIONS The performance of regional anesthesia in an anesthetized patient is controversial due to the possibility of unrecognized nerve injury. We report no cases of nerve injury caused by the placement of cerebrospinal fluid drainage needles and catheters in 530 anesthetized patients undergoing neurosurgery.

The Effects of Remifentanil on Epileptiform Discharges during Intraoperative Electrocorticography in Patients Undergoing Epilepsy Surgery

Summary:  Purpose: High‐dose i.v. opioids (e.g., alfentanil, 50 μg/kg bolus) are known to increase the intraoperative reading of epileptiform activity during epilepsy surgery (ES), thereby facilitating localization of the epileptogenic zone (i.e., the site of ictal onset and initial seizure propagation). However, this phenomenon has not been studied with remifentanil (i.e., a novel ultra‐short acting opioid). The purpose of the present study was to evaluate the effect of remifentanil on electrocorticography (ECoG) during ES.

Correlation of regional cerebral blood flow with ischemic electroencephalographic changes during sevoflurane-nitrous oxide anesthesia for carotid endarterectomy.

Background Carotid endarterectomy necessitates temporary unilateral carotid artery occlusion. Critical regional cerebral blood flow (rCBF) has been defined as the rCBF below which electroencephalographic (EEG) changes of ischemia occur. This study determined the rCBF50, the rCBF value at which 50% of patients will not demonstrate EEG evidence of cerebral ischemia with carotid cross‐clamping. Methods Fifty‐two patients undergoing elective carotid end‐arterectomy were administered 0.6–1.2% (0.3–0.6 minimum alveolar concentration) sevoflurane in 50% nitrous oxide (N2 O). A 16‐channel EEG was used for monitoring. The washout curves from intracarotid133 Xenon injections were used to calculate rCBF before and at the time of carotid occlusion by the half‐time (t1/2) technique. The quality of the EEG with respect to ischemia detection was assessed by an experienced electroencephalographer. Results Ischemic EEG changes developed in 5 of 52 patients within 3 min of carotid occlusion at rCBFs of 7, 8, 11, 11, and 13 ml [center dot] 100 g sup ‐1 [center dot] min sup ‐1. Logistic regression analysis was used to calculate an rCBF50 of 11.5 +/‐ 1.4 ml [center dot] 100 g sup ‐1 [center dot] min sup ‐1 for sevoflurane. The EEG signal demonstrated the necessary amplitude, frequency, and stability for the accurate detection of cerebral ischemia in all patients within the range of 0.6–1.2% sevoflurane in 50% N2 O. Conclusions The rCBF50 of 0.6–1.2% sevoflurane in 50% N2 O, as determined using logistic regression analysis, is 11.5 +/‐ 1.4 ml [center dot] 100 g sup ‐1 [center dot] min sup ‐1. Further, in patients anesthetized in this manner, ischemic EEG changes due to carotid occlusion were accurately and rapidly detected.

History of the Development of Antiemetic Guidelines at Mayo Clinic Rochester

This article describes the historic experience of the development of antiemetic guidelines for patients taking chemotherapy drugs at Mayo Clinic Rochester. The initial guidelines for the use of serotonin (5-hydroxytryptamine3) receptor antagonists for the prevention of chemotherapy-induced nausea and vomiting were developed in early 1995 and implemented in September 1995. In February 1997, the guidelines were reviewed and modified. In the spring of 1998, major changes were made based on new data from the literature and discussions with antiemetic authorities in the United States. These guidelines were implemented in July 1998. The guidelines were again reviewed and modified in December 1998. In addition, we compared costs associated with the 1997 guidelines and the December 1998 guidelines. The developed guidelines, utilizing clinically available agents, seem to provide high-quality patient care at a reasonable cost.

Aprotinin and deep hypothermic cardiopulmonary bypass with or without circulatory arrest for craniotomy

Deep hypothermic cardiopulmonary bypass with or without circulatory arrest has been used to facilitate the surgical repair of complex cerebrovascular lesions. The advantages of deep hypothermia have been tempered by the occurrence of coagulopathy that is associated with substantial morbidity and mortality. This study analyzed retrospectively the records of 13 patients who underwent cerebrovascular neurosurgery using deep hypothermic cardiopulmonary bypass with or without circulatory arrest during the period 1993 through 1999. All patients received the serine protease inhibitor aprotinin in an effort to avoid the development of a coagulopathy, defined as hemorrhage requiring reoperation. No patients developed postoperative intracranial hemorrhage. There was also no evidence of renal dysfunction, deep venous thrombosis, myocardial infarction, or pulmonary embolism. In conclusion, this study suggests that aprotinin may be beneficial to avoid the coagulopathy that is more likely to occur if deep hypothermic cardiopulmonary bypass with or without circulatory arrest is used for craniotomy without adverse effects on renal function or apparent thrombotic complications.

Intraoperative use of nitric oxide during intracranial aneurysm clipping in a patient with acute respiratory distress syndrome.

We describe a case of subarachnoid hemorrhage (SAH) complicated by acute respiratory distress syndrome (ARDS) and cerebral vasospasm. Inhaled nitric oxide (NO) was used to improve oxygenation, thereby facilitating cerebral aneurysm clipping.

An Unexpected Cause of Magnetic Resonance Image Distortion The Endotracheal Tube Pilot Balloon

ANESTHESIA services in the magnetic resonance imaging (MRI) suite are increasing and require that the anesthetic equipment used is adequate to ensure patient safety, is MRI compatible, and has a negligible effect on image quality. We report a case in which the MRI scan quality was noticeably degraded by an unsuspected but commonly used piece of anesthesia equipment, the pilot balloon valve of a conventional endotracheal tube.