Ronald J. Faust

Venous air embolism in sitting and supine patients undergoing vestibular schwannoma resection.

OBJECTIVE This study retrospectively compares the incidence of venous air embolism (VAE) detection and morbidity in the sitting and supine positions. All patients underwent vestibular schwannoma resection via the retrosigmoid approach by a single surgical team. METHODS A total of 432 consecutive operations were reviewed, 222 of which were performed with the patients in the sitting position and 210 of which were performed with the patients in the supine position. Charts were reviewed for evidence of intraoperative VAE, intraoperative hypotension secondary to VAE, postoperative morbidity related to VAE, and other variables to compare the groups. RESULTS This study demonstrated a 28% incidence of VAE detection when patients were in the sitting position compared to a 5% incidence of VAE detection when patients were in the supine position (P < 0.0001). Intraoperative hypotension secondary to VAE was noted in 1.8% of the sitting patients and 1.4% of the supine patients (P=0.72, no significant difference). Postoperative morbidity caused by VAE was noted in one sitting patient (0.5%) (pulmonary edema) and in no supine patients (P=0.48, no significant difference). Blood loss was slightly greater in the supine group, and operative times were similar in both groups, despite that the average tumor size of patients operated on in the sitting position was 2.8 cm versus 2.2 cm in the supine group (P < 0.0001). CONCLUSION Our results indicate that although there is a higher incidence of VAE detection in sitting patients, the morbidity is not statistically greater. We conclude that because morbidity from VAE is similar in either position, patient positioning should be based on surgical team preference.

Current transfusion practices of members of the american society of anesthesiologists: a survey.

Background The last published survey of transfusion practices among members of the American Society of Anesthesiologists (ASA) was conducted in 1981. The ASA Committee on Transfusion Medicine conducted a new transfusion survey in 2002. Methods The survey was mailed to 2,500 randomly selected active ASA members. The previous survey was modified to incorporate questions based on the ASA Practice Guidelines for Blood Component Therapy. The chi-square test was used for comparisons. Two-tailed P values of 0.05 or less were considered as nonchance differences. Results A total of 862 survey responses were completed by anesthesiologists who provided or directly supervised anesthesia for patients who may have required transfusion. In a given week, 62% rarely or never transfused 3 or more units of blood to the same patient. The percentage of anesthesiologists who responded that it is never or rarely (1% or less of the time) necessary to cancel elective surgery because of unavailability of blood products was 96% in 2002. In 1981, 92% responded that it was rarely necessary, and 8% said that it was occasionally necessary. The percentage of anesthesiologists who required patients undergoing elective surgery to have a hemoglobin concentration of at least 10 g/dl decreased from 65% to 9% (P < 0.001). Before intraoperative erythrocyte transfusion, 89% of respondents performed hemoglobin or hematocrit determinations routinely or sometimes. Intraoperative autologous transfusion equipment availability increased from 39% to 95% (P < 0.001). Awareness of the ASA Guidelines was 72%. Conclusions Transfusion practices have changed considerably since 1981. Current transfusion practices are, in general, consistent with the ASA Guidelines.

The effect of desflurane and isoflurane on cerebrospinal fluid pressure in humans with supratentorial mass lesions

Desflurane, a new volatile anesthetic, produces cerebral vasodilation. The purpose of this study was to compare the effects of 1 MAC desflurane with those of isoflurane on cerebrospinal fluid pressure (CSFP) in patients with supratentorial mass lesions and a mass effect on computerized tomography (CT scan). Twenty adult patients undergoing craniotomy for removal of supratentorial mass lesions were studied. Ten patients received desflurane and 10 patients received isoflurane. Prior to induction of anesthesia, a radial artery catheter was inserted and a 19-G needle was inserted into the lumbar subarachnoid space to measure CSFP. Baseline arterial blood gases and CSFP were measured with the patient awake and unmedicated. Anesthesia was induced with thiopental (6-9 mg/kg) and muscle relaxation achieved with vecuronium (0.2 mg/kg). The lungs of all patients were hyperventilated to achieve an arterial CO2 tension of 24-28 mmHg. Anesthesia was maintained with 1 MAC volatile anesthetic, either 7.0% desflurane or 1.2% isoflurane in an air:O2 mixture to maintain an inspired O2 fraction (FIO2) of 0.50. Patients were not administered any other anesthetic until the dura was incised. Mean arterial pressure was kept within 20% of the patients mean ward values with the use of esmolol or phenylephrine. CSFP, mean arterial pressure, end-tidal CO2 concentration (PETCO2), hemoglobin O2 saturation, and cerebral perfusion pressure were recorded with the patient awake, immediately postinduction with thiopental, postintubation, after institution of the volatile anesthetic, and every 5 min until the dura was incised. There was no difference in the mean (+/- SD) awake CSFP between the desflurane (11 +/- 4 mmHg) and the isoflurane (10 +/- 2 mmHg) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in red blood cell transfusion practice during the past two decades: a retrospective analysis, with the Mayo database, of adult patients undergoing major spine surgery

BACKGROUND: Others have reported significant changes in red blood cell (RBC) transfusion practice during the past two decades during knee, hip, prostate, and carotid surgery. Similar data for patients undergoing major spine surgery, however, are not available.

Sedation for Stereotactic Headframe Application: A Randomized Comparison of Two Techniques

A prospective, randomized study was performed in 87 patients to compare the safety, efficacy and dose requirements of two sedation techniques for stereotactic headframe application. Sedation administration and headframe application averaged 30 min. Fifty patients weighing 76 +/- 13 kg (mean +/- SD) received mean doses of 154 micrograms fentanyl plus 5.5 mg droperidol i.v. (FD group). An additional 37 patients weighing 76 +/- 19 kg received mean doses of 127 micrograms fentanyl plus 6.7 mg Valium (diazepam; FV group). Both treatments provided excellent hemodynamic stability and a low incidence of adverse side effects while providing adequate analgesia and sedation. The incidence of anesthetist-assessed patient anxiety and discomfort was more favorable in the FD group.

Blood Substitutes: What is the Target?

In this chapter, we provide an overview of who, what, when, where, and why surgical patients receive blood. This information is used to construct a picture of the issues that will have to be addressed prior to the informal, widespread use of blood substitutes in humans. These concepts also highlight the need for more epidemiologic and “ecologic” information related to the current use of red blood cells. It also appears reasonable to suggest that administrative barriers to autologous blood donation (in its several forms) be eliminated to the greatest possible extent, that increased efforts at the recruitment of volunteer donors be made, and finally that the efficacy and cost of acute perioperative normovolemic hemodilution be more thoroughly evaluated in a well-designed, large-scale clinical trial. By being aware of the issues raised in this review, it is hoped that clinicians, scientists, and regulators interested in the development of safe and effective blood substitutes will remain tightly focused on the appropriate “target”, so that development of a product with a high degree of utility is forthcoming.

Status of the Match in Anesthesiology: 1988

The majority of anesthesia program directors agreed 2 years ago to use the National Resident Matching Program (NRMP) as the mechanism for appointing senior medical students to second postgraduate year positions in anesthesiology. Eighty-seven applicants for the Mayo Clinic program were surveyed to measure the level of cooperation with the NRMP by programs and applicants. Low percentages of applicants reported pressures to sign contracts (22.4%) or make verbal commitments before February (32.8%). The frequency of these incidents was extremely low when considered in light of the number of applicant interviews reported by the applicants who responded. Nonparticipation in the match is a more important problem than infractions of NRMP rules.

Abstracts of scientific papers computers in anesthesia VII

S OF SCIENTIFIC PAPERS COMPUTERS IN ANESTHESIA VII October 21-24 Grand Canyon, Arizona Sponsored by Vanderbilt University School of Medicine Department of Anesthesiology Division of Continuing Medical Education and University of Iowa College of Medicine Department of Anesthesia