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Biomedical subjects

E L Bloomfield

Publications and source records attributed to E L Bloomfield.

11 recordsLinked to original sources
PubMed1998

The influence of scalp infiltration with bupivacaine on hemodynamics and postoperative pain in adult patients undergoing craniotomy.

UNLABELLED: After craniotomy, hypertension may contribute to intracerebral hemorrhage. We studied whether scalp infiltration with bupivacaine during craniotomy reduces postoperative pain and hypertension. In a double-blind fashion, 36 adult patients (ASA physical status II or III) undergoing elective craniotomy were randomly assigned to receive scalp infiltration with either bupivacaine (0.25%) and epinephrine (1:200,000) or saline/ epinephrine (1:200,000) for skeletal fixation, skin incision, and wound closure. Heart rate (HR) and mean arterial pressure (MAP) were measured after anesthesia induction, after skull-pin insertion, after scalp infiltration, during dural closure, during skin closure, on admission to postanesthesia care unit (PACU), and 1 h after admission. Visual analog pain scores were recorded in the PACU. MAP was significantly greater in the saline group at scalp infiltration. HR was significantly faster in the saline group at dural and skin closure. The bupivacaine group reported significantly less pain than the saline group at PACU admission and 1 h after admission. Pain scores did not correlate with hemodynamic measurements. We conclude that scalp infiltration with 0.25% bupivacaine with 1:200,000 epinephrine blunts certain intraoperative hemodynamic responses and reduces postoperative pain but has no effect on postoperative hemodynamics. IMPLICATIONS: We sought to evaluate whether scalp infiltration with bupivacaine and epinephrine at the beginning and end of craniotomy would afford more intra- and postoperative hemodynamic stability and influence immediate postoperative pain. We found that intraoperative hemodynamics were not influenced greatly; however, craniotomy patients do have significant postoperative pain, which does not seem to have an influence on hemodynamics in the postanesthesia care unit.

Adolescent↗
PubMed1996

Cardiovascular collapse during anesthesia in a patient with preoperatively discontinued chronic MAO inhibitor therapy.

We describe a patient in whom long-term monoamine oxidase (MAO) inhibitor therapy was discontinued 20 days before surgery with general anesthesia. This patient developed severe perioperative hypotension after administration of 10 mg of bupivacaine through an epidural catheter, which was corrected only after potent vasopressor therapy. We attribute this hemodynamic instability to attenuation of this patient's sympathetic tone based on several mechanisms: (1) residual effect of long-term administration of MAO inhibitor that caused a decrease in the number of beta-adrenergic receptors (adrenergic subsensitivity due to receptor down-regulation), (2) recovered MAO activity causing effective degradation of sympathetic amines, and (3) combined attenuating effects of general and epidural anesthesia on sympathetic tone.

Aged↗
PubMed1996

Effect of cranial surgery and brain tumor size on emergence from anesthesia.

BACKGROUND: Knowing which neurosurgical patients are at risk for delayed awakening may lead to better utilization of intensive care resources and avoid the risk and cost of pharmacologic reversal and diagnostic tests. METHODS: The authors compared anesthetic emergence from complex spinal surgery (spine; n = 47) with that from craniotomy for supratentorial nonfrontal (n = 22), frontal (n = 34), or posterior fossa tumor (n = 28). A further comparison involved patients with small versus large (diameter > 30 mm, mass effect) tumors. The standardized anesthetic regimen consisted of induction with 2-4 mg/kg-1 thiopental and 1-2 micrograms/kg-1 sufentanil, followed by maintenance with nitrous oxide, 0.2-0.5 micrograms.kg-1.h-1 sufentanil and < or = 0.5% isoflurane. Sufentanil administration was terminated on dural or spinal muscle closure, isoflurane during skin closure, and nitrous oxide during dressing application. After discontinuing nitrous oxide, a minineurologic examination was performed every 15 min for 1 h, then hourly for 4 h and at 24 h. RESULTS: Craniotomy patients performed less well than spinal surgery patients on the minineurologic examination 15 and 30 min after discontinuing nitrous oxide. At 15 min, fewer patients with large (vs. small) tumors were oriented to time (58% vs. 87%; P < 0.01) or place (67% vs. 90%; P < 0.01). Forty-two percent of patients with large tumors still had an abnormal minineurologic examination score versus 15% of patients with small tumors. At 30 min, these values were 28% and 8%, respectively (P < 0.05). Seventy-one percent of patients with large tumors were oriented to time compared to 97% for small lesions (P < 0.01). Emergence from anesthesia was similar for spinal surgery patients and patients with small brain tumors. CONCLUSION: Patients undergoing craniotomy for large intracranial mass lesions awaken more slowly than patients after spinal surgery or craniotomy for small brain tumor.

Anesthesia↗
PubMed1996

Analysis of catecholamine and vasoactive peptide release in intracranial arterial venous malformations.

Craniotomy for resection of cerebral arterial venous malformation has been associated with postoperative hypertension, which necessitates administration of large doses of antihypertensive medications to control blood pressure. Controlling blood pressure is essential because hypertensive episodes can lead to postoperative cerebral hemorrhage with increases in morbidity and mortality. We measured vasoactive peptide and catecholamine release in 13 patients who underwent resection of an arterial venous malformation and in a control group of 6 patients who presented for clipping of unruptured cerebral aneurysms. Plasma renin activity, angiotensin I and II, vasopressin, aldosterone, epinephrine, and norepinephrine levels were measured intraoperatively and for 36 h postoperatively. Analysis of variance was used to assess sample and group effects. A significant interaction between sample and groups was found for norepinephrine (p < 0.001) and renin (p = 0.002). Our data suggest that elevated plasma renin and norepinephrine levels are in part responsible for postoperative hypertension in patients undergoing resection of arterial venous malformations. Blocking the release of these hormones may help control blood pressure after surgery for removal of arterial venous malformations.

Adult↗
PubMed1993

Intravenous sedation for MR imaging of the brain and spine in children: pentobarbital versus propofol.

The authors present a prospective study of single-agent pediatric sedation regimens for patients older than 2 years of age undergoing magnetic resonance (MR) imaging of the brain and spine. Thirty patients underwent MR imaging after intravenous administration of pentobarbital in successive boluses of 2.5 mg/kg to a maximum of 7.5 mg/kg. Thirty-one patients received an intravenous bolus followed by continuous infusion of propofol. The dosage schedule for propofol was 2 mg/kg (with supplemental 1 mg/kg boluses) followed by continuous infusion of 6 mg/kg per hour. There was no significant difference in the physiologic response to sedation between the two groups, although the magnitude of the drop in pulse was significantly greater in the group receiving propofol. Three patients receiving propofol experienced transient decreases in oxygen saturation, at variable times over the course of the procedure. However, patients recovered significantly faster from sedation with propofol. While propofol may represent a viable alternative to pentobarbital in selected patients, propofol requires constant physician supervision and meticulous technique.

Brain↗
PubMed1993

Vancomycin does not enhance hypotension under anesthesia.

The rapid administration of vancomycin is associated with flushing and hypotension, a consequence of histamine release. The manufacturer discourages administering vancomycin to anesthetized patients, stating that vancomycin aggravates the hypotensive effects of anesthetics. To test this, we randomly assigned 36 adults (ASA classes I through III) to one of two groups: preinduction (Preind, n = 19) and postinduction (Postind, n = 17). Both groups received two different infusions: vancomycin (1 g/250 mL normal saline) and saline (250 mL normal saline) over 30-60 min. The Preind group received vancomycin before anesthesia was induced and saline was administered immediately after anesthesia was induced; for the Postind group, this order was reversed. This was done in a double-blind fashion. The anesthetic induction was standardized by the intravenous administration of thiopental and vecuronium and anesthetic maintenance by inhalation of nitrous oxide and enflurane. End-tidal enflurane, heart rate (HR), and blood pressure (BP) were measured every 3 min. Independent (unpaired) t-test was used in data analysis. The groups did not differ significantly. We conclude that vancomycin infusion may be given under anesthesia without significant adverse hemodynamic consequences if administered over a 30-60 min period of time.

Adult↗
PubMed1992

The incidence of postoperative nausea and vomiting: a retrospective comparison of alfentanil versus sufentanil.

Postoperative nausea and vomiting have been associated with the use of intravenous narcotics, and nitrous oxide may worsen the emetic effects of narcotics. Alfentanil and sufentanil are two synthetic derivatives of fentanyl; alfentanil has a shorter wake-up time than fentanyl, and sufentanil is equivalent to fentanyl. In order to study comparative emetic properties of these two drugs, patients in two different cities were randomly allocated to two different groups and retrospectively compared. Group I received sufentanil N2O/O2 with 0.25% isoflurane. Group II received alfentanil N2O/O2 with 0.25% isoflurane. With group I, the overall incidence of nausea was 31% and of vomiting was 6.2%. For group II, the overall rate for nausea was 38.2% and 8.8% for vomiting. Statistically, there was no significant difference in nausea or vomiting between groups.

Adolescent↗
PubMed1989

Extracerebral complications of head injury.

Numerous complications accompany CNS injury. Control of pulmonary, cardiovascular, gastrointestinal, metabolic, hematologic, and infectious complications is essential to ensure the best possible outcome for these seriously injured patients.

Brain Injuries↗