Search PubMed⌕ Search

Biomedical subjects

J E Cooke

Publications and source records attributed to J E Cooke.

At least 19 recordsLinked to original sources
PubMed1991

Electroencephalographic quantitation of opioid effect: comparative pharmacodynamics of fentanyl and sufentanil.

The authors compared the pharmacodynamics of sufentanil with those of fentanyl using the electroencephalogram (EEG) as a measure of opioid drug effect. Sixteen patients were given a rapid infusion of sufentanil (18.75 micrograms/min) during EEG recording. To quantitate the opioid-induced slowing of the EEG, the authors analyzed its power spectrum and calculated the spectral edge. An inhibitory sigmoid Emax model of the maximal decrease in spectral edge produced by the opioid related spectral edge values to serum concentrations of sufentanil. The resulting data for the pharmacodynamic parameters of sufentanil were compared with fentanyl parameters that were obtained by reanalysis from an identically conducted, previously published study. The half-time of blood-brain equilibration (T1/2Keo) was not statistically different between sufentanil and fentanyl (6.2 +/- 2.8 vs. 6.6 +/- 1.7 min, mean +/- SD, respectively). The intrinsic potency of sufentanil, as measured by the serum concentration needed to cause half the maximal EEG slowing (IC50), was 12-fold greater (0.68 +/- 0.31 ng/ml) than that of fentanyl (8.1 +/- 2.2 ng/ml). The second part of the study verified the hypothesis that administration of equipotent bolus doses would produce equal onset times. Bolus injections of either 125 micrograms of sufentanil or 1,250 micrograms of fentanyl were given during EEG recording. The time from injection to 50% maximal EEG slowing (T50) was calculated for each patient. The values for T50 for the two groups did not differ. The authors conclude that fentanyl and sufentanil have similar pharmacodynamic profiles, the former being 12 times more potent than the latter.

Adolescent↗
PubMed1991

Prevention of thromboembolic disease following total knee arthroplasty. Epidural versus general anesthesia.

Seventy-two patients were randomized into a prospective clinical trial to evaluate the effects of epidural (EA) versus general anesthesia (GA) on the incidence of thromboembolic disease (TED) following total knee arthroplasty (TKA). Males received aspirin 650 mg po bid and females low-dose warfarin daily to maintain the prothrombin time at 15 to 16 seconds for pharmacologic prophylaxis against TED. Thirty-four patients had EA and 38 GA for their primary TKA. Contrast venography and ventilation-perfusion scanning were performed on the sixth, seventh, and eighth postoperative days, and these were interpreted in a blinded fashion. The mean age of the 45 males and 27 females was 64 years (range, 42-84 years). There were no significant differences between the two groups with respect to hematocrit, operative time, blood loss, number of units transfused, or hospital stay. Twelve of the 34 patients (35%) receiving an EA and 10 of the 38 patients (26%) receiving GA developed TED, an overall incidence of 31% (p greater than 0.05) Fifty-three percent of the clots were located in the popliteal vein above the trifurcation or more proximal. However, the incidence of proximal vein thrombosis was significantly less in patients receiving an EA (46%) rather than a GA (64%). The incidence and distribution of clots was not affected by the type of pharmacologic prophylaxis, gender, or use of methylmethacrylate. Ten percent of the patients had a positive scan by strict criteria and were thought to have a pulmonary embolism (PE). In patients with a femoral vein clot, the incidence of PE was 67%. One bleeding complication occurred in a patient who took double the appropriate warfarin dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Colloid oncotic pressure as a guide for the anesthesiologist in directing fluid therapy.

One useful but underused parameter of fluid replacement is colloid oncotic pressure. Colloid oncotic pressure (COP) is one of the Starling forces that maintain a balance between intravascular and extravascular fluid. Systemic and pulmonary circulations exhibit differences that limit the usefulness of COP manipulation in the treatment of pulmonary edema, especially that associated with hypoxic damage or pulmonary contusion. Systemic transcapillary fluid transport, however, is governed significantly by COP, and serial measurements of COP can serve as useful guides for colloid replacement. In this paper we present instances in which COP determinations were found to be clinically helpful, and discuss colloid replacement during surgery.

Anesthesia↗
PubMed1989

A rational approach to anaesthetic premedication.

Rational use of premedication for anaesthesia must always be modified and updated to keep pace with the evolving fields of anaesthesiology and surgery, as well as to meet changing patient needs and preferences. It is no longer axiomatic that all patients require, and therefore should receive, premedication. Unfortunately, a variety of traditional reasons have been proposed to justify routine premedication in many institutions. Smoothing induction, decreasing reflexes and arrhythmias, decreasing nausea and vomiting, decreasing pain, decreasing secretions, and producing sedation and amnesia have all been claimed historically as beneficial results of premedication. Modern anaesthetic agents and techniques have come a long way towards eliminating the routine need for premedication. In the preoperative period, the goal of an anxiety-free patient who is physiologically uncompromised requires an individualised approach based on experience and an adequate knowledge of current pharmacology. As our knowledge of potential problems associated with anaesthesia has expanded, we have added other classes of drugs such as the H2-histamine receptor blockers and antacids to our premedicant armamentarium. Outpatient and short-stay patients have further challenged our preoperative goal of an anxiety-free patient by requiring individuals to be 'street ready' within a brief period of time after surgery. Even for in-house elective procedures, not every patient is a candidate for routine premedication. A frank preoperative discussion is all that is necessary to effectively allay anxiety in many persons. In these and other special situations, this article will hopefully guide the reader toward a more rational approach to premedicating patients.

Barbiturates↗
PubMed1989

Marfan syndrome in the parturient.

Early recognition of the Marfan Syndrome and knowledge of its potentially lethal complications facilitates successful treatment of these individuals. It is through a joint effort by many specialist physicians such as the obstetrician, cardiologist, and anesthesiologist that these patients can be managed safely through pregnancy, labor, and delivery.

Adult↗
PubMed1988

Testing computer-controlled infusion pumps by simulation.

The pharmacokinetic behavior of intravenous anesthetic drugs can be described by two- or three-compartment models. Rapid achievement and maintenance of steady plasma concentrations of these drugs requires a complicated delivery scheme, perhaps best controlled by a computer. The authors developed a method of simulating the performance of a computer-controlled infusion pump from the differential equations describing drug transfer between compartments. They also derived a mathematically simple and flexible approximate solution to these equations using Euler's numerical method. They incorporated this approximate solution into a computer-controlled infusion pump for intravenous drugs. They tested their pump by simulating the administration of fentanyl to a hypothetical patient whose fentanyl pharmacokinetics were described by a three-compartment model. The exact analytical solution served as the standard of comparison. The approximation technique, using a 15-s interval between model updates, had a maximum error of 0.35 ng.ml-1, and rapidly converged on the exact solution. The simulations revealed oscillations in the system. The authors suggest that such simulations be used to evaluate computer-controlled infusion pumps prior to clinical trials of these devices.

Anesthetics↗
PubMed1988

Headache after lumbar puncture: review of the epidural blood patch.

The incidence of accidental dural puncture during epidural block is 2.9%; headache follows in as many as 76.5% of these patients. Treatment by injection of autologous blood into the epidural space has gained wide acceptance since its introduction in 1960, though it is contraindicated by blood dyscrasias, anticoagulant therapy, bleeding, and localized infection. The procedure is done by slowly injecting 15 to 20 ml of blood into the same interspace, no sooner than 24 hours after the original puncture. Serious complications are rare.

Blood Transfusion↗
PubMed1988

Beyond career choice: the role of learning style analysis in residency training.

A recent article in this journal took an important step toward rethinking the utility of behavioural instruments designated as learning style tests (Jewett et al. 1987). The authors of that paper made much of a distinction between the terms 'learning style' and 'learning preference'. However, the results of their study do not seem to substantiate a marked difference between the function of the Rezler Learning Preference Inventory (LPI) and Kolb's Learning Style Inventory (LSI) with which it was contrasted. The most important aspect of their paper was that it rescued the concept of learning style analysis from the arena of career choice prediction at the undergraduate level and applied these ideas to doctors who had already made their specialty selections and were actively engaged in residency training. Clinical instructors in teaching institutions have, for the most part, little or no formal background in educational principles. For these individuals, an easily comprehensible model of resident-instructor psychology can be very useful on a daily basis. This article reviews the authors' experience with the LSI and describes their utilization of Kolb's Experimental Learning Model in the areas of resident counselling and residency curriculum design. The results of two recent studies are also presented in which learning style was examined as a predictor of success in residency, and teacher-resident learning style distributions were shown to exhibit parallel relationships at four different anaesthesiology residency training programmes.

Anesthesiology↗
PubMed1987

Selection of anesthesiology residents.

The large numbers of medical graduates seeking residency training in anesthesiology have created a logistical problem for many programs. This difficulty and the recurrent phenomenon of the misplaced physician have prompted a search for better selection criteria and more efficient evaluation systems. The literature does not provide a concise description of the ideal resident candidate, but it does contain several approaches taken by a few individual teaching centers to improve applicant review procedures. Computer-assisted resident candidate selection (CARCS) is a three-phase system of preinterview screening, interview evaluation, and final ranking. Based on faculty criteria, the entire process uses data management technology that provides automatic calculation of selection parameters, sorting on any data field or combination thereof, and maintenance of a concise information profile for each candidate. CARCS allows equitable consideration of all who apply, with significant cost savings to both program and applicants. This paper reviews traditional methods of selecting anesthesiology residents, describes the CARCS system, and previews the future of resident candidate selection.

Anesthesiology↗
PubMed1985

Drug interactions in anesthesia.

The threat of adverse drug interactions increases daily as more and more drugs become available. All physicians should be familiar with the problems of drug interactions and their management. Careful preoperative evaluation and screening combined with limited prescribing can help to limit the magnitude of this problem.

Adrenergic beta-Antagonists↗