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Biomedical subjects

K Whalen

Publications and source records attributed to K Whalen.

15 recordsLinked to original sources
PubMed2000

Emergence characteristics of sevoflurane compared to halothane in pediatric patients undergoing bilateral pressure equalization tube insertion.

STUDY OBJECTIVE: To compare the emergence characteristics of sevoflurane with halothane in pediatric patients having bilateral myringotomy and pressure equalization tube insertion using a highly standardized and common anesthetic technique. DESIGN: Prospective, randomized, double-blind study. SETTING: University hospital. PATIENTS: 43 ASA physical status I and II healthy pediatric outpatients scheduled for initial ear tube placement by one surgeon. INTERVENTIONS: Patients were randomized to receive either halothane or sevoflurane as their sole anesthetic drug for ear tube insertion. All patients as well as the research nurse grading emergence agitation were blinded to group assignment. No premedication was administered, and all patients received a standard dose of rectal acetaminophen for postoperative pain control. MEASUREMENT AND MAIN RESULTS: The primary outcome was the percentage of patients with emergence agitation, defined as thrashing behavior requiring physical restraint for greater than three minutes. Time to discharge from the postanesthesia care unit (PACU) and from the hospital were also compared. Sevoflurane patients had a greater incidence of emergence delirium: 57% versus 27% [95% CI (1.7%-58.1%) p = 0.047]. Time to discharge from the PACU and the hospital were longer for patients who received sevoflurane: 62 versus 50 min [95% CI (1.4-23.6) p = 0.02] and 102 versus 79 mins [95% CI (9.6-37.1) p = 0.003]. CONCLUSION: In our institution there is a trend toward greater emergence agitation in ear tube placement patients given sevoflurane versus halothane anesthesia. Further, (with our discharge criteria) patients are actually discharged from the PACU and the hospital faster when given halothane as a sole anesthetic when compared to sevoflurane.

Anesthesia, Inhalation↗
PubMed2000

Specific elements of a new hemodynamics display improves the performance of anesthesiologists.

OBJECTIVE: We tested the hypothesis that a monitoring display proposed by Blike et al. improves the performance of anesthesiologists. We measured the performance of anesthesiologists using the new display and compared it to their performance with a traditional display. We studied three different displays on how they affected recognition and differentiation of five etiologies of shock-anaphylaxis, bradycardia, hypovolemia, ischemia and pulmonary embolus. METHODS: The participants monitored heart rate, systemic arterial and pulmonary blood pressure, central venous pressure, and cardiac output during five shock states and five non-shock states. The resulting 10 data sets made up ten decision screens, which we presented randomly on a computer monitor to the subjects in one of three different formats (a Single Sensor Single Indicator (SSSI) Numeric display; an Object display; and an Object Minus Shapes display). Subjects used soft-buttons on a computer touch-screen monitor to: a) advance to the next display; b) differentiate a non-shock state from a shock state; and, c) select the etiology of shock state represented by the display (Figure 4). The internal clock and memory of the computer made the collection of data automatic. RESULTS: The subjects recognized a problem more rapidly with the help of a graphical "pointer on a reference scale" in both Object displays, but their accuracy had not improved in comparison to the SSSI Numeric display. The shape of the Object display improved performance of etiology determination compared to the Object Minus Shapes display and SSSI Numeric display. Testing (10 trials) was completed in less than 45 minutes. CONCLUSIONS: The new display with "emergent features" can improve the diagnostic performance of clinicians.

Anesthesiology↗
PubMed2000

Emergence agitation in paediatric patients after sevoflurane anaesthesia and no surgery: a comparison with halothane.

This study was designed to compare the emergence characteristics of sevoflurane with halothane anaesthesia in paediatric patients having no surgical intervention. We randomized 32 ASA I or II paediatric outpatients scheduled for magnetic resonance imaging scans to receive either halothane or sevoflurane anaesthesia. The primary outcome measure was the percentage of patients with emergence agitation, as defined by two different criteria. Time to discharge from the postanaesthesia care unit (PACU) and the secondary recovery unit (SRU) were compared. Sevoflurane patients had a greater incidence of emergence delirium when a high threshold for agitation was defined (33% vs. 0%, P = 0.010) and a lower threshold for agitation was applied (80% vs. 12%, P<0.0001). Discharge times from the PACU and the SRU were not different. We conclude that there is an increased incidence of emergence agitation with sevoflurane anaesthesia compared to halothane independent of any painful stimulus.

Ambulatory Care↗
PubMed1999

A graphical object display improves anesthesiologists' performance on a simulated diagnostic task.

OBJECTIVE: This study tests the hypothesis that a graphical object display (a data display consisting of meaningful shapes) will affect the ability of anesthesiologists to perform a diagnostic task rapidly and correctly. The diagnostic tasks studied were recognition and differentiation of five etiologies of shock--anaphylaxis, bradycardia, myocardial ischemia, hypovolemia, pulmonary embolus. METHODS: Data sets consisting of HR, Systemic Arterial BP, Pulmonary Arterial BP, CVP, and Cardiac Output were generated for five shock states and five non-shock states. The resulting 10 data sets were presented on a computer monitor to study subjects twice (first in an alpha-numeric format and then in the object format) for a total of twenty decision screens. Subjects used soft-buttons on a computer touch-screen monitor to: a) advance to the next display; b) differentiate a non-shock state from a shock state; and, c) select the etiology of shock state represented by the display (Figure 2). Data collection was automatic, using the internal clock and memory of the computer. RESULTS: Eleven anesthesiologists participated in this study. They completed a total of 3060 diagnostic decisions, half with each display format. Performance measures were time to decision and diagnostic accuracy. The object display improved no-shock recognition by 1.0 second and shock etiology determination by 1.4 seconds (p < 0.05). The object display also significantly improved accuracy for shock recognition by 1.4% and etiology determination by 4.1% (p < 0.05). Testing was completed in a time interval of <45 min per 10 trials. CONCLUSIONS: The primary finding of this study was that anesthesiologists using the object display format committed significantly fewer diagnostic errors when interpreting physiologic data. In addition, both the recognition of no-shock and the diagnosis of shock etiology were completed more rapidly when the object display was used. The major limitation of this initial trial is the simplicity of the test. Future investigation of the impact of the display on clinical decision making will require more realistic clinical scenarios with partial or full simulation to better understand the potential clinical impact.

Anesthesiology↗
PubMed1999

Above reproach: developing a comprehensive ethics and compliance program.

How can a healthcare organization improve the public's confidence in the conduct of its business operations? What can it do to ensure that it can thrive despite being the subject of public and governmental scrutiny and doubt? Healthcare providers must establish standards of conduct that are above reproach and ensure that those standards are clearly articulated and strictly adhered to. This article describes the merits of a comprehensive ethics and compliance program, suggests five basic elements of such a program--organizational support/structure, setting standards, creating awareness, establishing a mechanism for reporting exceptions, and monitoring and auditing--and then demonstrates how those elements should be applied in several high-risk areas. Fundamentally, an ethics and compliance program has two purposes: to ensure that all individuals in an organization observe pertinent laws and regulations in their work; and to articulate a broader set of aspirational ethical standards that are well-understood within the organization and become a practical guideline for organization members making decisions that raise ethical concerns. Every ethics and compliance program should contain certain fundamental aspects. First, the effort must have the active support of the most senior management in the organization. To instill a commitment to ethics and compliance absent a clear and outspoken commitment to such purposes by organization leaders is simply impossible. Second, an ethics and compliance program is fundamentally about organizational culture--about instilling a commitment to observe the law and, more generally, to do the right thing. Third, ethics and compliance are responsibilities of operating management (sometimes called line management). Although staff such as compliance officers are obligated to provide the necessary resources for a successful program and to design the program, such staff officers cannot achieve implementation and execution. Only operating managers can do that. Fourth, an ethics and compliance effort should be about the conduct of individuals, not about "checking the boxes" in a model plan or generating attractive written or educational materials. Such an effort is about individuals on a day-to-day basis knowing what is expected of them and doing it and about never compromising integrity, regardless of pressures faced. A great deal of progress has been made in healthcare organizations in the development of increasingly sophisticated ethics and compliance programs. A particularly energetic focus has been placed on these programs since formal government guidance regarding compliance programs was first issued in the laboratory area about two years ago and as more sophisticated automated monitoring tools have been developed. As ethics and compliance programs have become more sophisticated, certain best practices have been established. This discussion will set forth approaches to ethics and compliance in the context of what are believed to be illustrative best practices. Much of what is described here is descriptive of the efforts of Columbia/HCA Healthcare Corporation from October 1997 to the present; however, this article has been presented not as a mere descriptive piece but rather as a set of normative guidelines. We hope that other healthcare providers will find this to be of practical use. Provider settings pose certain unique challenges that are specifically addressed in this discussion; however, many of the issues raised can be adapted to other healthcare organizations. For simplicity's sake, because the authors of this article all work on a daily basis primarily with hospitals, the article is written from a hospital perspective.

Ethics, Institutional↗
PubMed1995

Ion dissociation reactions induced in a high-pressure quadrupole collision cell.

This work concerns a new high-pressure quadrupole collision cell, designed for triple-quadrupole mass spectrometers. This new collision cell operates at pressures up to 10 mTorr, an order of magnitude higher than conventional cells of this type. Previous investigations have concentrated upon the significant increases in transmission efficiency and in resolving power for fragment ions which result from the use of this new design. The present work reports an investigation into the nature of the dissociation reactions which can be induced by collisions in this high-pressure cell. Charge-site-remote fragmentations of a simple precursor ion were chosen as a test case, and were found to be observable at laboratory collision energies lower by a factor of 4-5 than those found previously to be necessary when using conventional low-pressure quadrupole collision cells. It was also shown that the charge-site-remote reactions were accompanied by the mixed-site-fragmentation reactions described by Tuinman and Cook (J. Am. Soc. Mass Spectrom. Vol. 1, p. 85 (1989)). Ionization of collision gas was observed in the case of xenon. Efforts to observe charge-site-remote fragmentations of peptide ions were marginally successful. Highly basic peptides, which have been problematic for sequencing by low-energy tandem mass spectrometry, did not yield useful fragment-ion spectra in the new cell. The fragmentation behaviour of protonated Leu-enkephalin, for which fragmentation pathways have been thoroughly studied previously, suggested that the observed spectra reflected integration of the fragmentation kinetics over a considerably longer time, thus involving many more reaction steps. These combined observations are considered in terms of a qualitative model based on a rapid decrease of ion kinetic energy during passage through the cell, with much longer residence times than for conventional quadrupole cells.

Amino Acid Sequence↗
PubMed1995

Reducing polypharmacy in extended care.

In this 5-year prospective study, we determined the feasibility of reducing polypharmacy in a long-term care institution by a systematic review of the pharmacy records. At 6-month intervals, the computer printout of all medications prescribed to patients in a 550-bed institution was reviewed. After patients taking more than 10 different drugs were identified, their physician was notified and was asked to review their medications according to specific guidelines. The number of patients taking 10 or more medications was reduced from 67, when the program was started, to 9. The average number of medications per patient was reduced from 5.5 to 4.6. This program reduced the prevalence of polypharmacy and had long-lasting effects on the physicians' prescribing habits. We also believe it led to improved patient care by reducing the potential for drug interactions and to cost savings for the pharmacy.

Aged↗
PubMed1993

Changes in bone mineral content and density after stroke.

The purpose of this study was to determine whether there are differences in bone mineral content and density between paralyzed and nonparalyzed sides of patients who had sustained strokes associated with unilateral muscle weakness, to determine the relationship between duration of stroke and degree of demineralization and to compare the degree of demineralization in upper and lower limbs. The bone mineral content and density were measured by dual photon absorptiometry (high resolution scanning mode, Lunar DP4) in ambulant patients with a history of single completed strokes associated with unilateral weakness. The bone mineral content and density of each limb was determined by the region of interest analysis program. In the 30 patients included in this study, the bone mineral content and density were significantly less on the paralyzed than on the nonparalyzed side. The degree of demineralization was more pronounced in the upper than in the lower limbs. The mean percentage differences in bone mineral content and density between paralyzed and nonparalyzed arms were 13.8% (P < 0.00001) and 7.95% (P = 0.0003), respectively, and between paralyzed and nonparalyzed legs the differences were 4.5% (P = 0.0012) and 3.42% (P = 0.0028), respectively. A better correlation was noted between the time elapsed since the stroke and the degree of demineralization in the upper limbs (r = 0.75, P < 0.0001), than in the lower limbs (r = 0.60, P = 0.0004). In conclusion, patients who have strokes associated with muscle weakness are at an increased risk of developing osteoporosis on the paralyzed side and particularly in the upper limbs.

Aged↗
PubMed1988

Semi-automated direct colorimetric measurement of creatine kinase isoenzyme MB activity after extraction from serum by use of a CK-MB-specific monoclonal antibody.

This semi-automated colorimetric assay for the MB isoenzyme of creatine kinase (EC 2.7.3.2) is based on a monoclonal antibody ("Conan-MB") specific for this isoenzyme and is a modification of a previously published method (Vaidya et al., Clin Chem 1986;32:657-63). A 0.64-cm bead coated with 2 to 3 micrograms of antibody is incubated with 100 microL of serum and 10 microL of 0.2 mol/L beta-mercaptoethanol for 1 h at room temperature, to extract CK-MB. The beads are washed with de-ionized water and incubated with CK substrate for 45 min at 37 degrees C. A solution containing trans-1,2-diaminocyclohexane-N,N,N', N'-tetraacetic acid, p-iodonitrotetrazolium violet, and diaphorase is added and the resulting colored product is measured at 492 nm. The standard curve is linear to 200 U of CK-MB per liter, and analytical recovery is 97-113%. Total assay CV for low (9.7 U/L) and high (50.7 U/L) quality-control materials was 14.1% (n = 1878) and 11.6% (n = 1842), respectively. CK-MB activity correlated well (r = 0.978, n = 226) with CK-MB measured by a two-site mass immunoassay, and 99.4% of samples with CK-MB greater than or equal to 12 U/L (n = 347) were verified by electrophoresis on agarose.

Adsorption↗
PubMed1987

Diversity of the effect of recombinant tumor necrosis factors alpha and beta on human myelogenous leukemia cell lines.

In vitro characteristics of response to recombinant tumor necrosis factors alpha (rTNF-alpha) and beta (rTNF-beta) were studied in six human myelogenous leukemia cell lines. Heterogeneity of the response to rTNF was observed, and one line (K562) was resistant. No enhancement of cell growth was noted in any cell line. The dose-response curves for rTNF-alpha were characteristically sigmoid, the maximum inhibitory effect occurring between 25 and 200 ng/mL. Nonresponsiveness within this range indicated resistance that could not be overcome, even with very high doses of rTNF alpha. A similar response of sensitive and resistant lines occurred after exposure to rTNF-beta. The clonogenic cells were more sensitive than the overall population to the action of rTNF alpha, and prolonged exposure was necessary for manifestation of the effect. Concomitant exposure to recombinant interferon-alpha (rIFN-alpha) increased the response of two cell lines to rTNF-alpha, but no clear synergistic action could be demonstrated. The addition of rIFN-gamma was without effect. Variations in the rTNF-alpha-induced proliferative response could not be explained by differences in the number of binding sites per cell or their affinity for rTNF-alpha. That the clonogenic cells showed a higher sensitivity than the whole population might indicate a preferential effect on more primitive, actively proliferating cells with high growth potential.

Cell Division↗
PubMed1976

N-Tropic variants obtained after co-infection with N- and B-tropic murine leukemia viruses.

Sc-1 cells co-infected with small XC plaque-forming N-tropic and large XC plaque-forming B-tropic murine leukemia viruses produced, in addition to parental types, progeny with the phenotype, large XC plaque morphology, and N-tropism. This phenotype remained stable through end point titration and plaque purification on NIH/3T3 cells and growth on BALB/3T3 cells. These N-tropic viruses (XLP-N virus) grow to unusually high titer and make very large XC plaques.

Animals↗
PubMedDate not supplied

Cerebrospinal fluid cytokine levels after surgery with spinal or general anesthesia.

BACKGROUND AND OBJECTIVES: Studies show that pain may cause neuroinflammatory changes in the spinal cord. These inflammatory changes could be caused by circulating factors such as plasma cytokines or could be a primary neuroimmune response of the central nervous system following peripheral nerve injury. To identify the possible effects of peripheral trauma and pain on the cytokine environment of the spinal cord, interleukin-6 (IL-6) and interleukin-10 (IL-10) concentrations in plasma and cerebrospinal fluid (CSF) were measured before and after hip replacement surgery. METHODS: The investigation used a prospective, observational design to measure cytokine levels in samples of plasma and CSF by enzyme-linked immunosorbent assay (ELISA). Samples were taken from surgical patients before and after surgery under general anesthesia or spinal anesthesia performed with or without a spinal catheter. Reference samples were also obtained from healthy control subjects. RESULTS: Both plasma and CSF levels of IL-6 increased substantially after major surgery with either general or spinal anesthesia. No significant correlation was observed between plasma IL-6 and CSF IL-6 levels, suggesting a central origin for increased CSF cytokine levels. IL-10 did not change in plasma or CSF after surgery. Plasma and CSF IL-6 and IL-10 cytokine levels were very low or undetectable in healthy controls. CONCLUSIONS: Major orthopedic surgery leads to elevated CSF levels of the proinflammatory cytokine, IL-6. The origin of increased CSF IL-6 may be central because there was no significant correlation with plasma levels.

Anesthesia, General↗