Biomedical subjects

Lance J Oyen

Publications and source records attributed to Lance J Oyen.

9 recordsLinked to original sources

PubMed2006

Comparing intravenous amiodarone or lidocaine, or both, outcomes for inpatients with pulseless ventricular arrhythmias.

OBJECTIVE: To compare survival rates of patients with in-hospital cardiac arrest due to pulseless ventricular tachycardia/ventricular fibrillation treated with lidocaine, amiodarone, or amiodarone plus lidocaine. DESIGN: Multicenter retrospective medical record review. SETTING: Three academic medical centers in the United States. PATIENTS: Hospitalized adult patients who received amiodarone, lidocaine, or a combination for pulseless ventricular tachycardia/ventricular fibrillation between August 1, 2000, and July 31, 2002. MEASUREMENTS AND MAIN RESULTS: Data were collected according to the Utstein style. In-hospital proportion of patients living at 24 hrs and discharge were analyzed using chi-square analysis. Of the 605 patient medical records reviewed, 194 met criteria for inclusion (n=79 for lidocaine, n=74 for amiodarone, n=41 for combination). Available data showed no difference in proportion of patients alive 24 hrs post-cardiac arrest (p=.39). Cox regression analysis indicated a decreased likelihood of survival in patients with pulseless ventricular tachycardia/ventricular fibrillation as an initial rhythm as compared with those who presented with bradycardia followed by pulseless ventricular tachycardia/ventricular fibrillation and in those patients who received amiodarone as compared with lidocaine. However, only 14 patients (25%) in the amiodarone group received the recommended initial 300-mg intravenous bolus, and amiodarone was administered an average of 8 mins later in the code compared with lidocaine (p<.001). CONCLUSIONS: These results generate the hypothesis that inpatients with cardiac arrest may have different benefits from lidocaine and amiodarone than previously demonstrated. Inadequate dosing and later administration of amiodarone in the code were two confounding factors in this study. Prospective studies evaluating these agents are warranted.

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PubMed2006

Oxygen therapeutics: oxygen delivery without blood.

Nearly 14 million units of packed red blood cells are transfused in the United States each year. According to the U.S. Department of Health and Human Services, in 1999, 6% of hospitals reported a shortage of blood, resulting in the cancellation or postponement of surgical procedures. The many limitations and risks of transfusions of packed red blood cells in critically ill patients have facilitated interest in developing alternative agents for oxygen delivery. Over the past few decades, safe and effective substitutes have been in development. However, no currently approved agent provides both oxygen transport and volume in place of packed red blood cells. Oxygen therapeutic products have several advantages compared with packed red blood cells, including a prolonged shelf-life, lack of a cross-matching requirement, and minimal infectious risks or concerns about immunogenicity. Hemoglobin-based oxygen carriers and perfluorocarbons are being developed. Two products are undergoing clinical trials. Polyheme is undergoing a phase III study in trauma patients, and Hemopure is being evaluated in a phase II study in patients undergoing cardiopulmonary bypass surgery. A third product (Hemolink) was being evaluated in a phase III study in patients undergoing coronary artery bypass grafting surgery; however, the trial was suspended. In addition, several other hemoglobin-based oxygen carriers are in the preclinical stages. Oxygen therapeutics have several potential clinical applications in the management of perioperative blood loss, trauma, acute normovolemic hemodilution, traumatic brain injury, and blood requirements in patients who refuse or have contraindications to transfusions of red blood cells.

Blood Substitutes↗

PubMed2005

Hospital rules-based system: the next generation of medical informatics for patient safety.

PURPOSE: The hospital rules-based system (HRBS) and its subsystems at a major medical center are described. SUMMARY: The HRBS was implemented at the Mayo Clinic to rapidly identify and communicate crucial information to the clinician in order to optimize patient care. The system also enhances workload efficiency and improves documentation and communication. The system is used by the infectious-diseases division, pharmacy services, nutritional support services, infection control, and the nursing department. The six HRBS subsystems are Web-based programs that share a common structural design and integrate computerized information from multiple institutional databases. The integrated data are presented in a user-friendly format that improves the efficiency of data retrieval. Information, such as monitoring notes and intervention information, can be entered for specific patients. The subsystems use rules designed to detect suboptimal therapy or monitoring and identify opportunities for cost savings in a timely manner. CONCLUSION: The HRBS enhances the identification of drug-related problems while optimizing patient care and improving communication and efficiency at a major medical center.

Hospital Information Systems↗

PubMed2005

Interaction between dexamethasone treatment and the corticotropin stimulation test in septic shock.

OBJECTIVE: To review dexamethasone interaction with corticotropin stimulation testing, particularly as it applies to treating septic shock. DATA SOURCES: Pertinent literature was identified through MEDLINE (1966-February 2004) using combinations of the key words dexamethasone, adrenocorticotropic hormone stimulation, and pretreat. Only articles written in the English language and evaluating human subjects were considered. Reference lists of identified articles were reviewed for additional citations. DATA SYNTHESIS: Accurate interpretation of the corticotropin stimulation test is important to identify patients with septic shock who may benefit from corticosteroid supplementation. In healthy volunteers, short-term dexamethasone administration prior to the corticotropin stimulation test may depress the baseline cortisol level, but does not inhibit the response to the corticotropin challenge. This may result in a slight increase in the difference between baseline and post-stimulation values. CONCLUSIONS: In 2 small trials in healthy adults, short-term, low-dose dexamethasone pretreatment decreased baseline cortisol levels, but values following corticotropin stimulation were unaffected. Accordingly, caution in interpreting corticotropin stimulation test results is warranted. However, the application of the findings from these studies to patients with septic shock is difficult, given the important differences in physiology between normal and septic patients. As of December 29, 2004, a dexamethasone dose >2 mg or prolonged dexamethasone therapy (>2 days, totaling 4 mg) preceding corticotropin stimulation has not been studied in any population.

Adrenocorticotropic Hormone↗

PubMed2005

Effectiveness of a computerized system for intravenous heparin administration: using information technology to improve patient care and patient safety.

To overcome errors in prescribing, calculating doses, and monitoring intravenous heparin, a computerized heparin nomogram system (HepCare) was developed to improve heparin safety using interactive cues between the prescriber, nurse, pharmacist, and the laboratory. The frequency of deviations decreased from 0.5 per patient before HepCare with the protocol to 0.006 per patient with HepCare and the protocol. The goal activated partial thromboplastin time results of the HepCare system (group I) were compared with patients who were not treated using the HepCare system (group II). There was a higher mean percentage of activated partial thromboplastin times within goal range in group I vs. II-44% vs. 27% (p<0.01). There were reminders of a drop in platelet count in 6% of patients, hemoglobin drop in 0.7%, and validation activated partial thromboplastin time values in 7% of patients by HepCare. HepCare-guided intravenous heparin resulted in significant improvements in safety, quality assurance, and targeted activated partial thromboplastin time values.

Anticoagulants↗

PubMed2005

Agreement between bedside blood and plasma glucose measurement in the ICU setting.

STUDY OBJECTIVE: To assess the agreement between bedside glucose (bGlu) measurements and laboratory plasma glucose (pGlu) measurements in the ICU setting. DESIGN: Retrospective study. SETTING: ICU of a tertiary academic medical center. PATIENTS: One hundred ninety-seven patients admitted to the ICU from January through December 2002 who underwent 816 simultaneous bGlu and pGlu measurements. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: To calculate the agreement between the two methods of glucose measurement, the mean difference was obtained, and the limits of the agreement were calculated as the mean difference +/- 2 SDs. On 767 occasions, the mean bGlu was 159 mg/dL and the mean pGlu was 151 mg/dL (p < 0.001). The mean difference between the two techniques was 7.9 mg/dL (SD, 17.6 mg/dL), and the limits of agreement were + 43.1 and -27.2. On 31 occasions, the bGlu was reported as > 400 mg/dL, and in these cases the mean pGlu was 423 mg/dL (range, 300 to 900 mg/dL). On 18 occasions, the bGlu was reported as < 50 mg/dL, and in these cases the mean pGlu was 66.9 mg/dL (range, 13 to 198 mg/dL). CONCLUSIONS: On average, bGlu provides a reasonable estimate for pGlu. However, for the individual patient, bGlu gives an unreliable estimate for pGlu. All of those taking care of critically ill patients should be aware of the limitations of bedside glucometry.

Blood Glucose↗

PubMed2004

Fixed-dose vasopressin compared with titrated dopamine and norepinephrine as initial vasopressor therapy for septic shock.

STUDY OBJECTIVE: To investigate the early blood pressure effects of vasopressin compared with titrated catecholamines as initial drug therapy in patients with septic shock. DESIGN: Retrospective cohort, single-center study. SETTING: Intensive care units at the Mayo Clinic, Rochester, Minnesota. PATIENTS: Fifty, 49, and 51 intensive care patients treated initially with vasopressin, norepinephrine, and dopamine, respectively. INTERVENTION: Patients received either intravenous infusion of fixed-dose vasopressin 0.04 U/minute or titrated infusions of norepinephrine or dopamine for low systemic arterial pressures. MEASUREMENTS AND MAIN RESULTS: Patients treated with vasopressin, norepinephrine, and dopamine were similar in all measured characteristics except for their score on the Acute Physiology and Chronic Health Evaluation (APACHE) III (dopamine > vasopressin, p=0.049), renal comorbidities (dopamine > vasopressin, p=0.03) and baseline mean arterial pressure (MAP) (norepinephrine < vasopressin, p=0.005 or dopamine < vasopressin, p=0.05). In all patients, MAP 1 hour before and 1 hour afte intervention, heart rate, and systolic blood pressure were obtained. No treatment differences were identified in achieving postvasopressin MAP after adjusting for APACHE III score, renal dysfunction, and baseline MAP. In patients receiving vasopressin, 28-day mortality was 52%, similar to those receiving norepinephrine (65%, p=0.28) and dopamine (60%, p=0.53). CONCLUSION: Initial, fixed-dose vasopressin infusions increased MAP to 70 mm Hg or greater at 1 hour in intensive care patients with septic shock, similar to titrated norepinephrine or dopamine. Fixed-dose vasopressin appears appropriate as an alternative agent for hemodynamic support in patients with septic shock.

APACHE↗

PubMed2004

Dosing of unfractionated heparin in acute coronary syndromes.

Although the use of low-molecular-weight heparins for treatment of acute coronary syndromes (ACS) has increased in recent years, unfractionated heparin (UFH) remains the drug of choice for many patients and institutions. One reason is that this agent is safe for patients with renal dysfunction as well as those who undergo percutaneous coronary intervention or coronary artery bypass graft. The use of UFH is complicated by the increased risk of bleeding due to concurrent administration of numerous antiplatelet drugs in most patients with ACS, the limited data regarding ideal therapeutic range, and the wide variability of patient response. Knowledge regarding the optimal therapeutic range and how to achieve it efficiently may enable clinicians to improve clinical outcomes in patients with ACS. We reviewed and analyzed the available evidence to clarify how to best manage UFH therapy in patients with ACS. Current data support the use of a lower and narrower therapeutic range for patients with ACS than the range that is used for venous thromboembolism. Many factors in addition to weight affect patient response to UFH, including age, sex, diabetes mellitus, smoking status, and obesity.

Acute Disease↗

PubMed2002

A study of a weight-adjusted aprotinin dosing schedule during cardiac surgery.

UNLABELLED: Aprotinin is effective during cardiac surgery for reducing blood loss and transfusion requirements, but it is expensive. Aprotinin is usually administered to adults according to a fixed protocol regardless of the patient's weight. We previously developed a weight-based dosing protocol for aprotinin. The purpose of this prospective observational study was to determine aprotinin levels in four patient groups (n = 10 each) using the new weight-based aprotinin dosing schedule that should achieve concentrations over 100, 150, 200, and 250 kallikrein inhibitory units/mL compared with full-dose aprotinin regimen (n = 10) by a simple functional aprotinin assay. There was no difference in patient demographic or surgical variables among groups. There was less within patient variation in plasma aprotinin concentrations over time in the new weight-based aprotinin dosing schedule groups compared with the full-dose aprotinin regimen group (P < 0.02 for all comparisons). The mean plasma aprotinin concentration achieved with the new weight-based aprotinin dosing schedule was similar to the desired concentrations, but we were unable to reduce between-patient variability in aprotinin concentrations. IMPLICATIONS: The current dosing schedule for aprotinin results in a large variation in aprotinin plasma concentrations between patients and a large variation within each patient over time. A new weight-based dosing schedule reduced variation of aprotinin concentration over time, but was unable to reduce between-patient variability in aprotinin concentration.

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