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Biomedical subjects

N L Pace

Publications and source records attributed to N L Pace.

102 records · Page 6Linked to original sources
PubMed1979

Pharmacokinetics of naloxone and naltrexone in the dog.

The serum kinetics of 5 mg/kg of i. v. naloxone or naltrexone were studied in each of two groups of five dogs; serum samples were obtained from 2 min to 2 hr after injection. Serum concentrations were determined by radioimmunoassay. Serum levels of both naloxone and naltrexone fell rapidly; serum half-life during the elimination phase was 71.2 +/- 8.9 min (mean +/- S.E.) for naloxone and 85.1 +/- 9.0 min (mean +/- S.E.) for naltrexone. Although human and dog kinetics are similar for naloxone, naltrexone is long-acting in man, but is quickly dissipated in the dog.

Animals↗
PubMed1975

Indwelling pulmonary artery catheters. Their relationship to aspetic thrombotic endocardial vegetations.

To assess the incidence of aseptic thrombotic endocardial vegetations (TEV) after pulmonary artery catheterization with Swan-Ganz catheters we reviewed all autopsy reports for a two-year period in our hospital. In 413 autopsies there were five instances of aseptic TEV: 3 in 88 patients with Swan-Ganz catheters, 1 in 120 patients with central venous catheters, and 1 in the 205 patients without central vascular catheters. The incidence of TEV is significantly greater in patients with Swan-Ganz catheters than in other patients.

Adult↗
PubMedDate not supplied

Knowledge engineering using retrospective review of data: a useful technique or merely data dredging?

The process of extracting the knowledge or rules for medical decision making is not an easy task. One approach to knowledge engineering is to carefully review how decisions were made in the past with the goal of extracting the rules. The purpose of this project was to use previously collected data from ICU patients to derive the rules for the definition of hemodynamic stability. 97 ICU patients between 9/9/86 and 7/29/90 were included in the analysis. All of these patients had adult respiratory distress syndrome. Their mechanical ventilation was managed by a set of computerized protocols. We retrospectively searched the HELP system database for instructions that were not followed due to hemodynamic reasons. For each patient, we also chose one randomly selected therapy instruction which was followed to act as a control. For each instruction we then selected the corresponding hemodynamic data set. The data was then used in a stepwise logistic regression to determine the rules used for defining hemodynamic instability. We found that several of the hemodynamic parameters we had anticipated to be important were not even measured most of the time. The blood pressures and heart rate were almost identical between the hemodynamicly stable and unstable data sets. We conclude that the decision making process used by physicians has great variation, both between and within physicians. This makes knowledge engineering using retrospective techniques such as this prone to error and probably not very fruitful.

Bias↗
PubMedDate not supplied

Computerized management of patient care in a complex, controlled clinical trial in the intensive care unit.

Acute respiratory distress syndrome (ARDS) is often not responsive to conventional supportive therapy and the mortality rate may exceed 90%. A new form of supportive care, extracorporeal carbon dioxide removal (ECCO2R), has shown a dramatic increase in survival (48%). A controlled clinical trial of the new ECCO2R therapy versus conventional continuous positive pressure ventilation (CPPV) is being initiated. Detailed care protocols have been developed by 'expert' critical care physicians for the management of patients. Using a blackboard control architecture, the protocols have been implemented on an existing hospital information system and will direct patient care and help manage the controlled clinical trial. Therapeutic instructions are automatically generated by the computer from data input by physicians, nurses, respiratory therapists, and the laboratory. Preliminary results show that the computerized protocol system can direct therapy for acutely ill patients.

Blood Gas Analysis↗
PubMedDate not supplied

Epinephrine-induced arrhythmias: effect of exogenous prostaglandins and prostaglandin synthesis inhibition during halothane-O2 anesthesia in the dog.

Prostaglandins (PG) modify sympathetic and parasympathetic neurotransmission and have antiarrhythmic properties. Inhibitors of PG synthesis sensitize the heart to certain experimentally induced arrhythmias. This study examined the arrhythmogenic dose (AD) of epinephrine in dogs during halothane-O2 anesthesia as modified by the infusion of PG and by treatment with an inhibitor of PG synthesis. Dogs were anesthetized with 1.25 MAC halothane. The AD of epinephrine was established by a series of 3-minute epinephrine infusions at 10-minute intervals. The AD of epinephrine was then redetermined during infusions of PG(PGE1--1 microgram/kg/min and PGF2 alpha--1 microgram/kg/min), after indomethacin, 3 mg/kg, and after aminophylline, 10 mg/kg. The AD remained unchanged from control during both of the PG infusions and following indomethacin. Only following aminophylline did the AD decrease significantly. Our study suggests that pretreatment of surgical patients with nonsteroidal antiinflammatory drugs which inhibit PG synthesis does not increase the likelihood of ventricular arrhythmias during halothane-O2 anesthesia.

Aminophylline↗
PubMedDate not supplied

Failure of naloxone and naltrexone to antagonize halothane anesthesia in the dog.

The effects of two narcotic antagonists, naloxone and naltrexone, on minimum alveolar anesthetic concentration (MAC) were studied during halothane anesthesia in the dog. Following induction of anesthesia, MAC was determined in duplicate. Each dog was then given one of the two narcotic antagonists and MAC was redetermined in duplicate: five dogs were given naloxone, 3 mg/kg IV, followed by an intravenous infusion of naloxone, 0.025 mg/kg/min; five dogs received naltrexone, 5 mg/kg IV. MAC was unaffected by the narcotic antagonists. Failure of narcotic antagonists to reverse halothane anesthesia suggests that the endogenous opioid peptides are not involved in the anesthetic state produced by halothane.

Animals↗