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Biomedical subjects

T O'Connor

Publications and source records attributed to T O'Connor.

At least 145 records · Page 8Linked to original sources
PubMed1993

Intraoperative hemodynamic changes are not good indicators of myocardial ischemia.

Intraoperative myocardial ischemia is associated with an increased risk of a perioperative myocardial infarction (PMI) in patients undergoing coronary artery bypass graft surgery. If reversible physiologic variables could be identified that are indicators of myocardial ischemia, treatment might be instituted early to prevent cardiac morbidity. In patients undergoing elective coronary artery bypass graft surgery, we evaluated the relationship between several premorbid patient characteristics, selected hemodynamic variables, intraoperative myocardial ischemia, and a PMI. In addition we evaluated these selected hemodynamic variables as intraoperative indicators of myocardial ischemia. The following variables were evaluated: heart rate, > 80 beats/min; systolic arterial blood pressure, > 160 mm Hg; systolic arterial blood pressure, < 80 mm Hg; mean arterial blood pressure, < 60 mm Hg; pulmonary artery diastolic pressure, > 18 mm Hg; a 5 mm Hg increase in pulmonary artery diastolic pressure; rate pressure product, > 12,000 beats/min.mm Hg; and a pressure rate quotient, < 1.0 mm Hg/beats/min. The premorbid patient characteristics selected were previous myocardial infarction, recent myocardial infarction (within 1 wk of surgery), type and number of coronary lesions, beta-blocker therapy, and calcium blocker therapy. One hundred consecutive (n = 100) patients for elective coronary artery bypass graft surgery were studied prospectively before the initiation of cardiopulmonary bypass (CPB). Patients were monitored with a Hewlett Packard computer ST segment analyzer using leads II and V5. Ischemia was defined as the new onset of ST segment deviation of > or = 1 mm from the baseline electrocardiogram (ECG) (preinduction) for at least 2 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Act condemned.

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Economics, Nursing↗
PubMed1992

Adenotonsillectomy for upper airway obstruction carries increased risk in children with a history of prematurity.

To define better the clinical presentation and perioperative outcome in children undergoing adenotonsillectomy (T&A) for relief of upper airway obstruction (UAO), we reviewed the hospital records of 60 consecutive, otherwise normal children aged 12 years or younger. Seven patients with trisomy 21, neurologic impairments, or preoperative cor-pulmonale were excluded. Intraoperative and postoperative complications were experienced by 15 (34%) and 13 (25%), respectively, of the 53 children with preoperative UAO. The most severe complications comprised pulmonary edema and prolonged postoperative oxyhemoglobin desaturation. Multivariate logistic regression analysis found a history of prematurity and/or low birth weight to be the most significant risk factors related to the occurrence of complications. Twenty-eight % of the study population had a history of prematurity and they had approximately 85% of the perioperative complications seen in children with UAO undergoing T&A. Other significant risk factors included adenoidal facies and evidence of respiratory distress at the time of surgery. It appears that T&A poses significant risk for children with UAO who were born prematurely and have evidence of abnormal facial development or respiratory distress preoperatively.

Adenoidectomy↗
PubMed1992

Acute and multiple injection effects of magnesium on responding maintained by cocaine, extinction from cocaine, glucose + saccharin, and food.

In a variety of behavioral experiments, magnesium has effects that are similar to cocaine and other psychomotor stimulants. Of particular relevance to the present experiments is the recent finding that magnesium maintains responding in cocaine-trained rats. It would be expected, therefore, that injections of magnesium would alter the rate of responding maintained by self-administered cocaine in rats. Five experiments examined the specificity and selectivity of this interaction. Acute and multiple injections of MgCl2 (15-250 mg/kg) produced dose-dependent reductions in responding maintained by cocaine (0.1-2 mg/kg/infusion). Testing for acute injection effects occurred following injections, while testing for multiple injection effects occurred prior to daily injections. Doses of 30 and 125 mg/kg MgCl2 reduced responding maintained by doses of cocaine that were below the training dose of 0.75 mg/kg/infusion. MgCl2 in a dose of 250 mg/kg markedly suppressed responding maintained by each dose of cocaine. A magnesium-deficient diet produced a dose-dependent increase in responding maintained by 0.1 mg/kg/infusion cocaine. In order to determine the specificity and selectively of these effects, acute and multiple injections of MgCl2 were examined on glucose + saccharin- and food-maintained responding. The acute effects of MgCl2 injections were specific because food-maintained responding was not affected, except by the highest dose of 250 mg/kg. This demonstrates that lever pressing was not nonspecifically reduced by 30 and 125 mg/kg MgCl2 during cocaine availability. However, the effects on cocaine-maintained responding were not selective for cocaine because glucose + saccharin-maintained responding and responding during extinction from cocaine were affected by MgCl2 in a manner similar to cocaine-maintained responding.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Fetuses with Down syndrome have disproportionately shortened frontal lobe dimensions on ultrasonographic examination.

OBJECTIVE: The purpose of our study was to determine whether the frontal lobe is significantly smaller than normal in the Down syndrome fetus in midtrimester. STUDY DESIGN: Frontothalamic distance, measured from the inner table of the frontal bone to the posterior thalamus, and frontothalamic distance/biparietal diameter ratio were compared in 125 normal and 19 Down syndrome fetuses between 16 and 21 weeks' gestation. RESULTS: In the Down syndrome group 52% had frontothalamic distance < 10th percentile. When the frontothalamic distance and the frontothalamic distance/biparietal diameter ratio were expressed as multiples of the normal median to eliminate variation caused by gestational age, the mean value of multiples of the median in Down syndrome fetuses was compared with the mean value of multiples of the median in normal fetuses and was found to be significantly smaller (p < 0.0019 and p < 0.0177, respectively). When an observed-to-expected frontothalamic distance ratio of < or = 0.84 is used as a cutoff to screen for Down syndrome, sensitivity, specificity, and positive predictive values of 21.2%, 95.2%, and 1.2%, respectively, are achieved in a population with a 1:270 risk. CONCLUSION: Frontal lobe dimension is significantly shortened in Down syndrome fetuses.

Down Syndrome↗
PubMed1992

Predictive value of the human immunodeficiency virus 1 antigen test in children born to infected mothers.

Our objective was to examine the utility of the human immunodeficiency virus (HIV-1) antigen test as an early predictor of HIV-1 infection among children born to infected mothers and to collect information about its performance as a diagnostic test. The Abbott HIVAG-1 Enzyme Immunoassay was used to analyze serial serum samples from patients enrolled in a longitudinal cohort study of children born to mothers infected with HIV-1. There were 85 subjects who were followed from birth whose HIV-1 infection status could be definitely determined as of March, 1990. Of these 22 (26%) were infected with HIV-1 and 63 (74%) were uninfected. Overall the sensitivity of the test was 77% (95% confidence interval (CI), 55 to 92%) and the specificity was 97% (95% CI, 89 to 99%). The positive predictive value of a single positive test was 89% (95% CI, 67 to 99%) and of two or more positive tests was 100% (95% CI, 50 to 100%). The sensitivity of the test varied greatly with age. For 36 children from whom sera were collected during the first month of life the specificity of the antigen test was 100% but the sensitivity was only 20%. Overall in the first 6 months of life the sensitivity was less than 50%. The Abbott HIV-1 antigen test is useful as an early predictor of HIV-1 infection in children whose mothers are infected.

Child, Preschool↗
PubMed1992

Complications occurring in the postanesthesia care unit: a survey.

To identify and quantitate complications occurring in the postanesthesia care unit (PACU), a prospective study evaluated 18,473 consecutive patients entering a PACU at a university teaching hospital. Using a standardized collection form, the incidence of intraoperative and PACU complications was determined. The combined PACU and intraoperative complication rate was 26.7%. Data showed a PACU complication rate of 23.7%, with an overall intraoperative complication rate of 5.1%. Nausea and vomiting (9.8%), the need for upper airway support (6.9%), and hypotension requiring treatment (2.7%) were the most frequently encountered PACU complications. Patients in whom PACU complications developed were analyzed by ASA physical status. Of all patients experiencing nausea and vomiting (n = 1571), the highest percentage were ASA physical status II patients (n = 831). Likewise, in the group of 1450 patients who demonstrated a need for upper airway support, 792 were ASA physical status II. In patients experiencing a major cardiovascular complication, for example, variables associated with a greater risk of developing any PACU complications were ASA physical status (status II), duration of anesthesia (2-4 h), anesthetic technique, emergency procedures, and certain types of surgical procedures (orthopedic or abdominal). For patients admitted with a temperature of less than 35 degrees C the duration of the PACU stay was 152 +/- 46 min compared with 116 +/- 65 min for patients with a temperature greater than or equal to 36 degrees C (P less than 0.01). In conclusion, events occurring during the PACU period continue to be a source of patient morbidity.

Adolescent↗
PubMed1992

Community assessment.

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Community Health Nursing↗
PubMed1992

Prophylactic intravenous ondansetron in female outpatients undergoing gynaecological surgery: a multicentre dose-comparison study.

The efficacy and safety of prophylactic intravenous ondansetron in preventing postoperative nausea and vomiting was investigated in a randomized, stratified, double-blind, placebo-controlled, dose-comparison study of 580 ASA physical class I and II female outpatients undergoing gynaecological surgery and receiving general anaesthesia. Patients received either ondansetron 1, 4 or 8 mg, or placebo i.v. immediately prior to a standardized technique for induction and maintenance of anaesthesia. All patients were intubated and received nitrous oxide and a narcotic. All doses of ondansetron were significantly more effective than placebo in preventing emesis over the 24 h postoperative period. Ondansetron significantly decreased nausea and emesis scores over 24 h postoperatively without causing sedation. No changes in laboratory parameters (haematology, blood chemistry, and liver enzymes) or vital signs (heart rate, blood pressure, and respiratory rate) were observed. Headache and dizziness were the most common side-effects; however, their incidence was the same as with placebo. Ondansetron was generally well tolerated, as evidenced by an adverse event, laboratory safety, and vital sign profile similar to placebo. Ondansetron 4 mg was found to be the optimal prophylactic i.v. dose for female outpatients over the entire 24 h postoperative period. Higher doses may offer an added benefit in some patients, such as those with a history of nausea and vomiting following general anaesthesia.

Adult↗