Kathryn S. Dawson

Frequency of anesthetic cardiac arrests in infants: Effect of pediatric anesthesiologists

STUDY OBJECTIVE To determine whether the presence of pediatric anesthesiologists decreases the frequency of anesthetic-related cardiac arrests in infants (children who are 1 year of age or younger). DESIGN A comparative retrospective study of anesthetics and cardiac arrests during a 7-year period. SETTING The main operating room (OR) suite of a large university hospital. PATIENTS All patients age 1 year or less undergoing surgical anesthesia from July 1983 through March 1990. INTERVENTIONS Computerized anesthetic and operative patients records were queried for patient age, ASA physical status, body weight, surgical procedure, intraoperative complications, and the identity of the attending anesthesiologist. In each case, it was determined whether a pediatric anesthesiologist was in attendance and whether a cardiac arrest due to anesthesia occurred. Pediatric anesthesiologists were identified as those with pediatric fellowship training or the equivalent. The study population was divided into two groups: (1) the pediatric anesthesiologist group, with 2,310 patients whose anesthetics were supervised by pediatric anesthesiologists; (2) the nonpediatric anesthesiologist group, with 2,033 patients. MEASUREMENTS AND MAIN RESULTS Mean age and weight were comparable in the two groups, and the distribution of physical status did not differ. No anesthesia-related cardiac arrests occurred in the pediatric anesthesiologist group; four anesthetic cardiac arrests occurred in the nonpediatric anesthesiologist group, for a frequency of 19.7 per 10,000 anesthetics. This difference between provider groups is significant (Fishers exact probability test, p = 0.048). CONCLUSIONS The results suggest that the use of pediatric anesthesiologists for all infants 1 year of age or younger might decrease anesthetic morbidity in this age-group.

Perinatal substance abusers : psychological and social characteristics

Forty perinatal substance abusers were administered multiple psychosocial, addiction, and psychological measures before beginning treatment. Results indicate that these patients are limited intellectually, educationally, financially, and emotionally. Psychiatric comorbidity was high, with 45% having non-substance abuse axis I diagnoses and 75% having confirmed (by two or more tests) axis II pathology. The most frequently identified axis I disorders were depression and anxiety. The most frequently detected personality disorders were antisocial, borderline, paranoid, and dependent. The average IQ was 87 (low average range) and nearly one third of the sample were found to be somewhat impaired intellectually. These data suggest that treatment programs must take psychological characteristics into account if they are going to succeed in helping these women achieve and maintain abstinence.

Interpreting plots of a multidimensional dose−response surface in a parallel coordinate system

The dose-response surface for a combination of drugs is a multidimensional figure. Consequently, it is not possible to view such a surface using orthogonal axes when the number of dimensions exceeds 3. Parallel axes have been used to represent hyperdimensional figures. This paper reports on the use of parallel coordinate axes to plot the dose-response surface and its contours of constant response (isobols) for a combination of drugs. It is shown that patterns formed by intersecting line segments in the parallel system can aid in the interpretation of the fitted dose-response surface. More generally, analytic results are developed that permit the ready visualization and characterization of interaction effects of a polynomial model.

Two Graphical Techniques Useful in Detecting Correlation Structure in Repeated Measures Data

Abstract Analysis of repeated measures data using a mixed model includes specifying a form for the covariance matrix of the within-subject observations. This reduction in the number of estimated parameters from the unspecified structure may improve the efficiency of inferences made. An implementation of this technique has been incorporated in the MIXED procedure of the SAS® statistical package, and includes a wide range of options for the structure of the covariance matrix. It is demonstrated that draftmans display plots and/or plots in a coordinate system with parallel axes can aid in visualizing the dispersion structure.

A statistical test for detecting and characterizing departures from additivity in drug/chemical combinations

In this paper, we propose a test of additivity in a combination of drugs/chemicals based on the interaction index. The test is developed for data resulting from an experiment involving single-agent exposure groups and s combination groups of interest. The testing procedure begins with an overall size a test of additivity with s degrees of freedom. When this test is rejected, single degree-of-freedom tests combined with post hoc corrections for multiple testing are developed to determine which dose combinations are associated with departure from additivity. The method is illustrated using data associated with a patent application for a two-drug combination.

Psychopathology in Substance Abusing Women Reporting Childhood Sexual Abuse

Abstract This study compared MMPI-2 profiles and evaluated the ability of the MMPI-2 and its two new post-traumatic stress scales (PK and PS) to discriminate women in outpatient substance abuse treatment reporting positive (n = 24) and negative (n = 69) child sexual abuse histories. T-tests revealed significantly higher mean scores for the sexual abuse group for the following scales: F, 1, 2, 3, 4, 6, 7, and 8. A discriminant analysis yielded a linear function of L, F, 3, 5, 8, and PK that correctly categorized 75% with positive histories and 77% with negative histories. The optimal cutoff PK score was 17, which correctly classified 75% and 46% of those reporting positive and negative abuse histories, respectively. These findings support early identification of abuse survivors among substance abusing women and suggests that the MMPI-2 may be useful in patient-treatment matching.

Attitude toward recovery and completion of a substance abuse treatment program

This study tested the ability of the Recovery Attitude and Treatment Evaluator (RAATE; Mee-Lee, Hoffmann, & Smith, 1992) to predict attrition from treatment for pregnant and postpartum substance abusing women. During the first month of treatment, the RAATE was completed by both the clinician and the patient. Three types of discharge status were considered: completion of the treatment program, dropping out of the program, and being administratively discharged. No group differences were found concerning the clinician version of the RAATE. Initial analyses of the patient version revealed that subjects who completed the program had lower ratings of resistance to treatment and continuing care compared to those who dropped out; further analysis suggested that those who completed less than 1 month of treatment exhibited the highest resistance. These results suggest the RAATE is a potentially effective tool for predicting early attrition from substance abuse treatment in this population.

A Simple Approach for Finding Estimable Functions in Linear Models

Abstract In some overparameterized linear models it can be difficult to determine which parametric functions are estimable. Students in linear models courses and data analysts usually rely upon intuition and/or trial and error methods to determine estimability. We suggest reducing the design matrix to row echelon form as a means of finding the structure of all estimable functions. We illustrate the procedure with two examples.

Qcis: a sas-based relational database/query system for the current index to statistics

A portable, menu-driven software system for the Current Index to Statistics (CIS) cumulative database is described. The SAS-based system converts the CIS datafiles into a relational SAS database and provides windows for users to easily define their queries. Query execution may occur in batch or interactive mode.