Lupus anticoagulant, antiphospholipid syndrome and cardiac surgery.

The presence of lupus anticoagulant and the related condition antiphospholipid syndrome present a challenge in cardiac surgery where measured anticoagulation may not reflect the in vivo patient status of hypercoagulation. We report the successful management of a patient with lupus anticoagulant presenting for aortic valve replacement and coronary revascularisation. We used heparin for anticoagulation, specialised additional tests of anticoagulation and a reduced protamine dose. We also used tranexamic acid. The clinical problems with anticoagulation in patients with lupus anticoagulant include anticoagulant choice, measurement of adequate anticoagulation, antifibrinolytic usage, protamine dosing and blood product transfusion.

Managing aggressive thoughts and feelings with daily counts of non-aggressive thoughts and feelings: a self-experiment.

This article describes a self-experiment with a participant managing aggressive thoughts and feelings. The participant counted occurrences of aggressive thoughts and feelings per 24 h, and displayed these data on Standard Celeration Charts. Our experimental questions addressed the effects of daily 1-minute counts of non-aggressive thoughts and feelings, and daily distributed series of six 10-second counts of non-aggressive thoughts and feelings on the occurrences of aggressive thoughts and feelings. We used an A1-B1-C1-B2-C2-A2 experimental design to analyze data from the 1-minute counts and the six 10-second distributed counts as these conditions alternated around two baseline conditions. Compared to the baseline, less aggressive thoughts and feelings occurred during both independent variable conditions. The six 10-second distributed counts produced lower frequencies of aggressive thoughts and feelings than the 1-minute counts. At the end of the second six 10-second counting procedure and during the second baseline, the participant most frequently had 0 aggressive thoughts and feelings per day.

Nitrous oxide-isoflurane anesthesia causes more cerebral vasodilation than an equipotent dose of isoflurane in humans.

To compare the cerebral vascular and metabolic effect of an isoflurane-nitrous oxide mixture to an equipotent dose of isoflurane at 1.1 minimum alveolar anesthetic concentration (MAC), and to study the interaction between nitrous oxide and isoflurane anesthesia, we measured right middle cerebral artery blood flow velocity (V mca) and cerebral arteriovenous oxygen content difference (AVDO2) in six healthy patients during normocapnia and normothermia under the following sequence of steady-state anesthetic conditions: Condition A, 0.5 MAC of isoflurane, Condition B, 0.5 MAC of isoflurane + 0.6 MAC of N2O, Condition C, 1.1 MAC of isoflurane + 0.6 MAC of N2O, and Condition D, 1.1 MAC of isoflurane. The study entry sequence was randomized. V mca and AVDO2 during 1.1 MAC of isoflurane (Condition D) was 48 +/- 7 cm/s and 3.9 +/- 0.6 vol%, respectively. Substituting 0.6 MAC of isoflurane with an equipotent concentration of N2O (Condition B) resulted in an increase in both V mca and AVDO2 of approximately 20% (P < 0.05). These findings suggest that the increase in flow was accompanied by an even greater increase in metabolic rate. Adding 0.6 MAC of N2O to 1.1 MAC of isoflurane (Condition C) also increased V mca (P < 0.05). We conclude that N2O is a more potent cerebral vasodilator than an equipotent dose of isoflurane alone in humans.

Ogden R. Lindsley and the historical development of precision teaching.

This paper presents the historical developments of precision teaching, a technological offshoot of radical behaviorism and free-operant conditioning. The sequence progresses from the scientific precursors of precision teaching and the beginnings of precision teaching to principal developments since 1965. Information about the persons, events, and accomplishments presented in this chronology was compiled in several ways. Journals, books, and conference presentations provided the essential information. The most important source for this account was Ogden Lindsley himself, because Lindsley and his students established the basic practices that define precision teaching.

Observer reliability in detecting surreptitious random occlusions of the monaural esophageal stethoscope.

The esophageal stethoscope is used often during anesthesia to monitor ventilation and cardiac function. Deficiencies in observer vigilance may limit the effectiveness of this monitoring instrument. The aim of this study was to determine how long it took for an observer to detect a surreptitiously occluded monaural esophageal stethoscope in the setting of clinical anesthesia. During routine anesthesia, where an esophageal stethoscope was in use, a computer-guided device would artificially, silently, and at random time intervals, occlude the stethoscope tubing. Personnel using the stethoscope noted when they perceived the absence of stethoscope sounds. We studied 320 stethoscope occlusions in 32 patients. The time between stethoscope occlusion and detection was 34 +/- 59 seconds (mean +/- SD). Eighty-seven percent of detections were made in less than 60 seconds. However, 13% of detections were delayed for more than 60 seconds, and 2.3% for more than 240 seconds. While anesthesia personnel using an esophageal stethoscope could detect most stethoscope occlusions, failure to appreciate such episodes occurred in a small but significant number of cases. This suggests that the esophageal stethoscope has some definite limitations as a continuous monitor and that other monitoring techniques, such as oximetry, capnography, and ventilator disconnect alarms, as well as visual/tactile inspection of the patient, should be used as well.

The effects of feedback and consequences on transitional cursive letter formation.

Twelve first-grade students were employed to analyze the effects of (1) Verbal and Visual Feedback, (2) Verbal and Visual Feedback plus immediate rewriting of trained letters with one or more incorrect letter strokes, and (3) Potential Reinforcement on cursive letter strokes. Students practised both a set of trained and a set of untrained letters during each session. Feedback and reinforcement was administered only for trained letter strokes. The percentage of correct trained letter strokes increased during all conditions. Performance on the untrained but practiced and trained letter strokes followed the same general trend in response pattern. No consistent pattern of generalization was demonstrated with untrained and unpracticed letter strokes.

Students' self-recording of manuscript letter strokes.

A method to allow students to self-record manuscript letter strokes was applied to three groups of first-grade school children. These children learned to use plastic overlays in some 80 to 120 min, with agreement between students and experimenter concerning correctness averaging 79%, 82%, and 84% in the three groups. A practical method allowing children to record their letter writing, thus receiving immediate feedback appears to have been demonstrated.