Charles B. Pittinger

Vaginal deliveries during profound curarization

Abstract The use of curare derivatives as adjuncts to anesthesia in obstetrics has been reported by Whitacre and Fisher 1 and others. 2–12 No instances of infant depression due to curarization have been reported with the therapeutic dosages employed, nor has the postpartum contractility of the uterus been reported as being adversely affected. Neuromuscular blocking of human fetal tissues by curarization has been demonstrated by Buller and Young. 13 Harroun, Beckert, and Fisher 14 reported normal reflex activity in a 4½ months fetus delivered after a thirty-five minute period of apnea in the mother during a curare-nitrous oxide anesthesia, and an uninhibited contractility of the postpartum uterus. On the basis of reported observations the contention that curare does not pass the placental barrier has been widespread. However, it is difficult to accept this concept because of the known placental transmission of other water-soluble drugs and because placental transmission of d-tubocurarine chloride from fetus to mother has been reported in rabbits. 13 Our interest in the use of d-tubocurarine chloride for obstetrical purposes centered on the question of placental transmission of the drug. The purpose of this study was twofold: to observe the clinical effects of d-tubocurarine chloride on infants delivered of profoundly curarized mothers, and to make chemical analyses of the curare content of cord bloods from these infants. Blank values were to be obtained in similar analyses of cord bloods from infants delivered of noncurarized mothers for comparison.

How up-to-date are current anesthesia and related textbooks?

The purchaser of a textbook hopes that it contains up-to-date information. Recentness of copyright date does not assure this important characteristic. Heretofore there has not been a quantitative technique for evaluating the timeliness of information in textbooks.A procedure to reflect vintage was devised and tested in 34 textbooks of anesthesiological interest. It consists in the derivations of the mean, median and mode for the dates of all bibliographic references, and the combination of these three values into a geometric mean. The latter was designated the “vintage index.” Subtraction of the vintage index from the copyright date provided a value called the “differential”; the smaller the differential, the more current the references, and presumedly, the text. “Up-to-dateness” was defined as 1,000 times the reciprocal of the differential. Mean annual percentage inputs of updated references in new editions of textbooks were also calculated.Differential values ranged discriminatively from 45 to 333; those for the mean annual percentage inputs of updated references ranged from 1.9 to 13.2 per cent among all the texts.Of ten pharmacology textbooks analyzed, the mean of the up-to-dateness values for the overall references was 153 ± 41 (SD); for the references associated only with the anesthesia chapters in these texts the mean was 118 ± 20 (SD). This difference represents a significant (P < 0.05) lag in up-to-dateness for the anesthesia chapters. Similarly, the mean for the annual percentage input values for updated references was 6.6 ± 1.3 (SD) per cent for the overall texts and 5.5 ± 1.0 (SD) per cent for the anesthesia sections (P ≈ 0.05). Reasons for these differences between the anesthesia and overall references were not determined.The procedure is considered both discriminative and practical for evaluating the up-to-dateness of textbooks. It provides useful information for comparing texts of similar nature and following trends of updating among various editions within a series of volumes.