Multilumen central venous catheters in children: relative potential to perforate vessels. An in vitro study.

OBJECTIVE: Because cardiovascular perforation by a central venous catheter (CVC) is a serious complication of catheterization in pediatric patients, we conducted an in vitro study of the relative potential for perforation of a standard material by the tips of multilumen pediatric catheters. Since we could not simulate vessel tissue, we hypothesized that testing catheters on a standard material would show whether catheters varied in tendency to perforate such a material and thus indicate a "relative potential for perforation." METHODS: Each CVC protruding from a support tube was suspended in a water-filled Plexiglas chamber at a 90 degrees incident angle to a polyethylene film, which was made to bulge 6 mm into the CVC tip 120 times per minute by hydropressure. Perforation of the polyetheylene film was documented on a time-based, strip-chart recording of pressure change on the opposite side of the film. We recorded the number of pulsations required for the following catheters to perforate the polyethylene: Arrow flex tip, Cook polyurethane, Viggo hydrocath polyurethane, and Cook silicone CVCs of 4- and 5-Fr size with 2 or 3 lumens (n = 5 catheters of each type, each catheter being tested 5 times). RESULTS: The number of pulsations to perforation ranged from 1 +/- 0.4 SD to > 7000. CONCLUSIONS: This in vitro study of the worst-case condition (90 degrees incident angle between CVC tip and polyethylene film) indicates that pediatric multilumen CVCs vary significantly in their relative potential to perforate a standard material. We suggest that, when central venous catheterization is contemplated in children, in addition to insertion site, catheter length, and depth of insertion, the type of catheter is another variable to consider in order to minimize the chance of cardiovascular perforation by the CVC tip.

Calcification of the auricular cartilage: a case report and literature review.

We report a case of auricular calcification in an elderly man with a history of frostbite and normal serum calcium levels. The causes of calcification of the cartilage of the external ear are discussed.

Anesthesia during total electrical failure, or what would you do if the lights went out?

This case report describes anesthetic management and monitoring of a patient undergoing abdominal surgery during a 45-minute loss of electrical power. Physical examination, electrical devices with battery backup power, and mechanical devices provided essential monitoring of the patient. Other methods of ensuring the adequacy of ventilation, circulation, and monitoring during total electrical failure are discussed. To decrease the risk during power outages, the authors recommend the following: (1) preparation of an organized plan for such an event that includes ensuring that equipment has reliable backup sources of power; (2) proper maintenance of equipment and batteries; and (3) knowledge of the power requirements of anesthesia equipment and monitoring devices.

Behavior modification with culturally deprived school children: two case studies.

Techniques of behavior modification were employed with two second-grade Negro girls in a demonstration school for culturally deprived children to increase the girls' appropriate classroom behaviors. A classification system that provided for continuous categorization of behavior was used to code the children's behavior in two classroom situations. Data were also taken on the type, duration, and frequency of the teachers' verbal interactions. The study included four conditions: Baseline, Modification I, Postmodification, and Modification II. The treatment variable was positive social reinforcement-attention and approval contingent upon desirable classroom behaviors-which was presented, withheld, or withdrawn (timeout from social reinforcement). Withholding of social reinforcement was contingent upon inappropriate attention-getting behaviors. Timeout from social reinforcement was contingent upon behaviors classified as aggressive and resistive. After 25 days of Modification I, desirable behavior increased markedly for each girl. The teachers were then asked to return to their Baseline level of performance. The resultant behaviors demonstrated that for one girl, behavior was still primarily under the control of the treatment contingencies. For the second child, many desirable behaviors that had increased in frequency during Modification I remained high, but inappropriate behaviors increased. When treatment was reinstated, the amount of time spent in desirable behaviors increased and remained high for both girls. Three checks during the three months following data collection showed that these behaviors continued to remain high.