Air-activated chemical warming devices: effects of oxygen and pressure

Air-activated chemical warming devices use an exothermic chemical reaction of rapidly oxidizing iron to generate heat for therapeutic purposes. Placing these products in a hyperbaric oxygen environment greatly increases the supply of oxidant and thus increases the rate of reaction and maximum temperature. Testing for auto-ignition and maximum temperatures attained by ThermaCare Heat Wraps, Playtex Heat Therapy, and Heat Factory disposable warm packs under ambient conditions and under conditions similar to those encountered during hyperbaric oxygen treatments in monoplace and multiplace hyperbaric chambers (3 atm abs and > 95% oxygen) revealed a maximum temperature of 269 degrees F (132 degrees C) with no spontaneous ignition. The risk of thermal burn injury to adjacent skin may be increased significantly if these devices are used under conditions of hyperbaric oxygen.

Cisapride or metoclopramide to accelerate small bowel transit during barium follow-through examination?

BACKGROUND

Metoclopramide is commonly used to accelerate small bowel transit during barium follow-through (BaFT) examinations, but its action is unpredictable. Cisapride, commonly used to treat gastroesophageal reflux disease, also accelerates small bowel transit and may be a viable alternative. The two were compared in a prospective, randomized, blind study.

METHODS

Patients attending for BaFT were randomized to receive either 10 mg cisapride or 20 mg metoclopramide orally 1 h before the barium suspension. BaFT was performed by using a standard technique, and small bowel transit and study quality were compared. Patients also noted any side effects experienced.

RESULTS

Of 45 patients recruited, 27 received cisapride and 18 metoclopramide. Median transit time for the cisapride group was 30 min (range = 10-130 min) versus 67.5 min (range = 30-290 min) for the metoclopramide group (p = 0.019). Study quality was comparable. However, nine patients (33%) receiving cisapride experienced nausea versus only one subject (6%) receiving metoclopramide (p = 0.034).

CONCLUSIONS

This study suggests that cisapride is a more effective prokinetic agent than metoclopramide, but this benefit is offset by a higher incidence of side effects.