ABSTRACTS

survival rate was 88.5%; when factors, 1, 4, and 5 applied, the rate was 21.4%; and when factors 3 and 4 applied, the rate was 10.3%. EMTDs can be trained to defibrillate safely but this technique did not affect outcome in a statistically significant manner for witnessed cardiac arrests in this rural area. It was concluded that the poor outcome of cardiac ar- rest victims in rural areas was primarily due to poor re- sponse times.

Mark W Elliott, MD

calcium, biochemical effects

nasogastric tube, which is passed orally into the mid- esophagus. Under fluoroscopic guidance, the magnet is ma- neuvered into the stomach and into contact with the for- eign body. Once secured, the foreign body is removed easily. This technique was used successfully in eight patients. The procedure takes less than three minutes and was tolerated well in all patients. It is proposed that this method may be used as an alternative to present methods of removal for all opaque foreign bodies, including batteries that contain iron and are located in the upper gastrointestinal tract.

Nicholas J Jouriles, MD

The acute biochemical effects of four proprietary calcium preparations Reid IR, Schooler BA, Hannan SF, et al Aust NZ J Med 16:193-197 1986

A prospective study involving ten healthy young men and women examined the effects of four different calcium sup- plements (Spar-Cal ®, Calcium Sandoz ®, Oc-Cal ® and Os- sopan ®) on several biochemical indices. Single oral doses containing I g elemental calcium each were administered in random sequence at least one week apart and blood samples were obtained one and three hours post ingestion. The in- vestigators observed significant increases in both ionized serum calcium and urinary calcium excretion accompany- ing a decline in serum parathyroid hormone and a signifi- cant rise in urine sodium excretion. These changes occurred acutely (within three hours of a calcium load) suggesting a rapid response in bone resorption. An unexpected finding of the study was the remarkable rise in urinary sodium excre- tion, 18 mmol sodium for each millimole increase in cal- cium excretion. This may further account for the previously reported rise in aldosterone following calcium loading. The authors postulate this as a contributing factor to volume depletion seen in patients with severe hypercalcemia and could lead to sodium depletion in the elderly on high dose calcium supplements. [Editor's note: This study was done on subjects 20 to 35 years old and the results may not be applicable to an elderly population. Further stuch'es may be required to validate these hypotheses.]

Michael Hunt, MD

venous acid-base, arterial acid-base, CPR

Difference in acid-base state between venous and arterial blood during cardiopulmonary resuscitation Weil MH, Rackow EC, Trevino R, et al N Engl J Med 315:153-156 Jul 1986

Bicarbonate administration during CPR usually is guided by arterial blood gas measurements. Speculation that this does not accurately reflect the acid-base status at the cel- lular level led to this study of 16 critically ill patients. Blood gas samples were drawn from indwelling pulmonary and ar- terial catheters during resuscitation. A state of "respiratory acidosis" was found on the venous side. The average arterial pH was 7.41, compared to a mixed venous pH of 7.15. The mean arterial PCO 2 was 32 m m Hg, but the mixed venous PCO 2 was 74 m m Hg. There was no significant difference between arterial and venous calculated bicarbonate content. The authors concluded that reduced pulmonary blood flow results in a buildup of carbon dioxide at the cellular level that arterial blood gases fail to reflect. Because carbon diox- ide buildup, and not bicarbonate loss, is occurring at the cellular level the authors also speculate that administering bicarbonate generates even more carbon dioxide in the blood and may reduce, rather than improve, cardiac func- tion.

John Neufeld, MD

ethanol, shock

foreign bodies, ingeshan, removal

Ingested foreign bodies: Removal by magnet Voile E, Hanel D, Beyer P, et al Radiology 160:407-409 Aug 1986

The authors describe their technique for removal of in- gested foreign bodies. A magnet is secured to the end of a

Ethanol impairs cardiocirculatory function in treated canine .hemorrhagic shock Horton JW Surgery 100:520-530 Sep 1986

Twenty-six mongrel dogs were studied to determine the effects of ethanol on cardiac function and regional blood flow in treated hemorrhagic shock. Fourteen dogs received intrajejunal ethanol to achieve a blood ethanol level of 276.

152/1371 Annals of Emergency Medicine 15:11 November 1986