pressed, purified air lowered the COHb level from 1.07% tO 1.00% during exercise. The exercise duration until angina was 324 seconds in the air control period and 330.3 seconds after purified air. However, the exercise duration before angina in the CO control period was. 321.7 seconds but only 289.7 seconds after breathing CO, which was a significant change. Breathing CO to raise the COHb from 1.09% to 2.02% also resulted in a significant depression of the prod- uct of blood pressure and heart rate at the onset of angina. Thus, patients with coronary artery disease may suffer del- eterious effects on exercise tolerance and myocardial oxy- gen delivery even when breathing low levels of CO. The suggestion is made that the United States Environmental Protection Agency should not relax present air quality criteria for CO. [Editor's note: Since CO can induce subse- quent coronary artery disease; this study confirms its dan- ger in patients with known angina. It is hard to compre- hend on what grounds the study was performed, and I am surprised that serious complications did not ensue./

William Jantsch, MD

DRUG SCREENING, COSTS

Cost e f fec t ive drug screen ing in the laboratory Sohn D, Byers J Clin Toxicol 18:459-469 Apr 1981

The authors present a method of studying the cost effec- tiveness of drag screening for toxic ingestions. They discuss the need to evaluate cost-risk, ie, risk to the Patient if a sUbstance is not identified and cost-benefit, ie, the benefits obtained from knowing qualitative information vs quanti- fication of the substances. Approximately ten substances account for two thirds of the drugs identified in urban tox- icoiogy labs. A small number of the common substances have specific antidotes and their identification can be help- ful. An even smaller group Of substances can best be treated by knowing quantitatively how much antidote is necessary. These drugs are discussed individually. The authors suggest only substances in the following categories should be iden- tified in drug screenings: drugs [hat produce life-threatening emergencies, drugs with rapid Onset of signs and symptoms, drugs which require early treatment to avoid serious com- plications, and drugs which have specific antidotes. The au- thors conclude though the cost of drug screening is high, intelligent use of the lab can eliminate some hospital

admissions or prevent prolonged ICU stays by he!ping to initiate early treatment. The total patient care cost package can thus be reduced. They feel more hospitals need to make a cost/benefit evaluation of their use of drug screens. [Edi. tot's note: With the exception of specific therapies ~Muco- myst ~ for acetaminophen), in general identifying the drug is less h i p than monitoring the clinical condition of the patient. In particular it is rare that a drug screen will make diagnosis of an unknown poisoning (possible exception is the patient with an acute orgamc brain syndrome).]

Frank Barber, MD

APPENDICITIS

Evolution of the distribution and mortality of acute appendicitis Pettokallio D TyKKa ~ Arch Surg 116:153-156 Feb 1981

Acute appendicitis is the most frequent reason for an emergency surgical operation. In this series of" 9.652 pa- tients operated on from May 1, 1952 to April 30. 1974 the character course, and. operative findings in patients with appendicitis confirmed at. operation were examined retro- spectively. There was a 0.27% mortality overall - - 0.12% of nonperforative appendicitis and 1.18% of perforative appen- dicitis. A rise in the proportion Of elderly patients corre- sponding with the rise in the average age of the population was found. Symptoms and clinical findings were noted to be similar in elderly and younger patients; however, the more rapid Progression of the disease in the aged was associated with a greater frequency of perforation in patients over 60 years of age. The greater mortality from acute appendicitis in the elderly (3.3%) is a consequence of their poorer recov- ery capacity and concomitant diseases as well as their great- er incidence of perforation. Rapid and accurate assessment and treatment in patients with possible diagnosis of appen- dicitis, especially in the elderly, is stressed. [Editor's note: It would be interesting to know how much the incidence of perforated appendix in the elderly correlates with the re. moval of normal appendices. Since the elderly are at such greater risk to die from the peritonitis of a ruptured appen- dix, one should strive to aggressively diagnose appendicitis prior to rupture even at the cost of an increased removal of normal appendices. One wonders about the current nega- tive feeling of incidental appendectomy in the elderly.]

Mont R. Roberts, MD

11:4 April 1982 Annals of Emergency Medicine 235/117