CORRESPONDENCE

3. Bonadio VCA, Wagner V: Efficacy of TAC topical anesthetic for repair of pediatric lacerations. AJDC 1988;142:203-205.

4. Adriana J, Campbell D: Fatalities following topical application of local anesthetics to mucous membranes. JAMA 1956;162:1527-1530.

Scleral Icterus May Be Unilateral To the Editor. We describe a unique case of a patient who presented with symp- toms suggestive of acute hepatitis and had deep icterus of one eye with the other eye being clear.

A 60-year-old woman was brought to the emergency department with a history of mild fever, anorexia, and recurrent vomiting for the previous three days. She also noted darkened urine one day before the onset of those symptoms. She denied chills, abdominal pain, hemetemesis, altered sensorium, passage of clay- colored stools, or intake of any drugs in the recent past. Examination revealed a well-built woman with blood pressure of 100/60 mm Hg; pulse, 106; and evidence of mild dehydration. Icterus was found to be absent in the left eve. Abdominal examination showed a 3-cm, mildly tender bepatomegaly with no free fluid or intercostal tenderness. The patient was fully alert and had no evidence of meningitis. Pupils were equal and reactive to light. However, the right eye was deeply icteric while the left eye was white. An ophthalmic examination done at that time was normal.

Investigations revealed a normal hemegram and electrolytes. The serum bilirubin was 9.8 mg/dL (166.6 pmol/L), direct being 7.0 mg/dL (119 pmol/L). An ultrasound of the abdomen revealed no liver abscess or choledocholithiasis. A diagnosis of acute hepatitis was made, and the patient was given injectable metaclopramide and IV fluids; this resulted in improvement in her symptoms. She was discharged and later lost to fellow- up. The liver enzymes reported on the stored sample were ALT/AST, 456/445 IU/L; and alkaline phos- phatase, 314 IU/L.

Jaundice is the most conspicuous clinical manifestation of deranged bilirubin metabolism. It is evidenced by yellow pigmentation of the scler- ae, mucous membranes, and skin. In the scierae, it is discernible when the serum bilirubin concentration exceeds 2 to 2.5 mg/dL Staining of sclerae is attributed to the richness in the tissue of elastin, which has a high affinity for bilirubin. Therefore, when icterus occurs, it is always bilateral in the eyes.. Certain condi- tions, such as hypercarotenemia, lycopenmia, picric acid ingestion, or quinacrine therapy, may produce yellow skin, but the sclerae are not stained. 1 On the other hand, jaundice may be less prominent or absent in a paralyzed or edematous limb as compared with a normal limb. 2 However, to our knowledge, no case of unilateral scleral icterus has been described in the literature, and we are unable to give any satisfactory explanation for this unreported find- ing. This case is of significance to emergency physicians, who must examine both eyes of a patient before ruling out any significant jaundice.

Praveen Aggarwal, MD, DNB Subrato Saha, MD Anil Agarwal, MS Lakhi Ram Murmu, MS KRP Range Red, MS Department of Emergency Medicine All India Institute of Medical

Sciences New Delhi, India 1. Lumeng L, O'Connor KW: Differential diagnosis of jaundice, in Ostrow JD (ed): Bile Pigments and Jaundice, ed i. New York, Marcel Dekker, Inc, 1986, p 475- 538.

2. Sherlock S: Diseases of the Liver and Bilia W System, ed 7. Oxford, Blackwell Scientific Publication, 1985, p 199-213.

911 Access and Trauma Deaths: A Complex Association To the Editor." We read with interest the article "A Population-Based Multivariate Analysis of the Association Between 911 Access and Per-Capita County Trauma Death Rates" [October

1992;21:1173-1178]. The authors have attempted to study an unvali- dated component of emergency medical services (EMS) that has been widely accepted.

Nevertheless, the outcome vari- able measured in the study does not accurately reflect the effect of 911 access on prehospital trauma care. Although the authors acknowledge the importance of ambulance response time, they do not measure its change as a result of the imple- mentation of 911 service. System configuration, dispatch protocols, and full-time provider availability must also be taken into account as determinants of ambulance response time. By examining only the county per-capita trauma death rates, the authors fail to address the various components of the EMS system that interact to affect patient outcome.

Furthermore, the data base accessed in the study includes all deaths "regardless of the time after injury that death occurs and regard- less of whether the victim reaches a hospital or a trauma center." It is difficult to imagine how an immedi- ate, unpreventable death or one occurring many days after the initial traumatic injury can be precluded by 911 access.

In conclusion, although the effect of 911 access on patient outcome must be assessed, it should be examined within the context of the EMS system as a whole.

Jonathan M flubb, MD Ronald G Pirrallo, MD, MHSA Department of Emergency Medicine Medical College of Wisconsin Milwaukee

To the Editor. We agree that the article represents an important step for this type of research and the authors and the state of North Carolina should be commended for their pioneering efforts. However, the study itself has several serious problems that cause us to question its conclusions.

The primary difficulty with this research is the authors' use of "per- capita death rates." While per-capi- ta rates may be commonly used in economics, in epidemiology or popu- lation-based research these are called "raw" or "crude" death rates. They are referred to as raw or crude

because they have not been adjusted for population characteristics such as age distribution or race. As an example, crude death rates for cancer may be high in Florida and low in Alaska, but most of this difference is because of the greater proportion of elderly in Florida and the fact,that cancer is a disease of the elderly.

Trauma is a disease with a specific age, sex; and race distribution (eg, homicide rates are highest among young black males). Counties in North Carolina vary considerably in age, race, and sex distribution. Therefore, if one uses per-capita or crude death rates, it is impossible to tell whether the negative results reflected the true relationship between 911 and trauma deaths, or whether it was an artifact of the counties' age, race, and sex distribu- tion. This problem could have been avoided if the authors had calculated age-adjusted rates for each sex and race group. This is standard practice in this type of research and the data are readily available.

The authors did try to account for age by examining percentages of persons over 65 years old in 911 versus non-911 counties. Whereas differences were present in bivariate comparisons, they were net present in the multivariate model. The more appropriate way to adjust for the dependent variable would have been to use age-adjusted rates for the dependent variable. And, since race was the most important variable in the multivariate mode, an even bet- ter approach would have been to use age-, race-, and sex-adjusted rates. In addition, to enhance comparison with future studies and other geo- graphic areas, it would have been helpful to know which International Classification of Diseases codes were included in calculating "trauma-related deaths."

A second major problem is the authors' application of a regression analysis that did net weigh the coun- ties by population. The populations of North Carolina counties vary tremendously, and thus the variance of the trauma death rate for each county will vary as well. Using the authors' methods, a small county with ten trauma deaths would be considered equiyalent to a county

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